A needle-stick prevention device with elastic collar and stopper

Abstract

An elastic collar and a stopper cooperated needle puncture prevention device comprises: a catheter seat assembly, the rear end of which is provided with an anti-slip structure; a needle shield, which is provided with a needle through hole, a slide groove, and a slot; an elastic collar, which is sleeved on the needle shield; a stopper, which is slidably installed in the slide groove, one side of which cooperates with the needle tube, and the other side is supported on the inner wall of the elastic collar; a limit plate, which is installed in the slot and is provided with a stop hole; a needle seat, which sleeves the rear part of the needle shield; the needle tube, which passes through the catheter seat assembly, the needle shield, and the limit plate, and provides support for the stopper, and the rear end of the needle seat is fixed in the needle seat, and a protruding buckle is provided near the front end. Pull the needle seat backward to make the needle seat drive the needle tube to retreat, and when the needle tube retreats to the point where the protruding buckle is blocked by the stop hole of the limit plate, the front end of the needle tube retreats away from the stopper, and the stopper slides into the slide groove of the needle shield under the action of the elastic collar, thereby blocking the front end of the needle tube, and the needle tip is shielded in the needle shield, thereby improving the safety of the product.

Description

Technical Field

[0001] The invention relates to the technical field of needle protection, and in particular to an elastic sleeve ring and a stopper matching type needle puncture prevention device. Background Art

[0002] After the existing products with needle tubes are pulled out after use, the needle tip of the needle tube is often exposed to the outside, which can easily cause punctures to people. This is especially true for medical needle products, where the safety hazard is more serious. Once a used medical needle product causes a puncture to a person, there is a possibility of cross infection. Summary of the invention

[0003] In view of the above problems, the present invention provides a needle-puncture prevention device which is a combination of an elastic collar and a stopper.

[0004] The purpose of the present invention can be achieved by the following technical solutions:

[0005] An elastic collar and a stopper-matched needle-puncture prevention device, comprising:

[0006] The catheter seat assembly has an anti-drop structure at its rear end;

[0007] A needle protection sleeve, which is provided with a needle through hole extending along the axis, the front part of which is inserted from the rear end of the catheter seat assembly, the front end of the outer wall of which is provided with a slide groove, the slide groove divides the front end of the needle through hole into two sections, and the rear end of the outer wall of which is provided with a slot, the slot divides the rear end of the needle through hole into two sections;

[0008] An elastic collar is sleeved on the front end of the outer wall of the needle protection sleeve through elastic deformation and corresponds to the position of the slide groove;

[0009] The stopper is slidably mounted in the slide groove of the needle shield, and one side of the stopper facing the inside of the slide groove of the needle shield cooperates with the needle tube, and the other side of the stopper facing the outside of the slide groove of the needle shield is supported on the inner wall of the elastic collar, and the rear part of the stopper cooperates with the anti-drop structure of the catheter seat assembly;

[0010] A stopper is installed in the slot of the needle protection sleeve and is provided with a stopper hole corresponding to the needle through hole;

[0011] A needle seat, covering the rear portion of the needle guard;

[0012] The needle tube passes through the catheter seat assembly, the needle through hole of the needle protective sleeve, and the stop hole of the limit plate, and provides support for the stopper. Its rear end is fixed in the needle seat, and a protruding buckle with a size larger than the stop hole of the limit plate is provided near the front end of its outer wall;

[0013] The needle seat is pulled backward, driving the needle tube to retreat axially together. When the needle tube retreats to the point where the raised buckle is blocked by the stop hole of the limit plate, the front end of the needle tube retreats and leaves the block. The block loses the support of the needle tube, and under the elastic restoring force of the elastic ring, the block is separated from the anti-detachment structure of the catheter seat assembly and slides into the inside of the slide groove of the needle guard sleeve, so that the block blocks the front end of the needle through hole of the needle guard sleeve to prevent the front end of the needle tube from extending forward. The needle guard sleeve, the block and the limit plate shield the front end of the needle tube, and the needle seat continues to be pulled backward, driving the limit plate through the raised buckle of the needle tube, and then driving the needle guard sleeve and the elastic ring and the block thereon to move backward together. When the needle guard sleeve is pulled out from the rear end of the catheter seat assembly, it is separated from the catheter seat assembly.

