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US 5,809,820 AGranted
Spring washer and method for making the same
AssigneeNissan Screw Co., Ltd.
InventorToshiaki Morimoto
Life of this patent
Estimating the term…
Abstract
A spring washer improves resistance to loosening of fasteners tightened thereon. The spring washer is stronger than prior art devices. On the upper and lower surfaces of the spring washer, approximately 1/5-1/4 of the width inward from the outer perimeter is formed without V-shaped grooves. The remaining flat portions are formed with V-shaped grooves in various patterns. These V-shaped grooves increase the coefficient of friction and resist loosening of the spring washer.
Claims3
A method for impressing grooves into surfaces of spring washers comprising the steps of:
- inserting a rolled material between at least two guide rollers and at least one pressing roller, said at least one pressing roller having knurling surfaces;
- inclining said at least one pressing roller to match an incline of said rolled material;
- adjusting a pressure applied to said rolled material by said at least one pressing roller to adjust a depth of said grooves which are pressed into said rolled material by said knurling surfaces of said at least one pressing roller;
- adjusting a position of said rolled material relative to said at least one pressing roller such that said grooves are not formed on a first portion of said rolling material, which abuts an outermost perimeter of said spring washer;
- feeding said rolled material through said at least two guide rollers and said at least one pressing roller such that said knurls of said at least one pressing roller impress grooves on said rolled material;
- and
- coiling said rolled material.
4 more elements
Dependencies are inferred from the claim text.