WO1983004068A1

WO1983004068A1 - Reciprocably supported dual-drive member and features

Info

Publication number: WO1983004068A1
Application number: PCT/US1982/000688
Authority: WO
Inventors: William David Coski
Original assignee: William David Coski
Priority date: 1982-05-19
Filing date: 1982-05-19
Publication date: 1983-11-24
Also published as: EP0111477A1; AU8682082A

Abstract

The reciprocably supported member or tool (38) has its stroke adjustably located so that it can be used to drive its support (19), if desired, even while it is simultaneously impacting a work surface. Also, the member (38) may be carried on a conventional mobile carrier (300) as its support. The tool (38) will reciprocate away from the work surface, and work- or debris-removing apparatus (52) is provided in one embodiment. The drive for reciprocating the member may comprise a combustion engine (42), and the debris removal apparatus (52) may use the combustion gases of the engine (42) as a flush medium for the same. The tool (38) may be rotated in either direction while being reciprocated. The member may be used for horizontal or vertical impact drilling, pile driving, or merely propulsion.

Description

RECIPROCABLY SUPPORTED DUAL-DRIVE MEMBER AND FEATURES

Technical Field

This invention relates to a movably supported member which is reciprocable in relation to its support.

Stroke shifting means are combined with the member which are operable to determine the location of the member's stroke along the axis of reciprocation on the support.

Disclosure of Invention

There are various utilities for this combination. To illustrate, in certain embodiments of the invention, a tool is connected with the member and the member is operable to drive the tool in relation to a work object at a work station. Meanwhile, the stroke shifting means are operable to enable the member to move the support thereof relative to the object and/or the station. Also, in certain instances, the tool is rotatably carried on the member and there are means on the member whereby the tool can be rotated about the axis of reciprocation thereof while the member is reciprocating along the same. Preferably, the stroke shifting means are operable to shift the center of reciprocation of the member and/or provide a forward or rearward bias to the member as it reciprocates .

In its broadest form, one aspect of the invention relates to a movably supported large mass member which is reciprocable in relation to its support and has conjointly reciprocable drive means thereon for reciprocating the same. According to the invention, the drive means comprise a reci- procably engaged, piston-like element, propulsion means for reciprocating the piston-like element, and transmission means whereby the member is responsive to reciprocation of the piston-like element to undergo its own reciprocation

PI along a parallel to the axis of reciprocation of the piston¬ like element. The effective motion of the reciprocated large mass member is thus like the motion of a battering ra rather than a high-frequency percussive motion. Applica- tions for the large mass motion produced are drilling, pro¬ pelling, hammering, etc. The propulsion means for recipro¬ cating the piston-like element may be an internal-combustion engine or other engine forming an integral part of the large mass member or may be a completely external propulsion source, such as pressurized steam, hydraulic or pneumatic fluids, or mechanical crank mechanisms.

In many of the presently preferred embodiments of the invention, the member defines a chamber having the piston-like element reciprocably engaged therein to be reciprocated between opposite ends thereof. The drive means for the element include yieldable biasing means on one end portion of the chamber which are operable to displace the element in one direction of reciprocation thereof, and servo-displacement means on the other end portion of the chamber which are operable to intermittently displace the element against the bias of the yieldable biasing means. The transmission means include means on the respective end portions of the chamber which are operable, such as by com¬ pressing fluid therein, to convert the displacement of the piston-like element in the respective directions thereof into reciprocable motion on the part of the member in corre¬ sponding directions. For example, in certain embodiments, the one end portion of the chamber is closed and the servo- displacement means include means for alternately pressuriz- ing and depressurizing the other end portion of the chamber to displace the piston-like element against a fluid captive in the one end portion thereof. In some embodiments, the servo-displacement means include means for intermittently igniting a combustible charge in the other end portion of the chamber and means for exhausting the combustion gases from^' the same when the piston-like element is displaced as indicated. For example, in certain embodiments, the other end portion of the chamber is defined by a combustion engine having a port for exhausting the combustion gases from the same when the piston-like element is displaced as indicated, and means whereby a new combustible charge can be compressed in the other end portion of the chamber when the piston-like element is displaced by the bias of the captive fluid in the one end portion thereof.

The invention also relates to a movably supported member which is reciprocable in relation to its support and which has conjointly reciprocable drive means thereon for reciprocating the same, and means including a port in the body thereof whereby debris can be pneumatically flushed away from the region adjacent the relatively forward end of the member in one direction of the reciprocation thereof. In- one embodiment, the drive means comprise a combustion engine and the flush means include a connection between the engine and the port whereby the combustion gases can be conveyed to the port as the flush fluid for the debris.

In one embodiment, the movably supported tool, which is reciprocable in relation to its support, has a working head at one end of the axis of reciprocation there¬ of. The head has apertures in the outer peripheral edge of the working face thereof, and there are means interconnected with the head whereby a pressurized fluid can be discharged through one portion of the apertures into the region adja- cent the face of the head when the tool is generating debris from the work thereof. There are also means on the head which operatively define a relatively low-pressure zone at a point relatively rearward of the face, and means whereby another portion of the apertures are operatively inter- connected with the low-pressure zone so that the fluid can transport the debris away from the region at the face of the head to the low-pressure zone.

In some embodiments, the apertures in the head are disposed in the bottom portion of the head. For example, in certain embodiments, the tool is rotatably carried in a chuck which is reciprocably mounted in the support, and the fluid discharge means include valve means which are operable to prevent the fluid from communicating with the one portion

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O PI of the apertures during the upper portion of their field of rotation when the tool is rotated in the chuck.

