Fast-action multiple tapping machine

In combination with a press having a pair of platens movable through a predetermined distance in a predetermined direction between an outer position and an inner position, a tapping machine comprising:

• a base plate fixed to one of the platens;
• a spindle member extending along a spindle axis between the platens in the direction;
• a nut member threaded on the spindle member, one of the members being rotatable about the spindle axis on the base plate and the other member being fixed nonrotatably about the spindle axis on the other platen, whereby relative displacement of the platens rotates the one member in the base plate;
• an element displaceable on the base plate along an element axis but nonrotatably on the base plate about the element axis;
• an internal thread formed in the element;
• an externally threaded drive member in continuous-mesh engagement with the nut and meshing with the internal thread of the element;
• at least one tap holder generally fixed relative to the element axis in the element and rotatable in the element about a respective tap axis parallel to the element axis;
• respective drive teeth formed on the holder;
• external drive teeth formed on the drive member and meshing with the teeth of the holder;
• a tap fixed axially and rotationally in the holder and of a predetermined pitch;
• rotary transmission means operatively connected between the rotary one member and the drive member for synchronously rotating the holder and its tap at a predetermined tap rotation rate about the tap axis on rotation of the one member about the spindle axis;
• and
• axial-feed transmission means operatively connected between the rotary one member and the drive member for synchronously axially advancing the element with the tap and tap holder on displacement of the platens from the outer position to the inner position through a predetermined tap stroke equal to a fraction of the press stroke and at a rate such that the tap are rotated through substantially only one revolution while being advanced through a distance equal to the pitch.

In combination with a press having a pair of platens movable through a predetermined distance in a predetermined direction between an outer position and an inner position, a tapping machine comprising:

• a base plate fixed to one of the platens;
• a spindle member extending along a spindle axis between the platens in the direction;
• a nut member threaded on the spindle member, one of the members being rotatable about the spindle axis on the base plate and the other member being fixed nonrotatably about the spindle axis on the other platen, whereby relative displacement of the platens rotates the one member in the base plate;
• an element displaceable on the base plate along an element axis but nonrotatable on the base plate about the element axis;
• at least one tap holder generally fixed relative to the element axis in the element and rotatable in the element about a respective tap axis parallel to the element axis;
• a tap fixed axially and rotationally in the holder and of a predetermined pitch;
• a cam having an inclined camming surface engageable with the element;
• a spring urging the element axially back against the camming surface;
• an eccentric drive member having a surface bearing on the cam and in continuous-mesh engagement with the nut;
• rotary transmission means operatively connected between the rotary one member and the cam for synchronously rotating the holder and its tap at a predetermined tap rotation rate about the tap axis on rotation of the one member about the spindle axis;
• and
• axial-feed transmission means operatively connected between the rotary one member and the cam for synchronously axially advancing the element with the tap and tap holder on displacement of the platens from the outer position to the inner position through a predetermined tap stroke equal to a fraction of the press stroke and at a rate such that the tap are rotated through substantially only one revolution while being advanced through a distance equal to the pitch.