Detector for electromagnetic brake

摘要

A detector for an electromagnetic brake, for example used in an elevator system, that, by quantitative judgment, determines whether the brake force of the electromagnetic brake is appropriate. Load cells for detecting the recovery forces of brake springs are arranged between brake springs, which energize brake arms with brake shooes installed on them toward the side of brake wheel, and spring sheets, which hold brake springs in a compressive deformed state, and, at the same time, judgment part judges whether the brake force of electromagnetic brake 4 is outside a prescribed normal range based on the outputs of load cells. If the brake force of electromagnetic brake is outside the normal range, judgment part sends a signal, for example to a monitoring center.

主权项

1. A detector for an electromagnetic brake, while a brake force is generated by pressing a brake piece on a member for braking with the recovery force based on elastic deformation of a brake spring, said brake piece is driven away from the member for braking against the recovery force of said brake spring by means of an electromagnetic attracting force caused by excitation of a solenoid so that the brake force is released; the detector comprising:
a load sensor that detects the recovery force of said brake spring; a judgment means that determines a condition of the electromagnetic brake based on the output of said load sensor; wherein said judgment means determines whether the brake force of the electromagnetic brake is lower than a prescribed normal judgment lower limit or higher than a prescribed normal judgment upper limit based on the output of said load sensor, and, if the brake force of the electromagnetic brake is found to be lower than a prescribed normal judgment lower limit or higher than a prescribed normal judgment upper limit, a detection signal is output to a monitoring center; and wherein said detection signal is either: a first detection signal sent to a monitoring center that the brake force of said electromagnetic brake is lower than said normal judgment lower limit and is higher than an operation stop value preset to be lower than said normal judgment lower limit, or if the brake force of said electromagnetic brake is higher than said acceptable upper limit, while operation of the elevator is continued, or a second detection signal sent to the monitoring center that the brake force of the electromagnetic brake is even lower than said operation stop preset value, said second detection signal indicating the state is output as said detection signal to the monitoring center, while operation of the elevator is turned off.