US2242472A - Snow plow - Google Patents

Description

May 20, 1941; R. w. KEEl-ER' SNOW PLOW Filed June 23, 1938 7 Sheets-Sheet 1 Q E L E E W D N O W 2 A Q May 20, 1941. R. w. KEELER SNOW PLOW Filed June 23, 1958 7 Sheets-Sheet 2 QAYMOND W. KEELEE.

y 1941- R. w. KEELER SNOW PLOW Fil'ed June 23, 1938 7 Sheets-Sheet 3 [NI/ENTO/Q,

QAYMQND W. KEELEIZ, DY Q MM. 721. M

ATTY

May 20, 1941.

R. W. KEELER SNOW PLOW Filed June 23, 1938 7 sheefi-sheet 5 May 20, 1941.

- R. W. KEELER SNOW PLOW Filed June 23, 1938 7 Sheets-Sheet 6 May 20, 1941. R. w. KEELER SNOW PLOW I Filed June 23, 1938 '7 Sheets-Sheet 7.

[NI/ENTOP} PAYMOND W; KEELEQ,

Patented May 20, 1941 UNITED STATES PATENT OFFICE SNOW PLOW Raymond W. Keeicr, Gallon, Ohio, asslgnor to The Galion Iron Works & Manufacturing Company, a corporation of Ohio Application June 23, 1938, Serial No. 215,440

10 Claims.

This invention relates to a new and improved type of snow plow or similar equipment in which the plow or blade is positioned in front of a tractor to remove snow or to grade a road.

An object of the invention is to provide an improved snow plow construction which is operated by a tractor in which there are power operated means comprising hydraulically controlled means for adjusting the position of the snow plow.

Another object of the invention is to provide an improved control means for a snow plow including a hydraulic system, the pump of which may be selectively connected to be driven from or disconnected from the motor of the tractor associated with the snow plow.

Still another object of the invention is to provide a snow plow attachment to a tractor and means for readily adjusting the position of the snow plow from the operator's position of the tractor.

A further object of the invention is to provide improved and rugged snow plow supporting and operating means which provide for very flexible control of the snow plow while at the same time providing a simple and eificient construction.

Other objects of the invention will appear hereinafter, the novel features and combinations being set forth in the appended claims.

In the accompanying drawings,

Figs. 1 and 2 combine to make a side elevational view of the apparatus comprising my invention, Fig. 2 being an extension along the line 2-2 of Fig. 1;

Fig. 3 is a side elevational view of the mechanism of Figs. 1 and 2 shown detached from the tractor;

Fig. 4 is a plan view of the apparatus of Fig. 3 after the hydraulic control system generally has been removed;

Fig. 5 is an enlarged detail view of a portion of the supplemental frame comprising the attachment which connects the snow plow and the tractor;

Fig. 6 is an enlarged end elevational view showing the method of mounting the rear end of the main attaching frame to the tractor;

Fig. 7 is a longitudinal sectional elevational view showing the drive means for the tractor and particularly a gear which is employed to drive the pump of the hydraulic system;

Fig. 8 is a transverse sectional elevational view taken substantially on the line 88 of Fig. 7 and enlarged, looking in the direction of the arrows;

Fig. 9 is a sectional plan view taken on the line 99 of Fig. 8 looking in the direction of the arrows; t

Fig. 10 is a plan view of the control valve of the hydraulic system and the operating mechanism therefor, the operating handle being broken away;

Fig. 11 is a longitudinal sectional elevational view taken on the line H-ll of Fig. 10 looking in the direction of the arrows;

Fig. 12 is a transverse sectional elevational view taken on the line I2--l2 of Fig. 10 looking in the direction of the arrows;

Figs. 13, 14, 15 and 16 are diagrammatic representations of the hydraulic control system showing four operating conditions encountered in actual practice, Fig. 13 being the no-load condition of the system, Fig. 14 being the condition when the snow plow is being lowered, Fig. 15 being the condition when the snow plow is being raised, and Fig. 16 being the condition when the hydraulic piston motor has reached one extreme position of expansion;

Fig. 17 is a plan view 'of a modified form of supplemental frame for supporting and attaching the snow plow to the main frame; and

Fig. 18 is a side elevational view of the mechanism of Fig. 17.

