Mechanism for and method of shifting cam mechanisms in a press for pressing workpieces with depressed portions

A method of shifting cam mechanism in a press, comprising the steps:

• lowering a top form toward a bottom form;
• lowering a pin toward a first cam follower through a pad in response to the lowering movement of said top form to move said cam follower while compressing a resilient compressible support between said forms:
• moving a second cam follower having a die in a direction toward a workpiece in response to the lowering movement of said first cam follower;
• moving a third cam follower having a punch in a direction toward the workpiece through a fixed cam on said top form in response to the lowering movement of the latter;
• returning said third cam follower to an initial position thereof away from the workpiece in response to upward movement of said top form away from said bottom form while returning said support to an initial position thereof;
• and
• returning said pad, said pin, said first and second cam folowers to initial positions thereof in response to the upward movement of said top form slightly after said third cam follower has started returning to its initial position.

In combination,

• a press having a top form and a bottom form movable vertically towards and away from each other;
• a die between said forms for engaging a workpiece;
• a punch for working an engaged workpiece on said die;
• a first cam mechanism between said forms for moving said die between a working position and a retracted position, said mechanism including a vertically movable pad below and spaced from said top form, a pin extending vertically from said pad, a first cam follower below said pin for vertical movement therewith, a second cam follower mounted on said bottom form in abutment with said first cam follower and mounting said die thereon, a first spring biasing said first cam follower towards said pin and a second spring biasing said secnd cam follower against said first cam follower, a lost-motion connection betweeen said pad and said top form, and a resilient compressible support between said pad and said top form, said support being compressible upon movement of said forms towards each other to permit abutment of said top form against said pad while actuating said cam mechanism to move said die to said working position and after an initial movement of said forms away from each other to permit said cam mechanism to move said die a predetermined distance to said retracted position;
• and
• a second cam mechanism between said forms for moving said punch between a working position and a retracted position, said second cam mechanism including a fixed cam mounted on said top form, a third follower in abutment with said cam and secured to said punch for moving said punch to said working position thereof in rsponse to said forms moving towards each other and a third spring for moving said third cam follower to return said punch to said retracted position thereof in response to said forms moving away from each other.