AND SAFETY SYRINGE

Field of Invention

The present invention relates to a needle protection device, and particularly to a needle protection device with a slideable sleeve which can prevent a needle used in a medical instrument such as a syringe or a blood collector from causing accidental stick, as well as a safety needle assembly or safety syringe having such a needle protection device with a slideable sleeve.

Background of the Invention

In medical practices, a medical instrument with a pointed needle is used extensively, for example a syringe or a blood collector. These medical instruments are not only used and processed by professionals in medical establishments, but also often used and processed by non-professionals at home, for example, a diabetes patient injects insulin on his own.

Since the needle of the medical instrument such as the syringe is exposed outside after use and likely to injure related persons, which causes substantial difficulty to collection and treatment. Such sticks might lead to bacterial infection. Furthermore, when the used needle is used again, there is a risk of cross infection.

In order to prevent occurrence of accidental sticks and cross infection, people advance a disposable syringe whose needle is retractable after use. However, such syringe is complicated in structure and high in cost. Furthermore, when the syringe whose needle is retractable is moved from place to place after it completes take-in of a liquid medicament during use thereof, the needle is still exposed and still has a risk of accidental sticks.

Summary of the Invention

In order to prevent accidental sticks and reuse the needle with a simple structure and low costs, the present invention provides a needle protection device with a slideable sleeve and a safety syringe using the needle protection device.

The needle protection device according to the present invention is used in combination with the needle comprising a needle seat and a needle tube installed on the needle seat, and comprises a collar and a slideable sleeve. The collar is in a cylindrical shape having a longitudinal axis and can be sleeved on the needle seat in a fixed manner. The slideable sleeve is in a cylindrical shape, has an upper end portion and a lower end portion, and can be sleeved on the collar and slide between a retracted position and an extended position along the collar. At the retracted position, the upper end portion of the slideable sleeve is sleeved on the collar, and at the extended position, the lower end portion of the slideable sleeve is sleeved on the collar, wherein an outer surface of the collar and an inner surface of the lower end portion of the slideable sleeve are respectively formed with mutually matching locking mechanisms. When the slideable sleeve is at the extended position, it can be locked on the collar in an inseparable manner.

Preferably, the locking mechanisms comprise one or more bosses which are formed on the outer surface of the collar and extend in the longitudinal axial direction, and at least one snap groove formed on the inner surface of the lower end portion of the slideable sleeve; when the slideable sleeve rotates relative to the collar at the extended position, at least one said boss may be snap-fitted in at least one said snap groove in an inseparable manner.

Still preferably, the locking mechanisms comprise a flange circumferentially provided on one of the outer surface of the collar and the inner surface of the slideable sleeve, and at least one pair of protrusions provided on the other of the outer surface of the collar and the inner surface of the slideable sleeve, wherein a distance of the pair of protrusions in the longitudinal axial direction is not smaller than a height of the flange.

Preferably, a longitudinal guide groove extending in the longitudinal axial direction is formed on an outer surface of at least one said boss; in snap groove-free regions on the inner surface of the slideable sleeve is provided at least one guide rib which extends between the upper end portion and the lower end portion and is configured to slide in the longitudinal guide groove in the longitudinal axial direction; the guide rib and the longitudinal guide groove are structured in a way that when the slideable sleeve rotates relative to the collar, the guide rib can disengage from the longitudinal guide groove.

Alternatively, in snap groove-free regions on the inner surface of the slideable sleeve is provided at least one longitudinal guide groove which extends between the upper end portion and the lower end portion; on the outer surface of at least one said boss is formed a guide rib which extends in the longitudinal axial direction and is configured to slide in the longitudinal guide groove in the longitudinal axial direction; the guide rib and the longitudinal guide groove are structured in a way that when the slideable sleeve rotates relative to the collar, the guide rib can disengage from the longitudinal guide groove.

Preferably, a convex point is formed on one of the inner surface of the slideable sleeve and the outer surface of the collar, a depression is formed on the other of the inner surface of the slideable sleeve and the outer surface of the collar, the convex point can be snap fitted in the depression in a separable manner when the slidable sleeve slides to the extended position.

Certainly, a convex point more protruding than other portions of the guide rib may be formed on the guide rib; a depression deeper than other portions of the longitudinal guide groove is formed in the longitudinal guide groove; when the slideable sleeve slides to the extended position, the convex point is snap fitted in the depression in a separable manner. At the location of the depression is formed a circumferential guide notch which extends circumferentially and has a depth smaller than that of the depression; when the slideable sleeve rotates relative to the collar at the extended position, the convex point can slide in the circumferential guide notch.

Another preferred embodiment of the present invention can be made apparent from the following depictions and claims.

The needle protection device and safety syringe according to the present invention are simple in structure and low in costs, and can prevent a medical instrument having a needle such as a syringe or a blood collector from accidental sticks upon use and after use, and can prevent these medical instruments from reuse after use.

