| 摘要 |
An assembly for ground level installation and servicing of one or more pole-mounted light sources includes a support rack having guide sheaves which ride the pole in response to operation of a hoist cable and pulley arrangement. To slow the fall of the rack in the event of hoist cable failure during raising or lowering, the guide sheaves are urged against the pole by springs which remain in compression independently of hoist cable tension. The rack is latched at the pole top independently of the hoist cable and is releasable at ground level by actuation of a latch line. Light sources are mounted on the rack at a higher elevation than the guide sheaves to cause the sheaves, rather than the sources, to absorb substantially all impact if the rack falls.
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