Referring particularly to Figs. 1 to 5, inclusive, of the drawings, it will be seen that my invention comprises a tractor 20 which is essentially a commercial form of tractor having a self-contained unitary tractor frame 2| which is formed as a unit with the rear axle housing, gear housing and crank case of the tractor motor, which is carried under the hood 22. The tractor is provided with the usual radiator 23, headlights 24, fuel tank 25, cab 26, seat 21 and steering wheel 28 which steers the front operating wheels 29 provided with pneumatic tires and carried upon front axle 30. Said tractor 20 also includes pneumatically tired ground engaging traction wheels 3| and a gear shift lever 32.

To provide for the attaching of a snow plow or other scraper blade to the tractor 20 so as to operate ahead thereof, I provide a main frame 33 comprising a pair of rearwardly positioned angularly extending angle members 34 which at their rear ends are provided with upwardly extending plates 35 each of which is adapted to be pivotally attached between a pair of downwardly extending lugs 36 by a pin 31 removably held in place by cotter keys 38, as shown in Fig. 6. The depending lugs 36 may be integral with the rear tractor axle housing 36' or they may be rigidly secured thereto by means of U-bolts.

Extending transversely between the angle members 34 is a cross-bar 39 having holes 46 at opposite ends thereof adapted to receive hang rods 4| (see Figs. 1 and 3) which are attached at their tops to brackets 42 secured to and carried by the body of the tractor 26. The hang rods 4| are provided with double locking'nuts 43 at each end to provide for adiustment of the effective length thereof. At their forward ends the angle members 34 are attached to a transverse angle member 44. The elements just described as part of the main frame 33 form the rear portion thereof which is pivotally attached to a front portion for pivotal movement about a horizontal longitudinally extending axis now to be described. 7

Said front portion of the main frame 33 comprises a pair of substantially longitudinally extending angle members 45 which are rigidly attached near their front ends to the axle 36 of the tractor 26 by U-bolts 46. At their rear ends the angl members 45 are attached to a transverse angle member 41 between which and the afore-described angle member 44 is positioned a spacer plate 46. A horizontally positioned longitudinally extending bolt 46 passes through the upright webs of the angle members 44 and 41 and through the plate 46 to provide the aforedescribed pivotal connection between the front and rear portions of the main frame 33. A helical spring 56 cooperates with appropriate wash- I ers and a nut on the bolt 49 to provide 9, iongitudinally extensible connection as well as a pivotal connection between the above mentioned parts of the main frame 33. Extending transversely of the angle members 45 near the rear ends thereof is an angl member 52 which is braced with respect to the angle members 45 by braces 53. The opposite ends of the angle member 52 carry brackets 54, 54 the function of which is described in complete detail hereinafter.

At their forward ends the angle members 45 carry a rigidly attached transversely extending angle member 55 which carries at opposite ends upstanding angles 56 (see Fig. 5). As seen by reference to Figs. 3 and 4 of the drawings, there extends upwardly from the angles 56 a pair of pivotally attached uprights 51, 51 formed of angle members and pivotally attached to said angles 56 by pivot pins one of which is seen at 56 in Fig. 3 of the drawings.. The tops of the uprights 51 are rigidly attached by a cross-piece 59 in the form of an angle member which is provided at opposite ends with brackets 66, 66'. Extending between the previously described brackets 54, 54 and the brackets 66, 66 are adjustable brace rods 6|, 6| provided at each end with adjusting yokes 62, 62 associated with which are appropriate lock nuts 62.

By reference to Fig. 1 of the drawings, it will be seen that the afore-described main frame 33 is positioned generally below the tractor 26 with the uprights 51 and cross-piece 59 positioned in front thereof with the brace rods 6| extending one on each side of the motor and tractor frame 2| of the tractor 26. Extending forwardly from and pivotally attached to the main frame 33 is an auxiliary frame 63 to the front end of which is attached a snow plow or scraper blade 64. The auxiliary frame 63 is constructed of a pair of similar heavy brackets or castings 65 the structure of which is best seen by reference to Fig. 5 of the drawings. Each of said castings 65 is formed with a main shank 66 which is pivotally attached to the lower portion of one of the aforementioned angle members 56 by a pivot pin 61 one end of which is carriedby said angle member 56 and the other end of which is ,carried by the forward extension 56 of th vertical flange of an angle 45 of the main frame 33. Appropriate removable cotter keys 66 are provided to maintain the pivot pin 61 in position.

