| 摘要 |
A telescopic beam for use in an inclined hoist has five telescopic members. An actuator comprising a motorized winch and a block and tackle arrangement is provided for extending the telescopic members relative to one another. The block and tackle arrangement includes a cable which passes several times around sets of rollers positioned at the adjacent ends of first and second of the telescopic members. A lock is provided for fixing the positions of the first and second telescopic members. To relieve the operator of the need for controlling several actuators, the single actuator is used to control the extension of all the telescopic members, and to control the angle of inclination of the last telescopic member relative to the penultimate telescopic member. For this purpose, the cable is passed from the second telescopic member to the far end of the penultimate telescopic member, and then to the adjacent end of the last telescopic member where it is secured.
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