A medical safety rebound syringe

Abstract

The invention discloses a medical safety rebound type syringe, and particularly relates to the technical field of medical instruments. The invention provides an elastic sheet, and initially, a needle seat is installed in a mounting seat, and then the elastic sheet is pressed downward to fix the needle seat, and under the push of a core rod, the hexagonal plastic spring sheet triggers the needle seat to rebound, and due to the elasticity of the elastic sheet, a smaller trigger force can trigger the rebound, and the rebound is more accurate; during the rebound action, the pressing thrust is borne by the plastic hexagonal elastic piece, and the hexagonal plastic elastic piece squeezes and pushes the needle seat forward to push the compression spring on the one hand, and squeezes the spring sheet backward on the other hand, so that the spring sheet is deformed, and the hexagonal plastic elastic piece leaves the rebound seat and then rebounds into the inner cavity of the core rod, and under the rebound force of the compression spring, the hexagonal plastic elastic piece and the needle seat are successively rebounded into the inner cavity of the core rod and leave the inclined end of the limiting spring plate, so that the injection needle is covered in the inner cavity of the core rod, so as to better protect the injection needle from being exposed after use, and avoid cross infection.

Description

Technical Field

[0001] The invention relates to the technical field of medical instruments, in particular to a medical safety rebound syringe. Background Art

[0002] A medical syringe is a medical device consisting of a needle, a syringe and a piston. It is widely used in the medical field for injecting drugs, drawing blood or vaccines, etc. With the development of medicine, syringes have gradually become an indispensable part of medical equipment. Modern syringes are mostly made of plastic and are thrown away after one use, which greatly reduces the risk of infection during injection.

[0003] After searching, the invention patent with publication number CN108578832B discloses a pressure-rebound speed-limiting syringe, which has good speed-maintaining and buffering effects; it is suitable for the injection of various drugs and is also suitable for the selection of different injection positions.

[0004] In the above scheme, the needle of the syringe cannot be automatically triggered to rebound and retracted after use, and is prone to secondary infection when discarded. The prior art also adopts a method of sliding the syringe body in the outer cylinder to extend or retract the needle on the syringe body. During injection, this method requires pressing down the inner cylinder and fixing the inner cylinder with the limit assembly. The limit needs to be released during rebound, which is complicated to operate and has high requirements for the operator. It also requires the cooperation of two hands, and it is also impossible to trigger rebound, and has poor portability. Summary of the invention

[0005] The object of the present invention is to provide a medical safety rebound syringe to solve the problems mentioned in the above background technology.

[0006] The present invention can be implemented through the following technical scheme: a medical safety rebound syringe, comprising a syringe barrel, characterized in that: a core rod with a cavity is movably provided in the inner cavity of the syringe barrel, and a semi-enclosed mounting shell is provided at the end of the syringe barrel, a needle seat is elastically clamped inside the mounting shell, two elastic sheets are symmetrically provided on the surface of the mounting shell, an inner wall surface of each of the elastic sheets is provided with an inner buckle, an injection needle is fixedly connected to the middle of one side of the needle seat, and a fitting surface is provided on the other side surface of the needle seat, a ring plate movably passing through the inside of the mounting shell is fixedly connected to the outer surface of the end of the other side of the needle seat, two outer buckles clamped into the corresponding inner buckles are fixedly connected to one side of the ring plate, and a compression spring is fixedly connected to one side of the ring plate;

[0007] A rebound seat is provided on one side of the core rod, and a connecting ring with an annular structure is provided on the outside of one side of the rebound seat. A rubber plug is clamped on the outside of the rebound seat and slides along the inner cavity of the syringe barrel and abuts against the inner cavity end surface of the syringe barrel. A hexagonal plastic elastic part that passes through the inside of the rubber plug slides and abuts against the inside of the rebound seat, and a contact surface that cooperates with the fitting surface is provided on one side surface of the hexagonal plastic elastic part.

[0008] A further technical improvement of the present invention is that: the inner cavity of the rubber plug is provided with an annular cavity which is engaged with the connecting ring, the inner wall surface of the rebound seat is equally divided into six limiting slide grooves, and the end of each limiting slide groove is provided with an inclined portion;

[0009] The outer wall surface of the hexagonal plastic elastic part is provided with six convex strips that slide in cooperation with the corresponding limiting sliding grooves, and the end surface of the convex strips is in contact with the inner wall surface of the annular cavity. The side of the hexagonal plastic elastic part away from the contact surface is provided with an annular recess, and the surface of the annular recess is evenly divided with six spring pieces that are in contact with the corresponding inclined parts.

