US3337974A

US3337974A - Bulldozer

Info

Publication number: US3337974A
Application number: US418791A
Authority: US
Inventors: George A Fisher
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1964-12-16
Filing date: 1964-12-16
Publication date: 1967-08-29
Anticipated expiration: 1984-08-29

Description

ug- 29, 1967 G. A. FISHER 3,337,974

BULLDOZER Filed Dec. l6, 1964 3 Sheets-Sheet l IN VEN TOR.

G. A. FISHER Aug. 29, 1967 BULLDOZER 5 Sheets-Shet 3 Filed Dec. 16, 1964 INVENTOR. Geo/ye fl; @1 61 BY A'TTORNEV 3,337,974 Patented Aug. 29, 1967 3,337,974 BULLDOZER George A. Fisher, Mentor on the Lake, Ohio, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Dec. 16, 1964, Ser. No. 418,791 3 Claims. (Cl. 37-144) ABSTRACT OF THE DISCLOSURE A bulldozer linkage assembly of the parallelogram type which is operative through fluid pressure poweroperated cylinders to angle the blade about a longitudinal axis of the vehicle, to pitch the blade about a transverse axis, and to raise the blade.

This invention relates generally to bulldozers and more particularly to a quadrangular or parallelogram linkage which operatively connects the blade element with the vehicle. a

It is not new to utilize a parallelogram type linkage for purposes of supporting a dozer blade, and one example of this type of arrangement can be seen in United States Patent No. 2,974,430, filed Apr. 8, 1957, in the name of Ralph I. Bernotas and assigned to the assignee of this invention. More specifically, the linkage shown in the aforementioned patent comprises a pair of support arms located in substantially parallel planes which are connected at spaced points to the vehicle and the dozer blade. An hydraulically actuated double-acting jack is mounted on the vehicle and connects with the blade for positioning the latter between a dozing and carry position.

One advantage of this type of linkage is that it permits the dozer blade to be raised to a carry position while maintaining'the blade in a vertical plane so that during a material stockpiling operation the material is more efl'lciently piled toward the top of the heap. In other work, such as in heavy pioneering work, the dozer blade can be raised to provide its full surface for striking trees and other objects which are to be removed at points above the ground so that increased leverage is applied during the operation.

The linkage as shown in the above-mentioned patent is capable of positioning the blade as aforedescribed; however, where it is desired to pitch or angle the blade, for example for a ditching or crowning operation, such positioning cannot be realized without substituting links of different lengths or "as in the'case of the above linkage, without requiring manual adjustment of screw means provided for the angling position. As should be apparent in any earth-moving operation, it is important to have the blade adjustable quickly so that the machine can be efiiciently utilized.

Another disadvantage of the typical parallelogram linkage utilized for supporting dozer blades is that the linka'ge tends to sufier from inherent instability whenever the blade is angled for ditching or crowning work.

Accordingly, one object of the present invention is to provide a bulldozer linkage assembly of the parallelogram type which is operative through fluid pressure poweroperated cylinders to angle the blade about a longitudinal axis of the vehicle, to pitch the blade about a transverse axis, and to raise the blade; all the operations being accomplished without requiring the vehicle operator to leave the vehicle.

Another object of the present invention is to provide a parallelogram type linkage for a bulldozer assembly that is stable during all normal work operations for a dozer.

The above objects and others are accomplished with a dozer assembly mounted on the front of a tractor type vehicle and comprising a pair of transversely spaced push arms pivotally connected at one end thereof to the vehicle for movement about a first transverse pivot axis. A dozer blade is mounted to the other ends of the push arms for pivotal movement about a second transverse axis and a fluid operated double-acting jack extends between each of the push arms and the vehicle for raising and lowering the blade between carry and dozing positions. A strut member is provided in a plane substantially parallel to that of the push arms and extends between the dozer blade and the vehicle. In the preferred form, the strut member takes the form of a double-acting jack which serves to pitch the dozer blade fore and aft about its pivotal connectionwith its push arms. All pivotal connections between 'the linkage of 'the vehicle and the dozer blade are universal connections thereby permitting the blade to be angled about the longitudinal axis of the vehicle whenever one of the push arm jacks is extended and the other is contracted.

A more complete understanding of the invention can be derived from the following detailed description when taken in conjunction with the drawings in which:

FIGURE 1 is an elevational view showing a rubbertired tractor equipped with a bulldozer linkage assembly made in accordance with this invention;

FIGURE 2 is a view taken on line 2-2 of FIG- URE 1;

FIGURE 3 is a front elevational view of the vehicle of FIGURE 1 and illustrates two of the positions of the blade, and

FIGURE 4 is an enlarged view of the bulldozer linkage assembly and illustrates the various positions of the dozer blade.