[0014] The structure of the stopper may adopt the following two schemes.

[0015] In one solution, the anti-drop structure of the catheter seat assembly is a circumferentially inwardly concave annular groove at the rear end of the inner wall of the catheter seat, and the rear side of the stopper is provided with a stop protrusion that matches the annular groove of the catheter seat.

[0016] Another solution is that the anti-drop structure of the catheter seat assembly is a slot penetrating the side wall of the catheter seat, and the back side of the other side of the stopper is provided with a stop protrusion that matches the slot of the catheter seat. Furthermore, positioning ribs that match the slide groove of the needle shield can be provided on both sides of the stopper.

[0017] To further refine the above technical solution, the other side of the stopper may be provided with a positioning groove for the elastic ring to be inserted into. The front side, the rear side and both sides of the stopper may be provided with positioning surfaces that match the sliding groove of the needle protection sleeve.

[0018] An annular positioning groove which is concave in the circumferential direction is provided at the front end of the outer wall of the needle protection sleeve. A positioning plane which is parallel to the axis is provided on the bottom surface of the annular positioning groove. A sliding groove is provided on the positioning plane. Both the sliding groove and the slot are arranged along the radial surface. The elastic ring is sleeved in the annular positioning groove by elastic deformation.

[0019] The limiting piece can be in an L-shaped sheet shape, one side of the limiting piece is installed in the slot of the needle protection sleeve and is provided with a stop hole, and the other side of the limiting piece is arranged on the outer wall of the needle protection sleeve. The edge of the stop hole of the limiting piece is provided with a flange.

[0020] A groove connected to the inner hole is provided at the front end of the needle tube, and a side of the block that cooperates with the needle tube can adopt an arc transition with the front side surface. When the needle tube retreats and passes through the block, one side of the block is tightly attached to the outer wall of the needle tube under the elastic restoring force of the elastic ring and is located outside the groove of the needle tube, so that the needle tube retreats smoothly.

[0021] Compared with the prior art, the present invention has the following beneficial effects: the overall structure is compact and the operation is simple. The needle seat is pulled backward to make the needle seat drive the needle tube to retreat axially. When the needle tube retreats to the point where the protruding buckle is blocked by the stop hole of the limiting plate, the front end of the needle tube retreats and leaves the block. The block loses the support of the needle tube and slides into the slide groove of the needle shield under the elastic restoring force of the elastic ring, thereby blocking the front end of the needle through hole of the needle shield and preventing the front end of the needle tube from extending forward, thereby shielding the front end needle tip of the needle tube inside the needle shield, thereby improving the safety of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the decomposition structure of Example 1.

[0023] Figure 2 This is a full cross-sectional view of Example 1.

[0024] Figure 3 Schematic diagram of the structure of the catheter seat assembly in Example 1.

[0025] Figure 4 It is a schematic diagram of the assembly of the needle protection sleeve, elastic collar, stopper, limiting plate and needle tube in Example 1.

[0026] Figure 5 This is a schematic diagram of the structure of the needle protection sleeve in Example 1.

[0027] Figure 6 This is a schematic diagram of the structure of the stopper in Example 1.

[0028] Figure 7 This is a partial cross-sectional view of Example 1.

[0029] Figure 8 This is a schematic diagram of the structure of the limiting piece in Example 1.

[0030] Fig. 9 This is a schematic diagram of the structure of the needle seat and needle tube in Example 1.

[0031] Fig.10 It is a partial cross-sectional view of Example 1 entering the self-destruct state.

[0032] Fig.11 It is a schematic diagram of the structure of embodiment 1 after entering the self-destruct state and being separated from the catheter seat assembly.

[0033] Fig.12 This is a schematic diagram of the process of the groove of the needle tube passing through the block in Example 1.