[0010] A further technical improvement of the present invention is that: the inner wall surface of the mounting shell is provided with a snap ring seat for the end of the compression spring to enter, and the end of the compression spring is not fixedly connected to the snap ring seat.

[0011] A further technical improvement of the present invention is that two limiting spring plates inclined inwardly and used for limiting and blocking the needle seat are symmetrically arranged on the inner wall surface of the core rod.

[0012] A further technical improvement of the present invention is that: an assembly ring is sleeved on the end of the needle seat, a needle shield for protection is sleeved on the outside of the injection needle, and the needle shield is in a cooperative connection with the mounting shell.

[0013] A further technical improvement of the present invention is that the method for using the syringe comprises the following steps:

[0014] Step 1: Install the needle seat into the mounting shell connected to the syringe barrel, and use the elastic sheet to clamp and fix the needle seat;

[0015] Step 2: After the needle is installed in place, press the elastic sheet downward to make the inner buckle engage with the outer buckle, thereby fixing the needle seat, and injecting the liquid using the injection needle in the needle seat;

[0016] Step 3: After the injection is completed, the core rod pushes the hexagonal plastic elastic part and the rubber plug to move together to the end position of the inner cavity of the syringe barrel, and the contact surface of the end face of the hexagonal plastic elastic part fits the extrusion fitting surface, and at the same time, a reverse thrust is generated on the hexagonal plastic elastic part and enters the inner cavity of the core rod. At this time, the needle seat is pushed to one side and then squeezes the elastic sheet upward, so that the needle seat rebounds;

[0017] Step 4: During the rebound process, since the buckle restriction on the needle seat is released, the compression spring generates a rebound thrust from the tensioned state, pushing the needle seat through the interior of the rebound seat into the inner cavity of the core rod, and the needle seat drives the injection needle into the inner cavity of the core rod until the needle seat passes through the inclined ends of the two limiting spring plates.

[0018] A further technical improvement of the present invention is that in step three, under the push of the core rod, the rebound seat drives the rubber plug outside it to fit with the inner cavity end of the syringe barrel. At this time, the contact surface on the hexagonal plastic elastic part contacts the fitting surface and exerts a thrust on the needle seat, which is pushed to one side by the outer buckle and leaves the inside of the inner buckle, so that the elastic sheet breaks away from the contact with the needle seat upward and rebounds the needle seat.

[0019] A further technical improvement of the present invention is that in step three, while the hexagonal plastic elastic part pushes the needle seat, it also generates a reverse thrust on the hexagonal plastic elastic part. After receiving the thrust, the spring sheet on the hexagonal plastic elastic part is deformed and ejected from the inclined portion, completing the triggering action.

[0020] A further technical improvement of the present invention is that in step four, the hexagonal plastic elastic part first passes through the interior of the rebound seat and squeezes the inclined ends of the two limiting spring plates out of the inner cavity of the core rod, and then the needle seat passes through the rebound seat under the rebound thrust of the compression spring until it leaves the inclined ends of the limiting spring plates, and the injection needle rebounds and remains in the inner cavity of the core rod.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention uses an elastic sheet to initially install the needle seat into the mounting seat, and then press the elastic sheet downward to fix the needle seat. Under the push of the core rod, the hexagonal plastic spring triggers the needle seat to rebound. Due to the elasticity of the elastic sheet, a smaller trigger force can trigger the rebound, and the rebound is more accurate, which improves portability;

[0023] 2. During the rebound action, the hexagonal plastic elastic part bears the pressing thrust. On the one hand, the hexagonal plastic elastic part squeezes the needle seat to push the compression spring forward, and on the other hand, it squeezes the spring sheet backward, so that the spring sheet is deformed and slides from the inclined portion. At this time, the hexagonal plastic elastic part leaves the rebound seat and rebounds into the inner cavity of the core rod. At this time, the hexagonal plastic elastic part is separated from the rebound seat, and the compression spring generates a rebound thrust from the tensioned state. Under the rebound thrust, the needle seat drives the injection needle to pass through the inside of the rebound seat and is covered in the inner cavity of the core rod, so as to better protect the injection needle from being exposed after use, avoid cross infection caused by the injection needle due to loss of the needle cover, prevent secondary use, and reduce the risk of secondary infection;

