| 摘要 |
<p>The motorised (10) cable traverses idling pulley wheels (2-6) at changes of direction and is used to drive side-hung gates (13, 14). The cable (1) is sited parallel with and close to the ground and attaches (11,12) to the free end of both gates (13,14), the cable extension occasioned by gate movement being accommodated by springs or extensible cables. Alternatively, the variation in cable length may be taken up by winding and unwinding drums (9) of which the effective diameter varies, and the gates (13,14) may be locked by an electro-magnetic brake acting on the motor (10) or by irreversible endless screw reduction gearing.</p> |
