US3897109A

US3897109A - Multi-wheeled excavating and loading system

Info

Publication number: US3897109A
Application number: US400043A
Authority: US
Inventors: Charles R Satterwhite
Original assignee: Southwest Equipment Developers Inc
Current assignee: SII 70% PARTNERSHIP; Krupp Industietechnik GmbH; Southwest Equipment Developers Inc
Priority date: 1972-03-27
Filing date: 1973-09-24
Publication date: 1975-07-29
Anticipated expiration: 1992-07-29

Abstract

In an excavating and loading system, an excavating wheel assembly comprises three excavating wheels each having a plurality of digging buckets. Each digging bucket is moved to the material receiving position during movement of the digging bucket through an initial portion of its rotation and to the material discharging position during a subsequent portion of its rotation. Material discharged from the digging buckets of the excavating wheel assemblies is received by conveyors and is transported thereby upwardly and rearwardly to a discharge point at the rear of the vehicle. The two outside excavating wheels of the excavating wheel assembly may be equipped with conical cutting members, whereby the excavation formed by the excavating and loading system is provided with tapered side walls.

Description

United States atent Satterwhite July 29, 1975 [54] MULTI-WHEELED EXCAVATING AND 3,690,023 9/ 1972 Peterson 37/ 190 X LOADING SYSTEM FOREIGN PATENTS OR APPLICATIONS [75] Inventor: Charles R. Satterwhite, Dallas, Tex. 137,833 2/1956 U.S.S.R 37/190 992,676 5/1965 U 'ted Kin d 37/190 [73] Asslgnee Swihwes Equ'pmem Devehpers 1,028,944 4/1958 Gigi-many 37/190 Inc-r Dallas 458,534 4 1928 Germany 37/190 I 7 590,853 1/1934 Germany 37/190 [22] Flled Sept 2 l9 3 900,536 12/1953 Germany 37/190 [21] Appl. No.: 400,043

Related Us. Application Data Primary Examiner-Clifford D. Crowder Attorney, Agent, or Firm-Richards, Harris & [63] Contmuation-in-part of Ser. No. 238,089, March 28, Medlock 1972, abandoned.

52 us. c1. 299739; 37/190; 37/DIG. 16; 1571 ABSTRACT 172/124; 299/67; 299/89 In an excavating and loading system, an excavating [51] Int. Cl E02f 3/24 wheel assembly comprises three excavating wheels [58] Field of Search 37/189, 190, 91, 94-97, each having a plurality of digging buckets. Each dig- 37/DIG. 16; 299/39, 53, 54, 75, 76, 78, 67, ging bucket is moved to the material receiving posi- 89; 198/9; 172/124 tion during movement of the digging bucket through an initial portion of its rotation and to the material dis- [56] References Cited charging position during a subsequent portion of its UNITED STATES PATENTS rotation. Material discharged from the digging buckets 109 273 11/1870 Thompson 172 124 x of the excavating Wheel assemblies is received by 1 005 544 10/1911 Henderson 37/189 "eyms and is transpmted thereby upwardly and 1:284:041 11/1918 Bager............: 37/D1G. 16 wardly a discharge Point at the rear of the vehicle 1,336,657 4/1920 Schmidt.. 37/189 The two outside excavating wheels of the excavating 1,858,327 5/1932 Hays 37/190 X wheel assembly may be equipped with conical cutting 2,748,505 6/1956 Turner.... 37/96 members, whereby the excavation formed by the exca- 2,984,025 5/1961 Winn 37/DIG- l6 vating and loading system is provided with tapered 3,052,455 9/1962 McLaughlin et a1 299/76 Side walls 3,101,932 8/1963 Wright 37/189 X 3,230,647 1/1966 Gates 37 190 45 Claims, 17 Drawing Figures N 354 27 290\ x 0 Q I I 2 298 334 i 344 ,1 e 300 j ,Js-

274 I ll F 296 41, i

302 21:12 fl'\ x E :3/6 I y I, I) ""-\I2 rs i! I 1 3 4 \1 332 P 4.5 1 r- 1 k 7 v 8, 222- 316 1 PATENTEDJULZQIHYS 3, 897, 109

SHEET 1 FIG. 3

PATENTED JUL 2 9 I975 SHEET PATENTED JUL29 1975 SHEET PATENTEU JUL 2 9 I975 SHEET PATENTED JUL 2 9 I975 SHEET SHEET PATENTEI] JUL 2 9 I975 FIG. [4

FIG. l5

PATENTED JUL 2 9 I975 SHEET FIG. I6

FIG.

MULTI-WHEELED EXCAVATING AND LOADING SYSTEM CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of copending application Ser. No. 238,089, filed Mar. 28, 1972, now abandoned.

BACKGROUND AND SUMMARY OF THE INVENTION This invention relates to excavating and loading systems, and more particularly to an improved excavating and loading system of the excavating wheel type.

Although an almost infinite number of excavating and loading systems have been designed heretofore, the need persists for considerable improvement in the art. For example, a typical loading machine available at the present time is capable of loading up to 1,700 cubic yards of earth per hour, has a gross weight of approximately 250,000 pounds, and sells for approximately $330,000. Furthermore, notwithstanding this relatively high cost and relatively low capacity, such a device is incapable of either ditching or forming a finished grade.

The present invention comprises a novel excavating and loading system which overcomes the disadvantages that have characterized the prior art. Thus, in one embodiment of the invention there is provided a machine capable of loading up to 4,000 cubic yards of earth per hour, having a gross weight of about 100,000 pounds, and having a selling price of approximately $150,000. Perhaps more importantly, excavating and loading systems incorporating the invention are capable of forming a finished grade in a single pass.

In accordance with the broader aspects of the invention an excavating and loading system comprises a vehicle, an excavating wheel assembly mounted at one end of the vehicle, and a conveyor which extends upwardly from a material receiving portion adjacent the wheel assembly to a material delivery portion at the opposite end of the vehicle. The excavating wheel assembly is greater in width than the remaining components of the system and comprises a plurality of digging buckets each including a wall which is supported for pivotal movement between a material receiving position and a material dumping position. Structure is provided for rotating the excavating wheel assembly and for operating the movable walls of the buckets to first receive material and to subsequently dump the material into the material receiving portion of the conveyor.

In accordance with a first embodiment of the invention, the vehicle comprises a main frame which is supported by a plurality of tired wheels. A first engine is supported on the main frame and functions to actuate the wheels to propel the vehicle and to actuate the conveyor to transport material thereon from the material receiving portion to the material delivery portion. A subframe is mounted at the top of the front end of the main frame and the excavating wheel assembly is rotatably supported on the subframe. The subframe also supports a second engine and a transmission which operatively interconnects the second engine and the excavating wheel assembly. An auxiliary conveyor is detachably supported at the rear of the main frame for receiving material from the delivery end of the conveyor and for transporting the material either rearwardly or laterally. A plurality of ballast tanks are mounted on the main frame for receiving liquid to counterbalance the weight of the auxiliary conveyor.

The excavating wheel assembly preferably comprises a center wheel and a pair of side wheels which are supported on the subframe for rotation about a common axis. In such a case cross conveyors are provided for transporting material from the side wheels to the material receiving portion of the main conveyor. The first engine preferably drives hydraulic pumps. This permits actuation of the propelling wheels, the main conveyor, the auxiliary conveyor, the auxiliary conveyor positioning means, and the cross conveyors by hydraulic motors operatively connected to the pumps.

In accordance with a second embodiment of the invention a motor is mounted on the subframe instead of the second engine, the vertical positioning of the material delivery portion of the main conveyor is lowered. and the auxiliary conveyor is removed. Structure is provided for pivoting the subframe to position the excavating wheel above and below the highest and lowest elements of the system, respectively. This permits use of the excavating and loading system in tunneling operations.

In accordance with a third embodiment of the invention the excavating wheel assembly is mounted on a subframe extending from the bottom of the front end of the vehicle. The vehicle is supported on tracks, and apparatus is provided for propelling the vehicle, actuating the conveyor, and actuating the excavating wheel assembly by means of a single engine. This embodiment of the invention also illustrates an alternative use of the excavating and loading system wherein the excavating wheels are rotated downwardly. This facilitates excavation of asphalt and similar materials in the form of relatively small pieces, as opposed to large plate-like sections of the material which might be encountered if the excavating wheels were rotated upwardly.

In accordance with a fourth embodiment of the invention the axis of rotation of the three excavating wheels comprising the excavating wheel assembly is offset angularly with respect to a line extending perpendicularly to the longitudinal axis of the vehicle. This is to prevent the formation of ridges between the excavating wheels during the use of the excavating and loading system in hard materials. In the operation of any of the various embodiments of the invention, the outside excavating wheels of the excavating wheel assembly may be equipped with cone-shaped cutter members, whereupon the excavation formed by the excavating and loading system is provided with tapered side walls.

DESCRIPTION OF THE DRAWINGS A more complete understanding of the invention may be had by referring to the following detailed description when taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a side view of an excavating and loading system comprising a first embodiment of the invention;

FIG. 2 is a partial top view of the excavating and loading system shown in FIG. 1;

FIG. 3 is a partial front view of the excavating and loading system;

FIGS. 4, 5 and 6 are enlarged side views of the rear, central, and forward portions of the excavating and loading system, respectively;

FIGS. 7 through 12 are illustrations of various systems for actuating the rear plates of the digging buckets of an excavating and loading system incorporating the invention;

FIG. 13 is a side view of an excavating and loading system comprising a second embodiment of the invention;

FIG. 14 is a side view of an excavating and loading system comprising a third embodiment of the invention;

FIG. 15 is an enlarged side view of the forward portion of the excavating and loading system shown in FIG. 14;

FIG. 16 is a top view of the forward portion of an excavating and loading system incorporating a fourth embodiment of the invention; and

FIG. 17 is an illustration of conical cutter members which may be utilized in conjunction with any of the various embodiments of the invention.

DETAILED DESCRIPTION Referring now to the drawings, and particularly to FIGS. 1 and 4 through 6, an excavating and loading system 20 incorporating a first embodiment of the invention is shown. The system 20 comprises a vehicle 22 including a main frame 24 which is supported by four wheels 26 for movement along a surface S. Each of the wheels 26 comprises a pneumatic tire 28 whereby the excavating and loading system 20 is adapted for movement over highways and other paved surfaces as well as for operation in unpaved areas, such as during an excavating operation.

