Disposable hypodermic syringe

• US 5,114,410 A
• Filed: 01/18/1991
• Issued: 05/19/1992
• Est. Priority Date: 01/17/1990
• Status: Expired due to Term

• Current Assignee: Syrinworld, S.L.
• Original Assignee: Jaime Caralt Batlle
• Inventors: Caralt Batlle, Jaime
• Primary Examiner(s): YASKO JR, JOHN D
• Application Number:
  US07/642,303
• Time in Patent Office: 487 Days
• Field of Search: 604/195, 604/198, 604/192, 604/187, 604/263, 604/110, 604/218, 604/220
• US Class Current: 604/195
• CPC Class Codes: A61M 2005/3235 triggered by radial deflection of the anchoring parts between needle mount and syringe barrel or needle housing, e.g. spreading of needle mount retaining hooks having slanted surfaces by engagement with correspondingly shaped surfaces on the piston at the end of an injection stroke
• 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
• CPC Class Codes: A61M 5/502 for blocking the piston
• CPC Class Codes: A61M 5/508 Means for preventing re-use by disrupting the piston seal, e.g. by puncturing

Abstract

A disposable hypodermic syringe, comprising a tube, with its front part narrowed and adapted to receive a hypodermic needle, and a hollow piston capable of sliding through the inside of the tube; obturating devices laid across and held in operative position by the head of the needle; a spring, that tends to push the needle towards the inside of the tube; a closing device of the piston'"'"'s cavity; and irreversible joining devices to fit other complementary joining devices placed at the head of the needle. The obturating devices are composed of a discoid part made of a slightly flexible material, having a central countersunk hole to receive the head of the needle that passes through it. This discoid part has, on its front side, appendages adapted to operate on the retention devices as the discoid part is pushed forward by the front end of the piston, when it completes its operative run. The retention devices are constituted by many flexible tongues which rise from the wall of the tube at a slanting angle, pointing forward and inward, and which are set so that they become fitted into a ring-shaped external groove made around the outside of the needle'"'"' s head, from where they are removed as they are bent by means of the pushing action of the appendages of the obturating discoid part.

Claims

1. A disposable hypodermic syringe designed to be used only once, comprising:

a tubular barrel having a leading end and a trailing end and a longitudinally extending sidewall having a radially inwardly facing internal surface;

said tubular barrel further including at said leading end a leading end part which necks down in internal diameter at an internal shoulder and extends longitudinally with a bore having a smaller internal diameter than that of said sidewall;

said leading end part having a leading end out through which said bore opens out of said barrel;

means defining a plurality of flexible tongues arranged in within said barrel in a ring, said tongues having outer ends mounted to said sidewall of said barrel adjacent a trailing end of said leading end part of said barrel, said tongues obliquely projecting radially inwardly and axially towards said leading end of said leading end part from said outer ends thereof, terminating in respective radially inner ends, so as to partially internally obdurate said barrel adjacent said internal shoulder;

a hypodermic needle having a longitudinal bore, a leading end arranged to be penetrated into a subject, when exposed from said barrel, and a trailing end disposed within said barrel;

said needle, between said leading and trailing ends thereof, extending longitudinally within said bore;

said hypodermic needle, adjacent said trailing ends thereof having an enlarged head which at said trailing end provides a countersunk opening into said longitudinal bore of said needle and a flaring external shoulder;

a discoidal part disposed in said barrel and being made of flexible material;

said discoidal part having a radially outer portion circumferentially disposed in sliding sealing engagement with said inwardly facing internal surface of said sidewall of said barrel and being arranged, prior to use of said needle, so as to have a longitudinally bore of said discoidal part slidingly receive and circumferentially surround said enlarged head of said needle, with a trailing end of said discoidal part engaged against said flaring external shoulder of said enlarged head of said needle;

said discoidal part further having on a leading end thereof appendage means which extend longitudinally towards said leading end of said needle and engage said flexible tongues of sites radially intermediate said inner and outer ends of said flexible tongues;

means defining a spring cavity in said leading end part of said barrel, said spring cavity having a radial shoulder formed therein adjacent where said bore of said leading end part opens out of said barrel;

a compression coil spring having a leading end engaged against said radial shoulder of said spring cavity, and having a trailing end engaged with said enlarged head of said needle;

said compression coil spring being at least partially housed in said spring cavity, and spiralingly surrounding said needle;

said radially inner ends of said flexible tongues, prior to use of said needle, being axially spaced from said internal shoulder of said leading end part of said barrel;

said enlarged head of said needle further having a radially outwardly opening circumferentially extending groove in which, prior to use of said needle, said radially inner ends of said flexible tongues are seated, with said compression coil spring thereby held in an axially compressed condition;

a piston telescopically received in said barrel through said trailing end of said barrel and arranged to be slid axially from an outer position in which a leading end of said piston is substantially spaced from said head of said needle, thereby defining a fluid-receiving cavity within said barrel, and an inner position, in which the leading end of said piston engages said discoidal part and pushes said discoidal part sufficiently towards said leading end of said needle as to cause said appendage means on said discoidal part to flex said flexible tongues towards said internal shoulder sufficiently to unseat said radially inner ends of said flexible tongues from said groove, thereby releasing said spring to recover from its compressed condition, and thus retract said needle into said barrel;

said piston having a cavity extending longitudinally therein and opening centrally of said leading end of said piston, to receive said enlarged head and a longitudinally adjoining intermediate portion of said needle, as needle is retracted into said barrel by recovery of said spring;

said spring having sufficient travel while recovering as to sufficiently retract said needle into said barrel that said leading end of said needle no longer emerges from said bore of said lead end part of said barrel.

2. The disposable hypodermic syringe of claim 1, further comprising:

means defining a radially inwardly opening circumferential groove in said piston, within said piston cavity, near said leading end of said piston, this groove, prior to use of said needle, receiving a discoidal button having a central protuberance which is axially aligned with and faces, but is axially spaced from, said countersunk opening into said longitudinal bore of said needle, said discoidal button being so arranged that as said piston is advanced from its outer position to its inner position, said protuberance is forced into said countersunk opening and said discoidal button is dislodged from said radially inwardly opening circumferential groove in said piston, so as to be driven on said enlarged head of said needle, axially further into said cavity of said piston.