| 摘要 |
An electrically actuated brake may be operated remotely, e.g. attached to a battery powered lightweight rail maintenance vehicle, or a trailer towed by such a vehicle. It comprises an electrically operated actuator (34, Fig. 4 ) having a control system (36, Fig. 4 ) responsive to both
(i) an electrical signal variable between substantially two discrete states (e.g. "on" and "off") and
(ii) a continuously variable electrical signal;
the control system controlling the actuator in response to the signal variable between the two discrete states to move the brake between a fully applied and a fully released condition; the control system being further operative to control the actuator in response to the continuously variable signal to move the brake so as to provide a continuously variable braking force/torque. Both signals (i) and (ii) are applied to the control system through a common control line 76. Brake shoes 22 are moved by the actuator via a mechanical linkage 26, against a resilient bias provided by tension springs (72, Fig. 4 ). |
