GB1603912A

GB1603912A - Vehicles

Info

Publication number: GB1603912A
Application number: GB2163478A
Authority: GB
Original assignee: C Van der Lely NV
Current assignee: C Van der Lely NV
Priority date: 1977-06-07
Filing date: 1978-05-23
Publication date: 1981-12-02
Also published as: FR2393717A1; DE2824702A1; NL7706236A

Description

PATENT SPECIFICATION ( 11

( 21) Application No 21634/78 ( 22) Filed 23 May 1978 ( 31) Convention Application No.

7706236 ( 32) Filed 7 June 1977 in ( 33) Netherlands (NL) ( 44) Complete Specification published 2 Dec 1981 ( 51) INT CL B 60 K 1704// B 60 B 23/12 B 60 K 17/28 ( 52) Index at acceptance B 7 H C 16 C C 1 A 2 C 8 X C 9 K 5 EIB E 2 E M 2 M 5 A 2 Pl P 4 P 7 A 2 V 2 B Al P 2 B 2 C B 7 C 5 G 3 ( 54)IMPROVEMENTS IN OR RELATING TO VEHICLES ( 71) We, C VAN DER LELY N V, of 10, Weverskade, Maasland, The Nteherlands, a Dutch Limited Liability Company, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:The invention relates to vehicles, and particularly, although not exclusively, to tractors.

According to the present invention there is provided a powered vehicle supported by ground wheels with an engine driving at least two of the ground wheels through a stepless change-speed mechanism having input and output shafts which extend generally upwardly.

For a better understanding of the present invention and to show how it may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings, in which:

Figure 1 is a side elevational view of the tractor; Figure 2 is a plan view of the tractor shown in Figure 1; Figures 3 to 6 are horizontal elevations, partly in cross-section, of one of the wheels of the tractor shown in Figures 1 and 2 taken in a direction perpendicular to the wheel axle, showing different wheel dispositions relative to the wheel axle.

Figure 7 is a horizontal side elevation of a detail of the tractor of Figure 1, some parts being omitted; and Figure 8 is an elevational view in the direction of the arrow VIII in Figure 7.

The tractor shown in Figures 1 and 2 comprises a frame having, as shown in the side elevation of Figure 1, a rear frame part extending horizontally and connected to a front frame part which is inclined upwardly in the forward direction The frame 1 is supported by a pair of steerable front wheels 2 and two pairs of rear wheels 3 and 4 The wheels of each pair 2, 3 and 4 are arranged one on each side of the tractor.

Viewed in the direction of forward travel A, the rear wheels 3 and 4 on each side of the tractor are in line with one another.

The diameters of the rear wheels 3 and 4 are substantially equal to one another and amount to about 1 metre The rear wheels 55 3 and 4 are rotatable about respective wheel axles 5 and 6, which may be fixed to the frame 1, the distance between the wheel axles 5 and 6 being slightly greater than the wheel diameter The front wheels 2 60 are rotatably mounted on stub axles 7, each of which is located at a distance in front of the respective axle 5 which is more than twice the diameter of each rear wheel The diameter of each front wheel 65 2 is smaller than that of the rear wheels 3 and 4.

The front wheels 2 are steerable from a driver's seat 8 which is disposed above the tops of the rear wheels 3 and 4 and, in the 70 position shown in Figure 1, between vertical planes containing the wheel axles 5 and 6 The driver's seat 8 is mounted on a console 9 to which is fastened, in addition, a column 10 provided with a steering 75 wheel 11 and some, if not all, other steering and controls members of the tractor.

The assembly of the seat 8, the console 9, the column 10, the steering wheel 11 and the other steering and control members 80 is nivotable as a unit about a substantially vertical pivotal axis 12 located in the vertical, longitudinal plane of symmetry of the tractor and fixable in two positions differing by 1800 so that the seat 8 may face either 85 forwardly or rearwardly with respect to the direction A The driver's seat is surrounded by a cab 13, having inclined front and rear screens 13 A and 13 B which diverge upwardly as can be seen in the side ele 90 vation of Figure 1 Measured in a horizontal direction perpendicular to the direction A, the width of the cab 13 at a position approximately midway along its length is greater than the width of the cab at the 95 front and rear sides, and the rear screen is significantly narrower than the front screen.

