Impact head connecting device

Abstract

The invention discloses an impact head connecting device, and relates to the technical field of impact test devices, the impact head connecting device comprises a guide piece, a connecting piece and an impact fracture piece, the guide piece is fixedly mounted at the end of an impact rod for providing impact power, a guide hole is formed in the guide piece in the impact direction, one end of the connecting piece is fixedly connected with an impact head for impact, and the other end of the connecting piece is fixedly connected with the impact fracture piece. The end, away from the impact head, of the connecting piece is provided with a guide part, the guide part penetrates through the guide hole and is in sliding connection with the guide hole, the guide part is provided with a containing hole in the axial direction, and a pressing head of the impact fracture piece presses the connecting piece to abut against the guide piece. The impact fracture piece on the impact head connecting device can be stretched and instantly fractured under the action of huge inertia force of the impact head, so that the impact head and the impact rod are automatically separated, the impact head freely impacts a test object, and the effect of simulating free impact is achieved.

Description

Technical Field

[0001] This application relates to the technical field of impact test devices, and particularly to an impact head connection device. Background Art

[0002] For large-scale impact test equipment, its impact speed and impact energy are very large. If the impact rod directly strikes the object to be tested with the impact head, it is easy to damage the equipment, and it is not easy to accurately measure the impact energy and impact parameters. For test equipment that needs to simulate the free impact working condition, achieving free impact is essential.

[0003] For the high-speed impact process, the entire process only takes dozens of milliseconds. Conventional mechanisms are difficult to instantaneously and reliably actively implement the impact head disconnection operation within such a short time. If the impact head cannot be reliably disconnected by itself, it will seriously affect the impact action effect and equipment safety.

[0004] As a test equipment, in addition to achieving reliable self-disconnection during the high-speed impact process, it is also necessary to control the flight attitude of the impact head to remain unchanged during the free flight process after the impact head detaches from the impact rod, so that the impact head can strike the object to be tested in the required attitude of the test.

[0005] Therefore, how to enable the impact head to disconnect from the impact rod by itself and maintain the flight attitude unchanged is a technical problem that needs to be solved by those skilled in the art currently. Summary of the Invention

[0006] In order to help solve the above technical problems, this application provides an impact head connection device.

[0007] An impact head connection device includes a guide member, a connecting member, and an impact fracture member. The guide member is fixedly installed at the end of an impact rod for providing impact power. The guide member is provided with a guide hole in the direction of impact. One end of the connecting member is fixedly connected to an impact head for impact. The other end of the connecting member away from the impact head is provided with a guide portion. The guide portion passes through the guide hole and is slidably connected to the guide hole. The guide portion is axially provided with a receiving hole. One end of the impact fracture member is provided with a screw rod, and the other end is provided with a pressing head. The screw rod passes through the receiving hole and is threadedly fixed to the guide member. The pressing head presses the connecting member against the guide member.

[0008] By adopting the above technical solution, the impact rod in the impact cylinder is connected to the impact head through the guide piece, the connecting piece and the impact fracture piece, so that the impact head can complete the impact preparation return stroke action and the impact action together with the impact rod. When the impact rod reaches the end of the impact acceleration stroke and deceleration buffer control is carried out, the impact fracture piece on the impact head connecting device will be stretched and instantaneously fractured under the action of the huge inertia force of the impact head, so that the impact head is automatically disconnected from the impact rod, realizing the automatic separation of the effective impact load, and at the same time keeping the free impact posture of the impact head stable. Then the impact head freely impacts the test object, achieving the effect of simulating free impact.

[0009] Preferably, the guide piece includes a cup body, an external thread for fixedly connecting with the impact rod by thread is arranged on the outer wall of the cup body, the inner wall of the cup body is the guide hole, and an internal thread hole for threadedly connecting with the lead screw is arranged at the bottom of the cup body of the cup body.

[0010] By adopting the above technical solution, the guide piece is fixedly connected with the impact rod by thread through the external thread on the cup body, the guiding part of the connecting piece is guided through the guide hole, the internal thread hole on the bottom of the cup body of the cup body is used for fixedly connecting with the lead screw of the impact fracture piece, the impact fracture piece fractures under the action of the impact force, and the connecting piece still keeps the flying posture before flying under the guiding of the guiding part in the guide hole, which helps to improve the effect of the impact head impacting the test object.

