Work-clamp pallet for machine tool

A work clamp pallet for a machine tool comprising:

• a. a base block having means on a lower surface for attachment to a bed of a machine tool;
• b. a plurality of hydraulically activated work clamping devices attached to the base block such that a plurality of workpieces may be mounted on the base block;
• c. hydraulic fluid conduit means attached to the base block and interconnecting the work clamping devices;
• d. a hydraulic fluid pressure source;
• e. self-sealing coupling means for attaching the hydraulic fluid pressure source to the fluid conduit means;
• and,
• f. a shut-off valve attached to the base block and interposed between the self-sealing coupling means and the fluid conduit means, the valve having:
• i. a valve core element biased against a valve seat to close the valve and prevent decline of the hydraulic fluid pressure in the work clamping devices and the fluid conduit means;
• ii. valve operating means to move the valve core element against the spring bias away from the valve seat to open the valve and permit fluid to flow through the self-sealing coupling;
• and,
• iii. auxiliary valve means located between the valve seat and the self-sealing coupling to release the hydraulic fluid pressure in the shut-off valve.