Circuit for preventing the erroneous operation of a motor control device for lifting and lowering a power window

• US 4,746,845 A
• Filed: 10/16/1986
• Issued: 05/24/1988
• Est. Priority Date: 07/30/1984
• Status: Expired due to Term

• Current Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Kondo, Shiro, Mizuta, Ken
• Primary Examiner(s): Ro, Bentsu
• Application Number:
  US06/920,898
• Time in Patent Office: 586 Days
• Field of Search: 49/26, 49/28, 318/256, 318/264, 318/265, 318/266, 318/267, 318/282, 318/286, 318/319, 318/450, 318/466, 318/468, 318/285, 318/434, 318/452, 318/469, 318/470
• US Class Current: 318/286
• CPC Class Codes: H02H 7/0851 for motors actuating a movable member between two end positions, e.g. detecting an end position or obstruction by overload signal

Abstract

An automatic window regulator for automobiles includes a drive motor for lifting and lowering the window glass, and a detector for detecting when there is a foreign object jammed between the window glass as it is lifted or lowered and a window frame. The detector includes sensor means for measuring motor characteristic values of the drive motor and comparator means for comparing a first motor characteristic value measured by the sensor means with a second motor characteristic value measured by the sensor means a prescribed period of time prior to the first motor characteristic value and for generating a detected signal indicative of the jammed foreign object when any difference between the compared first and second motor characteristic values is greater than a predetermined range.

Claims

1. A circuit for preventing the erroneous operation of a motor control device for lifting and lowering a power window having a drive motor for lifting and lowering the window glass, means for detecting when any foreign matter is caught between the window glass and a window frame when the window glass is lifted and lowered, said detecting means including sensor means for measuring a current characteristic value of said drive motor based on the load torque relative to supplied current and comparator means for comparing the present motor current characteristic value measured by said sensor means and a motor current characteristic value measured a predetermined of time before said present motor current characteristic value and providing a foreign matter detection signal if a difference value as the result of the comparison is greater than a predetermined range, and means for preventing the output of said foreign matter detection signal for a predetermined of time after the operation of an actuation switch for starting said drive motor.

2. In a device for controlling a motor for lifting and lowering a window glass automatically having means for detecting when any foreign matter is caught between the window glass and a window frame when the window glass is lifted,

the improvement wherein said detector means includes a sensor for measuring a real-time first characteristic value of said motor based on an electric current supplied to said motor and for generating a first characteristic value signal, delay circuit means for generating a second characteristic value signal based upon said first characteristic value signal delayed by a predetermined time delay, starting condition cancelling means for cancelling said first characteristic value signal for a predetermined period of time associated with a starting condition when said motor is actuated, and comparator means for comparing said second characteristic value signal with said first characteristic value signal processed through said starting condition cancelling means and for generating a foreign matter signal if said first and second characteristic value signals have therebetween a difference which is greater than a predetermined range, whereby said comparator means is prevented from generating said foreign matter signal by said starting condition cancelling means for said predetermined period of time associated with said starting condition of said motor.

3. A device according to claim 2, wherein said motor characteristic value is a voltage value developed across said drive motor.

4. A device according to claim 2, including a latching circuit for keeping said motor energized in response to a signal from a switch and for releasing said motor from energization in response to the foreign matter signal from said comparator means.

5. A device according to claim 4, including a reversing circuit responsive to the foreign matter signal from said comparator means for enabling said latching circuit to reverse said motor.