US2242826A - Snowplow - Google Patents

Description

May 20, 1941. R. w. KEELER SNOWPLOW heat 1 Qriginal Filed June 2 Mn A7736 5 z 0 r 2 8 W 7 Sheets-Sheet 2 QAYMOND W. KEELEQ.

Tm .m g 5 m w g M E mm 3 W 1 an PO. 5 wn 1/ an 'Ufl no. no $9 May 20, 1941.

R. W. KEELER May 20, 1941. R. w. KEELER 2,242,825

' SNOWPLOW Original Filed June 23, 1958 '7 Sheets-Sheet s LO (Q ATT'Y RAYMOND W. KEELEQ, v

May 20, 1941.

R. W. KEELER SNOWPLOW Original Filed June 23, 1938 '7 Sheets-Sheet 4 2%, J lO8 VIII.

//VVENT O2,' I QAYMOND W KEELEIZ.

R. W. KEELER May 20, 1941.

SNOWPLOW Original Filed June 25, 1938 '7 Sheets-Sheet 6 any Q wN a 2 a so fA/vf/vrol IZAYMOND W. KEEL-EIZ. BY 04.4. 7/). 77m,

V luB' ATTY May 20, 1941.

R. w. KEELER SNOWPLOW Original Filed June 23, 1958 7 Sheets-Sheet 7 5 M m 151 I 45 fun 45 \so f/vvz/vro/a x40 DAYMOND W. KEELEQ.

BY M m tractor;

Patented May 20, 194

UNITED, STATES PATENT OFFICE sNowrLow 'Raymond W. Keeler, Galion, Ohio, assignor to The Gallon Iron Works 45 Manufacturing Company, a corporation of Ohio Original application June 23, 1938, Serial No.

Divided and this application Febru-' v ary 29, 1940, Serial No. 321,516

'4 Claims. (01. sa -42) This invention relates to a new and improved type of snowplow or similar equipment in which the plow or blade. is positioned in front of a tractor to remove snow or to grade a road.

vide a snowplow attachment to a tractor and means for readily adjusting the position of the snowplow from the operator's position of the tractor. I

A further object of the invention is to provide improved and rugged snowplow supporting and operating means which provide. for very'flexible control of the snowplow while at the same time providing a simple and eflicient 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- of Fig. 1; I

Fig. 3 is a side elevational view of the mechanism of Figs. 1 and 2 shown detached from the Fig. 4 is a plan view of the apparatus of Fig. 3

after the hydraulic control system generallyhas been removed; Fig. 5 is an enlarged detail view of a portion of the supplemental frame comprising the attachment which connects the snowplow 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. '1 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; v

Fig. 8 is a transverse sectional elevational view taken substantially onthe line 84 of Fig. '7. and enlarged looking in the direction of the arrows;

Fig. 9 is a sectional plan view taken on the line 9-9 of. Fig. -8 looking in the direction ofthe arrows; I

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 longitud' alsectional elevational view taken on the line I I-l l of Fig. 10 looking in.

the direction of the arrows;

Fig. 12 is a transverse sectional elevational view taken on the line l2--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 snowplow is .being lowered, Fig. 15 being the condition when the snowplow is being raised, and Fig. 16 being the condition when the hydraulic piston motor has reached one extreme position of expansion; 7

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

Fig. 18 is a side elevational view ofthe mechanism of Fig. 17. v

This application is a division of my co-pending application, Serial No. 215,440, filed June'2 3, 1938, for an improvement in a snowplow.

Referring particularly to Figs. 1 to 5,-inc1usive, of the drawings, it will be seen that my invention comprises a tractor 20 which is essentially a commercial form of tractorhavinga self-contained unitary tractor frame 21 which is formed as a unit with the rear axle housin ear housing and crank case of the tractor motor, which .is'carried under the hood. 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 snowplow or other scraper blade to the tractor 20 so as to operate ahead thereof, 1 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 pivot'al ly 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

7 depending lugs 36 may be integral with the rear 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 adjustment 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.

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 angle members 45 are attached to a transverse angle member 41 between which and'the aforedescribed angle member 44 ispositioned a ends thereof is an angle 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 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 carried by said angle member 56 and the other end of which is carried by the forward extension 68 of the vertical flange of an angle 45 of the mainframe 33. Appropriate removable cotter keys 69 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 the pivot pin 12 which extends between reinforcing ribs 13, 13 rigidly at-- tached to and forming part of the snofiplow 64.

