UTILITY LOADER WITH HIGH LIFT LOADER ARMS AND UNIFYING HAND GRIP FOR DUAL TRACTION CONTROL LEVERS

Abstract

A compact utility loader is operated by a standing operator at the rear of a frame. A loader arm assembly comprises a scissors linkage on either side of the frame nesting around the prime mover. Each scissors linkage has an upper loader arm that is pivoted at its rear end to rears ends of a pair of lower loader arms such that the pivot connections to the upper loader arm move upwardly and forwardly relative to the frame during elevation of the loader arm assembly to provide a high lift capability. The frame is self-propelled by a differential drive and steering system that is operated by dual levers. A hand grip extends between and unifies the operation of the levers to permit the operator to more easily move the levers in the ways that are needed to provide either straight motion of the frame or turns of the frame.

Claims

1. A compact utility loader, which comprises: (a) a frame carrying a prime mover; (b) ground engaging members carried by the frame with at least one ground engaging member on each side of the frame being powered to self-propel the frame; (c) a control console at a rear end of the frame carrying controls that are manipulated to operate the loader; (d) a loader arm assembly having a pair of linkages on opposite sides of the frame, wherein each linkage comprises: (i) a loader arm having a front end and a rear end; and (ii) first and second connecting arms, wherein each connecting arm has a front end and a rear end, wherein the front ends of the connecting arms are pivotally connected to a front support assembly that is fixed to a front portion of the frame, and wherein the rear ends of the connecting arms are pivotally connected to the rear end of the loader arm with the rear end of the loader arm being free to move upwardly and forwardly relative to the frame as the loader arm assembly is elevated between a lowermost, fully retracted position thereof and an uppermost, fully extended position; and (e) an outdoor work operation tool or implement pivotally carried on the front ends of the loader arms.

2. The loader of claim 1, wherein the front support assembly comprises laterally spaced support beams, wherein each support beam extends vertically upwardly relative to the frame and includes a U-shaped cross-section having an open side that faces rearwardly, and wherein the front ends of the connecting arms of each linkage extend into and are pivotally journalled within the U-shaped cross-section of a different one of the support beams to pivotally couple the loader arm assembly to the frame.

3. The loader of claim 2, wherein the support beams have interior side walls that are further joined together by at least a partial front wall extending laterally between and joining the support beams.

4. The loader of claim 2, wherein the connecting arms of each linkage comprise cast arms.

5. The loader of claim 2, further including a cross member that extends laterally between and joins top ones of the connecting arms to each other.

6. The loader of claim 2, wherein the support beams have exterior side walls that mount an outwardly extending pivot pin that is located outside of the U-shaped cross-sections of the side walls, the pivot pin pivotally mounting one end of an actuator that is part of each linkage with the actuator extending rearwardly from the pivot pin to an opposite end that is pivotally journalled on the loader arm ahead of the pivots that journal the connecting arms to the loader arm.

7. The loader of claim 6, wherein the pivot pins are located within substantially enclosed pockets extending laterally from the exterior side walls of the support beams with the pockets being open at a rear side thereof.

8. The loader of claim 6, wherein the actuators extend substantially straight rearwardly as the actuators extend between the support beams of the front support assembly and the loader arms of the linkages, and wherein bottom ones of the connecting arms of the linkages have portions that curve inwardly to avoid hitting or interfering with the actuators.

9. The loader of claim 1, further including a rear foot platform carried on the rear end of the frame for permitting the controls to be accessible from behind by an operator who stands on the rear foot platform.

10. The loader of claim 1, wherein the connecting arms are configured to move the work operation tool or implement in a substantially vertical lift path as the loader arm assembly is elevated between the lowermost, fully retracted position thereof and the uppermost, fully extended position thereof.

