Orbital tool assembly for forming rivet heads

An orbital tool assembly for forming rivet heads comprising a housing adapted for an attachment to a driven member rotatable upon a first axis;

• said housing having a bore extending along a second axis inclined at an acute angle to said first axis;
• an elongated equalizing head having a longitudinal axis coincident with said second axis nested and retained within said housing;
• bearing means interposed between said head and housing for journalling said housing for rotation about said first axis relative to said head;
• said head having an axial bore defining a fluid pressure chamber open at one end;
• a cylindrical driver coaxial with and mounted upon said head projecting from said housing and having a plurality of longitudinal bores parallel to said second axis and communicating with said pressure chamber;
• a longitudinally reciprocal peening tool holder having an elongated bore movably mounted in each of said driver bores;
• each holder having a piston movable in said driver head bore and normally biased outward by pressurized fluid filling said head and driver bores on one side of said piston;
• an elongated peening tool mounted within each peening tool holder, at its outer end having a transverse rivet working surface, adapted for registry and operative engagement with an unheaded rivet projecting through a pair of parts upon a support to be secured together;
• an elongated anti-rotation arm extending at right angles to said driver and at one end mounted upon and secured thereto;
• and a bracket means upon a support retainingly engaging said arm at its opposite end against rotation, said arm being free for rocking movements in a plane passing through said axes;
• continuous rotation of said housing oscillating said head and peening tools in said plane over the ends of said rivets forming heads thereon.