Blind threaded fastener forming technique
AssigneeAVK Industrial Products, A Division of SPS Technologies Inc.
InventorMichael J. Weedon
Life of this patent
Estimating the term…
Abstract
A simplified method for producing internally threaded blind fasteners includes cold forming of the thin deformable walls of the fastener into bowed out sections by reverse extrusion to form deep grooves, and subsequent further cold forming to increase the diameter of this thin walled portion of the fastener to form it into bowed out sections. Three or more or even five or more sections may be formed, to increase the “pull-out” resistance by increasing the “footprint” of the deformed sections of the blind fastener.
Claims20
A method for forming a blind fastener comprising the steps of:
- (a) cutting off a generally cylindrical slug of metal from a length of cylindrical metal stock;
- (b) cold forming the metal slug to size while starting a central recess;
- (c) deepening the central recess and initial formation of the flange or head of the fastener by further cold forming;
- (d) cold forming knurling and longitudinal cuts substantially through the side walls of the fastener by backward extrusion;
- and
- (e) completing the fastener flange, or head, bowing out sections of the side walls, and punching out a small central slug of metal to fully open the center of the fastener, all by a cold forming step;
- and
- wherein the foregoing steps are performed in a single multi-station header type machine.
A threaded blind fastener comprising:
- a thin walled body portion;
- a head at one end of said body portion;
- a cold rolled internally threaded outer portion at the other end of said body portion;
- said thin walled body portion being cold formed into bowed-out sections by reverse or backward extrusion;
- and
- said fastener being annealed to facilitate collapsing of said sections.
A method for forming a blind fastener comprising the steps of:
- cold forming a generally cylindrical metal slug to size while starting a central recess;
- deepening the central recess and starting the formation of the flange or head of the fastener by further cold forming;
- cold forming longitudinal cuts substantially through the side walls of the fastener;
- and
- completing the fastener flange, or head, bowing out sections of the side walls, and punching out a small central slug of metal to fully open the center of the fastener, all by cold forming.
A method of forming a blind fastener in which an intermediate work piece has been prepared having a central recess, comprising the steps of:
- deepening the central recess and concurrently cold forming knurling and longitudinal cuts substantially through the side walls of the work piece;
- and
- bowing out the side walls in separate sections in a further cold forming step to facilitate subsequent deformation of said sections.
Dependencies are inferred from the claim text.