A needle-puncture prevention device with elastic collar and baffle

Abstract

An elastic collar and a baffle 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 baffle, which is slidably installed in the slide groove, a part of which 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 covers the rear part of the needle shield; a needle tube, which passes through the catheter seat assembly, the needle shield, the baffle, and the limit plate, and provides support for the baffle, and the rear end 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 backward. 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 baffle, and the baffle 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 baffle 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 comprises an elastic collar and a baffle.

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

[0005] An elastic collar and a baffle-coordinated 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 baffle is slidably mounted in the slide groove of the needle protection sleeve, and is provided with a slot hole matched with the needle tube, a part of which is arranged outside the slide groove, supported on the inner wall of the elastic ring, and matched 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, the slot hole of the baffle, and the stop hole of the limit plate, and provides support for the baffle. 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 baffle, and the baffle loses the support of the needle tube. Under the elastic restoring force of the elastic ring, the baffle 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 baffle 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, baffle and 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 baffle 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 baffle may adopt the following two solutions.

[0015] One solution is that the baffle includes a stopper, a bending connection part, and a supporting part connected in sequence, the stopper can be slidably installed in the slide groove of the needle shield, the stopper is provided with a slot hole that matches the needle tube, the bending connection part and the supporting part are arranged outside the slide groove, the supporting part is supported on the inner wall of the elastic ring, and matches with the anti-detachment structure of the catheter seat assembly. Furthermore, when the needle tube provides support for the baffle, the elastic ring is combined with the anti-detachment structure of the catheter seat assembly under the support of the baffle support part; when the baffle loses the support of the needle tube, the elastic ring is separated from the anti-detachment structure under the action of the elastic restoring force, so that the needle shield and the catheter seat assembly can be separated.

[0016] Another solution is that the baffle includes a stopper, a support part, and a stopper connected in sequence, the stopper can be slidably installed in the slide groove of the needle shield, the stopper is provided with a slot matched with the needle tube, the support part and the stopper are arranged outside the slide groove, the support part is supported on the inner wall of the elastic collar, the stopper is connected to the rear side of the support part, and matches with the anti-slip structure of the catheter seat assembly. Furthermore, when the needle tube provides support for the baffle, the stopper of the baffle is combined with the anti-slip structure of the catheter seat assembly; when the baffle that loses the support of the needle tube slides into the slide groove of the needle shield under the elastic restoring force of the elastic collar, the stopper of the baffle is separated from the anti-slip structure, so that the needle shield and the catheter seat assembly can be separated.

[0017] To further refine the above technical solution, 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 parallel to the axis is provided on the bottom surface of the annular positioning groove, a sliding groove is provided on the positioning plane, the sliding groove and the slot are both arranged along the radial surface, and the elastic ring is elastically deformed and sleeved in the annular positioning groove.

[0018] A groove is provided at the front end of the outer wall of the needle protection sleeve, and the groove is communicated with the needle through hole and the rear side groove wall of the annular positioning groove.

[0019] A concave table surface which is parallel to the axis and concave inward is provided at the rear end of the outer wall of the needle protection sleeve, and the concave table surface is arranged corresponding to the notch of the slot.

[0020] The anti-drop structure of the catheter seat assembly is a circular groove which is circumferentially concave at the rear end of the inner wall of the catheter seat.

[0021] The axial distance between the front end of the needle tube and the protruding buckle is smaller than the axial distance between the blocking piece and the limiting piece.

[0022] 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 blocking plate. The blocking plate loses the support of the needle tube and slides into the sliding groove of the needle protective sleeve under the elastic restoring force of the elastic ring, thereby blocking the front end of the needle through hole of the needle protective sleeve and preventing the front end of the needle tube from extending forward, thereby shielding the front end needle tip of the needle tube in the needle protective sleeve and improving the safety of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the decomposition structure of Example 1.

[0024] Figure 2 This is a full cross-sectional view of Example 1.

[0025] Figure 3 Schematic diagram of the structure of the catheter seat assembly in Example 1.

[0026] Figure 4 It is a partial cross-sectional view of the catheter seat in Example 1.

[0027] Figure 5 This is a schematic diagram of the structure of the needle protection sleeve and the limiting plate in Example 1.

[0028] Figure 6 This is a partial cross-sectional view of Example 1.

[0029] Figure 7 It is a schematic diagram of the cross-sectional shape of the elastic collar sleeved on the groove bottom surface and the positioning plane of the annular positioning groove of the needle shield when the blocking piece in Example 1 is not installed in the needle shield.

[0030] Figure 8 Schematic diagram of the structure of the baffle in Example 1.