[0011] Preferably, a butt flange is arranged at one end of the cup body close to the cup mouth, one end of the butt flange close to the connecting piece is in pressing butt joint with the connecting piece, and one end of the butt flange far from the connecting piece is in pressing butt joint with the impact rod.

[0012] By adopting the above technical solution, a butt flange is arranged on the cup mouth of the cup body, one end of the butt flange is in butt joint with the connecting piece, and the other end is in butt joint with the impact rod, improving the reliability of the butt joint between the connecting piece and the impact rod, and helping the butt flange to evenly transfer the impact force of the impact rod to the connecting piece, so that the connecting piece and the impact head always keep the same posture before and after flying.

[0013] Preferably, the connecting piece includes a sleeve body coaxially arranged with the guiding part, a connecting flange for connecting the impact head is arranged at one end of the sleeve body, a pressing flange for pressing the butt flange is arranged at the other end, the guiding part is arranged at one end of the pressing flange far from the sleeve body, and a through hole for passing through the lead screw is arranged on the pressing flange.

[0014] By adopting the above technical solution, the connecting piece is fixedly connected with the impact head through the connecting flange, is pressed on the butt flange through the pressing flange, and the pressing flange is provided with a through hole, which is convenient for installing the impact fracture piece into the internal thread hole of the guide piece, so as to press and install the connecting piece in the guide piece, improving the convenience of installation.

[0015] Preferably, a plurality of operation holes for installing the impact fracture member are provided on the sleeve body, and the plurality of operation holes are uniformly arranged along the circumferential direction of the sleeve body.

[0016] By adopting the above technical solution, a plurality of operation holes are provided on the sleeve body, which facilitates the installation of the impact fracture member onto the guiding member through the operation holes, improving the convenience of the installation operation. The operation holes are uniformly arranged along the circumferential direction of the sleeve body, which helps to ensure the consistency of the strength of the outer wall of the sleeve body and improves the reliability of the connecting member during impact work.

[0017] Preferably, a positioning platform extending outward along the axis of the sleeve body is provided at one end of the connecting flange away from the sleeve body, and the positioning platform is used for radially positioning the impact head; a plurality of mounting holes are provided circumferentially on the connecting flange, and fastening screws are installed in the mounting holes to press and fix the impact head at one end of the connecting flange close to the impact head.

[0018] By adopting the above technical solution, the connecting flange radially positions the impact head through the positioning platform to ensure that the center of gravity of the impact head and the center of gravity of the connecting member are both located on the axis of the sleeve body. The impact head is pressed and fixed on the connecting flange by the fastening screws installed in the mounting holes, improving the reliability of the connection. After the impact fracture member breaks, since the center of gravity of the impact head and the center of gravity of the connecting member are both located on the axis of the sleeve body coaxial with the guiding portion, it helps the connecting member and the impact head to be connected together and maintain the same attitude before and after flight.

[0019] Preferably, the impact fracture member further includes a rod body connected to the pressing head, and a reduced-diameter portion is provided between the rod body and the screw rod. Both ends of the reduced-diameter portion are connected to the screw rod and the rod body respectively through transition portions with diameters gradually decreasing towards the reduced-diameter portion.

[0020] By adopting the above technical solution, by providing a reduced-diameter portion between the rod body and the screw rod, and the reduced-diameter portion is connected to the screw rod and the rod body through transition portions with diameters gradually decreasing towards the reduced-diameter portion. In this way, the diameter of the reduced-diameter portion is smaller than the diameters of the screw rod and the rod body. The impact fracture member can not only bear the load of the weights of the impact head and the connecting member, but also, in the state where the impact head impacts, the reduced-diameter portion can reliably break due to the minimum bearing capacity, which helps to improve the impact effect of the impact test.

[0021] Preferably, the reduced-diameter portion of the impact fracture member includes at least two levels of first reduced-neck portions and second reduced-neck portions with decreasing diameters, and an annular stress groove is provided on the surface of the second reduced-neck portion.

[0022] By adopting the above technical solution, the reduced-diameter portion includes at least two levels of first reduced-neck portions and second reduced-neck portions with decreasing diameters, and an annular stress groove is provided on the surface of the second reduced-neck portion. The provision of the annular stress groove on the second reduced-neck portion helps to improve the reliability of the reduced-diameter portion breaking during impact.