[0034] Figures 1 to 12 The parts are numbered as follows:

[0035] 1 catheter seat assembly, 101 catheter seat, 1011 annular groove, 102 metal wedge, 103 catheter, 104 isolation plug;

[0036] 2 needle protection sleeve, 201 needle through hole, 202 annular positioning groove, 203 positioning plane, 204 slide groove, 205 slot, 206 groove, 207 concave table;

[0037] 3 elastic collar;

[0038] 4 stopper, 401 positioning groove, 402 positioning surface, 403 stop protrusion, 404 arc;

[0039] 5 limit pieces, 501 stop holes;

[0040] 6 needle seat, 601 seat body, 602 handle;

[0041] 7 needle tube, 701 raised buckle, 702 groove.

[0042] Fig.13 This is a schematic diagram of the decomposition structure of Example 2.

[0043] Fig.14 This is a full cross-sectional view of Example 2.

[0044] Fig.15 Schematic diagram of the structure of the catheter seat assembly in Example 2.

[0045] Fig.16 This is a schematic diagram of the assembly of the needle shield, elastic collar, stopper, limiting plate, and needle tube in Example 2.

[0046] Fig.17 This is a schematic diagram of the structure of the needle protection sleeve in Example 2.

[0047] Fig.18 This is a schematic diagram of the structure of the stopper in Example 2.

[0048] Fig.19 This is a partial cross-sectional view of Example 2.

[0049] Fig. 20 This is a schematic diagram of the structure of the limiting plate in Example 2.

[0050] Fig.21 It is a partial cross-sectional view of Example 2 entering the self-destruct state.

[0051] Fig. 22 This is a schematic diagram of the structure of Example 2 after entering the self-destruct state and separating from the catheter seat assembly.

[0052] Figures 13 to 22 The numbers of the catheter seat, stopper and limit plate are as follows, and the numbers of the other parts refer to Figures 1 to 12 :

[0053] 101 catheter seat, 1011 card slot;

[0054] 4 stopper, 401 positioning groove, 402 positioning surface, 403 stop protrusion, 404 arc, 405 positioning convex rib;

[0055] 5 limiting piece, 501 stop hole, 502 flange. DETAILED DESCRIPTION

[0056] The specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that those skilled in the art can more clearly understand how to practice the present invention. Although the present invention is described in conjunction with its preferred specific embodiments, these embodiments are only illustrative, rather than limiting the scope of the present invention.

[0057] Example 1

[0058] See also Figure 1 and Figure 2 A needle-stick prevention device with an elastic collar and a stopper comprises a catheter seat assembly 1, a needle protection sleeve 2, an elastic collar 3, a stopper 4, a limiting piece 5, a needle seat 6, and a needle tube 7.

[0059] See also Figure 2 and Figure 3 The catheter seat assembly 1 includes a catheter seat 101, a metal wedge 102, a catheter 103, and an isolation plug 104. The metal wedge 102 and the isolation plug 104 are installed in the catheter seat 101 in a front-to-back arrangement. The catheter 103 extends from the front end of the catheter seat 101, and its rear end is fixed to the metal wedge 102. An anti-slip structure is provided at the rear end of the inner wall of the catheter seat 101, which is used to cooperate with the stop protrusion 403 of the stopper 4 to ensure that the needle shield 2 is connected to the catheter seat 101, see Figure 2 The anti-drop structure is an annular groove 1011 which is circumferentially concave at the rear end of the inner wall of the catheter seat 101 .

[0060] See also Figure 2 The front portion of the needle shield 2 is inserted into the catheter adapter 101 from the rear end of the catheter adapter 101. Figure 4 and Figure 5The needle protection sleeve 2 is cylindrical, and a needle through hole 201 is provided in the needle protection sleeve 2 along the axis. A ring-shaped positioning groove 202 is arranged along the circumferential direction at the front end of the outer wall of the needle protection sleeve 2, and the ring-shaped positioning groove 202 is used to install the elastic collar 3. The front and rear groove walls of the ring-shaped positioning groove 202 block the elastic collar 3 to prevent its axial movement. The bottom surface of the ring-shaped positioning groove 202 is provided with a positioning plane 203 parallel to the axis of the needle protection sleeve 2, and the distance from the positioning plane 203 to the axis of the needle protection sleeve 2 is less than the groove bottom radius of the ring-shaped positioning groove 202. A slide groove 204 is provided on the positioning plane 203 along the radial surface of the needle protection sleeve 2, and the width of the slide groove 204 is greater than the width of the ring-shaped positioning groove 202 and extends beyond the front and rear groove walls of the ring-shaped positioning groove 202. The slide groove 204 divides the front end of the needle through hole 201 into two sections, and the slide groove 204 is used to install the stopper 4. A slot 205 arranged along a radial surface is provided at the rear end of the outer wall of the needle protection sleeve 2 , and the slot 205 divides the rear end of the needle through hole 201 into two sections. The slot 205 is used to install the limiting piece 5 .