Referring now to the drawings and more specifically to FIGURES 1, 2 and 3 thereof, a rubber-tired tractor or vehicle is shown comprising a body 10 having an operators station 12 provided thereon. The forward portion of the body supports a dozer assembly 14 made in accordance with the invention, which as seen in FIG- URES 2 and 3 comprises a pair of push arms 16 and 18 located inboard of the front wheels and mounted at their respective inner ends by transversely aligned universal connections 20 and 22. The push arm 16 includes an elongated rod portion 24 that is connected to a C- .shaped frame 26 that extends forwardly and pivotally supports one end of a dozer blade 28 through pivotal connections 30 and 32. The push arm 18 is identical in construction to the push arm 16 and therefore also comprises a rod portion 34 fixed to a C-frame 36 which, in this case, supports the other end of the dozer blade through pivotal connections 38 and 40. As should be apparent, the pivotal connections between the C-frames and the dozer blade are axially aligned and therefore located on a common transverse axis about which the dozer blade may be pitched forwardly-and rearwardly in a manner to be described.

A pair of double-acting hydraulic jacks 42 and 44 are also provided between the dozer blade and the vehicle with the cylinder ends of the respective iacks being connected by ball and socket connections 46 and 48 to the C-frames 16 and 18. The rod ends of the respective jacks are also connected by ball and socket connections 50 and 52 to the vehicle at points located vertically above the universal connections between the push arms and the vehicle. In addition, a double-acting hydraulic tilt jack 54 is located in a plane parallel to the planes of the push arms and also extends between the vehicle and the dozer blade. In this connection, it can be seen in FIGURE 1 that the tilt jack 54 is connected by a ball and socket connection 56 to the vehicle at a point lying on a transverse horizontal axis that passes through the centers of the universal connections 50 and 52. A similar ball and socket connection 58 joins the forward end of the jack 54 with the upper portion of the blade 28 midway between the ends thereof. Thus, as evidenced from the drawings, the above-described arrangement of push arms, tilt and lift jacks provides a parallelogram type linkage which permits the dozer blade to be raised from a fully lowered to a fully raised position while maintaining substantially the same position with respect to the ground and the vehicle as seen in FIGURE 4.

As aforementioned, all of the hydraulic jacks incorporated with this invention are of the double-acting type comprising the usual piston and cylinder construction which permits them to be extended and contracted under power by pressuring one end of the cylinder while venting the other.

In addition, it will be noted that the jacks form part of a hydraulic circuit that includes the usual pump, reservoir, and fluid directional control valve; the latter being located at the drivers station and designated by the numeral 60. This circuit and the various interconnections therein are of conventional design and well known to those skilled in the art.

It will be noted that by universally connecting the jacks 42, 44 and 54 between the vehicle and the dozer blade and similarly providing connections of this sort between the push arms and the vehicle, the dozer blade 28 may be moved to various positions and still maintain the stability required for various operations. For example, by concurrent contraction of the lift jacks 42 and 44, the dozer blade 28 can be moved from the position shown by phantom lines in FIGURE 4 and indicated by the letter A to an intermediate or full line position B and to a raised position C. In order to angle the blade about a longitudinal axis of the vehicle so that the blade moves counterclockwise to assume the position indicated by the phantom lines in FIGURE 3, the lift jack 42 is extended while jack 44 is contracted. To angle the blade in the opposite direction, the lift jack 42 is contracted and the lift jack 44 extended. For purposes of pitching the blade forward or aft about the tranverse axis passing through the pivotal connections 30, 32, 38 and 40, the double-acting tilt jack 54 can be selectively extended or contracted.

From the above description, it should be apparent that this parallelogram linkage provides a variety of positions of the dozer blade for accomplishing all operations required of a bulldozer. The linkage is of compact design with the main elements thereof located in positions which effectively transmit forces directly to the frame during the normal dozing operation. Moreover, it will be noted that by locating the lift jacks diagonally between the lower end of the dozer blade and the vehicle, a rigid support is provided which prevents the blade from being pulled down into the material being dug which is a common difficulty experienced with blades during dozing operations.

Various changes and modifications can be made in this construction without departing from the spirit of the invention. Such changes and modifications are contemplated by the inventor and he does not wish to be limited except by the scope of the appended claims.

What is claimed is:

1. In combination with a vehicle having front and rear axles, ground-engaging wheels supported on opposite ends of the respective axles, a dozer assembly mounted to the front end of said vehicle, said dozer assembly comprising a pair of transversely spaced push arms pivotally connected at one end thereof to said vehicle for movement about a first transverse pivot axis, each of said push arms being located adjacent to and inboard of the front wheels, at dozer blade mounted to the other end of said push arms for pivotal movement about a second transverse axis, a first double-acting jack extending between each of said push arms and said vehicle for raising and lowering said push arms between carry and dozing positions, means pivotally connecting one end of said jack to said push arm at a point on said second transverse axis, means pivotally connecting the other end of said jack to said vehicle at a point vertically spaced from said first transverse axis, a second double-acting.

jack for tilting said blade about said second transverse axis and lying in a plane substantially parallel to a plane passing through the push arms, means pivotally connecting one end of said second jack to an upper portion of said dozer blade at a point vertically spaced from the second transverse axis, and means pivotally connecting the other end of said second jack to the vehicle at a point located substantially midway between the points of connections between the first jacks and the vehicle.

