Utility Hauling Vehicle Having Four Wheel Drive

The present invention relates to a multiple wheeled hauling vehicle and more specifically relates to a four wheel drive vehicle capable of hauling modest size loads over a variety of terrain.

Three and four wheeled recreational vehicles designed for so-called all terrain use have become quite popular over the past ten to fifteen years. For the most part, these vehicles are designed just for carrying the rider, however some have been adapted for carrying additional loads by adding load carrying boxes and racks thereto. While these load carrying adaptations have increased the utility of these vehicles, the loads they are capable of bearing are quite small and the loading of some of the vehicles can adversely affect their handling and stability.

According to the present invention, there is provided an improved utility hauling vehicle.

A broad object of the invention is to provide a utility hauling vehicle having the capacity for hauling heavier loads than prior art three and four wheel utility vehicles of the same power class without sacrificing handling or stability characteristics.

Another object is to provide a utility hauling vehicle having four wheel drive, all terrain traversing capability and the ability to make relatively short turns without scrubbing or marring lawn grass and the like.

A more specific object is to provide a hauling vehicle having a rigid frame, at least one steerable front wheel suspended from the front of the frame, front and rear, unsuspended pairs of drive wheels mounted in tandem to said frame and each pair of drive wheels being differentially driven, all wheels being of the low pressure high flotation type, and the vehicle having a load carrying zone substantially confined to the vertical projection of the area containing said drive wheels.

Another object is to provide a utility hauling vehicle as set forth in the previous object designed such that weight is transferred to the rear pair of drive wheels so that during turning of the vehicle scrubbing by the front pair of drive wheels is minimized.

Still another object of the invention is to provide a utility hauling vehicle having front and rear pairs of differentially driven drive wheels as set forth hereinabove and to further provide a differential lock device which locks the rear pair of drive wheels for rotation in unison which results in the front pair of drive wheels also being locked for rotation in unison.

Yet another specific object is to provide a differential lock device which is in the form of a standard jaw clutch and controls for engaging and disengaging said clutch.

These and other objects will become apparent from a reading of the following description together with the appended drawings.

FIG. 1 is a left side elevational view of a utility hauling vehicle constructed in accordance with the present invention.

FIG. 2 is a top plan view, with portions broken away, of the vehicle shown in FIG. 1.

FIG. 3 is a rear view of the vehicle shown in FIG. 1.

FIG. 4 is a somewhat schematic view of the rear portion of the vehicle drive train and controls therefor, and with the combined reverser and differential transmission being shown in vertical cross section.

FIG. 5 shows a variation of the forward end of the vehicle shown in FIG. 1 wherein two steerable wheels are used instead of one.

FIG. 6 shows a variation of the vehicle shown in FIG. 1 wherein the front, drive axle means is located at a level above the rear drive axle means for the purpose of having the rear drive wheels bear a greater proportion of the vehicle load than the front drive wheels.

FIG. 7 is a table demonstrating the effect the weight transfer means has in placing more weight on the rear pair of drive wheels than on the front pair of drive wheels.

Referring now to FIGS. 1-3, there is shown a utility hauling vehicle 10 including a rigid frame 12 supported by a front pair of unsuspended, right and left drive wheels 14 and 16, respectively, a rear pair of unsuspended, right and left drive wheels 18 and 20, respectively, and by a suspended, steerable front wheel 22. The pair of wheels 18 and 20 are mounted as close as is practical to the pair of wheels 14 and 16 in order to keep the turning radius of the vehicle at a minimum. Also, the wheels 14-22 are preferably of a low pressure (1-8 psi, for example) high flotation design for aiding in good stability and steering characteristics as explained in more details below.

The main frame 12 includes a plurality of tubular members welded together to form a box-like rear section 24 located between the front and rear pairs of drive wheels and a front section 26 which, in top view converges forwardly from the rear section. A front pair of right and left axle support structures 28 and 30, respectively, is fixed to and projects transversely from opposite lower side locations of the rear frame section 24 and spaced rearwardly of the structures 28 and 30 and similarly fixed to opposite lower side locations of the rear frame section is a rear pair of right and left axle support structures 32 and 34, respectively. The front drive wheels 14 and 16 are respectively fixed to the outer ends of front right and left drive axle sections 36 and 38, the latter being rotatably supported by bearings carried by the rear frame section and the front pair of axle support structures. Similarly, the rear drive wheels 18 and 20 are respectively fixed to the outer ends of rear right and left drive axle sections 40 and 42, the latter being rotatably supported by bearings carried by the rear frame section and the rear pair of axle support structures.