[0061] See also Figure 4 and Figure 7 The elastic collar 3 is sleeved in the annular positioning groove 202 of the needle protection sleeve 2 by elastic deformation, and the inner diameter of the elastic collar 3 is smaller than the bottom diameter of the annular positioning groove 202 .

[0062] See also Figure 4 , Figure 6 and Figure 7 The stopper 4 is installed in the slide groove 204 of the needle protection sleeve 2 and can slide in the vertical direction of the positioning plane 203. The side of the stopper 4 facing the slide groove 204 cooperates with the needle tube 7. The other side of the stopper 4 facing the outside of the slide groove 204 is supported on the inner wall of the elastic collar 3 and is provided with a positioning groove 401 for the elastic collar 3 to be inserted. The front side, rear side and both sides of the stopper 4 are provided with positioning surfaces 402 that cooperate with the slide groove 204. The rear side of the stopper 4 is provided with a stop protrusion 403 that cooperates with the annular groove 1011 of the catheter seat 101. The front end of the outer wall of the needle protection sleeve 2 is also provided with a groove 206 corresponding to the stop protrusion 403. Figure 5 , the groove 206 is connected to the rear side of the slide groove 204.

[0063] See also Figure 4 and Figure 8 The stopper 5 is in an L-shaped sheet shape, one side of the stopper 5 is interference-fitted into the slot 205 of the needle shield 2 and is provided with a stopper hole 501 corresponding to the needle through hole 201 of the needle shield 2. The rear end of the outer wall of the needle shield 2 is also provided with a concave table 207 which is parallel to the axis of the needle shield 2 and is concave inward. Figure 5The concave table 207 is arranged corresponding to the notch of the slot 205 to facilitate the assembly and disassembly of the limiting piece 5 , and the other side of the limiting piece 5 is arranged on the concave table 207 of the needle protection sleeve 2 .

[0064] See also Figure 2 and Fig. 9 The needle seat 6 includes a seat body 601 and a handle portion 602. The seat body 601 is provided with an inner hole and a needle fixing hole connected front and back along the axis. The seat body 601 covers the rear part of the needle protection sleeve 2 through the inner hole, and its front end face is against the rear end face of the catheter seat 101. The needle fixing hole is used to fix the rear end of the needle tube 7. The handle portion 602 is connected to the side of the seat body 601. The needle tube 7 passes through the inner hole of the catheter 103, the inner hole of the metal wedge 102, the isolation plug 104, the needle through hole 201 of the needle protective sleeve 2, and the stop hole 501 of the limiting plate 5, and provides support for the stopper 4. The front end of the needle tube 7 is a needle tip and is exposed from the front end of the catheter 103. The rear end of the needle tube 7 is fixed in the needle fixing hole of the seat body 601 fixed to the needle seat 6. A protruding buckle 701 protruding along the circumferential direction is provided on the outer wall of the needle tube 7 near the front end. The outer diameter of the protruding buckle 701 is larger than the stop hole 501 of the limiting plate 5, and smaller than the inner hole of the catheter 103, the inner hole of the metal wedge 102, and the needle through hole 201 of the needle protective sleeve 2. In addition, the axial distance between the protruding buckle 701 and the front end of the needle tube 7 is slightly smaller than the axial distance between the stopper 4 and the limiting plate 5.