[0024] 3. The hexagonal plastic spring and the needle seat are successively ejected into the inner cavity of the core rod and leave the inclined end of the limiting spring plate. The inclined end of the limiting spring plate is used to limit the needle seat to prevent the injection needle from leaving the inner cavity of the core rod;

[0025] 4. The outer snap buckle and the inner snap buckle are used to realize the restricted installation of the needle seat, which can withstand a larger injection force during injection. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0027] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0028] Figure 2 This is a schematic diagram of the three-dimensional structure of the needle cover after installation of the present invention;

[0029] Figure 3 It is a schematic diagram of the three-dimensional disassembled structure of the interior of the syringe barrel of the present invention;

[0030] Figure 4 for Figure 3 A schematic diagram of the three-dimensional structure from another angle;

[0031] Figure 5 It is a three-dimensional cross-sectional view of the present invention in a non-rebound state;

[0032] Figure 6 For the present invention Figure 5 A partial enlarged view of the middle A;

[0033] Figure 7 It is a three-dimensional exploded cross-sectional view of the syringe barrel of the present invention;

[0034] Figure 8 For the present invention Figure 7 A partial enlarged view of point B in the middle;

[0035] Fig. 9 It is a three-dimensional cross-sectional view of the present invention in a rebound state;

[0036] Fig.10 It is a flowchart of the process steps when the present invention is used.

[0037] In the figure: 1. syringe barrel; 2. core rod; 3. needle cover; 4. injection needle; 5. needle seat; 6. hexagonal plastic elastic part; 7. rubber plug; 8. limiting spring plate; 9. elastic sheet; 10. ring plate; 12. outer snap buckle; 13. compression spring; 14. rebound seat; 15. connecting ring; 16. ring cavity; 17. convex strip; 18. spring sheet; 19. limiting slide groove; 20. inner snap buckle; 21. snap ring seat; 22. assembly ring; 23. mounting shell; 24. inclined portion; 25. ring recess; 26. contact surface; 27. fitting surface. DETAILED DESCRIPTION

[0038] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0039] See also Figure 1-Figure 10 As shown, the present invention provides a medical safety rebound syringe, comprising a syringe barrel 1, the inner cavity of the syringe barrel 1 is movably provided with a core rod 2 with a cavity, and the end of the syringe barrel 1 is provided with a semi-enclosed mounting shell 23, the interior of the mounting shell 23 is elastically clamped with a needle seat 5, and the surface of the mounting shell 23 is symmetrically provided with two elastic sheets 9, initially, the elastic sheets 9 do not contact the needle seat 5, the inner wall surface of each elastic sheet 9 is provided with an inner buckle 20, an injection needle 4 is fixedly connected to the middle part of one side of the needle seat 5, and the other side surface of the needle seat 5 is provided with a fitting surface 27, and the outer surface of the other side end of the needle seat 5 is fixedly connected with a movable through The ring plate 10 inside the mounting shell 23, one side of the ring plate 10 is fixedly connected with two outer buckles 12 that are snapped into the corresponding inner buckles 20, and one side of the ring plate 10 is fixedly connected with a compression spring 13, the injection needle 4 includes a needle tip, a needle stem and a needle plug, and the needle plug part is fixedly connected to the middle part of the needle seat 5, wherein the connection between the needle seat 5 and the injection needle 4 is the prior art, when the injection needle 4 is installed into the mounting shell 23 following the needle seat 5, the outer buckle 12 is aligned with the position of the inner buckle 20, and then the elastic sheet 9 is pressed downward, at which time the inner buckle 20 is snapped with the outer buckle 12, the needle seat 5 is fixed, and the stable use of the injection needle 4 is convenient;