[0023] Preferably, the impact fracture member is made of a brittle metal material.

[0024] By adopting the above technical solution, the impact fracture member is made of a brittle metal material, which helps the impact fracture member to be able to bear the load of the impact head and the connecting member before impact, and at the same time can reliably fracture under the state of the impact head impacting, which helps to improve the test effect of the impact test.

[0025] In summary, the present application includes at least one of the following beneficial technical effects: 1. The connection of the impact head connecting device to the impact rod and the impact head solves the problem that it is difficult for large-scale impact test equipment to instantaneously and reliably actively perform the impact head disconnection operation action within such a short time during the high-speed impact process, realizes the reliable self-disconnection of the impact head, and keeps the flight attitude unchanged during the free flight process after separating from the impact rod, meeting the requirement of impacting the test object in the attitude required by the large-scale impact test equipment; 2. The guide member is fixedly connected to the impact rod by threads, guides the guiding portion of the connecting member through the guiding hole, the internal threaded hole on the bottom of the cup body of the cup is used for fixedly connecting with the lead screw of the impact fracture member, the impact fracture member fractures under the action of the impact force, and the connecting member still keeps the flight attitude before flight under the guidance of the guiding portion in the guiding hole, which helps to improve the effect of the impact head impacting the test object; 3. The connecting member is fixedly connected to the impact head through the connecting flange, is pressed on the abutting flange through the pressing flange, and the pressing flange is provided with a through hole, which is convenient for installing the impact fracture member into the internal threaded hole of the guide member, so as to press and install the connecting member in the guide member, improving the convenience of installation; 4. The impact fracture member is provided with a reduced diameter portion, and the diameter of the reduced diameter portion is smaller than the diameters of the lead screw and the rod body, which helps the impact fracture member to be able to bear the load of the impact head and the connecting member, and can reliably fracture due to the minimum bearing capacity of the reduced diameter portion under the state of the impact head impacting, thereby improving the impact effect of the impact test. Description of the Drawings

[0026] Figure 1 It is a sectional view of an impact head connecting device disclosed in an embodiment of the present application.

[0027] Figure 2 It is a sectional view of the guide member disclosed in an embodiment of the present application.

[0028] Figure 3 It is a sectional view of the connecting member disclosed in an embodiment of the present application.

[0029] Figure 4 It is a structural schematic diagram of the impact fracture member disclosed in an embodiment of the present application.

[0030] Figure 5For Figure 4 Partial enlarged view at position I in

[0031] Description of reference numerals: 1. Guide member; 11. Cup body; 111. External thread; 112. Guide hole; 113. Internal threaded hole; 12. Contact flange; 2. Connecting member; 21. Sleeve body; 211. Operation hole; 22. Connecting flange; 221. Positioning table; 222. Mounting hole; 23. Compression flange; 231. Through hole; 24. Guide portion; 241. Accommodating hole; 3. Impact fracture member; 31. Lead screw; 32. Compression head; 33. Rod body; 34. Reduced diameter portion; 341. First reduced neck portion; 342. Second reduced neck portion; 3421. Annular stress groove; 35. Transition portion; 4. Fastening screw; 5. Impact rod; 6. Impact head. Detailed implementation manners

[0032] The following is a further detailed description of the present application in conjunction with Figures 1 to 5 the present application.

[0033] An embodiment of the present application discloses an impact head connection device.

[0034] An impact head connection device. Referring to Figure 1 and Figure 2 , it includes a guide member 1, a connecting member 2 and an impact fracture member 3. The guide member 1 is fixedly installed at the end of an impact rod 5 for providing impact power. The guide member 1 is provided with a guide hole 112 in the impact direction. One end of the connecting member 2 is fixedly connected to an impact head 6 for impact. The end of the connecting member 2 away from the impact head 6 is provided with a guide portion 24. The guide portion 24 passes through the guide hole 112 and is slidably connected to the guide hole 112. The guide portion 24 is axially provided with an accommodating hole 241. One end of the impact fracture member 3 is provided with a lead screw 31, and the other end is provided with a compression head 32. The lead screw 31 passes through the accommodating hole 241 and is threadedly fixed to the guide member 1. The compression head 32 presses the connecting member 2 against the guide member 1. The impact rod 5 in the impact cylinder is connected to the impact head 6 through the guide member 1, the connecting member 2 and the impact fracture member 3, so that the impact head 6 can complete the impact preparation return action and the impact action together with the impact rod 5. When the impact rod 5 reaches the end of the impact acceleration stroke and performs deceleration and buffering control, the impact fracture member 3 on the impact head connection device will be stretched and instantaneously fractured under the huge inertial force of the impact head 6, so that the impact head 6 is automatically disconnected from the impact rod 5, realizing the automatic separation of the effective impact load, and at the same time maintaining the stable free impact posture of the impact head 6. Then the impact head 6 freely impacts the test object, achieving the effect of simulating a free impact.

