Die head with workpiece actuated release

A die head having replaceable threading dies comprising the combination of

• a die carrier comprising a generally cylindrical body having a hollow interior and a central axis, a plurality of projections extending axially from one end of said body and means defining a generally radially extending slot in each of said projections;
• a plurality of threading dies, each of said dies being radially slidable in one of said slots, said dies having inwardly facing thread forming surfaces defining a cavity to receive a workpiece;
• a cover plate on each of said projections;
• means in each of said threading dies for defining a cam slot opening generally away from said cover plate;
• a bearing flange axially adjustably mounted in the other end of said body, said bearing flange having a central opening therethrough;
• a cam bushing in said carrier having a plurality of cams enaging said slots in said threading dies, said cam bushing being axially shiftable relative to said body and having a reduced diameter portion extending into said opening in said bearing flange;
• means defining a central bore in said reduced diameter portion of said busing;
• a control pin in said central bore, said pin being axially adjustable and lockable against movement therein;
• a sensor bolt coupled to said control pin;
• a flange on said bolt;
• and
• stop cam means on said flange and facing said cavity, said stop cam means having a conical surface contactable by the workpiece for axially moving said flange, said sensor bolt, said control pin and said bushing when contacted and moved by the workpiece, thereby moving said threading dies radially outwardly.