Westinghouse Electric Corporation

Charles W Maiden

Frederick O Johnson

Ernest F Conroy, Jr

Joachim E Wolf

John G Dorman

Andrew P Kruper

A transportation apparatus having improved brake control. The actual speed of the transportation apparatus is compared with a reference speed signal, and when the actual speed exceeds the reference speed a brake is applied to slow the transportation apparatus. Rather than simply applying the full torque of the brake abruptly, the present invention discloses an apparatus for pulse duration modulating the control signal for controlling the brake. The brake responds to the average of the pulse duration modulated control signal such that braking torque is applied gradually and essentially linearly. The device can also be used in an acceleration situation to provide gradual acceleration of the transportation apparatus.

Conveyor brake control

An escalator having improved brake control, to limit the rate of deceleration immediately following a stop command, and to quickly cause the actual speed of the escalator to closely follow a linearly declining speed ramp of a speed pattern signal. The signal controlling the brake is pulse duration modulated such that the brake responds to the average pulse duration, and braking torque is applied gradually and essentially linearly. The reference speed pattern has a substantially constant portion and a declining ramp portion. To limit the initial deceleration, the constant portion of the speed pattern is controlled to be a function of the actual speed signal, and the declining ramp portion of the reference signal is controlled to start when the actual speed is equal to the constant portion of the reference speed signal.

Growing community of inventors

Brentwood, PA, United States of America

Charles W Maiden