Circuit arrangement for power windows

• US 4,347,465 A
• Filed: 07/07/1980
• Issued: 08/31/1982
• Est. Priority Date: 07/04/1979
• Status: Expired due to Term

• Current Assignee: ITT Industries (ITT, Inc.)
• Original Assignee: ITT Industries (ITT, Inc.)
• Inventors: Prohaska, Hans, Goertler, Horst, Rachner, Horst, Muller, Hans, Hetzel, Friedrich, Spieth, Wolfgang, Knobloch, Uwe
• Primary Examiner(s): Weldon, Ulysses
• Application Number:
  US06/166,585
• Time in Patent Office: 785 Days
• Field of Search: 318/445, 318/449, 318/450, 318/466, 318/469, 318/474, 318/476, 318/478, 318/266, 318/286, 318/447, 318/290, 318/283, 318/282, 318/264, 49/26, 49/28
• US Class Current: 318/266
• CPC Class Codes: E05F 15/40 Safety devices, e.g. detection of obstructions or end positions
• CPC Class Codes: E05F 15/41 Detection by monitoring transmitted force or torque E05F15/48 takes precedence; Safety couplings with activation dependent upon torque or force, e.g. slip couplings
• CPC Class Codes: E05Y 2400/554 sensing motor load
• CPC Class Codes: E05Y 2900/55 Windows
• 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
• CPC Class Codes: H02H 7/0854 responsive to rate of change of current, couple or speed, e.g. anti-kickback protection H02H7/0851 takes precedence

Abstract

A safety control circuit for electric motors of power windows of automotive vehicles and which differentiates between a tight fitting of the window pane and an obstacle blockage. The motor current is selectively detected to provide a signal representative of the instantaneous rather than static current values. The detected signal is compared to a reference signal. When the detected signal exceeds the reference signal by a given value or longer than a predetermined interval, which indicates that an obstacle blockage has occurred, the motor current is switched off or reversed.

Claims

1. A safety control circuit for the electric motor of a power window for automotive vehicles which senses the motor current and differentiates between a tight fitting of the window pane and an obstacle blockage, said control circuit comprising, in combination:

first means for selectively applying and reversing operating current to said motor wherein said first means applies said operating current to said motor in a selected one of two current directions to reverse the output motion direction of said motor and removes said operating current to stop said motor;

second means for detecting the operating current of said motor for providing a first output signal indicative thereof;

third means having an input coupled to said second means and being responsive to said first output signal for providing a second output signal indicative of the instantaneous value of said first output signal;

fourth means for providing a reference signal indicative of a predetermined instantaneous operating current level;

fifth means having a pair of inputs respectively coupled to said third and fourth means for comparing said reference signal to said second output signal and for providing a third output signal when the level of said second signal exceeds the level of said reference signal during a predetermined time period; and

,

a switching element coupled between said first means and said fifth means and being responsive to said third output signal to remove or reverse said operating current from said motor when the level of said second signal exceeds the level of said reference signal during said predetermined time period.