[0031] Fig. 9 This is a schematic diagram of the structure of the needle seat and needle tube in Example 1.

[0032] Fig.10 It is a partial cross-sectional view of Example 1 entering the self-destruct state.

[0033] 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.

[0034] Figures 1 to 11 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 ring;

[0038] 4 blocking piece, 401 stopping portion, 4011 positioning edge, 4012 notch, 402 bending connection portion, 403 supporting portion;

[0039] 5 limit pieces, 501 stop holes;

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

[0041] 7 needle tube, 701 raised buckle.

[0042] Fig.12 Schematic diagram of the structure of the baffle in Example 2.

[0043] Fig.13 This is a partial cross-sectional view of Example 2.

[0044] Fig.14 It is a partial cross-sectional view of Example 2 entering the self-destruct state.

[0045] Fig.15 This is a schematic diagram of the structure of Example 2 after entering the self-destruct state and separating from the catheter seat assembly.

[0046] Figures 12 to 15 The baffles in the following are marked as follows, and the other parts are marked as follows Figures 1 to 11 :

[0047] 4 blocking piece, 401 stopping portion, 4011 positioning edge, 4012 notch, 402 supporting portion, 403 stopping portion.

[0048] Fig.16 Another structural schematic diagram of the baffle.

[0049] Fig.17 It is another structural schematic diagram of the baffle. DETAILED DESCRIPTION

[0050] 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.

[0051] Example 1

[0052] See also Figure 1 and Figure 2 A needle-stick prevention device with an elastic collar and a baffle comprises a catheter seat assembly 1, a needle protection sleeve 2, an elastic collar 3, a baffle 4, a limiting plate 5, a needle seat 6, and a needle tube 7.

[0053] 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. The anti-slip structure of this embodiment is used to increase the anti-slip force between the inner wall of the catheter seat 101 and the elastic ring 3 to prevent the elastic ring 3 from falling off. Figure 4 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 .

[0054] 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 5 The needle protection sleeve 2 is cylindrical, and a needle through hole 201 is provided inside the needle protection sleeve 2 along the axis. An annular positioning groove 202 is provided at the front end of the outer wall of the needle protection sleeve 2, which is concave in the circumferential direction. The bottom surface of the annular positioning groove 202 is provided with a positioning plane 203 parallel to the axis of the needle protection sleeve 2. 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 annular positioning groove 202. The annular positioning groove 202 and the positioning plane 203 are both used to install the elastic collar 3. The groove walls on the front and rear sides of the annular positioning groove 202 block the elastic collar 3 to prevent its axial movement. The positioning plane 203 is provided with a slide groove 204 arranged along the radial surface of the needle protection sleeve 2. The slide groove 204 divides the front end of the needle through hole 201 into two sections. The slide groove 204 is used to install the blocking piece 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 .

[0055] See also Figure 2 and Figure 6The elastic collar 3 is elastically deformed and sleeved in the annular positioning groove 202 of the needle protection sleeve 2. The inner diameter of the elastic collar 3 is smaller than the bottom diameter of the annular positioning groove 202. When the baffle 4 is not installed in the needle protection sleeve 2, the inner wall of the elastic collar 3 is tightly attached to the bottom surface of the annular positioning groove 202 and the positioning plane 203. At this time, the cross-sectional shape of the elastic collar 3 is shown in FIG. Figure 7 .

[0056] The baffle 4 is installed in the slide groove 204 of the needle protection sleeve 2 and can slide along the vertical direction of the positioning plane 203. A part of the baffle 4 is arranged outside the slide groove 204 and supported on the inner wall of the elastic ring 3 along the vertical direction of the positioning plane 203. The baffle 4 is provided with a slot hole matched with the needle tube 7. The baffle 4 can adopt various structural forms.

[0057] The structure of the baffle 4 in this embodiment is shown in FIG. Figure 8 The baffle 4 is in the shape of a bent sheet, and includes a stopper 401, a bent connection portion 402, and a support portion 403 that are sequentially connected. Figure 6 The stopper 401 is installed in the slide groove 204 of the needle shield 2 and can slide along the vertical direction of the positioning plane 203. The two sides of the stopper 401 are provided with positioning edges 4011 that match the slide groove 204. The edge of the stopper 401 is provided with a notch 4012 facing the slide groove 204. The notch 4012 is a structural form of the above-mentioned slot. The bending connection part 402 and the supporting part 403 are arranged outside the slide groove 204. The bending connection part 402 is V-shaped or U-shaped and the inner side is arranged forward. Figure 5 and Figure 6 The front end of the outer wall of the needle shield 2 shown is also provided with a groove 206 corresponding to the bent connection portion 402, the groove 206 extends in the vertical direction of the positioning plane 203 and is connected to the needle through hole 201 and the rear side groove wall of the annular positioning groove 202, and the support portion 403 is supported on the inner wall of the elastic ring 3.