In one embodiment, the apertures in the face of the head take the form of axially extending slots in the outer peripheral edge of the same which open into the annu- lus at the aforesaid opposing side of the head. In some embodiments, the slots are _^deeply radially inset in the body of the head. Moreover, the face of the head is conical and tapers relatively peripherally outwardly from the axis of the bit in the relatively rearward direction thereof. One portion of the apertures take the form of openings which are disposed in the face of the head intermediate the slots.

In many embodiments, the bit has percussive points on the working face thereof, and in some, the points are partially embedded in pads of abrasion-resistant material on the face.

In some embodiments, a tool is carried on the large mass member and the support for the same takes the form of a carriage which is supported on skids on the ground to slide over the surface thereof. The apparatus also com¬ prises means whereby the carriage can be slidably advanced along the surface of the ground when the tool is releasably engaged with the face of the earth in the one direction of reciprocation of the member. Also, the carriage has scoop- like means thereon which are disposed to receive the debris when the carriage is advanced in the one direction of reci¬ procation of the member and the pressurized fluid escapes from the aforesaid region through the face of the tool.

In certain embodiments, there are restraining means on the carriage which are frictionally engageable with

,the ground to provide a counterthrust for the member along the axis of reciprocation thereof. There are also means whereby the carriage can be slidably advanced within an opening in the face of the earth having surfaces on the opposing sides thereof which are obliquely angled to the horizontal of the earth, and means whereby the restraining means can be frictionally engaged with the aforesaid sur¬ faces to wedge the carriage therebetween as a component of the counterthrust. The invention also relates to a method for exca¬ vating a hole in the face of a tunnel site. According to the invention, a carriage is movably supported on the ground adjacent the face of the site and a percussive tool is mov- ably mounted on the carriage to be reciprocated in relation to the carriage and the ground. The tool is reciprocated in relation to the same to impact it on the face of the site and is rotated about the axis of reciprocation to bore a hole in the face. In one embodiment, the tool is releasably engaged with the carriage to move the carriage in relation to the ground while it is impacted on the face of the site. In this way, the tool advances the tool and carriage unit into the hole as it is deepened.

In certain embodiments, the carriage is friction- ally engaged with the ground to provide a counterthrust for the percussive action of the tool. However, the carriage is preferably supported on skids on the ground so that it can be trammed over the surface of the same, or the carrier can be a conventional tracked or wheeled vehicle.

Brief Description of the Drawings

These features will be better understood by refer¬ ence to the accompanying drawings wherein the invention is illustrated in terms of its application to a carriage- mounted tunnel excavating apparatus.

In the drawings,

FIGURE 1 is a perspective view of the apparatus when it is put in use in a tunneling operation;

FIGURE 2 is a side elevational view of the appara- tus in use;

FIGURE 3 is a front elevational view of the same;

FIGURE 4 is a top plan view of the same;

FIGURE 5 is a longitudinal cross-sectional view of the apparatus when the driven member of the apparatus is approaching the rearward limit of its stroke;

FIGURE 6 is a similar view of the apparatus when the driven member is at the forward limit of its stroke;

FIGURE 7 is a schematic representation of the apparatus when it is put to use in a tunneling operation^ FIGURE 8 is a schematic representation of th apparatus when it is put to use in a tunneling operation, but being retracted from the tunnel;

FIGURE 9 is a diagrammatic representat on of th two successive operations, starting with the neutral condi tion of the apparatus;

FIGURE 10 is a diagrammatic illustration of simplified form of the invention illustrating the principle of operation of one aspect; and FIGURE 11 is similar to FIGURE 10 but illustrates the principles on a conventional mobile carriage.

Best Mode for Carrying Out the Invention

Referring to the drawings, it will be seen that the apparatus 18 is mounted on a carriage 19 which comprises a tubular frame 2 that is supported on three skid-mounted struts 4 and 6. The more forward strut 4 is a rigid bibb¬ like extension of the frame and has a partly cylindrical shoe 8 at the bottom thereof to form a scoop. The bottom of the shoe is equipped with a pair of pad-like skids 9. See Figure 2 in particular. The more rearward struts 6 are pivotally adjustable, leg-like extensions of the frame and have pad-like skids 12 on the bottoms thereof which are interconnected with the frame by hydraulic cylinders 14 so that the struts 6 can be adjustably angled to the frame. Both pairs of skids 9 and 12 are slidably engaged with the ground 14 so that the carriage can be ^•"trammed" over the surface thereof, either in the direction of the working face 16 of the tunnel or in the opposite direction, relatively away therefrom.