11. A compact utility loader, which comprises: (a) a frame carrying a prime mover; (b) ground engaging members carried by the frame with at least one ground engaging member on each side of the frame being powered to self-propel the frame; (c) a control console at a rear end of the frame carrying controls that are manipulated to operate the loader; (d) a loader arm assembly, which comprises: (i) a pair of loader arms that are laterally spaced from one another with the loader arms comprising a left loader arm on a left side of the frame and a right loader arm on a right side of the frame; (ii) a pair of first connecting arms that are laterally spaced from one another with the first connecting arms comprising a left first connecting arm on a left side of the frame and a right first connecting arm on a right side of the frame; (iii) a pair of second connecting arms that are laterally spaced from one another with the second connecting arms comprising a left second connecting arm on a left side of the frame and a right second connecting arm on a right side of the frame; and (iv) wherein the first and second connecting arms pivot relative to the frame about first and second laterally extending, horizontal pivot axes that are fixed relative to the frame and about third and fourth laterally extending, horizontal pivot axes that are fixed relative to the loader arms but are movable relative to the frame such that rear ends of the loader arms are free to move relative to the frame as the loader arm assembly is elevated between a lowermost, fully retracted position thereof and an uppermost, fully extended position; and (v) wherein the first and second pivot axes are forward of the third and fourth pivot axes in the lowermost position of the loader arm assembly, as the loader arm assembly is elevated between the lowermost and uppermost positions thereof, and in the uppermost position of the loader arm assembly; and (e) an outdoor work operation tool or implement pivotally carried on front ends of the loader arms.

12. The loader of claim 11, further including: (i) a pair of actuators that are laterally spaced from one another with the actuators comprising a left actuator on a left side of the frame and a right actuator on a right side of the frame; and (ii) wherein the actuators pivot relative to the frame about a fifth laterally extending, horizontal pivot axis that is fixed relative to the frame and about a sixth laterally extending, horizontal pivot axis that is movable relative to the frame, and wherein the first, second and fifth pivot axes are forward of the third, fourth and sixth pivot axes in the lowermost position of the loader arm assembly, as the loader arm assembly is elevated between the lowermost and uppermost positions thereof, and in the uppermost position of the loader arm assembly.

13. The loader of claim 12, further including: (i) a pair of support members that are fixed to a front portion of the frame, wherein the support members are laterally spaced from one another with the support members comprising a left support member on a left side of the frame and a right support member on a right side of the frame; (ii) wherein the left first connecting arm has a left first connecting arm pivot connection to the left support member, the left second connecting arm has a left second connecting arm pivot connection to the left support member, and the left actuator has a left actuator pivot connection to the left support member; (iii) wherein the right first connecting arm has a right first connecting arm pivot connection to the right support member, the right second connecting arm has a right second connecting arm pivot connection to the right support member, and the right actuator has a right actuator pivot connection to the right support member; and (iv) wherein the first connecting arm pivot connections are aligned with one another to form a first pair of pivot connections that define the first pivot axis, the second connecting arm pivot connections are aligned with one another to form a second pair of pivot connections that define the second pivot axis, and the actuator pivot connections are aligned with one another to form a third pair of pivot connections that define the fifth pivot axis.

14. The loader of claim 13, wherein the support members are further connected to each other by at least one cross member.

15. The loader of claim 13, wherein each support member comprises a pair of laterally spaced side walls that define a cavity therebetween with the side walls further being connected to each other by a cross member, and wherein two pairs of the three pairs of pivot connections are located within the cavities of the support members.

16. The loader of claim 15, wherein the two pairs of pivot connections that are located within the cavities of the support members comprise the first and second pairs.

17. The loader of claim 15, wherein each support member includes a pocket that is exterior to the cavity formed within the support member, and wherein the third pair of the three pairs of pivot connections is located within the pockets of the support members.

18. The loader of claim 15, wherein the support members are further connected to each other by at least one cross member.

19. The loader of claim 11, further including a rear foot platform carried on the rear end of the frame for permitting the controls to be accessible from behind by an operator who stands on the rear foot platform.

