Hydropneumatic blind riveter with automatic mandrel catcher

A blind riveter comprising:

• a housing forming an air chamber and a liquid-filled hydraulic chamber adjacent thereto;
• a head on said housing having a tip and forming a liquid--filled working chamber communicating with said hydraulic chamber;
• a working piston in said working chamber and carrying a chuck for grasping a mandrel of a blind rivet, said head and chuck forming a passage having a front end opening at said tip and a rear end, said piston being displaceable in said working chamber between a ready position juxtaposed with said tip and wherein a mandrel of a blind rivet can be fitted into said passage at said chuck with said rivet engaged backwardly against said tip and an actuated position spaced from said tip and wherein said chuck is retracted;
• a generally closed mandrel-catching compartment on said head, said other end of said passage opening into said compartment;
• an air piston in said air chamber;
• a hydraulic piston carried on said air piston and displaceable in said hydraulic chamber between an advanced position pressurizing said hydraulic chamber and corresponding to a front position of said air piston and a retracted position corresponding to a rear position of said air piston;
• means for pressurizing said air chamber and thereby moving said air and hydraulic pistons into the respective front and advanced positions for pressurizing said working chamber and displacing said chuck from said ready to said actuated position, whereby on displacement of said chuck from said ready to said actuated position the mandrel is pulled off the rivet at said tip
• a nozzle directed in said passage toward said other end;
• and
• valve means connected between said air chamber and said passage for feeding air under pressure from said air chamber to said nozzle after displacement of said chuck from said actuated into said ready position and for thereby simultaneously sucking the pulled-off mandrel from said chuck back along said passage into said compartment, said chuck including an inner mandrel tube extending back toward said other end and having an end forming part of said nozzle, said air piston subdividing said air chamber into a front air chamber and a rear air chamber and is displaceable between a front position of maximum volume of said rear air chamber and minimum volume of said front air chamber and a rear position of minimum volume of said rear air chamber and maximum volume of said front air chamber, said air piston having a front face exposed in said front air chamber and from which said hydraulic piston projects and a rear face exposed in said rear air chamber and of generally the same effective surface area as said front face, said chuck carrying a second air piston distinct from the first-mentioned air piston and said head is formed around said second air piston with a second air chamber distinct from the first-mentioned air chamber and permanently communicating with said front air chamber, said chuck including a puller tube fixed to said second air piston and to said working piston, said valve means being connected between said second air chamber and said rear air chamber and connecting same together on displacement of said chuck from said actuated to said ready position, said second air piston being displaceable through an intermediate position corresponding to an intermediate position of said chuck between said chuck and ready positions, said second air chamber being connected to said nozzle between said intermediate position and said ready position of said chuck.