Assembly of plunger and needle hub safety syringe needle device

An improved assembly of plunger and needle hub for a safety syringe needle device is disclosed, which comprises a syringe barrel, a needle hub and a plunger. The syringe barrel is shaped as a tube and has an interior periphery thereof shaped as a straight tube. The needle hub is inserted into the syringe barrel and has an integrated combining ring, which is bent inward as a hook and has a crease whereon the combining ring is bent inward. The needle hub has a nozzle jutting out of the syringe barrel for connecting a needle. The plunger comprises a plug for being fitly received by the syringe barrel and a front end thereof can be pierced through and coupled with the combining ring.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to an improved assembly of plunger and needle hub for a safety syringe needle device and, more particularly, to a safety syringe needle device with a retractable needle hub that has integrated combining ring formed as inward-bent hooks for being engaged with a plunger and capable of being retracted back to the syringe accompanying retreat of the plunger.

2. Description of Related Art

A conventional safety syringe needle device is illustrated throughFIGS. 8 and 9, which is primarily composed of a tubular syringe barrel5, a needle hub6and a plunger7, wherein the interior periphery of the syringe barrel5is shaped as a straight tube, and inside the syringe barrel5, a flange51is provided adjacent to the front end thereof while two opposite notches52are arranged at the front end of the syringe barrel5.

Said needle hub6is inserted into the syringe barrel5and has a retaining ring61, which comprises a plurality of retaining hooks62, each having a hook portion621for being engaged with the notches52of the syringe barrel5and a snap segment622settled at the outer edge thereof. As there is an interval between the retaining hooks62and the retaining ring61, the syringe barrel5can hold the needle hood6by implementing the flange51to retain the retaining ring61and press upon the retaining hooks62. Moreover, the retaining ring61further comprises a nozzle63, which is jutting out of the syringe barrel5and comprises a recess631positioned corresponding to the retaining hooks62. In the meantime, each of the retaining hooks62has a combining portion623positioned corresponding to the recess631so that when the combining portions623is engaged with the recess631, the retaining hooks62can be squeezed and the hook portions621can be withdrawn from engaging the syringe barrel5. Furthermore, a combining portion64is extended from the needle hub6and is composed of a plurality of flexible pieces641each having a retaining portion642. Also, a needle65and a sheath66can be sleeved onto the nozzle63.

The plunger7comprises a plug71for being fitly received by the syringe barrel5. The plug71further has a combining portion72protruding at the front end thereof wherein the combining portion72includes two wings721each attached by an extended retaining piece722and the combining portion72is thereby formed as a diamond-shaped structure. Thus, the combining portion72and the combining portion64can be assembled by piercing the combining portion72through the combining portion64to make the retaining pieces722retained by the retaining portions642of the combining portion64.

Accordingly, as the plural pieces641of the combining portion64of the needle hub6are quite complicated in the structure, the components need to be made very precisely in order to ensure appropriate combination with the combining portion72and the manufacturing cost can be consequently raised.

Hence, a need exists for an improvement on the conventional assembly of plunger and needle hub for a safety syringe needle device.

SUMMARY OF THE INVENTION

The present invention has been accomplished under these circumstances in view. It is one objective of the present invention to provide an improved assembly of plunger and needle hub for a safety syringe needle device with a retractable needle hub that has an integrated combining ring formed as inward-bent hooks for being engaged with a plunger and capable of being retracted back to the syringe accompanying retreat of the plunger. The disclosed assembly facilitates safe and convenient use. Additionally, because of the relatively uncomplicated structure of the integrated needle hub and combining ring, the manufacturing cost of the disclosed assembly can be significantly reduced.

To achieve these and other objectives of the present invention, the improved assembly of plunger and needle hub for a safety syringe needle comprises:

a tubular syringe barrel, which is shaped as a tube and has an interior periphery thereof shaped as a straight tube wherein two opposite ends of the syringe barrel are respectively defined as a front end and a rear end;

a needle hub, which is inserted into the syringe barrel and comprises a retaining ring, which is sleeved by a packing ring at the external edge thereof, an accommodating room formed at one end thereof and a an axially tapered combining ring wherein, a crease is formed between the interior periphery of the combining ring and the accommodating room is defined between the retaining ring and the combining ring, wherein the retaining ring can be bent inward to the accommodating room, and the needle hub further comprises a nozzle, which is jutting out from the syringe barrel and for being mounted by a needle; and

a plunger, which comprises a plug for being fitly received by the syringe barrel wherein the plug further has a packing ring sleeved around the edge thereof and the front end of the plug can be coupled with the combining ring of the needle hub.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Please refer toFIGS. 1 to 6, which describe a preferred embodiment of the present invention. It is to be understood that the recited figures and embodiment are for illustrating and not intended to limit the structure of the present invention.

