| 摘要 |
<p>A winch for hoisting loads on building sites has a winding drum (18) with an internal free-wheel mounted on a shaft (17). The shaft is driven by a gear wheel (14) through a layshaft (13) and gears from the pulley (3) which is driven from a motor. When lifting a load the layshaft is driven through the gears (5', 12) which are engaged by the clutch (5). During descent, the clutch is disengaged and a second clutch (2) is engaged which drives the layshaft (13) by means of chain and so reverses its direction. The winch motor is then driven from the pulley (3) and acts as a brake.</p> |
