Guide pin assembly for metal forming dies and method

In a metal forming die having first and second die members which mutually converge and diverge to form metal parts, the improvement of a guide pin assembly, comprising:

• a guide pin body including:
• a first end portion operably attached to said first die member;
• a second end portion disposed generally opposite said first end portion, and received by said second die member;
• a medial portion disposed between said first and second end portions, having an exterior surface for precisely guiding the converging and diverging motion between said first and second die members;
• and
• a first retainer groove extending about said exterior surface at a location disposed generally adjacent to said second end portion of said guide pin body;
• a guide pin head member including:
• an exterior size that is greater than the outside size of said guide pin body, an interior size that is generally commensurate with the outside size of said guide pin body, an outwardly facing end edge, and an inwardly facing end edge;
• a second retainer groove extending about a medial portion of said guide pin head member interior that is generally aligned with said first retainer groove in said guide pin body when said guide pin assembly is in an assembled condition;
• and
• a counterbore formed into said outwardly facing end edge of said guide pin head member, recessed into said interior of said guide pin head member and extending generally from said outwardly facing end edge to said second retainer groove, and defining at least one counterbore wall;
• a retainer having an inward portion thereof closely received and retained in said first retainer groove in said guide pin body, and an outward portion thereof protruding outwardly from said exterior surface of said guide pin body and being closely received and retained in said second retainer groove in said guide pin head member to fixedly mount said guide pin head member on said second end portion of said guide pin body and define an enlarged head portion of said guide pin assembly that serves to positively limit travel between the first and second die members;
• a guide pin head cap including:
• an outwardly oriented exterior face;
• an inwardly oriented interior face;
• and
• a support collar protruding inwardly from said interior face of said guide pin head cap, with an interior defining a socket in which said second end portion of said guide pin body is received, and an exterior surface which is closely received against said counterbore wall, such that said support collar is securely retained in said counterbore in said guide pin head member and said retainer is positively captured in said first retainer groove in said guide pin body and said second retainer groove in said guide pin head member, such that said guide pin head member is securely supported on said second end portion of said guide pin assembly during repeated, mutual convergence and divergence of said first and second die members.

A method for making a guide pin assembly for metal forming dies of the type having first and second die members which mutually converge and diverge to form metal parts, comprising:

• forming a guide pin body having a first end portion configured for secure operable attachment with the first die member, a second end portion disposed generally opposite the first end portion for secure operable attachment with the second die member, and a medial portion disposed between the first and second end portions, having an exterior surface for precisely guiding the converging and diverging motion between the first and second die members;
• forming a first retainer groove in the guide pin body extending about the exterior surface at a location disposed generally adjacent to the second end portion of the guide pin body with a shape that opens outwardly;
• forming a guide pin head member with an exterior sidewall having an outside size that is greater than the outside size of the guide pin body, an interior sidewall with an inside size that is generally commensurate with the outside size of the guide pin body, an outwardly facing end edge and an inwardly facing end edge;
• forming a second retainer groove in the guide pin ring head extending about a portion of the interior sidewall with a shape that opens inwardly, and is aligned with the first retainer groove in the guide pin body when the guide pin assembly is in an assembled condition;
• forming a counterbore in the outwardly facing end edge of the guide pin head member that defines at least one counterbore wall;
• providing a retainer having an inward portion shaped for close reception in the first retainer groove in the guide pin body, and an outward portion which protrudes outwardly from the exterior surface of the guide pin body and is shaped for close reception in the second retainer groove in the guide pin head member;
• forming a guide pin head cap with an outwardly oriented exterior face, an inwardly oriented interior face, and a support collar protruding inwardly from the interior face of the guide pin head cap, having a free end edge, an interior side wall defining a socket shaped to closely receive therein the second end portion of the guide pin body, and an exterior sidewall shaped to be closely received against the at least one counterbore wall;
• positioning the inward portion of the retainer in the first retainer groove in the guide pin body;
• sliding the guide pin head member onto and over the guide pin body from the first end portion thereof until the guide pin head member contacts at least a portion of the retainer mounted in the first retainer groove on the guide pin body;
• positioning the guide pin head cap over the outwardly facing end edge of the guide pin head member with at least a portion of the second end portion of the guide pin body received in the socket in the guide pin head cap, and at least a portion of the support collar of the guide pin head cap received in the counterbore in the guide pin head member;
• converging the guide pin head cap and the guide pin head member until at least a portion of the free end edge of the support ring on the guide pin head cap contacts at least a portion of the retainer mounted in the first retainer groove on the guide pin body;
• pressing the guide pin head cap and the guide pin head member together, causing engagement of the free end edge of the support ring against the retainer mounted in the first retainer groove on the guide pin body, and thereby shifting the outward portion of the retainer ring into the second retainer ring groove in the guide pin head member to fixedly mount the guide pin head member on the second end portion of the guide pin body and define an enlarged head portion of the guide pin assembly that serves to positively limit travel between the first and second die members;
• further pressing the guide pin head cap and the guide pin head member together until the second end portion of the guide pin body is fully received in the socket in the guide pin head cap, the support collar portion of the guide pin head cap is fully received in the counterbore in the guide pin head member, and the interior face of the guide pin head cap abuts with the facing end edge of the guide pin head member, whereby the retainer is positively captured in the first retainer groove in the guide pin body and the second retainer groove in the guide pin head member to rigidly support the guide pin head member on the second end portion of said guide pin body to withstand impact forces applied to the enlarged head portion of the guide pin assembly during repeated, mutual convergence and divergence of the first and second die members.