A first engine 30 is supported on the main frame 24 of the vehicle 22. In accordance with the preferred embodiment of the invention, the first engine 30 is an internal combustion engine and functions to drive a plurality of hydraulic pumps 32. The pumps 32 in turn supply operating power for various components of the excavating and loading system 20. For example, one of the pumps 32 supplies operating power for a hydrostatic drive 34. The hydrostatic drive 34 is coupled to a transmission 36 including a brake 38. The transmission 36 provides dual outputs which are coupled to a forward differential 40 and a rear differential 42 by a plurality of drive shafts 44. Thus, the hydrostatic drive 34 operates by means of the wheels 26 to propel the excavating and loading system 20 both during excavating operations and during travel.

An excavating system comprises the forward portion of the excavating and loading system 20. The excavating system 50 includes a subframe 52 which is supported on a shaft 54 for pivotal movement relative to the vehicle 22 under the action of a pair of hydraulic cylinders 56. Operating power for the cylinders 56 is supplied by one of the pumps 32 which are driven by the first engine 30.

The excavating system 50 further includes an excavating wheel assembly 58 which is supported at the front end of the subframe 52. The excavating wheel assembly 58 is driven by a second internal combustion engine 60 which is supported at the rear end of the subframe 52. The engine 60 provides operating power for the excavating wheel assembly 58 but otherwise plays no part in the operation of the excavating and loading system 20. This arrangement has been found to be highly satisfactory for two reasons. First, it permits selection of the second engine 60 on the basis of the power requirements of the excavating system 50 only and not on the basis of the power requirements of the other components of the excavating and loading system 20. Also, due to its positioning at the rear of the subframe 52, the second engine 60 acts as a counterbalance for the weight of the excavating wheel assembly 58. This permits the use of hydraulic cylinders 56 of reduced size and also reduces the amount of power that is required in manipulating the excavating wheel assembly 58.

As is best shown in FIG. 6, a crumbing shoe 62 is supported at the front end of the vehicle 22 of the excavating and loading system 20 beneath the excavating wheel assembly 58. The crumbing shoe 62 is connected to the vehicle 22 by a pair of turnbuckles 64 and is also connected to the subframe 52. By this means the positioning of the subframe 52 under the action of the hydraulic cylinders 56 automatically correctly positions the crumbing shoe 62.

Referring now to FIGS. 2, 3 and 6, the excavating wheel assembly 58 comprises three excavating wheels 66A, 66B, and 66C, which are rotatably supported on the subframe 52 by a shaft 68 and a plurality of bushings 70. The secone engine 60 drives a speed reducer 72 which in turn drives a right angle drive 74. The right angle drive 74 actuates a pair of chain and sprocket drives 76 each including a sprocket 78 driven by the right angle drive 74, a chain 80 driven by the sprocket 78, and a sprocket 82 driven by the chain 80. As is best shown in FIG. 6, the chains 80 and the sprockets 82 are mounted within the subframe 52 and are therefore protected from damage due to accumulations of dirt, etc., during the operation of the excavating and loading system 20.

Each sprocket 82 is mounted on a shaft 84 which is rotatably supported in the subframe 52 and which in turn supports a pair of pinions 86. The pinions 86 are each mounted in mesh with a ring gear 88 mounted on one of the wheels 66 whereby the second engine 60 functions to rotate the wheels. In accordance with the preferred embodiment of the invention, the center excavating wheel 66B is provided with two ring gears 88 and is driven by two pinions 86, whereas the side excavating wheels 66A and 66C support a single ring gear 88 and are driven by a single pinion 86.

The excavating wheels 66 of the excavating wheel assembly 58 each include a hub 90 and a pair of rims 92 which extend radially outwardly from the hub. The excavating wheels comprise a plurality of digging buckets 94 which are equally spaced circumferentially around the hub 90 and which extend between the rims 92. The digging buckets 94 each have a cutting edge 96 including a plurality of teeth 98 and a stationary front wall 100 extending generally radially inwardly from the cutting edge 96. Each digging bucket further includes a rear wall 102 which is supported for pivotal movement between a digging position and a dumping position. The rear walls 102 of the digging buckets 94 are actuated by one of the mechanisms shown in FIGS. 7 through 12 and are manipulated thereby to the digging position when their respective digging buckets 94 are in the lower and forward portion of their rotary motion and to the dumping position when their respective digging buckets are in the upper and rearward portion of their rotary motion.

As is clearly shown in FIGS. 2 and 3, the three wheels 66A, 66B, and 66C comprising the excavating wheel assembly 58 have an overall width which exceeds that of the remaining components of the excavating and loading system 20. This has been found to be highly advantageous for two reasons. First, by increasing the width of the excavating wheel assembly 58 over that of a conventional ditching machine, an excavating and loading system incorporating the present invention is capable of excavating considerably more material with out increasing the speed of rotation of the excavating wheel assembly. Second, the fact that the excavating wheel assembly 58 is wider than the remaining components of the excavating and loading system permits operation of the excavating and loading system within the excavation that is being formed. This materially reduces the amount of movement of the excavating wheel assembly 58 that is necessary to position the assembly for excavating and for travel, and thereby reduces the overall complexity of an excavating and loading system incorporating the invention.

The excavating and loading system 20 further includes a loading system 110. The loading system includes a main conveyor 112 comprising an endless belt 114 mounted for movement around a course extending angularly upwardly relative to the main frame 24 of the vehicle 22 and including a material receiving portion 116 and a material delivery portion 118. More particularly, the course of the belt 114 is defined by a plurality of rollers 120 which are supported on a conveyor frame 122. The conveyor frame 122 is supported on the main frame 24 of the vehicle 22 and includes an upper portion 124 supported for pivotal movement about a horizontal axis under the action of a hydraulic cylinder 126. This permits control over the vertical positioning of the material delivery portion 118 of the conveyor 112.

The belt 114 of the main conveyor 112 extends around a relatively small drum 128 mounted at the upper end of the frame 122 and around a relatively large drum 130 mounted on the frame 24. The

drums

128 and 130 are rotated by radial

hydraulic motors

132 and 134, respectively. By this means the belt 114 is actuated for movement around the course defined by the rollers 120 to move material from the material receiving portion 116 to the material discharge portion 118. It has been found that the positioning of the

drums

128 and 130 causes a synergistic effect in that the drum 130 functions to cause the belt 114 to wrap more tightly around the drum 128 and thereby increase the effectiveness of the motor 132 in moving the belt 114.

A pair of cross conveyors'140 are also supported on the main frame 24 of the vehicle 22. The cross conveyors are driven by hydraulic motors 142 and function to receive material from the side excavating wheels 66A and 66C and to deliver the material to the material receiving portion 116 of the main conveyor 112. By this means all material that is excavated by the excavating wheel assembly 58 is delivered to the main conveyor 112 for transportation thereby from the material receiving portion 116 to the material discharge 118.

Referring now particularly to FIGS. 1 and 4, the preferred embodiment of the invention further includes an auxiliary conveyor system 150. The auxiliary conveyor system includes a frame 152 which is secured to the rear end of the frame 24 of the vehicle 22 by a plurality of pins 154. A turntable 156 is supported on the frame 152 for pivotal movement about a vertical axis under the action of a hydraulic motor 158.

A conveyor 160 is supported on the turntable motor 156 to receive material discharged from the material discharge portion 118 of the main conveyor 112. The conveyor 160 comprises a frame 162 which is supported on the turntable 156 and an endless belt 164 mounted for movement around a course defined by a plurality of rollers 166. The belt 164 is driven by a radial hydraulic motor 168, and a hydraulic cylinder is provided for controlling the angular relationship of the frame 162 to the turntable 156.

The auxiliary conveyor system 150 further includes a conveyor 172 comprising a frame 174 which is supported on the frame 162 of the conveyor 160 by a pair of parallel links 176. An endless belt 178 is supported on the frame 174 for movement around a course defined by a pair of drums 180. The conveyor 178 is driven by small hydraulic motors (not shown) mounted in the drums 180.

A hydraulic cylinder 182 extends between the frame 162 of the conveyor 160 and the frame 174 of the conveyor 172 for actuation to manipulate the conveyor 172 between the positions shown in full and in dashed lines in FIG. 4. When the conveyor 172 is positioned as shown in full lines in FIG. 4, it functions to receive material from the conveyor 160 and to discharge the material from the end of the excavating and loading system 20 remote from the excavating system 50. On the other hand, when the conveyor 172 is positioned as shown in dashed lines in FIG. 4 material is discharged directly from the conveyor 160. This arrangement is highly advantageous in that it permits the positioning of a dump truck or similar vehicle under the discharge end of the conveyor 160 while another vehicle is being loaded from the conveyor 172, and vice versa.

It will be appreciated that the hydraulic motor 158 may be actuated to pivot the turntable 156 and the

conveyors

160 and 172 supported thereon through an arc of approximately The excavating and loading system 20 may also be operated with the auxiliary conveyor system 150 removed, if desired. These conditions cause substantial changes in the overall weight distribution of the component parts of the excavating and loading system 20.

As is best shown in FIGS. 1 and 2, the vehicle 22 is equipped with a counterbalancing system comprising four

ballast tanks

192, 194 196 and 198 located at forward and rearward positions on opposite sides of the vehicle 22. In the use of the excavating and loading system 20, water is selectively pumped to and from the tanks comprising the counterbalancing system 190 whereby changes of the weight distribution of the excavating and loading system 20 caused by manipulations of the auxiliary conveyor system 150 are compensated for. Thus, if the excavating and loading system 20 is operated with the auxiliary conveyor system 150 removed, water is pumped out of the

tanks

194 and 198 and into the

tanks

192 and 196. Similarly, if the hydraulic motor 158 is operated to pivot the auxiliary conveyor system 150 towards one side of the vehicle 22, the tanks on the opposite side of the vehicle are filled with water whereby the change in weight distribution caused by the manipulation of the auxiliary conveyor system 150 is completely counterbalanced.

All of the hydraulic motors and all of the hydraulic cylinders comprising the loading system 110 are operatively connected to the pumps 32 which are driven by the first engine 30. Thus, the excavating and loading system 20 comprises separate excavating and

loading systems

50 and 110, respectively, which are driven by independent power sources. This arrangement has been found to be advantageous in that it permits optimum utilization of both systems. For example, in certain instances it may be necessary to provide maximum operating power to the excavating system 50 and to simultaneously provide maximum operating power to the loading system 110. Such a situation is accommodated much more readily by means of the present invention than would otherwise be possible.