Each of the castings 65 is bifurcated at its forward end to provide spaced arms 16 and 1| adapted to receive pivot pin 12 which extends between reinforcing ribs 13, 13 rigidly attached to and forming part of the snow plow 64. Appropriate cotter keys 14, 14 are provided to maintain the pivot pin 12 removably in place.

As clearly seen by reference to Fig. 4 of the drawings, a pair of cross rods 15 extend diagonally across and between the castings 65, 65 and rigidly attach them together thus insuring their pivotal movement substantially in unison, the rods being bolted or riveted together where they cross each other and the ends of the rods being bolted or riveted to the castings.

In addition to the pivotal connection above described between the auxiliary frame 63 and the snow plow 64, further resilient connecting means 16, 16 are provided to maintain th slope of the leading face of the snow plow or grader blade in any desired position. Said connecting means 16, 16 are of similar construction and each comprises a yoke 11 pivotally attached by a pin 16 to a bearing box 16 (Fig. 5) formed as an integral part of the main shank 66 of the casting 65, and a yoke 66 pivotally attached by a pin 6| to the afore-described ribs 13 of the snow plow 64, which yokes 11 and 66 are resiliently connected together by a through bolt 62 which extends through each and is provided with a pair of surrounding helical springs 63 and 64, the latter of which is interposed between the two yokes 11 and 66, and the former of which is interposed between a washer 62' at one end of the bolt 62 and the yoke 66. It will be evident that the connecting means 16 is designed to maintain the blade 65 of the snow plow 64 at a normal predetermined angle but that the snow plow is provided for limited resilient pivotal movement about the axis of the pivot pins 12 both in a clockwis and a counter-clockwise direction with respect to said normal position. This provides for the absorption of shocks received by the blade 65 in the operation of the snow plow 64 such as, for example, those received when a stone is struck on the road surface.

To provide for the pivotal adjustment of the auxiliary frame 63 with respect to the main frame 33 about the axis of the pivot pins 61, which is a substantially horizontal axis, with the consequent raising and lowering of the snow plow 64 or blade 85, I provide at each side of the auxiliary frame 63 a power operated adjusting mechanism which is preferably in the form of an expansible hydraulic piston motor 66, there being two such motors 66 of similar construction. The upper end of each of the cylinders 69 of the motors 66 is pivotally attached by a pin 61 to an upright 51 and a spaced vertical plate 66 rigidly attached to the angle member or cross-piece 56, said pin 61 being removably held in place by appropriate cotter keys.

The piston rod 96 of each motor 66 is provided with a flange 9| against which abuts a helical spring 92 which rides on a yoke 93, which piston rod 96 is provided with a further helical spring 94 cooperating with a large washer 65 carried at the lower end of the piston rod 90 to provide a resilient connection between said yoke 93 and said piston rod 90 for movement in reverse directions. That is, the two helical springs 92 and 94 provide for reverse movement of the piston rod 90 with respect to the yoke 93 resiliently in reverse directions. By reference to Fig. 5 of the drawings, it will be seen that the yoke 93 is pivotally attached by a pin 96 to a bearing box 91 formed integral with the arm H of the casting 65. It will thus be evident that the snow plow 64 is held in any adjusted position by the hydraulic piston motors 86, 8'6 but resilient movement from the normal position as determined by said motors 86, 86 is permitted in reverse directions due to said springs 92 and 94. The hydraulic piston motors 06 are very powerful and easily controllable power operated means for adjusting the position of the auxiliary frame 63 with respect to the main frame 33 about the horizontal axis provided by the pivot pins 61, thus providing for the ready adjustment of the snow plow 64. As hereinafter described in full detail, the motors 86 are locked in any position of adjustment to which they are adjusted thus preventing either expansion or contraction of them under the influence of the snow plow 64 when in operation.