The front frame section 26 includes a lower structure which forms a horizontal engine support platform 44 and an upper structure which forms a slightly upwardly and forwardly inclined operator support platform 46. Continuing forwardly from the platform 44 is a steeply inclined structure 47 which together with the forward end of the platform 46 is joined to an upright cylindrical tube forming a steering spindle housing 48. A structure mounting the front wheel 22 for movement about the axis of the housing 48 for steering the vehicle 10 includes a pair of generally L-shaped tube members 50 and 52 joined in spaced, side-by-side relationship and having upper and lower flanges 54 and 56 secured thereto and disposed at the upper and lower ends of the housing 48. A steering spindle or pin 58 extends through the flanges and housing. A handle bar 60 is fixed to the tops of the members 50 and 52 and has the usual grips at its opposite ends. A U-shaped wheel mounting link 62 is vertically pivotally mounted to the lower ends of the members 50 and 52 by a structure including a transverse, cylindrical tube 64 welded to the bight portion of the link 62 and a pivot pin 66 extending through the members 50 and 52 and received in the tube 64. The front wheel 22 is located between the opposite legs of the link 62 and is rotatable about an axle structure 68 extending between and secured to forward ends of said link. A pair of brackets 70 is respectively fixed to the opposite legs of the link 62 and a pair of brackets 72 is located at the junctures of each leg portion forming the L-shaped members 50 and 52. A pair of shock absorbers 74 and 76 is respectively coupled between the pairs of brackets 70 and 72. The shock absorbers 74 and 76 are each pre-loaded in the downward direction so as to urge the link 62 and hence the wheel 22 downwardly against the ground and act to transfer the weight of the vehicle and any load borne thereby to the rear wheels 18 and 20 for a reason discussed in more detail below. Adjustment of down pressure is made possible by additional mounting holes 78 provided in the brackets 70. Alternate or additional adjustment may be accomplished by providing shock absorbers having springs that are adjustable as is well-known in the art.

Overlying and mounted to the operator support platform 46 is a molded plastic structure 79 including a rear portion defining right and left fenders 80 and 82 respectively located forwardly of the front drive wheels 14 and 16. The fenders 80 and 82 are each fastened to the back side of a horizontal transverse box support member 84 extending substantially the full width of the vehicle. An operator's seat 86 is located on top of the plastic structure 79 and is mounted to the support platform 46. A horizontal foot rest 88 is secured to the bottom of the engine support platform 44.

The vehicle 10 is powered by an internal combustion engine 89 mounted to the platform 44 just behind a battery 90. Fuel for the engine 89 is carried by a fuel tank 91 strapped down against horizontal cross members extending between opposite sides of the frame section 14.

The engine 89 has an output shaft (not shown) projecting from its left side. A gear case or housing 92 of a combined reverser and differential transmission is mounted to the rear frame section 24. Referring now also to FIG. 4, it can be seen that journalled in an upper location of the case 92 is an input shaft 98 below which is journalled an intermediate shaft 100. The front right and left drive axle sections 36 and 38, respectively, have inner end portions supported in a lower part of the case 92. Power is delivered to the input shaft 98 by a torque converter drive including a drive pulley 106 coupled to the engine output shaft, a driven pulley 108 coupled to a leftward projection of the input shaft 98 and a drive belt 110 trained about the pulleys 106 and 108. Rotatably mounted on the input shaft 98 respectively adjacent right and left walls of the case 92 are a forward drive pinion 112 and a rearward drive sprocket 114. The forward drive pinion 112 is meshed with a gear 116 fixed on the intermediate shaft 100 while the reverse drive sprocket 114 is coupled, as by a drive chain 118 to a sprocket 120 fixed on the shaft 100. Fixed for rotation with, but for axial movement along the input shaft 98 at a location between the pinion 112 and sprocket 114 is a forward-reverse shift collar 122. The right and left faces of the collar 122 are respectively provided with sets of drive lugs 124 and 126 for selective engagement with similar sets of drive lugs 128 and 130 respectively provided on the hubs of the pinion 112 and sprocket 114. The collar 122 is selectively shifted between forward and reverse drive establishing positions by a controller including a vertical shaft 132 rotatably mounted in the case 92 and to which is fixed an output arm 134 which carries a pin 136 located within an annular groove 138 provided in the collar 122. An input arm 140 is fixed to the top of the shaft 132 and is linked to a fore-and-aft extending control rod 142 that is pivotally mounted, as at 144 to the rear frame section 24 and terminates forwardly in an out-turned handle 146. A disc brake assembly 148 includes a disc 150 mounted on the right end of the intermediate shaft 100 and a hydraulically operated caliper 152 is mounted to the frame section 24 in straddling relationship to the disc 150 for selectively applying a braking force thereto.

