Spin forming method

摘要

A method of forming a groove in a pipe element by spin forming wherein the pipe element is pinched between an arbor revolving in an eccentric orbit of expanding diameter within the pipe element and an outer die which captures the pipe element. The pinching action causes a portion of the pipe element to move radially inwardly away from the die contrary to the direction of the motion of the arbor.

主权项

1. A method of forming a groove in an outer surface of a pipe element, said method comprising:
capturing an end of said pipe element in a die having first and second circumferential troughs arranged in spaced apart relation to one another; inserting an arbor within said pipe element, said arbor having a first circumferential rib aligned with said first circumferential trough and a second circumferential rib aligned with said second circumferential trough; revolving said arbor in an orbit about a longitudinal axis of said die; increasing the diameter of said orbit while revolving said arbor so as to force said arbor against an inner surface of said pipe element; pinching said pipe element between said first circumferential rib and said first circumferential trough while revolving said arbor in said orbit of increasing diameter, thereby causing a portion of said pipe element between said first and second circumferential troughs to move radially inwardly away from said die such that a gap exists between said die and said pipe element thereby forming said groove, said groove having a smaller outer diameter than the outer diameter of the remainder of said pipe element.