By reference to Figs. 1 and 3 of the drawings, it will be seen that I have provided a. hydraulic system 98 to control the hydraulic piston motors 86, 86. Said hydraulic system comprises a hydraulic fluid tank or reservoir 99 which is preferably positioned along one side of the tractor 20 ahead of the cab 26 and is supported upon brackets I which extend from the tractor frame. Positioned on top of the reservoir 99 is a control valve IOI, hereinafter described in full detail, which is provided with an operating lever I02 located within easy reach of the tractor operator, as clearly seen by reference to Fig. 1 of the drawings. The operating lever I02 is spring biased to a normal or neutral position by spring means I03 which are operative to restore the control valve IOI to its normal or central position whenever the operating lever I02 is released. The fluid under pressure is derived from a pump I04 which is driven from the motor of the tractor 20 under the control of the operator, as now to be described.

By reference to Fig. 7 of the drawings, it will be seen that associated with the transmission I05 of the tractor is a wide gear I06 which is always in mesh with the driving gear I01 regardless of the position of said driving gear I01. By reference to Figs. 8 and 9 of the drawings, it will be seen that the wide ear I06 drives gear I08 keyed to pump shaft I09 through interme diate control gear II 0 which is shiftable by a shipper mechanism II I along the shaft I I2 either into or out of mesh with the wide gear I06. In Figs. 8 and 9 of the drawings, the driving relation between the gear I06 and the shaft I09 is illustrated. Associated with and operating the shipper III is a rock shaft II3 controlled by operating lever II4 which in turn is controlled pressure conduit II1 to the control valve IN. A return conduit "8 provides a return path from the control valve IN to the tank 99. Control conduits H9 and I20 extend from the control valve [M to opposite ends of the cylinders 89 of the hydraulic piston motors 66which are connected in parallel. Also extending from .the output of the pump I 04 to the tank 99 is a by-pass conduit I2I controlled by a high pressure relief valve I22. 7

It may be stated that the afore-described conduits II9, .I20'are preferably flexible fabricated rubberhoses capable of standing relatively high pressures which conduits'may be readily directed over tortuous paths to reach the hydraulic piston motors 86, while at the same time providing for relative adjustment between the'portions of the main frame 33, particularly between the uprights 51 and the angle members 45 as provided by the brace rods 6|. Appropriate brackets I23 are also provided to support the conduits II 9, I20 from the tractor frame (Fig. 1).

Before describing the operation of the hydraulic control system, attention is directed to Figs. 10, 11 and 12 of the drawings which illustrate the structure of the control valve I 0|. Said control valve comprises a main base I24 which is formed as an integral part of the tank 99 upon which is bolted a main body or casting I25 as by machine bolts I26. Extending longitudinally through the casting I25 is a cylindrical bore I21 one end of which communicates with a chamber I28 in communication with the conduit I I8 which is nothing more than a bore in the base I24 providing a return path to the tank 99.

Centrally of the bore I21 is a circumferentialchamber I29 which communicates with the pressure conduit II1. To the rear of the chamber I29 is a circumferential chamber I30 which communicates with the control conduit II9. In front of chamber I29 is a circumferential chamber I3I which communicates with the control conduit I20. Slidably mounted within the bore I21 is a slide piston I32 provided with a central bore I33 which communicates with the right hand end thereof, as viewed in Fig. 11 of the drawings, and which communicates with a circumferential groove I34 in said piston I32 by way of four radial ports I35. Rearwardly of the groove I34 is a relatively wide groove I36 and forwardly of the groove I34 is another relatively wide groove I31. A felt packing I38 is provided to prevent a flow of fluid from the control valve IOI, which packing is provided with appropriate drain conduits to the tank 99. As clearly seen by reference to Figs. 1, 3 and 10 of the drawings, an operating shaft I39 extends between the operating lever I02 and the slide piston I32.

The normal position of the control valve IOI is illustrated in Figsjll and 13 of the drawings, wherein a no-load by-pass is provided from the pressure conduit I II1 through chamber I29, groove I34, ports I35, bore I33, bore I21 and conduit II8 to the tank 99. This is the normal or non-operating position of the control valve IM and provides for no-load operation of the pump I04 by virtue ofthe afore-described low pressure day-pass. It is to be noted that at the same time the piston rod is locked in its position of adjustment by virtue of the fact that the control conduits H9 and I20 have hydraulic fluid trapped in them which cannot escape due to the fact that the chambers I30 and I3I are sealed by the grooves I36 and I31.

