Some aspects of this invention are limited to chain o belt driven mechanisms but other aspects may be utilized i shaft driven mechanisms. Furthermore this invention has particular application to ride-on mowers and the like vehicles and in particular reversible belt drive mechanisms therefore and for illustrative purposes reference will be made hereinafter to such application. However it is to be understood that aspects of this invention may be utilized in other forms of vehicles and drives such as .in golf buggies and small vehicles.

Ride-on mowers often utilize reversible belt drive assemblies of the type illustrated in my earlier Australian Patent Specification No. 402230 in which opposed clutch plates of a clutch assembly are adapted to be reciprocated along an output shaft by a clutch actuating mechanism for engagement with either one of a pair of belt driven contra- rotatable pulley wheels. The latter are supported for free rotation on the output shaft and are coupled thereto through the clutch assembly for driving engagement in forward or reverse rotation. The pulley wheels may be driven from a common belt or separate belts. As illustrated in my earlier Australian Patent Specification No. 402230 the pulley wheels are rotated by opposite runs of a V-section drive belt extending between an idler pulley elevated above the mower chassis and a driving pulley on or driven from the mower's motor. A cutter drive belt passes between a pulley on the cutter housing and a pulley on the motor. The cutter drive belt extends about a pair of idler pulleys at the front of the mower whereby the drive may be transferred from the engine pulley to the horizontally displaced cutter housing pulley. Such drives have been incorporated in ride-on mowers to provide a reversible drive to the rear wheels. The clutch plates are actuated by a rocking type pedal in which heel pressure is used to engage one clutch plate for reverse drive

and toe pressure is used to engage the opposite clutch plate for forward drive.

Typically, in ride-on mower applications of the reversible belt drive mechanism, the chassis is formed as a sheet metal pressing and the clutch actuating mechanism includes a linkage assembly which interconnects the foot actuated pedal to the clutch for reciprocating same along the supporting shaft. It will be appreciated that the power transferred through the clutch is proportional to the engagement force between the respective clutch plate and driving pulley wheel of the reversible belt drive mechanism. Accordingly, any flexing which occurs either in the linkage assembly or the chassis is detrimental to the performance of the reversible belt drive mechanism. Furthermore the actuating mechanisms utilised to date for actuating the clutch have hampered the ability to quickly install or remove the reversible belt drive mechanism from the chassis for servicing purposes.

Furthermore, as the width of mowers and other small vehicles, such as golf buggies increase the disadvantages inherent in such drive systems becomes more noticeable. Such disadvantages can be overcome to a large extent by the provision of a differential in the drive train to the rear wheels. Unfortunately the differentials available to date have not suited the simple drive trains which are utilised in most mowers and small vehicles and additionally such differentials have not had the ability to be selectively utilised or locked.

The present invention aims to alleviate the abovementioned disadvantages and to provide improvements to drive mechanisms and in particular to -reversible belt drive mechanisms which will be reliable and efficient in use. This invention also aims to alleviate the abovementioned disadvantages and to provide improvements to ride-on mowers and other small vehicles which will be reliable and efficient in use. Other objects and advantages of this invention will hereinafter become apparent.

With the foregoing and other objects in view, this invention in one aspect resides broadly in a reversible drive

SUBSTITUTE SHEET

assembly including a pair of wheels supported on a output shaft at opposite sides of a clutch assembly and adapted to be driven for contra rotation and clutch actuating means for moving the clutch assembly into engagement with either drive wheel for rotation therewith in a forward or reverse direction, the actuating means including an actuating member restrained for movement substantially along the longitudinal axis of the output shaft.

Preferably the actuating member is actuated through a linkage adapted to guide the actuating member for movement substantially along the longitudinal axis of the output shaft. It is also preferred that the actuating member be readily detachable from the linkage to facilitate operative placement of an endless belt about the drive wheels and or removal of the reversible belt drive assembly from its supporting chassis.