The apparatus 18 is _^telescopically engaged in the axial bore 20 of the frame 2 and comprises a combination chuck and drive transmission sleeve 22 which is slidably engaged in the frame so that it can reciprocate along the axis 24 thereof but not rotate in relation to it. See the spline 26 which is interposed between circumferentially op¬ posing grooves 28 and 30 in the outer and inner peripheries of the sleeve and frame, respectively. Note also that the reciprocable motion of the sleeve is delimited by a pair of out-turned flanges 32 and 34 on the opposite ends thereof. These flanges operate to transmit driving forces into the carriage when it is desired to tram the same relative to the face of the tunnel, as shall be explained. They are actuat¬ ed and deactuated in this connection by a pair of conjointly operable control devices 36_^ on the carriage, as shall also be explained. The control devices are best seen in Figures 1 , 2, 4, 7 and 8. The tunneling operation itself is performed by a drill bit 38 which is carried on the sleeve 22 and assembled with the same so that it can be rotated about the axis 24 of the carriage while being reciprocated in unison with the sleeve. The reciprocable motion is generated by a drive mechanism 40 which is disposed on the rear end portion of the assembly 38,22. The drive mechanism is powered by a two-cycle diesel engine 42 which transmits the driving forces through a piston 44 in the assembly, as shall be explained. The bit 38 is rotated by a motor-driven chain and sprocket drive transmission 46 on the assembly. The motor of the same can be seen at 48.

When the apparatus 18 is put to use, the bit 38 generates excavated debris and the debris is flushed through the working face 50 of the bit in a manner to be explained. Meanwhile, the carriage is trammed toward the face 16 of the tunnel so that the debris tends to collect in the shoe 8 thereof. Also, the collected debris is continually removed by a conventional muck bucket-type collection device 52 which is rotatably mounted on a boss 54 at the forward end of the carriage frame. The device 52 rotates about the inner periphery of the shoe 8, scoops up the collected debris, and raises it onto a link-supported, vibrating trough conveyor 56 above the carriage. The debris is then discharged from the trough 58 of the conveyor onto a belt conveyor 60 adjacent the rear end of the apparatus.

The muck collection device 52 is rotated by a motor-driven ring gear transmission 62 mounted at the rear of the same between the boss 54 and the shoe 8. The mot of the same can be seen at 64. The conveyor 56 is vibrat by a motor-driven crank 66 which is interconnected with t trough 58 of the same by an articulated linkage 68. T motor for the crank can be seen at 70. The belt conveyor is rotated by a motor which -is not shown but which is co nected with one roller of the same to drive the belt abo the idler 74.

Now referring to the drawings in greater detail it will be seen that the bit 38 is conical at the worki face 50 of its head 76 and is slightly greater in diamet than the perimeter of the shoe 8. The body of its head i subdivided, however, by a series of symmetrically, angular spaced, deeply radially inset slots 78 at the outer periph eral edge 80 thereof. The slots 78 open into the back sid 82 of the head and divide the head into symmetrically, ang larly-spaced segments 84 that merge with one another at th flattened tip 86 thereof. Each of the segments 84 is cov ered by a replaceable pad 88 of studded, abrasive-resistan material which is adapted for drilling hard rock. The ti 86 is also covered by such a pad, but in this instance, th pad is rounded rather than flat. All of the pads are equip ped with a multiplicity of percussive studs 92 which ar embedded in the abrasive-resistant material to project fro the face of the bit at perpendiculars thereto.

At the back side 82 of its head, the bit is coni cally cha ferred at the edge 80 thereof and equipped with relatively reduced shank 94 that is sufficiently elongate to pass through the length of the sleeve 22. The body o the shank has a rearwardly oriented shoulder 96 thereo adjacent the head, and the inside edge of the shoulder i formed into a cylindrical neck 98. The neck is followed, i turn, by an annular groove 100 which is disposed about th midsection of the body and terminates at the tail 102 of th shank. The tail 102 is cylindrical and somewhat reduced i diameter relative to the neck 98, and the groove 00 taper inwardly toward the same in the rearward direction of th shank. The tail is also equipped with an annular groove 10 of considerably narrower width than the groove 100. The bit 38 also has a series of ports 106 in the head thereof which are symmetrically, angularly arrayed about the face of the head to open through opposing aper¬ tures 108 in the outer peripheral portions of the pads 88 thereon. The ports are serviced by a corresponding series of circumferentially spaced ports 110 in the neck 98 of the shank. The ports 110 open, into a corresponding series of passages 112. which extend forwardly through the neck to the head and then extend radially outward thereof to the ports 106.

The bit also has an axial bore 114 in the rear end 116 thereof. The bore extends forwardly through the length of the shank and into the head of the bit, where it termi¬ nates at a point short of the pad 90 on the tip of the same. The bottom of the bore (that is, the head end portion 118 thereof) is radially enlarged to assume a greater diameter than that of the main length of the bore.

Referring now to the sleeve 22, it will be seen that the axial opening 120 of the same has a stepped config- uration therein so that the sleeve can be rotatably inter- engaged with the neck 98 and the tail 102 of the bit when the shoulder 96 of the bit is abutted against the front end face 122 of the sleeve. The tail 102 projects beyond the rear end face 124 of the sleeve, however, as indicated, and to an extent that the groove 104 in the tail registers with the face 124. The stepped configuration includes a bore 126 which is countersunk in the forward end of the opening 120 and extends to a depth commensurate with the relatively for¬ ward end edge 132 of the groove 100. As seen, the larger bore 130 is sized to rotatably engage with the neck 98 of the bit, whereas the original opening 120 in the sleeve is sized to rotatably engage with the tail 102 of the same. Meanwhile, the smaller bore 126 defines an annular passage 134 at the interface between the sleeve and the midsection of the shank. The passage is cone-shaped in length and terminates at the forward end edge 132 of the groove 100 in the shank of the bit. However, the passage is operatively interconnected with the ports 110 in the neck of the bit by a partly annular circumferential groove 136 in the bottom of the sleeve 22, which is opposed to the shoulder 138 between the neck and the forward end edge 132 of the groove 100.