across and between the castings 65, 65 and rigidiy 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 snowplow 64, further resilient connecting means 16, 16 are provided to maintain the slope of the tegral part of the main shank 66 of the casting 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 ofwhich is seen at 68 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 anglemember which is provided at opposite ends with brackets 66, 66. 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-snowplow or scraper blade 64. The auxiliary frame 63 is constructed of a. pair of. similar heavy brackets or castings the structure of which is best seen by reference to Fig. 5

of the drawings. Each of said castings 65 is Extending leading face of the snowplow 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 18 to a bearing box 19 (Fig. 5) formed as an in- 65, and a yoke 86 pivotally attached by a pin 8| to the afore-described ribs 13 of the snowplow 64, which yokes "and 86 are resiliently connected together by a through bolt 82 which extends through each end is provided with a pair of surrounding helical springs. 83 and 84, the latter of which is interposed between the two yokes 11 and'86, and the former of which is interposed between a washer 82' at one endv of the bolt 82 and the yoke .86. It will be evident that the connecting means 16 is designed to maintain the blade85 of the snowplow 64"at a normal predetermined angle but that the snowplow is provided for limited resilient pivotal movement about the axis of the pivot pins 12 both in a clockwise and a counter-clockwise direction with respect to said normal position.

This provides for the absorption of shocks received by the blade 85 in the operation of the snowplow 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 withrespect. to the main frame 38 about the axisof the pivot pins '61,

which is a substantially horizontal *axis, with the consequent raising and lowering of the snowplow 64 or blade 85, I provide at each side of the auxiliary frame 63 a power operated adby a pin 81 toan upright'51 and a spaced vertical plate 88 rigidly attached to the angle member or cross-piece 59, said pin 81 being removably held in place by appropriate cotter keys.

The piston rod 96 of each motor 86 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 95 carried at the lower end of the piston rod 90 to provide a I otally attached by a pin 96 to a bearing box 91 formed integral with the arm II of the casting The out-put of'the pump I04 connected by a pressure conduit III to the control valve IOI. A

return conduit II9 provides a return path from the control valve IOI to the tank 99. Control conduits H9 and I20 extend from the. control valve IOI'to opposite ends of the'cylinders 89 of I the hydraulic piston motors 86-which are con- 65. It will thus be evident that the snowplow 64 is held in any adjusted position by the hydraulic piston motors 86, 86 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 96 are very powerful and constitute 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 snowplow 64. As hereinafter described in full detail,

the motors 86 are locked-in any position of ad-- justment to which they are adjusted thus preventing either expansion or contraction of them under the influence of the snowplow 64 when in I operation.

nected in parallel. Also extending from the output of the pump I0'4 to the tank 99 is a by-pass I conduit I2I controlled by a high pressure relief valve I22.

It maybe stated that the afore-described conduits 9, I are preferably flexible fabricated rubber hoses capable of standing relatively high pressures, which conduits may be readily directed over tortuous paths to reach the hydraulic piston I23 in communication with the conduit I I9 which. is nothing more thana bore in the base I24 pro-.

20 ahead of the cab 26- and is supported upon brackets I00 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. l of the drawings. The operating lever I02 is spring v biased to a normal or neutral position by spring means I03 which are operative to. restore the .control valve IN to its normal or central posi- 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 'I0'I. By reference to Figs. 8 and 9 of the. drawings, it will be seen that the wide gear I06 drives gear I03 keyed to pump shaft I09 through intermediate control gear IIO which is shiftable by a shipper mechanism III along the shaft II2 either into or out of mesh with the wide gear I06. In Figs. 8 and 9 of the drawings, thedriving relation between the gear I06 and the shaft I09 is illustrated. Associated with and operating the shipper I I I is a rock shaft II3 controlled by operating lever I I4 which in turn is controlled by operating rod 5- (Fig.1) within easy reach of the tractor operator. may control the operating rod II6 either to con-. nect'or disconnect the'pump I04 with respect to the tractor motor.

By reference "to Figs. 1, 3 and 13 of the drawings, it will be seen-that a feed conduit I II leads.

It is thus evident that the operator by-pass.

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 I I9, 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 I0 I. 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 one end of which communicates with a chamber viding a return path to the tank 99.

chamber I29 which communicates with the pressure conduit II I. To the. rear of th chamber I29 is a circumferential chamber I 30 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 thebore 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 I351 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 duit I I3 to the tank 99. This is the normal or non-operating position of the control valve IN and provides for no'-loa.d.operation of the pump I04 by virtue of the efore-described low pressure It is to be noted that at the same time the piston rod is locked in its position of ad- Justment by virtue of the fact that the control conduits I I9 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 I 36 and I31.