The tractor has a driving engine 14 located as viewed on plan, between the 100 1) 1 603 912 1603912 wheel axles 5 and 7 At its rear, the engine 14 is provided with a clutch 15 which actuable from the driver's seat 8 The clutch has an output shaft 16 which is connected by a universal joint 17 with a driving shaft 18 which is connected by a further universal joint 19 with an input shaft of a gear box 21, the pinions of which are axially fixed relatively to one another (see Figures 1 and 7) The input shaft 20 is supported in bearings 22 and 23 and is provided with a pinion 24 which is disposed between these bearings and which meshes with a pinion 25 located beneath it which has a pitch exceeding that of the pinion 24 The pinion 25 is fastened to a shaft 26, the two ends of which protrude from the housing of the gearbox 21.

The shafts 20 and 26 are parallel to one another and extend substantially horizontally and parallel to the direction A The shaft 26 is supported in the gear box 21 by bearings 27 and 28 located one on each side of the pinion 25.

The end of the shaft 20 remote from the universal joint 19 is provided with a bevel pinion 29 which meshes with a bevel pinion 30, the pitch circle diameter of which is approximately double that of the pinion 29 The pinion 30 is fastened to the lower end of an upwardly extending shaft 31 The shaft 31 is an output shaft of the gear box 21 and constitutes the input shaft of a stepless change-speed mechanism 32.

In this embodiment the shaft 31 is generally vertical and is located in the vertical, longitudinal plane of symmetry of the tractor.

The gear box 21 is disposed, as viewed on plan, near the wheel axle 5 and between the wheel axles 5 and 6, whilst its lower side is located approximately in the plane containing the shafts 5 and 6 The general arrangement is such that the pivotal axis 12 intersects the shafts 20 and 26 in the regions of the bearings 23 and 28 The shaft 31 is supported at its lower end in a housing 34 of the change-speed mechanism 32 by a bearing 33 The shaft 31, as well as being the input shaft of the change-speed mechanism 32, is also an input shaft of a control mechanism 35 for the adjustment of adjustable pulleys 36 and 37 each comprising a pair of conical discs The rotary axis of the adjustable pulley 36 coincides with the centre lines of the shaft 31 Between the discs of the pulley 36 lies a chain or belt 38, which also extends between the axially adjustable discs of the pulley 37.

The pulley 37 is rotatable about an unwardly extending output shaft 39, which is parg Ilel to the shaft 31 The output shaft 39, which is telescopic to allow turning of the assembly i the rear wheels 3 and 4 about a pivotal axis located between the wheel axles 5 and 6, extends substantially vertically downwardly from the housing' 34 and constitutes and input shaft of differential 40 (Figure 8) by means of which the wheel axles 6 of the rear wheels 4 can be driven with considerable speed reduction 70 The diameter of each disc of the pulley 36 and 37 is preferably at least about 60 cms The transmission ratio in the gear box 21 is such that an ouput speed of the Diesel engine 14 of about 2000 rev/min 75 results in an input speed of the changespeed mechanism 32 (i e the rotational speed of the shaft 31) of about 1000 rev/ min, whereas the output speed of the change-speed mechanism 32 (i e speed of 80 the shaft 39) may vary by adjustment of the pulley discs from about 270 to about 4000 rev/min Thus, with such a construction, a ratio of speed variation of at least 1 to 10 (in this embodiment the ratio is 85 1 to 15) can be obtained.

The change-speed mechanism 32 extends behind the rearmost wheel axle 6 and, viewed on plan, it is located mostly, if not wholly, behind the driver's seat 8 The 90 fairly large size of the pulleys 36 and 37 is possible because both of these pulleys rotate in a horizontal plane so that substantially the whole width of the tractor frame is available to accommodate them 95 The housing 34 has a removable rear wall 41 so that the internal mechanism of the change-speed mechanism 32 is accessible from the rear of the tractor This rear wall 41 of the housing 34 is disposed at a dis 100 tance behind the cab 13.