Various systems for actuating the rear walls 102 of the digging buckets 94 of the excavating wheels 66A. 66B, and 66C are shown in FIGS. 7 through 12. In each instance the rear wall actuating system is located entirely within the margins of the excavating wheels. This may be compared with certain prior art systems characterized by external bucket wall actuating apparatus.

Referring particularly to FIG. 7, an actuating system 200 comprises a plurality of push rods 202 each of which is connected between one of the rear walls 102 and a chain 204. The chain 204 is generally unconstrained but extends around a roller 206 which is supported on the shaft 68 and which is secured against angular movement relative to the shaft 68 by suitable brackets (not shown). As the digging wheels are rotated about the shaft 68 under the action of the second engine 60, each push rod 202 comes into engagement with the roller 206 whereupon its respective rear wall 102 is pushed outwardly to the material dumping position. Subsequently, as each digging bucket is rotated to the lower and forward portion of its circular path. the chain operates through the push rod 202 to positively return the rear wall 102 to the material digging position. This positive actuation of the rear wall 102 in both directions has been found to be vastly superior to the arrangement that has been used heretofore wherein the rear portions were allowed to return to the digging position under the action of gravity.

An actuating system 208 that is similar in many respects to the system 200 is shown in FIG. 8. The system 208 incorporates a plurality of push rods 210 each connected between a chain 212 and the rear wall 102 of one of the digging buckets 94. The principal difference between the system 208 and the system 200 is that the chain 212 of the system 208 is equipped with a plurality of rollers 214. The rollers 214 are mounted for movement around a saddle 216 which is fixed to the shaft 68. By this means the rear wall 102 of the digging buckets 94 are positively actuated to the dumping position as each bucket is rotated to the upper and rearward portion of its circular path and is positively returned to the digging position as the bucket is rotated to the lower and forward portion of its path.

Another actuating system 218 is shown in FIG. 9. The system 218 includes a crank 220 which is fixed to the shaft 68. A collar 222 is rotatably supported on the crank 220, and a plurality of push rods 224 extend from the collar 222 to the rear walls 102 of the digging buckets 94. One of the rear walls 102 is connected to the collar 222 by a rod 226 which is fixed to the collar 222. By this means the collar 222 is constrained to rotate with the digging wheel whereby the

push rods

224 and 226 function to positively actuate the rear walls 102 to the dumping position when their respective digging buckets are in the upper and rearward portion of their travel about the shaft 68 and to positively return the rearward walls 102 to the digging position when their respective digging buckets are in the lower and forward portion of their travel.

Still another actuating system 228 is shown in FIG. 10. The system 228 comprises a plurality of cams 230 each fixed to one of the rear walls 102 of the digging buckets 94. The cams 230 are positioned for engagement with a roller 232 which is supported on an arm 234 that is fixed to the shaft 68. Each rear wall 102 is also provided with a spring 236 which functions to return the rear wall 102 to the digging position. Thus. upon rotation of a particular digging bucket to bring its cam 230 into engagement with the roller 232, the rear wall 102 of the digging bucket is actuated to the dumping position. As soon as the cam 230 comes out of engagement with the roller 232, the spring 236 returns the rear wall 102 to the digging position.

Referring now to FIG. 11, an actuating system 238 is shown. The system 238 comprises a cam track 240 which is supported on the shaft 68 and which is fixed against rotation with respect thereto. The rear wall 102 of each digging bucket 94 is equipped with a cam follower 242 including a roller 244 mounted in the cam track 240. The shape of the cam track 240 is such that each rear wall 102 is actuated to the dumping position when its digging bucket 94 is in the upper and rearward portion of its rotation about the shaft 68 and is returned to the digging position when its respective bucket 94 is in the lower and forward portion of its rotation.

Yet another actuating system 246 is shown in FIG. 12. In accordance with the system 246 a pneumatic cylinder 248 is provided for actuating the rear wall 102 of each digging bucket 94 between the digging and the dumping positions. Each pneumatic cylinder 248 is equipped with a valve 250 for controlling the flow of compressed air from a manifold 252 to the cylinder 248. Each valve 250 is in turn equipped with a cam follower 254 which functions to open its respective valve whenever it is moved inwardly.

The cylinders 248 and their respective valves 250 are mounted for rotation about the shaft 68 with the digging buckets 94 comprising the excavating wheels. A cam 256 is supported in fixed relation to the shaft 68. Thus. as each digging bucket rotates into alignment with the cam 256, its respective cam follower 254 is actuated by the cam 256. This operates the corresponding valve 250 to admit compressed air to its pneumatic cylinder 248, whereupon the rear wall 102 is actuated to the dumping position. In a particular arrangement shown. the rear walls 102 of the digging buckets 94 are returned to the digging position by individual springs 258. However, it will be understood that the actuating system 246 may be modified to provide for return of the rear walls 102 under pneumatic action, if desired. It will be further understood that the cylinders 248 can comprise hydraulic cylinders rather than pneumatic cylinders.

Referring now to FIG. 13, an excavating and loading system 20 comprising a second embodiment of the invention is shown. The excavating and loading system 20 is similar to the excavating and loading system 20 described hereinbefore in that it comprises a vehicle 22. an excavating system 50, and a loading system One difference between the system 20 and the system 20' is that the first and

second engines

30 and 60 of the system 20 are replaced with electric motors 30' and 60 in the system 20'. Another difference is that the electric motor 60' is positioned in a forward location and in that the angular positioning of the excavating system 50' is controlled by hydraulic cylinders 56 which are arranged somewhat differently from the hydraulic cylinders 56 of the excavating and loading system 20. This permits the cylinders 56' to pivot the excavating system 50 to points above and below the highest and lowest points on the remainder of the excavating system 20 and thereby adapts the excavating and loading system 20' to tunneling operations. The use of the excavating and loading system 20' in tunnel ing operations is further facilitated by the use of the electric motors 30' and 60 whereby the emission of dangerous exhaust gases is completely eliminated.

Referring now to FIGS. 14 and 15, there is shown an excavating and loading system 270 incorporating a third embodiment of the invention. The excavating and loading system 270 comprises a vehicle 272 including a main frame 274 supported on a pair of opposed track assemblies 276 for movement over a surface S. The track assemblies 276 are preferably conventional in design and comprise a pair of

sprockets

278 and 280 rotatably supported on a subframe 282 and in turn supporting an endless track 284. Each track assembly 276 further includes at least one motor (not shown) mounted on the subframe 282 and adapted for actuation by means of power supplied from a prime mover mounted on the vehicle 272 to propel the vehicle through one of the sprockets and the endless track 284 mounted thereon.

Each track assembly 276 is supported for pivotal movement relative to the main frame 274 of the vehicle 272 about the axis of the rear sprocket 280. A hydraulic cylinder 286 is provided on each side of the vehicle 272 and is connected between the main frame 274 of the vehicle and the subframe 282 of the adjacent track assembly 276. The hydraulic cylinders 286 are preferably actuated in tandem to control the angular relationship of the track assemblies 276 relative to the remaining components of the excavating and loading system 270.

As will be appreciated by those skilled in the art, the hydraulic cylinders 286 are typically initially actuated to lower the forward portion of the excavating and loading system 270. This causes the excavating and loading system to initiate a downwardly inclined excavation, whereby the excavating and loading system 270 digs itself into the cut or excavation to be formed. When the desired degree of inclination has been established, the hydraulic cylinders 286 are actuated to re turn the component parts of the excavating and loading system to the orientation illustrated in FIGS. 14 and 15, whereby the excavating and loading system continues to excavate on the established inclination until the desired depth of the excavation is reached.

The hydraulic cylinders 286 are then actuated to cause the excavating and loading system to form the bottom of the cut or excavation at a predetermined angular relationship with respect to grade. When the excavation has been finished, the excavating and loading system 270 can be removed by means of the inclination that was used to dig the excavation and loading system into the excavation. The hydraulic cylinders 286 may also be utilized to form an upwardly inclined ramp at the opposite end of the excavation, whereby the excavation and loading system 270 digs itself out of the excavation.

The excavation and loading system 270 further includes an excavating wheel assembly 290 which is preferably substantially identical in construction and operation to the excavating wheel assembly described hereinbefore in connection with the excavating and loading system 20. Thus, the excavating wheel assembly 290 comprises three excavating wheels spanning substantially continuously across the front of the vehicle 272 and having an overall width at least equal to that of the remainder of the excavating and loading system. The three excavating wheels 2992 are all rotatably supported on axles 294 by suitable bushings, and each wheel 292 comprises a series of digging buckets 296 which are substantially equally spaced around the periphery of the wheel.

The digging buckets 296 of the excavating wheels 292 comprising the excavating wheel assembly 290 each comprise a fixed bucket wall 298 extending inwardly from a plurality of replaceable digging teeth 300 of the type commonly used in excavation equipment. Each bucket 296 also includes a movable wall 302 supported for pivotal movement between a material receiving position and a material discharging position. Thus, as each excavating wheel 292 is rotated, the movable wall 302 of each digging bucket 296 comprising the wheel is first positively moved to the material receiving position and is subsequently moved positively to the material discharging position. Any of the various mechanisms illustrated in FIGS. 7 through 12 inclusive may be utilized for the actuation of the movable wall 302 of the digging buckets 296 comprising the excavating wheel assembly 290 of the excavating and loading system 270.

A major distinction between the excavating system 10 illustrated in FIGS. 1 through 6 and the excavating system 270 illustrated in FIGS. 14 and 15 involves the fact that the excavating wheel assembly 290 of the excavating and loading system 270 is supported on a subframe 310 which projects from the bottom of the front end of the vehicle 272 and which supports a crumbing shoe 311. The subframe 310 includes spaced, parallel portions 312 which extend between the excavating wheels 292 comprising the excavating wheel assembly 290 and which support the excavating wheels 292 by means of the axles 294. In the embodiment of the invention illustrated in FIGS. 14 and 15, the subframe 310 is fixedly mounted on the vehicle 272, and the hydraulic cylinders 286 comprise the sole means for adjustment of the inclination of the excavation formed by the excavating and loading system 270. However, it is also contemplated that the subframe 310 may be supported on the vehicle 272 for pivotal movement under the action of suitable hydraulic actuators connected between the frame 274 of the vehicle 272 and the subframe 310.

