Workpiece replacement device for machine tools

摘要

The invention relates to a workpiece exchanging or replacement device for machine tools and aims to improve the useful effect of the workpiece exchanging device. The workpieces are positioned and arranged and clamped on or removed from each workpiece clamping pallet at a workpiece replacement station that is provided externally of the machine tool, in order subsequently to be conveyed from a transfer bed to a workpiece clamping pallet exchanging station where they are pushed onto a workpiece table of the machine tool, arranged and positioned and are clamped thereon ready for machining. The workpiece clamping pallet comprises a base plate in which hydraulic cylinders are fully inserted. Each cylinder comprises a vertically movable piston below the head surface of the base plate. The piston may carry a clamping member which is detachably secured thereto in order thereby to transmit a clamping force from the piston to the clamping member. The base plate also comprises an oil circulation system in order to apply hydraulic pressure to each of the cylinders. Furthermore, a leakproof and liquid tight, reversible shut-off valve is provided to maintain the oil pressure in the hydraulic cylinder and in the oil circulation system of the threaded plate, in order to permit the oil circulation system to be closed so that it is also possible to transfer the workpiece clamping pallet with the oil hose separated and to continue with the machining work without having to fill up with hydraulic oil. In order to guarantee safety in the rare occurrence of oil leaks, means preventing a drop in oil pressure and means detecting a drop in oil pressure are also provided. <IMAGE>