The sleeve 22 also has an inlet port 140 in the outer periphery thereof whereby fluid can be supplied to the ports 110 in the neck of the bit when the ports are rotating through the lower half of their field of rotation. The in¬ let port is disposed on the perimeter of the relatively rear end flange 34 of the sleeve and opens into a passage 142 in the body of the sleeve. The passage opens, in turn, into the bore 126 of the sleeve through a port 144 in the top thereof. The fluid may be supplied to the inlet port by an external supply system, such as a compressed air supply system (not shown), or it may be supplied to the inlet port by the diesel engine 42 of the drive mechanism 40 on the bit and sleeve assembly, as shall be explained shortly.

Referring to the right-hand side of Figures 5 and 6 in particular, it will be seen that the bit is assembled with the sleeve, and vice versa, by securing the sprocket 146 of the drive transmission 46 on the tail 102 of the same. The hub 148 of the sprocket is apertured and rabbeted to fit over the end of the tail. It is also sized so that the bit can rotate within the sleeve when the sleeve is interengaged between the hub and the shoulder 96 of the bit. Also, the rabbet in the hub 148 is countersunk at the for¬ ward end thereof to receive a thrust ring 150 which is interposed in the groove 104 of the bit across the joint between the hub and the sleeve. Cap screws 152 are employed to secure the sprocket to the bit, and the aperture 154 in the hub of the same is of such diameter as to freely pass the piston 44 of the reciprocable drive mechanism 40.

The engine 42 is enclosed within a two-part housing 156 which has a cap 158 for the sprocket 146 at the base thereof. The cap is affixed to the rear end 124 of the sleeve and has a partly annular, circumferential slot 160 in the top thereof through which the chain 162 of the drive transmission 46 is passed to the toothed perimeter 164 of the sprocket. It also has a central aperture 166 therein which corresponds in diameter to the bore 114 of the bit. The piston 44 is elongated and slidably engaged in the aper¬ ture 166 and the bore 114 to project within the interior of the housing components 168 and 170. The components, in turn, have a pair of axially aligned chambers 172 and 174 therein for the piston. The chamber 172 of the relatively rearward component 168 is adapted to slidably receive the body of the piston, whereas the chamber 174 of the rela¬ tively forward component 170 is adapted to slidably receive an annular flange 176 on the rear portion of the same. The flange and the front portion of the relatively forward cham¬ ber 174 serve as a pump for the fresh air supply to the engine, while the head end portion 178 of the relatively rearward chamber 172 serves as the combustion chamber there- of. The surrounding wall 180 and head 182 of the combustion chamber 178 are liquid cooled, and a nozzle 184 is installed in the head 182 of the same for the injection of fuel into the chamber. The fuel is intermixed with the fresh air, and the mixture is ignited in a conventional manner. The start- up ignition means are not shown, for the sake of simplicity.- A plurality of seal rings 186 are recessed about the rear end portion of the piston.

The relatively forward chamber 174 has an inlet port 188 in the wall thereof through which the fresh air is taken in by the pump. The inlet port has a check valve 190 across the same to allow the air to enter the chamber when the pump creates a pressure differential across the valve in the direction inwardly of the chamber, but to prevent airflow in the opposite direction when the pump creates a reverse differential thereacross. The incoming air is cleansed by an air filter 192 at the inlet 194 of the valve and is displaced from the chamber 174 through an outlet port 196 in the wall thereof, diametrically opposed to the inlet port 188. The outlet port is interconnected with a third port 198 in the forward end of the combustion chamber 178 by a duct 200 on the outside of the housing 156. The third port is diametrically opposed, in turn, by an exhaust port 202 on the opposite side of the combustion chamber at the

O PI forward end thereof. The exhaust port is connected, in turn, to the inlet port 140 of the sleeve 22 by a flexible hose 204 or the like, and the connection is valved so that the combustion gases can be selectively discharged to at os- phere, or to the port 140, depending on the stage in which the apparatus is being operated, as shall be explained.

Referring now to Figures 1 , 2, 4, 7 and 8 in particular, it will be seen that the carriage frame 2 has a pair of angularly spaced ears 206 upstanding thereon at the top thereof and that there is a pair of similarly upstanding ear-like extensions 208 on the rear end flange 34 of the sleeve. The respective extensions are axialy aligned with the ears of the carriage and are equipped with a pair of hydraulic cylinder- type servomotors 210 on the rear end faces thereof. Each servomotor has a piston-like control member 212 slidably engaged in the chamber 214 thereof, and each control member comprises a rod 216 having a pair of piston-like heads 218 and 220 on the opposite ends thereof. The rod is slidably guided in the respective extension 208 and the ear 260 thereopposite, and one head 48 of the same is slidably engaged in the chamber 214 of the respective servomotor, as indicated. The other head 220 is spaced outboard from the corresponding ear, and a pair of coiled springs 222 and 224 are caged about the rod between the ear 206 and the extension 208, on one hand, and between the ear and the outboard head 220 on the other. The springs operate to compensate for momentum lost by the bit and sleeve assem¬ bly 38, 2 when it is used in tramming the carriage and/or excavating the tunnel, as shall be explained; whereas the servomotors enable the effect of the springs to be altered for purposes of actuating and deactuating the tramming effect, as shall also be explained.

