Safety syringe

[0001] 1. Field of the Invention

[0002] The present invention relates to a syringe, and especially to a safety syringe for protecting a user from being pricked with a used needle.

[0003] 2. Description of the Related Art

[0004] With modern developments in medical technology, people understand clearer about routes of infection. One of the infection routes is blood contact. If a person is pricked with a used needle, the used needle can transfer diseases to the person. Therefore, the used needle must be disposed carefully. However, a user is pricked easily with the used needle during inserting the used needle into a cap.

[0005] The objective of the present invention is to provide a safety syringe that can avoid pricking with a used needle during the used needle inserts into a cap.

[0006] To achieve the foregoing objective, a safety syringe has a syringe body, a casing, a plunger, a connector and a needle hub with a needle. The syringe body has a front end, a rear end and a neck. The neck is formed on the front end. The casing is mounted around the syringe body and has a front end, a rear end, an inner surface, and a fix unit. The fix unit is formed on the inner surface near the rear end. The plunger is mounted in the syringe body. The connector is mounted around the neck and has a middle ring, a front tube, a rear tube and a notch. The middle ring is formed between the front tube and the rear tube. The rear tube is mounted around the neck and has an outer surface. The notch is formed around the outer surface of the rear tube. The needle hub is mounted around the front tube. After injecting, a user pushes the rear end of the casing from the rear end to the front end of the syringe body so the needle hub with the needle is mounted in the casing and the connector engages with the fix unit. Then breaking the notch, the casing is detached from the syringe body and holds the needle inside.

[0007] Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

[0008] FIG. 1 is a perspective view of a first embodiment of a safety syringe in accordance with the present invention;

[0009] FIG. 2 is an explored perspective view of the first embodiment of the safety syringe in FIG. 1;

[0010] FIG. 3 is a perspective view of a connector of the safety syringe in FIG. 1;

[0011] FIG. 4 is a side view in partial section of the first embodiment of the safety syringe in FIG. 1;

[0012] FIG. 5 is a side view in partial section of the first embodiment of the safety syringe in FIG. 1 showing that the needle is inserted into a casing;

[0013] FIG. 6 is an operational side view in partial section of the first embodiment of the safety syringe in FIG. 1 showing that the safety syringe is broken at a notch;

[0014] FIG. 7 is a perspective view of a second embodiment of a safety syringe in accordance with the present invention;

[0015] FIG. 8 is a perspective view of a connector of the safety syringe in FIG. 7;

[0016] FIG. 9 is a side view in partial section of the second embodiment of the safety syringe in FIG. 7 showing that the needle is inserted into the casing;

[0017] FIG. 10 is an operational side view in partial section of the second embodiment of the safety syringe in FIG. 7 showing that the safety syringe is broken at a notch;

[0018] FIG. 11 is an operational side view in partial section of the second embodiment of the safety syringe in FIG. 7 showing that the syringe body is detached from the casing and the needle hub with the needle is kept inside the casing;

[0019] FIG. 12 is an operational side view in partial section of a third embodiment of a safety syringe in accordance with the present invention;

[0020] FIG. 13 is a perspective view of a connector of the safety syringe in FIG. 12;

[0021] FIG. 14 is an operational side view in partial section of a forth embodiment of a safety syringe in accordance with the present invention; and

[0022] FIG. 15 is a side view in partial section of a connector of the safety syringe in FIG. 14.

[0023] With reference to FIGS. 1 to 3, a safety syringe in accordance with the present invention comprises a syringe body (10), a casing (20), a plunger (30), a connector (50), a needle hub (60) and an optional plug (40).

[0024] The syringe body (10) is tubular and comprises a front end (11), a rear end (12), an outer surface, an outer diameter, a neck (141), an outer tube (142), an optional annular protrusion (15), at least one optional projection (16). The neck (141) is formed on the front end (11). The outer tube (142) is formed around the neck (141), extends from the syringe body (10), is coaxial with the neck (141) and further comprises an inner thread. The annular protrusion (15) is formed on the outer surface near the rear end (12). The at least one projection (16) is respectively formed on the rear end (12) and opposite to each other to allow a user to hold the syringe body (10) during injection.