20. A compact utility loader, which comprises: (a) a frame carrying a prime mover; (b) ground engaging members carried by the frame with at least one ground engaging member on each side of the frame being powered to self-propel the frame; (c) a control console at a rear end of the frame carrying controls that are manipulated to operate the loader; (d) a loader arm assembly having a pair of linkages on opposite sides of the frame, wherein each linkage comprises: (i) a loader arm having a front end and a rear end; and (ii) first and second connecting arms, wherein each connecting arm has a front end and a rear end, wherein the front ends of the connecting arms are pivotally connected to a front support assembly that is fixed to a front portion of the frame, and wherein the rear ends of the connecting arms are pivotally connected to the rear end of the loader arm with the rear end of the loader arm being free to move upwardly and forwardly relative to the frame as the loader arm assembly is elevated between a lowermost, fully retracted position thereof and an uppermost, fully extended position; (e) wherein the first connecting arms on the opposite sides of the frame comprise a first pair of connecting arms and the second connecting arms on the opposite sides of the frame comprise a second pair of connecting arms, and wherein the connecting arms in the first pair of the connecting arms are fixedly connected to each other by a laterally extending cross member; and (f) an outdoor work operation tool or implement pivotally carried on the front ends of the loader arms.

21. The loader of claim 20, wherein the front support assembly comprises a pair of support beams on opposite sides of the frame, the support beams being fixedly connected to each other by at least one cross member.

22. The loader of claim 20, wherein the cross member in the first pair of the connecting arms is located forwardly of the prime mover.

23. The loader of claim 20, wherein the cross member is located on the front ends of the connecting arms in the first pair of connecting arms.

24. The loader of claim 23, wherein the cross member is located substantially immediately behind where the front ends of the connecting arms in the first pair of connecting arms pivotally connect to the front support assembly.

25. The loader of claim 23, wherein the connecting arms in the first pair of connecting arms pivotally connect to the front support assembly at a vertical location that is higher than a vertical location where the connecting arms in the second pair of connecting arms pivotally connect to the front support assembly.

26. The loader of claim 25, wherein the connecting arms in the first pair of connecting arms pivotally connect to the front support assembly at a fore-and-aft location that is rearward of a fore-and-aft location where the connecting arms in the second pair of connecting arms pivotally connect to the front support assembly.

27. The loader of claim 23, wherein the front support assembly comprises a pair of support beams on opposite sides of the frame, the support beams being connected to each other by at least one cross member.

28. The loader of claim 23, wherein the loader arms are connected to one another by a laterally extending cross member that is fixed to the loader arms, wherein the cross member on the loader arms is located proximate to a front portion of the front support assembly when the loader arm assembly is disposed in the lowermost, fully retracted position thereof.

29. The loader of claim 28, wherein the cross member on the loader arms is disposed forward of and below the cross member on the first pair of connecting arms when the loader arm assembly is disposed in the lowermost, fully retracted position thereof.

30. The loader of claim 20, further including a rear foot platform carried on the rear end of the frame for permitting the controls to be accessible from behind by an operator who stands on the rear foot platform.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] This invention will be described more specifically in the following Detailed Description, when taken in conjunction with the following drawings, in which like reference numerals refer to like elements throughout.

[0011] FIG. 1 is a perspective view of a compact utility loader according to this invention;

[0012] FIG. 2 is a side elevational view of the loader of FIG. 1, particularly illustrating the high lift loader arms in their lowermost, fully retracted position;

[0013] FIG. 3 is a side elevational view similar to FIG. 2, particularly illustrating the high lift loader arms in their uppermost, fully extended position;

[0014] FIG. 4 is an exploded perspective view of various portions of the high lift loader arm assembly of the loader of FIG. 1;

[0015] FIG. 5 is a bottom plan view of the portions of the high lift loader arm assembly shown in FIG. 4, particularly illustrating the loader arm assembly portions in an assembled condition with one mounting plate thereof having been removed for the purpose of clarity;

[0016] FIG. 6 is a perspective view of the traction control levers and the unifying hand grip portion of the loader of FIG. 1, particularly illustrating the unifying hand grip in an assembled condition atop the traction control levers;

[0017] FIG. 7 is a perspective view similar to FIG. 6, but showing the hand grip in an exploded and disassembled form relative to the traction control levers;

[0018] FIG. 8 is a side elevation view of one of the halves of the hand grip in engagement with the spherical balls or knobs of the traction control levers, particularly illustrating the slots on either side of the hand grip which receive the knobs of the traction control levers;

[0019] FIG. 9 is a perspective view of what is shown in FIG. 8;

[0020] FIG. 10 is a cross-sectional side elevation view of the slot configuration in the hand grip as it is received on the knob of one of the traction control levers;

[0021] FIG. 11 is a bottom plan view of the hand grip showing the asymmetric shape of the laterally extending slots therein;

[0022] FIG. 12 is a perspective view of the hand grip being used to execute a spin or zero radius turn to the left with one half of the hand grip having been removed for the sake of clarity; and

[0023] FIG. 13 is a top plan view of the hand grip as depicted in FIG. 12.