[0035] Referring to Figure 2, the guiding member 1 includes a cup body 11. An external thread 111 for threadedly fixing to the impact rod 5 is provided on the outer wall of the cup body 11. The inner wall of the cup body 11 is a guiding hole 112, and the guiding hole 112 is coaxially arranged with the impact rod 5. An internal threaded hole 113 is provided at the bottom of the cup body 11 of the cup body 11. The lead screw 31 passes through the internal threaded hole 113 and is threadedly fixed to the bottom of the cup body 11 of the cup body 11. The guiding member 1 is threadedly fixed to the impact rod 5 through the external thread 111 on the cup body 11, guides the guiding portion 24 of the connecting member 2 through the guiding hole 112, and the internal threaded hole 113 on the bottom of the cup body 11 of the cup body 11 is used for threadedly fixing to the lead screw 31 of the impact breaking member 3. The impact breaking member 3 breaks under the action of impact force. The connecting member 2 maintains its flight attitude before flight through the guiding of the guiding portion 24 in the guiding hole 112, which helps to improve the effect of the impact head 6 hitting the test object.

[0036] Refer to Figure 2 , at one end of the cup body 11 near the cup mouth, there is an abutting flange 12. One end of the abutting flange 12 close to the connecting member 2 is in pressing abutment with the connecting member 2, and the other end of the abutting flange 12 far from the connecting member 2 is in pressing abutment with the impact rod 5. The abutting flange 12 is provided on the cup mouth of the cup body 11. One end of the abutting flange 12 abuts against the connecting member 2, and the other end abuts against the impact rod 5, which improves the reliability of the abutment between the connecting member 2 and the impact rod 5, and helps the abutting flange 12 evenly transmit the impact force of the impact rod 5 to the connecting member 2, so that the connecting member 2 and the impact head 6 always maintain the same attitude before and after flight.

[0037] Refer to Figure 2 and Figure 3 , the connecting member 2 includes a sleeve body 21. The sleeve body 21 is coaxially arranged with the guiding portion 24. One end of the sleeve body 21 is provided with a connecting flange 22 for connecting the impact head 6, and the other end is provided with a pressing flange 23 for pressing and abutting against the abutting flange 12. The guiding portion 24 is arranged at one end of the pressing flange 23 far from the sleeve body 21. A through hole 231 for passing the lead screw 31 is provided on the pressing flange 23; the connecting member 2 is fixedly connected to the impact head 6 through the connecting flange 22, is pressed on the abutting flange 12 through the pressing flange 23, and the pressing flange 23 is provided with a through hole 231, which is convenient for installing the impact breaking member 3 into the internal threaded hole 113 of the guiding member 1, so as to press and install the connecting member 2 in the guiding member 1, improving the convenience of installation. It should be noted that a light hole is provided on the pressing flange 23, and a threaded hole adapted to the light hole is provided on the abutting flange 12. During the impact preparation process, the abutting flange 12 and the pressing flange 23 are temporarily fixed by screws to prevent the impact breaking member 3 from being damaged during the impact preparation process. The fixing screws between the abutting flange 12 and the pressing flange 23 are removed in advance before starting the impact, improving the safety of the impact breaking member 3 during the impact preparation work.

[0038] Refer to Figure 3, a plurality of operation holes 211 for installing the impact fracture member 3 are provided on the sleeve body 21, and the plurality of operation holes 211 are uniformly arranged along the circumferential direction of the sleeve body 21; in the embodiment of the present application, two operation holes 211 are provided on the sleeve body 21, and the number of operation holes 211 in other embodiments of the present application is 4. Any number that can meet the convenient installation of the impact fracture member 3 and at the same time does not affect the connection strength of the connecting member 2 can be selected and used. By providing the operation holes 211, it is convenient to install the impact fracture member 3 onto the guiding member 1, improving the convenience of the installation operation. The operation holes 211 are uniformly arranged along the circumferential direction of the sleeve body 21, which helps to ensure the consistency of the outer wall strength of the sleeve body 21, and at the same time prevents the weight offset of the connecting member 2 from affecting the flight attitude during impact, improving the reliability of the connecting member 2 during impact work.

