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US 5,853,348 AGranted
Park position locking system for steering column transmission shifter
AssigneeNavistar International Transportation Corp.
InventorMichael J. Lehman
Life of this patent
Estimating the term…
Abstract
A system for selectively locking a steering-column-mounted transmission shifter in a park position that places the transmission in one of two neutral positions. An electrically operated shift lock releasably locks the shifter in park position. The shift lock is under the control of an electric circuit that contains first and second shift lock relays having normally open contacts connected in series to the shift lock. The electric circuit operatively couples the relays' coils with the ignition switch, a transmission neutral position sensing switch, and a service brake sensing switch. When the service brakes are applied and the ignition switch is on, the shift lock is operated to release the shifter, allowing the shifter to be moved to other positions.
Claims15
An automotive vehicle comprising:
- a) a powertrain that includes a transmission that is shiftable to plural positions, two of which are NEUTRAL positions;
- b) a shifter disposed for operation by a driver of the vehicle for selectively shifting the transmission to its plural positions;
- c) service brakes;
- d) parking brakes;
- e) an electrical system comprising a battery and an ignition switch that when operated to ON position provides battery voltage at an ignition switch ON terminal;
- and
- f) a system for selectively locking the shifter in a PARK position that places the transmission in one of its two NEUTRAL positions, wherein the system comprises,
- 1) an electrically operated shift lock for releasably locking the shifter in PARK position,
- 2) a first controlled conductivity device;
- 3) a second controlled conductivity device;
- and
- 4) electric circuitry operatively coupling the shift lock with the transmission and the service brakes comprising a transmission NEUTRAL position sensor that distinguishes between the transmission being in either of its two NEUTRAL positions and not being in either of its two NEUTRAL positions, a service brake sensor that distinguishes between the service brakes being applied and not being applied, a first circuit placing the conductivity of the first controlled conductivity device under the control of the transmission NEUTRAL position sensor, a second circuit placing the conductivity of the second controlled conductivity device under the control of the service brake sensor, and a third circuit placing control of the electrically operated shift lock under the control of both the first controlled conductivity device and the second controlled conductivity device.
9 more elements
For use in an automotive vehicle comprising
- a) a powertrain that includes a transmission that is shiftable to plural positions, two of which are NEUTRAL positions,
- b) a shifter disposed for operation by a driver of the vehicle for selectively shifting the transmission to its plural positions,
- c) service brakes,
- d) parking brakes,
- e) an electrical system comprising a battery and an ignition switch that when operated to ON position provides battery voltage at an ignition switch ON terminal;
- a system for selectively locking the shifter in a PARK position that places the transmission in one of its two NEUTRAL positions, the system comprising:
- 1) an electrically operated shift lock for releasably locking the shifter in park position,
- 2) a first controlled conductivity device;
- 3) a second controlled conductivity device;
- and
- 4) electric circuitry for operatively coupling the shift lock with the transmission and the service brakes comprising a transmission NEUTRAL position sensor for distinguishing between the transmission being in either of its two NEUTRAL positions and not being in either of its two NEUTRAL positions, a service brake sensor for distinguishing between the service brakes being applied and not being applied, a first circuit for placing the conductivity of the first controlled conductivity device under the control of the transmission NEUTRAL position sensor, a second circuit for placing the conductivity of the second controlled conductivity device under the control of the service brake sensor, and a third circuit for placing control of the electrically operated shift lock under the control of both the first controlled conductivity device and the second controlled conductivity device.
8 more elements
In an automotive vehicle comprising
- a) a powertrain that includes a transmission that is shiftable to plural positions, two of which are NEUTRAL positions;
- b) a shifter disposed for operation by a driver of the vehicle for selectively shifting the transmission to its plural positions;
- c) service brakes;
- d) an electrical system comprising a voltage source and an ignition switch that when operated to ON position provides voltage at an ignition switch ON terminal;
- a system for selectively locking the shifter in a PARK position that places the transmission in one of its two NEUTRAL positions, the system comprising,
- 1) an electrically operated shift lock for releasably locking the shifter in PARK position,
- 2) a first controlled conductivity device;
- 3) a second controlled conductivity device;
- and
- 4) electric circuitry for operatively coupling the shift lock with the transmission and the service brakes comprising a transmission NEUTRAL position sensor for distinguishing between the transmission being in either of its two NEUTRAL positions and not being in either of its two NEUTRAL positions, a service brake sensor for distinguishing between the service brakes being applied and not being applied, a first circuit placing the conductivity of the first controlled conductivity device under the control of the transmission NEUTRAL position sensor, a second circuit placing the conductivity of the second controlled conductivity device under the control of the service brake sensor, and a third circuit placing control of the electrically operated shift lock under the control of both the first controlled conductivity device and the second controlled conductivity device.
7 more elements
Dependencies are inferred from the claim text.