In Fig. 14 of the drawings, the piston I32 has sure conduit H1 is placed in communication with control conduit I20 by way of wide groove I31 and control conduit H9 is in communication with return conduit II8 by way of ports I35 and bore I33.

By reference to Figs. 13, 14 and 15 it will thus be evident that when the control valve IN is in its normal position to which it automatically returnswhen operating lever I02 is released, the

pump I04 will be operated under no-load by virtue of a no-load by-pass and the piston motor 86 will be sealed in any position to which it has been adjusted. By adjusting the control valve IOI by moving the piston I32 to the right, as viewed in Fig. 14, the no-load by-pass for the pump I04 will be automatically shut off and the piston motors 86 will be expanded. As illustrated in Fig. 15, when the control valve IOI is operated by moving the piston I 32 to the left from its normal position, the no-load by-pass will again be cut off and the hydraulic piston motors 06 will be contracted. It is thus manifest that the tractor operator need only operate the lever I02 to control the valve IOI to adjust the snow plow 64 either by raising or lowering it and when it is adjusted it will be held in adjusted position against both upward and downward movements except as provided by the afore-described resilient con nections.

In Fig. 16 of the drawings the position of the valve IN is the same as illustrated in Fig. 14, but

the piston of the illustrated hydraulic pistonmotor 86 has reached the end of its stroke. When such a condition is realized, the high pressure relief valve I22 will come into operation to provide a return path for the fluid delivered by the pump I04 by way of the high pressure by-pass I2I. This prevents any damage to the pump or any of the other elements of the hydraulic control system should the control valve IOI be maintained in an operating condition after the hydraulic piston motors 86 have been completely expanded.

The ,high pressure relief valve I22 will likewise operate to provide a by-pass should the hydraulic piston motors be completely contracted with the valve IOI maintained in an operating position, or should the hydraulic piston motors 86 attempt to move the snow plow 64 in either direction against a very rigid obstruction. In other words, the high pressure relief valve I22 is effective to relieve any abnormal pressure which may appear at the out-put of the pump I04 thereby preventing any damage to the hydraulic control system.

Attention is now directed to Figs. 17 and 18 of the drawings wherein there is illustrated a modified form. of auxiliary frame I,40 which may be substituted for the auxiliary frame 63, it being understood that all of the other structure disclosed in the other figures of the drawings have not been modified unless definitely indicated. In this connection, it may be stated that the auxiliary frame I40 may simply replace the auxiliary frame 63 with certain modifications of the snow plow and hydraulic piston motors, as hereinafter described 'in full detail.

Said auxiliary frame I40 comprises a rear part I formed by a pair of longitudinally extending downwardly sloping angle members I42 connected together by a transversely extending cross-angle I43. The rear ends of the angle members I42 are pivotally attached to the main frame 33 by the previously described means including the pivot pins 61 similar to the manner in which the castings 65 were attached thereto as disclosed in detail in Fig. 5 of the drawings and as above described.

Pivotally attached to said rear part I of the auxiliary frame I40 is a front part I44, the attachment being effected along a central horizontal longltudinal'axis by a pivot pin I provided with appropriate retaining cotter keys. This pivot pin I45 provides for relative movement of the front and rear parts I44 and I, about a horizontal longitudinally extending axis which is particu-'- larly desirable where the snow plow I46 is adjusted about a vertical axis, as hereinafter described in full detail, because whenever the front part I44 of the auxiliary frame I40 is in any position other than horizontal, a slight tilting movement about the axis of pin I45 is required to maintain the blade I41 of said snow plow I46 in a horizontal position. This will be explained in more complete detail hereinafter.

The front part I44 of said auxiliary frame I40 is formed by a pair of longitudinally extending angle members I48, the rear ends of which are connected by a transversely extending angle member I49 which receives the afore-described pivot pin I45. Extending diagonally from the angle members I48 at their forward ends is a pair of angle members I50 the inner ends of which are attached to a bearing plate I5I upon which is pivotally supported a cross-piece I52, the ends of which support a semi-circle I53 formed of an angle, which cross-piece I52 is pivotally supported upon the bearing plate I5I by a pivot bolt I54 thereby providing pivotal movement of the semi-circle I 53about the axis of said bolt I54. The semi-circle I53 is provided with a plurality of spaced apertures I55 adapted selectively to receive a pin I56 removably extending between a cross-piece I51, the ends of which are supported by the angles I48, and an angle member I50 which is rigidly attached to said cross-piece I51 as by welding.

