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:
Sep. 24, 1991
Filed:
May. 31, 1989
Dixon Newbold, Providence, RI (US);
Other;
Abstract
A hand pump having a cylinder and piston in which the piston head is formed with an annular channel having an opening in the base of the annular channel in free communication with the interior of a hollow piston rod. A pair of radially-projecting stops extend outwardly from the base of the channel adjacent the opening. A pair of O-rings are positioned within the channel with one on either side of the stops with the O-rings having an inner diameter closely fitting the surface of the base and an outer diameter when in an unstressed position engage in a sliding relation the inner surface of the cylinder. Chambers are formed on either end of the piston head and are provided with valve inlets. In operation the O-rings are alternately flexed about the stops to create an air passage between the flexed O-ring and the inner surface of the cylinder depending upon the relative direction of movement of the head to the inner surface of the cylinder wall, whereby air may be forced from one or the other chambers through the hole and into the hollow piston rod.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile