Title:
OVERLOAD CONTROLLER OF ELECTRIC SHUTTER
Document Type and Number:
Japanese Patent JPH1181837
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To prevent burning of a drive circuit by changing a duty factor when it is judged that a motor is in an overload condition until a condition amount drops below a specified value and comparing the maximum value of a specific condition amount with the specified value when the required time exceeds a specified time to stop a shutter by closing and driving it or drive it by returning reversely. SOLUTION: When a shutter 2 provided on a cargo-carrying platform of a van type truck is opened and closed by a motor 3 and an overload judging means 8 judges that the motor 3 is in an overload condition, a change means 9 decreases a duty factor for pulse width modulation at the time little by little until its average current drops below a specified value, and a calculating means 10 divides the average current by a new duty factor, multiplies the value by a compensation value, and calculates the maximum value of a current which flows in a drive circuit 6 when the required time exceeds a specified time. A drive indication judging means 11 instructs reverse return of the shutter 2 when the calculated maximum value is below the specified value and instructs its drive for closing and stopping when the maximum value exceeds the specified value.
Inventors:
ODAWARA TATSUO
Application Number:
JP24009797A
Publication Date:
March 26, 1999
Filing Date:
September 05, 1997
Export Citation:
Assignee:
SANWA SEIKI MFG CO LTD
International Classes:
E06B9/56; B60J5/14; E06B9/68; E06B9/80; E06B9/82; H02P3/06; (IPC1-7): E06B9/80; B60J5/14; E06B9/56; H02P3/06
Attorney, Agent or Firm:
Yukio Fujii