An output pinion 154 is fixed for rotation with the intermediate shaft 100 and is meshed with an output gear 156 forming part of a differential 157 having a set of bevel gears 158 splined to respective inner ends of the front right and left drive axle sections 36 and 38. Thus, the front pair of drive wheels 14 and 16 may rotate relative to each other in the absence of the differential action being locked in a manner described below. The right front axle section 36 is coupled for driving the right rear axle section 40 by means of drive sprocket 159 fixed to the axle section 36, a driven sprocket 160 fixed to the axle section 40 and a drive chain 162 trained about the sprockets 159 and 160. A chain tensioner 164 (FIG. 2) is vertically adjustably mounted to the frame section 14 and engaged with a lower run of the chain 162. Similarly, the left front axle section 38 is coupled for driving the left rear axle section 42 by means of a drive sprocket 165 fixed to the axle section 38, a driven sprocket 166 fixed to the axle section 42 and a drive chain 168 trained about the sprockets 165 and 166. A chain tensioner 170 is provided for keeping the chain 168 properly tensioned.

A differential lock 172 in the form of a jaw clutch assembly is provided for locking the right and left rear axle sections 40 and 42 for rotation together, which, by virtue of the drive chains 162 and 168 results in the front axle sections 36 and 38 also rotating in unison. Specifically, the differential lock 172 includes an axially fixed clutch jaw 174 splined to an inner end of the left axle section 42 and a clutch jaw 176 splined for rotation with, but axial movement along an inner end portion of the right axle section 40. The jaw 176 includes a hub 178 provided with an annular groove 180 having a slip yoke band 182 received therein and provided with diametrically projecting pins 184 (only one shown). A control lever 186 is pivotally mounted, as at 188, to the rear frame section 24 and has a yoke 190 at its lower end, the yoke having notched legs 192 straddling the shiftable clutch jaw 176 and receiving the pins 184. A first tension spring 194 is coupled between an upper end of the lever 186 and the rear frame section 24 and normally biases the shiftable clutch jaw 176 rightwardly to an unlocked position wherein clutch jaws 174 and 176 are separated from each other. A second tension spring 196 has one end coupled to the upper end of the lever 186 in opposition to the spring 194 and another end coupled to an end of a control cable 198. The control cable 198 passes over a guide pulley 200 mounted to the right side of the rear frame section 24 and has another end coupled to a differential lock control pedal 202 pivotally mounted to the right side of the operator foot rest 88 (FIG. 2). The spring 196 is stiffer than spring 194 and when an operator presses down on the pedal 202, the lever 186 will be pivoted against the bias of the spring 194 and will act to effect engagement of the clutch jaws 174 and 176, as shown in FIG. 4. Should the clutch jaws 174 and 176 initially be misaligned, the cable 198 will act to stretch the spring 196 which then acts to bias the jaw 176 toward the jaw 174 so as to effect their inter-engagement once they do become properly aligned. The differential lock 172 thus remains engaged only so long as an operator depresses the pedal 202.

The vehicle 10, as viewed in plan view, includes a load carrying zone which is substantially confined to a zone circumscribed by the vertical projection of an area circumscribing the drive wheels 14--20. In other words, the zone has a width approximately equal to the distance between the outer faces of the right and left drive wheels and having a length approximately equal to the distance between the frontand rearmost portions respectively of the front and rear pairs of drive wheels. The confinement to this zone of loads hauled by the vehicle is important since it ensures that the handling or stability characteristics of the vehicle will not be negatively influenced as is the case with prior art vehicles having substantial loads located substantial distances rearwardly or outwardly of the support wheels. It is here noted, however, that apparatus mounted to the vehicle 10 within said zone may have parts extending substantially beyond the zone without adversely effecting the handling or stability characteristics of the vehicle if such parts have a weight which is insignificant when compared to the total weight of the apparatus. A sprayer having a fluid containing tank and pump located within the zone and having a boom extendible beyond the zone is an example of such an apparatus.

In the disclosed embodiment, an open top box 204 is provided for containing a load to be hauled. The box 204 normally rests on top of the rear frame section 24 and the transverse box support member 84 of the front frame section 26. A rear bottom portion of the box 204 is coupled, as at 206, to an upper rear portion of the rear frame section 14 for pivoting about a horizontal transverse axis to aid in dumping its contents. A prop rod 208 is pivotally mounted to a forward underside location of the box and is adapted to be pivoted to a vertical prop position, as shown in broken lines in FIG. 1, wherein the lower end thereof is received in a socket 210 provided on the rear frame section 24. A pair of elastic hold-down straps 212 is mounted to the rear of the support platform 46 adjacent the forward end of the box 204 and is releasably received in catches 214 provided at the forward side of the box 204. In addition to hauling a load contained in the box 204 or otherwise secured in the load hauling zone of the vehicle, the vehicle may pull a load through means of a hitch 216 fixed to a central rear location of the rear frame section 24.

