Injection needle assembly

Abstract

A needle base of a needle comprises a lower section and an upper section, a shaft shoulder is arranged at the joint of the upper section and the lower section, the upper section is provided with rib plates connected to the shaft shoulder, a plurality of rib plates are distributed on the upper section in the circumferential direction, and spaced recesses are formed in the upper section through the adjacent rib plates. A rib mechanism is arranged on the inner cylinder wall of the sleeving opening part of the sheath, the rib mechanism comprises four long convex ribs and short convex ribs which are sequentially and alternately arranged in the sheath at intervals, the long convex ribs and the short convex ribs are all stopped with the rib plate, the front cut-off ends of the short convex ribs are inserted into the interval recesses and are stopped with the shaft shoulder, and the sleeving end parts of the long convex ribs comprise rear section parts and front section parts; the rear section part is higher than the front section part, a limiting end face in stopping fit with the shaft shoulder is formed at the end of the rear section part, the rear section part is inserted into the interval recess in a matched mode and is in positioning fit with the outer circumferential face of the upper section, and the front section part crosses the shaft shoulder and is in positioning fit with the outer circumferential face of the lower section. The assembly operation of the sheath and the needle seat is simple, convenient and reliable.

Description

Technical Field

[0001] The utility model relates to a medical device, specifically to a needle and its sheath for a syringe. Background Art

[0002] When the injection needle leaves the factory, a sheath covering the puncture needle tube is sleeved on the needle hub to prevent the puncture needle tube from being exposed, so as to protect the puncture needle tube and the operator. As Figure 1 shown, the structure of an existing injection needle assembly with a sheath is as follows: it includes a needle 1 and a sheath 2. The needle includes a needle hub 11 and a puncture needle tube 12. The sheath 2 has a socket part corresponding to the tube orifice position. The socket part includes engaging ribs 2-1 protruding on the annular inner cylinder wall. There are 4 equally high engaging ribs 22-1 distributed circumferentially along the inner cylinder wall. The outer circumferential surface of the needle hub 11 is in the shape of a multi-stage stepped shaft with a gradually increasing diameter from bottom to top. The upper section 112 of the needle hub 11 is connected to the lower section 111 through a shoulder. The end of the lower section of the needle hub is provided with a threaded structure for screwing onto the injection syringe barrel. Rib plates 1121 protrude on the cylindrical surface of the upper section of the needle hub. There are 4 rib plates distributed at equal intervals circumferentially on the upper section. The ends of the rib plates are integrally formed on the shoulder. Then, an interval depression is formed between adjacent rib plates. When the sheath is sleeved on the needle hub, the end of the engaging rib is placed in the interval depression, the clamping point of the engaging rib is stuck on the wall of the interval depression, and the end of the engaging rib abuts against the shoulder surface to realize the axial limit of the sheath. The side of the engaging rib is blocked by the rib plate to realize the circumferential linkage; a number of protrusions are densely distributed circumferentially on the outer circumferential surface of the sheath, so that an uneven surface is formed on the outer circumferential surface of the sheath to facilitate gripping.

[0003] Due to the small volume of the injection needle, especially for the needle for small-dose injection, in the existing structure of the needle assembly, during the assembly process of the sheath and the needle by equipment, the sheath is prone to skew and the sheath breaks through the limit of the shoulder part of the needle hub, and the sheath presses against the puncture needle tube, resulting in defective products, so that the defective rate of products during the production process is not ideal.

[0004] Meanwhile, in the feedback of the usage of the needle assembly, during the process of disassembling and assembling the needle by relying on the sheath, when directly pinching the sheath to screw the needle, the phenomenon of the sheath slipping on the needle base will occur. Since the size of the needle base of the existing needle can provide a part for the operator to pinch, the operator usually pinches the combined part of the sheath and the needle base to directly apply force on the needle base to complete the disassembly and assembly of the needle. Especially during the disassembly process of the injection needle, the above phenomenon is more obvious. The reason is that when the medical staff puts the sheath back on the needle base again, the sheath is prone to skew on the needle base, thus increasing the probability of the sheath slipping relative to the needle base. In view of the actual application process when the needle leaves the factory, we still hope to use the sheath to attach the injection needle to the syringe or remove it from the syringe, and to ensure the yield rate of the combined packaging production of the needle and the sheath. Improving the sheath and the needle base is an important topic that needs to be studied here. Summary of the Invention

[0005] The invention purpose of the present utility model: To overcome the defects existing in the prior art, the present utility model provides an injection needle assembly with simple assembly and disassembly operation of the sheath and the needle base and reliable screwing and unscrewing of the needle by pinching the sheath.