Brief Description of Drawings

Fig.l is a sectional view of a safety needle assembly in a before-use state according to one embodiment of the present invention.

Fig.2 is a sectional view of the safety needle assembly shown in Fig.l when a protective cap is taken off and a slideable sleeve is located at a retracted position.

Fig.3 is a sectional view of the safety needle assembly shown in Fig.l when the slideable sleeve is located at an extended position.

Fig.4 is a perspective view of a cross section taken along line A-A in Fig.3.

Fig.5 is a sectional view of the safety needle assembly shown in Fig.l in an injection state.

Fig.6 is a sectional view of the safety needle assembly shown in Fig.l when the slideable sleeve is rotated upon completion of the injection.

Fig.7 is a perspective view of a cross section taken along line B-B in Fig.6. Fig.8 is a perspective view of a collar of the safety needle assembly shown in

Fig.l.

Fig.9 is a front view of the collar shown in Fig.8.

Fig.10 is a top view of the collar shown in Fig.9.

Fig.11 is a sectional view taken along line C-C in Fig.10.

Fig.12 is a sectional view taken along line D-D in Fig.ll.

Fig.13 is a perspective view of the slideable sleeve of the safety needle assembly of Fig.l.

Fig.14 is a front view of the slideable sleeve of Fig.13.

Fig.15 is a sectional view taken along line E-E of Fig.14 after an external flange is omitted.

Fig.16 is a sectional view taken along line F-F of Fig.15 after an external flange is omitted.

Fig.17 is a sectional view taken along line G-G in Fig.15. Fig.18 is a sectional view taken along line H-H in Fig.15.

Fig.19 is a perspective view of a barrel of the safety needle assembly of Fig.l. Fig.20 is a front view of the barrel of Fig.19.

Fig.21 is a top view of the barrel of Fig.19.

Fig.22 is a sectional view taken along line I-I in Fig.21.

Fig.23 is a perspective view of a protective cap of the safety needle assembly of

Fig.l.

Fig.24 is a front view of the protective cap of Fig.23.

Fig.25 is a top view of the protective cap of Fig.23.

Fig.26 is a sectional view taken along line J-J in Fig.25.

Fig.27 is a sectional view of a safety needle assembly according to another embodiment of the present invention upon completion of injection.

Fig.28 is a sectional view of the safety needle assembly of Fig.27 when the slideable sleeve is pulled up upon completion of injection.

Fig.29 is a sectional view of the safety needle assembly of Fig.27 after the slideable sleeve is pulled up and rotated upon completion of injection.

Fig.30 is a sectional view taken along line K-K in Fig.28.

Fig.31 is a sectional view taken along line L-L in Fig.29.

Fig.32 is a perspective view of a collar of the safety needle assembly shown in Fig.27.

Fig.33 is a top view of the collar shown in Fig.32.

Fig.34 is a perspective view of the slideable sleeve of the safety needle assembly of Fig.27.

Fig.35 is a top view of the slideable sleeve of Fig.34.

Fig.36 is a sectional view taken along line M-M in Fig.35.

Fig.37 is a perspective view of a snap cap of the safety needle assembly of Fig.27.

Fig.38 is a sectional view of the snap cap of Fig.37.

Fig.39 illustrates another embodiment of the present invention, wherein a protective cap is provided. Fig.40 is a view showing the slideable sleeve in the embodiment of Fig.39 is located at an extended position.

Fig.41 is a longitudinal sectional view of the slideable sleeve.

Fig.42 is a sectional view after the slideable sleeve position shown in Fig.41 rotates 90° about a longitudinal axis.

Fig.43 is a sectional view when the present invention is applied to a syringe having a plastic outer sheath.

Fig.44 is a view illustrating another state of the present invention of Fig.43.

Fig.45 is a sectional view when the present invention is applied to another syringe having a plastic outer sheath.

Fig.46 is a view when the slideable sleeve of the present invention shown in Fig.45 is located at an extended position.

Detailed Description of Preferred Embodiments

Preferred embodiments of a needle protection device with a slideable sleeve and a safety syringe using such a needle protection device according to the present invention are described in detail with reference to the figures.

Fig.l is a view of a safety needle assembly before using according to one embodiment of the present invention. The safety needle assembly comprises a needle seat 8, a needle tube 6 mounted on the needle seat 8, a collar 1 fixed on the needle seat 8, and a slideable sleeve 2 sleeved on the collar 1 and provided slideable along the collar 1, wherein the needle seat 8 and the needle tube 6 forms a needle, and the collar 1 and the slideable sleeve 2 form the needle protection device according to the present invention. The safety needle assembly shown in Fig.l further comprises a barrel 4, a push rod 5 and a rubber piston 3 mounted at an upper end of the push rod

5. The barrel 4, the push rod 5 and the rubber piston 3 may be integral parts of the known syringes in the art and will not be described in detail.