[0065] During assembly, first install the block 4 into the slide groove 204 of the needle shield 2, install the stopper protrusion 403 of the block 4 into the groove 206, and install one side of the limit plate 5 into the slot 205 of the needle shield 2. Then, the rear end of the needle tube 7 is inserted from the front end of the needle through hole 201 of the needle shield 2, and then passes through the stopper hole 501 of the limit plate 5 backwards, and then extends from the rear end of the needle through hole 201 of the needle shield 2. Next, the rear end of the needle tube 7 is inserted into the needle fixing hole after passing through the inner hole of the needle seat 6, and fixed by environmentally friendly quick-drying glue. Then, the rear part of the needle shield 2 is installed into the inner hole of the seat body 601 of the needle seat 6, and the rear end surface of the needle shield 2 is against the bottom surface of the inner hole of the seat body 601, and the elastic ring 3 is simultaneously or successively sleeved in the annular positioning groove 202 of the needle shield 2 and the positioning groove 401 of the block 4. After that, the front end of the needle tube 7 is inserted into the catheter seat assembly 1, which is an assembled complete set of components. The front end of the needle tube 7 is inserted from the rear end of the catheter seat 101, and then passes through the isolation plug 104 and the metal wedge 102 in sequence to the catheter 103. Finally, the front part of the needle shield 2 is installed into the catheter seat 101 from the rear end of the catheter seat 101, so that the front end surface of the seat body 601 of the needle seat 6 is against the rear end surface of the catheter seat 101. At this time, the needle tip of the needle tube 7 is exposed from the front end of the catheter 103, and the exposed length of the needle tip meets the standard requirements. The stop protrusion 403 of the stopper 4 is set in the annular groove 1011 of the catheter seat 101 and is axially limited, so that the needle shield 2 maintains a good connection with the catheter seat 101 without external force. At this point, the assembly of the anti-needlestick device is completed, and the anti-needlestick device is in an unused state.

[0066] When the needle stick prevention device is used clinically for puncture, the handle 602 of the hand-held needle holder 6 drives the needle holder 6 and the needle tube 7 to move backward. Fig.10 When the needle tube 7 retreats to the point where the protruding buckle 701 is blocked by the stopping hole 501 of the limiting plate 5, the front end of the needle tube 7 retreats away from the stop block 4, and the stop block 4 loses the support of the needle tube 7. Under the elastic restoring force of the elastic ring 3, the stop protrusion 403 of the stop block 4 is disengaged from the annular groove 1011 of the catheter seat 101, and the stop block 4 slides toward the inside of the slide groove 204 of the needle protection sleeve 2 along the vertical direction of the positioning plane 203, thereby blocking the front end of the needle through hole 201 of the needle protection sleeve 2 to prevent the front end of the needle tube 7 from extending forward. At this time, the front end of the needle tube 7 is shielded in the needle protection sleeve 2 by the stop block 4 and the limiting plate 5, and the needle tube 7 and the needle protection sleeve 2 cannot move relative to each other along the axis, and the anti-needlestick device enters a self-destructive state. At the same time, since the stop protrusion 403 of the stopper 4 is disengaged from the annular groove 1011 of the catheter seat 101, the anti-detachment function between the stopper 4 and the catheter seat 101 fails, and the catheter seat assembly 1 can be separated as a whole.

[0067] See also Fig.11, continue to hold the handle portion 602 of the needle seat 6 to drive the needle seat 6 and the needle tube 7 to move backward, and drive the limiting plate 5 through the raised buckle 701 of the needle tube 7, and then drive the needle shield 2 and the elastic ring 3 and the stopper 4 thereon to move backward together. When the needle shield 2 is pulled out from the rear end of the catheter seat 101, it is separated from the catheter seat assembly 1.

[0068] It should be noted that, for the needle tube 7 with the groove 702 at the front end, it is necessary to consider the situation when the groove 702 of the needle tube 7 passes through the stopper 4 in an extreme case during the needle tube 7 retreating process. For the stopper 4 of this embodiment, since the stopper 4 is a block and the surface that matches the needle tube 7 is a whole surface structure, and the length of this surface is greater than the length of the groove 702 of the needle tube 7, the surface and the front side surface of the stopper 4 are transitioned by an arc 404, see Fig.12 When the groove 702 of the needle tube 7 retreats and passes through the stopper 4, most of the side of the stopper 4 that cooperates with the needle tube 7 is located on the surface of the needle tube 7, and under the action of the elastic ring 3, it is tightly attached to the needle tube 7 until the groove 702 of the needle tube 7 completely passes through the arc 404 of the stopper 4. The stopper 4 will not be stuck in the groove 702 of the needle tube 7. In this way, the needle tube 7 can be pulled out smoothly without any sense of frustration, which is convenient for clinical use.

