Safety syringe for intravenous injection with a guided plunger

• US 6,117,107 A
• Filed: 02/24/1998
• Issued: 09/12/2000
• Est. Priority Date: 09/16/1997
• Status: Expired due to Fees

• Current Assignee: Formosa Medical Devices Incorporated
• Original Assignee: Long-Hsiung Chen
• Inventors: Chen, Long-Hsiung
• Primary Examiner(s): Coggins, Wynn Wood
• Assistant Examiner(s): Blyveis, Deborah
• Application Number:
  US09/028,576
• Time in Patent Office: 931 Days
• Field of Search: 604/110, 604/181, 604/187, 604/195, 604/198, 604/218, 604/228, 128/919
• US Class Current: 604/110
• CPC Class Codes: A61M 2005/3106 Plugs for syringes without needle
• CPC Class Codes: A61M 2005/3224 Means to disalign the needle tip and syringe nozzle
• CPC Class Codes: A61M 2005/342 Off-center needles, i.e. needle connections not being coaxial with the longitudinal symmetry axis of syringe barrel
• CPC Class Codes: A61M 5/322 Retractable needles, i.e. disconnected from and withdrawn into the syringe barrel by the piston devices for protecting guide needles in combination with catheters A61M25/0612

Abstract

A safety syringe for intravenous injection with a guided plunger is provided that comprises a barrel, a needle unit, and a plunger. An outlet is eccentrically disposed on the top of the barrel. The needle unit includes a needle and a spindle shaped needle holder mounted inside the outlet. A connecting stem has an arrowhead shaped mortise disposed under the spindle shaped needle holder. A plunger has a plunger head on the top thereof with an arrowhead shaped tenon eccentrically disposed thereon. A supporting plate disposed under the plunger head has two guide notches matched with two longitudinal guide strips inside the barrel, so that the arrowhead shaped tenon aligns with the needle unit. After completion of the injection, the arrowhead shaped tenon and the needle unit are connected together, the needle unit can then be pulled into the barrel and subsequently deformed.

Claims

1. A safety syringe for intravenous injection, comprising:

a barrel having a conically shaped front portion and an opposing rear portion with an outwardly extended flange formed thereat, said barrel having a bore formed therein and said rear stem having an opening formed in open communication with said bore, said barrel having a pair of guide strips formed on a wall surface interior to said bore and a reduced tubular outlet eccentrically disposed on said conically shaped front portion and in open communication with said bore;

a needle unit having a spindle shaped needle holder releasably coupled to said tubular outlet and a cannulated needle affixed to said needle holder to extend from a first end thereof, said needle holder having a second end and a connecting stem extending therefrom, said connecting portion having an inclined bottom surface and an opening extending from said bottom surface with an arrowhead shaped mortise formed in said opening and inclined with respect to an axis of said needle;

a plunger slidingly disposed in said bore of said barrel, said plunger having (a) a plunger head having an upper conical surface, (b) an arrowhead shaped tenon eccentrically disposed on said plunger head and extending from said upper conical surface thereof in aligned relationship with said mortise of said connecting stem, (c) a sealing ring circumscribing said plunger head, and (d) a supporting plate disposed beneath said plunger head and supporting said sealing ring, said supporting plate having a pair of guide notches formed therein for respectively receiving said pair of guide strips therein, said plunger being displaced toward said front portion of said barrel to express a fluid from said barrel and engage said mortise with said tenon, subsequent displacement of said plunger toward said rear portion of said barrel thereby displaces said needle unit into said bore of said barrel and said needle set being offset with respect to said tubular outlet by cooperation between (i) said inclined bottom surface of said connecting portion, (ii) said conical surface of said plunger head, and (iii) said inclined mortise; and

, a tubular needle cap having a closed distal end for insert into said tubular outlet subsequent to said needle unit being displaced into said bore.