| 摘要 |
An above-ground gravity return hose retractor, which is particularly useful in service stations for supplying air and water, encloses the hoses and the retraction mechanism within a cabinet. A block and tackle pulley arrangement, including a vertically movable pulley sheave supported by the hose, is located within the cabinet. The movable pulley sheave has a non-linear, variable weight attached to it in the form of an elongated chain having a first segment of small, relatively lightweight links attached through a limit spring to the sheave. These lightweight links then are attached to an additional segment of chain having intermediate weight links, with the lowermost portion of the chain comprising larger, heavier links. The final link in the chain is attached to the bottom of the cabinet. The full length of the chain is reached just prior to the final extension of the hose. The limit spring then provides a significant increase in resistance to further withdrawal of the hose when the chain is fully extended. Upon release, the variable weight chain exerts the greatest pulling force upon initial retraction of the hose, and the retraction pulling force decreases non-linearly to its lowest value when the hose is nearly fully retracted.
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