| 摘要 |
<p>A jib crane (J) is provided with a jib (21), first and second fixed pulleys (22, 23) attached to the jib (21), first and second moving pulleys (32, 42), a wire rope (25) secured at the distal end to the jib (21) and wound about the first and second fixed pulleys (22, 23) and the first and second moving pulleys (32, 42), and a winch (26) capable of taking up and letting out the wire rope (25). The first and second moving pulleys (32, 42) are provided with a first moving pulley (32) installed in a first moving pulley block (30) equipped with a hook, and with a second moving pulley (42) installed in a second sheave block (40) releasably linked to the first moving pulley block (30) through a linking mechanism (24).</p> |