[0006] To achieve the above purpose, the present utility model provides the following technical solutions:

[0007] An injection needle assembly includes a needle and a sheath. The needle includes a needle base having a cavity for inserting a syringe nipple. The needle base includes a lower section and an upper section. A puncture needle tube communicating with the cavity is fixedly provided on the upper section. There is a shoulder at the junction of the upper section and the lower section. The upper section has rib plates formed on the outer cylindrical surface and connected to the shoulder. A plurality of rib plates are circumferentially distributed on the upper section, and spaced depressions are formed on the upper section by adjacent rib plates. The sheath includes a main sleeve body, and a socket opening part extends from the open end of the main sleeve body. A rib mechanism for sleeving the sheath on the needle base is provided on the inner cylindrical wall of the socket opening part of the sheath. It is characterized in that: the rib mechanism includes a short convex rib and a long convex rib that protrude radially. The front end of the short convex rib facing the opening of the sheath is the front cut-off end. The front cut-off end of the short convex rib can be inserted into the spaced depression and cooperate with the shoulder in a stop manner. The front end of the long convex rib is longer than that of the short convex rib. The long convex rib and the short convex rib are alternately arranged at intervals along the circumferential direction of the sheath. At least three short convex ribs and three long convex ribs are evenly spaced along the circumferential direction on the inner cylindrical wall of the sheath. Spaced depressions corresponding to the short convex ribs and the long convex ribs one by one are provided on the upper section. The front cut-off end of the short convex rib cooperates with the shoulder in a stop manner, and the short convex rib cooperates with the rib plate in a stop manner. And the long convex rib has a stepped socket end portion, which sequentially includes a rear section portion and a front section portion from the inner side of the sheath to the outer side port direction. The rear section portion is higher than the front section portion and a limiting end face is formed at the end of the rear section portion. The rear section portion is inserted into the spaced depression and is positioned and cooperated with the outer circumferential surface of the upper section. The rear section portion cooperates with the rib plate in a stop manner, and the limiting end face cooperates with the shoulder in a stop manner. The front section portion passes over the shoulder and is positioned and cooperated with the outer circumferential surface of the lower section.

[0008] Further, the depth of the cavity on the needle base is 6.6 - 6.7 mm.

[0009] Further, the outer circumferential surface of the main sleeve body of the sheath is a wavy cylindrical surface with alternating convex and concave portions along the circumferential direction, so that convex ribs are spacedly arranged on the outer circumferential surface of the main sleeve body, and grooves are formed between two convex ribs. The two side walls of the groove are in a slope shape from bottom to top, so that the convex ribs are larger at the bottom and smaller at the top.

[0010] Further, the wall of the groove is concave-arc-shaped.

[0011] Further, both the long convex rib and the short convex rib are four in number.

[0012] The utility model has the following technical effects: 1. By adopting at least three convex ribs with different lengths, the number of convex ribs is increased, so that the strength of the socket opening part of the sheath is increased, the sheath is not easily deformed, and the reliability of the stop matching points between the sheath and the needle seat in the rotation direction and the axial direction is improved; 2. The number of stop matching points between the sheath and the needle seat in the rotation direction and the axial direction is increased, so that the anti-rotation in the rotation direction and the axial limit between the sheath and the needle seat are reliable; 3. The front section and the rear section of the long convex rib are both positioned and matched with the needle seat to form two matching points on the same straight line, which can better ensure the central positioning of the sheath and the needle seat and prevent the sheath from skewing; the front section of the long convex rib forms a guide for the sheath to be sleeved on the needle seat to improve the reliability of the assembly of the sheath and the needle seat; 4. By arranging the long convex rib and the short convex rib, the long convex rib plays a guiding role and is combined with the short convex rib design, which can ensure the angular space for the assembly of the sheath and the needle head, make the assembly of the sheath and the needle head stable and reliable, and reduce the rejection rate. 5. The cavity on the needle head is designed with the limit size under the production standard, which not only ensures the production standard of the needle head to meet the matching requirements between the needle head and the syringe, but also reduces the volume of the cavity to realize the low residual design of the liquid medicine in the needle head; at the same time, after the needle head is shortened, although the length of the needle head protruding from the sheath is shortened and an effective holding part cannot be formed, under the above sheath structure, it can be ensured that the needle head can be reliably driven by the sheath to rotate, and the needle head can be screwed and disassembled by using the sheath; therefore, under the design of the sheath, the needle head can achieve the reduction of the liquid medicine residue in the needle head by shortening the needle head cavity (and the size of the injection needle head is shortened), and the liquid medicine low residual design can be achieved by a relatively simple structure design of the needle head. 6. The outer circumferential surface of the main body of the sheath adopts a special concave-convex design, which not only increases the hand feeling of holding the sheath, makes the screwing operation of the sheath more stable and reliable, but also under the shape structure of the convex rib, similar to the "triangle" shape, can make the sheath not easily deformed during molding and ensure the coaxiality of the sheath.