[0025] The casing (20) is tubular, is mounted around the syringe body (10) and comprises a front end (21), a rear end (22), an inner diameter, an inner surface, a fix unit and an optional guide slot (25) as shown in FIG. 7. The rear end (22) attaches with the annular protrusion (15). The inner diameter of the casing (20) is larger than the outer diameter of the syringe body (10). The fix unit is formed on the inner surface near the rear end (22) and may comprise a slope (23) and an annular recess (24) or may comprise at least one resilient tab and a protruding ring or may comprise multiple protruding rings (26) as shown in FIG. 9. The slope (23) is formed on the inner surface. The annular recess (24) is formed in the slope (23).

[0026] The plunger (30) is mounted in the syringe body (10), and comprises a front end, a rear end, a base (31) and a push head (32). The base (31) is formed on the front end. The push head (32) is formed on the rear end. Pushing the push head (32) ejects the medical solution from the syringe body (10).

[0027] The plug (40) is mounted around the base (31) of the plunger (30).

[0028] With further reference to FIGS. 3, 8 and 13 to 15, the connector (50) is tubular and hollow, is mounted around the neck (141) and comprises a front tube (51), a rear tube (52), a middle ring (53), a notch (54, 55) and an optional fix taper (56). The middle ring (53) is formed between the front tube (51) and the rear tube (52) and further comprises an outer circumference, a guide protrusion (531) and multiple limit protrusions (532). The guide protrusion (531) is formed on and protrudes from the outer circumference of the middle ring (53), slides in the guide slot (25) and is higher than the limit protrusions (532). The limit protrusions (532) are separately formed on and protrudes from the outer circumference of the middle ring (53) in equal interval. The limit protrusions (532) attach to the protruding rings (26), when pushing the rear end (22) of the casing (20) from the rear end (12) to the front end (11) of the syringe body (10). The rear tube (52) is mounted around the neck (141) on the syringe body (10) and comprises an outer surface, a proximal end, a distal end and an optional rib (521). The rib (521) is formed around the outer surface on the distal end and attaches the inner thread in the outer tube (142). The notch (54, 55) is formed around the outer surface of the rear tube (52) and may be formed incompletely around the rear tube (52), such as the notch (55) as shown in FIG. 13, so the casing (20) does not detach completely from the syringe body (10) after breaking the notch (55) as shown in FIG. 12. Preferably, the notch (54, 55) is formed around the outer surface of the rear tube near the proximal end. The notch (54, 55) can be annular or a spiral. The fix taper (56) is mounted around the connector (50) and comprises a front end, a rear end, an outer surface, an inner surface, a groove (561) and a circumference protrusion (562). The groove (561) is mounted around the middle ring (53) and is formed around the inner surface on the front end. The circumference protrusion (562) is formed around the outer surface on the rear end and attaches with the annular recess (24) when the casing (20) is moved to the front end of the syringe body (10).

[0029] The needle hub (60) is mounted around the front tube (51) and comprises a needle (61). The needle hub (60) may screw, clamp, glue to, weld or stick on the front tube (51).

[0030] With reference to FIG. 4 to 6, 9 to 12 and 14, after injecting, a user pushes the rear end (22) of the casing (20) from the rear end (12) to the front end (11) of the syringe body (10). The middle ring (53) or the circumference protrusion (562) of the connector (50) will be wedged in the annular recess (24). Then, the user can hold the casing (20) in one hand and hold the syringe body (10) in the other to break the syringe body (10) at the notch (54, 55) so the casing (20) is detached from the syringe body (10) and the needle hub (60) with the needle (61) is kept inside the casing (20). Because the middle ring (53) or the circumference protrusion (562) of the connector (50) is wedged in the annular recess (24) and the notch (54, 55) is formed around the outer surface of the rear tube (52) near the proximal end, the needle hub (60) with the needle (61) is kept from being escaped from the casing (20). Therefore, the user will not be pricked by a used needle (61).

[0031] Even though numerous characteristics and advantages of the present invention have been set forth in the foregoing description, together with details of the structure and features of the invention, the disclosure is illustrative only. Changes may be made in the details, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.