Referring now to Figures 1 , 2, 4, 5 and 6 in particular, it will be seen that the boss 54 on the forward end of the carriage frame 2 has an annular housing 226 thereabout which open^'s to the front of the apparatus. Also, there is a partly annular muck ring 228 connected upright about the front of the bibb-like strut 4 at a diameter intermediate that of the housing 226 and that of the shoe 8. A ball bearing ring 230 is seated on the boss at the mouth of the housing and is held in place by an annular bushing 232 which is secured to the forward end of the boss. The bushing registers with the inner race 234 of the bearing, and together with the same, forms a journal 235 for an annular disc 236 which is_^rotatably mounted on the outer race 238 of the bearing. The disc has a hub 240 and four lipped, side-loading muck buckets 242 symmetrically, angu- - larly arranged about the outer periphery thereof. The buck¬ ets are rotatably interengaged between the inner periphery of the shoe 8 and the muck ring to collect the debris on the bottom of the strut 4. The debris is then transported in conventional fashion to the terminal edge 244 of the muck ring at the top thereof. See Figure 1. The hub 240 has the gear 246 of the transmission 62 secured to the rear face

• thereof, and the gear is driven by a spur gear 248 on the motor 64 of the transmission. The motor is mounted within an aperture 250 in the strut 4. When the apparatus 18 is put to use, initially the piston 44 is put into motion by operating the servomotors 210 as double-acting cylinders or by pumping charges of com¬ pressed air into the head end portion 118 of the bore 114 in the bit. Either approach has the effect of generating rela- tive motion between the piston and the bit and sleeve assem¬ bly so as to enable the engine 42 to be started. Once the engine is running, successive fuel-air mixtures can be com¬ pressed and ignited in the combustion chamber 178 of the same to operate the engine in conventional fashion. More- over, each cycle of the engine displaces the piston forward¬ ly from the chamber, and the resulting forward motion of the piston operates to compress the air trapped in the head end portion 118 of the bore 114, as well as to compress the air ahead of the piston flange 176 in the pump chamber 174. The latter effect operates to force a new fresh air charge into the combustion chamber through the duct-connected ports 196 and 198. The new charge floods the chamber, and in doing so, displaces the residual combustion gases through the

-SΠCE

OMPI exhaust port 202. Meanwhile, the trapped air in the hea end portion 118 of the bore 114 operates as a yieldabl biasing medium; and when the accumulated pressure of th same overcomes the motion of the piston, the piston is reversed and driven in the opposite or rearward direction o the bore. As the piston returns to the combustion chamber, the flange 176 on the same opens the ports 188 and 196 and generates a suction condition in the pump chamber 174. This opens the valve 190, and a new charge of air is taken in through the inlet 194 of the same. The piston is then re- displaced in the forward direction of the bore by the igni¬ tion of a new fuel-air charge in the combustion chamber, and the operation is repeated again and again to cause the piston to reciprocate within the bit and sleeve assembly. As the piston reciprocates, it generates the same motion in the assembly 38,22 itself, inasmuch as the piston alternately compresses the air masses at the forward and rearward ends 118 and 178, respectively, of the assembly. The dynamics of the resulting motion on the part of the assembly are controlled in part by a throttle on the engine, which, for the sake of simplicity, is not shown- However, the useful application of these dynamics is determined more by the effect of the control devices 36, which, as explained, are interposed between the carriage and the reciprocating assembly.

Referring now to Figures 1, 2 and 4-9 in particu lar, it will be seen that when the engine is under, way, the stroke of the bit and sleeve assembly works against the bias of the respective pairs of springs 222 and ^'224 in the de- vices 36. This being the case, the energy stored in each spring pair operates _^to effectively restore any momentum lost by the assembly as it reciprocates counter thereto. In addition, the relative biases of the respective spring pairs operate to locate the stroke of the assembly along the axis 24 of the carriage. That is, the net differential between the biases determines where the stroke can take place on the axis; and this being the case, it is also true that the net differential can be used to relocate the stroke, that is, to

3

O shift it to a new location on the axis without diminishing or enlarging the length of the same.

The servomotors 210 are operated to vary the differential for this purpose, particularly in the sense of either locating the stroke of the assembly so that the flanges 32 and 34 of the same clear the stops constituted by the forward and rear end faces 252 and 254 of the carriage frame 2, or shifting the stroke so that one or the other of the flanges engages the corresponding stop on the carriage frame. The servomotors may be operated to reciprocate the assembly in relation to the carriage and the ground 14 with¬ out engaging the work face 16 of the tunnel. In such a case, the assembly can be said to be undergoing lost motion with respect to both the carriage and its support, i.e., the ground. Alternatively, they may be operated to reciprocate the assembly in engagement with the face of the tunnel while it is undergoing lost motion with respect to the carriage. In such a case, they are being used simply to enable the assembly to drive the tool constituted by the bit 38 without advancing (or retracting) the carriage at the same time. To advance the support in one embodiment, it is necessary to operate the servomotors in the sense of reciprocating the assembly in engagement with both the carriage and the face of the tunnel, either simultaneously or alterna ively, or both. Of course, the control devices 36 provide this capa¬ bility since they can vary the stroke of the assembly to drive the carriage alone or they can vary the stroke of the assembly to drive both the carriage and the bit.

In the case where the large mass member carries a tool and is on a conventional mobile carrier, the servo¬ motors will advance the tool into the work surface as the work surface face gets impacted away, thus allowing the carrier to be advanced only intermittently.

