The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 21, 1978
Filed:
Oct. 26, 1976
Applicant:
Inventors:
Georges Boudet, Saint-Cyr-sur-Loire, FR;
Jacques Charpentier, Tours, FR;
Rene Vinel, Bourg-la-Reine, FR;
Jean-Claude Desmoulins, Conflans-Sainte-Honorine, FR;
Emmanuel DE Blic, Tours, FR;
Assignee:
SKF Compagnie d'Applications Mecaniques, Clamart, FR;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
E21B / ;
U.S. Cl.
CPC ...
254 / ;
Abstract
Hydraulic device for exerting a pre-stressing traction on bolts or pins comprises three stages, with each stage comprising a piston within a chamber. The thickness of the skirts of the piston increases from stage to stage in proportion to the pressure to which the piston of that stage is subjected during a stretching operation.