| 摘要 |
A stressing jack is of light weight because limiting means (19) are provided to reduce the axial tension generated in the rearward end of the jack casing (1) at or towards the limit of the rearward movement of the jack pulling cylinder (8). Preferably the limiting means is a safety pressure limiting shuttle valve (19) having a plunger (22). Because of the limiting means the outer cylinder wall can be of low thickness which saves weight and creates stability.
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