2. In combination with a vehicle, a dozer assembly mounted to said vehicle, said dozer assembly comprising a pair of transversely spaced push arms universally pivotally connected at one end thereof to opposite sides of said vehicle at points that define a first transverseaxis, a dozer blade mounted to the other end of said push arms for pivotal movement about a second transverse axis, a pair of double-acting jacks extending between said push arms and said vehicle, means universally pivotally connecting one end of each of said jacks to said push arm at a point located on said second transverse axis, means universally pivotally connecting the other end of each of said jacks to said vehicle at a point vertically spaced from said first transverse axis, a strut member, means universally pivotally connecting one end of said strut member to an upper portion of said dozer blade at a point vertically spaced from the second transverse axis, means universally pivotally connecting the other end of said strut member to the vehicle at a point axially aligned with and substantially midway between the points of connections of the jacks and the vehicle, and said dozer blade adapted to be raised from a dozing position about said first transverse axis when said pair of jacks are concurrently contracted, and said dozer blade adapted to be angled about an axis extending longitudinally of the vehicle when one of said pair of jacks is expanded.

3. In combination with a vehicle having front and rear axles, ground-engaging wheels supported on opposite ends of the respective axles, a dozer assembly mounted to the front end of said vehicle, said dozer assembly comprising a pair of transversely spaced push arms universally pivotally connected at one end thereof to opposite sides of said vehicle at points lying in a first transverse pivot axis, each of said push arms being located ad- 'jacent to and inboard of the front wheels, a dozer blade mounted to the other end of said push arms for pivotal movement about a second transverse axis, a pair of double-acting jacks extending between said push arms and said vehicle, means universally pivotally connecting one end of each of said jacks to the associated push arm at a point located on said second transverse axis, means universally pivotally connecting the other end of each of said jacks to said vehicle at a point vertically spaced from said first transverse axis, a strut member, means universally pivotally connecting one end of said strut member to an upper portion of said dozer blade at a point vertically spaced from the second transverse axis, means universally pivotally connecting the other end of said strut member to the vehicle at a point axially aligned with and substantially midway between the points of connections of the jacks and the vehicle respectively, said dozer blade adapted to be raised from a dozing position about said first transverse axis when said pair of jacks are concurrently contracted, and adapted to be angled about an axis extending longitudinally of the vehicle when one of said pair of jacks is expanded and the other is contracted.

References Cited UNITED STATES PATENTS FOREIGN PATENTS 6/ 1961 Australia.

ABRAHAM G. STONE, Primary Examiner.

R. L. HOLLISTER, Assistant Examiner.

Claims

1. IN COMBINATION WITH A VEHICHLE HAVING FRONT AND REAR AXLES, GROUND-ENGAGING WHEELS SUPPORTED ON OPPOSITE ENDS OF THE RESPECTIVE AXLES, A DOZER ASSEMBLY MOUNTED TO THE FRONT END OF SAID VEHICLE, SAID DOZER ASSEMBLY COMPRISING A PAIR OF TRANSVERSELY SPACED PUSH ARMS PIVOTALLY CONNECTED AT ONE END THEREOF TO SAID VEHICLE FOR MOVEMENT ABUT A FIRST TRANSVERSE PIVOT AXIS, EACH OF SAID PUSH ARMS BEING LOCATED ADJACENT TO AND INBOARD OF THE FRONT WHEELS, A DOZER BLADE MOUNTED TO THE OTHER END OF SAID PUSH ARMS ARMS FOR PIVOTAL MOVEMET ABOUT A SECOND TRANSVERSE AXIS, A FIRST DOUBLE-ACTING JACK EXTENDING BETWEEN EACH OF SAID PUSH ARMS AND SAID VEHICLE FOR RAISING SAND LOWERING SAID PUSH ARMS BETWEEN CARRY AND DOZING POSITIONS, MEANS PIVOTALLY CONNECTING ONE END OF SAID JACK TO SAID PUSH ARM AT A POINT ON SAID SECOND TRANSVERSE AXIS, MEANS PIVOTALLY CONNECTING THE OTHER END OF SAID JACK TO SAID VEHICLE AT A POINT VERTICALLY SPACED FROM SAID FIRST TRANSVERSE AXIS, A SECOND DOUBLE-ACTING JACK FOR TILTING SAID BLADE ABOUT SAID SECOND TRANSVERSE AXIS AND LYING IN A PLANE SUBSTANTIALLY PARALLEL TO A PLANE PASSING THROUGH THE PUSH ARMS, MEANS PIVOTALLY CONNECTING ONE END OF SAID SECOND JACK TO AN UPPER PORTION OF SDAID DOZER BLADE AT A POINT VERTICALLY SPACED FROM THE SECOND TRANSVERSE AXIS, AND MEANS PIVOTALLY CONNECTING THE OTHER END OF SAID SECOND JACK TO THE VEHICLE AT A POINT LOCATED SUBSTANTIALLY MIDWAY BETWEEN THE POINTS OF CONNECTIONS BETWEEN THE FIRST JACKS AND THE VEHICLE.