The front end of the shaft 26, with respect to the direction A, is connected by a universal joint 42 to a drive shaft 43, which extends forwardly from the gear box 105 21 with its centreline located approximately in the vertical, longitudinal plane of symmetry of the tractor The shaft 43 is connected by a universal joint 44 to an input shaft 45 of a gear box 46, which is fastened 110 to the front part of the frame 1 approximaely midway between the wheel axles and 7, as shown in the side elevation of Figure 1, and is located in the longitudinal plane of symmetry of the trac 115 tor The gear box 46 is provided with an output shaft 47, the centre line of which coincides with that of the input shaft 45 and which is therefore also located in the vertical, longitudinal plane of symmetry of 120 the tractor, whilst it furthermore has output shafts 48 and 49, which are horizontal and perpendicular to the vertical, longitudinal plane of symmetry of the tractor The shafts 45 and 47 constitute an uninterrup 125 ted shaft, whereas the output shafts 48 and 49 are driven by the input shaft 45 (Figures 1 and 2) via a bevel pinion transmission The output shafts 48 and 49 project laterally from the sides of the frame 130 _j ob 1 603 912 1 and constitute power take-off shafts 50 and 51 (Figure 2) Near the power takeoff shafts 50 and 51 are provided threepcint Liting devices 52 and 53, one on each side of the tractor frame 1, these devices each being disposed substantially symmetrically about a vertical plane containing the centreline of the respective power take-off shaft 50 and 51 The lifting devices 52 and 53 each comprise lower lifting arms 54 and an upper lifting arm 56.

The lower lifting arms 54 are secured to the lower side of the frame 1 for pivotal movement about horizontal pivotal shafts 55 which extend substantially in the direction A The upper lifting arm 56 of each threepoint lifting device 52 and 53 is pivotably mounted, at a distance above the frame 1, on a horizontal pivotal shaft 57 which extends in the direction A The lifting arms of each of the lifting devices 52 and 53 extend outwardly from the frame approximately as far as a plane coinciding with the outer boundary plane of the respective rear wheels 3 and 4 The pivotal shafts 55 of the lower arms of each of the lifting devices 52 or 53 are relatively coupled and pivotable by means of a separate hydraulic cylinder associated with the respective lifting device, this cylinder being journalled, in a manner not shown, on the lower side of the frame 1 and extending transversely of the direction A so that each lifting device can be individually operated.

The output shaft 47 of the gear box 46 is connected to a driving shaft 58, which is journalled at the front of the frame 1 and protrudes from the front of said frame to constitute another power take-off shaft 59 At the front of the frame 1 is disposed a three-point lift 60 which is arranged substantially symetrically about a vertical plane containing the centre line of the powertake-off shaft 59.

The rear end of the shaft 26 of the gear box 21 is connected by a universal joint 61 to a driving shaft 62, which is connected by a universal joint 63 to the front end of a shaft 64, the centre line of which lies in the vertical, longitudinal plane of symmetry of the tractor (Figure 7) The shaft 64 is journalled in the housing of the differential 40, where also the rear wheel axles 6 are connected The shaft 64 projects into the housing of the differential 40 beneath the gear wheel mechanism thereof.

As viewed in the direction A the shaft 64 projects from the rear side of the housing and constitutes a power take-off shaft 65.

A three-point lift 66 is fastened to the rear side of the tractor and is arranged symmetrically about a vertical plane containing the centre line of the power take-off shaft 65 The three-point lift 66 has an upper lifting arm 67 which is pivotally mounted on a support 68, which is provided on the upper side of the housing of the differential 40 and is inclined upwardly and rearwardly The three point lift 66 also has lower lifting arms 68 A fastened 70 to supports 69, which are welded to the lower sides of hollow wheel carriers 70 which surround the wheel axles 6 Hydraulic systems are provided (not shown) for actuating the lifting devices 52, 53, 75 and 66 and can be controlled from the driver seat 8.