Referring now to Figures 7-9, and to Figure 9 in particular, it will be seen that these possibilities are schematically and diagrammatically illustrated in terms of a typical rock drilling operation. Initially, at the left- hand side of the diagram .in Figure 9 , the springs 222 and 224 of the control devices 36 are balanced and the apparatus is standing off from the rock face 256 of the tunnel at such distance that the bit and sleeve assembly can achieve no im¬ pact on either the face 256 or the carriage 2. This is the neutral condition of the assembly in that it is undergoing lost motion with respect to the ground, the face and the carriage. However, moving to the right on the diagram, it will be seen that the servomotors 210 can be operated to cause the outboard heads 220 of the control members 212 to compress the front springs 224 of the devices to the point where the rear end flange 34 of the assembly will impact the carriage at the rear end stop 254 thereof and cause the car¬ riage to tram forward toward the rock face. Subsequently, as the bit 38 approaches the face, the engine 42 can be throttled to give it more power and the compression on the springs 224 can be increased to compensate for the impact of the bit on the face. Meanwhile, the assembly can continue to impact the carriage for purposes of advancing it into the face as the drilling operation proceeds therein. The ad- vance of the bit is schematically indicated at 258, whereas the corresponding carriage advance is indicated at 260. Should it become necessary or desirable to reverse the direction of the carriage, such as to retract it from the tunnel, the servomotors 210 can be operated to release the front springs 224 to the point where the springs 222 and 224 are unbalanced in the opposite direction and the front end flange 32 of the assembly is caused to impact the carriage and produce reverse tramming of the same away from the rock face. When the apparatus 18 is at the rock face, the motor 48 is normally operated to rotate the bit. Also, the motors 64 and 70 are actuated, and the connection 204 be¬ tween the exhaust port 202 of the engine and the inlet port 140 of the sleeve is opened to discharge the combustion gases through the ports 106 in the head of the bit as the ports rotate through the bottom half of their field of rota¬ tion. The timing is such that the "pulses" of combustion gas discharge through the ports when the face of the bit is reciprocating in the direction relatively away from the face of the tunnel. As a consequence, the discharged gases enter the region between the faces when there is a gap 262 opened to them, and once in the gap, they effectively fluidize and entrain the excavated debris at the toe of the gap and then escape back through the slots 78 in the bottom half of the bit to remove the debris frpm the gap. Moreover, when the face of the bit is reciprocated in the opposite direction on the next stroke of the bit, i.e., toward the face of the tunnel, the gases in the gap are "pumped'- and recompressed by the face of the bit in the manner of a bellows to main¬ tain the flow of debris through the slots of the bit. Mean¬ while, the displaced debris enters the relatively low-pres¬ sure annulus 264 behind the head of the bit and deposits on the inner periphery of the shoe 8, where it is promptly removed by the buckets 242 of the muck collection device rotating therewithin. The continual forward movement of the shoe also lends itself to this effect, in much the same manner as one must continually "scoop" a dustpan forward when it is used in cooperation with a whisk broom if one is to achieve the maximum effect on the part of the broom.

Each bucket of the muck collection device lifts a portion of the debris upward about the muck ring 228 until the debris encounters the terminal edge 244 of the same at the top thereof. At this point, the debris tumbles onto the trough 58 of the vibrating conveyor 56 and is thereafter os¬ cillated rearwardly of the same until it ultimately tumbles onto the belt conveyor 60 for removal from the tunnel site. Ordinarily, the pulses of combustion gases are timed so that the back pressure at the face of the tunnel is at a minimum and the size of the gap 262 is such that the larger particles in the debris are able to escape through the slots without being ground against the face of the tunnel beforehand. In many operations, a steady flow of pressurized fluid is more desirable, and in such a case, a compressed air supply is commonly used in lieu of the illustrated engine hookup. Also, an airflow is commonly employed where

- TJRE

OM the combustion gases will pose an excessive pollution prob¬ lem, such as where the gases cannot be readily exhausted from the tunnel site during the tunneling operation.

In addition to serving as skids on which the carriage can be trammed over the surface of the ground, the pads 9 on the bottom of the shoe 8 also function as re¬ straining means with which,to provide a counterthrust for the bit along the axis of reciprocation thereof. Moreover, referring again to Figure 2, it will be seen that the pads 9 are not only symmetrically disposed on the outer peripheral surface of the shoe, but they are spaced apart from one another at acute angles to the vertical plane of the axis of reciprocation of the bit. As a consequence, the pads are frictionally engageable with the rounded but generally obliquely angled sidewall surfaces on the opposing sides of the trench-like bottom portion of the tunnel, and in this disposition, generate substantial, oppositely directed, horizontal components in their bearing forces, which, in turn, generate a wedge effect between the surfaces as a major component of the counterthrust. In theory, the maxi¬ mum wedge effect can be achieved by placing the pads near the horizontal plane of the axis. However, in practice, the pads are arranged somewhat below this plane, yet at suffi¬ cient height to generate enough wedge effect to counter the maximum thrust anticipated for the particular sleeve and bit assembly to be carried by each carriage; and the disposition and number of skids are varied from one carriage to the next as is necessary to vary the horizontal and vertical compo¬ nents of the bearing forces for this purpose. While the embodiment illustrated shows a full tunnel face impacting application for the invention, it should be understood that a conventional mobile carrier 300 (Figure 11) can also be employed. In this application, the large mass member 310 may be made smaller to be supported on a positionable support 320 which can be positioned by an arm and angled by an actuator 340.

