Dampening device for spring movement

• US 5,913,843 A
• Filed: 11/26/1997
• Issued: 06/22/1999
• Est. Priority Date: 11/26/1997
• Status: Expired due to Term

• Current Assignee: Saf-T-Med, Inc. (Becton, Dickinson & Co)
• Original Assignee: Saf-T-Med, Inc. (Becton, Dickinson & Co)
• Inventors: Jentzen, S. William
• Primary Examiner(s): McDermott, Corrine
• Assistant Examiner(s): Thanh, LoAn H.
• Application Number:
  US08/980,136
• Time in Patent Office: 573 Days
• Field of Search: 604/218, 604/110, 604/134, 604/181, 604/186, 604/187, 604/207, 604/226, 604/240, 604/242, 604/243, 604/246, 604/195, 604/198, 128/919
• US Class Current: 604/110
• CPC Class Codes: A61M 5/3234 Fully automatic needle retraction, i.e. in which triggering of the needle does not require a deliberate action by the user

Abstract

Timing of movements of a spring between a stressed and a free state is delayed by dampening the spring movement through incorporation of a component having a restricted access diameter whereby frictional contact of the spring through the component will prolong the time required to move the spring between states to enhance control of the spring actuation.

Claims

1. A non-reusable safety syringe comprising:

(a) a cylindrical barrel having first and second barrel ends and an inside diameter wall there between;

(b) a chamber for receipt of fluid within said barrel and between said first and second barrel ends;

(c) a plastic hollow plunger extendable into said barrel through the first end of said barrel, and selectively moveable from an expanded position toward an expended position immediate the second barrel end;

(d) a hollow needle in secured relationship relative to the second end of the barrel; and

movable into the plunger;

(e) spring biasing means, in initially secured relationship relative to the second end of the barrel for biasing the needle towards the hollow plunger; and

(f) dampening means for controlling the time of effective movement of said spring biasing means as the hollow needle is moved into the plunger, whereby upon movement of said plunger to the expended position, fluid is discharged and the hollow needle is thereafter moved into the plunger.

2. The safety syringe of claim 1 wherein the dampening means comprises an elongated collar operatively positionable relative to said barrel and including an inner wall defining a restricted diameter passageway therethrough, the diameter of said restricted passageway being less than the diameter of the outer surface of said spring biasing means, whereby the outer surface of said spring biasing means frictionally engages an inner wall of said collar to delay movement of said spring biasing means therethrough during activation of movement of said hollow needle toward said hollow plunger.