Field of the Invention:

[0001] The present disclosure relates to a disposable syringe, and more specifically to a structure of a single-use syringe.

Background of the Invention:

[0002] The need for a single-use syringe comes from the concern in the transfer of infectious diseases such as AIDS, and more particularly to some intravenous drug users who routinely share and reuse syringes. Although there are some requirement or procedure for a proper disposal of used syringes, failure of following such procedure may be due to the urgency of the situation or negligence.

[0003] There are many various designs of single-use syringe in the present market but all lack a straight forwardness, simplicity, reliability, in both use and fabrication, along with a self-containment of all parts.

Summary of the Invention:

[0004] These and other needs are addressed by various embodiments of the disclosure, wherein an approach is provided for a single-use syringe.

[0005] According to one aspect of an embodiment of the disclosure, a device of a syringe comprises a needle assembly, a barrel, an upper plunger, lower plunger and a plunger seal. The barrel has a front portion with smaller diameter connecting to the needle assembly, a rear portion with larger diameter, a shoulder and a first teeth layer. The shoulder is formed between the front portion and the rear portion. The first teeth layer formed inside the rear portion. [0006] The upper plunger is configured for moving in the barrel. The upper plunger has a round shaped bottom mounted at a first end, a first flange formed at a second end and a second flange formed adjacent to the first flange.

[0007] The lower plunger has a second teeth layer and a third teeth layer formed inside the lower plunger. The space between the second teeth layer and the third teeth layer defines a holding portion that holds the round shaped bottom of the upper plunger. The plunger seal is placed between the lower plunger and the front portion of the barrel.

[0008] Accordingly, the round shaped bottom can be entirely trapped inside the lower plunger after injection, and simultaneously the second flange is sheltered by the first teeth layer inside the barrel. The upper plunger is locked.

Brief Description of Drawings:

[0009] The disclosure is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings in which like reference numerals refer to similar elements and in which:

[0010] Fig. 1 is an exploded view illustrating a syringe in accordance with an embodiment of the present disclosure.

[0011] Fig. 2 is a close-up view illustrating the barrel in accordance with an embodiment of the present disclosure.

[0012] Fig. 3 is an exemplary diagram of the lower plunger in accordance with an embodiment of the present disclosure.

[0013] Figs. 4-7 are exemplary diagrams illustrating the implement of using a syringe in accordance with an embodiment of the present disclosure. Detail Description:

[0014] The structure of a single-use syringe is disclosed. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiment of the disclosure. It is apparent, however, to one skilled in the art that the present disclosure may be practiced without these specific details or with an equivalent arrangement.

[0015] With reference to Figs. 1 and 2, Fig. 1 is an exploded view illustrating a syringe in accordance with an embodiment of the present disclosure; Fig. 2 is a close-up view illustrating the barrel in accordance with an embodiment of the present disclosure. As shown in Figs. 1 and 2, a syringe comprises a needle assembly 1, a barrel 2, an upper plunger 3, lower plunger 4 and a plunger seal 5. The barrel 2 has a front portion 20 with smaller diameter connecting to the needle assembly 1, a rear portion 21 with larger diameter, a shoulder 22, a first teeth layer 23 and an optional third flange 24. The shoulder 22 is formed between the front portion 20 and the rear portion 21. The first teeth layer 23 formed inside the rear portion 21.

[0016] The upper plunger 3 is configured for moving inside the barrel 2. The upper plunger 3 has a round shaped bottom 30 mounted at a first end, a first flange 31 formed at a second end and a second flange 32 formed adjacent to the first flange 31.

[0017] As shown in Fig. 2, in one embodiment, the first teeth layer 23 of the barrel 2 comprises multiple transverse protuberances, and each protuberance projecting downwardly from an inner wall of the barrel 2. The third flange 24 is formed on an outer wall of the barrel 2 corresponded to the first teeth layer 23.

[0018] With further reference to Fig. 3, Fig. 3 is an exemplary diagram of the lower plunger in accordance with an embodiment of the present disclosure. In this embodiment, the lower plunger 4 has a second teeth layer 40 and a third teeth layer 41 formed inside the lower plunger 4. The space between the second teeth layer 40 and the third teeth layer 41 defines a holding portion that holds the round shaped bottom 30 of the upper plunger 3 during injection. The plunger seal 5 is placed between the lower plunger 4 and the front portion 20 of the barrel 2.

[0019] The second teeth layer 40 of the lower plunger 4 is formed at an end, almost close to the top, of the lower plunger 4, and the other end of the lower plunger

4 connects to the plunger seal 5. The second teeth layer 40 is formed with multiple transverse protuberances, and each protuberance projecting downwardly from an inner wall of the lower plunger 4. The third teeth layer 41 comprises multiple transverse protuberances projecting radially from the inner wall of the lower plunger. A locking portion is defined in a space between the third teeth layer 41 and the bottom of the lower plunger 4.

[0020] With reference to Figs. 4 to 7, Fig. 4 is an exemplary diagram of a syringe in an initial state in accordance with an embodiment of the present disclosure; Fig.

5 illustrating the syringe is in a pulling state in accordance with an embodiment of the present disclosure; Fig. 6 illustrating the syringe is in a pushing state in accordance with an embodiment of the present disclosure; and Fig. 7 is an exemplary diagram of a syringe in an locked state in accordance with an embodiment of the present disclosure.

[0021] Initially, as shown in Fig. 4, the syringe of current disclosure is assembled. The plunger seal 5 is moved toward the front portion 20 that touches the bottom of the barrel 2 (e.g., the shoulder of the barrel 2), which in order to remove all the air before injection. The round shaped bottom 30 is firmly held inside the holding portion 60. In other words, the lower plunger 4 is engaged to the upper plunger 3.

[0022] The third teeth layer 41 of the lower plunger 4 prevents the upper plunger 3 going totally inside the lower plunger 4 when a person pushing too hard on the first flange 31 for removing air.

[0023] Filling the syringe with medicine after air being discharged, as shown in Fig. 5, the upper plunger 3 is pulled with the lower plunger 4 moving toward the first teeth layer 23. The upper plunger 3 stopped when the medicine drawn up to a desired amount. The first teeth layer 23 ensures the upper plunger 3 will not pull out from the barrel 2, and the second teeth layer 40 prevents the upper plunger 3 being pull out from the lower plunger 4.

[0024] The upper plunger 3 is then being pushed, as shown in Fig. 6, to make the lower plunger 4 moving toward the shoulder 22. Until the plunger seal 5 touches the bottom of the barrel 2, all medicine is being injected. [0025] After injection, as shown in Fig. 7, the upper plunger 3 is then further pushed to make the round shaped bottom 30 entirely trapped inside the locking portion 61 of the lower plunger 4. Simultaneously, the second flange 32 is inserted through the first teeth layer 23 inside the barrel. The upper plunger 3 is locked. The syringe is no longer usable. [0026] It is noted that the first and the second teeth layer are formed with multiple transverse protuberances projecting downwardly from the surrounding walls. Once the upper plunger is locked, applying external force for detachment will break the protuberances. [0027] In contrast, there is no additional and/or external means or components to make syringe locked from reuse, the syringe of the present invention provides a straight forwardness, simplicity, reliability, in both use and fabrication, along with a self-containment of all parts. [0028] While the disclosure has been described in connection with a number of embodiments and implementations, the disclosure is not so limited but covers various obvious modifications and equivalent arrangements, which fall within the purview of the appended claims. Although features of the disclosure are expressed in certain combinations among the claims, it is contemplated that these features can be arranged in any combination and order.