[0040] A rebound seat 14 is provided on one side of the core rod 2, and a connecting ring 15 of an annular structure is provided on the outside of one side of the rebound seat 14. A rubber plug 7 that slides along the inner cavity of the syringe barrel 1 and abuts against the inner cavity end surface of the syringe barrel 1 is clamped on the outside of the rebound seat 14. A hexagonal plastic elastic part 6 that passes through the inside of the rubber plug 7 is slidably abutted inside the rebound seat 14. A contact surface 26 that cooperates with the fitting surface 27 is provided on one side surface of the hexagonal plastic elastic part 6. In the use scenario, the hexagonal plastic elastic part 6 moves together with the rebound seat 14, and the rubber plug 7 is used to slide along the inner cavity of the syringe barrel 1. 7 contacts with the inner wall surface of the syringe barrel 1, and at this time, the contact surface 26 on the hexagonal plastic elastic part 6 contacts with the fitting surface 27 on the needle seat 5, generating a thrust on one side of the needle seat 5, so that the needle seat 5 is pushed toward the end of the semi-closed mounting shell 23. Under the external pushing force, the outer buckle 12 is disengaged from the inner buckle 20, and the elastic sheet 9 rises, releasing the restriction on the needle seat 5; at the same time, the hexagonal plastic elastic part 6 bears the pressing thrust, and the hexagonal plastic elastic part 6 is squeezed and deformed in the rebound seat 14 and leaves the rebound seat 14 and then rebounds into the inner cavity of the core rod 2.

[0041] The rubber plug 7 squeezes and pushes the liquid under the external force of the core rod 2, and the liquid in the syringe barrel 1 is injected into the human body through the needle tip of the injection needle 4, thereby achieving infusion into the human body.

[0042] See also Figure 4 , Figure 7 and Figure 8 As shown, the inner cavity of the rubber plug 7 is provided with an annular cavity 16 which is engaged with the connecting ring 15, and the inner wall surface of the rebound seat 14 is equally divided into six limiting slide grooves 19, and the end of each limiting slide groove 19 is provided with an inclined portion 24;

[0043] Six convex strips 17 are provided on the outer wall surface of the hexagonal plastic elastic part 6 to slide with the corresponding limiting slide grooves 19, and the end surface of the convex strip 17 is in contact with the inner wall surface of the annular cavity 16. A ring recess 25 is provided on the side of the hexagonal plastic elastic part 6 away from the contact surface 26, and six spring pieces 18 are equally divided on the surface of the ring recess 25 to be in contact with the corresponding inclined parts 24.

[0044] The six convex strips 17 and the spring 18 on the hexagonal plastic elastic part 6 all slide in the corresponding limiting slide grooves 19, and the hexagonal plastic elastic part 6 is restricted by the cooperation of the inclined portion 24 and the spring 18. When the rubber plug 7 moves to the inner cavity end of the syringe barrel 1, the hexagonal plastic elastic part 6 squeezes and pushes the needle seat 5 forward on the one hand, and squeezes the spring 18 backward on the other hand, so that the spring 18 is deformed and slides away from the inclined portion 24. At this time, the hexagonal plastic elastic part 6 is separated from the rebound seat 14, and the rebound operation is carried out.

[0045] See also Figure 5 and Figure 6 As shown, the inner wall surface of the mounting shell 23 is provided with a snap ring seat 21 for the end of the compression spring 13 to enter, and the end of the compression spring 13 is not fixedly connected to the snap ring seat 21. When the compression spring 13 rebounds, one end of the compression spring 13 detaches from the interior of the snap ring seat 21.

[0046] See also Figure 7 and Fig. 9 As shown, the inner wall surface of the core rod 2 is symmetrically provided with two limiting spring plates 8 which are inclined inwards and are used to limit and block the needle seat 5. Under the rebound force of the compression spring 13, the hexagonal plastic elastic part 6 and the needle seat 5 pass through the inclined ends of the limiting spring plates 8 in sequence, and the needle seat 5 drives the injection needle 4 to rebound. At this time, the injection needle 4 is covered in the inner cavity of the core rod 2, so as to better protect the injection needle 4 from being exposed after use.

[0047] See also Figure 2 and Figure 6 As shown, the end of the needle seat 5 is sleeved with a mounting ring 22 , the outer portion of the injection needle 4 is sleeved with a needle shield 3 for protection, and the needle shield 3 is in cooperation connection with the mounting shell 23 .