In the present application, the needle seat 8 may be an individual member mountable on the barrel 4, or may be integrally formed with the barrel 4 as part of the barrel 4 (as shown in Fig.l). In the present application, a term indicating a direction, such as "up", "down", etc., is with respect to the pages of the figures, not an absolute direction.

The safety needle assembly further comprises a protective cap 7 encapsulating the needle tube 6 therein. The protective cap 7 may be one of various suitable structures known in the art. For example, meanwhile referring to Fig.23-Fig.26, a top portion 71 of the protective cap 7 is closed, and a bottom portion 74 of the protective cap 7 is open. An upper end portion 72 and a lower end portion 73 are provided between the top portion 71 and the bottom portion 74. The upper end portion 73 may have a certain taper, and a plurality of reinforcing ribs extending in an up-down direction (namely, longitudinally) may be formed on an outer surface of the upper end portion 72. The lower end portion 73 is configured to be provided around an outer surface of an upper end portion of the slideable sleeve 2.

In order to reliably prevent the needle tube 6 from contacting the top portion 71 of the protective cap upon assembling, a step 76 may be formed between the upper end portion 72 and the lower portion 73 so that an inner surface of the step 76 abuts against an upper end face 18 of the slideable sleeve 2 (concurrently referring to Figs.8, 9 and 11) to form a predetermined space between the needle tube 6 and the top portion 71 of the protective cap. Alternatively, or on the basis of the above configuration, an outwardly convex external flange 29 may be formed on the outer surface of the upper end portion of the slideable sleeve 2 (concurrently referring to Figs.13 and 14) so that an edge of the bottom portion 74 of the protective cap 7 abuts against the external flange 29. It may be appreciated that at this time, the inner surface of the step 76 may not be in contact with the upper end face of the slideable sleeve 2. Besides, as shown in Fig.13 and Fig.14, a plurality of ribs 30 in a direction of a longitudinal axis 21 are formed on the outer surface of the slideable sleeve 2 above the external flange 29, to increase a friction force between them and the inner surface of the lower end portion 73 of the protective cap 7, and prevent the protective cap 7 from rotating or disengaging accidentally in the direction of the longitudinal axis.

Then referring to Figs.8-12, they illustrate an embodiment of a collar of the needle protection device of the present invention. In this exemplary embodiment, the collar 1 is a cylinder shape having a longitudinal axis 10. Although in the example shown in the figures, the collar 1 is approximately cylindrical, the present invention is not limited to this, so long as the needle tube 6 is adapted to pass therethrough and provided around the needle seat 8, that is to say, so long as the shape of the collar 1 matches the shape of the needle seat 8.

The collar 1 may be fixedly mounted on the needle seat 8 via any of various known structures in the art. For example, concurrently referring to Fig.20-Fig.22, on the outer surface of the needle seat 8 may be formed a plurality of longitudinally extending ribs 81, and outwardly convex protrusions 82 are formed on the ribs 81, for example at upper ends of the ribs 81. Correspondingly, referring to Fig.8 and Fig.11, grooves 19 extending in the longitudinal axis 10 are formed on the inner surface of the collar 1, and a recess 20 is formed for example at an upper end of the groove 19 (meanwhile referring to Fig.12). When the collar 1 is mounted on the needle seat 8, the ribs 81 slide along the grooves 19 until the protrusions 82 snap fit in the recesses 20 so that the collar 1 cannot rotate relative to the needle seat 8, nor can slide longitudinally relative to the needle seat 8 so that the collar 1 is fixedly provided around the needle seat 8. The collar 1 may be provided around the needle seat 8 by interference fit, or via a raised portion circumferentially which is provided along the inner surface of the collar 1 and snap fits in an indented potion formed circumferentially along the outer surface of the needle seat 8, wherein the raised portion and the indented portion may be in any suitable shape, preferably an inverted taper shape so that the collar can be easily mounted on the needle seat and cannot easily slide off the needle seat.

As shown in Figs.8, 9, 10 and 12, a plurality of bosses 12 extending in the direction of the longitudinal axis 10 are formed on an outer surface 11 of the collar 1. The figures show four bosses 12 distributed symmetrically. However, it should be appreciated that the present invention is not limited to this. Preferably, the bosses 12 are integrally molded with the outer surface 11 of the collar.

The bosses 12 may extend along an entire longitudinal length of the collar 1, an upper end thereof may extend beyond the collar 1 and forms an upper end face 18; a lower end of the boss 12 may flush with a lower end of the collar 1 and forms a lower end face 17 (meanwhile referring to Fig.11). When the slideable sleeve 2 is located at a retracted position, referring to Figs. l, 2 and 5, an upper flange 24 in the slideable sleeve 2 (see Fig.14-Fig.16) abuts against the upper end face 18 to prevent the fall of the slideable sleeve 2. When the slideable sleeve 2 is located at an extended position, referring to Fig.3 and Fig.6, the lower end face 17 of the collar may abut against or engage the lower flange 25 of the slideable sleeve 2 (see Fig.14-Fig.16) to reliably prevent the slideable sleeve 2 from being pulled away from the collar 1 at the extended position.