In Fig. 14. of the drawings, the piston I32 has been moved forwardly from itsnormal position in which position the hydraulic piston motor 86 is expanded by virtue of the fact that pressureconduit I I1 is placed in-communication with control conduit III! by wide groove I36 and control conduit I20 is placed in communication with return conduit II8 by way of ports I35 and bore Fig. 15 illustrates a reverse positioning of the slide valve I32 which is efiective to contract the pistonmotors 66 by virtue of the fact that pressure conduit I I1- isplaced in communication with control conduit I20 by way of wide groove I31 and control conduit I I 9 is in communication with 7 return conduit I I6 by way of ports I35 and bore adjusted. By adjusting the control valve MI by moving the piston I32 to the right, as viewed in Fig. 14., the no-load by-pass for the pump I i will be automatically shut oil? and the piston motors 86 will be expanded. .As illustrated in Fig; 15, when the control valve MI is operated by moving the piston I32 to the left from its normal position, the no-load by-pa ss will again be cut oil and the hydraulic piston motors 86 will be contracted. It is thus manifest that the tractoroperator' need only operate the lever I02 to control the valve IOI to adjust the snowplow 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 connections. v

In Fig. 16 of the drawings the position of the valve MI is the same as illustrated in Fig. 14, but the piston of the illustrated hydraulic piston motor 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 byway of the high pressure bypass I2 I. 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- 86'attempt to move thesnowplow 64 in either directionagainst 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 that the auxiliary frame I40 may simply replace the auxiliary frame 63 with certain modificationsof the snowplow and-hydraulic piston motors,

' as hereinafter described in full detail.

Said auxiliary frame I40 comprises a rear part, I 4| 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 bythe previously described means including the pivot pins 61 similar to the manher in which the castings 6'5 vwere attached thereto as disclosed in detail in Fig. 5 of the drawings and as above described.

Pivotally attached to said rear part I4I of the auxiliary frame I40 is a front part I44, the attachment being eifected'along a central horizontal longitudinal axis by a pivot pin I45 provided with appropriate retaining cotter keys. This pivot pin I45. provides for relative movement of the front and rear parts I44 and I4I about a horizontal longitudinally extending axis which is particularly desirable where the snowplow 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 hori-, zontal, a slight tilting movement about the axis of pin M5 is required to maintain the blade III? of said snowplow I46 in a horizontal position. This will be explained in more complete detail hereinafter.

pivotally supported upon the bearing plate I5I- byfa pivot bolt I5 6 thereby providing pivotal movement'of the semi-circle I53 about the axis of said bolt IN. 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 I56 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 I04 thereby preventing-any damage to the hydraulic control system.

Attention is now directed to Figs. -l'7 and 18 of the drawings wherein there is illustrated a modified form of auxiliary frame I40 which mat 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 with a horizontally disposed transversely aligned journal box I50 which carries a. pivot pin I60 which extends between a pair of ribs I6I on the rear face of the snowplow I46 and provides a pivotal connection between each end of said smicircle I53 and said snowplow I46.

To provide a further and resilient connection between the semi-circle I53 and the snowplow I46 I provide at each end of said semi-circle I53 an upwardly inclined bracket I62 provided with a' through bolt 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 snowplow 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 snowplow I46 about the axis of the two spaced-apart pivot pins I60 as determined by the operating conditions encountered when the snowplow is in actual operation,

As clearly seen by reference to Fig. 1'1 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 snowplow 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 snowplow I46 with respect to the direction of travel of the tractor.

It is manifest that if the frame I40 is adjusted I63 having appropriate when both motors are automatically stopped by the resistance offered by the road surface to fur-- the pivot pin I45 with the motors 86 expanded to on the pivots 61 to move the snowplow I46 from different lengths accordingly. After such adjustments have been effected, the snowplow 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 I previously described, in that said yokes 93' are 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 I of the frame I40. is free to pivot about the longitudinallytransverse 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 will be in a relatively low position and the other end in a relatively high position. Now upon reversing the" motors 86 to lower the snowplow 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 edgeof the cutting blade I41 to move to a horizontal plane. allel' 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 built up from relatively heavy blocks I10 to which are bolted a pair of side plates I II. The side plates I1I of the yokes 93' are pivotally attached by pivot pins I12 to bearing boxes I13 carried upon outward extensions of the afore-described angle members I50. It is thus manifest that the hydraulic piston motors 86 may be operated in the manner previously described in connection with Figs. 1 to 1'? of the drawings, to adjust the auxiliary frame I40 about the axis of the pins 61 and thereby adjust the snowplow 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 snowplow ahead of it, all from a single station.

It is preferred to positively hold the snowplow down to its work with the valve mechanism in the position shown in Fig. 13, but if at anytime the snowplow can not cut a path for itself, such as when obstructed by or riding up on solid ice, the valve mechanism may be moved to the position shown in Fig. 15 to eifect lifting of the framework supporting the snowplow and after such ofbstructio'n has been passed the valve mechanism may be moved to the positions shown in Figs. 14 and 16 and finally restored to the position shown in Fig. 3. Adjustment of the snowplow upwardly and downwardly is very easily and readily effected by the operator simply by controlling the lever I02 in response to which very powerful poweroperating hydraulic control mechanism comes into play to adjust the snowplow or grader tool and to hold it resiliently in any position of adjustment.