In a preferred form the actuating member passes between the drive wheels and beyond the extremities thereof whereby the opposite ends of the actuating member may be connected to respective links of the linkage. The links may be in the form of lazy links and an independent operating member may be used to operate the actuating member or the links may be active members used to transmit the actuating force to the actuating member. For example the links may be so disposed that the operating means moves the actuating member transverse to the drive shaft in order that the linkage restrains the actuating member for movement whereby it has a component of motion along the axis of the drive shaft. Preferably however the links extend from the actuating member to respective movement translation means, such as bell cranks, wedges or cranks or the like. The latter may be actuated by a driver's control member such as a foot pedal or control lever.

Suitably the links are disposed substantially parallel to the drive shaft but of course they could diverge from actuating member relative to the drive shaft. Preferably the actuating linkage interconnecting the driver's control member to the actuating member incorporates limiting means for limiting the initial engagement pressure between the clutch

^?

assembly and a respective pulley wheel. The limiting means may be in the form of a spring which controls the maximum or initial engagement pressure of the respective clutch plate or the limiting means may be in the form of a damper which damps initial engagement of the clutch assembly with the engaged pulley wheel. Alternatively the limiting means may be a spring or the like associated with the foot control pedal and adapted to resist foot pressure so that only a relatively small actuating force is transferred through to the clutch actuating means.

Preferably, the limiting means is incorporated in the actuating linkage interposed between a rocking type foot actuating pedal and the actuating means which engages the clutch assembly and moves the latter between the spaced pulley wheels. Accordingly, the limiting means may be in the form of a bell crank assembly having angularly disposed pivot arms resiliently connected to one another so as to minimize the engagement force which may be applied through the bell crank assembly. In another aspect, this invention resides broadly in a chassis mounting arrangement for a reversible belt drive assembly of the type including a pair of drive wheels supported on a output shaft at opposite sides of a clutch assembly and adapted to be belt driven for contra rotation and clutch actuating means for moving the clutch assembly into engagement with either drive wheel for rotation therewith in a forward or reverse direction, characterised in that the drive assembly is mounted in an aperture in a sheet metal portion of a chassis by drive shaft bearings mounted on flanges extending along edges of the sheet opening whereby the drive shaft axis is disposed closely adjacent the apertured sheet metal portion.

Preferably the drive from the shaft is transmitted from a sprocket disposed intermediate one drive shaft bearing and the drive assembly, it is also preferred that the sheet be cutaway or indented along the opening edge adjacent the bearing mounts to permit the bearings or their carriers to extend to opposite sides of the sheet and thereby permit the centreline of the drive shaft to be maintained close to the

SUBSTITUTE SHEET

sheet portion. Alternatively, the flanges may be so forme as to permit the shaft axis to supported in line with th sheet. For example, the flanges at opposite sides of eac bearing at each opening edge could extend to opposite sides of the sheet to permit diagonally opposed bearing mounts t support a flangette bearing or the like at opposite sides of the sheet. Alternatively a separate bearing carrier could be fixed to the sheet to hold the bearings in their desired positions. In yet another aspect, this invention resides broadly in a differential assembly including:- an axle assembly; a fixed wheel mount at one end of the axle assembly; a free wheel mount including a tubular stub axle supported about the opposite end of the axle assembly; a fixed sun gear on the axle assembly and preferably located adjacent the free wheeling mount; a gear case assembly having planetary gears therein adapted to engage with said fixed sun gear; mounting means for mounting the gear case rotatably about the axle assembly; drive means preferably adapted for belt or chain drive from a drive motor for rotating the gear case about the axle; a further sun gear adapted to mesh with said planetary gears to form a differential drive, and connector means for connecting the free wheel mount to the further sun gear. The term fixed wheel mount and free wheel mount herein are to be understood as being fixed of free relative to the innermost one of the concentric axles. The fixed sun gear may be disposed adjacent the free wheel mount or it may be disposed adjacent the fixed wheel mount. Alternatively the sun gear and the differential assembly could be disposed centrally of the axle assembly or substantially within a wheel hub. The gear case may be of conventional form and it may include an end flange and axle locating means for locating the planetary gears with respect to the sun gear. Preferably however the housing is an open ended housing which is operatively located in position by meshing of the respective gears and end plates are provided

which may be through bolted to clamp the housing in position. Suitably one end plate is constituted by the web portion of a sprocket or pulley wheel.

