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:
Mar. 30, 1999
Filed:
Sep. 12, 1996
Etienne Perrin, Pirey, FR;
Draftex Industries Limited, Edinburgh, GB;
Abstract
A gas compression spring comprises a gas-filled cylinder in which a piston carrying a hollow piston rod is slidable and divides the interior of the cylinder into first and second chambers. Over part of the length of the cylinder, a groove is provided in the cylinder wall. Gas pressure within the cylinder causes the piston to drive the piston rod outwards of the cylinder, this being permitted by the groove which allows transfer of gas pressure between the two chambers. When the piston reaches the end of the groove, such gas pressure transfer ceases and movement of the piston rod stops. External manual force applied to a control rod, extending through the hollow interior of the piston rod, unseals an opening at the end of the piston rod which brings the two chambers into communication again. Gas pressure transfer can now take place between the two chambers via the interior of the piston rod. Movement of the piston rod outwardly of the cylinder under the pressure exerted by the gas now re-commences, but can be halted at any desired position by release of the force manually exerted on the control rod.