The device can also be used for vertical pile driving or a variety of other applications requiring large mass impacting.

Claims

1. In combination, a large mass, movably supported member reciprocably mounted in a support having reciprocable drive means thereon for reciprocating the large mass member, said drive means comprising a reciprocably driven piston-like element, means for reciprocating the piston-like element, and transmission means to cause fore and aft reciprocation of the large mass member responsive to such reciprocation of the piston-like element.

2. The combination according to claim 1 wherein the large mass member defines a chamber having the piston-like element reciprocably engaged therein to be reciprocated between opposite ends thereof, and the drive means for the piston-like element also including yieldable biasing means on one end por¬ tion of the chamber which are operable to displace the element in one direction of reciprocation thereof, and servo- isplace¬ ment means on the other end portion of the chamber which are operable to intermittently displace the piston-like element against the bias of the yieldable biasing means, and wherein the transmission means are on the respective end portions of the chamber which are operable to convert the displacement of the piston-like element in the respective directions thereof into reciprocable motion on the part of the large mass member in corresponding directions.

3. The combination according to claim 2 wherein the one end portion of the chamber is closed and the servo-displace¬ ment means include means for alternately pressurizing and de¬ pressurizing the other end portion of the chamber to displace the piston-like element against a fluid captive in the one end portion thereof.

4. The combination according to claim 2 wherein the servo-displacement means include means for intermittently igniting a combustible charge in the other end portion of the

OMPI chamber, and means for exhausting the combustion gases from the same when the piston-like element is displaced as indicated.

5. The combination of claim 1 , including means for shifting the location of the center of the reciprocating stroke of the large mass member axially relative to the support.

6. The combination of claim 5 wherein the support movably rests on the floor and wherein said means for shifting the stroke are operable to shift the stroke of the large mass member into engagement with the support for causing the recipro¬ cating large mass member to move the support along the floor.

7. The combination according to claim 6 wherein the support includes a pair of axially spaced flanges and wherein the stroke shifting means are operable to engage and disengage the large mass member with said flanges for moving the support in relation to the ground.

8. The combination according to claim 7 wherein the stroke shifting means include a yieldable biasing element which is interconnected between the large mass member and the support to apply a biasing force on the large mass member to move in one axial direction, and the stroke shifting means include a yield- ably biased control actuator which is interconnected between the large mass member and the support, and means for varying the bias force by the control actuator to adjust the amount and direction of the yieldable biasing force applied to the large mass member when the large mass member is reciprocated.

9. The combination of claim 1 wherein a tool is attached to the large mass member and including means for rotat¬ ing the tool while reciprocating the large mass member.

10. The combination of claim 1 wherein a tool is attached to the large mass member for impacting a work surface, and wherein said support includes a mobile carrier.

11. In combination, a reciprocating member which is reciprocable in relation to a support and which has conjointly reciprocable drive means thereon for reciprocating the member, said member carrying an impact tool and including a port whereby debris can be pneumatically flushed away from the region adja¬ cent the relatively forward end of the tool in one direction of the reciprocation thereof, said, drive means comprising a combus¬ tion engine and including a connection between the engine and the port whereby the combustion gases thereof can be conveyed to the port as the flush fluid for the debris, and wherein the tool is rotatably connected with the member, and including valve means which are operable to prevent the combustion gases from reaching the tool during a portion of the rotation of the tool.

12. In combination, a movably supported tool which is reciprocable in relation to its support and has a working head at one end of the axis of reciprocation thereof, said head hav¬ ing fluid apertures in the working face thereof which are dis¬ posed adjacent the outer peripheral edge of the same, and there being means interconnected with the head whereby a pressurized fluid can be discharged through the fluid apertures into the region adjacent the face of the head when the tool is generating debris from the work thereof, means on the head which operative¬ ly define a relatively low-pressure zone ^"at a point relatively rearward of the face, and debris apertures operatively inter¬ connected with the low-pressure zone so that the fluid from the fluid apertures ^"can transport the debris relatively awa'y from the face of the head through the debris apertures.

13. The combination according to claim 12 wherein the tool is rotatably carried in a chuck which is reciprocably mounted in the support, and the fluid discharge means include valve means which are operable to prevent the fluid from commu¬ nicating with the fluid apertures during the upper portion of their field of rotation when the tool^' is rotated in the chuck.

14. The combination according to claim 12 wherein the face of the head is conical and tapers relatively peripherally outwardly from the axis of the bit in the. relatively rearward direction.

15. In combination, a reciprocably supported tool which generates debris in the tooling action thereof and which has a movably mounted debris collecting scoop on the support thereof, there being operatively engageable abutment means on the tool and the scoop, and control means whereby the abutment means can be releasably engaged with one another to move the scoop into debris collecting relationship with the tool.

16. The combination according to claim 15 wherein the tool is reciprocably mounted on a carriage and the carriage is mounted on skids on the ground, and wherein the skids are slid¬ ably engaged with the ground and the scoop is supported on one or more of the skids.

17. The combination according to claim 15, further comprising means which are operable to flush the debris into the scoop when it is in debris collecting relationship with the tool.

18. The combination according to claim 15, further comprising means which are operatively engageable with the scoop to remove the collected debris therefrom from time to time.