[0013] The following further describes the present utility model with reference to the accompanying drawings. Description of the Drawings

[0014] Figure 1 is the disassembled state diagram of the existing injection needle assembly of the present utility model;

[0015] Figure 2 is the bottom view of the injection needle assembly of the present utility model;

[0016] Figure 3 is Figure 2 the cross-sectional view taken along the section A-A in

[0017] Figure 4 is Figure 2 the cross-sectional view taken along the section B-B in

[0018] Figure 5 is the structural schematic diagram of the sheath of the present utility model;

[0019] Figure 6 is Figure 5 a sectional view taken along C-C in

[0020] Figure 7 a schematic structural view of the needle of the present utility model;

[0021] Figure 8 is Figure 7 a sectional view taken along D-D in

[0022] Figure 9 a disassembled state view of the injection needle assembly of the present utility model;

[0023] Needle 1, needle seat 11, cavity 110, lower section 111, upper section 112, spaced recess 1120, anti-disengagement bottom wall 11201, rib plate 1121, shoulder 113, sheath 2, main sleeve body 21, convex rib 211, groove 212, wall 2121, socket opening 22, short convex rib 221, front cut-off end 2211, long convex rib 222, rear section 2221, limiting end face 22211, clamping point 22212, front section 2222. Specific embodiments