DETAILED DESCRIPTION

[0024] Referring first to FIGS. 1 and 2, one embodiment of a compact utility loader according to this invention is illustrated generally as 2. Loader 2 comprises a small chassis or frame 4 that mounts a pair of driven, ground engaging endless tracks 6 on opposite sides thereof. Tracks 6 may be replaced by pairs of driven ground engaging wheels on opposite sides of frame 4 if so desired.

[0025] Whether the ground engaging traction members of loader 2 are endless tracks or wheels, they are powered by a prime mover 8, such as but not limited to an internal combustion gasoline or diesel engine, which is carried on frame 4. Prime mover 8 is located substantially over a central portion of frame 4 immediately ahead of an operator's control console 10 located at the rear of frame 4. Control console 10 is directly in front of a foot platform 12 that allows the operator to ride on loader 2 in a standing position at the rear of loader 2. Alternatively, the foot platform 12 may be deleted from loader 2 if so desired in which case the operator would walk on the ground behind loader 2 rather than riding on loader 2. In this alternative walk behind configuration control console 10 would be located at a convenient height relative to the ground to allow the controls to be easily reached by an operator who walks on the ground behind loader 2 rather than riding on an elevated foot platform. Loaders 2 of the general type shown herein are manufactured and sold by The Toro Company, in both wheeled and tracked versions as well as ride on and walk behind versions, under the Dingo brand name.

[0026] Loader 2 has a loader arm assembly 14 that in a lowermost, fully retracted position nests around prime mover 8 as shown in FIG. 2. A tool or implement for performing some type of outdoor maintenance or work operation is carried on the front end of loader 2 arm assembly in advance of frame 4 of loader 2. In the embodiment of loader 2 shown herein, the implement comprises a pivotal dump bucket 16 for scooping up dirt, mulch or other materials and for then subsequently dumping the materials at another location, such as into a dump truck. Many other outdoor maintenance or work implements, such as trenchers, augers, chippers, fork lifts, etc., could be interchangeably used on the front end of loader arm assembly 14 in place of dump bucket 16.

[0027] An aspect of this invention is the use of a high lift loader arm assembly that accommodates the small form of loader 2. Referring now to FIG. 3, loader arm assembly 14 comprises a pair of scissor shaped loader arm linkages 18 positioned on opposite sides of loader frame 4 directly outboard of prime mover 8. Linkages 18 are identical to one another so a description of one linkage 18 will suffice to describe the other. FIG. 3 illustrates linkage 18 in the uppermost, fully extended, high lift position of loader arm assembly 14. In this position, dump bucket 16 has been elevated a considerable distance above the ground.

[0028] As shown in FIG. 3, each linkage 18 comprises an upper loader arm 20 and two lower loader arms 22, 24 that are pivotally connected by pivots 26, 28 to the rear portion of upper loader arm 20. A hydraulic cylinder 30 has its piston rod 32 pivotally connected to upper loader arm 20 somewhat forwardly of pivots 26, 28 for lower loader arms 22, 24. Hydraulic cylinder 30 is the actuator that lifts and lowers loader arm assembly 14 between its FIG. 2 and FIG. 3 positions and any desired position in between. Other actuators, such as electrical actuators, could be used in placed of hydraulic cylinders 30 used in linkages 18.

