| 摘要 |
Disclosed herein is a mechanical screw jack comprising: a housing; a mechanical jack stroke limiting nut connected to the housing, the nut having a nut wall, the wall defining an interior female threaded surface and an interior screw travel limiting surface located adjacent to the interior female threaded surface; and a mechanical jack screw having an externally threaded male surface for threadably engaging the interior female threaded surface of the mechanical jack stroke limiting nut and a disruption; wherein the unthreaded screw travel limiting surface is capable of interferingly engaging at least a portion of the disruption to prevent over travel of the threaded screw. A method of limiting screw travel in a mechanical screw jack is also disclosed. Advantageously, screw travel is limited such that a user can over torque the screw, such that the screw can travel with respect to the nut without damaging the threaded portion of the nut. The invention increases mechanical screw jack life and reduces the likelihood of separation of such mechanical jacks into their component parts during repeated and vigorous use. The invention further reduces, or substantially eliminates the likelihood of a user experiencing any residual torque effect which can cause a screw jack to lock up during repeated use.
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