Fig.13-Fig.18 illustrate an embodiment of the slideable sleeve 2 in the needle protection device of the present invention, wherein in the sectional views shown in Figs.15-18, the external flange 29 of Fig.13 and Fig.14 is not shown.

The slideable sleeve 2 may be cylindrical, but not limited to a circular cross section so long as the slideable sleeve 2 can be provided around the collar 1. The slideable sleeve 2 has a longitudinal axis 21. When the slideable sleeve 2 is provided around the collar 1, preferably the longitudinal axis 21 of the slideable sleeve 2 overlaps the longitudinal axis 10 of the collar.

The slideable sleeve 2 is provided around the collar 1, more specifically, around on the bosses 12 on the outer surface of the collar 1, and is slideable along the outer surface of the bosses 12 between the retracted position and the extended position. Referring to Figs.l, 2 and 5, when the slideable sleeve 2 is in the retracted position, an upper end portion 22 of the slideable sleeve 2 is sleeved around the collar 1, whereupon the needle tube 6 is exposed outside the slideable sleeve 2; referring to Figs.3 and 6, when the slideable sleeve 2 is in the extended position, a lower end portion 23 of the slideable sleeve 2 is sleeved around the collar 1, whereupon the needle tube 6 is shrouded by the slideable sleeve 2.

It should be appreciated that the slideable sleeve 2 is divided into the upper end portion 22 and the lower end portion 23 only for ease of understanding. The upper end portion 22 generally corresponds to the portion of the slideable sleeve 2 sleeved around the collar 1 when at the retracted position, and the lower end portion 23 generally corresponds to the portion of the slideable sleeve 2 sleeved around the collar 1 when at the extended position.

As a preferred embodiment, a longitudinal slide guide mechanism may be formed between the inner surface of the slideable sleeve 2 and the outer surface of the boss 12. Referring to Figs.15-17, a guide rib 26 extending in the direction of the longitudinal axis 21 is formed on the inner surface of the slideable sleeve 2 between an upper flange 24 and a lower flange 25. The figures show two guide ribs 26 distributed symmetrically. But the present invention is not limited to this. Referring to Figs.8, 9, 10 and 12, a longitudinal guide groove 16 is formed on the outer surface of the boss 12 in the direction of the longitudinal axis 10. The guide rib 26 can slide in the longitudinal guide groove 16 in the direction of the longitudinal axis 10 or 21 to constitute the longitudinal slide guide mechanism to guide the slideable sleeve 2 to slide longitudinally relative to the boss 12.

A cross section where the guide rib 26 mates with the longitudinal guide groove 16 is shaped and sized so that when the slideable sleeve 2 rotates relative to the collar 1, the guide rib 26 can disengage from the longitudinal guide groove 16. In other words, the guide rib 26 is engaged with the longitudinal guide groove 16 circumferentially in a separable manner.

Although the longitudinal guide groove 16 is formed on all of the four bosses 12 shown in the figures, the longitudinal guide groove 16 may be formed on only two bosses 12, corresponding to the guide ribs 26.

As stated above, in order to temporarily retain the slideable sleeve 2 at the retracted position shown in Figs.l, 2 and 5, one or more projections 31 are formed on the inner surface of the upper end portion 22 of the slideable sleeve 2. In the embodiment as shown in Figs.15, 16 and 18, there are four symmetrically-distributed projections 31, wherein two projections 31 are respectively formed at the upper end of the two guide ribs 26. However, the present invention is not limited to this. Corresponding to the projections 31, a circumferential notch 15 is formed at the upper end portion of each boss 12 of the collar 1 (see Figs.8 and 9). When the slideable sleeve 2 is located at the retracted position, the projections 31 is snap fitted in the circumferential notch 15 in a separable manner so that the slideable sleeve 2 is temporarily held at the retracted position.

The so-called "separable manner" means that members snap-fitted together or engaged together can separate from each other under a suitable external force.

In order to temporarily hold the slideable sleeve 2 at the extended position shown in Figs.3 and 6, referring to Fig.15 and 16, a convex point 27 which is more convex than the remaining portions of the guide rib 26 and in the shape of a hemisphere or a water droplet may be formed on the guide rib 26, preferably at the lower end of the guide rib 26. Correspondingly, in the longitudinal guide groove 16 of the boss 12 is formed a depression 13 with a depth greater than the remaining portions of the longitudinal guide groove 16 (see Figs.8 and 9). When the slideable sleeve 2 is located at the extended position, the convex point 27 is snap-fitted in the depression 13 in a separable manner so as to temporarily hold the slideable sleeve 2 at the extended position and meanwhile prevent the locking of the slideable sleeve caused by accidental rotation of the slideable sleeve.

