Motor vehicles – Manually actuated controlling devices – With transmission control
Reexamination Certificate
2000-08-30
2001-11-20
Dickson, Paul N. (Department: 3618)
Motor vehicles
Manually actuated controlling devices
With transmission control
C074S473150, C074S473310
Reexamination Certificate
active
06318493
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle having a control mechanism for effecting a gear change in a vehicle, and is particularly applicable to a mechanism for controlling a forward/reverse shuttle mechanism in an agricultural tractor.
Agricultural tractors commonly have a lever for selecting the direction of travel, which is different from the lever for selecting the gear ratio. Having such a separate forward/reverse shuttle lever is convenient during low speed steering maneuvers, such as turning around a tractor towing a plough. In some vehicles, the shuttle can be operated without separately needing to operate a clutch during the gear changes.
Currently more sophisticated agricultural vehicles with electronically controlled transmissions, have an electrical or electronic forward/reverse shuttle control lever mounted on the steering column. On the other hand, vehicles with mechanically controlled transmissions currently have a mechanical lever located either on the left or right side of the tractor, depending upon the model of the vehicle.
SUMMARY OF THE INVENTION
The present invention seeks to provide a vehicle having a control mechanism for a mechanical gear box, especially a forward/reverse shuttle, that can be mounted on the steering column, so that a common position for the control mechanism may be adopted for vehicles having mechanically and electronically controlled gear boxes.
According to the present invention, there is provided a vehicle having a steering column, a gearbox forming part of the vehicle drive train and having a selection lever and a gear change mechanism mounted on the steering column for remotely operating the selection lever of the gearbox, wherein the gear change mechanism comprises a collar mounted for rotation about the axis of the steering column, a bevel gear fast in rotation with the collar, a second bevel gear meshing with the first bevel gear and mounted for rotation about a fixed axis that extends generally radially from the steering column, a crank arm connected for rotation with the second bevel gear and a flexible cable connecting the crank arm to the selection lever of the gearbox, the cable enabling the end of the selection lever to be pulled and pushed by rotation of the collar about the steering column.
Preferably, the collar is rotatable by a control lever that extends generally radially from the steering column and is mounted on the collar for pivotal movement in a plane containing the axis of the steering column and the radially inner end of the control lever extends through the collar into a shaped stationary groove that constrains the angular displacement of the collar about the axis of the steering column and the angular displacement of the control lever relative to the collar.
As earlier mentioned, the invention is especially intended for the forward/reverse shuttle of an agricultural vehicle. Such a gearbox has a selection lever with three positions corresponding to forward, neutral and reverse. In such a case, it desirable not to be able to overshoot the central neutral position and thereby switch directly between forward and reverse accidentally.
In one embodiment of the invention, the stationary groove may be Z shaped so that a gate is defined in the neutral position that has to be crossed by moving the end of the control lever parallel to the steering column before it can be used to rotate the collar about the steering column from the forward position to the reverse position.
In an alternative embodiment of the invention, the stationary groove may be T shaped and the control lever may be spring biased in its central position towards a locked position in which it cannot rotate the collar, so that neither forward nor reverse may be selected.
The groove needs to be stationary in relation to the steering column and to this end it may either be formed in the steering column or it may be formed in a ring surrounding the steering column that is itself suitably anchored to the body of the motor vehicle.
It is not necessary for the first and second bevel gears to be full gears as they are only rotated through a small angle and it would suffice for them to be toothed sectors or quadrants.
These and other objects, features and advantages are accomplished according to the instant invention in which an agricultural tractor is provided with a steering column, a gearbox forming part of the vehicle drive train and having a selection lever and a gear change mechanism mounted on the steering column for remotely operating the selection lever of the gearbox. The gear change mechanism comprises a collar mounted for rotation about the axis of the steering column, a first bevel gear fast in rotation with the collar, a second bevel gear meshing with the first bevel gear and mounted for rotation about a fixed axis that extends generally radially from the steering column, a rank arm
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connected for rotation with the second bevel gear, and a flexible cable connecting the crank arm to the selection lever of the gearbox, the cable enabling the end of the selection lever to be pulled and pushed by rotation of the collar about the steering column.
REFERENCES:
patent: 2861465 (1958-11-01), Winkle et al.
patent: 3417635 (1968-12-01), Day et al.
patent: 4635497 (1987-01-01), Siewert et al.
patent: 5797685 (1998-08-01), Jurik et al.
patent: 61-24620 (1986-02-01), None
Dickson Paul N.
Miller Larry W.
New Holland North America Inc.
Stader John William
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