' Figs. 17 and 18 of the drawings, it is further The motors, 85 being connected in parpossible to adjust the angle of attack of the snowplow 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.snowplow orgrader 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. 1'7 and 18 that the reciprocable hydraulic motors 86, 86 are arranged in parallelism at the 18 andsuch nuts may be locked in adjusted positions. v

The springs 92 and 94 above and below the blocks I10 are preferably stiff and heavy so as to be sufficiently 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 cylinder 06, 86. Consequent1y,the nuts at the extreme lower ends of the piston rod extensions are not tightened sufliciently to place any initial tension in the springs 92 and94, these nuts serving merely to hold the springs in place against the blocks I10. However, downward pressure on the scraper blade I41 is yieldingly exerted through the springs 92 and lifting of the snowplow 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 movemerits 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 I41 strikes an obstruction the tilting of the snowplow I46 on-the axis I60 will be yieldingly resisted by thesprings I68 and the recoil will be absorbed by the springs I61. Due to the presence of the stirrups I65 pivoted at their forward ends to the back side of the snowplow and the co-relation between the cross-pieces of these stirrups nd the springs I61, 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 snowplow, Initially the nuts I64 merely hold the springs I61 and I68 in place against their end abutments.- i

Obviously those skilled the art may make variouschanges 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.

Having thus described and shown an embodi-. ment of my invention, what I desire to secure by on a horizontal transverse axis, said auxiliary frame comprising two sections pivoted together on a longitudinal axis, a scraper, mechanism mounting said scraper on the forward section of said auxiliary frame'for adjustment relative thereto on an upright axis, spaced-apart fluid-pressure motors connected between said main frame and the forward section of the auxiliaryframe at transversely spaced-apart points, and a fluidpressure control system for operation of said motors in parallel to effect transverse tilting of the forward section of the auxiliary frame on said longitudinal axis when the scraper occupies a position extending diagonally of the line of draft of the machine and said auxiliary frame is moved downwardly to cause the entire length of the lower edge of the scraper to engage the ground, the construction and arrangement being such that after the lower edge of the scraper has been thus adjusted the motors may be operated equally to adjust the elevation of the scraper equally relatively to the road surface.

2. In scraper apparatus, the combination with a main frame, of a supplemental frame pivoted thereto on a transverse horizontal axis, a tertiary frame pivoted to said supplemental frame on a longitudinal axis, a moldboard pivotally mounted on said tertiary frame for adjustment relative thereto on an upright axis, means for holding said moldboard in adjusted angular relation to the path of travel of the scraper apparatus, spaced-apart fluid pressure motors between said main frame and said tertiary frame, and a fluid pressure system for operating said motors in parallel to push down on the tertiary frame to bring the lower cutting edge of the ,moldboard into contact with the ground surface, said fluid pressure system including equalizing means to allow the stopping of one fluid-pressure motor while the other continues to act to cause said tertiary-frame to tilt on said longitudinal axis until the lower cutting edge of the moldboard contacts with the ground surface throughout its entire length.

tiary frame on an upright axis, means for hold-,

ing the moldboard in adjusted position relative to said tertiary frame with the moldboard inclined relative to the path of travel of said scraper apparatus, spaced-apart fluid pressure motors connected to said tertiary frame, and a fluid pressure control system connecting said fluid pressure motors in parallel for double action in either positively lifting or positively lowering said tertiary frame, said fluid-pressure control system comprising automatic by-pass to permit expansion of said motorsto unequal lengths to 'effect leveling of the lower cutting edge of the moldboard by automatic tilting of the tertiary frame on said longitudinal axis in response to one end of the moldboard contacting with the ground and the expansion of the motor on that side of the machine remote from the ground contacting end of the moldboard.

4. In scraper apparatus, the combination with a a main frame, of an elongated scraper, mechanism flexibly connecting said scraper to said frame for adjustment in elevation and in angular relation to the path of travel of the scraper apparatus, spaced-apart fluid pressure motors connected to said mechanism for effecting adjustment in elevation of said scraper including pushing down of the lower edge of the scraper against the ground surface, said mechanism being so constructed and arranged that when said scraper is thus pushed said motors in parallel but enabling said motors down it will be automatically moved to such pcsito be expanded to different, lengths to secure the tion that its lower edge contacts with the ground aforesaid contact of the lower edge of the scraper surface substantially throughout its length while with the ground surface throughout its length 4 the scraper is in the aforesaid angular position, 5 while in inclined position.

and a fluid pressure control system for operating RAYMOND W. KEEIER.

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