Safety syringe with retractable needle and universal luer...

Details Safety syringe with retractable needle and universal luer... Safety syringe with retractable needle and universal luer...

1998-06-01

2001-02-06

Kennedy, Sharon (Department: 3734)

Surgery

Means for introducing or removing material from body for...

Treating material introduced into or removed from body...

C604S195000, C604S240000

Reexamination Certificate

active

06183464

ABSTRACT:

TECHNICAL FIELD
The present invention relates to a syringe for medical and industrial applications and particularly relates to a syringe of a type having a needle which can be readily and easily withdrawn into the barrel for disposal purposes, can be sealed at both ends in a manner to reduce the volume of trash upon disposal, provides a double encapsulation of the needle within the syringe for disposal purposes and affords enhanced sealing at the distal end of the barrel as well as other features. Further aspects of the invention include a universal Luer coupling for forming either a Luer fit or a Luer lock.
BACKGROUND
Needlestick injuries among medical practitioners is and has been of tremendous concern because of the possibility for transmission of diseases, for example, the AIDS and Hepatitis B and C viruses and numerous other blood-borne pathogens. The vast majority of currently commercially available syringes do not protect the medical practitioner or those individuals involved in the disposal of syringes from needlestick injuries and consequent possibility of contracting these diseases.
A number of patents disclose syringes having needle-protecting features but most, for various reasons, have not appeared to any significant extent in the marketplace. See, for example, U.S. Pat. Nos. 4,592,744; 4,804,370; 4,542,749; 4,631,057; 4,425,120; 4,258,713; 4,266,544; 4,139,009; 4,774,964 and 4,507,117. These patents have addressed the problem in various ways but none have completely solved the problem or have been a commercial success.
The present invention is a result of various refinements made to assignee's efforts to design, develop and market a safety syringe of the type in which the needle is retractable within the syringe barrel and sealed. Prior syringe designs of applicants' assignee are reflected in U.S. Pat. No. 5,688,240, issued Nov. 18, 1997 and antecedent patents of assignee. While assignee's design demonstrates superior capabilities vis-a-vis the designs of the above-listed prior patents, further refinements as set forth herein are believed necessary to provide a fail-safe, easily usable retractable needle syringe. For example, in the prior design illustrated in assignee's U.S. Pat. No. 5,688,240, the disclosure of which is incorporated herein by reference, the connection between the plunger and needle-carrying adapter could be disrupted by forceful withdrawal of the plunger subsequent to that connection and prior to complete unthreading of the adapter relative to the barrel. While this might occur only rarely, if at all, there remained the possibility that the adapter could be left in the barrel end in a loosened condition leaving exposed a contaminated needle and potentially permitting leakage of fluids from the syringe. Additionally, while assignee's prior patent demonstrated a capacity to seal both ends of the syringe barrel for disposal, it relied on a threaded connection between the proximal end of the plunger, after it was broken off from the adapter, for threaded sealing engagement with the distal end of the barrel. While both ends of the barrel were fluid-sealed, this resulted in an elongated structure which, from a disposal standpoint, disadvantageously increased trash volume. Other refinements and improvements to assignee's prior syringe will be evident from the ensuing description.
DISCLOSURE OF THE INVENTION
In accordance with the present invention, there is provided a syringe comprised of an elongated, generally cylindrical barrel, having a reduced diameter distal end with female threads and a proximal end having at least one radially inwardly extending circumferential rib. The distal end of the barrel threadedly receives an adapter for mounting a needle, either as a Luer fit or Luer Lok or a needle integrally formed with the adapter whereby the passage through the needle and through the adapter affords communication between the interior of the barrel and the tip of the needle. A plunger is receivable in the barrel through its proximal end and has a distal end portion carrying a bung for sealing against the interior walls of the barrel. The proximal end of the plunger has a finger press which, in combination with a flange at the proximal end of the barrel, enables the practitioner to manipulate the plunger axially within the barrel.
In one aspect of the present invention, there is provided a unique engagement structure on the proximal and distal ends of the adapter and plunger, respectively, generally enabling the plunger to be pushed axially home to engage the adapter and unscrew the adapter from the barrel end, permitting the adapter with the needle carried thereby to be withdrawn into the interior of the barrel. As described in detail below, the adapter is withdrawn to the proximal end of the barrel. The projecting plunger body can then be snapped from the distal end of the plunger leaving the bung sealing the proximal end of the barrel and then inserted, broken end first, into the opposite distal end of the barrel. The plunger body is open in an axial direction along its centerline and, when fully inserted into the barrel, substantially surrounds but does not functionally contact the needle withdrawn in the barrel. The plunger also seals the distal end of the barrel upon full insertion whereby any fluids within the barrel and in prior contact with the needle are sealed in the barrel. It will be appreciated that this arrangement reduces the volume of the sealed syringe upon disposal in comparison with the volume of the syringe of the type illustrated in assignee's prior U.S. Pat. No. 5,688,240.
The unique engagement structure between the plunger and adapter of the present syringe includes an adapter engagement structure on the distal end of the plunger comprising a plurality of circumferentially spaced, teeth about a central recess, e.g., a bulbous recess, extending axially toward the adapter. Surrounding a central axially projecting bulbous portion of the adapter are a plurality of circumferentially spaced teeth projecting axially toward the plunger and forming mating engagement structure on the adapter. The plunger teeth as viewed from the side of the plunger looking toward the axis are generally triangularly-shaped, each terminating in an apex with at least one sloped or inclined side surface and an axially extending circumferentially facing drive surface along respective opposite sides of the apex. The plunger teeth also include a finger adjacent the apex end of each tooth which projects in a radial outward direction, leaving a recess between an axially facing contact surface of the finger and a base portion of the distal end of the plunger.
The mating engagement structure on the adapter includes a plurality of circumferentially spaced, axially extending teeth which, as viewed looking from the side toward the axis, have generally right triangularly-shaped projections terminating in apices. Each tooth has one inclined or sloping surface on one side of the apex and a driven surface on the opposite side of the apex. The teeth include a generally triangularly-shaped lug which is spaced radially outwardly of the hub of the adapter and has an axially facing contact surface, i.e., an undercut, spaced from an annular seat forming part of the adapter. When the plunger is pressed axially to engage the adapter, it will be appreciated that each plunger tooth will engage one of the sloping surfaces of the adapter teeth, i.e., either the sloping surface of the tooth or of the lug. Upon further axial movement of the plunger into the barrel relative rotation of the plunger and adapter will occur to locate the apices of the plunger teeth at the lands between the adapter teeth. When the plunger has been pressed into its furthest axial position, the axially facing surfaces of the plunger and adapter teeth are enabled for engagement with one another upon relative rotation of the plunger and adapter. That is, when the plunger and adapter teeth are relatively rotated to engage the plunger drive surfaces against the adapter driven

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