The ground wheels 2, 3 and 4 are provided with tyres The tyres of the rear wheels 3 and 4 on each side of the tractor 80 are surrounded by an endless track 71, which may be provided along its length with one or more joints (not shown) for mounting purposes The endless track 71 on each side of the tractor comprises a 85 circulating belt 72 (Figure 1) which is provided with outwardly extending ribs 73 extending over the whole width of the belt 72 (which is preferably about 30 cms).

On the inner side of the belt 72 there are 90 studs 74 which are spaced apart from one another transversely of the direction A by a distance such that the tyres of the wheels 3 and 4 fit in between them with the rows of studs 74 on either side of the tyres 95 firmly engaging the flanks of the tyres The belt 72 and the ribs 73 and the rows of studs 74 are preferably integral with one another and made from a synthetic resin or a rubber-like material, which may be 100 reinforced by liners.

The wheel axles 5 and 6 may be rigidly fastened with respect to the tractor frame 1, but as an alternative these wheel axles, together with the two pairs of wheels 3 105 and 4, may be journalled in beams 3 A (Figure 1), these beams being freely pivotable about a common horizontal pivotal shaft 3 B which extends transversely of the direction A and is journalled in the frame 110 1 in order to ensure optimum matching of the ground The pivotal shaft 3 B is offset, as viewed from the side, from the midpoint between the wheel axles 5 and 6, and is located approximately 30 % of 115 the distance between the axles 5 and 6 from the rear wheel axle 6 At the front of the beams 3 A are provided guides 3 C (Figure 2) for the movements of the pairs of wheels about the pivotal shaft 3 B 120 The distance between the two front wheels 2 and the distance between the two rear wheels 3 and between the two rear wheels 4, measured transversely of the direction A, can be adjusted Figures 3 to 125 6 illustrate various settings of a front wheel 2 Different settings of the rear wheels 3 and 4 can be obtained in the same manner.

The wheel axle concerned (in this case the wheel axle 7) is provided with a hub 130 1 603912 75, to which an arcuate, hollow wheel disc 77 is secured by bolts 76 As viewed in a direction parallel to the centre line of the axle 7, the wheel disc 77 has a square shape (Figure 1) Holes are provided at the four corners of the wheel disc 77 for receiving bolts 78, which can be screwed into tapped holes provided in axial sleeves 80 fastened to the rim 79 The screwthread extends along the whole length of the hole in each sleeve 80 so that the bolts 78 can be screwed into the holes from either end.

The four sleeves 80 of each wheel are secured to the rim 79 so that one end face of each sleeve 80 coincides with the plane of symmetry 81 of the tyre and of the rim 79 Figure 3 shows that each sleeve 80 is located completely inboard of the plane of symmetry 81 In this Figure the plane of symmetry 81 coincides with a plane 82 to which the wheel axle 7 is perpendicular and which is in a fixed axial position relative to the axle 7.

With the arrangement as it is shown in Figure 3, the track width, i e the distance between the wheels 2, is at its smallest To adjust the track width, the bolts 78 are removed and the assembly of the rim 79 and the tyre is removed outwardly This removal of the rim and the tyre is made possible by rotating them slightly about the wheel axle 7 after the bolts 78 are removed so that the corners of the wheel disc 77 can pass between the sleeves 80 Then the assembly of the rim and the tyre is bolted to the wheel disc 77 with the sleeves 80 on the opposite side of the disc 77 to that which they were on in the position of Figure 3 Figure 4 shows that, in the resulting configuration, the plane of symmetry 81 is thus displaced outwardly from the stationary plane 82 by a distance equal to the length of the sleeves 80 plus the thickness of the wheel disc 77.

