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US 5,809,643 AGranted
Method for making piston rings
OwnerE. Grant Swickinventor
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OwnerE. Grant Swickinventor
Estimating the term…
A method for making non-circular piston rings which will precisely sealably conform to the cylinder wall of an internal combustion engine. In accordance with the method a metal strip of special cross-sectional configuration is coiled about a specially configured mandrel which is non-circular in cross section. Preferably the coiling mandrel is provided with a circumferentially interrupted thread form that has a zero helix angle along most of its circumference. During the coiling operation, using this type of mandrel, the metal strip is preformed at specific locations along its length into an angled configuration to form a coil body having a plurality of coils that have a zero helix angle along most of their circumference and a relatively steep helix angle for a short distance. After the coil is formed, the helix angle portions are cut therefrom to provide a plurality of generally planer, interrupted rings.
A method of making interrupted rings using a forming mandrel of non-circular cross section having a plurality of circumferentially extending grooves comprising the steps of:
A method of making interrupted rings from a length of metal strip using a forming mandrel of non-circular cross section comprising the steps of:
A method of making interrupted rings from an elongated metal strip using a forming mandrel of non-circular, cross section that is provided with a plurality of circumferentially extending, longitudinally spaced apart grooves, each of which is interrupted along its circumference, said method comprising the steps of:
A method of making interrupted rings using a forming mandrel of non-circular cross section comprising the steps of:
Dependencies are inferred from the claim text.