| 摘要 |
<p>The device comprises an adjustable friction system for the lamp descent, wherein the suspension wire winding drum (21) is free to rotate in the wire return or rewinding direction, while its rotation, around a central stationary axis (20A-20B) is braked and regulated by the friction system in the direction of wire unwinding and therefore of lamp descent, said rotation being controlled by a ratchet wheel (25) of special structure. Thus it is obtained an up-and-down pulley device having a silent, precise and adjustable operation and a compact, sturdy structure comprising a limited number of elements. </p> |