[0024] See the attached Figures 2 - 8, an injection needle assembly disclosed by the present utility model includes a needle 1 and a sheath 2. The needle 1 includes a needle seat 11 having a cavity 110 for inserting the nipple of a syringe. The needle seat 11 includes a lower section 111 and an upper section 112. A puncture needle tube 12 communicating with the cavity 110 is fixedly provided on the upper section 112. There is a shoulder 113 at the junction of the upper section 112 and the lower section 111. The upper section 112 has rib plates 1121 formed on the outer cylindrical surface and connected to the shoulder 113. A plurality of rib plates 1121 are circumferentially distributed on the upper section 112. Adjacent rib plates 1121 form spaced depressions 1120 on the upper section. The number of rib plates 1121 is 8, thus forming 8 spaced depressions 1120. The sheath 2 includes a main sleeve body 21. A socket opening part 22 extends from the open end of the main sleeve body 21. On the inner wall of the socket opening part 22 of the sheath 2, there is a rib mechanism for sleeving the sheath 2 on the needle seat 1. The rib mechanism includes a radially protruding short rib 221 and a long rib 222. The front cut-off end of the short rib 221 facing the opening of the sheath is 2211. The front cut-off end 2211 of the short rib 21 can be inserted into the spaced depression 1120 and is in stop cooperation with the shoulder 113. The front end of the long rib 222 is longer than that of the short rib 221. The long rib 222 and the short rib 221 are alternately arranged at intervals along the circumferential direction of the sheath 2. At least three short ribs 221 and three long ribs 222 are evenly distributed at intervals along the circumferential direction on the inner wall of the sheath 2. In this specific embodiment, both the long rib 222 and the short rib 221 are four. On the upper section 112, there are spaced depressions 1120 corresponding to and cooperating with the short rib 221 and the long rib 222 one by one. The short rib 221 is in stop cooperation with the rib plate 1121. And the long rib 222 has a stepped socket end. This socket end includes a rear section 2221 and a front section 2222 in sequence from the inner side of the sheath 2 to the outer side port direction. The rear section 2221 is higher than the front section 2222 and a limiting end face 22211 is formed at the end of the rear section 2221. The rear section 2221 is inserted into the spaced depression 1120 and is in positioning cooperation with the outer circumferential surface of the upper section 112. The rear section 2221 is in stop cooperation with the rib plate 1121. The limiting end face 22211 is in stop cooperation with the shoulder 113. The front section 2222 passes over the shoulder 113 and is in positioning cooperation with the outer circumferential surface of the lower section 111. To achieve better performance of preventing the sheath from disengaging from the needle seat, usually the spaced depression 1120 has a raised ramp-shaped anti-disengagement bottom wall 11201, that is, the outer circumferential surface of the upper section 112 has a ramp-shaped wall, and this wall constitutes the ramp-shaped anti-disengagement bottom wall. The ramp-shaped anti-disengagement bottom wall gradually raises from the end near the shoulder 113 to the other end. A raised clamping point 22212 is provided on the rear section 2221. The clamping points of each rear section 2221 surround and form a positioning hole cavity on the upper section 112. In this way, the clamping points on the rear section 2221 are clamped into the spaced depression and pushed to the position near the shoulder. The clamping points are stopped by the ramp-shaped anti-disengagement bottom wall to achieve a more reliable performance of preventing the sheath from being pulled off.Under this design, the rib mechanism of the sheath 2 not only increases the number of ribs (the total number of the long ribs 222 and the short ribs 221 is greater than the total number of ribs on the original sheath - as shown in... Figure 1 ), which strengthens the strength of the socket opening 22 of the sheath 2, making the sheath 2 not easily deformed, so that the mating points on the sheath 2 that cooperate with the needle seat 11 are maintained in stable positions; and the number of mating points increases, thereby improving the stability of the sheath in both axial limit and rotational direction stop limit; at the same time, the long rib design is introduced. The long rib 222 has a stepped socket end. There are two mating positions on a single long rib 222, which can better ensure the central positioning of the sheath and the needle seat 11, prevent the sheath 2 from skewing when sleeved on the needle tip, avoid the slipping phenomenon caused by the skewing of the sheath, and reduce or eliminate the risk of damage to the puncture needle tube caused by the skewing of the sheath, improving the yield rate during product packaging and assembly. The stepped socket end of the long rib 222 has a relatively large socket hole formed by the front sections of each long rib 222. During the operation of sleeving the sheath on the needle seat 11, it plays a guiding role, enabling the sheath to be more reliably sleeved onto the needle seat 11. The long rib is configured with a short rib design, which while increasing the number of ribs, ensures the angular space for the assembly of the sheath and the needle, reducing the rejection rate. Since the injection needle has a small volume and the above-mentioned sheath has a simple structure, it has the advantage of being convenient for processing and forming.

[0025] Under the above sheath design, it is possible to drive the needle tip to rotate by the sheath to complete the disassembly and assembly operation of the needle tip. Furthermore, the following optimized design is adopted. The depth L of the cavity 110 on the needle seat 11 is set to 6.6 - 6.7 mm. On the basis of meeting the production size standard of the needle tip and the matching requirements between the needle tip and the syringe, at the same time, the volume of the cavity is reduced to achieve the design of low residual liquid in the needle tip, and a relatively simple structure design of the needle tip is used to achieve the design of low residual liquid.

[0026] Furthermore, the outer circumferential surface of the main sleeve body 21 of the sheath 2 is a wavy cylindrical surface with alternating concave and convex distributions along the circumferential direction, thereby forming spaced-apart convex ribs 211 and grooves 212 located between two convex ribs 211 on the outer circumferential surface of the main sleeve body 21. The two side walls 2121 of the groove 212 are in a slope shape from bottom to top, and thus the convex rib 211 has a larger bottom and a smaller top. The wall of the groove 212 is in a concave arc shape. The special concave and convex design of the outer circumferential surface of the main sleeve of the sheath not only increases the hand feeling of holding the sheath, making the screwing operation of the sheath more stable and reliable, but also under the shape structure of the convex rib, similar to a "triangle" shape, it can make the sheath not easily deformed during molding, ensure the coaxiality of the sheath, and improve the yield rate of the product.