The weight transfer characteristic of the vehicle 10 shown in FIGS. 1-4 is made apparent by the table shown in FIG. 7 which contains the load measured at each of the wheels of such a vehicle for various loads carried by the vehicle. The vehicle used in the measurements had an empty weight of approximately seven hundred ten pounds and all measurements were made with the vehicle located on a level surface. As indicated by the vehicle diagram located above the table, the front steerable wheel is designated by F, the right and left front drive wheels are respectively designated by RF and LF, and the right and left rear drive wheels are respectively designated by RR and LR. The operator is designated by the letter O while the payload placed in the box is designated by the letter P.

The designed payload capacity of the vehicle used in the measurements was eight hundred pounds. The loads on the vehicle wheels were first measured without a payload and with no operator on board. Next loads were measured with the operator seated and then loads were measured as payloads in increments of one hundred pounds were added until the designed capacity was reached. Using the measured loads, it can be seen that the front set of drive wheels never support more than about thirty percent of the total weight carried by the vehicle while the rear set of drive wheels support up to about fifty three percent and the front steerable wheel supports the remaining weight. Thus, the table demonstrates the weight transfer characteristic of the vehicle which results in the front set of drive wheels supporting a significantly lesser amount of the weight of the vehicle, operator and payload than is carried by the rear set of drive wheels.

The operation of the embodiment of the vehicle 10 illustrated in FIGS. 1-4 is briefly as follows. Assuming normal, good tractive conditions, the vehicle 10 will be operated with the differential lock 172 disengaged so that relatively sharp turns can be made when desired. It has been observed that during such turns the low pressure, high flotation wheels deflect and roll sideways on the earth without skidding thus resulting in very little scrubbing or marring of the ground which is a very important characteristic when operating on lawn grass, for example. This characteristic is further enhanced by the fact that the frame 12 is rigid and the suspension for the front wheel 22 acts to lift up on the front of the frame 12 so as to transfer weight to the rear drive wheels 18 and 20. The vehicle 10 then turns somewhat like a three wheeled vehicle, and because they are not so heavily loaded, any skidding done by the front pair of drive wheels 14 and 16 will result in only minimal earth surface damage.

If the vehicle should encounter a relatively steep hill or muddy conditions, for example, additional traction can immediately be made available by locking out the differential action. An operator can easily accomplish this by pressing down on the pedal 202 with his foot to cause the cable 198 to pull on the lever 186 against the action of the spring 194 resulting in the clutch jaw 176 being moved into engagement with the clutch jaw 174 and thus in the axle sections 40 and 42 being fixed for rotating together. The chains 162 and 168 are then driven in unison to cause the axle sections 36 and 38 to be likewise driven in unison. As soon as the terrain characteristic requiring the additional traction is traversed, the operator releases his foot from the pedal 202 and the spring 194 acts to disengage the clutch jaws 176 and 178 from each other.

Because the load bearing zone of the vehicle 10 does not overhand the drive wheels 14-20 and the latter present a relatively large "footprint", the vehicle is exceptionally stable.

Although the resulting steering radius would be larger than that of the vehicle 10 for some uses it may be necessary to use a modified version of the vehicle 10 which has two steerable front wheels. Thus, referring now to FIG. 5, there is shown the front end of a vehicle 10' which is just like the vehicle 10 shown in FIGS. 1-3 except that it employs a rigid frame 12' having a front frame section 26' designed for supporting a pair of steerable wheels instead of only one steerable wheel. Specifically, the front frame section 26' is not tapered forwardly, as is the frame section 26, and vertically pivotally mounted to right and left sides thereof, as at horizontal, longitudinal pivots 220 and 222, are right and left pairs of triangular shaped wheel support link assemblies 224 and 226, respectively. The link assemblies 224 and 226 respectively carry swively mounted, wheel support axles (only the right axle 228 being shown). Mounted to these axles is a pair of front wheels 230 (only the left wheel is shown). A steering linkage 232 is coupled between the lower end of a steering post 234 journalled in the frame section 26' and turnable through means of a handle bar 60'. A pair of shock absorbers 74' and 76' are coupled between the frame section 26' and the pair of wheel support link assemblies 224 and 226. Like the shock absorbers 74 and 76 in the first described embodiment, the shock absorbers 74' and 76' act to force the pair of front wheels 230 downwardly which results in the lifting of the forward end of the rigid frame 12' and hence in weight being transferred to the rear drive wheels of the vehicle.

Another method of transferring weight to the rear drive wheels alone or in conjunction with the front wheel suspension is illustrated in FIG. 6. Specifically, in FIG. 6, it can be seen that the front drive wheels are mounted to the rear frame section 24 for rotation about an axis X which is located a distance d above the level of the rear drive wheels. Thus, it will be understood that the first increment of weight of any load placed on the vehicle will first be borne by the front wheel and rear pair of drive wheels.