As clearly seen by reference to Figs. 17 and 18 of the drawings, the horizontal flange of the semi-circle I53 slides between the cross-piece I51 and the horizontal flange of the angle member I58 thereby preventing vertical movement of said semi-circle I53 with respect to said angle member I58, but permitting free rotation of said semi-circle I53 about the axis of the pivot bolt I54. Itis, of course, evident'tha't the pin I56 locks the semi-circle I53 in any position of adjustments which can be varied in accordance with the accommodation of the apertures I55.

At each end the semi-circle I53 is provided with a horizontally disposed transversely aligned journal box I56 which carries a pivot pin I60 which extends between a pair of ribs IIiI on the rear face of the snow plow I46 and provides a pivotal connection between each end of said semicircle I53 and said snow plow I46.

To provide a further and resilient connection between the semi-circle I53 and the snow plow I46 I provide at each end of said semi-circle I53 an upwardly inclined bracket I62 provided with a through bolt I63 having appropriate adjusting and locking nuts I64 associated therewith and threading through a yoke I65 pivotally attached by a pivot pin I66 to the aforementioned ribs I6I of the snow plow I46. Reversely operable helical springs I61 and I68 are provided on opposite sides of the bottom of the yoke I65 to provide for resilient movement of the snow plow I46 about the axis of the two spaced apart pivot pins I60 as determined by the operating conditions encountered when the snow plow is in actual operation.

- As clearly seen by reference to Fig. 17 of the drawings, through bolt I63 is provided with a large washer I69 which cooperates with the spring I68. It is thus seen that the snow plow I46 is pivotally and resiliently supported by the semi-circle I53 which may be adjusted about the upright axis of the pivot bolt I54 to adjust the angle of attack of the snow plow I46 with respect to the direction of travel of the tractor.

It is manifest that if the frame I40 is adjusted on the pivots 61 to move the snow plow I46 from its position shown in Fig. 18 ,the pivot I54 will be moved to an inclined position. Now upon adjusting the snow plow from its transverse position shown in Fig. 1'7 on such inclined pivot I54 to a diagonal position relative to the path of travel of the machine one end of the cutting blade I41 will strike against the road surface while the other end will be elevated farther from the road surface. Consequently, if the adjustment of the cutting blade to such diagonal position is made while the pivot I54 is vertical and this is followed by operation of the motors 86 to swing the frame on the pivots 61, that end of the cutting blade farther away from the axis of the pivots 61 will be moved to a position at a higher elevation than the opposite end of the blade. This is because both ends of the blade are given the same angular movement on the axis of the pivots but the more remote end of the blade moves through a longer arc by reason of its movement on a longer radius.

In order to maintain the lower edge of the cutting blade I41 in a horizontal plane under such conditions, the front section I44 of the frame I40 is free to pivot about the longitudinally extending central axis of the pin I45.

When the motors 86 are operated to lift the frame I40 on the axis 61, they will operate equally since they are connected in parallel. While suspended above the road surface the snow plow may be adjusted manually from the transverse position shown in Fig. 17 to a position extending diagonal to the path of travel of the machine, and locked. Then that end of the cutting blade nearer the axis of the pivots 61 willbe in a relatively low position and the other end in a relatively high position. Now upon reversing the motors 86 to lower the snow plow the lower end will strike the road surface first and finally the other end will engage the road surface and front section I44 of the frame will be automatically tilted on the horizontal longitudinally extending pivot pin I45 to permit the lower edge of the cutting blade I41 to move to a horizontal plane. The motors 86 being connected in parallel will stop their expansions one after the other, that motor nearer the lower end of the blade stopping first. If the operator does not move the controlling valve to neutral position when both motors are automatically stopped by the resistance offered by the road surface to further downward movement of the blade, the high pressure relief valve may be set to automatically open the by-pass around the pump.

