Patent ID: 6376929
Filing Date: 2002-04-23
Classification: F16H

Abstract:
An electronic fail-safe position switch apparatus adapted for mechanical connection to a gear select device for a transmission and electrically connected to a controller for receiving electrical signals from a plurality of signal lines electrically connected to the electronic fail-safe position switch apparatus and for controlling a selection of a gear from among a plurality of gears housed in the transmission as a function of a combination of received electrical signals, a different combination of electrical signals being associated with a particular one of the gears, the electronic fail-safe position switch apparatus comprising:a position switch having a plurality of operating positions with each operating position associated with a different one of a plurality of combinations of electrical signals in a normal state, the plurality of operating positions including a plurality of range positions with a respective range position being associated with a respective particular gear and a respective particular combination of electrical signals and a plurality of intermediate positions unassociated with any particular gear in the normal state but each intermediate position being associated with a respective particular combination of electrical signals, a respective one of the intermediate positions being disposed between consecutive ones of the range positions, wherein, in a fault state where one of the signal lines fails, at least two of the combinations of electrical signals associated with their respective operating positions change while remaining ones of the combinations of electrical signals associated with their respective operating positions remain the same in the fault state as in the normal state, at least one of the at least two of the combinations of electrical signals that changes in the fault state is identical to one of the remaining ones of the combination of electrical signals, the operating position associated with the at least one of the at least two of the combinations of electrical signals that changes is disposed immediately adjacent to an operating position associated with one of the remaining ones of the combinations of electrical signals that did not change and wherein, other ones of the at least two of the combinations of electrical signals that change in the fault state are different from all combinations of electrical signals existing after failure of the one signal line.