Rear link control

Abstract

A suspended axle for a tractor, the axle having a lower link mechanism selectively operable between a first configuration in which the lower links are in fixed relation to the suspended axle and a second configuration in which the lower links are isolated from the suspended axle.

Claims

1. A suspended axle for a tractor, the suspended axle configured to pivot on a chassis of the tractor about a suspended axle pivot, the axle comprising: a lower link mechanism selectively operable between a first configuration in which lower links of the lower link mechanism are in fixed relation to the suspended axle and a second configuration in which the lower links are isolated from the suspended axle, wherein the lower link mechanism is selectively operable by actuation of a link connected to a lift arm lever between a first position in which a first end of the link coincides with the suspended axle pivot and a second position in which the first end of the link is distal from the suspended axle pivot.

2. The suspended axle of claim 1 wherein the suspended axle has a rear axle arm which carries the lift arm lever pivotally attached to an upper end of a lift arm.

3. The suspended axle of claim 2 wherein a lower end of the lift arm is connected to the lower links.

4. The suspended axle of claim 1 wherein the link is actuable by a first end of an isolation arm.

5. The suspended axle of claim 4 wherein a second end of the isolation arm is pivoted on the tractor chassis and is actuable by a hydraulic actuator.

6. An agricultural tractor comprising a suspended axle as claimed in claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will now be described, by way of example only, and with reference to the following drawings, in which:

(2) FIG. 1 is a schematic side view of the suspended axle of the present invention shown in a first position;

(3) FIG. 2 is a schematic side view of the suspended axle of FIG. 1 shown in a second position; and

(4) FIG. 3 is a side view of an agricultural tractor having a suspended axle according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

(5) FIGS. 1 and 2 show a suspended rear axle 10 for a tractor with full independent suspension. The rear axle 10 is pivoted on the tractor chassis indicated generally at 12 at pivot 14. The rear axle arm 16 carries a rear differential centred at point A. At the rear end of the rear axle arm 16 is a flange 18 that supports rear links 20. The opposite end of the rear links 20 are supported by rear lift arms 22 the upper end of which is attached to a lift arm lever 24 which is pivoted on an upper extension 26 of the rear axle arm 16. The opposite end of the lift arm lever 24 is connected to a link 28 which is moveable under the action of an isolation arm 30. The isolation arm 30 is actuated by an actuator 32 between its first position shown in FIG. 1 and its second position shown in FIG. 2.

(6) In FIG. 1, rotation of the rear axle arm 16 in an upward direction in response to changing terrain along arc B causes a consequential rotation of the rear link 20 along the same arc since the connection between the isolation arm 30 and link 28 is coincidental with the rear axle arm pivot 14.

(7) In contrast, in FIG. 2, rotation of the rear axle arm 16 in an upward direction along the same arc B does not lead to the same displacement of the rear link due to the establishment of a four bar linkage resulting from the movement of the link 28 to its new position. In this configuration the rear link is caused to move in an upward direction C. This direction C more closely matches the profile of the terrain (ie an upward deflection) than does the movement of the rear link in the first configuration shown in FIG. 1.

(8) This allows the rear link, and, as a result the implement being carried on the rear linkage, to more closely match the terrain. This allows the tractor to match the rear link operation to the nature of the work being undertaken, in particular matching the requirements of the implement during on-road and on-field conditions.

(9) An agricultural tractor 100 is illustrated in FIG. 3. The tractor 100 comprises front wheels 102, rear wheels 104, an engine section 106 and a cab section 108. The engine section 106 comprises a tractor engine 110 and an engine cooling system 112 located adjacent thereto. The rear link 20 of FIGS. 1 and 2 is provided towards the rear of the tractor 100. The tractor 100 may comprise a chassis or frame to which components may be attached or mounted.

(10) In one aspect, the suspended axle mechanism shown in FIGS. 1 and 2 is provided as a component of a tractor 100. In an alternative aspect, the suspended axle mechanism may be provided as a retrofit solution for an existing tractor 100.

(11) The invention is not limited to the embodiment described herein, and may be modified or adapted without departing from the scope of the present invention.