To increase the track width even further, the bolts 76 are removed and the wheel disc 77 is turned around and re-fastened by the bolts 76 to the hub 75 so that, owing to the dished shaped of the wheel disc 77, the regions of the disc 77 to which the sleeves 80 are bolted are further out from the plane 82 than they were before This disposition of the wheel disc 77 is illustrated in Figure 5 in which the assembly of the rim 79 and the tyre is fastened to the wheel disc 77 by the bolts 78 in the same way as in Figure 3, i e with the sleeve 80 inboard of the disc 77 It will be appreciated that the distance between the planes 81 and 82 is larger in the configuration of Figure 5 than in that of Figure 4 Figure 6 shows a disposition of the wheel disc 77 with respect to the hub 75 which is the same as that in Figure 5, but the assembly of rim and tyre is fastened to the wheel disc 77 in the same way as shown in Figure 4 In the configuration shown in Figure 6, the distance between the planes 81 and 82 is again larger than the same distance in the configuration of Figure 5 The track width 70 in the arrangement of Figure 3 is about 180 cms It is thus possible to adjust the track width of two wheels on either side of the tractor to four different values, as desired.

This adjustability of the track width is use 75 ful for adapting the tractor wheels so that they match the distance between rows of plants.

It should be noted that the adjustments of the track width as described above may 80 be applied to all wheels 2, 3 and 4 so that the endless tracks 71 can be adjusted with respect to each other, since the endless tracks pass around the laterally adjustable wheels 3 and 4 85 During operation the rear wheels 4 are driven from the Diesel engine 14 through the clutch 15, the driving shaft 18, the bevel pinions 29 and 30 of the gear box 21, the shaft 31, the variable change-speed mecha 90 nism 32, the shaft 39 and the differential The front pair of rear wheels 3, which are freely rotatable about the wheel axles are driven fromt he rear pair of wheels 4 by means of the endless track 71 The 95 engine 14 has an exhaust system having two exhaust pipes 83 loacted symmetrically one on each side of the lower side of the cab 13 and projecting upwardly near the two rear corners of the cab 100 The power take-off shafts 50, 51, 59 and provided near the four lifting devices 52, 53, 50 and 66 respectively are driven through the driving shaft 18, the shaft 20, the pinions 24 and 25 and the driving shafts 105 43 and 62, the power take-off shaft 65 being directly linked to the driving shaft 62 The front power take-off shaft 59 is driven from the driving shaft 43 through the shaft 45, 47 passing through the gear box 46, and the 110 shaft 58, whereas the power take-off shafts and 51 are driven by means of the pinion mechanism in the gear box 46 from the input shaft 45.

In this way the tractor can be employed 115 universally so that the amount invested in the tractor can be very economically exploted since all sides of the tractor can be used for carrying and driving tools, whilst on weak soil the endless tracks mini 120 mise skidding or subsidence of the tractor even if it is carrying a heavy load.

To the front lifting device 60 and to the laterally projecting lifting devices 52, 53 may, for example, be attached rotary har 125 rows, whose working widths overlap or join one another Thus a considerably wider load distribution of the tractor is obtained compared with the case in which a machine having the same overall working width, is 130 1 603 912 only attached to the front lift 60, which machine would need to be appreciably heavier At the rear of the tractor, the lift 66 may have attached to it, for example, 3 a seed drill or a fertilizer distributor, the kind of operation of which corresponds with that of the aforesaid machinery, whilst the working width is the same The variable track width of the wheels improves the general utility of the tractor This adjustability of the track width does not affect the attachment of tools to all four lifts so that when the tractor is used for different kinds of row cultures a complete matching of tractor and tools is possible.

Claims

WHAT WE CLAIM IS:

1 A powered vehicle supported by ground wheels with an engine driving at least two of the ground wheels through a stepless change-speed mechanism having input and output shafts which extend generally upwardly.

2 A vehicle as claimed in claim 1, in which the change-speed mechanism has a ration of speed variation of at least 1:10.

3 A vehicle as claimed in claim 2, in which the ratio of speed variation of die change-speed mechanism is about 1:15.

4 A vehicle as claimed in claim 3, in which, in normal operation of the vehicle, the speed of the output shaft of the changespeed mechanism is adjustable in the range of 270 to 4000 rev/min.

A vehicle as claimed in any one of the preceding claims, in which the changespeed mechanism comprises two steplessly variable pulleys, which are coupled by means of a belt or a chain.

6 A vehicle as claimed in any one of the preceding claims, in which the changespeed mechanism comprises adjustable, conical, belt or chain pulleys extending generally horizontally.