[0029] Pivots 26, 28 in each linkage 18 are not attached to loader frame 4, but only serve to pivotally connect the two lower loader arms 22, 24 to upper loader arm 20. This permits the rear end of linkage 18 to elevate and move forwardly as loader arm assembly 14 is elevated by hydraulic cylinder 30. Compare FIG. 2 to FIG. 3. In FIG. 2, loader arm pivots 26, 28 are low and rearwardly located relative to loader frame 4. In the high lift position of FIG. 3, loader arm pivots 26, 28 have significantly risen and moved somewhat more forwardly than the position they occupied in FIG. 2. It is this ability of linkages 18 to elevate and move forwardly as upper loader arm 20 scissors away from lower loader arms 22, 24 that provides the high lift function.

[0030] Loader arm assembly 14 of this invention has sufficient strength to provide high lift even when elevating a fully loaded dump bucket to significantly higher distances above the ground than is typical for a normal loader arm assembly. Referring now to FIG. 4, loader arm assembly 14 includes a squat, robust support assembly 33 that is fixed to loader frame 4 generally at the front of frame 4 and which nests around the front of prime mover 8. Support assembly 33 includes spaced left and right U-shaped support beams 34 that are fixed to loader frame 4 by mounting plates 36. Each mounting plate 36 carries outboard of its support beam 34 an enclosed pocket 38 that is open towards the rear and carries a pivot pin 40 therein. Pivot pins 40 in pockets 38 pivotally journal the base ends of hydraulic cylinders 30 used for lifting and lowering linkages 18.

[0031] Referring further to FIG. 4, each support beam 34 comprises spaced side walls 42 connected together by a front wall 44 to provide strength. The rear ends of support beams 34 are open for receiving therebetween and pivotally mounting the front ends of the two lower loader arms 22, 24. Support beams 34 are united by a top cross rod 42 shown in FIG. 1 and by a partial front cross wall 45 shown in FIG. 4. The ends of cross rod 42 extend into the interior of the tops of support beams 34 and pivotally journal the front ends of lower loader arms 22 for rotation about the horizontal axis x.sub.1. The front ends of the other pair of lower loader arms 24 also extend into the interior of support beams 34 and are pivotally journalled therein for rotation about the horizontal axis x.sub.2.

[0032] In addition to the strength provided by support assembly 33, the lower loader 22 arms that pivot around axis x.sub.1 comprises cast steel arms that are welded to a rectangular cross beam 46. Top and bottom gussets 48 and 50 are further welded between the front ends of lower loader arms 22 and the tops and bottoms of cross beam 46 at each end thereof. This provides very high strength to the pair of lower loader arms 22 particularly given the mounting of lower loader arms 22 inside the U-shaped support beams 34 of support assembly 33. Moreover, the other pair of lower loader arms 24 also comprises cast steel arms and also pivotally mounts inside the U-shaped support beams 34 of support assembly 33 to pivot around axis x.sub.2 in FIG. 4. Note that the other pair of lower loader arms 24 is not shown connected in FIG. 4 to support assembly 33, but have bores 52 at the front ends thereof that would be pivotally journalled on pivot pins (not shown) provided in support beams 34 on axis x.sub.2.

[0033] Looking at the exploded portion of loader arm assembly 14 that is shown in FIG. 4 above the fixed support assembly 33, it can be seen that upper loader arms 20 also have a box-shaped beam configuration formed by side walls 54 connected together by a top wall 56. The bottom of each upper loader arm 20 is open to receive therein the end of piston rod 32 and the rear ends of lower loader arms 22, 24 for pivotal attachment thereto. The strength of upper loader arms 20 is increased by a rectangular box beam 58 of substantial size that connects upper loader arms 20 towards the front thereof. This box beam also serves to mount a hydraulic cylinder 60 that pivots dump bucket 16 at the front of upper loader arms 20.