Although in the embodiment shown in the figure, the longitudinal guide groove 16 of each boss 12 has one depression 13, and each guide rib 26 has one convex point 27, the object of the present invention can be achieved so long as there are at least a pair of corresponding convex point 27 and the depression 13, though preferably more than two pairs of convex points 27 and depressions 13 are symmetrically distributed circumferentially.

It should be appreciated that the longitudinal guide groove 16 and the guide rib 26 are not requisite, so, as far as the retention at the extended position, the convex points 27/depressions 13 may be provided without any relationship to the longitudinal guide groove 16 and guide rib 26.

At least one snap groove 28 is formed on the inner surface of the lower end portion 23 of the slideable sleeve 2. The figure shows two symmetrically-distributed snap grooves 28. As clearly shown in Fig.17 and Fig.18, the snap groove 28 may be defined by a ridge 32 which is circumferentially formed on the inner surface of the slideable sleeve 2 and has a substantially barb-shaped cross section. In the embodiment shown in the figures, the snap groove 28 is encompassed by three ridges 32 and the lower flange 25. The snap groove 28 is structured in a way that when the slideable sleeve 2 slides between the retracted position and the extended position, the snap groove 28 does not interfere the boss 12 of the collar 1 ; when the slideable sleeve 2 rotates relative to the collar 1 at the extended position, the boss 12 is snap-fitted in the snap groove 28 in an inseparable manner.

The so-called "inseparable manner" means that if members snap-fitted together or engaged together are to be separated, a very large force is needed to achieve the separation, even permanent damages are caused to the members snap-fitted together or engaged together during the separation.

In order to guide the slideable sleeve 2 to rotate relative to the boss 12, a circumferential slide guide mechanism may be formed between the inner surface of the slideable sleeve 2 and the outer surface of the boss 12. As shown in Fig.8 and Fig.9, a circumferential guide notch 14 is formed at the location of the depression 13 on the boss 12, and a depth of the depression 13 is also greater than the circumferential guide notch 14. The convex point 27 on the inner surface of the slideable sleeve 2 can slide along the circumferential guide notch 14, and guide the slideable sleeve 2 to rotate relative to the boss 12 to constitute the circumferential slide guide mechanism.

Then referring to Fig. l-Fig.7, what is described is a method of using the safety needle assembly having the needle protection device of the present invention.

Fig.l illustrates a before-use state of the safety needle assembly according to the present invention, the push rod 5 is completely received in the barrel 4, the collar 1 is fixed on the needle seat 8, the slideable sleeve 2 is retained at the retracted position, the protective cap 7 is provided around the slideable sleeve 2 to encapsulate the needle tube 6.

In use, the protective cap 7 is removed, the slideale sleeve 2 is temporarily retained at the retracted position in a way that the projections 31 on the inner surface of the slideable sleeve 2 is snap fitted in the circumferential notches 15 on the bosses of the collar, to prevent the slideable sleeve 2 from sliding and interfering in the operation. At this time, the push rod 5 is pulled downward to take in the liquid medicament, as shown in Fig.2.

In medical practice, usually the safety needle assembly which already takes in the liquid medicament is transferred from place to place, or might not be immediately used for injection after the take-in of the liquid medicament. In order to protect the needle tube 6 and prevent occurrence of accidental sticks after this procedure, the slideable sleeve 2 may be pushed upward and temporarily retained at the extended position in a way that the convex points 27 on the inner surface of the slideable sleeve 2 are snap fitted in the depressions 13 on the collar bosses 12, such that the needle tube 6 is surrounded by the slideable sleeve 2, as shown in Fig.3. When the slideable sleeve 2 is temporarily retained at the extended position, the bosses 12 on the collar 1 are located outside the snap grooves 28 of the slideable sleeve 2, as shown in Fig.4.

Fig.5 shows an injection state. Upon injection, an appropriate force is applied to push the slideable sleeve 2 back to the retracted position, and temporarily retain the slideable sleeve 2 at the retracted position in a way that the projections 31 on the inner surface of the slideable sleeve 2 are snap fitted in the circumferential notches 15 on the bosses of the collar, to prevent possible sliding of the slideable sleeve 2 from interfering during the injection process.

Fig.6 illustrates a state upon completion of injection. The slideable sleeve 2 is slided to the extended position again, then the slideable sleeve 2 is rotated related to the collar 1 so that the bosses 12 on the collar 1 are snap-fitted in the snap grooves 28 of the slideable sleeve 2 in an inseparable manner, so as to prevent accidental sticks of the needle tube 6 and meanwhile prevent reuse of the safety needle assembly, as shown in Fig.7.

