Vehicle control system with conditional transmission-brake interlock
First Claim
1. In a control system for a vehicle (12, 12a) having a drive transmission (16, 16a) which may be shifted between a neutral non-drive transmitting condition and at least one drive transmitting condition and having a brake (29, 29a) which may be engaged and disengaged, and having a control element (32, 32a) which is operated in conjunction with initiating travel of the vehicle, the control system including neutralizing means (19, 19a) for maintaining said transmission in said neutral condition in response to a neutralizing signal and further including a transmission and brake interlock circuit means (39, 39a) for holding said transmission in said neutral condition by transmitting said neutralizing signal to said neutralizing means if said control element is operated while said brake is engaged, the improvement comprising:
- interlock control circuit means (51, 51a) for inactivating said interlock circuit means during travel of said vehicle by blocking transmission of said neutralizing signal from said interlock circuit means to said neutralizing means to enable engagement of said brake without neutralization of said transmission when said vehicle is traveling.
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Abstract
In a vehicle (12, 12a) having interlock means (39, 39a) for maintaining the vehicle transmission (16, 16a) in neutral if powered travel is attempted while the parking brake (29, 29a) is engaged, interlock control means (51, 51a) are provided for inactivating the interlock once the vehicle is undergoing powered travel. If it becomes necessary to use the parking brake to stop motion of the vehicle, the retarding action of the engine (13, 13a) is effective, through the still engaged transmission, to supplement such emergency use of the parking brake.
22 Citations
9 Claims
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1. In a control system for a vehicle (12, 12a) having a drive transmission (16, 16a) which may be shifted between a neutral non-drive transmitting condition and at least one drive transmitting condition and having a brake (29, 29a) which may be engaged and disengaged, and having a control element (32, 32a) which is operated in conjunction with initiating travel of the vehicle, the control system including neutralizing means (19, 19a) for maintaining said transmission in said neutral condition in response to a neutralizing signal and further including a transmission and brake interlock circuit means (39, 39a) for holding said transmission in said neutral condition by transmitting said neutralizing signal to said neutralizing means if said control element is operated while said brake is engaged, the improvement comprising:
interlock control circuit means (51, 51a) for inactivating said interlock circuit means during travel of said vehicle by blocking transmission of said neutralizing signal from said interlock circuit means to said neutralizing means to enable engagement of said brake without neutralization of said transmission when said vehicle is traveling.
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2. In a control system for a vehicle (12, 12a) having a drive transmission (16, 16a) which may be shifted to a neutral non-drive transmitting condition and having a brake (29, 29a) which may be engaged and disengaged, and having a control element (32, 32a) which is operated in conjunction with initiating travel of the vehicle, the control system including a transmission and brake interlock (39, 39a) for holding said transmission in said neutral condition if said control element is operated while said brake is engaged, and wherein said vehicle (12, 12a) has a source (34, 34a) of electrical current and has electrically actuated neutralizing means (15, 15a) for neutralizing said transmission and wherein said interlock (39, 39a) includes an interlock switch (46, 46a) connected between said source of current and said electrically actuated neutralizing means and which is coupled to said brake (29, 29a) to operate in conjunction therewith to transmit an electrical actuating signal to said neutralizing means when said brake is engaged and to block said electrical actuating signal from said neutralizing means when said brake is disengaged, the improvement comprising:
interlock control means (51, 51a) for inactivating said interlock during travel of said vehicle to enable engagement of said brake without neutralization of said transmission when said vehicle is traveling, wherein said interlock control means (51, 51a) includes override switch means (48, 48a) connected in series with said interlock switch (46, 46a) and which is responsive to movement of said control element (32, 32a) to transmit said electrical signal to said interlock switch when said control element is operated to initiate travel of said vehicle (12, 12a). - View Dependent Claims (3, 4, 5, 6)
- 7. A drive control system for a vehicle which has a transmission for coupling an engine to ground engaging means in at least one drive mode of operation and for decoupling said engine from said ground engaging means in a neutral condition and having neutralizing means for establishing said neutral condition in response to a neutralizing signal, said vehicle having a parking brake and having a control element which is actuated to begin powered travel of said vehicle from a stationary condition, said vehicle further having an interlock for transmitting said neutralizing signal to said transmission if said control element is actuated at a time when said brake is engaged, further comprising interlock control means for blocking transmitting of said neutralizing signal to said transmission through said interlock during powered travel of said vehicle.
Specification