The excavating and loading system 270 is further distinguished from the excavating and loading system 20 in that a single engine 314 mounted on the vehicle 272 is utilized to supply all of the operating power for the excavating and loading system 270. The engine 314 drives a plurality of hydraulic pumps 316, which in turn supply operating power for many of the components loading system. The engine 314 further has an output shaft 318 which extends through a clutch 320 to a universal joint 322. The universal joint 322 connects the shaft 318 to a shaft 324 which extends to a right angle drive 326. The right angle drive 326 actuates a pair of relatively small diameter sprockets 328 which are coupled through a pair of chains 330 to a pair of relatively large diameter sprockets 332. The sprockets 332 drive a series of sprockets 334 which are mounted in mesh with ring gears 336 secured on the excavating wheels 292. By this means the output of the engine 314 is directly coupled to the excavating wheel assembly 290 through a drive train extending in part through the subframe 310 and hence between the three excavating wheels 292 comprising the excavating wheel assembly.

It will be understood that the spaced, parallel portions 312 of the subframe 310 comprise hollow boxlike members of the type illustrated in FlGS. 2, 3, and 6 in conjunction with the excavating and loading system 20. The spaced, parallel portions 312 therefore serve not only to support the excavating wheel assembly 290, but also to enclose the sprockets 328, the chains 330, and the sprockets 332 of the drive system for the excavating wheel assembly.

A major design feature of the excavating and loading system 270 involves the fact that the excavating wheel assembly 290 is supported on the subframe 310 by means of three axles 294 which are secured to the spaced, parallel portions 312 of the subframe 310 by means of flanges 294', and suitable fasteners. This leaves the interiors of the spaced, parallel portions 312 entirely open, whereby the diameters of the sprockets 332 may be selected to provide the particular speed and torque inputs to the excavating wheel assembly 290 that are required for a given excavating situation. On the other hand, if a single axle extending the entire width of the excavating wheel assembly were to be used, the maximum diameter of the sprocket 332 would be substantially restricted.

The ability to vary the speed and torque inputs to the excavating wheel assembly 290 by changing the sprocket wheels 332 has been found to comprise a substantial advantage. Thus, the operation is carried out quite easily by merely exchanging the sprockets 332 and adjusting the lengths of the chains 330. Moreover, changing the sprockets 332 does not effect the design criteria of the upstream components of the drive train. On the other hand, if another component of the drive train were to be changed in order to provide required torque and speed inputs to the excavating wheel assembly 290, various downstream components might also have to be changed in order to accommodate increased loads.

The excavating and loading system 270 further includes a loading system 340. The loading system 340 comprises a main conveyor 342 which receives excavated material directly from the center excavating wheel 292 of the excavating wheel assembly 290 and which transports the excavated material upwardly and rearwardly to a discharge point at the extreme rear end of the vehicle 272. The system 340 further includes a pair of cross conveyors 344 which receive excavated material from the two outside excavating wheels 292 of the excavating wheel assembly 290 and which transport the material to the main conveyor 342. As is best shown in FIG. 14, the rear portion of the main conveyor 342 is selectively pivotable about the axis ofa pin 346 under the action of hydraulic cylinders 348 mounted on the opposite sides of the vehicle 272.

The excavating and loading system 270 may also be provided with an auxiliary conveyor system 350. In such instances the auxiliary conveyor system 350 is connected to the extreme rear end of the frame 274 of the vehicle 272 and is utilized either to discharge the excavated material into trucks or other vehicles or to discharge the excavated material laterally with respect to the excavation being formed. The auxiliary conveyor system 350 is preferably identical in construction and operation to the auxiliary conveyor system described in detail hereinbefore in conjunction with the excavating and loading system 20.

An additional feature of the excavating and loading system 270 comprises an operators compartment 352 positioned at the top of the front end of the vehicle 272 to facilitate concurrent observation of all of the operating instrumentalities of the excavating and loading system 270. The operator's compartment 352 includes the usual operatorss seat 354 and a console 356 comprising the usual gauges, switches and controls which are necessary for complete regulation of the operation of the excavating and loading system 270.

FIGS. 14 and 15 further illustrate an alternative usage of excavating and loading systems incorporating the invention. As will be appreciated by those skilled in the art, the excavating wheels 292 of the excavating wheel assembly 290 are so constructed that the orientation of the center excavating wheel may be reversed with respect to the axle 294. Similarly. the outside excavating wheel 292 which is usually positioned on the right-hand side of the vehicle 272 may be mounted on the left-hand side thereof, and the excavating wheel 292 which is usually mounted on the left-hand side of the vehicle may be mounted on the right-hand side thereof. At the completion of these steps, the excavating wheels 292 comprising the excavating wheel assembly 290 are oriented as shown in FIGS. 14 and 15. It will be noted'that the orientation of the mechanism which actuates the movable walls 302 of the digging buckets 296 of the excavating wheels is preferably not changed as the orientation of the excavating wheels 292 is reversed. Thus, even though the excavating wheels rotate in the reverse direction, the movable wall 302 of each digging bucket 296 continues to be positively moved to the material receiving position as the digging bucket moves through the lower forward portion of its rotation and to be positively moved to the material discharging position as the digging bucket is moved through the upper rearward portion of its rotation.

The orientation of the excavating wheels 292 of the excavating wheel assembly 290 in the manner illustrated in FIGS. 14 and 15 is considered to be particularly advantageous for the excavation of asphalt paving and similar materials. Thus, with the excavating wheels so oriented, the digging teeth 300 of the digging buckets 296 are moved downwardly and therefore engage the pavement or similar matrerial from above. This produces an anvil effect so that the material is removed in the form of small pieces which are readily handled both by the excavating and loading system 270 and by the trucks or other vehicles which will be utilized to receive the excavated material. Conversely, if the excavating wheels 292 of the excavating wheel assembly 290 were operated in the conventional manner with the teeth 300 moving upwardly, the asphalt pavement or similar material might tend to break away in the form of large plate-like sections. Such sections have proven to be difficult to handle unless they are first further reduced to relatively small pieces.

Referring now to FIG. 16, there is shown an excavating and loading system 370 comprising a fourth embodiment of the invention. The excavating and loading system 370 comprises a vehicle 372 which is preferably substantially identical in construction and operation to the vehicle 22 described hereinbefore in conjunction with the excavating and loading system 20. An excavating wheel assembly 374 is supported at the front end of the vehicle 372 by means ofa subframe 376. The excavating wheel assembly 374 comprises three excavating wheels 378 extending substantially continuously across the front of the vehicle 372 and having an overall width at least equal to that of the remainder of the system. The excavating wheels 378 are preferably substantially identical in construction and operation to the excavating wheels utilized in the excavating and loading system 20.

In the operation of the excavating and loading system 370, material excavated by the center excavating wheel 378 is discharged onto a main conveyor 380 and is transported thereby to a discharge point at the rear of the vehicle 372. Material excavated by the two outside excavating wheels 378 is discharged onto a pair of cross conveyors 382 which in turn discharge the excavated material onto the main conveyor 380. The excavating and loading system 370 may also be provided with an auxiliary conveyor system similar to the auxiliary conveyor system 150 of the excavating and loading system 20, if desired.

The major distinction between the excavating and loading system 370 and the excavating and loading system comprises the fact that the axis of rotation of the three excavating wheels 378 comprising the excavatingwheel assembly 374 is angularly offset with respect to a line extending perpendicularly to the longitudinal axis of the vehicle 372. This has been found to be advantageous in the excavation of relatively hard mate rials in that it prevents the formation of ridges in the spaces between the excavating wheels comprising the excavating wheel assembly. The cross conveyors 382 are also angularly offset so as to be properly positioned to receive material excavated by the two outside excavating wheels 378. Nevertheless, the cross conveyors 382 discharge the excavated material onto the main conveyor 380 which extends parallel to the longitudinal axis of the vehicle 372.

The excavating wheel assembly 374 of the excavating and loading assembly 370 is driven by an engine 384 which is mounted on the subframe 3.76 and which is positioned so as to counterbalance the weight of the excavating wheel assembly 374. The engine 384 has an output shaft 386 which is coupled through a clutch 388 to a speed reducer 390 and hence to a chain drive 392. The chain drive 392 is in turn coupled through a shaft 394 to a right angle drive 396. The right angle drive 396 in turn functions to rotate the excavating wheels 378 of the excavating wheel assembly 374 by means of a pair of chain and sprocket drive mechanisms extending between the excavating wheels 378.

Those skilled in the art will appreciate the fact that due to the angularly offset positioning of the excavating wheel assembly 374, the excavating and loading system 370 functions to form an excavation extending between a plane 398 and a plane 400. This presents no problem except for the fact that the portion of the excavation adjacent the plane 398 is formed entirely bythe outside teeth of the excavating wheel 378 adjacent thereto. To

this end, the circular outside surface of the excavating wheel 378 adjacent the plane 398 may be provided with auxuliary cutting teeth 402 which function to assist in the formation of the adjacent portion of the excavation.

FIG. 17 illustrates an accessory which may be utilized in conjunction with any of the various embodiments of the invention described hereinbefore. Thus, the outside excavating wheels 410 of an excavating wheel assembly 412 incorporating the invention may be provided with conical cutter members 414. The cutter members 414 are detachably mounted and are preferably provided with replaceable cutting teeth 416 of the type commonly utilized in excavating machines of various types.

The purpose of the cutter members 414 is to form tapered side walls on the opposite edges of a cut or excavation formed by the excavating wheel assemblly 412. Assuming that the overall depth of the excavation does not exceed the radius of the excavating wheels 410. the side walls of the excavation will be tapered from top to bottom. On the other hand, if the total depth of the excavation exceeds the radius of the excavating wheels 410, only the lower portion of the side walls of the excavation will be tapered. In either event. it is often advantageous to provide tapered side walls on an excavation, particularly in those instances in which the material being excavated does not have sufficient substance to retain a vertical side wall configuration.

From the foregoing it will be understood that the present invention comprises additional improvements relating to the excavating and loading system disclosed and claimed in the copending application of Charles R. Satterwhite. filed Mar. 28, 1972, Ser. No. 238,089. Thus, in accordance with the third embodiment of the invention described herein, an excavating and loading system comprises a vehicle supported on tracks and an excavating wheel assembly supported on a subframe extending from the bottom of the front end of the vehicle. A single engine is utilized to provide operating power for all of the operating components of the excavating and loading system. The third embodiment of the invention further illustrates how the excavating wheels of an excavating and loading system incorporating the invention can be operated in the reverse direction to facilitate the excavation of asphalt pavement and similar materials.