[0027] The improved sheath introduced the matching structure of long ribs and short ribs. First, it increased the matching points and the strength of the sheath, thereby improving the reliability of the fit between the sheath and the needle hub. Second, it enhanced the reliability of the central positioning of the socket fit between the sheath and the needle hub, avoided the skew of the sheath, and improved the reliability of the fit between the sheath and the needle hub. This not only increased the yield rate in the production and packaging processes of the sheath and the needle hub, but also ensured the stability and reliability of the sheath socket operation by medical staff during use. Third, the long ribs achieved the guiding of the sheath when it was sleeved on the needle hub. The cooperation between the long ribs and the short ribs ensured the angular space for the assembly of the sheath and the needle, enabling the sheath to be smoothly and reliably sleeved on the needle hub, reducing the rejection rate and improving the convenience of sleeving the sheath on the needle hub. Moreover, due to the small volume of the injection needle and the sheath, the above improved structure is simple, easy to implement and popularize.

[0028] The depth of the upper cavity on the needle hub of the needle is controlled within a specific size specification. Under this size specification, it meets the dimensional standard requirements of the needle, ensures the need for the needle to match with syringes on the market, reduces the cavity volume and the residual amount of liquid medicine on the needle, realizes the low-residue design of the injection needle, and this low-residue design is achieved by controlling the size, which is easy to implement and has a low cost. For such consumables as injection needles that are used in large quantities, it has greater market advantages. When the depth of the upper cavity on the needle hub is reduced, the size of the needle hub will be shortened, and the part of the needle hub that can be held by hand is insufficient. On the basis of the above improved design, it is realized that the needle can be reliably driven to rotate by relying on the sheath, meeting the use operation of the improved low-residue injection needle.

[0029] The main part of the sheath adopts a special wavy design to improve the overall strength of the sheath, thereby ensuring the coaxiality during the overall molding of the sheath, further guaranteeing the reliability of the fit between the sheath and the needle hub, and avoiding the risk of damaging the puncture needle tube when the sheath is sleeved on the needle hub. Moreover, this design effectively improves the hand feeling when the sheath is held by hand, avoiding slipping between the hand and the sheath.

Claims

1. An injection needle assembly, comprising a needle and a sheath. The needle includes a needle hub having a cavity for inserting a syringe nipple. The needle hub includes a lower section and an upper section. A puncture needle tube communicating with the cavity is fixedly provided on the upper section. There is a shoulder at the junction of the upper section and the lower section. The upper section has rib plates formed on the outer cylindrical surface and connected to the shoulder. A plurality of rib plates are circumferentially distributed on the upper section, and spaced depressions are formed on the upper section by adjacent rib plates. The sheath includes a main sleeve body, and a socket opening is extended from the open end of the main sleeve body. A rib mechanism for sleeving the sheath on the needle hub is provided on the inner cylindrical wall of the socket opening of the sheath. It is characterized in that: The rib mechanism includes short ribs and long ribs that radially protrude. The front end of the short rib facing the opening of the sheath is the front cut-off end. The front cut-off end of the short rib can be inserted into the spaced recess and cooperate with the shoulder for stop. The front end of the long rib is longer than that of the short rib. The long ribs and short ribs are arranged alternately at intervals along the circumferential direction of the sheath in the sheath. At least three short ribs and three long ribs are evenly distributed at intervals along the circumferential direction on the inner cylindrical wall of the sheath. There are spaced recesses in the upper section that cooperate with the short ribs and long ribs one by one. The front cut-off end of the short rib cooperates with the shoulder for stop. The short rib cooperates with the rib plate for stop. The long rib has a stepped socket end portion, which successively includes a rear section portion and a front section portion from the inner side of the sheath to the outer side port direction. The rear section portion is higher than the front section portion and a limiting end face is formed at the end of the rear section portion. The rear section portion is inserted into the spaced recess and is positioned and cooperated with the outer circumferential surface of the upper section. The rear section portion cooperates with the rib plate for stop. The limiting end face cooperates with the shoulder for stop. The front section portion passes over the shoulder and is positioned and cooperated with the outer circumferential surface of the lower section.

2. The injection needle assembly according to claim 1, wherein: The depth of the cavity on the needle seat is 6.6 - 6.7 mm.

3. The injection needle assembly according to claim 1, wherein: The outer circumferential surface of the main sheath body of the sheath is a wavy cylindrical surface with alternating concave and convex portions along the circumferential direction, so that convex ribs arranged at intervals and grooves located between two convex ribs are formed on the outer circumferential surface of the main sheath body. The two side walls of the groove are in a slope shape from bottom to top, and further make the convex rib have a larger bottom and a smaller top.

4. The injection needle assembly according to claim 3, wherein: The wall of the groove is concave arc-shaped.

5. The injection needle assembly according to claim 1, characterized in that: Both the long rib and the short rib are four in number.

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