After the snow plow has been adjusted to its diagonal position and the lower edge of the cutting blade has'been adjusted to the level of the road surface the front section I44 of the frame I will remain in its adjusted tilted position on the pivot'pin I45 with the motors 86 expanded to different lengthsaccordingly. After such adjustments have been effected, the snow plow may be adjusted in elevation through a wide range because the motors are connected in parallel and operate equally so long as the upward and downward movements thereof do not meet with unequal obstructions to such movements and so long as the pistons of the motors do not either of them reach the limits of their strokes.

It may be stated that the hydraulic piston motors 86 illustrated in Figs. 17 and 18 are the same as those illustrated in other figures of the drawings, except for a small change in that the piston rods are somewhat longer than the piston rods 90 due to the slope of the rear part I 4|; and the yokes 93' differ from the yokes 93 previously described, in that said yokes 93 are built up from relatively heavy blocks I10 to which are bolted a pair of side plates "I. The side plates III of the yokes 93' are pivotally attached by pivot pins I12 to hearing boxes I13 carried upon outward extensions of the afore-described angle members I50. It is thus manifest that the hydraulic piston motors 86 may beoperated in the manner previously described in connection with Figs. 1 to 17 of the drawings, to adjust the auxiliary frame I40 about the axis of the pins 61 and thereby adjust the snow plow I46 upwardly and downwardly.

In the operation of the device comprising my invention, an operator can drive the tractor 20 along a roadway to remove snow or to'perform a grading or maintaining'operation while having complete control of the tractor and the snow plow' ahead of it, all from a single station. Adjustment of the snow plow upwardly and downwardly is very easily and readily effected by the operator simply by controlling the lever I02 in response to which very powerful power operating hydraulic control mechanism comes into play to adjust the snow plow or grader tool and to hold it resiliently in any position of adjustment.

In the form of the invention illustrated in Figs. 17 and 18 of the drawings, it is further possible to adjust the angle of attack of the snow plow or blade by pivoting it with respect to the axis of the pivot bolt I54 and locking it in any desired position of adjustment. At the same time, the pivotal connection I45 provides for the automatic compensation of differences in the normal elevation of the opposite ends of the blade I41 which are caused by the pivotal adjustment of the auxiliary frame I40 on the horizontal axis 61.

It is thus seen that a snow plow or grader mechanism has been provided as a complete unit which can be operated with a minimum of effort by a single operator on the tractor.

It should be particularly noted by reference to Figs. 17 and 18 that the reciprocable hydraulic motors 86, 86 are arranged in parallelism at the sides of the auxiliary frame I40 and are pivotally connected at their lower ends at I12, I12 to the forward frame section'i44 independently of the semi-circle I53. The piston rods 90', 90 are extended downwardly beyond the annular flanges 9|, 9| and through the blocks I10, I10 of the yokes or stirrups 93', 93'. The lower ends of these rod extensions are screw-threaded to receive nuts as illustrated in dotted lines in Fig. 18

and such nuts may be locked in adjusted positions.

The springs 92 and SI above and below the blocks I10 are preferably stiff and heavy so as to be sufliciently strong to co-operate with the hydraulic motors to form rather rigid extensible connections between the main and auxiliary frames adapted to be held at adjusted lengths by locking the pistons in the cylinders 86, 86. Consequently the nuts at the extreme lower ends of the piston rod extensions are not tightened sufflciently to place any initial tension in the springs 92 and 94, these nuts serving merely to hold the springs in place against the blocks I10. However, downward pressure on the scraper blade I" is yieldingly exerted through the springs 92 and lifting of the snow-plow assembly is yieldingly exerted through the springs 94.

It will also be seen by referring to Figs. 17 and 18 that the springs 92 and 94 will act as shock absorbers to cushion sudden up and down movements of the scraper assembly when passing over irregularities in the roadway while the hydraulic motors are locked at adjusted lengths. Main reliance for this purpose, however, may be had on the presence of the springs I61 and I68. When the blade I" strikes an obstruction the tilting of the snow plow I 46 on the axis I60 will be yieldingly resisted by the springs I68 and the recoil will be absorbed by the springs I61. Due to the presence of the stirrups I65 pivoted at their for-' ward ends to the back side of the snow plow and the co-relation between the cross-pieces of these stirrups and the springs I 61, I68, the front and rear sides of the brackets I62 serve as abutments for these springs when compressed by the successive rearward and forward tilting movements of the snow plow. Initially the nuts I64 merely hold the springs I61 and 168 in place against their end abutments.

