| 摘要 |
A carriage lock selectively enables and prevents a mobile carriage from moving along rails embedded in a building floor. The mobile carriage includes a shaft on which are rotatably mounted a driver sprocket, a hub, and a handwheel. The hub mates with the driver sprocket. A chain and sprocket mechanism connects the driver sprocket with the carriage wheels such that rotation of the handwheel and hub causes the carriage to move along the rails. A locking knob is loosely captured between the hub and handwheel for being manually rotated through a predetermined angle relative to the hub and handwheel. A pin is translatable within the hub parallel to the shaft longitudinal axis. The pin has a head that is received within a selected one of two angularly spaced depressions in a cam formed on the locking knob. The depressions are also spaced apart in the direction of the shaft longitudinal axis. By rotating the locking knob through the predetermined angle to first and second positions, the cam translates the pin in the hub between respective first and second positions. In the first position, the pin engages a lock plate held stationarily to the shaft to thereby prevent rotation of the hub and handwheel and thus prevent carriage movement. Rotating the locking knob to the second position thereof translates the pin to disengage from the lock plate and thereby enables the hub and handwheel to be rotated to move the carriage.
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