[0048] See also Fig.10 ,Depend on Fig.10Ad in the figure respectively represent the basic steps of the present application when in use; a is the state in which the needle seat 5 is installed in the syringe barrel 1, and then the elastic sheet 9 is pressed downward so that the inner snap 20 is engaged with the outer snap 12, as shown in b; then the core rod 2 is pressed and pushed, and a thrust to one side is applied to the core rod 2 until the rubber plug 7 fits with the inner wall of the syringe barrel 1, as shown in c; at this time, the elastic sheet 9 and the hexagonal plastic elastic part 6 are triggered, and under the rebound of the compression spring 13, the hexagonal plastic elastic part 6 and the needle seat 5 are successively ejected into the inner cavity of the core rod 2 and leave the inclined end of the limiting spring plate 8, as shown in d.

[0049] The use method and working principle of the medical safety rebound syringe of the present invention are as follows: first, the needle seat 5 is installed in the mounting shell 23 connected to the syringe barrel 1, and the needle seat 5 is clamped and fixed by the elastic sheet 9; after being installed in place, the elastic sheet 9 is pressed downward to make the inner buckle 20 clamped with the outer buckle 12, thereby fixing the needle seat 5, and the injection needle 4 in the needle seat 5 is used to inject liquid;

[0050] After the injection is completed, the core rod 2 pushes the hexagonal plastic elastic member 6 and the rubber plug 7 to move together to the end position of the inner cavity of the syringe barrel 1, and the contact surface 26 on the hexagonal plastic elastic member 6 contacts the fitting surface 27 on the needle seat 5, generating a thrust on one side of the needle seat 5, so that the needle seat 5 is pushed toward the end of the semi-enclosed mounting shell 23. Under the external force, the outer buckle 12 is separated from the inner buckle 20, and the elastic sheet 9 is lifted. The elastic force of the elastic sheet 9 maintains this shape, and the restriction on the needle seat 5 is released;

[0051] The hexagonal plastic elastic member 6 bears the pressing thrust, and the hexagonal plastic elastic member 6 is squeezed and deformed in the rebound seat 14 and bounces into the inner cavity of the core rod 2 after leaving the rebound seat 14. The hexagonal plastic elastic member 6 squeezes and pushes the needle seat 5 forward on the one hand, and squeezes the spring sheet 18 backward on the other hand, so that the spring sheet 18 is deformed and slides away from the inclined portion 24. At this time, the hexagonal plastic elastic member 6 is separated from the rebound seat 14 to complete the triggering action; since the buckle restriction on the needle seat 5 is released, the compression spring 13 generates a rebound thrust from the tensioned state, pushing the needle seat 5 through the inside of the rebound seat 14 into the inner cavity of the core rod 2, and the needle seat 5 drives the injection needle 4 to enter the inner cavity of the core rod 2 until the needle seat 5 passes through the inclined ends of the two limiting spring plates 8, and the injection needle 4 is covered in the inner cavity of the core rod 2, so as to better protect the injection needle 4 from being exposed after use.

[0052] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A medical safety rebound syringe, comprising a syringe barrel (1), characterized in that: The inner cavity of the syringe barrel (1) is movably provided with a core rod (2) with a cavity, and the end of the syringe barrel (1) is provided with a semi-enclosed mounting shell (23), the interior of the mounting shell (23) is elastically clamped with a needle seat (5), the surface of the mounting shell (23) is symmetrically provided with two elastic sheets (9), the inner wall surface of each elastic sheet (9) is provided with an inner buckle (20), the middle part of one side of the needle seat (5) is fixedly connected with an injection needle (4), and the other side surface of the needle seat (5) is provided with a fitting surface (27), the outer surface of the other side end of the needle seat (5) is fixedly connected with a ring plate (10) that movably passes through the interior of the mounting shell (23), one side of the ring plate (10) is fixedly connected with two outer buckles (12) that are clamped into the corresponding inner buckles (20), and one side of the ring plate (10) is fixedly connected with a compression spring (13); A rebound seat (14) is provided on one side of the core rod (2); a connecting ring (15) of an annular structure is provided on the outside of one side of the rebound seat (14); a rubber plug (7) sliding along the inner cavity of the syringe barrel (1) is clamped on the outside of the rebound seat (14); a hexagonal plastic elastic part (6) penetrating through the inside of the rubber plug (7) is slidably abutted on the inside of the rebound seat (14); a contact surface (26) for use with a fitting surface (27) is provided on one side of the surface of the hexagonal plastic elastic part (6); The inner cavity of the rubber plug (7) is provided with an annular cavity (16) which is snap-fitted with the connecting ring (15); the inner wall surface of the rebound seat (14) is equally divided into six limiting slide grooves (19); and the end of each limiting slide groove (19) is provided with an inclined portion (24); The outer wall surface of the hexagonal plastic elastic part (6) is provided with six convex strips (17) that are slidably matched with the corresponding limiting sliding grooves (19), and the end surface of the convex strip (17) is in contact with the inner wall surface of the annular cavity (16). The hexagonal plastic elastic part (6) is provided with an annular recess (25) on the side away from the contact surface (26), and the surface of the annular recess (25) is evenly divided and provided with six spring pieces (18) that are in contact with the corresponding inclined parts (24); The inner wall surface of the core rod (2) is symmetrically provided with two limiting spring plates (8) which are inclined inwards and are used to limit and block the needle seat (5).