Obviously those skilled in the art may make various changes in the details and arrangement of parts without departing from the spirit and scope of the invention as defined by the claims hereto appended, and I therefore wish not to be restricted to the precise construction herein disclosed.

The modification shown in Figs. 17 and 18 constitutes the subject matter claimed in my divisionalapplication S, N. 321,516.

Having thus described and shown an embodiment of my invention, what I desire to secure by letters Patent of the United States is:

1. In scraper apparatus, the combination with a main frame, of an auxiliary frame pivotally attached to the front thereof for adjustment, a scraper attached to the front of said auxiliary frame, said auxiliary frame comprising a pair of similar brackets bifurcated at one end with cross connecting means between the brackets, means pivotally attaching the bifurcated ends of said brackets to said scraper, means resiliently connecting each of said brackets to said scraper, and extensible means connecting one bifurcated arm of each bracket to said main frame.

2. In scraper apparatus, the combination with a blade, of a frame, means connecting said blade to the said frame, means pivotally supporting the rear of said frame for pivotal movement about a transverse axis, means for adjusting saidframe about said transverse axis to adjust said blade vertically, said frame comprising a pair of spaced castings each having a forward bifurcated end, one arm of each bifurcated end being attached both to said blade and to said adjusting means. i

3. As an article of manufacture, a frame member comprising a one-piece casting having a body bifurcated at one end to provide two arms, each-end having pivot holes therein there being aligned pivot holes in the ends of said two arms, and a pair of bearing boxes having pivot holes, one carried by the body proper and one by a bifurcated arm.

4. As an article of manufacture, a one-piece frame member having a body bifurcated at one end to provide two arms, each end having Divot holes therein there being aligned pivot holes in the ends of said two arms, and a pair of bearing boxes having pivot holes, one can-led by the body proper and one by a bifurcated arm.

5. In scraper apparatus, the combination with a main frame, of spaced apart brackets each bifurcated at its forward end, and each pivotally connected at its rear end to said main frame, a scraper pivotally connected to the bifurcated ends ofsaid brackets, means resiliently connecting each of said brackets to said scraper, and extensible means connecting one bifurcated arm of each bracket to said main frame.

6. In scraper apparatus, the combination with a scraper blade, of a supporting frame, spacedapart supports each pivotally connectedat its rear end to said supporting frame on a transverse axis and each having a forward bifurcated end, mechanism pivotally connecting said scraper blade to both arms of each bifurcated end, and spaced adjusting devices one connected between said supporting frame and one arm of each bifurcated end, and means for controlling said adjusting devices to effect lifting and lowering of said spaced-apart supports and thereby adjust the elevation of said scraper.

7. In scraper apparatus, the combination with a main frame, of an auxiliary frame pivotally connected to the front end of said frame for adjustment relative thereto, a scraper blade, said auxiliary frame including a pair of spaced brackets connected together to move' up and down as a unit, each bracket being bifurcated at its forward end, means pivotally connecting said scraper blade to the front ends of the arms of said bifurcated ends, means resiliently connecting each bracket to said scraper blade, and adjusting means connecting one arm of each bifurcation to said main frame.

8. In scraper apparatus, the combination with a main frame, of an auxiliary frame pivotally connected to the front end of said main frame for adjustment relative thereto, said auxiliary frame including a pair of spaced brackets each bifurcated at one end and pivotally connected to said main frame at its other end, a scraper pivotally connectedto both arms of each bifurcated end, cushioning means between each bracket and said scraper, and adjusting means between the main frame and one arm of each bifurcated end.

9. In scraper apparatus, the combination with a main frame, of an auxiliary frame pivotally connected thereto for adjustment relative thereto, a scraper, said auxiliary frame including a pair of spaced brackets each bifurcated at its forward end and pivotally connected to said scraper, cushioning means between said brackets and said scraper, and adjusting means bebrackets, resilient means between the blade and each bracket rearwardly of its bifurcated ends, and fluid-pressure motors connected between the main frame and one of the arms of each of 5 the bifurcated ends.

RAYMOND W. KEELER.

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