Pneumatic rivet setting guns

Claim 1

IN A RIVET SETTING TOOL HAVING JAWS WHICH ARE POWER ACTUATED REARWARDLY TO GRIP, TENSION AND SEVER A MANDRIL STEM PORTION OF A RIVET ASSEMBLY AND WHICH ARE SPRING RETURNED TO THEIR FORWARD POSITION WHEREAT THE JAWS ARE ADAPTED TO RELEASE THE SEVERED MANDRIL STEM PORTION, THE COMBINATION OF: A PRESSURE CHAMBER WITHIN THE FORWARD END OF WHICH SAID JAWS ARE OPERATIVLEY MOVABLE ALONG A PATH IN AXIAL ALINEMENT WITH A MANDRIL STEM RECEIVING THROAT APERTURED TO FIT CLOSELY AROUND THE STEM OF A MANDRIL WHEN INSERTED BETWEEN THE JAWS; A FLEXIBLE RESILIENT DIAPHRAGM, THE PERIPHERAL EDGE OF WHICH IS SECURED TO FORM A SEAL AT THE REARWARD END OF THE PRESSURE CHAMBER; AN ACTUATING ROD OPERATIVELY CONNECTING THE CENTER PORTION OF THE DIAPHRAGM WITH SAID JAWS; SPRING MEANS YIELDABLY URGING THE ROD AND DIAPHRAGM CENTER FORWARDLY TO LOCATE THE JAWS AT THEIR FORWARD MANDRIL-RELEASING POSITION; AND A SOURCE OF PNEUMATIC PRESSURE INCLUDING A SHIFTABLE AIR VALVE FOR PORTING COMPRESSED AIR INTO THE PRESSURE CHAMBER, SAID PRESSURE WHEN FIRST PORTED INTO THE CHAMBER CAUSING THE RESILIENT MARGINAL PORTIONS OF THE DIAPHRAGM TO BECOME DILATED REARWARDLY BEYOND THE CENTER PORTION OF THE DIAPHRAGM, THEREBY ENLARGING THE VOLUME OF THE PRESSURE CHAMBER WHILE SAID CENTER PORTION IS IN ITS FORWARD POSITION, AND LATER CAUSING SAID CENTER PORTION AND INTERCONNECTED JAWS TO BE ACTUATED REARWARDLY AGAINST THE FORCE OF SAID SPRING MEANS.