EP0000211A1

EP0000211A1 - Tracked vehicles

Info

Publication number: EP0000211A1
Application number: EP78200010A
Authority: EP
Inventors: Cornelis Van Der Lely
Original assignee: C Van der Lely NV
Current assignee: C Van der Lely NV
Priority date: 1977-06-24
Filing date: 1978-06-01
Publication date: 1979-01-10
Also published as: EP0000211B1; DE2861713D1; NL7707007A

Abstract

The invention relates to vehicles, such, for example, as tractors, trucks, cars, vehicular soil cultivating machines or the like, of the kind which comprise at least one endless track arranged around ground wheels of the vehicle. The track of a vehicle of this kind comprises a belt of flexible material and has a plurality of profiles/ridges which are directed forwardly with respect to the direction of relative movement of the track for forward travel of the vehicle.

Description

The invention relates to vehicles, such, for example, as tractors, trucks, cars, vehicular soil cultivating machines or the like of the kind which comprise at least one endless track arranged around ground wheels of the vehicle.
An object of the invention is to provide a track that has an increased resistance to slipping and skidding relative to known vehicle-track combinations.
According to the invention the track comprises a belt cf flexible material and has a plurality of profiles/ridges which are directed forwardly with respect to the direction of relative movement of the track for forward travel of the vehicle.
For a better understanding of the invention, and to show how the same may be carried into effect, reference will be made, by way of example, to the accompanying drawings, in which:-

Figure 1 is a side elevation of a tractor in accordanc with the invention,
Figure 2 is a plan view of the tractor of Figure 1,
Figure 3 is a side elevation to an enlarged scale of part of the rear of the tractor as seen in the direction of the arrow III-III in Figure 2,
Figure 4 is a part sectional elevation . taken on the line IV-IV in Figure 3.