2. A medical safety rebound syringe according to claim 1, characterized in that: The inner wall surface of the mounting shell (23) is provided with a snap ring seat (21) for the end of the compression spring (13) to enter, and the end of the compression spring (13) is not fixedly connected to the snap ring seat (21).

3. A medical safety rebound syringe according to claim 1, characterized in that: The end of the needle seat (5) is sleeved with a mounting ring (22), the outside of the injection needle (4) is sleeved with a needle cover (3) for protection, and the needle cover (3) is in matching connection with the mounting shell (23).

4. A medical safety rebound syringe according to any one of claims 1 to 3, characterized in that: The method of using the syringe comprises the following steps: Step 1: Install the needle seat (5) into a mounting shell (23) connected to the syringe barrel (1), and use an elastic sheet (9) to clamp and fix the needle seat (5); Step 2: After the needle is installed in place, the elastic sheet (9) is pressed downwards so that the inner buckle (20) engages with the outer buckle (12), thereby fixing the needle seat (5) and injecting the liquid using the injection needle (4) in the needle seat (5); Step 3: After the injection is completed, the core rod (2) pushes the hexagonal plastic elastic member (6) and the rubber plug (7) to move together to the end position of the inner cavity of the syringe barrel (1), and the contact surface (26) of the end face of the hexagonal plastic elastic member (6) fits the pressing surface (27), and at the same time, a reverse thrust is generated on the hexagonal plastic elastic member (6) and enters the inner cavity of the core rod (2). At this time, the needle seat (5) is pushed to one side and then squeezes the elastic sheet (9) upward, so that the needle seat (5) rebounds; Step 4: During the rebound process, since the buckle restriction on the needle seat (5) is released, the compression spring (13) generates a rebound thrust from the tensioned state, pushing the needle seat (5) through the interior of the rebound seat (14) into the inner cavity of the core rod (2), and the injection needle (4) is driven by the needle seat (5) to enter the inner cavity of the core rod (2) until the needle seat (5) passes through the inclined ends of the two limiting spring plates (8).

5. A medical safety rebound syringe according to claim 4, characterized in that: In step three, under the push of the core rod (2), the rebound seat (14) drives the rubber plug (7) outside it to fit with the inner cavity end of the syringe barrel (1). At this time, the contact surface (26) on the hexagonal plastic elastic part (6) contacts the fitting surface (27) and exerts a thrust on the needle seat (5), which is pushed to one side by the outer buckle (12) and leaves the inside of the inner buckle (20), so that the elastic sheet (9) is separated from the contact with the needle seat (5) upward, and the needle seat (5) rebounds.

6. A medical safety rebound syringe according to claim 4, characterized in that: In step three, the hexagonal plastic elastic member (6) generates a reverse thrust on the hexagonal plastic elastic member (6) while pushing the needle seat (5). The spring piece (18) on the hexagonal plastic elastic member (6) is deformed by the thrust and pops out from the inclined portion (24), completing the triggering action.

7. A medical safety rebound syringe according to claim 4, characterized in that: In step 4, the hexagonal plastic elastic member (6) first passes through the interior of the rebound seat (14) and squeezes the inclined ends of the two limiting spring plates (8) out of the inner cavity of the core rod (2), and then the needle seat (5) passes through the rebound seat (14) under the rebound thrust of the compression spring (13) until it leaves the inclined ends of the limiting spring plates (8), rebounding the injection needle (4) and retaining it in the inner cavity of the core rod (2).

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