摘要 |
The invention relates to a manual hydraulic operating vise, said vise comprising a stationary jaw with a cylindrical center assembly formed in the body of the stationary jaw. A movable jaw being firmly connected to a main piston in the center assembly by a movable rod. A handwheel used to operate a control valve to seat or unseat on a boost piston in an inner liner inside of the center assembly. Several internal oil passages are provided therein for free oil flow around the main piston when the control valve is unseated, so that the movable jaw can be positioned manually with least resistance, thus greatly reduce the time for positioning. When the control valve is seated further turning handwheel will operate the movable jaw backward hydraulically to clamp the workpiece with a greater force which is the multiplication of force input on the handwheel because hydraulic and mechanical advantage of the structure.
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