[0058] See also Figure 2 and Figure 5 The stopper 5 is interference-fitted in the slot 205 of the needle shield 2, and a stopper hole 501 corresponding to the needle through hole 201 of the needle shield 2 is provided on the stopper 5. A concave table 207 parallel to the axis of the needle shield 2 and concave inward is also provided at the rear end of the outer wall of the needle shield 2, and the concave table 207 is arranged corresponding to the notch of the slot 205, so as to facilitate the assembly and disassembly of the stopper 5.

[0059] See also Figure 2 and Fig. 9The 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, the notch 4012 of the baffle 4, and the stop hole 501 of the limiting plate 5. 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, the needle through hole 201 of the needle protective sleeve 2, and the notch 4012 of the baffle 4. 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 stop portion 401 of the baffle 4 and the limiting plate 5.

[0060] During assembly, first install the stopper 401, the bent connection part 402, and the support part 403 of the baffle 4 into the slide groove 204, the groove 206, and the annular positioning groove 202 of the needle shield 2, respectively, and install 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 notch 4012 of the baffle 4 and the stop hole 501 of the limit plate 5 in sequence, 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 through the inner hole of the needle seat 6 and fixed with environmentally friendly quick-drying glue. Then, the rear part of the needle shield 2 is inserted 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. At the same time or successively, the elastic collar 3 is sleeved into the annular positioning groove 202 of the needle shield 2, so that the supporting part 403 of the blocking piece 4 is supported on the inner wall of the elastic collar 3. 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 elastic ring 3 is inserted into the annular groove 1011 at the rear end of the inner wall of the catheter seat 101, and friction is generated by interference contact. The needle shield 2 maintains a good connection with the catheter seat 101 without external force through this friction. The assembly of the anti-needlestick device is completed, and the anti-needlestick device is in an unused state.

[0061] 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 stop hole 501 of the stop plate 5, the front end of the needle tube 7 exits the notch 4012 of the stop plate 4, and the stop plate 4 loses the support of the needle tube 7. Under the elastic restoring force of the elastic collar 3, the stop plate 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 and preventing 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 plate 4 and the stop 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-needle puncture device enters a self-destructive state. At the same time, the elastic collar 3 escapes from the annular groove 1011 at the rear end of the inner wall of the catheter seat 101 and leaves the inner wall of the catheter seat 101, and the friction between the elastic collar 3 and the inner wall of the catheter seat 101 fails.

[0062] 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 baffle 4 thereon to move backward together, and the needle shield 2 is pulled out from the rear end of the catheter seat 101 to achieve separation from the catheter seat assembly 1.

[0063] Example 2

[0064] The main difference from the first embodiment lies in the structure of the baffle 4 .

[0065] See also Fig.12 The baffle 4 is in the shape of a bent sheet, and includes a stopper 401, a support portion 402, and a stopper 403 connected in sequence. Fig.13 The stopper 401 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. Positioning edges 4011 that match the slide groove 204 are provided on both sides of the stopper 401. The edge of the stopper 401 is provided with a notch 4012 that matches the needle tube 7 and faces the slide groove 204. The support part 402 and the stopper 403 are arranged outside the slide groove 204. The support part 402 is bent backward relative to the stopper 401 and is supported on the inner wall of the elastic ring 3. The stopper 403 is connected to the rear side of the support part 402.

[0066] The anti-drop structure at the rear end of the inner wall of the catheter seat 101 is still a circumferentially concave annular groove 1011 , but in this embodiment, it cooperates with the stop portion 403 of the baffle 4 instead of the elastic ring 3 .

[0067] See also Fig.13 The difference during assembly is that when the front part of the needle shield 2 is installed into the catheter seat 101 from the rear end of the catheter seat 101, the stopper 403 of the baffle 4 is inserted into the annular groove 1011 at the rear end of the inner wall of the catheter seat 101 to achieve axial limitation, so that the needle shield 2 maintains a good connection with the catheter seat 101 without external force. Please refer to Example 1 for assembly instructions of other components.

