Method for forming a fluted fastener

摘要

A new machine for and method of manufacturing fluted pin fasteners and the pins produced thereby are disclosed which utilize a circular grinding arrangement of a plurality of grinders which grind flutes into a threaded pin. An internally threaded collar threads onto the pin. When the collar engages a surface of a work piece, resistance to further threading increases. When sufficient resistance to threading occurs, the driver deforms the lobes of the collar radially inward toward the axis of the collar. Material of the collar positioned internally from the lobes responds to deformation of the lobes and flows radially inward into the flutes of the pin to lock the collar, pin, and work piece together. The driver then rotates freely, and a joint has been made with a predetermined axial load thereby locking the component parts together. The apparatus grinding the flutes into the pins comprises a vibratory feed bowl loading threaded pins into a four station rotary drum assembly rotationally driven by a drive mechanism through a plurality of stations.