Those skilled in the art should understand that the above description is only exemplary. Taught by the present invention, those skilled in the art may make diverse variations, modifications or substitutions to the above-described embodiments according to specific situations.

For example, the guide ribs 26 on the inner surface of the slideable sleeve 2 are interchangeable with the longitudinal guide grooves 16 on the bosses 12 of the collar, that is, the guide ribs may be formed on the outer surface of the bosses 12 while the longitudinal guide grooves may be formed on the inner surface of the slideable sleeve 2. Similarly, the convex points 27 on the inner surface of the slideable sleeve 2 are interchangeable with the depressions 13 on the bosses 12, and the projections 31 on the inner surface of the slideable sleeve 2 are interchangeable with the circumferential notches 14 on the bosses.

Again for instance, the convex points 27/depressions 13 and projections 31 /circumferential notches 14 are used to temporarily retain the slideable sleeve 2 at the extended position and the retracted position, but this structure is not requisite. For example, since the depth of the longitudinal guide grooves 16 is smaller than that of the depressions 13, the frictional force between the convex points 27 and the longitudinal guide grooves 16 is, on some occasions, sufficient to temporarily retain the slideable sleeve 2 at the extended position and the retracted position. Even if without the convex points, the frictional force between the slideable sleeve 2 and the bosses 12 may be designed to achieve the temporary retention at the extended position and the retracted position.

Figs.28-38 illustrate a safety needle assembly according to another embodiment of the present invention. Although these figures do not show the protective cap, the safety needle assembly of the instant embodiment may have the same protective cap as the protective cap shown in Figs.23-25, or any protective cap adapted to be sleeved on the upper portion of the slideable sleeve. Besides the needle protection device, the safety needle assembly of the instant embodiment may have the same structure as shown in Figs.1-27, or any suitable structure already known in the art. Only the needle protection device in the instant embodiment is described as follows.

Figs.27, 28 and 29 are sectional views illustrating that the slidable sleeve is pulled up and rotated upon completion of the injection of the safety needle assembly. In the needle protection device according to the instant embodiment, a collar 100 is fixed on the needle seat, a slideable sleeve 200 is slideable up and down along the collar 100 to an extended position or a retracted position.

Figs.32 and 33 illustrate the collar 100 in the safety needle assembly of the instant embodiment. The collar 100 is generally a hollow cylinder such as a circular cylinder and comprises ribs 130 formed on an inner surface thereof and bosses 110 formed on an outer surface 140 thereof. The ribs are located between the ribs 81 on the outer surface of the needle seat (referring to Figs.20 and 22), and may, upon installation, guides the collar to the needle seat and prevent the collar from rotating relative to the needle seat 8. The bosses 110 can be snap-fitted into snap grooves 223 on an inner surface of the slideable sleeve 200 so that the slideable sleeve 200 is fixed at the position shown in Fig.29, as shown in Figs.30 and 31 (which will be described in detail hereunder). The bosses 110 can further be used to guide guide ribs 220 (to be described in detail hereunder) on the inner surface of the slideable sleeve 200 to slide between the bosses 110 and prevent the slideable sleeve 200 from rotating relative to the collar 100.

In a preferred embodiment, a chamber 120 may be formed on an end wall 150 of the collar 100. The position of the chamber 120 corresponds to the boss 110 on an outer surface 140. The chamber 120 exists so that the boss 110 can generate certain elastic displacement in a radial direction, to help the boss 110 to be snap-fitted into the snap grooves 223 in the slideable sleeve 200 (referring to Figs.30 and 31).

Hereunder, reference is made to Figs.34-36 to describe the slideable sleeve 200 of the instant embodiment. The slideable sleeve 200 is generally a barrel, e.g., a circular barrel. Guide ribs 220 are formed on the inner surface of the slideable sleeve 200 in an axial direction of the slideable sleeve. The guide ribs 200 may be in variously forms so long as they are slideable on the bosses 110 of the outer surface 140 of the collar 100.

Those skilled in the art should appreciate that with regard to guiding the slideable sleeve 200 to slide along the collar 100 and preventing the slideable sleeve 200 from rotating relative to the collar 100, it is feasible that at least one boss 110 is provided between more than two guide ribs 220, and also that at least one guide rib 220 is provided between more than two bosses 110.