The sun gears and the planetary gears could be formed as spur gears with inter-engagement between sun gears being provided with at least one pair of enmeshed contra-rotating spur gears axially displaced along one another and each having a free end portion which meshes with a respective sun gear. In a further aspect, this invention resides broadly in a differential assembly including:- an axle assembly; a fixed wheel mount at one end of the axle assembly; a free wheel mount including a tubular stub axle supported about the opposite end of the axle assembly; a fixed sun gear on the axle assembly; a gear case assembly having planetary gears therein adapted to engage with said fixed sun gear; mounting means for mounting the gear case rotatably about the axle assembly; drive means for rotating the gear case about the axle; a further sun gear adapted to mesh with said planetary gears to form a differential drive; connector means for connecting the free wheel mount to the further sun gear, and selectively operable locking means for locking the axle to the free wheel mount.

Suitably the axle extends outwardly beyond the free wheel mount and the locking means is in the form of a dog clutch having respective clutch portions mounted on the free wheel mount and the extension of the axle therebeyond. Suitably the dog clutch is in the form of a carrier mounted non-rotatably on the extension portion and moveable therealong for engagement with the corresponding dog clutch portion on the free wheel mount. Alternatively the tubular stub axle could be made with apertures to correspond with an aperture in the axle and locking could be accomplished by inserting a pin to pass through the coincident apertures. Alternatively the axle may be provided with a pawl or dog or

T TE SHEET

like member which may be supported in the axle and selectively moved radially outwards to engage a recess in the inner surface of the tubular stub axle.

In yet a further aspect, this invention resides broadly in a drive axle assembly including:- axle means having respective wheel mounts at opposite ends thereof and spaced chassis mountings intermediate said wheel mounts and through which the axle means is attached to a chassis; a differential operatively connected to a power source and to said wheel mounts and being disposed intermediate one wheel mount and the adjacent chassis mounting.

The differential may be of a conventional form and be provided with a differential casing and axle housings or it may be in the form defined above. Suitably however the differential is adapted to be so arranged that it is substantially concealed within the adjacent wheel and is exposed when the wheel is removed for servicing or the like.

In order that this invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate a typical embodiments of the present invention and wherein:-

FIG. 1 illustrates a mower assembly according to this invention FIG. 2 is a pictorial view of a drive arrangement of the mower assembly illustrated in FIG. 1;

FIG. 3 is a cross-sectional view through the drive apparatus of FIG. 2;

FIG. 4 is a plan view of the drive assembly mounted in a sheet metal chassis;

FIG. 5 is an end view of the shaft and mounting arrangement;

FIG. 6 is an end view of the mounting arrangement for the clutch actuating bearing; FIG. 7 is a plan view of one bearing retaining member.

FIG. 8 is a side view of the belt tensioning device associated with the reversible belt drive apparatus; FIG. 9 is an inverted perspective view of the belt tensioning device associated with the cutter drive;

TITUTE SHEET

FIG. 10 is a top perspective view corresponding to FIG.

9;

FIGS. 11 and 12 illustrate the grass catcher assembly;

FIG. 13 is an exploded view of the drive axle assembly; FIG. 14 is a longitudinal cross-sectional view illustrating the operative arrangement of the differential, axle and drive wheel assembly;

FIG. 15 is a transverse cross-sectional view;

FIG. 16 is a longitudinal cross-sectional view illustrating yet another form of differential, axle and drive wheel assembly according to this invention;

FIG. 17 is a perspective view of the spur gear arrangement of the differential illustrated in FIG. 16, and FIG. 18 is an end view of the spur gear arrangement of the differential illustrated in FIG. 16.

A typical ride-on mower 10 as illustrated in Figs. 1 and 2 includes steerable front wheels 11, driven rear wheels 12, drivers foot pedals 13 at each side of the mower and a cutter housing 14 height adjustably supported beneath the mower's chassis 15. Drive apparatus for transmitting power from the motor 16 to the cutter housing 14 and to the rear wheels 12 includes a cutter drive belt 17 connecting the cutter housing shaft 18 with the motor 16 through idler pulleys 28 and a secondary drive belt 19 connecting the motor with the idler pulley 20 mounted beneath the seat 21.