[0069] Example 2

[0070] See also Fig.13 and Fig.14 A needle-stick prevention device with an elastic collar and a stopper comprises a catheter seat assembly 1, a needle protection sleeve 2, an elastic collar 3, a stopper 4, a limiting piece 5, a needle seat 6, and a needle tube 7.

[0071] See also Fig.14 and Fig.15 The catheter seat assembly 1 includes a catheter seat 101, a metal wedge 102, a catheter 103, and an isolation plug 104. The difference from Example 1 is that an anti-slip structure is provided at the rear end of the side wall of the catheter seat 101, and the anti-slip structure is a card slot 1011 that penetrates the side wall of the catheter seat 101 and is used to cooperate with the stop protrusion 403 of the stopper 4 to ensure that the needle shield 2 is connected to the catheter seat 101.

[0072] See also Fig.16 and Fig.17 The needle shield 2 is still provided with a needle through hole 201, an annular positioning groove 202, a positioning plane 203, a slide groove 204, and a slot 205, but the dimensions are slightly different from those in Example 1, which will not be described in detail.

[0073] See also Fig.16 , Fig.18 , Fig.19The difference between the stopper 4 and the embodiment 1 is that the back side of the other side of the stopper 4 facing the outside of the slide groove 204 is provided with a stopper protrusion 403 matching with the clamping groove 1011 of the catheter seat 101, and both sides of the stopper 4 are provided with positioning ribs 405 matching with the slide groove 204. The positioning groove 401, the positioning surface 402, and the arc 404 are only different in size and will not be described in detail.

[0074] See also Fig.16 and Fig. 20 The difference between the limiting plate 5 and the embodiment 1 is that a flange 502 arranged along the edge of the stop hole 501 is provided on one side of the limiting plate 5 to ensure that one side of the limiting plate 5 is installed in the slot 205 of the needle protection sleeve 2 with interference fit.

[0075] The elastic collar 3, needle seat 6 and needle tube 7 refer to Example 1.

[0076] See also Fig.14 The difference during assembly is that the seat body 601 of the needle seat 6 covers the needle shield 2 and the rear part of the catheter seat 101 through the inner hole, and the stop protrusion 403 of the stopper 4 is set in the groove 1011 of the catheter seat 101 and axially limited, so that the needle shield 2 maintains a good connection with the catheter seat 101 without external force. The assembly instructions of other components refer to Example 1.

[0077] See also Fig.21 The difference when the needle stick prevention device enters the self-destruction state is that when the block 4 without the support of the needle tube 7 slides into the slide groove 204 of the needle protection sleeve 2 under the elastic restoring force of the elastic ring 3, the stop protrusion 403 of the block 4 is disengaged from the card slot 1011 of the catheter seat 101, and the anti-detachment function between the block 4 and the catheter seat 101 fails, and the catheter seat assembly 1 can be separated as a whole. The final state of the catheter seat assembly 1 after separation is shown in FIG. Fig. 22 .

[0078] It should be noted that the fully described invention may also have a variety of variations and modifications, and is not limited to the specific embodiments described above. The above embodiments are merely illustrative of the invention, not limiting thereof. In short, the scope of protection of the invention should include those variations or substitutions and modifications that are obvious to a person of ordinary skill in the art.

