Blind rivetting apparatus

Claim 1

A RIVETTING DEVICE COMPRISING MEANS DEFINING OPERATIVELY COUPLED PNEUMATIC AND HYDRAULIC CHAMBERS, SAID HYDRAULIC CHAMBER HAVING A HYDRAULIC MEDIUM THEREIN, PISTON MEANS EXTENDING BETWEEN SAID CHAMBERS AND DISPLACEABLE IN THE SAME, CONTROL MEANS FOR CONTROLLABLY ADMITTING A PNEUMATIC MEDIUM INTO AND TERMINATING THE SUPPLY OF SAID PNEUMATIC MEDIUM TO SAID PNEUMATIC CHAMBER, SAID PISTON MEANS BEING DISPLACED BY SAID PNEUMATIC MEDIUM FROM A FIRST TO A SECOND POSITION TO EXERT A FORCE ON SAID HYDRAULIC MEDIUM, SAID PNEUMATIC CHAMBER BEING PROVIDED ADJACENT SAID SECOND POSITION WITH AN OUTLET OPENING WHICH VENTS THE PNEUMATIC CHAMBER TO THE AMBIENT ATMOSPHERE, RIVET ENGAGING MEANS, AND ACTUATING MEANS COUPLED TO SAID HYDRAULIC CHAMBER AND TO SAID ENGAGING MEANS FOR OPERATING THE LATTER; SAID ACTUATING MEANS DEFINING A CHAMBER AND INCLUDING A PISTON DIVIDING THE LATTER SAID CHAMBER INTO FIRST AND SECOND SECTIONS, ONE OF SAID SECTIONS BEING COUPLED TO SAID HYDRAULIC CHAMBER TO RECEIVE HYDRAULIC MEDIUM THEREFROM WHEREBY SAID PISTON CAN BE DISPLACED BY SAID HYDRAULIC MEDIUM, AND A SPRING IN THE OTHER OF SAID SECTIONS AND OPPOSING MOVEMENT OF SAID PISTON BY THE HYDRAULIC MEDIUM, SAID PISTON BEING COUPLED TO AND OPERATING THE RIVET ENGAGING MEANS, SAID SPRING BEING OF A STRENGTH TO BE EFFECTIVE THROUGH SAID PISTON, UPON TERMINATION OF THE SUPPLY OF PNEUMATIC MEDIUM TO SAID PNEUMATIC CHAMBER, TO FORCE HYDRAULIC MEDIUM FROM SAID ONE SECTION INTO SAID HYDRAULIC CHAMBER TO RESTORE SAID PISTON MEANS TO SAID FIRST POSITION.