The rear wheels 12 are supported on a rear axle assembly 22 driven through a chain 23 from a drive shaft 24. The latter supports a reversible belt drive assembly 25 having pulley wheels 26 contra-rotated by the opposite runs of the secondary drive belt 19. The drive pulleys 26 are suitably offset to one side of the tractor frame 15 beneath the operator's seat 21 whereby space is provided beneath the seat 21 and beside pulley wheels 33, 34 for a storage battery for the motor 16.

As illustrated in Figs. 3 and 4, the reversible belt drive assembly 25 includes a driven shaft 31 having a central portion 32 of square cross-section. A forward driven pulley 33 and a reverse driven pulley 34 are mounted to the driven

SUBSTITUTE SHEET

shaft 31 at opposite ends of the central portion 32 on bal bearings 35. Respective clutch plates 36 and 42 ar selectively engageable with the pulleys 33 and 34 t selectively rotate the shaft 31 either forwardly or i reverse.

The clutch plate 36 which engages with the revers pulley 34 includes a drive flange 37 and a boss 40 which ha a square cross-section bore 41 formed therethrough to engag slidably and non-rotatably with the central portion 32. Th forward clutch plate 42 includes a forward clutch flange 43 supported by a boss 44. The latter incorporates a bearin land 45 on its inner end on which the inner race 46 of a clutch actuator bearing 47 is mounted. The outer end 50 of the bearing land 45 is peened and rolled over to secure the inner race 46. The bore 51 of the boss 44 is recessed centrally as illustrated at 52. The clutch actuator bearing 47 is supported on the forward clutch plate 42 as that the member has an elongated hub whereby contact pressure between the square bore of the hub and the square portion of the drive shaft 14 is reduced. The adjacent plate 36 floats freely along the square drive shaft and abuts the throw-out bearing 47 whereby it may be forced into engagement with the drive plate 37. The clutch flanges 37 and 43 are faced with clutch facings 53, and are urged away from the driven pulleys 33 and 34 by centralising springs 54.

As can be seen in Figs. 4 and 6, the actuating member 60 for urging the clutch plates 36, 42 into and out of engagement with a selected pulley wheel 33, 34 is in the form of an arm which extends diametrically across the drive assembly 25 and includes a central bearing retaining portion 61 in which the throw-out bearing -47 is retained. The opposite ends of the actuating member 60 extend outwardly beyond the pulley wheels 33, 34 and connect via quick release pin connections 63 to respective links 64 of a parallel linkage assembly 59 which is actuated by rocking one of the heel/toe foot pedals 13.

Both links 64 pass to respective bell crank members 65 which are interconnected to a common push/pull link 66, which may be length adjustable if desired. The push/pull link 66

SUBSTITUTE SHEET

is actuated by a pivot link 67 which pivots about a fixed mounting pin 70 and is thus slotted at 71 to enable the pivot link 67 to move longitudinally with pivotal movement of the bell cranks 65. A linkage 68 is connected between the pivot link 67 and one rocking pedal 13 whereby it is adapted to be pulled by applying toe pressure to the foot pedal for forward motion. Such action pushes the push/pull link 66 causing translation of motion through the bell cranks 65 with resultant pushing of the actuating member 60 towards the forward drive pulley 33 and accompanying engagement of the clutch 36 therewith.

This arrangement is chosen such that the relatively long linkage assembly 68 which extends between the pivot link 67 and the foot pedal 13 is maintained in tension when the drive mechanism is actuated in its forward direction. The linkage assembly 68 is of course placed in compression in reverse mode. However in reverse mode, less drive torque is required to be transmitted from the drive assembly 25 and thus less force needs to be transmitted through the actuating member 60.

It will be seen from the above that the actuating linkage assembly 59 operates the actuating member 60 for reciprocal axial motion along the driven shaft 31 and thus it provides an effective means of transferring movement of the foot pedal 13 to actuation of the drive assembly 25. Furthermore the drive assembly can be easily removed from the chassis 15 by releasing the quick connection pins 63 and the mounting bolts 73 which secure the flangette bearings 35 to the chassis 15 and then by lifting the drive assembly 25 complete with the actuating member from the chassis.