In accordance with the fourth embodiment of the invention described herein, the excavating wheel assembly of an excavating and loading system incorporating the invention is mounted for rotation about an axis which is angularly displaced from a line extending perpendicularly to the longitudinal axis of the system. This is to prevent the formation of ridges between the excavating wheels of the excavating wheel assembly during the excavation of hard materials. The present application further discloses the use of conical cutter members secured to the outside excavating wheels of the excavating wheel assembly of an excavating and loading system incorporating the invention so as to form an excavation having tapered side walls.

Although particular embodiments of the invention have been illustrated in the accompanying drawings and described in the foregoing detailed description, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications, and substitutions of parts and elements without departing from the spirit of the invention.

What is claimed is:

1. An excavating and loading system comprising:

an excavating wheel assembly comprising axle means and at least two rigid excavating wheels rotatably mounted cantilever on and supported on the axle means, said excavating wheel assembly having a width at least equal to the widest portion of the remainder of the system;

each of said excavating wheels including a plurality of digging buckets located immediately adjacent one another to define the entire circumference of the excavating wheel, each bucket having a cutting edge which extends to a stationary wall and a wall mounted for pivotal movement from a material receiving position to a material dumping position;

supporting and housing means extending between the excavating wheels and connected to the axle means for supporting the excavating wheel assembly;

each of said digging buckets extending continuously between a side wall thereof located immediately adjacent to the supporting means and a side wall thereof defining one end of the excavating wheel assembly;

drive means extending through the supporting and housing means for rotating the excavating wheels so that the digging buckets follow a circular path;

said digging buckets being oriented and said drive means operating to move each digging bucket downwardly during the forward portion of its rotation such that the digging buckets are sequentially moved downwardly into engagement with material to be excavated whereby the material engaged by the digging buckets is supported by the ground below thereby allowing the digging buckets to cut off relatively small pieces of the material;

means located within the margins of the excavating wheel assembly and responsive to rotation of the excavating wheels for positively pivoting the movable wall of each digging bucket of the excavating wheels to the material receiving position when the bucket is in the lower and forward portion of the path and for positively pivoting the movable wall to the material dumping position when the bucket is in the upper and rearward portion of the path;

a vehicle for supporting and manipulating the excavating wheel supporting means and thereby positioning the excavating wheel assembly in engagement with material to be excavated; and

conveyor means mounted on the vehicle entirely behind the excavating wheel assembly for movement around a course including a relatively low portion positioned to receive material from the digging buckets of the excavating wheels upon the positioning of the movable walls of the buckets in the material dumping position and a relatively high material delivery portion located rearwardly on the vehicle from the low portion.

2. The excavating and loading system according to claim I further including a third excavating wheel supported on the axle means between the two cantilever supported excavating wheels, and wherein the excavating wheel supporting and driving means comprises spaced, parallel excavating wheel supporting and driving means extending between the center and the two side excavating wheels.

3. The excavating and loading system according to claim 2 wherein the conveyor means receives material from the center excavating wheel and further including means mounted on the vehicle behind the excavating wheel means for receiving material from the two side excavating wheels and for directing the material to the conveyor means for transportation thereby to the discharge point.

4. An excavating and loading system comprising:

an excavating wheel assembly comprising axle means and three rigid excavating wheels rotatably supported on the axle means, said excavating wheel assembly having a width at least equal to the widest portion of the remainder of the system;

each of said excavating wheels including a plurality of digging buckets, each bucket having a cutting edge which extends to a stationary wall, and a wall mounted for pivotal movement from a material receiving position to a material dumping position;

said three excavating wheels including a center excavating wheel comprising digging buckets spanning continuously between points immediately adjacent to the supporting and housing means and two side excavating wheels each comprising digging buckets spanning continuously from points immediately adjacent to the supporting and housing means to points defining the outer ends of the excavating wheel assembly;

means including a drive mechanism extending through the supporting and housing means for rotating the excavating wheels so that the digging buckets follow a circular path;

means located within the margins of the excavating wheel assembly and responsive to rotation of the excavating wheels for positively pivoting the movable wall of each bucket of the excavating wheels to the material receiving position when the bucket is in the lower and forward portion of the path and for positively pivoting the movable wall to the material dumping position when the bucket is in the upper and rearward portion of the path;

a vehicle for supporting and manipulating the excavating wheel supporting means and thereby positioning the excavating wheel assembly in engagement with material to be excavated;

conveyor means mounted on the vehicle behind the excavating wheel assembly for movement around a course including a relatively low portion positioned to receive material from each digging bucket of the center excavating wheel upon the positioning of the movable wall of the bucket in the material dumping position and a relatively high material delivery portion located rearwardly on the vehicle from the lower portion; and

means positioned on the vehicle behind the excavating wheel assembly to receive material from each digging bucket of the outside excavating wheels upon the positioning of the movable wall of the bucket in the material dumping position and for directing the material to the conveyor means.

5. The excavating and loading system according to claim 4 further including a conveyor frame supported on the main frame of the vehicle and extending angularly upwardly with respect thereto to define a course of the conveyor means, means supporting the upper portion of the conveyor frame for pivotal movement with respect to the lower portion thereof, an auxiliary conveyor supported at the rear end of the system for receiving material from the conveyor means, and means supporting the auxiliary conveyor for pivotal movement about a vertical axis.

6. The excavating and loading system according to claim 4 wherein the movable wall pivoting means comprises:

a plurality of push rods each connected at one end to the movable wall of one of the buckets;

a chain interconnecting the ends of the push rods remote from the movable walls; and

a member fixedly supported at a point over the material receiving portion of the conveyor means for cooperation with each push rod to move the corresponding movable wall to the material dumping position.

7. The excavating and loading system according to claim 4 wherein the movable wall pivoting means comprises:

a collar connected to the ends of the push rods remote from the movable walls;

means constraining the push rods to rotation with the buckets; and

means rotatably supporting the collar at a point offset from the axis of rotation of the buckets and thereby actuating the push rods to pivot the movable walls to the material dumping position when their respective buckets are positioned over the material receiving portion of the conveyor means.

8. The excavating and loading system according to claim 4 wherein the movable wall pivoting means comprises:

a spring connected to each movable wall for normally positioning the movable wall in the material receiving position;

a cam mounted on each movable wall; and

means positioned over the material receiving portion of the conveyor means for cooperation with the cams on the movable walls to pivot the movable walls to the material dumping position against the action of the springs.

9. The excavating and loading system according to claim 4 wherein the movable wall pivoting means further comprises:

a cam track disposed around the axis of rotation of the buckets; and

a plurality of cam followers each connected to one of the movable walls and each operatively engaged with the cam track for actuation thereby to pivot the movable walls between the material receiving and the material dumping positions.

10. The excavating and loading system according to claim 4 wherein the movable wall pivoting means comprises:

a plurality of cylinders each connected to one of the movable walls for actuation under fluid pressure to pivot the movable walls to the material dumping position; and

vavle means for controlling the actuation of the cylinders in accordance with the rotational positioning of the digging buckets.

11. The excavating and loading system according to claim 4 further including:

auxiliary conveyor means mounted for pivotal movement about a vertical axis; and

ballast means for selective actuation to counterbalance the auxiliary conveyor means.

12. The excavating and loading system according to claim 4 wherein the means for directing material from the two outside excavating wheels to the conveyor means includes cross conveyors for transporting excavated material inwardly to the conveyor means.

13. An excavating and loading system comprising:

each of said excavating wheels including a plurality of digging buckets located immediately adjacent one another to define the entire circumference of the excavating wheels, each bucket having a cutting edge which extends to a stationary wall, and a wall mounted for pivotal movement from a material receiving position to a material dumping position;

said drive means including drive chain means mounted for movement around a course extending in part through the supporting and housing means, a relatively large diameter sprocket mounted in the supporting and housing means and driven by the drive chain means, a relatively small diameter pinion driven by the sprocket, and a ring gear mounted on one of the excavating wheels and driven by the pinion;

means located within the margins of the excavating wheel assembly and responsive to rotation of the excavating wheels for positively pivoting the movable wall of each digging bucket of the excavating wheels to the material receiving position when the bucket is in the lower and forward portion of the path and for positively pivoting the movable wall to the material dumping position when the bucket is in the upper and rearward portion of the path; vehicle for supporting and manipulating the excavating wheel supporting means and thereby posi-

Claims

1. An excavating and loading system comprising: an excavating wheel assembly comprising axle means and at least two rigid excavating wheels rotatably mounted cantilever on and supported on the axle means, said excavating wheel assembly having a width at least equal to the widest portion of the remainder of the system; each of said excavating wheels including a plurality of digging buckets located immediately adjacent one another to define the entire circumference of the excavating wheel, each bucket having a cutting edge which extends to a stationary wall and a wall mounted for pivotal movement from a material receiving position to a material dumping position; supporting and housing means extending between the excavating wheels and connected to the axle means for supporting the excavating wheel assembly; each of said digging buckets extending continuously between a side wall thereof located immediately adjacent to the supporting means and a side wall thereof defining one end of the excavating wheel assembly; drive means extending through the supporting and housing means for rotating the excavating wheels so that the digging buckets follow a circular path; said digging buckets being oriented and said drive means operating to move each digging bucket downwardly during the forward portion of its rotation such that the digging buckets are sequentially moved downwardly into engagement with material to be excavated whereby the material engaged by the digging buckets is supported by the ground below thereby allowing the digging buckets to cut off relatively small pieces of the material; means located within the margins of the excavating wheel assembly and responsive to rotation of the excavating wheels for positively pivoting the movable wall of each digging bucket of the excavating wheels to the material receiving position when the bucket is in the lower and forward portion of the path and for positively pivotiNg the movable wall to the material dumping position when the bucket is in the upper and rearward portion of the path; a vehicle for supporting and manipulating the excavating wheel supporting means and thereby positioning the excavating wheel assembly in engagement with material to be excavated; and conveyor means mounted on the vehicle entirely behind the excavating wheel assembly for movement around a course including a relatively low portion positioned to receive material from the digging buckets of the excavating wheels upon the positioning of the movable walls of the buckets in the material dumping position and a relatively high material delivery portion located rearwardly on the vehicle from the low portion.

2. The excavating and loading system according to claim 1 further including a third excavating wheel supported on the axle means between the two cantilever supported excavating wheels, and wherein the excavating wheel supporting and driving means comprises spaced, parallel excavating wheel supporting and driving means extending between the center and the two side excavating wheels.

