Method and means for installing blind fasteners

Setting means for installing a blind fastener comprised of a headed rivet sleeve and a headed pin inserted therewithin;

• the head of the sleeve being adapted to engage the top side of the work being fastened, the head of the pin engaging the end of the sleeve remote from the sleeve head, the sleeve end and pin head being beyond the blind side of the work, and the pin having a tail extending beyond the sleeve head which means comprises:
• a support housing;
• a chuck assembly slidably mounted within said support housing and having means to grasp the tail of said pin;
• a collet slidably mounted within said support housing and protruding beyond said support housing, said collet having a forward portion to engage a sleeve head;
• a first cam surface on said support housing and a second cam surface on said collet, said cam surfaces being arranged to engage one another;
• a cutting edge on said collet adjacent said forward portion;
• and yieldable means associated with said collet to prevent initial movement of said cutting edge;
• whereby when the load forces exerted by movement of the chuck assembly are sufficient to upset the blind fastener, continued movement of said chuck assembly will thereafter cause relative movement and engagement between said cam surfaces to move said cutting edge into said pin to weaken same adjacent the sleeve head, further movement of said chuck assembly causing said pin to break where so weakened.

A method for installing a blind fastener of the type comprising a headed rivet sleeve and a headed pin inserted there within, the head of the sleeve being adapted to engage the top side of work being fastened, the head of the pin engaging the end of the sleeve remote from the sleeve head, the sleeve end and pin head being beyond the blind side of the work, and the pin having a tail portion extending beyond the sleeve head, which method comprises the steps of:

• a. providing a tool comprised of a collet having a cutting edge and means to apply a pulling force on said tail portion of said pin to bulb said rivet sleeve to clamp the work between the bulb and the sleeve head;
• b. arranging said collet and cutting edge to weaken said tail portion at said sleeve head;
• c. providing yieldable means on said collet to prevent operation of said cutting edge during the clamping of the work between said bulb and said sleeve head, said yieldable means enabling operation of said cutting edge to weaken said tail portion in response to a pulling force on said tail portion greater than is required to bulb said sleeve;
• d. initially pulling said tail portion of said pin sufficient only to bulb said rivet sleeve to clamp the work between said bulb and said sleeve head;
• e. thereafter further pulling said tail portion to cause said yieldable means to be overcome whereby to enable operation of said cutting edge to weaken said tail portion at said sleeve head;
• and
• f. further pulling said tail portion to cause said tail portion to break where so weakened.