Self-locking safety disposable syringe with needle protection after use

• US 7,267,664 B2
• Filed: 11/16/2004
• Issued: 09/11/2007
• Est. Priority Date: 12/03/2003
• Status: Active Grant

• Current Assignee: RMB Ergon SRL
• Original Assignee: RMB Ergon SRL
• Inventors: Rizzo, Alberto
• Primary Examiner(s): DeSanto; Matthew F.
• Application Number:
  US10/988,696
• Publication Number:
  US 20050124934A1
• Time in Patent Office: 1,029 Days
• Field of Search: 604/110, 604/181, 604/187, 604/263, 604192-198, 128/919
• US Class Current: 604/110
• CPC Class Codes: A61M 2005/3231 Proximal end of needle captured or embedded inside piston head, e.g. by friction or hooks
• CPC Class Codes: A61M 2005/3241 Needle retraction energy is accumulated inside of a hollow plunger rod
• 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 5/5066 Means for preventing re-use by disconnection of piston and piston-rod

Abstract

The invention refers to the field of self-locking safety disposable syringes with needle protection after use. The syringe comprises a hollow barrel (1) ending on its lower side with an internal seat (2) adapted to receive a hub (3) carrying a cannula (4). A hollow driving rod (5) adapted to house a spring (6) is inserted in the hollow barrel. Such rod is closed at its lower end by an extracting element (8) that can slide into the hollow driving rod. The extracting element has an annular notch (9) in which a sealing ring rubber gasket (10) is housed that seals the internal wall of the hollow barrel (1). The extracting element (8) with related sealing ring gasket (10) form a liquid sucking and compressing plunger.

Claims

1. A self-locking safety disposable syringe with needle protection after use, comprising:

a hollow barrel (1) having at one end an internal seat (2);

a hub (3) carrying a cannula (4);

a hollow driving rod (5), housing a spring (6), disposed in the hollow barrel (1); and

an extracting element (8) on the rod for extracting the hub (3) from the internal seat (2),

wherein the extracting element (8) has an annular notch (9) in which an annular sealing gasket (10) is disposed, of such a size as to seal against the internal wall of the hollow barrel (1) both when sucking and when compressing the liquid to be injected;

said extracting element (8) with said sealing gasket (10) operating as a sucking and compressing piston;

and wherein on the inside of said end of the hollow barrel (1) two small semicircular projections (21) and (22) are provided, that are able to press, by reaction to the thrust of an operator'"'"'s thumb on the hollow driving rod (5) of the extracting element (8), against a flat part (11) of the sliding extracting element (8) and simultaneously to form a small circular recess (23) for housing the annular sealing gasket (10) when, at the end of an injection, said sealing gasket (10) separates from said annular notch (9).

2. A syringe according to claim 1, wherein on said flat part (11) a recess (12) is provided for a male engaging head (15) of the hub (3), at the end of the injection, said male engaging head (15) having two deep longitudinal slots (16) and (17) that are mutually orthogonal so that the cannula-holding hub (3) is cut into four parts between the head (15) and a male circular rib (18).

3. A syringe according to claim 2, wherein, under the projections (21) and (22), the internal surface of the seat (2) has a female annular groove (24) adapted to house the circular rib (18).

4. A syringe according to claim 3, wherein the internal diameter of the recess (12) of the sliding extracting element (8) is less than the diameter of the male engaging head (15) so that, at the end of the injection, during the insertion of the male engaging head (15) in the female engaging notch (12), the head (15), due to its longitudinal slots (16) and (17) that make it resilient, is pressed in such a way as to free the male circular rib (18) from said groove (24).

5. A syringe according to claim 3, wherein the female groove (24) is moved towards the needle tip in order to keep the male rib (18) pushed towards it, so that the syringe liquid holding capacity is provided between a male frustum of cone (19) of the hub (3) and a female frustum of cone (20) on the internal surface of the seat (2) of the hollow barrel (1) that always remain pressed together.

6. A syringe according to claim 1, wherein, on the external surface of the extracting element (8), circular stop (13) is provided, adapted to abut against a circular step (14) on an internal front part of the hollow driving rod (5).

7. A syringe according to claim 1, wherein said annular sealing gasket (10) is an O-ring.