Adjustable pierce unit

Claim 1

A FLUID ACTUATED PIERCING UNIT COMPRISING A BODY HAVING A CYLINDER BORE AND A FLUID CONNECTION THROUGH WHICH FLUID IS SUPPLIED TO ONE END OF SAID BORE, THE OTHER END OF SAID BORE BEING PROVIDED WITH A VENTING PORT, A PISTON RECIPROCABLE IN SAID BORE AND PROVIDED WITH A ROD WHICH EXTENDS FROM THE OTHER END OF SAID BORE, A BEARING CAP SECURED TO SAID BODY AT SAID OTHER END OF SAID BORE AND THROUGH WHICH SAID PISTON ROD EXTENDS, SAID PISTON ROD BEING AXIALLY SLIDABLY MOUNTED IN SAID CAP AND HAVING AN AXIAL GROOVE IN THE PERIPHERY THEREOF, A SOCKET IN THE OUTER END OF SAID PISTON ROD, A PUNCH HAVING ONE END REMOVABLY SECURED WITHIN SAID SOCKET AND PROJECTING THEREFROM FOR COOPERATION WITH A DIE MEMBER, A CUP-SHAPED CLAMPING SLEEVE REMOVABLY SECURED OVER SAID BEARING CAP, A WASHER AROUND SAID PISTON ROD AND CLAMPED BY AND BETWEEN SAID SLEEVE AND BEARING CAP AND HAVING AN INTEGRAL KEY EXTENDING INTO SAID GROOVE IN SAID PISTON ROD SO AS TO LOCK THE LATTER AND THE PUNCH CARRIED THEREBY AGAINST ROTATION, A STRIPPER SLIDABLY MOUNTED FOR LIMITED AXIAL MOVEMENT OF SAID SOCKET, AND A SPRING HOUSED WITHIN SAID STRIPPER AND BIASING IT TO AN EXTENDED POSITION RELATIVE TO SAID PUNCH SO AS TO CLAMP THE WORK AGAINST THE DIE PRIOR TO ENGAGEMENT OF THE PUNCH WITH THE WORK UPON ACTUATION OF SAID PIERCING UNIT IN RESPONSE TO THE SUPPLY OF FLUID UNDER PRESSURE TO SAID ONE END OF SAID CYLINDER BORE.