4. An excavating and loading system comprising: an excavating wheel assembly comprising axle means and three rigid excavating wheels rotatably supported on the axle means, said excavating wheel assembly having a width at least equal to the widest portion of the remainder of the system; each of said excavating wheels including a plurality of digging buckets, each bucket having a cutting edge which extends to a stationary wall, and a wall mounted for pivotal movement from a material receiving position to a material dumping position; supporting and housing means extending between the excavating wheels and connected to the axle means for supporting the excavating wheel assembly; said three excavating wheels including a center excavating wheel comprising digging buckets spanning continuously between points immediately adjacent to the supporting and housing means and two side excavating wheels each comprising digging buckets spanning continuously from points immediately adjacent to the supporting and housing means to points defining the outer ends of the excavating wheel assembly; means including a drive mechanism extending through the supporting and housing means for rotating the excavating wheels so that the digging buckets follow a circular path; said digging buckets being oriented and said drive means operating to move each digging bucket downwardly during the forward portion of its rotation such that the digging buckets are sequentially moved downwardly into engagement with material to be excavated whereby the material engaged by the digging buckets is supported by the ground below thereby allowing the digging buckets to cut off relatively small pieces of the material; means located within the margins of the excavating wheel assembly and responsive to rotation of the excavating wheels for positively pivoting the movable wall of each bucket of the excavating wheels to the material receiving position when the bucket is in the lower and forward portion of the path and for positively pivoting the movable wall to the material dumping position when the bucket is in the upper and rearward portion of the path; a vehicle for supporting and manipulating the excavating wheel supporting means and thereby positioning the excavating wheel assembly in engagement with material to be excavated; conveyor means mounted on the vehicle behind the excavating wheel assembly for movement around a course including a relatively low portion positioned to receive material froM each digging bucket of the center excavating wheel upon the positioning of the movable wall of the bucket in the material dumping position and a relatively high material delivery portion located rearwardly on the vehicle from the lower portion; and means positioned on the vehicle behind the excavating wheel assembly to receive material from each digging bucket of the outside excavating wheels upon the positioning of the movable wall of the bucket in the material dumping position and for directing the material to the conveyor means.

6. The excavating and loading system according to claim 4 wherein the movable wall pivoting means comprises: a plurality of push rods each connected at one end to the movable wall of one of the buckets; a chain interconnecting the ends of the push rods remote from the movable walls; and a member fixedly supported at a point over the material receiving portion of the conveyor means for cooperation with each push rod to move the corresponding movable wall to the material dumping position.

7. The excavating and loading system according to claim 4 wherein the movable wall pivoting means comprises: a plurality of push rods each connected at one end to the movable wall of one of the buckets; a collar connected to the ends of the push rods remote from the movable walls; means constraining the push rods to rotation with the buckets; and means rotatably supporting the collar at a point offset from the axis of rotation of the buckets and thereby actuating the push rods to pivot the movable walls to the material dumping position when their respective buckets are positioned over the material receiving portion of the conveyor means.

8. The excavating and loading system according to claim 4 wherein the movable wall pivoting means comprises: a spring connected to each movable wall for normally positioning the movable wall in the material receiving position; a cam mounted on each movable wall; and means positioned over the material receiving portion of the conveyor means for cooperation with the cams on the movable walls to pivot the movable walls to the material dumping position against the action of the springs.

9. The excavating and loading system according to claim 4 wherein the movable wall pivoting means further comprises: a cam track disposed around the axis of rotation of the buckets; and a plurality of cam followers each connected to one of the movable walls and each operatively engaged with the cam track for actuation thereby to pivot the movable walls between the material receiving and the material dumping positions.

10. The excavating and loading system according to claim 4 wherein the movable wall pivoting means comprises: a plurality of cylinders each connected to one of the movable walls for actuation under fluid pressure to pivot the movable walls to the material dumping position; and vavle means for controlling the actuation of the cylinders in accordance with the rotational positioning of the digging buckets.

11. The excavating and loading system according to claim 4 further including: auxiliary conveyor means mounted for pivotal movement about a vertical axis; and ballast means for selective actuation to counterbalance the auxiliary conveyor means.

13. An excavating and loading system comprising: an excavating wheel assembly comprising axle means and at least two rigid excavating wheels rotatably mounted cantilever on and supported on the axle means, said excavating wheel assembly having a width at least equal to the widest portion of the remainder of the system; each of said excavating wheels including a plurality of digging buckets located immediately adjacent one another to define the entire circumference of the excavating wheels, each bucket having a cutting edge which extends to a stationary wall, and a wall mounted for pivotal movement from a material receiving position to a material dumping position; supporting and housing means extending between the excavating wheels and connected to the axle means for supporting the excavating wheel assembly; each of said digging buckets extending continuously between a side wall thereof located immediately adjacent to the supporting means and a side wall thereof defining one end of the excavating wheel assembly; drive means extending through the supporting and housing means for rotating the excavating wheels so that the digging buckets follow a circular path; said drive means including drive chain means mounted for movement around a course extending in part through the supporting and housing means, a relatively large diameter sprocket mounted in the supporting and housing means and driven by the drive chain means, a relatively small diameter pinion driven by the sprocket, and a ring gear mounted on one of the excavating wheels and driven by the pinion; means located within the margins of the excavating wheel assembly and responsive to rotation of the excavating wheels for positively pivoting the movable wall of each digging bucket of the excavating wheels to the material receiving position when the bucket is in the lower and forward portion of the path and for positively pivoting the movable wall to the material dumping position when the bucket is in the upper and rearward portion of the path; a vehicle for supporting and manipulating the excavating wheel supporting means and thereby positioning the excavating wheel assembly in engagement with material to be excavated; and conveyor means mounted on the vehicle entirely behind the excavating wheel assembly for movement around a course including a relatively low portion positioned to receive material from the digging buckets of the excavating wheels upon the positioning of the movable walls of the buckets in the material dumping position and a relatively high material delivery portion located rearwardly on the vehicle from the low portion.

14. The excavating and loading system according to claim 13 further including a third excavating wheel supported on the axle means between the two cantilever supported excavating wheels, and wherein the excavating wheel supporting and driving means comprises spaced, parallel excavating wheel supporting and driving means extending between the center and the two side excavating wheels.

15. The excavating and loading system according to claim 14 wherein the conveyor means receives material from the center excavating wheel and further including means mounted on the vehicle behind the excavating wheel means for receiving material from the two side excavating wheels and for directing the material to the conveyor means for transportation thereby to the discharge point.

16. The excavating and loading system according to claim 13 further including: auxiliary conveyor means mounted on the vehicle for receiving excavated material from the conveyor means and mounted for pivotal movement about a vertical axis; a plurality of ballast tanks; and means for selectively directing liquid between the ballast tanks to counterbalance the weight of the auxiliary conveyor means.

17. An excavating and loading system comprising: an excavating wheel assembly comprising axle means and three rigid excavating wheels rotatably supported on the axle means, said excavating wheel assembly having a width at least equal to the widest portion of the remainder of the system; each of said excavating wheels including a plurality of digging buckets, each bucket having a cutting edge which extends to a stationary wall, and a wall mounted for pivotal movement from a material receiving position to a material dumping position; supporting and housing means extending between the excavating wheels and connected to the axle means for supporting the excavating wheel assembly; said three excavating wheels including a center excavating wheel comprising digging buckets spanning continuously between points immediately adjacent to the supporting and housing means and two side excavating wheels each comprising digging buckets spanning continuously from points immediately adjacent to the supporting and housing means to points defining the outer ends of the excavating wheel assembly; means including a drive mechanism extending through the supporting and housing means for rotating the excavating wheels so that the digging buckets follow a circular path; said drive mechanism including drive chain means mounted for movement around a course extending in part through the supporting and housing means, a relatively large diameter sprocket mounted in the supporting and housing means and driven by the drive chain means, a relatively small diameter pinion driven by the sprocket, and a ring gear mounted on one of the excavating wheels and driven by the pinion; means located within the margins of the excavating wheel assembly and responsive to rotation of the excavating wheels for positively pivoting the movable wall of each bucket of the excavating wheels to the material receiving position when the bucket is in the lower and forward portion of the path and for positively pivoting the movable wall to the material dumping position when the bucket is in the upper and rearward portion of the path; a vehicle for supporting and manipulating the excavating wheel supporting means and thereby positioning the excavating wheel assembly in engagement with material to be excavated; conveyor means mounted on the vehicle behind the excavating wheel assembly for movement around a course including a relatively low portion positioned to receive material from each digging bucket of the center excavating wheel upon the positioning of the movable wall of the bucket in the material dumping position and a relatively high material delivery portion located rearwardly on the vehicle from the lower portion; and means positioned on the vehicle behind the excavating wheel assembly to receive material from each digging bucket of the outside excavating wheels upon the positioning of the movable wall of the bucket in the material dumping position and for directing the material to the conveyor means.

18. The excavating and loading system according to claim 17 further including a conveyor frame supported on the main frame of the vehicle and extending angularly upwardly with respect thereto to define a course of the conveyor means, means supporting the upper portion of the conveyor frame for pivotal movement with respect to the lower portion thereof, an auxiliary conveyor supported at the rear end of the system for receiving material from the conveyor means, and means supporting the auxiliary conveyor for pivotal movement about a vertical axis.

19. The excavating and loading system according to claim 18 further including a ballast system comprising a plurality of tanks positioned at spaced points on the vehicle and means for selectively pumping liquid between the tanks and thereby counterbalancing the weight of the auxiliary conveyor.

20. The excavating and loading system according to claim 17 wherein the means for directing material from the two outside excavating wheels to the conveyor means includes cross conveyors for Transporting excavated material inwardly to the conveyor means.