For the purposes of replacing drive belts, sufficient clearance is left between the drive wheels 33 and 34 and the adjacent opening edge 78 such that a V belt may be inserted therebetween and placed into the grooves of the drive wheels 33 and 34. The belt may pass over the actuating member 60 subsequent to the rear end of the latter being disconnected by the quick connect pin 63.

The actuating member 60 retains the bearing 47 between part circular portions 55 of identical overlapping arms 56

SUBSTITUTE SHEET

which are bolted together by through bolts as illustrated. The arms 56 are so formed that the shank portions are co- planar. The bearing 47 is retained against axial movement relative to the arms 56 by forked retainer plates 57 fitted between the overlapped portions of the arms 56. Each plate 57 is forked at its inner end so as to neatly accommodate the periphery of the bearing 47 between the its fingers 58.

The linkage assembly 68 incorporates spring 72 disposed about the push/pull rod 73 an between an adjustable nut 76 on the rod 73 and an abutment collar 74 formed on an extension bar 75. A further collar 77 is formed on the extension bar 75 to slidably locate the trailing end of the rod 73. Thus in use, the spring 72 limits the force applied to the actuating member for reverse operation with operation of the foot pedal 13.

The drive assembly 25 is suitably located within a square cutout 80 in a folded steel plate chassis 15. For this purpose the cutout is terminated by mounting flanges 81 folded from the opposed sides of the cutout 80. The flanges 81 are each provided with a doubler 82 which is suitably bolted thereto along the full length of the flange. Each doubler 82 is suitably in the form of a carrier plate which extends below the chassis and provides mountings or a mounting for the rear axle assembly 90. As shown in Figs. 4 and 5, the flanges 81 extend transverse to the shaft 31 from opposite sides of a relief cutout 83 formed in the sheet metal chassis adjacent the opening 80 to enable the bearings 35 to extend down beyond the upper face of the chassis. This arrangement permits the centreline of the drive shaft 31 to be disposed close to the chassis surface 84 such that axial loads applied through the drive shaft by the actuating member 60 do not result in significant flexing of the flanges 81. Thus operation of the drive assembly 25 by the actuating member 60 is enhanced. Furthermore it will be seen that the sprocket 84 is located close to the forward drive pulley wheel 36. Accordingly the drive load path in the forward mode is minimised thus further minimising flexure within the shaft itself and assisting positive actuation of the drive. The

above described arrangement also provides an advantage in that the sheet metal from which the chassis is formed may be minimised, maintaining a low chassis weight.

Belt tension is maintained in the secondary drive belt by adjustment means 100 which supports the idler pulley 20. The adjustment means 100 is illustrated in Fig. 8.

The adjustment means 100 is adapted for supporting the idler pulley 20 for movement along a slotted frame bracket 102. The pulley 20 is mounted on a spindle assembly 103 rigidly attached to a slide bar 104 which is mounted within guide apertures 105 formed in end plates 106 and 107 of the frame bracket 102. The bar 104 is supported in use such that it extends parallel to the runs 108 of the drive belt 109 which passes about the pulley 20. The spindle 103 passes through a slide bearing 120 which engages about the edges of the slot 121 and stabilizes the pulley 20.

A spring pawl 122 attached at one end to the bracket 102 extends angularly to the bar 104 whereby its outer end 123 is biassed through is own resilience into engagement with the bar 104 and with a plurality of notches 124 formed along a portion of the bar 104. The pawl 122 permits the bar 104 to move freely in the direction away from the belt runs 108, the ratchet direction, but prevents opposite movement towards the belt runs 108. A tension spring 125 is attached at one end to the end plate 107 and extends alongside the bar 104 and its other end connects to the bracket 126 fixed to the end 127 of the slide bar 104. The tension spring 125 forces the bar 104 in the ratchet direction. A spring release trigger 128 is fixed to the pawl 122 and extends away therefrom to protrude beyond the frame bracket 102 whereby the .outer end 129 of the trigger 128 may be manipulated to deflect the pawl away from the slide bar 104. The deflected attitude of the spring pawl is illustrated in dotted outline at 130. The trigger is used when the spring 125 has been released from the bar 104 to enable the bar 104 to move freely in through the end plates 106 and 107 such as for moving the pulley to the rear 131 of the slot 121 to enable the belt 109 to be either removed or replaced, as shown in dotted outline at 132.