7 A vehicl as claimed in claim 5 or 6, in which the outer diameter of the pulleys is about 60 cms.

8 A vehicle as claimed in any one of the preceding claims, in which, in normal operation of the vehicle, the speed of the input shaft of the change-speed mechanism is about 1000 rev/min.

9 A vehicle as claimed in any one of the preceding claims, in which, on each side of the vehicle, a pair of wheels is provided around which extends an endless track, these wheels and the endless track being laterally adjustable with respect to the rest of the vehicle.

A vehicle as claimed in claim 9, in which each endless track is made from a synthetic resin or a rubber-like material.

11 A vehicle as claimed in claim 9 or 10, in which each endless track is provided on its outer surface with ribs and on its inner surface with rows of studs, the rows being disposed one on each side of the wheels of the pair.

12 A vehicle as claimed in any one o 1 claims 9 to 11, in which each endless track, includinug the ribs and studs, integrally 70 comprises a single, integral, length of material.

13 A vehicle as claimed in any one of claims 9 to 12, in which the wheels of each pair have substantially equal diameters 75 14 A vehicle as claimed in any one of claims 9 to 13, in which the wheels of each pair are provided with tyres.

A vehicle as claimed in claim 14, when appendant to claim 11, in which the 80 studs contact the tyres.

16 A vehicle as claimed in any one of claims 9 to 15, in which the diameter of each of the wheels of each pair is about 1 metre 85 17 A vehicle as claimed in any one of claims 9 to 16, in which the wheels of each pair are disposed in line one behind the other with respect to the intended direction of forward travel on the vehicle, and he 90 rear one of the wheels of each pair is connected to be driven by the engine of the vehicle.

18 A vehicle as claimed in any one of claims 9 to 17, in which the front wheel of 95 each pair is mounted for rotation on a wheel axle.

19 A vehicle as claimed in claim 18, in which the front wheel of each pair is drivable solely by the endless track 100 A vehicle as claimed in any one of claims 9 to 19, in which the endess tracks are disposed in the region of the rear of the vehicle, with respect to the intended direction of forward travel of the vehicle, 105 and the vehicle is provided with further wheels in the region of the front of he vehicle.

21 A vehicle as claimed in claim 20, in which the front wheels are steerable 110 22 A vehicle as claimed in any one of the preceding claims, in which the distance between the endless tracks arranged on each side of the vehicle is adjustable.

23 A vehicle as claimed in any one of 115 claims 9 to 22, in which the width of each endless track is about 30 ems.

24 A vehicle as claimed in any one of claims 9 to 23, in which the minimum track width of the wheels is about 180 cms 120 A vehicle as claimed in any one of claims 9 to 24, in which each endless track and the wheels over which it extends are pivotable as a unit about a substantially horizontal pivotal axis extending transverst 125 ly of the intended direction of forward travel of the vehicle.

26 A vehicle as claimed in claim 25, in which the wheels and the endless track extending over them are freely pivotable 130 1 603912 about the pivotal axi.

27 A vehicle as claimed in claim 25 or 26, in which the pivotal axis is offset from a position halfway between the axes of rotation of the wheels.

28 A vehicle as claimed in claim 27, in which the distance of the pivotal axis from the rearmost wheel axis is smaller than the distance of the pivotal axis from the front wheel axis.

29 A vehicle as claimed in any one of claims 9 to 28, in which the change-speed mechanism extends rearwardly beyond the axis of rotation of the rearmost wheel of the pair.

A vehicle as claimed in claim 29, in which the change-speed mechanism is disposed at least partly above the level of a plan containing the axes of the driven wheels.

31 A vehicle as claimed in claim 29 or 30, in which the change-speed mechanism extends over the axis of the rearmost wheel of the pair.

32 A vehicle as claimed in any one of the preceding claims, in which a driver's seat is provided.

33 A vehicle as claimed in claim 32 when appendant to any one of claims 9 to 31 in which the driver's seat is located above the wheels of the pairs, as viewed from the side.

34 A vehicle as claimed in claim 32 or 33, in which the change-speed mechanism extends rearwardly beyond the driver's seat.

