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:
May. 01, 2001
Filed:
Mar. 02, 1998
Salvatore J. Dedola, New Kensington, PA (US);
Mark W. Hitchins, Sewickley, PA (US);
Medrad, Inc., Indianola, PA (US);
Abstract
The present invention provides a plunger for use in a syringe and a syringe comprising such a plunger. The plunger includes a pressure member extending around the circumference of a generally cylindrical body of the plunger. The pressure member is in substantially sealing contact with the plunger body. The pressure member is sufficiently flexible to be forced radially outwardly to exert force upon the inner wall of the syringe as a result of increased fluid pressure upon forward motion of the plunger. The pressure member thereby forms a substantially sealing engagement with the inner wall of the syringe. In one embodiment, the pressure member comprises a flange attached at a rearward portion of the flange to a body of the plunger. The flange extends forward and radially outward to form a circumferential channel between the flange and the body of the plunger. In another embodiment, the pressure member comprises a resilient O-ring seated in a seating formed around the circumference of the body of the plunger. The seating comprises a ramp portion having a forward radius that is smaller than a rearward radius thereof.