^; SUBSTITUTE SHEET

In use, as illustrated, a V-belt 19 which is to be tensioned is passed around the pulley 20. The tension spring 125 draws the slide bar 104 through the guide apertures 105 to tension the belt 19 while the outer end 123 of the spring pawl 122 rides up and over the notches 124 until the V-belt 19 has been drawn into a state of tension controlled by the force in the tension spring 125. The bar 104 is prevented from oscillating or reducing belt tension by engagement between the pawl end 123 and one of the notches 124. The spring 125 will automatically advance the bar 104 in the ratchet direction as the belt wears or stretches and sufficient slack appears in the belt 109 such that the cumulative tension in the belt runs is less than the tension of the spring 125. The notches 124 are arranged close together such that such movement is accompanied by engagement of the pawl with the next notch.

When it is necessary to move the slide 102 back to a low belt-tension position, such as for changing the belt, the spring 125 is released and the trigger 128 is manipulated to release from the bar 104 allowing it to be slid through the guide apertures 105 and so position the pulley 20 that the belt may be released therefrom.

Belt tension is maintained in the cutter drive belt 147 by adjustment means 135 which supports the idler pulley 28 at the front 136 of the chassis about which the return run of the cutter belt 17 passes. The adjustment means 135 is illustrated in Fig. 9.

The drive belt 17 passes forwardly from the engine mounted driving pulley 29 attached to a vertical-shaft motor 16 for return about idler pulleys 28 to the driven pulley 18. This arrangement provides a relatively long belt run to the driven pulley 18 which is advantageous for the purposes of raising and lowering the driven pulley 18 with the cutter housing. The belt 17 passes from the smaller driving pulley 29 forwardly beneath the mower chassis 15, rotating a quarter- turn to engage with the idler pulleys 28 before returning to the larger driven pulley 18. The idler pulleys 28 are supported for rotation on pulley carriers 147 and 148 which

^{^}

m

C ³

H C

H m

rrt m H

control of the rod 166, including locking it in a retracted position to prevent drive being transferred through the drive belt 17. The push rod assembly 166 is shown disconnected in the drawings, however it will be apparent that the spring 170 urges the rod 171 substantially parallel to the shaft 154 so as to maintain appropriate tension in the belt 17. The bearing end 172 of the rod may be engaged in either aperture 167 to achieve the desired tension. Other forms of adjustment may also be provided as desired such as length adjustment of the rod 171.

As shown in Fig. 1 a grass catcher 30 may be fitted to the mower 10. Details of the grass catcher are illustrated in Figs. 11 and 12.

In Fig. 11, the dotted outline 180 represents the grass outlet of the cutter housing 14 and the dotted outline 181 represents the grass inlet of the catcher 30. The inlet 181 is maintained in alignment with the outlet 13 by engagement between an upstanding pin 182 fixed to the cutter housing and engaging through an aperture 184 of a flange 185 extending along the upper edge of the inlet 181. The flange 185 rests upon the cutter housing 14 to support the leading end of the catcher 11 which is able to move up and down with height adjustment of the cutter housing 14. In this manner the leading end of the catcher 30 may be readily secured in position by lowering it to engage the aperture 184 about the pin 182.

The upper extremity of the grass inlet 181 of the grass catcher 30 is disposed below the top face 183 of the catcher housing 186 and the space between the top face 183 and the mounting flange 185 increases rearwardly from the leading edge of the grass outlet 180. This arrangement forms an air space 187 above the inlet 181 in which cut grass does not accumulate and which alleviates the build up of cut grass at the neck portion 190 of the grass catcher 10. Thus grass flows efficiently rearwardly from the grass catcher inlet 181 into the main body of the catcher 30. To facilitate grass flow, the rear side wall is formed of mesh as is the breathing panel 191 in the back wall/door 192.