[0039] Referring to Figure 3 , at one end of the connecting flange 22 away from the sleeve body 21, a positioning table 221 extending outward along the axis of the sleeve body 21 is provided, and the positioning table 221 is used for radially positioning the impact head 6; the center of gravity of the impact head 6 coincides with the axis of the positioning table 221, the positioning table 221 is coaxially arranged with the guiding portion 24, the center of gravity of the connecting member 2 is arranged on the axis of the guiding portion 24 and the positioning table 221, and a plurality of mounting holes 222 are circumferentially distributed on the connecting flange 22. Fastening screws 4 are installed in the mounting holes 222 to press and fix the impact head 6 at one end of the connecting flange 22 close to the impact head 6. The connecting flange 22 positions the impact head 6 through the positioning table 221, and by installing the fastening screws 4 in the mounting holes 222, the impact head 6 is pressed and fixed on the connecting flange 22, improving the connection reliability. After the impact fracture member 3 fractures, it helps the connecting member 2 and the impact head 6 to be connected together and maintain the same attitude before and after flight.

[0040] Referring to Figure 4, the impact fracture member 3 is further provided with a rod body 33 connected to the pressing head 32. A reduced-diameter portion 34 is provided between the rod body 33 and the lead screw 31. Both ends of the reduced-diameter portion 34 are connected to the lead screw 31 and the rod body 33 respectively through transition portions 35 whose diameters gradually decrease towards the reduced-diameter portion 34. In the embodiment of the present application, the pressing head 32 is an internal hexagonal head, and in other embodiments of the present application, it is an external hexagonal head. The pressing head is an external hexagonal head or an internal hexagonal head, which facilitates rotating the pressing head 32 with an external hexagonal wrench or an internal hexagonal wrench and pressing the connecting member 2 onto the guiding member 1, improving the convenience of the installation operation. By providing the reduced-diameter portion 34 between the rod body 33 and the lead screw 31, and the reduced-diameter portion 34 is connected to the lead screw 31 and the rod body 33 through the transition portions 35 whose diameters gradually decrease towards the reduced-diameter portion 34. In this way, the diameter of the reduced-diameter portion 34 is smaller than the diameters of the lead screw 31 and the rod body 33. The reduced-diameter portion 34 is the part with the smallest strength of the impact fracture member 3. At the same time, the reduced-diameter portion 34 of the impact fracture member 3 can bear the load of the sum of the weights of the impact head 6 and the connecting member 2, ensuring that it does not break during the preparation before the impact head 6 impacts, and can reliably break under the impact state of the impact head 6 because the bearing capacity of the reduced-diameter portion 34 is the smallest, which helps to improve the impact effect of the impact test.

[0041] Refer to Figure 4 and Figure 5 , the reduced-diameter portion 34 of the impact fracture member 3 includes at least two levels of first reduced-neck portions 341 and second reduced-neck portions 342 with decreasing diameters. A circumferential stress groove 3421 is provided on the surface of the second reduced-neck portion 342. The circumferential stress groove 3421 is provided on the second reduced-neck portion 342, which helps to improve the reliability of the fracture of the reduced-diameter portion 34 during impact.

[0042] Refer to Figure 1 , the impact fracture member 3 is made of a brittle metal material; the impact fracture member 3 is made of a brittle metal material. It should be noted that the brittle metal material can be selected from cast iron or aluminum materials, and any metal material that can meet brittle fracture can be used. The impact fracture member 3 is made of a brittle metal material, which helps the impact fracture member 3 to be able to bear the load of the weights of the impact head 6 and the connecting member 2 before impact, and at the same time can reliably and quickly break away under the impact state of the impact head 6, which helps to improve the test effect of the impact test.