A lower portion of each of the guide ribs 220 forms a radially raised portion 221. A radially inwardly projecting distance of the radially raised portion 221 is designed in a way that when the slideable sleeve 200 is pulled up (referring to Fig.28), the slideable sleeve 200 is fixed at the extended position in a separable manner via an interference fit between the radially raised portion 221 and the outer surface 140 of the collar 100. A magnitude of the interference can be selected according to factors such as a material, weight and the like of the parts, or selected by means of experiments so that when the radially raised portion 221 contacts the outer surface 140 of the collar 100, the slideable sleeve 200 is fixed at the extended position shown in Fig.28; when the slideable sleeve 200 is pushed or pulled downwardly, the slideable sleeve 200 may be pulled or pushed back to the retracted position shown in Fig.27, i.e., the slideable sleeve 200 is fixed at the pulled-up position shown in Fig.28 in a separable manner. In use of the safety needle assembly, if the safety needle assembly which has already taken in the liquid medicament needs to be transferred (referring to Fig.3), the slideable sleeve 200 is fixed at the extended position in a separable manner to protect the needle tube out of contact during transfer.

When the slideable sleeve 200 is pulled up, a lower flange 211 protruding towards the center may be formed at a lower end of the slideable sleeve 200 to prevent the slideable sleeve 200 from disengaging from the collar 100 due to excessive force, as shown in Figs.28, 29, 35 and 36. An inner diameter of the lower flange 211 is smaller than an outer diameter of the outer surface 140 of the collar 100 so that the lower flange 211 can abut against the end wall 150 of the collar 100 to prevent the slideable sleeve 200 from being further pulled up.

Referring to Figs.30, 31 and 36, a snap groove 223 is formed on a lower portion of the radially raised portion 221. The boss 110 of the collar 100 is snap-fitted in the snap groove 223 in an inseparable manner. A cross-sectional shape of the boss 110 and the snap groove 223 may be one of rectangle, square, toothed shape, a swallow tail shape and T shape, or any known structure in the art that can prevent the boss 110 from disengaging from the snap groove 223.

In order to facilitate rotation of the slideable sleeve 200 relative to the collar 100 so as to snap fit the boss 110 into the snap groove 223, as shown in Figs.30, 31, 35 and 36, a circumferential outer edge 222 of the snap groove 223 may be formed as a ramp.

Referring to Fig.36, a slide-stopping protuberance 240 may be formed on an upper portion of the inner surface of the slideable sleeve 200. The slide- stopping protuberance 240 may be in any shape, including but not limited to a sphere, a cube, a cuboid, a cone and etc.. The slide-stopping protuberance 240 may be provided on the guide rib 220, or on the inner surface of the slideable sleeve outside the guide ribs. There can be any number of slide-stopping protuberances distributed at any desired position of the upper portion of the inner surface of the slideable sleeve 200. The slide- stopping protuberances at different positions can have different shapes. The slide- stopping protuberances 240 are designed in a way that when the slideable sleeve 200 is located at the position shown in Fig.27, the slide-stopping protuberances engage the outer surface 140 and/or bosses 110 of the collar 100 in a separable manner by means of interference fit with the outer surface 140 and/or protuberance 110 of the collar 100, thereby preventing the slideable sleeve 200 from moving relative to the collar 100, and preventing the slideable sleeve 200 from accidentally sliding towards a tip of the needle tube and interfering in normal performance of the injection particularly when the tip of the needle tube faces downwardly during the injection.

Those skilled in the art should understand that the slide-stopping protuberances can be provided on the collar, or simultaneous provided on the collar and the slideable sleeve.

Referring to Fig.27, as a preferred embodiment, an upper end portion of the slideable sleeve 200 may be connected to a snap cap 300. At a lower end of the snap cap 300 is formed an outwardly extending flange 340. Meanwhile, referring to Figs.27, 34 and 36, hook-like members 230 are formed at an upper end of the outer surface 210 of the slideable sleeve 200. The hook-like members 230 may be annular hook-like members as shown in the figure, or discrete hook-like members formed at several positions. A flange 340 of the snap cap 300 may be snap fitted in the hook-like member 230 so as to connect the snap cap 300 with the slidealbe sleeve 200. As shown in Figs.37 and 38, the snap cap 300 is in a shape of a barrel which inner shape may match the outer surface of the upper end of the slideable sleeve 200 so that the snap cap 300 can be provided around the outer surface of the upper end of the slideable sleeve 200. An upper end face 330 of the snap cap 300 extends from an upper end of the snap cap 300 towards the center, and forms a central hole 310. The central hole 310 can permit the needle tube or an upper portion of the needle seat to pass therethrough. Meanwhile, a diameter of the central hole 310 is smaller than an outer diameter of the slideable sleeve 200, and preferably smaller than an inner diameter of the slideable sleeve 200. Therefore, the upper end face 330 may abut against the top end of the slideable sleeve 200.

Since the snap cap 300 is connected together with the slideable sleeve 200, the upper end face 330 may abut against the top end of the slideable sleeve 200, so that in the state as shown in Fig.27, even without the above slide- stopping protuberances, the slideable sleeve 200 will not slide downwardly and disengage from the collar 100.

The safety needle assembly shown in Figs.28-38 and the safety needle assembly shown in Figs.1-27 have substantially the same operation mode, which will not be described in detail here.