According to one embodiment of the present invention, a safety syringe needle device may comprise some components, which are explained in more detail below.

A tubular syringe barrel1, which is shaped as a tube and has an interior periphery thereof shaped as a straight tube wherein two opposite ends of the syringe barrel1are respectively defined as a front end11and a rear end12. Further, a flange13is settled at the interior periphery of the syringe barrel1adjacent to the front end11thereof, and the flange13has an incline cut131thereon. A retaining portion14is provided at the interior periphery at the rear end12of the syringe barrel1. According to the present embodiment, the retaining portion14is substantially composed of four inward-bent hooks141, which are equally spaced. A peripherally enlarged annular segment15is extended from the rear end12of the syringe barrel1and is separated from the outer side of the inward-bent hooks141with an interval16.

A needle hub2is inserted into the rear end11of the syringe barrel1and is retained by the flange13. The needle hub2comprises a retaining ring21, which is sleeved by a packing ring211at the external edge thereof and has an accommodating room23formed at one end thereof. Also, the retaining ring21comprises an integrally extended and axially tapered combining ring22, which comprises a plurality of teeth221protruding at the upper edge of the combining ring22. Furthermore, a crease222is formed between the interior periphery of the combining ring22and the retaining ring21, and a through hole223is settled at the lower edge of each of the said teeth221and comes into close proximity with the crease222to provide further flexibility to the combining ring22, whereby when the combining ring22is bent toward the accommodating room23, it can be formed into a hook. The opposite end of the retaining ring21has a nozzle24, which is jutting out from the syringe barrel1and for being mounted by a needle25. Further, the needle25can be sheathed within a sheath251.

A plunger3comprises a plug31for being fitly received by the syringe barrel1. The plug31further has a packing ring311sleeved around the edge thereof. For being assembled to the needle hub2, in the present embodiment, a combining portion32is jutting out from the front end of the plug31, wherein an annular protrusion33situated at the front end of the combining portion32has a sectional diameter smaller than the diameter of the accommodating room23of the needle hub2and the combining portion32has an acute-angled annular recess321formed adjacent to the edge of the annular protrusion33.

Reference is now made toFIG. 5. After using the syringe needle device, when a user pushes the plunger3back to the syringe barrel1, since the diameter of the annular protrusion33is larger than the diameter of the extreme of the combining ring22of the needle hub2, the annular protrusion33of the plunger3has to be shoehorned through the combining ring22of the needle hub2to enter the accommodating room23of the needle hub2. Afterward, the combining ring22of the needle hub2can recover and embed itself in the annular recess321to couple with the plunger3.

As illustrated inFIG. 6, when the plunger3is subsequently pulled backward, the needle hub2is drawn inward the syringe barrel1accordingly. Therefore, the needle hub2and needle25can be retracted and accommodated in the syringe barrel1then. When the plunger3is pulled, the inward-bent hooks141of the retaining portion14retains the needle hub2so as to prevent the needle hub2and needle25from undesirably coming off the syringe barrel1. After that, the part jutting out from the syringe barrel1of the plunger3can be trimmed off and the needle hub2and needle25can be kept in the syringe barrel1safely.

Accordingly, the disclosed assembly of plunger and needle hub for a safety syringe needle device is advantageous by not only facilitating safe and convenient use, but also significantly reducing the mold-making cost because of the relatively uncomplicated structure of the needle hub2and combining ring22.

It is absolute that various embodiments may exist for realizing the concept of the present invention. For instance, inFIG. 7, according to a second embodiment of the present invention, the combining ring22of the needle hub2is composed of four separated pieces.

Although some particular embodiments of the invention have been described in details for purposes of illustration, it will be understood by one of ordinary skill in the art that numerous variations will be possible to the disclosed embodiments without going outside the scope of the invention as disclosed in the claims.