19. A method for excavating a hole in the face of a tunnel site, comprising movably supporting a carriage on the ground adjacent the face of the site, movably mounting a percus¬ sive tool on the carriage to be reciprocated in relation to the carriage and the ground, reciprocating the tool in relation to the carriage and the ground to impact the tool on the face of the site, rotating the tool about the axis of reciprocation to bore a hole in the face, and releasably engaging the tool with the carriage to move the carriage in relation to the ground while the tool is impacted on the face of the site.

"-^" CRE

20. The method according to claim 19 wherein the carriage is frictionally engaged with the ground to provide a counterthrust for the percussive action of the tool.

21. In an earth excavating apparatus, a member which is movably supported to be reciprocated in relation to its sup¬ port and has a conjointly reciprocable excavating tool connected therewith, the working face of which is releasably engageable with the face of the earth in one direction of reciprocation of the member to excavate a portion of the same, means whereby a pressurized fluid can be discharged into the region between the working face of the tool and the face of the earth to fluidize the excavated debris, control means whereby the pressurized fluid can be discharged into said region when the face of the tool is reciprocating in the other direction of reciprocation of the member, and means whereby the pressurized fluid can escape from said region through the face of the tool to remove the debris from the same in the aforesaid other direction of reci¬ procation of the member.

22. The earth excavating apparatus according to claim 21 wherein the fluid discharge means include a device which is operable to generate spaced pulses of pressurized fluid, and the control means include a connection between the device and the tool whereby the pulses are discharged into the aforesaid region when the face of the tool is reciprocated in the other direction of reciprocation of the member.

23. The earth excavating apparatus according to claim 21 wherein the fluid discharge means include drive means for reciprocating the member in relation to its support.

24. The earth excavating apparatus according to claim 23 wherein the drive means include a combustion engine, the exhaust port of which is connected with the face of the tool to discharge the combustion gases into the aforesaid region.

OMPI

25. The earth excavating apparatus according to claim 24 wherein the engine is carried on the member and is conjointly reciprocable therewith.

26. The earth excavating apparatus according to claim 21 wherein the fluid discharge means include apertures in the face of the tool which open in-ςo the aforesaid region between the face of the tool and the face of the earth.

27. The earth excavating apparatus according to claim 21 wherein the fluid escape means include apertures in the face of the tool which open into a relatively low-pressure zone on the opposite side of the tool from the working face thereof.

28. The earth excavating apparatus according to claim 21 wherein the tool is mounted to be reciprocated along a gen¬ erally horizontal axis and there are means for preventing the discharge of fluid into the aforesaid region in the relatively upper portion of the face of the tool.

29. The earth excavating apparatus according to claim 21 wherein the tool is carried on the member, and the support for the same takes the form of a carriage which is supported on skids on the ground to slide over the surface thereof, and wherein the apparatus also comprises means whereby the carriage can be slidably advanced along the surface of the ground when the tool is releasably engaged with the face of the earth in one direction of reciprocation of the member.

30. The earth excavating apparatus according to claim 29 wherein the carriage has scoop-like means thereon which are disposed to receive the debris when the carriage is advanced in the one direction of reciprocation of the member and pressurized fluid escapes from the aforesaid region through the face of the tool.

31. The earth excavating apparatus according to claim 29 wherein there are restraining means on the carriage which are frictionally engageable wi th th e ground to prov ide a co unter¬ thrust for the member along the axis of reciprocation thereof .

32. Drilling apparatus having a tool with a head for impacting against a work surface to be removed , said head having a forward drilling face , and means for reciprocat ing the tool along a substant ially hori zontal ax is for impacting the work surface , said reciprocating means moving the face of the head with each stroke a substantial distance away from the work sur¬ face so that a clearance gap is created between the work surface and the face during each stroke for removal of material broken from the work surface.

33. The drilling apparatus of claim 32 , fluid aper¬ tures around the drilling face for introducing pressurized fluid into said gap , debris apertures around the drilling face extend¬ ing through the head to pass debris rearwardly of the head , and including means for limiting passage of fluid through the fluid apertures only to the lower half of the drill ing face , whereby large pieces of debris can fall into said gap and be cleared through said debris apertures .

34. In combination , a carriage wh ich is supported on skids on the ground to slide over the surface thereof and has a tool reciprocably mounted thereon to be engaged with a work obj ect on the ground , res training means on the carriage which are frictionally engageable with the ground to provide a coun¬ terthrust for the tool along the axis of reciprocation thereof , means whereby the carriage can be sl idably advanced wi th in an opening in the obj ect having surfaces on the opposing sid es thereof which are obl iquely angled to the hori zontal of th e earth, and means whereby the restraining means can be fri ction¬ ally engaged with the aforesaid surfaces to wedge the carriage therebetween as a component of the counterthrust .

35. The combination according to claim 34 where in the carriage advancing means are operable to advance the carriage within a tunnel-l ike openi ng in th e face of the earth having relatively obliquely angled surfaces in the bottom porti thereof.

36. The combination according to claim 34 wherein th carriage advancing means include means for excavating a tunnel like opening in the face of the earth, and means for advanci the carriage within the opening, as it is excavated.

37. The combination according to claim 34 wherein th carriage has a partly cylindrical shoe thereon and the restrai ing means includes spaced restraining elements which are symme rically disposed on the outer peripheral surface of the shoe t engage the ground.

38. The combination according to claim 37 wherein th restraining elements take the form of pad-like skids which ar spaced apart from one another on the surface of the shoe a acute angles to the vertical plane of the axis of reciprocatio of the tool.

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