Controller for a movable motor vehicle headlamp mechanism

• US 4,558,259 A
• Filed: 01/09/1984
• Issued: 12/10/1985
• Est. Priority Date: 01/09/1984
• Status: Expired due to Term

• Current Assignee: General Motors Acceptance Corporation (Ally Financial, Inc.)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Craig, Gale M.
• Primary Examiner(s): Chatmon, Saxfield
• Application Number:
  US06/569,221
• Time in Patent Office: 701 Days
• Field of Search: 362/65, 362/66, 307/10 LS, 315/82, 315/83, 318/255, 318/256, 318/257, 318/258, 318/280, 318/282, 318/459, 318/468, 318/264, 318/265, 318/266, 318/145, 318/331, 318/368
• US Class Current: 315/82
• CPC Class Codes: B60Q 1/05 retractable

Abstract

A control unit for operating the motor of a motor driven headlamp carrier mechanism includes oscillator circuitry for generating a series of pulses for energizing the motor, voltage responsive means for sensing a motor counter-EMF related voltage as an indication of motor rotation, output circuitry for interrupting motor energization when the voltage responsive circuitry senses motor stall, and start circuitry for energizing the motor independent of the oscillator circuitry for a period of time sufficient to produce motor counter-EMF. Such control permits sensing of the engagement of the headlamp carrier with fixed mechanical stops without the use of position or torque limit switches.

Claims

1. In a motor vehicle lighting system including a headlamp, an operator manipulated headlamp switch, movable concealment means, a source of direct voltage, and an electric motor connected to said concealment means and adapted to be energized with said source for moving the concealment means into engagement with a mechanical stop to fully expose the headlamp, the improvement comprising:

oscillator means for generating a series of pulses in response to operator manipulation of headlamp switch;

run means operative to energize said motor with said source in accordance with the pulses generated by said oscillator means for moving the concealment means toward the mechanical stop;

voltage responsive means for sensing a motor counter-EMF related voltage as an indication of motor rotation and for generating a stall signal when the motor counter-EMF falls substantially to zero indicating that the motor speed has fallen substantially to zero, whereby engagement of the concealment means with the stop is sensed without the use of a limit switch to sense such engagement;

stop means for inhibiting further operation of said run means in response to the generation of a stall signal by said voltage responsive means thereby to interrupt motor energization after the motor moves the concealment means into engagement with said mechanical stop; and

start means initiated in response to operator manipulation of said headlamp switch for energizing said motor independent of said run means for a period of time sufficient in duration to produce motor rotation for increasing the motor counter-EMF substantially above zero, whereafter motor energization is controlled by said run means, said voltage responsive means and said stop means.

2. A motor vehicle lighting system according to claim 1 including:

means for inhibiting operation of said run means a predefined period of time after the operator manipulation of the headlamp switch, thereby to prevent continued motor energization in the event that the motor becomes disconnected from the concealment means.

3. In a motor vehicle lighting system including movable concealment means for a headlamp, a source of direct voltage, an electric motor adapted to be energized with said source for moving the concealment means into engagement with first or second mechanical stops to fully expose or conceal the headlamp, and a headlamp switch operator manipulatable to an ON position to energize the headlamp or an OFF position to de-energize the headlamp, the improvement comprising:

oscillator means for generating a series of pulses in response to operator manipulation of the headlamp switch;

run means operative to energize said motor with said source in accordance with the pulses generated by said oscillator means for moving the concealment means toward the first mechanical stop to expose the headlamp if the headlamp switch is in the ON position and toward the second mechanical stop if the headlamp switch is in the OFF position;

voltage responsive means for sensing a motor counter-EMF related voltage as an indication of motor rotation and for generating a stall signal when the motor counter-EMF falls substantially to zero indicating that the motor'"'"'s speed has fallen substantially to zero, whereby engagement of the concealment means with the stops is sensed without the use of a limit switch to sense such an engagement;

stop means for inhibiting further operation of said run means in response to generation of a stall signal by said voltage responsive means thereby to interrupt motor energization after the motor moves the concealment means into engagement with said stops;

start means initiated in response to operator manipulation of the headlamp switch for energizing the motor independent of said run means for a period of time sufficient in duration to produce motor rotation for increasing the motor counter-EMF substantially above zero whereafter motor energization is controlled by said run means, said voltage responsive means and said stop means; and

means for interrupting energization of said motor to prevent further movement of said concealment means if the motor is energized for moving the concealment means toward the second mechanical stop to conceal the headlamp while the headlamp switch is in the ON position.

4. In a motor vehicle lighting system including an operator manipulated headlamp switch, a movable carrier for a headlamp, a source of direct voltage and an electric motor connected to said carrier and adapted to be energized with said source for moving the carrier into engagement with a mechanical stop to fully expose the headlamp, a method of operation comprising the steps of:

energizing the motor for a predetermined period of time to move the carrier toward the mechanical stop in response to operator manipulation of the headlamp switch, such predetermined period of time being sufficient in duration to produce motor rotation that increases the motor counter EMF substantially above zero; and

thereafter

continuing the motor energization in a series of pulses for producing further movement of the headlamp carrier;

sensing a motor counter-EMF related voltage as an indication of motor rotation and generating a stall signal when the motor EMF falls substantially to zero indicating that the motor speed has fallen substantially to zero whereby engagement of the carrier with the stop is sensed without the use of a limit switch to sense such engagement; and

interrupting energization of the motor in response to the generation of a stall signal thereby to prevent further energization of the motor after the carrier has been moved into engagement with the mechanical stop.

5. A method of operation as set forth in claim 4 including the step of:

de-energizing the motor a predefined period of time following the operator manipulation of the headlamp switch thereby to prevent continued motor energization in the event that the motor becomes disconnected from the headlamp carrier.