[0034] Together, the configuration of support assembly 33, the configuration of the pairs of lower loader arms 22, 24 and how they are pivotally journalled at their front ends inside the U-shaped support beams 34 of support assembly 33 and at their rear ends inside the U-shaped upper loader arms 20, and the box shaped beam configuration used to form upper loader arms 20 along with box beam 58 that unites such loader arms 20, provide a loader arm assembly 14 having sufficient strength and durability to withstand the loads and stresses involved in high lift operations of heavy loads. This is all accomplished in a loader arm assembly 14 that neatly and compactly nests around prime mover 8 in its lowermost, fully retracted position shown in FIG. 2. In this regard, hydraulic cylinders 30 extend straight rearwardly as they connect between the side pockets 38 of support assembly 33 and the undersides of upper loader arms 20. To avoid hitting or interfering with such hydraulic cylinders 30, the lower of the two pairs of lower loader arms, namely loader arms 24 that pivot about the axis x.sub.2, are curved to the side to miss hydraulic cylinders 30 as best shown in FIG. 5. Thus, loader arm assembly 14 is well adapted to the loads it must carry during high lift operations while being tailored to the small form of a compact utility loader 2. In addition, high lift loader arm assembly 14 maintains the forward reach of the loader arms 20 and dump bucket 16 carried thereon far better than radial loader arms which move somewhat rearwardly as they rise.

[0035] Turning now to FIGS. 6-13, another aspect of this invention relates to the traction control levers 62 that cause differential and spin steering of the traction drive of loader 2. As is well known in skid steer and compact utility loaders, individual drives, such as but not limited to hydrostatic drives, are provided on each side of loader 2 to effect both propulsion and steering of loader 2. This is done by differentially actuating the drives to each side of loader 2, namely causing one drive to rotate faster than the other, to create turns to the side of the slowest drive. Spin or zero radius turns are accomplished by causing one drive to rotate forwardly at a given speed while causing the other drive to rotate rearwardly at approximately the same speed. As noted above, such differential drives are in themselves well known for use on compact utility loaders.

[0036] As best seen in FIG. 7, known differential drives are often controlled by the operator by using side-by-side control levers 62 that may be operated along fore and aft axes to be pushed forwardly out of neutral or pulled rearwardly out of neutral. Levers 62 often have a partially spherical ball or knob 64 on the top thereof. Levers 62 are shown in neutral in FIG. 7. When they are pushed forwardly as indicated by the arrows A in FIG. 7, loader 2 is propelled forwardly. When they are pulled rearwardly as indicated by the arrows B in FIG. 7, loader 2 is propelled in reverse. If levers 62 are advanced or retarded unequally as they are pushed forwardly or pulled rearwardly, this differential action between levers 62 causes turns to one side. The operator normally rests one hand on such levers 62 when driving loader 2 and uses the fingers of his or her hand to feather one lever 62 more forward or rearward of the other lever 62 when turning. Grab bars 66 are provided in front of and in back of levers 62 for allowing the user to rest portions of his or her hand or fingers on grab bars 66 when operating levers 62.

[0037] This invention further provides a unifying hand grip 70 that sits atop levers 62 and effectively unites levers 62 when hand grip 70 is installed. As shown in FIG. 7, hand grip 70 is provided in two halves 72 that may be separated from one another for installation of hand grip 70. Various threaded screws 74 are provided for allowing halves 72 to be joined to another. When halves 72 are installed around the front and rear sides of knobs 64 of levers 62 such that the parting lines of halves 72 are abutted with one another, screws 74 may be installed and tightened to finish the installation of hand grip 70 atop levers 62. The installed hand grip 70 is shown in FIG. 6.

[0038] Referring now to FIGS. 8 and 9, halves 72 define two laterally extending slot halves 76 on either side of the centerline 77 of hand grip 70. When halves 72 are united together, slot halves 76 form laterally extending slots 78 on either side of hand grip centerline 77. The front and rear sides of slots 78 are curved to mate with the spherical curvature of the front and rear sides of knobs 64 of levers 62. Once assembled, knobs 64 of levers 62 are received in slots 78 but cannot be pulled downwardly out of slots 78 as the spherical shapes of knobs 64 are larger than the bottom openings of slots 78 through which the very lowermost portions of knobs 64 extend. Thus, once halves 72 are assembled around knobs 64 of levers 62, hand grip 70 formed thereby cannot be removed from knobs 64 except by disassembling the same into halves 72 thereof.

