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. 01, 1998
Filed:
Feb. 29, 1996
David Schiff, Highland Park, NJ (US);
Paul Mulhauser, New York, NY (US);
Medi-Ject Corporation, Minneapolis, MN (US);
Abstract
A plunger/ram assembly adapted for a hypodermic fluid injector having a nozzle body defining a fluid chamber and an orifice communicating with the chamber. The plunger/ram assembly comprises a plunger adapted to be movably positioned in the chamber and a ram assembly. The ram assembly is operatively connected to the plunger for drawing fluid into and expelling fluid out the chamber through the orifice. The ram assembly includes first and second driving members spaced apart by a preselected free travel distance and a resilient biasing member having a preselected preload. The resilient biasing member is operatively disposed for maintaining the free travel distance when the preload is greater than a force applied to the first driving member. The maximum fluid pressure generated by the plunger/ram assembly is controlled by a free travel distance or gap existing between first and second driving members before the injector is fired. Prior to firing, the gap is accurately maintained during movement of the plunger/ram assembly by a resilient spring member. This arrangement ensures that the injected fluid will be delivered to the patient's body at a desired pressure sufficient to properly pierce the patient's skin or the like.