[0043] The implementation principle of an impact head connection device in an embodiment of the present application is as follows: Connect the impact head 6 to the positioning table 221 of the connecting member 2. Align the mounting hole 222 with the threaded hole of the impact head 6. Install the fastening screw 4 in the mounting hole 222. Tighten the fastening screw 4 to fix the impact head 6 to the connecting member 2. Rotate the guiding member 1 and install the guiding member 1 into the threaded hole at the end of the impact rod 5. Pass the guiding portion 24 of the connecting member 2 through the guiding hole 112, and make the pressing flange 23 abut against the abutting flange 12. Insert the impact fracture member 3 into the through hole 231 from the operation hole 211, and screw the lead screw 31 into the internal threaded hole 113 to make the pressing head 32 press the pressing flange 23, preparing for the impact test.

[0044] The above are all the preferred embodiments of the present application, and do not limit the protection scope of the present application in sequence. Therefore, all equivalent changes made according to the structure, shape, and principle of the present application should be covered within the protection scope of the present application.

Claims

1. An impact head connection device, characterized in that: The invention comprises a guide member (1), a connecting member (2) and an impact breaking member (3), wherein the guide member (1) is fixedly mounted on the end of an impact rod (5) for providing impact power, the guide member (1) is provided with a guide hole (112) in the direction of impact, one end of the connecting member (2) is fixedly connected to an impact head (6) for impact, the end of the connecting member (2) away from the impact head (6) is provided with a guide portion (24), the guide portion (24) passes through the guide hole (112) and is slidably connected to the guide hole (112), the guide portion (24) is axially provided with a receiving hole (241), one end of the impact breaking member (3) is provided with a screw rod (31), and the other end is provided with a clamping head (32), the screw rod (31) passes through the receiving hole (241) and is threadedly fixed to the guide member (1), and the clamping head (32) presses the connecting member (2) against the guide member (1).

2. An impact head connection device according to claim 1, characterized in that: The guide member (1) comprises a cup body (11), the outer wall of the cup body (11) is provided with an external thread (111) for threadedly fixing with the impact rod (5), the inner wall of the cup body (11) is the guide hole (112), and the bottom of the cup body (11) is provided with an internal thread hole (113) threadedly connected with the screw rod (31).

3. An impact head connection device according to claim 2, characterized in that: An abutment flange (12) is provided at one end of the cup body (11) close to the cup mouth, and the end of the abutment flange (12) close to the connecting piece (2) is pressed and abutted against the connecting piece (2), and the end of the abutment flange (12) away from the connecting piece (2) is pressed and abutted against the impact rod (5).

4. An impact head connection device according to claim 3, characterized in that: The connecting member (2) comprises a sleeve (21) coaxially arranged with the guide portion (24); one end of the sleeve (21) is provided with a connecting flange (22) for connecting to the impact head (6); the other end is provided with a clamping flange (23) for clamping the abutting flange (12); the guide portion (24) is arranged at one end of the clamping flange (23) away from the sleeve (21); and the clamping flange (23) is provided with a through hole (231) for passing the screw rod (31).

5. An impact head connection device according to claim 4, characterized in that: The sleeve body (21) is provided with a plurality of operating holes (211) for installing the impact breaking piece (3), and the plurality of operating holes (211) are evenly arranged along the circumference of the sleeve body (21).

6. An impact head connection device according to claim 5, characterized in that: A positioning platform (221) extending outwardly along the axis of the sleeve (21) is provided at one end of the connecting flange (22) away from the sleeve (21), and the positioning platform (221) is used to radially position the impact head (6); a plurality of mounting holes (222) are distributed circumferentially on the connecting flange (22), and fastening screws (4) are installed in the mounting holes (222) to press and fix the impact head (6) to one end of the connecting flange (22) close to the impact head (6).

7. The impact head connection device according to claim 1, characterized in that: The impact rupture member (3) is further provided with a rod body (33) connected to the clamping head (32), a reduced diameter portion (34) is provided between the rod body (33) and the screw rod (31), and two ends of the reduced diameter portion (34) are respectively connected to the screw rod (31) and the rod body (33) via transition portions (35) whose diameters gradually decrease toward the reduced diameter portion (34).

8. An impact head connection device according to claim 7, characterized in that: The reduced diameter portion (34) of the impact fracture piece (3) comprises a first reduced diameter portion (341) and a second reduced diameter portion (342) of at least two stages, wherein the surface of the second reduced diameter portion (342) is provided with an annular stress groove (3421).

9. The impact head connection device according to claim 1, characterized in that: The impact fracture piece (3) is made of a brittle metal material.

Images