Claims

1. An elastic collar and a stopper-matched needle-stick prevention device, characterized in that: include: The catheter seat assembly has an anti-drop structure at its rear end; A needle protection sleeve, which is provided with a needle through hole extending along the axis, the front part of which is inserted from the rear end of the catheter seat assembly, the front end of the outer wall of which is provided with a slide groove, the slide groove divides the front end of the needle through hole into two sections, and the rear end of the outer wall of which is provided with a slot, the slot divides the rear end of the needle through hole into two sections; An elastic collar is sleeved on the front end of the outer wall of the needle protection sleeve through elastic deformation and corresponds to the position of the slide groove; The stopper is slidably mounted in the slide groove of the needle shield, and one side of the stopper facing the inside of the slide groove of the needle shield cooperates with the needle tube, and the other side of the stopper facing the outside of the slide groove of the needle shield is supported on the inner wall of the elastic collar, and the rear part of the stopper cooperates with the anti-drop structure of the catheter seat assembly; A stopper is installed in the slot of the needle protection sleeve and is provided with a stopper hole corresponding to the needle through hole; A needle seat, covering the rear portion of the needle guard; The needle tube passes through the catheter seat assembly, the needle through hole of the needle protective sleeve, and the stop hole of the limit plate, and provides support for the stopper. Its rear end is fixed in the needle seat, and a protruding buckle with a size larger than the stop hole of the limit plate is provided near the front end of its outer wall; The needle seat is pulled backwards, driving the needle tube to retreat axially together. When the needle tube retreats to the point where the protruding buckle is blocked by the stop hole of the limiting plate, the front end of the needle tube retreats and leaves the block. The block loses the support of the needle tube, and under the elastic restoring force of the elastic ring, the block is separated from the anti-detachment structure of the catheter seat assembly and slides into the sliding groove of the needle shield, so that the block blocks the front end of the needle through hole of the needle shield to prevent the front end of the needle tube from extending forward. The needle shield, the block and the limiting plate shield the front end of the needle tube. The needle seat continues to be pulled backwards, driving the limit plate through the raised buckle of the needle tube, and then driving the needle shield and the elastic ring and block thereon to move backwards together. When the needle shield is pulled out from the rear end of the catheter seat assembly, it is separated from the catheter seat assembly.

2. The elastic collar and stopper cooperation type needle stick prevention device according to claim 1, characterized in that: The anti-drop structure of the catheter seat assembly is a circumferentially inwardly concave annular groove at the rear end of the inner wall of the catheter seat, and the rear side of the stopper is provided with a stop protrusion matched with the annular groove of the catheter seat.

3. The elastic collar and stopper cooperation type needle stick prevention device according to claim 1, characterized in that: The anti-drop structure of the catheter seat assembly is a slot penetrating the side wall of the catheter seat, and the rear side of the other side of the stopper is provided with a stop protrusion matched with the slot of the catheter seat.

4. The elastic collar and block cooperation type needle stick prevention device according to any one of claims 1 to 3, characterized in that: A positioning groove for the elastic ring to be inserted into is arranged on the other side of the stopper.

5. The elastic collar and stopper cooperation type needle stick prevention device according to claim 3, characterized in that: Positioning convex ribs matching with the sliding grooves of the needle protection sleeve are arranged on both sides of the stopper.

6. The elastic collar and block cooperation type needle stick prevention device according to any one of claims 1 to 3 and 5, characterized in that: The front side, the rear side and both sides of the stopper are provided with positioning surfaces matched with the sliding groove of the needle protection sleeve.

7. The elastic collar and block cooperation type needle stick prevention device according to any one of claims 1 to 3 and 5, characterized in that: An annular positioning groove which is concave in the circumferential direction is provided at the front end of the outer wall of the needle protection sleeve. A positioning plane which is parallel to the axis is provided on the bottom surface of the annular positioning groove. A sliding groove is provided on the positioning plane. Both the sliding groove and the slot are arranged along the radial surface. The elastic ring is sleeved in the annular positioning groove by elastic deformation.

8. The elastic collar and block cooperation type needle stick prevention device according to any one of claims 1 to 3 and 5, characterized in that: The limiting piece is in an L-shaped sheet shape, one side of the limiting piece is installed in the slot of the needle protective sleeve and is provided with a stop hole, and the other side of the limiting piece is arranged on the outer wall of the needle protective sleeve.

9. The elastic collar and stopper cooperation type needle stick prevention device according to claim 8, characterized in that: The edge of the stop hole of the limit plate is provided with a flange.

10. The elastic collar and stopper cooperation type needle stick prevention device according to claim 1, characterized in that: A groove connected to the inner hole is provided at the front end of the needle tube, and a side of the block that cooperates with the needle tube adopts an arc transition with the front side surface. When the needle tube retreats and passes through the block, one side of the block is tightly attached to the outer wall of the needle tube under the elastic restoring force of the elastic ring and is located outside the groove of the needle tube, so that the needle tube retreats smoothly.

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