[0039] As shown in FIG. 10, the top of each knob 64 is cut away or truncated to expose a hollow central cavity 80 of knob 64 to allow knob 64 to be attached to a threaded upper end 82 of its corresponding lever 62. A nut (not shown) is received on threaded upper end 82 and screwed downwardly to secure knob 64 to lever 62. Preferably, the nut bottoms out in cavity 80 at a point at which knob 64 has no substantial vertical movement relative to lever 62 but before knob 64 is immovably or completely clamped or tightened to lever 62. Some degree of relative rotation or spinning of knob 64 atop lever 62 is preferred since such relative rotary motion has been found to reduce friction and wear as knob 64 traverses the length of slot 78 in which it is received with the caveat that knob 64 should not be so loose atop lever 62 that it moves up and down in any significant fashion on lever 62. While such relative rotary motion is preferred, knob 64 could be made fast with lever 62 so as to preclude such relative rotary motion if so desired.

[0040] In addition as further shown both in FIG. 8 and FIG. 10, while most of the surface of knob 64 is spherical in shape, the lower portion of knob 64 has a conical collar 65 leading to its bottom surface. This conical collar 65 is opposed by an approximately vertical wall 77 at the bottom of the front and rear sides of slot 78 which wall 77 is located below and cuts off the curved front and rear sides of slot 78 which match to the spherical portion of knob 64. Thus, a triangular gap 84 is located between the front and rear sides of slot 78 at the bottom thereof and the front and rear sides of conical collar 65. This triangular gap 84 has an apex 85 that forms a relatively sharp break or line of contact between conical collar 65 and walls 77 that ensures that hand grip 70 will not rock back and forth atop knobs 64 when it is pushed straight forwardly or pulled back straight rearwardly for straight line forward or reverse travel. This helps hand grip 70 remain stable and firm atop knobs 64 without having a tendency to itself rotate around the spherical surfaces of knobs 64.

[0041] Hand grip 70 eases the task of manipulating levers 62. To go forwardly, the operator simply pushes forwardly on hand grip 70. To go rearwardly, the operator simply pulls back on hand grip 70. To steer to the left when traveling forwardly, the operator simply rotates or cocks his or her hand to the left to cause the right side of hand grip 70 to move forwardly and the left side of hand grip 70 to move rearwardly. This automatically creates the proper differential action between levers 62 to cause a left turn. Slots 78 in hand grip 70 permit hand grip 70 to slide and pivot as need be around knobs 64 of levers 62 to accommodate this hand grip twisting or cocking to one side or the other. Put another way, since levers 62 and their knobs 64 can only move fore and aft in straight lines, slots 78 are needed to effectively allow hand grip 70 to have lateral motion relative to knobs 64 when hand grip 70 is being used to execute turns.

[0042] FIGS. 12 and 13 show hand grip 70 being used to execute a spin or zero radius turn towards the left. Hand grip 70 will have moved from the position shown in FIG. 9 where knobs 64 are located on the inner ends of slots 78 in each side of hand grip 70 to the positions shown in FIGS. 12 and 13 where knobs 64 will have moved to the outer ends of slots 78. Note in FIG. 12 that the same conical collar 65 and vertical wall 77 is used at the outer ends of slots 78 to allow knobs 64 to move into the outer ends of slots 78 without levers 62 being obstructed or hitting the outer ends of slots 78. As shown in FIG. 11, Applicants have found it useful to shape each slot 78 in an egg-shaped form where the inner end 90 of each slot 78 is somewhat smaller than the outer end 92 of each slot. The increase in size in outer end 92 of each slot 78 permits knobs 64 to more easily move the entire length of the slots when doing spin or zero radius turns without binding.

[0043] Using a hand grip 70 of the type shown in FIGS. 6-9 is far easier than trying to control both traction control levers with the fingers of the user's hand. Accordingly, hand grip 70 significantly increases the ease by which the operator is able to control the traction drive system of loader 2. This in turn increases safety and makes it less likely for the operator to have imprecise turns or to lose any steering control.

[0044] Various modifications of this invention will be apparent to those skilled in the art. For example, unifying hand grip 70 would be useful on outdoor work vehicles other than compact utility loaders as long as such work vehicles have a differential drive and steering system operated by dual traction control levers. Accordingly, the scope of this invention is to be limited only by the appended claims.