Shift lever interlock system

• US 5,289,907 A
• Filed: 01/25/1993
• Issued: 03/01/1994
• Est. Priority Date: 06/11/1990
• Status: Expired due to Fees

• Current Assignee: Sparton Engineered Products, Inc.
• Original Assignee: Sparton Corporation (Elbit Systems Limited)
• Inventors: Pattock, Greg R.
• Primary Examiner(s): Lorence, Richard M.
• Application Number:
  US08/008,527
• Time in Patent Office: 400 Days
• Field of Search: 192/4 R, 192/4 A, 192/4 C, 74/483 R, 74/483 K, 74/878, 70/245, 70/247, 70/248, 70/254, 180/271
• US Class Current: 192/220.3
• CPC Class Codes: F16H 2059/746 Engine running state, e.g. on-off of ignition switch
• CPC Class Codes: F16H 2061/223 Electrical gear shift lock, e.g. locking of lever in park or neutral position by electric means if brake is not applied; Key interlock, i.e. locking the key if lever is not in park position
• CPC Class Codes: F16H 59/10 comprising levers
• CPC Class Codes: F16H 59/54 dependent on signals from the brakes, e.g. parking brakes
• CPC Class Codes: F16H 61/22 Locking of the control input devices constructional features of locking or disabling mechanisms F16H63/34
• CPC Class Codes: Y10T 70/5938 With switch
• CPC Class Codes: Y10T 74/20238 Interlocked

Abstract

The shift lever interlock system combines a shift lever position signal, interlock actuator extend and retract signals and vehicle system input signals (e.g., representing the service brake, ignition key-in, ignition circuit and vehicle battery voltage level) in a logic control circuit to lock the shift lever in the "Park" position, except if the ignition key is not in the "Lock" position and the service brake is depressed (applied) or the voltage of the battery is too low. The interlock system is not actuated to lock the shift lever in position when the shift lever is in positions other than as retained in the "Park" position by the detent mechanism.

Claims

1. A shift lever interlock system for a vehicle having a transmission with a shift lever, comprising:

a shift lever means movable between a non-drive position and a drive position,

detent means for releasably retaining the shift lever means in a selected position,

an electrical actuator for moving a locking member to a locking position relative to the detent means when the shift lever is retained in the non-drive position by the detent means to prevent movement of the shift lever by the vehicle operator,

an ignition switch mechanism for providing an ignition switch input signal indicative of whether the ignition switch is in a lock or non-lock position,

a service brake system switch means for providing a brake system input signal indicative of whether the service brake system is in a brake applied or brake release mode,

an under-voltage sensor associated with a battery of said vehicle for providing a battery level input signal indicative of whether the battery is in a low voltage or non-low voltage condition and,

means for providing a shift lever position input signal indicative of whether said shift lever is or is not retained in the non-drive position by the detent means,

a control circuit for controlling the actuator in response to said input signals to lock the shift lever in position if the shift lever is retained in the non-drive position by said detent means and the ignition switch is in the lock condition and to unlock the shift lever when the ignition switch is in the unlock condition and the brake system is in the brake release mode or when the ignition switch is in the unlock condition and the battery is in the low voltage condition.

2. The system of claim 1 wherein the locking member is positioned beneath the detent means when said locking member is in said locking position.

3. The system of claim 1 wherein the actuator comprises a bidirectional electrical motor.

4. The system of claim 3 wherein the bidirectional motor drives a pinion for reciprocating a rack, said locking member being coupled to said rack.

5. The system of claim 1 wherein said actuator includes means for providing a first input signal representative of said locking member being in the locking position and means for providing a second input signal representative of said locking member being in an unlocking position relative to said detent means.

6. The system of claim 1 wherein said means for providing a first input signal and means for providing a second input signal comprise respective first and second sets of spaced apart electrical contacts on said actuator and respective first and second electrical contacting members disposed on said locking member for movement therewith such that said first contacting member engages said first set of contacts when the locking member is in the locking position and said second contacting member engages aid second set of contacts when the locking member is in the unlocking position.

7. The system of claim 1 wherein said means for providing a shift lever position input signal comprises a shift lever switch means adjacent said detent means for actuation by said detent means when the shift lever is retained in the non-drive position by said detent means.

8. A shift lever interlock system for a vehicle having a transmission with a shift lever movable to drive and non-drive positions and having a service brake and a battery, said interlock system comprising:

a locking member movable into a locking position to prevent movement of said shift lever from said non-drive position, and movable to an unlocking position to permit movement of said shift lever to said drive positions,

an actuator mechanism for moving said locking member between said unlocking position and said locking position,

said actuator mechanism being operative to move the locking member into said locking position in response to positioning of said lever in said non-drive position,

said actuator mechanism being operative to move the locking member to the unlocking position in response to actuation of said service brake, and

a low voltage detector coupled with said battery and operatively coupled with said actuator mechanism for disabling said locking member from preventing movement of said shift lever from said non-drive position in response to battery voltage lower than a predetermined value.

9. The system of claim 8 wherein said actuator comprises a bi-directional electrical motor.

10. The system of claim 8 including an ignition switch mechanism operatively coupled with said actuator mechanism for disabling said locking member from preventing movement of said shift lever from said non-drive position in response to the ignition switch mechanism being in a non-locked position when said service brake is actuated and said battery voltage is not lower than said predetermined value.