The rear of the catcher 30 is supported by a bar

193 extends transversely from the mower 10 which extends beneath the housing and is located in slotted brackets 194 fitted to the underside of the housing 186 whereby it may pivot about and slide along the bar 193. The rear closure door 192 is mounted along its inside edge on hinges 195 and a spring 196 selectively holds the door 192 in the closed or open position. An upstanding strut 197 forms a door mounting for the spring and provides a handle which is accessible to the driver of the mower whereby the door 192 can be readily moved to the open position by a seated operator as illustrated in Fig. 12.

In use, the catcher 30 is fitted to a mower 30 by firstly connecting the cross bar 193 thereto to provide the rear pivotal support and subsequently supporting the front of the catcher 30 on the cutter housing 14 with pin 182 passing through the aperture 184. The catcher 30 may be manually moved in a longitudinal direction to permit operative alignment of the pin 182 with the aperture 184. After mowing, when the catcher is full, the user simply pivots the door 192 to its over-centre open position at which it is held by the spring 196, grasps the handle 198 and tilts the catcher 30 about the bar 193 to tip the contents thereof through the open rear end 198.

As shown in FIG. 13 the axle assembly 210 includes a transverse axle 211 provided with keyed land portions 212 and 213 at each end thereof. The axle 211 is also provided with a fixed sun gear 214 adjacent keyed land portion 213. The sun gear has a collar 215 which is adapted to locate within the bushed hub 216 of a drive sprocket 217 provided with bolt apertures 218 through which bolts may pass to connect an open ended tubular housing 219 to an opposed end plate 220. A shim 221 is adapted to be inserted between the sprocket and the back face of the gear 214 so as to enable the mesh between the gear 214 and opposed planetary gears 222 supported in the housing 219 to be adjusted. The planetary gears 222 are mounted on respective stub axles 223 fixed to the housing 219.

The axle 211 is further provided with a bearing surface 225 on which a tubular stub axle 226 may rotate. The tubular

SUBSTITUTE SHEET

stub axle 226 is formed integrally with a further sun gea 227 adapted to mesh with the planetary gears 222. A furthe shim 228 is provided for placement between the back face o the gear 227 and the end plate 220. The tubular stub axle 226 is also provided with an outer key 230 so that it may be locked to a wheel hub 231. The latter is provided with studs 229 which pass through the mounting apertures 232 in the wheel 233. At the other end of the axle 211 a further carrier 240 mounts on the keyed land portion 212 and connects to the wheel 241 through studs 242. The wheel 233 is adapted to be locked to the studs 229 through wheel nuts 245 which have extensions 246 formed thereon. The extensions 246 are adapted to engage within respective radial slots 247 in a locking plate 250 having a hub 251 which is keyed to the keyed land portion 213.

The arrangement is such that drive is transmitted to the housing 219 and to either one or both of the sun gears 214 or 227 by the planetary gears 22. The latter assembly will provide a differential action between the wheels 233 and 241 in known manner. However if during use further drive is required in situations where one wheel may slip and cause drive to be lost, the differential assembly 300 may be locked by moving the locking plate 250 along the keyed land portion 213 until the wheel stud extensions 246 engage within the slots 247. In this configuration neither wheel may spin independent of the other. Both will be driven through the differential assembly 300 for simultaneous rotation.

From the above it will be seen that the differential can be formed inexpensively through using very simple components such as cropped tubing to form the housing and a simple dog clutch to provide the differential lock mechanism. Furthermore the differential may be associated directly with a sprocket or the like with simple mountings as per conventional solid axle assemblies. Figs. 14 and 15 illustrate sections of the differential assembly 300 in more detail. As illustrated, the differential housing 219 is machined from mild steel tubing and formed with opposing apertures 252 to accept the stepped threaded ends 253 of the pinion stub axles 254. The pinion

SUBSTITUTE SHEET

18 stub axles 254 also pass through hardened and groun rectangular supporting blocks 255 which self align over th pertures and engage securely with the inner wall of th hous ⁱ ng 219 when the securing nuts on the threaded ends 25 are tightened.

