Electricity: circuit makers and breakers – Special application – Steering wheel – shaft or column mounted
Patent
1997-06-16
1998-11-10
Friedhofer, Michael A.
Electricity: circuit makers and breakers
Special application
Steering wheel, shaft or column mounted
200 4, 200 6127, H01H 2136
Patent
active
058347208
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
In heavy motor vehicles, e.g., agricultural machines and construction vehicles, the transmission is frequently adjusted by means of an electric switch. In this case, forward or reverse mode, originating from a neutral position, is adjusted with the aid of a first switch, with the individual gears being shifted by means of a second switch once the driving direction has been selected.
Known steering column switches are able to realize switching processes in two orthogonal planes. Consequently, steering column switches of this type can be used for selecting the driving direction as well for shifting the desired gears. For example, there exist steering column switches that initiate shifting processes by pivoting the shift lever, with said steering column switches comprising a rotary handle on the end of the manually actuated shift lever which makes it possible to adjust the desired shifting positions independently of the pivoting position of the shift lever. Such a switch, in which the driving direction, for example, is adjusted by pivoting the shift lever and the individual gears are shifted by correspondingly turning the rotary handle, is, in principle, quite suitable for use as a gear shifting mechanism.
However, it is imperative to prevent the driving direction from being unintentionally changed by actuating the shift lever while the transmission is in gear.
SUMMARY OF THE INVENTION
The invention is based on a steering column switch. An objective of the invention consists of ensuring that the switch which determines the driving direction cannot be unintentionally actuated in such a steering column switch that is used as a gear shifting mechanism.
This objective is attained by assigning the actuation of the shift lever in a first plane to the selection of the desired driving direction, with the actuation of the shift lever in a second plane serving for moving the shift lever from a fixed neutral position into an operating position, in which the driving direction can be changed, against a prestress. The switch according to the invention only allows a change in the driving direction if the shift lever is held in an operating position against the resistance of a spring and a transversely directed control movement of the shift lever is simultaneously carried out against the resistance of additional spring means. Consequently, it is practically ruled out for the shift lever to be unintentionally moved in both directions simultaneously, i.e., the driving direction can only be changed intentionally.
The described steering column switch is particularly suitable as a gear shifting mechanism if it is also provided with a rotary switch that is installed in its handle such that the driving direction can be changed and the transmission can be shifted into the desired gear with only one hand. In this case, the previously described locking function is preserved.
It is, in principle, possible for a pin that is connected to the holding element to engage into a corresponding recess for the driver when the holding element is moved into its second position such that a pivoting movement of the driver about its axis is blocked.
In order to securely hold the driver if stronger forces are exerted upon said driver, the invention proposes the additional refinement.
In order to ensure that the holding element is securely guided in the housing of the switch, the invention proposes that the holding element is provided with lateral guide grooves that are guided in the housing by means of corresponding guide rails. These characteristics make it possible to ensure that the holding element cannot be pivoted and block the actuation of the gear shifting mechanism.
The principle described thus far can generally be applied to all switches that can only be actuated if a locking mechanism is simultaneously rendered ineffective. In order to make it possible to utilize the described switch as a gear shifting mechanism, the shift lever is held in a (central) neutral position, from which it may only be laterally pivot
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English Translation of the International Preliminary Examination Report of Appl. No. PCT/EP95/03531.
Search Report of the German Patent Office for Application P4433595.4.
Klein Rudolf
Neubauer Walter
Friedhofer Michael A.
ITT Manufacturing Enterprises Inc.
Lewis J. Gordon
Twomey Thomas N.
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