| 摘要 |
A pulley is mounted in a surrounding hanging housing, open at the base end thereof and a cable is entrained over the pulley. The cable is provided with a pull means at one end the other end carries a load. Near each end of the cable are tripping brackets engaging a lever mechanism pivoted from the lower portion of the housing. The lever mechanism engages a pivoted tooth pawl. When the lever is tilted one way the pawl engages the load side of the cable to hold it in place when there is no pull on the other side. When the tripping bracket on the load side of the cable reaches the lower edge of the lever it tilts the right side of the lever upwardly which in turn engages a transverse pin on the pawl to move the end of the pawl teeth away from the load side cable and allow the load to descend. When the bracket on the pull side of the cable has risen to the lower left edge of the lever, the lever is tilted towards the load side allowing the pawl to engage the load side of the cable. This mechanism provides a means for safely lifting loads manually to heights above the user and automatically locking or holding the load in place. It has the capability to automatically release the locking mechanism to allow the load to descend towards the user and again allow the locking pawl to engage the load side of the cable.
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