A vehicle as claimed in any one of claims 32 to 34 in which the driver's seat can be turned together with steering and control members of the vehicle and be fixed in two positions.

36 A vehicle as claimed in any one of claims 32 to 35, in which the driver's seat is surrounded by a cab having a front screen and a rear screen, the rear screen being significantly lower than the front screen.

37 A vehicle as claimed in claim 36, in which the front screen and the rear screen are inclined to the vertical and diverge upwardly.

38 A vehicle as claimed in claim 36 or 37, in which exhaust pipes extending from the vehicle engine pass near the corners of the cab.

39 A vehicle as claimed in any one f claims 36 to 38, in which the cab has a larger width at a position between its front and rear ends than it has at its front and rear ends.

40 A vehicle as claimed in any one of the preceding claims, in which the engine of the vehicle is drivingly connected to the change-speed mechanism by a pinion mechanism comprising bevel gear wheels, to which pinion mechanism at least one power take-off shaft is drivingly connected.

41 A vehicle as claimed in claim 40 m which the pinion mechanism comprises an output shaft directed longitudinally of the vehicle from which shaft four power take 70 off shafts are drivable with a speed solely determined by the engine speed.

42 A vehicle as claimed in any one of the preceding claims, in which the vehicle has power take-off shafts at the front, the 75 rear and one each side.

43 A vehicle as claimed in claim 42, in which near each power take-off shaft is provided coupling means for attaching implements 80 44 A vehicle as claimed in claim 43, in which the coupling means each comprise a three-point lifting device.

A vehicle as claimed in claim 44 when appendant to any one of claims 32 85 to 39, in which the lifting devices are connected to be actuated from the driver's seat.

46 A vehicle as claimed in any one of claims 43 to 45, in which the coupling 90 means and the power take-off shafts arranged on the sides of the vehicle are located, as viewed from the side, in the region of the rear of the engine and between the axes of rotation of the front and 95 rear wheels.

47 A vehicle as claimed in any one of the preceding claims, in which the drivable wheels of the vehicle are connected to be driven through a differential gear, 100 having an input shaft which extends upwardly.

48 A vehicle as claimed in any one of the preceding claims, in which the track width of all ground wheels of the vehicle 105 is adjustable.

49 A vehicle as claimed in any one of the preceding claims, in which each ground wheel comprises a wheel rim fastened to a wheel disc which has, as viewed in an axial 110 direction of the wheel, a substantially square circumference, fastening holes for the wheel rim being provided near the corners of the wheel disc.

A vehicle as claimed in claim 49, in 115 which the wheel discs are dished.

51 A vehicle as claimed in claim 50, in which each wheel disc can be fastened to a wheel hub in two positions, in one of which the cavity of the wheel disc is directed 120 inboard of the vehicle and in the other of which the cavity of the wheel disc is directed outwardly of the vehicle.

52 A vehicle as claimed in any one of claims 49 to 51, in which the wheel rim is 125 provided with fastening sleeves located to one side of the vertical plane of symmetry of the rim.

53 A vehicle as claimed in claim 52, in which each of the sleeves has an unin 130 1 603912 terrupted tapped hole.

54 A vehicle as claimed in claim 52 or 53, in which the rim can be fitted to the disc with either of the two end faces of the sleeves abutting the wheel disc.

A vehicle as claimed in any one of claims 52 to 54, in which each end face of each sleeve can be clamped through one of the holes of the whel disc against said wheel disc.

56 A vehicle as claimed in any one of the preceding claims, which is an agricultural tractor.

57 A tractor substantially as described herein with reference to and as illustrated 15 in the accompanying drawings.

HASELTINE LAKE & CO, Chartered Patent Agents, 28 Southampton Buildings, Chancery Lane, London, WC 2 A IAT and Temple Gate House, Temple Gate, Bristol B 51 6 PT also 9 Park Square, Leeds, L 51 2 LH.

Printed for Her Majesty's Stationery Office by The Tweeddale Press Ltd, Berwick-upon-Tweed, 1981.

Published at the Patent Office, 25 Southampton Buildings, London, WC 2 A l AY, from which copies may be obtained.