Patent ID: 9388714
Filing Date: 2016-07-12
CPC Classification: B21C,F01L,Y10T

Claim Text:
1. A method of cold-forming a ball plunger blank comprising the steps of: providing a slug having first and second ends, the first end configured to receive a check valve assembly, the second end configured to engage a rocker arm; backward extruding the slug at the first end to form a bore having an axial length and a first diameter that is defined by a wall, and that extends a length to a terminal end at the slug; forming a generally ball-shaped outer surface at the second end of the slug; upsetting at least a portion of the wall to form a counterbore having a second diameter and a shoulder wherein the second diameter is greater than the first diameter and wherein the shoulder only partially closes the bore and defines a ball seat surface to final dimensions wherein the bore remains open along the axial length to the counterbore through an opening defined by the shoulder subsequent to the upsetting; simultaneously with the upsetting, forming a closed hemispherical surface at the generally ball-shaped outer surface at the second end of the slug to near final dimensions; and forming the closed hemispherical surface to final dimensions.