21. An excavating and loading system comprising: an excavating wheel assembly comprising axle means and at least two rigid excavating wheels rotatably mounted cantilever on and supported on the axle means, said excavating wheel assembly having a width at least equal to the widest portion of the remainder of the system; each of said excavating wheels including a plurality of digging buckets located immediately adjacent one another to define the entire circumference of the excavating wheel, each bucket having a cutting edge which extends to a stationary wall, and a wall mounted for pivotal movement from a material receiving position to a material dumping position; supporting and housing means extending between the excavating wheels and connected to the axle means for supporting the excavating wheel assembly; each of said digging buckets extending continuously between a side wall thereof located immediately adjacent to the supporting means and a side wall thereof defining one end of the excavating wheel assembly; drive means extending through the supporting and housing means for rotating the excavating wheels so that the digging buckets follow a circular path; the axis of rotation of the excavating wheels being horizontally disposed and being angularly offset with respect to a line extending perpendicular to the longitudinal axis of the vehicle so as to prevent the formation of ridges in the spaces between the excavating wheels; means located within the margins of the excavating wheel assembly and responsive to rotation of the excavating wheels for positively pivoting the movable wall of each digging bucket of the excavating wheels to the material receiving position when the bucket is in the lower and forward portion of the path and for positively pivoting the movable wall to the material dumping position when the bucket is in the upper and rearward portion of the path; a vehicle for supporting and manipulating the excavating wheel supporting means and thereby positioning the excavating wheel assembly in engagement with material to be excavated; and conveyor means mounted on the vehicle entirely behind the excavating wheel assembly for movement around a course including a relatively low portion positioned to receive material from the digging buckets of the excavating wheels upon the positioning of the movable walls of the buckets in the material dumping position and a relatively high material delivery portion located rearwardly on the vehicle from the low portion.

22. The excavating and loading system according to claim 21 further including a third excavating wheel supported on the axle means between the two cantilever supported excavating wheels, and wherein the excavating wheel supporting and driving means comprises spaced, parallel excavating wheel supporting and driving means extending between the center and the two side excavating wheels.

23. The excavating and loading system according to claim 22 wherein the conveyor means receives material from the center excavating wheel and further including means mounted on the vehicle behind the excavating wheel means for receiving material from the two side excavating wheels and for directing the material to the conveyor means for transportation thereby to the discharge point.

24. The excavating and loading system according to claim 21 further including a conveyor frame supported on the main frame of the vehicle and extending angularly upwardly with respect thereto to define a course of the conveyor means, means supporting the upper portion of the conveyor frame for pivotal movement with respect to the lower portion thereof, an auxiliary conveyor supported at the rear end of the system for receiving material from the conveyor means, and means supporting the auxiliary conveyor for pivotal movement about a vertical axis.

25. The excavating and loading system according to claim 21 further including a ballasT system comprising a plurality of tanks positioned at spaced points on the vehicle and means for selectively pumping liquid between the tanks.

26. The excavating and loading system according to claim 21 wherein the movable wall pivoting means comprises: a plurality of push rods each connected at one end to the movable wall of one of the buckets; a chain interconnecting the ends of the push rods remote from the movable walls; and a member fixedly supported at a point over the material receiving portion of the conveyor means for cooperation with each push rod to move the corresponding movable wall to the material dumping position.

27. The excavating and loading system according to claim 21 wherein the movable wall pivoting means comprises: a plurality of push rods each connected at one end to the movable wall of one of the buckets; a collar connected to the ends of the push rods remote from the movable walls; means constraining the push rods to rotation with the buckets; and means rotatably supporting the collar at a point offset from the axis of rotation of the buckets and thereby actuating the push rods to pivot the movable walls to the material dumping position when their respective buckets are positioned over the material receiving portion of the conveyor means.

28. The excavating and loading system according to claim 21 wherein the movable wall pivoting means comprises: a spring connected to each movable wall for normally positioning the movable wall in the material receiving position; a cam mounted on each movable wall; and means positioned over the material receiving portion of the conveyor means for cooperation with the cams on the movable walls to pivot the movable walls to the material dumping position against the action of the springs.

29. The excavating and loading system according to claim 21 wherein the movable wall pivoting means further comprises: a cam track disposed around the axis of rotation of the buckets; and a plurality of cam followers each connected to one of the movable walls and each operatively engaged with the cam track for actuation thereby to pivot the movable walls between the material receiving and the material dumping positions.

30. The excavating and loading system according to claim 21 wherein the movable wall pivoting means comprises: a plurality of cylinders each connected to one of the movable walls for actuation under fluid pressure to pivot the movable walls to the material dumping position; and valve means for controlling the actuation of the cylinders in accordance with the rotational positioning of the digging buckets.

31. The excavating and loading system according to claim 21 further including: auxiliary conveyor means mounted on the vehicle for receiving excavated material from the conveyor means and mounted for pivotal movement about a vertical axis; a plurality of ballast tanks; and means for selectively directing liquid between the ballast tanks to counterbalance the weight of the auxiliary conveyor means.

32. The excavating and loading system according to claim 31 wherein the vehicle further comprises: a frame; means supporting the frame for movement along a surface; and an engine for actuating the supporting means to propel the vehicle and for actuating the conveyor means and the auxiliary conveyor means; and wherein the ballast tanks are further characterized by four ballast tanks positioned at forward and rearward positions on opposite sides of the frame.

33. The excavating and loading system according to claim 32 wherein the excavating wheel means is positioned at one end of the frame, wherein the conveyor means extends rearwardly from the frame between the ballast tanks, and wherein the auxiliary conveyor means is positioned at the opposite end of the frame from the excavating wheel means.

34. The excavating and loading system according to claim 21 wherein the conveyor means comprises a pair of cross conveyors mounted on the vehicle adjacent the excavating wheels for receiving material from the excavating wheels and for transporting the material inwardly and a conveyor centrally disposed on the vehicle for receiving material from the cross conveyors and from the excavating wheels and for transporting the material angularly upwardly to a discharge point at the opposite end of the vehicle from the excavating wheels.

35. An excavating and loading system comprising: an excavating wheel assembly comprising axle means and three rigid excavating wheels rotatably supported on the axle means, said excavating wheel assembly having a width at least equal to the widest portion of the remainder of the system; each of said excavating wheels including a plurality of digging buckets, each bucket having a cutting edge which extends to a stationary wall, and a wall mounted for pivotal movement from a material receiving position to a material dumping position; supporting and housing means extending between the excavating wheels and connected to the axle means for supporting the excavating wheel assembly; said three excavating wheels including a center excavating wheel comprising digging buckets spanning continuously between points immediately adjacent to the supporting and housing means and two side excavating wheels each comprising digging buckets spanning continuously from points immediately adjacent to the supporting and housing means to points defining the outer ends of the excavating wheel assembly; means including a drive mechanism extending through the supporting and housing means for rotating the excavating wheels so that the digging buckets follow a circular path; the axis of rotation of the excavating wheels being horizontally disposed and being angularly offset with respect to a line extending perpendicular to the longitudinal axis of the vehicle so as to prevent the formation of ridges in the spaces between the excavating wheels; means located within the margins of the excavating wheel assembly and responsive to rotation of the excavating wheels for positively pivoting the movable wall of each bucket of the excavating wheels to the material receiving position when the bucket is in the lower and forward portion of the path and for positively pivoting the movable wall to the material dumping position when the bucket is in the upper and rearward portion of the path; a vehicle for supporting and manipulating the excavating wheel supporting means and thereby positioning the excavating wheel assembly in engagement with material to be excavated; conveyor means mounted on the vehicle behind the excavating wheel assembly for movement around a course including a relatively low portion positioned to receive material from each digging bucket of the center excavating wheel upon the positioning of the movable wall of the bucket in the material dumping position and a relatively high material delivery portion located rearwardly of the vehicle from the lower portion; and means positioned on the vehicle behind the excavating wheel assembly to receive material from each digging bucket of the outside excavating wheels upon the positioning of the movable wall of the bucket in the material dumping position and for directing the material to the conveyor means.

36. The excavating and loading system according to claim 35 further including a conveyor frame supported on the main frame of the vehicle and extending angularly upwardly with respect thereto to define a course of the conveyor means, means supporting the upper portion of the conveyor frame for pivotal movement with respect to the lower portion thereof, an auxiliary conveyor supported at the rear end of the system for receiving material from the conveyor means, and means supporting the auxiliary conveyor for pivotal movement about a vertical axis.

37. The excavating and loading system according to claim 36 further including a ballast system comprising a plurality of tankS positioned at spaced points on the vehicle and means for selectively pumping liquid between the tanks and thereby counterbalancing the weight of the auxiliary conveyor.

38. The excavating and loading system according to claim 35 wherein the means for directing material from the two outside excavating wheels to the conveyor means includes cross conveyors for transporting excavated material inwardly to the conveyor means.

39. An excavating and loading system comprising: vehicle means having a main frame and adapted for movement over a surface and having a predetermined length and a predetermined width; excavating wheel means mounted at the front end of the vehicle means for rotation about an axis extending parallel to the width and perpendicular to the length of the vehicle; said excavating wheel means comprising axle means, two rigid side excavating wheels mounted cantilever on the axle means and comprising and outermost structural components of the excavating and loading system, a third rigid excavating wheel supported on the axle means and extending between the two side excavating wheels and spaced, parallel excavating wheel supporting and housing means extending between the center and the two side excavating wheels; means including a drive mechanism extending through the supporting and housing means for rotating and excavating wheels so that the digging buckets follow a circular path; the axis of rotation of the excavating wheels being horizontally disposed and being angularly offset with respect to a line extending perpendicular to the longitudinal axis of the vehicle so as to prevent the formation of ridges in the spaces between the excavating wheels; each of said excavating wheels further comprising a plurality of digging buckets with the digging buckets of the side excavating wheels spanning continuously from the outer ends of the excavating wheel means to points immediately adjacent the supporting and housing means and with the digging buckets of the center excavating wheel spanning continuously between points immediately adjacent the two supporting and housing means; the digging buckets each comprising a rear wall mounted for movement between a material receiving position and a material discharging position; means located within the margins of the excavating wheel means and responsive to rotation of the excavating wheel means relative to the vehicle for first positively actuating the movable wall of each digging bucket to the material receiving position and for subsequently positively actuating the movable wall of each digging bucket to the material discharging position; conveyor means mounted on the vehicle behind the excavating wheel means for receiving material from the center excavating wheel and for carrying the material upwardly and rearwardly to a discharge point at the rear end of the vehicle; and means mounted on the vehicle behind the excavating wheel means for receiving material from the two side excavating wheels and for directing the material to the conveyor means for transportation thereby to the discharge point.