Figs.39-46 illustrate another embodiment of the present invention, wherein the same reference number denotes the same part. As shown in Fig.39, the collar 1 is sleeved on the needle seat 8. The collar 1 may be fixed to the needle seat 8 in a manner as stated above. Here, the collar 1 is connected to the needle seat 8 in a way that a raised portion 101 circumferentially provided on the inner surface of the collar 1 is snap fitted into a recessed portion circumferentially formed on the outer surface of the needle seat 8. The raised portion and the recessed portion are preferably in an inverted cone so that the collar can be easily mounted on the needle seat and cannot easily disengage. The slideable sleeve 2 is sleeved around the collar 1 and is slideable up and down.

A flange 102 is circumferentially provided on the outer surface of the collar 1, at least one pair of protrusions 201 and 20 are formed on the inner surface of the lower end portion of the slideable sleeve 2, wherein a distance of one of pairs of protrusions along a longitudinal axial direction of the slideable sleeve is not smaller than a height of the flange 102 so that when the slideable sleeve is located at the extended position shown in Fig.40, the flange 102 crosses one of the pair of protrusions and is snap fitted between the pair of protrusions so that the slideable sleeve can be locked at the extended position. Preferably, two pairs of protrusions are employed. As shown in Figs.41 and 42, the protrusions 201 and 201 ' form one pair and are staggered 90 degrees as viewed along the longitudinal axial direction of the slideable sleeve, the other pair of protrusions are provided oppositely in a diametrical direction respectively. In order to help the slideable sleeve to slide from the retracted position to the extended position, the protrusion to be crossed by the flange may be produced in a wedge shape. Certainly, vice versa, at least one pair of protrusions may be formed on the outer surface of the collar 1, and a flange be circumferentially formed on the inner surface of the slideable sleeve. The relative position of the protrusions may be selected arbitrarily so long as the slideable sleeve is locked at the extended position.

As shown in Figs.39 and 40, an inwardly protruding upper flange 202 is formed on the inner surface of the upper end portion of the slideable sleeve. When the slideale sleeve is located at the retracted position, the upper flange can abut against the upper end portion of the collar to prevent the slideable sleeve from falling. The upper flange may be integrally formed with the slideable sleeve, or sleeved around the upper end portion of the slideable sleeve as an individual member.

As shown in Fig.39, a flange 102 is circumferentially formed on the outer surface of the collar 1, one or more protrusions 203 are formed on the inner surface of the slideable sleeve below the upper flange 202. Here, the protrusion here may be a local protrusion or a ring of protrusion. When the slidalbe sleeve is located at the retracted position, the protrusion can abut against a lower portion of the flange 102 on the outer surface of the collar so that the slideable sleeve can be axially fixed when being located at the retracted position. Certainly, this is not requisite. A height of the protrusion here is small so that the slideable sleeve may separate from the collar and thereby leave the retracted position.

Other details are identical with those of the previous embodiment and will not be described in detail any more here.

In addition, the needle protection device of the present invention may also be used for a conventional glass syringe. As shown in Figs.43-46, a plastic outer jacket 400 is sleeved around the conventional glass syringe 600. The plastic outer jacket 400 extends along an entire barrel length, a lower stop 401 with certain elasticity is provided between the lower portion of the plastic outer jacket and the push rod to snap fit the plastic outer jacket at the lower portion of the barrel, or the plastic outer jacket is fixed at the lower end of the barrel by press fit, as shown in Fig.45. The upper portion of the plastic outer jacket 400 may encompass the needle tube and thereby functions as the needle seat, as shown in Figs.43 and 44; the upper portion of the plastic outer jacket 400 may not encompass the needle tube and only extends to the position of the needle seat, as shown in Figs.45 and 46. The collar is sleeved on the upper portion of the plastic outer jacket in a fixed manner. The slideable sleeve is sleeved on the collar and slides between the retracted position and the extended position along the collar.

Therefore, the needle seat mentioned upon describing the present invention may refer to an upper portion of the plastic outer jacket, which is sleeved around the barrel and functions as the barrel. The above depictions regarding the needle seat also apply to the plastic outer jacket herein. This structure is partially adapted for prefilled products, such as prefilled insulin syringes.

In the embodiment, the protective cap may not only sleeve around the outer surface of the slideable sleeve, but also installed in an interior of the plastic outer jacket, as shown in Fig.45.

Although the present invention has been particularly described with reference to the accompany drawings in the above, it should be understood by those skilled in the art that the above detailed descriptions are only exemplary and for illustrative purpose, but not to limit the protection scope of the present invention. Taught by the present invention, those skilled in the art may make diverse variations, modifications or substitutions to the above-described embodiments according to specific situations without departing from the protection scope of the present invention. These variations, modifications or substitutions fall within the protection scope of the present invention.