The corners of the hardened square blocks 255 bite int the relatively soft inner wall of the housing 219 and th square ends of the blocks 255 abut either end plate so tha ⁱ n use accurate location of the blocks and the planetar gears 222 supported thereby is provided. Furthermore, th through bolting apertures 218 are arranged at each side o the blocks 255 such that effective bolting together of th hous ⁱ ng components may be achieved without distortion of th components. The axle 211 is stepped at 256 to provide a locatin shoulder for the side gear 214 which is secured thereto by . ² " ^{" he keyed hub 251} of the locking mechanism i sl dable along the end of the axle 211 and along th assoc ⁱ ated key 260 between disengaged and engaged positions, ⁱ llustrated in full and dotted outlines respectively in Fig 14, and at which a sprung ball 261 engages with a respective one of the indents 262.

As shown in FIGS 16, 17 and 18 the differential assembly 265 ⁱ ncludes a chain driven sprocket 266, an end plate 267 and a tubular housing 268 which enclose the remainder of the ^di fferential assembly ^, A first set of planetary gears 270 each hav ⁱ ng a spindle portion 271 is rotatably- mounted on the sprocket 266 and are adapted to mesh with a second set of planetary gears 272 each having a spindle portion 273 also rotatably mounted on the sprocket 266 whereby drive may be transferred by the enmeshed contra-rotating spur gears 270, 272 engag ⁱ ng with respective sun gears 280, 281. The first set of planetary gears 270 has the spindle portions 271 ^di stally disposed from the sprocket 266 whereas the second set of planetary gears 272 has the spindle portions prox ⁱ ally disposed to the sprocket 266.

The first set of planetary gears 270 mesh in orbiting relat ⁱ onship with a first sun gear 280 which is fixedly mounted on a main axle 282. in like manner, the second set

of planetary gears 272 mesh in orbiting relationship with a second sun gear 281 which is fixedly mounted on a tubular stub axle 283. The main axle 282 passes through the tubular stub axle 283 and has a dog-clutch 284 mounted on a dog- clutch land 286 on the end of the axle 282 adjacent the differential side of the sprocket 266. The tubular stub axle 283 has a wheel mounting land 287 for mounting a wheel

288 thereon. The wheel includes a dog clutch engaging pin

289 for engaging the dog clutch 284. Another wheel (not shown) is mounted on the other end of the main axle 282.

The differential housing is sealed by oil seals 290, one of which seals the housing adjacent where the main axle 282 passes through the sprocket 266 and another which seals the housing adjacent where the stub axle 283 passes through the end plate 267.

If during use, drive is required in situations where one wheel may slip and cause drive to be lost, the differential assembly 265 may be locked by moving the dog clutch 284 axially along the land portion 286 until the dog clutch 284 engages with the engaging pin 291 on the wheel 288. In this configuration neither wheel may spin independently. Both will be driven through the differential assembly 265 for simultaneous rotation.

As shown in FIG. 19 the differential lockout mechanism may be substituted by a clutch assembly 300 whereby the degree of relative rotation between the inner axle 301 and the outer tubular axle 302 through the differential 303 is selectively variable. In this embodiment the differential lockout mechanism 300 is in the form of a clutch assembly 304 having a first clutch plate 305 secured to the wheel 306 by the wheel studs 307 and a second clutch plate 308 keyed to the shaft 301 by key 309 for free sliding movement therealong. Friction facings 310 are provided as illustrated. The end of the shaft 301 is couterbored and threaded at 311 to receive a finger operable adjusting nut 312 through which axial pressure may be applied through the collar 313 to the clutch plate 308 so as to force the clutch plate 308 into engagement with the clutch plate 305. A spring 314 is interposed between the hub 315 of the clutch

HEET

.20 plate 308 and the collar 313. The finger nut 312 may t ⁱ ghtened to effectively lock the shaft 301 to the shaft 3 or loosened to provide full differential action. Of cour the f ⁱ nger nut may be adjusted intermediately above positio to prov ⁱ de a limited slip facility with selected slip bei available to the user.

SUBSTITUTE SHEET