40. An excavating and loading system comprising: an excavating wheel assembly comprising axle means and at least two rigid excavating wheels rotatably mounted cantilever on and supported on the axle means, said excavating wheel assembly having a width at least equal to the widest portion of the remainder of the system; each of said excavating wheels including a plurality of digging buckets located immediately adjacent one another to define the entire circumference of the excavating wheel, each bucket having a cutting edge which extends to a stationary wall, and a wall mounted for pivotal movement from a material receiving position to a material dumping position; supporting and housing means extending between the excavating wheels and connected to the axle means for supporting the excavating wheel assembly; each of said digging buckets extending continuously between a side wall thereof located immediately adjacent to the supporting means and a side wall thereof defining one end of the excavating wheel assembly; drive means extending through the supporting housing means for rotating the excavating wheels so that the digging buckets follow a circular path; means located within the margins of the excavating wheel assembly and responsive to rotation of the excavating wheels for positively pivoting the movable wall of each digging bucket of the excavating wheels to the material receiving position when the bucket is in the lower and forward portion of the path and for positively pivoting the movable wall to the material dumping position when the bucket is in the upper and rearward portion of the path; a vehicle for supporting and manipulating the excavating wheel supporting means and thereby positioning the excavating wheel assembly in engagement with material to be excavated; conveyor means mounted on the vehicle entirely behind the excavating wheel assembly for movement around a course including a relatively low portion positioned to receive material from the digging buckets of the excavating wheels upon the positioning of the movable walls of the buckets in the material dumping position and a relatively high material delivery portion located rearwardly on the vehicle from the low portion; and conical cutter means detachably secured to the two excavating wheels and extending in opposite directions therefrom for rotating with the excavating wheels under the action of the drive means.

41. An excavating and loading system comprising: an excavating wheel assembly comprising axle means and three rigid excavating wheels rotatably supported on the axle means, said excavating wheel assembly having a width at least equal to the widest portion of the remainder of the system; each of said excavating wheels including a plurality of digging buckets, each bucket having a cutting edge which extends to a stationary wall, and a wall mounted for pivotal movement from a material receiving position to a material dumping position; supporting and housing means extending between the excavating wheels and connected to the axle means for supporting the excavating wheel assembly; said three excavating wheels including a center excavating wheel comprising digging buckets spanning continuously between points immediately adjacent to the supporting and housing means and two side excavating wheels each comprising digging buckets spanning continuously from points immediately adjacent to the supporting and housing means to points defining the outer ends of the excavating wheel assembly; means including a drive mechanism extending through the supporting and housing means for rotating the excavating wheels so that the digging buckets follow a circular path; means located within the margins of the excavating wheel assembly and responsive to rotation of the excavating wheels for positively pivoting the movable wall of each bucket of the excavating wheels to the material receiving position when the bucket is in the lower and forward portion of the path and for positively pivoting the movable wall to the material dumping position when the bucket is in the upper and rearward portion of the path; a vehicle for supporting and manipulating the excavating wheel supporting means and thereby positioning the excavating wheel assembly in engagement with material to be excavated; conveyor means mounted on the vehicle behind the excavating wheel assembly for movement around a course including a relatively low portion positioned to receive material from each digging bucket of the center excavating wheel upon the positioning of the movable wall of the bucket in the material dumping position and a relatively high material delivery portion located rearwardly on the vehicle from the lower portion; means positioned on the vehicle behind the excavating wheel assembly to receive material from each digging bucket of the outsiDe excavating wheels upon the positioning of the movable wall of the bucket in the material dumping position and for directing the material to the conveyor means; and conical cutter means detachably secured to the outside two excavating wheels and extending in opposite directions therefrom for rotation with the excavating wheels under the action of the drive mechanism.

42. An excavating and loading system comprising: vehicle means having a main frame and adapted for movement over a surface and having a predetermined length and a predetermined width; excavating wheel means mounted at the front end of the vehicle means for rotation about an axis extending parallel to the width and perpendicular to the length of the vehicle; said excavating wheel means comprising axle means, two rigid side excavating wheels mounted cantilever on the axle means and comprising the outermost structural components of the excavating and loading system, a third rigid excavating wheel supported on the axle means and extending between the two side excavating wheels and spaced, parallel excavating wheel supporting and housing means extending between the center and the two side excavating wheels; means including a drive mechanism extending through the supporting and housing means for rotating the excavating wheels so that the digging buckets follow a circular path; each of said excavating wheels further comprising a plurality of digging buckets with the digging buckets of the side excavating wheels spanning continuously from the outer ends of the excavating wheel means to points immediately adjacent the supporting and housing means and with the digging buckets of the center excavating wheel spanning continuously between points immediately adjacent the two supporting and housing means; the digging buckets each comprising a rear wall mounted for movement between a material receiving position and a material discharging position. means located within the margins of the excavating wheel means and responsive to rotation of the excavating wheel means relative to the vehicle for first positively actuating the movable wall of each digging bucket to the material receiving position and for subsequently positively actuating the movable wall of each digging bucket to the material discharging position; conveyor means mounted on the vehicle behind the excavating wheel means for receiving material from the center excavating wheel and for carrying the material upwardly and rearwardly to a discharge point at the rear end of the vehicle; means mounted on the vehicle behind the excavating wheel means for receiving material from the two side excavating wheels and for directing the material to the conveyor means for transportation thereby to the discharge point; and conical cutter means detachably secured to the outside two excavating wheels and extending in opposite directions therefrom for rotation with the excavating wheels under the action of the drive mechanism.

43. An excavating and loading system comprising: an excavating wheel assembly comprising axle means and at least two rigid excavating wheels rotatably mounted cantilever on and supported on the axle means, said excavating wheel assembly having a width at least equal to the widest portion of the remainder of the system; each of said excavating wheels including a plurality of digging buckets located immediately adjacent one another to define the entire circumference of the excavating wheel, each bucket having a cutting edge which extends to a stationary wall, and a wall mounted for pivotal movement from a material receiving position to a material dumping position; supporting and housing means extending between the excavating wheels and connected to the axle means for supporting the excavating wheel assembly; said axle means comprising separate axle portions each rotatably supporting one of the excavating wheels and each detachably secured to the supporting and housing means; each Of said digging buckets extending continuously between a side wall thereof located immediately adjacent to the supporting means and a side wall thereof defining one end of the excavating wheel asssembly; drive means extending through the supporting and housing means for rotating the excavating wheels so that the digging buckets follow a circular path; means located within the margins of the excavating wheel assembly and responsive to rotation of the excavating wheels for positively pivoting the movable wall of each digging bucket of the excavating wheels to the material receiving position when the bucket is in the lower and forward portion of the path and for positively pivoting the movable wall to the material dumping position when the bucket is in the upper and rearward portion of the path; a vehicle for supporting and manipulating the excavating wheel supporting means and thereby positioning the excavating wheel assembly in engagement with material to be excavated; and conveyor means mounted on the vehicle entirely behind the excavating wheel assembly for movement around a course including a relatively low portion positioned to receive material from the digging buckets of the excavating wheels upon the positioning of the movable walls of the buckets in the material dumping position and a relatively high material delivery portion located rearwardly on the vehicle from the low portion.

44. An excavating and loading system comprising: an excavating wheel assembly comprising axle means and three rigid excavating wheels rotatably supported on the axle means, said excavating wheel assembly having a width at least equal to the widest portion of the remainder of the system; each of said excavating wheels including a plurality of digging buckets, each bucket having a cutting edge which extends to a stationary wall, and a wall mounted for pivotal movement from a material receiving position to a material dumping position; supporting and housing means extending between the excavating wheels and connected to the axle means for supporting the excavating wheel assembly; said axle means comprising separate axle portions each rotatably supporting one of the excavating wheels and each detachably secured to the supporting and housing means; said three excavating wheels including a center excavating wheel comprising digging buckets spanning continuously between points immediately adjacent to the supporting and housing means and two side excavating wheels each comprising digging buckets spanning continuously from points immediately adjacent to the supporting and housing means to points defining the outer ends of the excavating wheel assembly; means including a drive mechanism extending through the supporting and housing means for rotating the excavating wheels so that the digging buckets follow a circular path; means located within the margins of the excavating wheel assembly and responsive to rotation of the excavating wheels for postively pivoting the movable wall of each bucket of the excavating wheels to the material receiving position when the bucket is in the lower and forward portion of the path and for positively pivoting the movable wall to the material dumping postion when the bucket is in the upper and rearward portion of the path; a vehicle for supporting and manipulating the excavating wheel supporting means and thereby positioning the excavating wheel assembly in engagement with material to be excavated; conveyor means mounted on the vehicle behind the excavating wheel assembly for movement around a course including a relatively low portion positioned to receive material from each digging bucket of the center excavating wheel upon the positioning of the movable wall of the bucket in the material dumping position and a relatively high material delivery portion located rearwardly on the vehicle from the lower portion; and means positioned on the vehicle behind the excavating wheel assembly to receive material from each digging bucket of the outside excavating wheels upon the positioning of the movable wall of the bucket in the material dumping position and for directing the material to the conveyor means.

45. An excavating and loading system comprising: vehicle means having a main frame and adapted for movement over a surface and having a predetermined length and a predetermined width; excavating wheel means mounted at the front end of the vehicle means for rotation about an axis extending parallel to the width and perpendicular to the length of the vehicle; said excavating wheel means comprising axle means, two rigid side excavating wheels mounted cantilever on the axle means and comprising the outermost structural components of the excavating and loading system, a third rigid excavating wheel supported on the axle means and extending between the two side excavating wheels and spaced, parallel excavating wheel supporting and housing means extending between the center and the two side excavating wheels; said axle means comprising separate axle portions each rotatably supporting one of the excavating wheels and each detachably secured to the supporting and housing means; means including a drive mechanism extending through the supporting and housing means for rotating the excavating wheels so that the digging buckets follow a circular path; each of said excavating wheels further comprising a plurality of digging buckets with the digging buckets of the side excavating wheels spanning continuously from the outer ends of the excavating wheel means to points immediately adjacent the supporting and housing means and with the digging buckets of the center excavating wheel spanning continuously between points immediately adjacent the two supporting and housing means; the digging buckets each comprising a rear wall mounted for movement between a material receiving position and a material discharging position; means located within the margins of the excavating wheel means and responsive to rotation of the excavating wheel means relative to the vehicle for first positively actuating the movable wall of each digging bucket to the material receiving position and for subsequently positively actuating the movable wall of each digging bucket to the material discharging position; conveyor means mounted on the vehicle behind the excavating wheel means for receiving material from the center excavating wheel and for carrying the material upwardly and rearwardly to a discharge point at the rear end of the vehicle; and means mounted on the vehicle behind the excavating wheel means for receiving material from the two side excavating wheels and for directing the material to the conveyor means for transportation thereby to the discharge point.