TRACTOR

Abstract: Tractor with a transverse, approximately central wheel axle (12) having at each end a pair of radial pivotal arms (13) each carrying a tractor wheel (15) at the end facing away from the wheel axle (12). Between each arm (13) and the frame (10) of the tractor a hydraulic cylinder (16) is pivotally mounted to control the position of pivotment of the arm (13) such that, during cross-country driving, the driver's cab (11) is maintained in an approximately horizontal position.

Description: TRACTOR The present invention relates to a tractor with a wheel-mounted frame and, connected thereto, a driver's cab. Many kinds of cross-country vehicles are already known, with wheel-drive or caterpillar-d-ive. On the whole, they function well but are fairly complicated. It is the object of the present invention to provide a wheel-mounted tractor which is far less sophisticated, but nevertheless has excellent maneuvrability and is capable,. also when moving over rough ground, of main¬ taining ' the driver's cab in a more or less horizontal position. This object is achieved in that the tractor has a transverse, approximately centrally positioned wheel axle which at each' end is provided with radial arms pivotally supported independently of each other and carrying a wheel at the arm end facing away from the wheel axle, and in that a hydraulic cylinder is pi¬ votally connected to each arm and the frame at a point above the arm for controlling the position of pivotment of the arm relative to the wheel axle. The invention will be described in detail below, reference being had to the accompanying drawings which illustrate an embodiment and in which Fig. 1 is a lateral view of a tractor according to the invention, and Fig. 2 is a rear view of the tractor. The tractor shown in the drawings has, in conventional manner, a frame 10 and a driver's cab 11 connected thereto. The frame and the driver's cab can have any suitable form and must not necessarily be designed as shown in the drawings. Contrary to other tractors, the tractor according to the invention has only one wheel axle 12 which is hollow and approximately centrally positioned and in some suitable manner (not shown) is connected CMPI / to the frame 10. The wheel axle 12 projects on either side of the frame 1Q, as shown in Fig. 2, and on the projecting axle portions, on either side of the tractor, two arms 13 are pivotally supported at one end. The arms 13 are hollow and axially nondisplaceable on the axle 12 in that the arm end portion is disposed in a recess in the axle which at its extreme end has a detachable flange 21. The pivotal arms 13 have, at the end facing away from the axle- 12, a journal box 14 extending in parallel with the axle 12. In the box 14 a journal is mounted, carrying a tractor wheel 15. Inside the hollow axle 12, at each end thereof, a hydraulic motor is mounted for driving the tractor wheels 15, each motor being con¬ nected to two chain wheels which are positioned opposite the arms 13 on either side of the tractor. Around each chain wheel a chain is placed which extends through the associated hollow arm 13 and at the outer end of the arm is placed around a further chain wheel which is fixed¬ ly connected to the wheel journal mounted in the box 14. In this manner, one hydraulic motor drives the wheel pair on one side of the tractor, while the other hydraulic motor drives the wheel pair on the other side of the tractor, and since the motors are driven independently of each other, the tractor can be steered in this manner. In order to control the position of pivotment of the arms 13 pivotally mounted on the wheel axle 12, a hydraulic cylinder 16 is provided for each arm 13. The hydraulic cylinders IS arranged on either side of the tractor are pivotally mounted, at 19, in a bearing bracket 17 rigidly connected to the tractor frame 10 in a position directly above the axle 12. At 20, the piston rods of the hydraulic cylinders are pivotally connected to a bearing bracket 18 positioned on the upper side of each arm 13. When extending or retracting a hydraulic cylinder 16, its associated arm 13 mounted on the wheel axle 12 is pivoted, such that the wheel 15 of the arm can be raised or lowered, as shown by the dash and dot lines at 15' and 15' ' in Fig. 1. The hydraulic cylinders 16 are operable independently of each other, either manually or by means of a microcomputer system. During cross-country driving of the tractor accord- ' ing to the invention, each wheel may, as mentioned above, be displaced between the positions designated 15* and 15' ' independently of the other wheels, and this means that the tractor can be dfiven over extremely rough.and uneven ground, while maintaining the horizontal position of the driver's cab 11. For this purpose, the driver's cab preferably is equipped with a microcomputer sensing the longitudinal and transverse tilting tendency of the driver's cab and activating one or more hydraulic cylin- ders to eliminate tilting. Since the tractor has but one wheel axle, construction costs are reduced and, fur¬ thermore, the maneuvrability is improved owing to the increased ground clearance.

Claims: CLAIMS 1. Tractor with a wheel-mounted frame (10) and, connected thereto, a driver's cab (11), c a r a c ¬ t e r i s e d in that the tractor has a transverse, approximately centrally positioned wheel axle (12) which at each end is provided with radial arms (13) pivotally supported independently of each other carrying a wheel at the arm end facing away from the wheel axle (12) , and in that a hydraulic cylinder (16) is pivotally connected to each arm (13) and the frame (10) at a point above the arm (13) for controlling the position of pivot ent of the arm (13) relative to the wheel axle (12) . 2. Tractor as claimed in claim 1, c h a r a c ¬ t e r i s e d in that the hydraulic cylinders (16) on either side of the tractor are pivotally mounted in a bearing bracket (17) directly above the wheel axle (12). 3. Tractor as claimed in claim 1 or 2, c h a r ¬ a c t e r i s e d in that means are provided to maintain the driver's cab (11) in an approximately horizontal position by individually controlling the wheel arms (13) by means of the hydraulic cylinders (15). 4. Tractor as claimed in any one of the preceding claims, c h a r a c t e r i s e d in that the wheel axle (12) is hollow and has at each end a hydraulic motor adapted to drive the tractor wheels (15) by means of chains placed in the arms (13) which also are hollow.

Inventors: PERSSON KJELL OLOF, PERSSON, KJELL, OLOF
Applicants: HAEGLINGE IND AB, HAEGLINGE INDUSTRI AB
Application year: 1984
Main classification: B62D49
IPC codes: B60G17, B62D49