6. In a motor vehicle lighting system including a movable carrier for a headlamp, a source of direct voltage, an electric motor adapted to be energized with said source for moving the carrier into engagement with first or second mechanical stops to fully expose or conceal the headlamp, and a headlamp switch operator manipulatable to an ON position to energize the headlamp or an OFF position to de-energize the headlamp, a method of operation comprising the steps of:

energizing the motor for a predetermined period of time in response to operator manipulation of the headlamp switch so as to move the headlamp carrier toward the first mechanical stop to expose the headlamp if the headlamp switch is in the ON position and toward the second mechanical stop to conceal the headlamp if the headlamp switch is in the OFF position, the predetermined period of time being sufficient in duration to produce motor rotation that increases the motor counter-EMF substantially above zero; and

thereafter

continuing the motor energization in a series of pulses for producing further movement of the headlamp carrier;

sensing a motor counter-EMF related voltage as an indication of motor rotation and generating a stall signal when the motor counter-EMF falls substantially to zero indicating that the motor speed has fallen substantially to zero, whereby engagement of the carrier with the stops is sensed without the use of a headlamp switch to sense such engagement;

interrupting energization of the motor in response to the generation of a stall signal thereby to prevent further energization of the motor after the carrier has been moved into engagement with the mechanical stop; and

interrupting energization of the motor to prevent further movement of the headlamp carrier if the motor is energized for moving the headlamp carrier toward the second mechanical stop to conceal the headlamp while the headlamp switch is in the ON position.

7. A motor vehicle lighting system comprising in combination:

a headlamp, an operator manipulated headlamp switch, movable concealment means, a source of direct voltage, an electric motor connected to said concealment means and adapted to be energized with said source for moving the concealment means into engagement with a mechanical stop to fully expose the headlamp, and motor control means including oscillator means for generating a series of pulses in response to operator manipulation of headlamp switch, run means operative to energize said motor with said source in accordance with the pulses generated by said oscillator means for moving the concealment means toward the mechanical stop, voltage responsive means for sensing a motor counter-EMF related voltage as an indication of motor rotation and for generating a stall signal when the motor counter-EMF falls substantially to zero indicating that the motor speed has fallen substantially to zero, whereby engagement of the concealment means with the stop is sensed without the use of a limit switch to sense such engagement, stop means for inhibiting further operation of said run means in response to the generation of a stall signal by said voltage responsive means thereby to interrupt motor energization after the motor moves the concealment means into engagement with said mechanical stop, and start means initiated in response to operator manipulation of said headlamp switch for energizing said motor independent of said run means for a period of time sufficient in duration to produce motor rotation for increasing the motor counter-EMF substantially above zero, whereafter motor energization is controlled by said run means, said voltage responsive means and said stop means.

8. A motor vehicle lighting system according to claim 7 wherein said motor control means includes:

means for inhibiting operation of said run means a predefined period of time after the operator manipulation of the headlamp switch, thereby to prevent continued motor energization in the event that the motor becomes disconnected from the concealment means.

9. A motor vehicle lighting system comprising in combination:

movable concealment means for a headlamp, a source of direct voltage, an electric motor adapted to be energized with said source for moving the concealment means into engagement with first or second mechanical stops to fully expose or conceal the headlamp, a headlamp switch operator manipulatable to an ON position to energize the headlamp or an OFF position to de-energize the headlamp, and motor control means including oscillator means for generating a series of pulses in response to operator manipulation of the headlamp switch, run means operative to energize said motor with said source in accordance with the pulses generated by said oscillator means for moving the concealment means toward the first mechanical stop to expose the headlamp if the headlamp switch is in the ON position and toward the second mechanical stop if the headlamp switch is in the OFF position, voltage responsive means for sensing a motor counter-EMF related voltage as an indication of motor rotation and for generating a stall signal when the motor counter-EMF falls substantially to zero indicating that the motor'"'"'s speed has fallen substantially to zero, whereby engagement of the concealment means with the stops is sensed without the use of a limit switch to sense such an engagement, stop means for inhibiting further operation of said run means in response to generation of a stall signal by said voltage responsive means thereby to interrupt motor energization after the motor moves the concealment means into engagement with said stops, start means initiated in response to operator manipulation of the headlamp switch for energizing the motor independent of said run means for a period of time sufficient in duration to produce motor rotation for increasing the motor counter-EMF substantially above zero whereafter motor energization is controlled by said run means, said voltage responsive means and said stop means, and means for interrupting energization of said motor to prevent further movement of said concealment means if the motor is energized for moving the concealment means toward the second mechanical stop to conceal the headlamp while the headlamp switch is in the ON position.

10. An actuator system comprising in combination:

operator manipulated switching means, movable device means, a source of direct voltage, an electric motor connected to said movable device means and adapted to be energized with said source for moving the device means into engagement with a mechanical stop, and motor control means including oscillator means for generating a series of pulses in response to operator manipulation of the switching means, run means operative to energize said motor with said source in accordance with the pulses generated by said oscillator means for moving the device means toward the mechanical stop, voltage responsive means for sensing a motor counter-EMF related voltage as an indication of motor rotation and for generating a stall signal when the motor counter-EMF falls substantially to zero indicating that the motor speed has fallen substantially to zero, whereby engagement of the device means with the stop is sensed without the use of a limit switch to sense such engagement, stop means for inhibiting further operation of said run means in response to the generation of a stall signal by said voltage responsive means thereby to interrupt motor energization after the motor moves the device means into engagement with said mechanical stop, and start means initiated in response to operator manipulation of said switching means for energizing said motor independent of said run means for a period of time sufficient in duration to produce motor rotation for increasing the motor counter-EMF substantially above zero, whereafter motor energization is controlled by said run means, said voltage responsive means and said stop means.