The vehicle shown in Figure 1 comprises a frame 1 having two substantially horizontal and relatively parallel frame beams 2, the frame 1 being supported by steerable front wheels 3 and by two pairs of rear wheels 4 and 5 arranged one behind the other on either side of the vehicle. The two foremost rear wheels 4 and the hindmost rear wheels 5 are in line behind the former considered in the direction A and are provided with tyres 6 having conventional profiles. The front wheels 3 are also provided with tyres. The diameter of the foremost rear wheels 4 is substantially equal to that of the hindmost rear wheels 5. In this embodiment, the diameter of the front wheels 3 is equal to that of the rear wheels 4 and 5 but the diameter of the front wheels 3 may be larger or smaller than that of the rear wheels. Axles 7 of the front wheels 3 are fastened through steerable pivot pins or kins pins 8 to a front axle beam 9 extending perpendicular to the direction A, the beam 9 being freely pivotable in a vertical plane of substantial symmetry of the tractor on a horizontal pivot shaft 10 extending in the direction A, and being journalled in a support fastened to a transverse beam 11 which interconnects the front ends of the longitudinal frame beams 2. Viewed from one side (Figure 1) the pivotal shaft 10 is located substantially midway between the top and bottom of the transverse beam 11. wheel axles 12 of the foremost rear wheels 4 and wheel axles 13 of the hindmost rear wheels 5 are supported, for the wheels 4 and 5 on one side of the tractor, in a beam 14 extending parallel to the direction A and being located alongside the corresponding frame beam 2. The supporting beam 14 is freely pivotable about a shaft 15 which extends horizontally perpendicular to the direction A and which is located beneath the bottoms of the frame beams 2. The two supporting beams 14, together with the rear wheels coupled thereto, are freely pivotable about the shaft 15. The pivotal shaft 15 is located on one side of the aforementioned vertical plane of.substantial symmetry between the wheel axles 12 and 13, that is to say, between said plane and the corresponding wheel axle 13. The foremost rear wheels 4 are freely rotatable on the axles 12. The two wheel axles 13 are extended in the space between the two supporting beams 14 and are coupled together by differential gear 16 which has an upwardly extending input shaft coupled with the output shaft of a torque converter 17, the latter being pivotable to a limited extend relative to the frame 1 of the tractor and being connected to said frame. The torque converter 17 is located, viewed in side elevation wholly or partly above the/hindmost rear wheels 5. The connec- tion between the output shaft of the torque converter 17 and the input shaft of the differential 16 is telescopic in view of potential movements of the supporting beams 14. The torque converter 17 may comprise two pairs of adjustable wheel discs, said pairs being interconnected by a chain so that, by relative adjustment of each of the pairs of wheel discs, a continuously variable transmission can be obtained. The torque converter 17 comprises an input shaft which can be driven through an auxiliary shaft 18 by the tractor engine 19, the auxiliary shaft 18 preferably being telescopic and being provided with two universal joints 20 so that relative movements of-the torque converter 17 and the tractor engine 19 are possible.
The front wheels 3 are steerable from a driver seat 2-1, which is located, as seen in Figure 1, at a distance above the top point of the: rear wheels 4 and 5 and, viewed in plan (Figure 2), in the position shown in Figure 1 between the wheel axles 12 and 13. The driver seat 21 is fastened to a console 22, to which is fastened, moreover, a column 23 provided with a steering wheel 24 and all further steering and control-members. The assembly of the seat 21, the console 22, the column 23, the steering wheel 24 and all further steering and control-members is pivotable as a whole about a substantially vertical pivotal shaft 25 located in the vertical plane of substantial symmetry of the tractor. The assembly can be fixed in two positions differing by 180° around the axis of said shaft 25 so that the front of the seat 21 faces in the direction of forward travel A o in the opposite direction. The driver seat 21 is surrounded by a cabin
26 extending, as seen in Figure 1, above the rear wheels 4 and 5.
The rear of the tractor shown in Figure 1 has a three-point lift 27 which can be hydraulically energized from the driver seat 21. Viewed in Figure 1, those parts of the two frame beams 2 which are located between the rear regions of the front wheels 3 and the front regions of the rear wheels 4 are provided on either side of the tractor with a lifting device 28 , the lower lifting arms 29 of which are connected to the bot- toms of the francbeams 2 so as to be pivotable about horizontal shafts 30 extending in the direction A by hydraulic agency from the driver seat 21. The top arm 29Aof the lift 28bears from thedriver seat 21. Thetoparm 29A ofthelift28bears on the top of the adjacent frame beam 2.
A front three-point lift 31 comprises lower lifting arms 32 and a top lifting arm 33arranged to pivot about substantially horizontal shafts 34 and 35 respectively, said shafts extending perpendicular to the direction A and being journalled in a support 36located at a smalldistance in front of the front axle 9. The lifting device 31can also be actuated from the driver seat 21 by hydraulic agency. The support 36 is fastened in position by two arms 37 extending away from the support 36 to the rear. Each of the arms 37 is located, as seen in Figure 1, ,at a small distance above the top of the adjacent frame beam 2 and, as seen in Figure 2, on the outer: side of the corresponding frame beam 2. Near the rearmost ends of the arms 37, which are located, viewed in plan, about midway across the space between the wheel axles 7 and 12, said arms are provided with fastening lugs 38holding horizontal pivotal shafts 39 extending perpendicular to the direction A. Each of the pivotal shafts 39 is fastened to the side of the adjacent frame beam 2. The joint between each pivotal shaft 39 and.the associated lug 38 is preferably movable, for example, by means of a ball hinge arranged in a comparatively large rubber support socket in the lug 38. Ata short distance behind the support 36 the bottom of each arm 37 bears;' on the top of the front

membereon that side. On the

the cavity 50, a further cavity

embodiment as a mirror image of thecavity 50.
cavity, in the direction B, provides, in the disposition, shown an increased flexibility of the supporting part 48with respect to the belt 45 and said cavity has the same function as the cavity50 when the caterpillar 44 is applied to the wheelsin
Figure 4 shows that the belt 45 is provided witha liner comprising a large number of coplanar,parallel steel wires 51 extending parallel to the direction of length of the caterpillar track 44, said wires being endless on a circular path. These steel wires 51 are interconnected by a large number of steel wires 52 extending parallel to one another in the direction of width of the caterpillar track 44. The steel wires 52 are preferably fastened to the steel wires 51 crossing the same at right angles so that a network is formed Instead of using steel wires, strong synthetic plastics or other fibres may be employed. The network of steel wires 51 and52 is embedded in the material of the belt 45. The belt 54, the teeth or cams 45 and the transverse ridges 47 are integral and made from a single piece of flexible material, for example, a synthetic resin or a rubber-like material. During operation, the tractor engine 19 drives only the axles 13 of the hindmost rearwheels 5 through the auxiliary shaft 18, the variable torque converter 17 and the differential 16. With a direction of rotation of the rear wheels 5 corresponding with the direction A, the driving moment of each wheel axle 13 is transmitted through a wheel disc 53 (Figure 4) to a wheel flange 54 holding wheel rims 55 of the tyres 6. upon rotation, the tyres carry along the teeth or cams 46 locates between them so that each caterpillar track 44 is rotated. The foremost rear wheels 4 are driven solely by the caterpillar tracks 44. The tractive run of each caterpillar tracK 44 is located on the ground and is vigourously drawn rearwardly