[0068] See also Fig.14 , the difference when the needle stick prevention device enters the self-destruction state is that when the baffle 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 stopper 403 of the baffle 4 escapes from the annular groove 1011 at the rear end of the inner wall of the catheter seat 101, and the anti-slip function between the baffle 4 and the inner wall of the catheter seat 101 fails, and then the baffle 4 can be separated from the catheter seat assembly 1 as a whole. The final state is shown in FIG. Fig.15 .

[0069] In addition to the above two embodiments, the baffle 4 can also be Fig.16 and Fig.17 The flat sheet structure is shown, and the baffle 4 can be Fig.16 The shape shown in FIG. 1 has a notch thereon and can also be Fig.17 The shape shown has a through hole thereon, and slots of other shapes and other structural forms may also be used, as long as the baffle 4 can block the front end of the needle through hole 201 of the needle shield 2 after the support of the needle tube 7 is lost, thereby preventing the front end of the needle tube 7 from extending forward.

[0070] 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 baffle-type needle-stick protection 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 baffle is slidably mounted in the slide groove of the needle protection sleeve, and is provided with a slot hole matched with the needle tube, a part of which is arranged outside the slide groove, supported on the inner wall of the elastic ring, and matched 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, the slot hole of the baffle, and the stop hole of the limit plate, and provides support for the baffle. 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 blocking plate. The blocking plate loses the support of the needle tube, and under the elastic restoring force of the elastic ring, the blocking plate is separated from the anti-detachment structure of the catheter seat assembly and slides into the sliding groove of the needle guard sleeve, so that the blocking plate 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 blocking plate and the limiting plate shield the front end of the needle tube. 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 shield and the elastic ring and baffle thereon to move backward 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 baffle cooperation type needle stick prevention device according to claim 1, characterized in that: The blocking piece includes a stopper, a bent connecting portion, and a supporting portion which are connected in sequence. The stopper can be slidably installed in the slide groove of the needle protection sleeve. The stopper is provided with a slot hole which matches the needle tube. The bent connecting portion and the supporting portion are arranged outside the slide groove. The supporting portion is supported on the inner wall of the elastic ring and matches with the anti-detachment structure of the catheter seat assembly.

3. The elastic collar and baffle cooperation type needle stick prevention device according to claim 2, characterized in that: When the needle tube provides support for the baffle, the elastic ring is combined with the anti-detachment structure of the catheter seat assembly under the support of the baffle support part; when the baffle loses the support of the needle tube, the elastic ring is separated from the anti-detachment structure under the action of the elastic restoring force, so that the needle guard sleeve and the catheter seat assembly can be separated.

4. The elastic collar and baffle cooperation type needle stick prevention device according to claim 1, characterized in that: The blocking piece includes a stopper, a supporting part, and a stopper which are connected in sequence. The stopper can be slidably installed in the slide groove of the needle protection sleeve. The stopper is provided with a slot hole which matches with the needle tube. The supporting part and the stopper are arranged outside the slide groove. The supporting part is supported on the inner wall of the elastic ring. The stopper is connected to the rear side of the supporting part and matches with the anti-detachment structure of the catheter seat assembly.

5. The elastic collar and baffle cooperation type needle stick prevention device according to claim 4, characterized in that: When the needle tube provides support for the baffle, the stop portion of the baffle is combined with the anti-detachment structure of the catheter seat assembly; when the baffle that loses the support of the needle tube slides into the slide groove of the needle guard sleeve under the elastic restoring force of the elastic ring, the stop portion of the baffle is separated from the anti-detachment structure, so that the needle guard sleeve and the catheter seat assembly can be separated.

6. The elastic collar and baffle cooperation type needle stick prevention device according to any one of claims 1 to 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.

7. The elastic collar and baffle cooperation type needle stick prevention device according to claim 6, characterized in that: A groove is provided at the front end of the outer wall of the needle protection sleeve, and the groove is communicated with the needle through hole and the rear side groove wall of the annular positioning groove.

8. The elastic collar and baffle cooperation type needle stick prevention device according to any one of claims 1 to 5 and 7, characterized in that: A concave table surface which is parallel to the axis and concave inward is provided at the rear end of the outer wall of the needle protection sleeve, and the concave table surface is arranged corresponding to the notch of the slot.

9. The elastic collar and baffle cooperation type needle stick prevention device according to any one of claims 1 to 5 and 7, characterized in that: The anti-drop structure of the catheter seat assembly is a circular groove which is circumferentially concave at the rear end of the inner wall of the catheter seat.

10. The elastic collar and baffle cooperation type needle stick prevention device according to any one of claims 1 to 5 and 7, characterized in that: The axial distance between the front end of the needle tube and the protruding buckle is smaller than the axial distance between the blocking piece and the limiting piece.

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