Anti-disassembly packaging structure of hardware encryption chip

Abstract

The application relates to the technical field of electronic device packaging structures, in particular to a disassembly-preventing packaging structure of a hardware encryption chip, which comprises a chip base, a protective shell, a stress conduction mechanism and a chain destruction mechanism. The stress conduction mechanism comprises a brittle conduction grid formed integrally and connected between the chip base and the protective shell; the chain destruction mechanism comprises a plurality of micro hammers and corresponding elastic energy storage pieces, which are limited by limiting contacts on the conduction grid. When the conduction grid is broken as a whole due to external force, the limiting contacts release the hammers, and the elastic energy storage pieces drive the hammers to impact the chip. The application can realize global response and chain destruction to physical disassembly.

Description

Technical Field

[0001] This utility model belongs to the field of electronic device packaging structure technology, specifically a hardware encryption chip anti-disassembly packaging structure. Background Technology

[0002] Hardware encryption chips, as a key component for ensuring information security, are widely used in finance, communications, the Internet of Things (IoT), and identity authentication. They are used to store sensitive data and perform encryption operations, and their security directly affects the confidentiality and reliability of the entire system. To ensure the physical security of hardware encryption chips, a packaging structure is typically used to isolate their core circuitry from the external environment, preventing unauthorized access or probes. Existing packaging technologies often enhance the chip's resistance to disassembly through epoxy resin potting, metal shielding, or mechanical locking, while also incorporating sensors and self-destruct mechanisms to trigger data erasure upon detecting anomalies.

[0003] However, existing hardware encryption chip packaging structures often exhibit uneven stress distribution at the interface between the protective layer and the chip body when subjected to progressive physical disassembly using precision tools. This leads to premature failure of adhesive or snap-fit ​​structures in some areas during disassembly, allowing external tools to gradually penetrate without completely destroying the packaging. Therefore, such structures have a lag in responding to continuous, low-intensity physical intrusion, affecting the immediacy and reliability of overall anti-disassembly measures. Utility Model Content

[0004] This invention provides a tamper-proof packaging structure for a hardware encryption chip. It addresses the problems of uneven stress distribution and delayed response in existing packaging structures when dealing with progressive physical disassembly by proposing a protection scheme with global stress transmission and chain response.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A tamper-proof packaging structure for a hardware encryption chip includes a chip base, a protective shell, a stress transmission mechanism, and an interlocking destruction mechanism. The chip base is used to support the hardware encryption chip. The protective shell is disposed above the chip base. The stress transmission mechanism is disposed between the chip base and the protective shell. The interlocking destruction mechanism is connected to the stress transmission mechanism and is disposed adjacent to the hardware encryption chip.

[0007] The stress transmission mechanism includes a conductive grid made of a brittle material. The conductive grid is an integrally formed mesh structure. The bottom surface of the conductive grid is fixedly connected to the top surface of the chip base, and the top surface of the conductive grid is fixedly connected to the inner bottom wall of the protective shell. The conductive grid undergoes an overall structural fracture when subjected to local external force.

[0008] The chain destruction mechanism includes multiple miniature strikers disposed on the chip base and elastic energy storage components corresponding to each miniature striker. The impact ends of the miniature strikers face the hardware encryption chip. Multiple limiting contacts are disposed on the conductive grid, and each limiting contact engages with the corresponding miniature striker. When the conductive grid breaks, the limiting contacts disengage from the miniature strikers, and the elastic energy storage components drive the miniature strikers to move and impact the hardware encryption chip.

[0009] Optionally, the top surface of the chip base is provided with an annular groove, and the bottom edge of the protective shell extends with an annular flange, the annular flange being adapted to the annular groove, and the edge region of the conductive grid filling the gap between the annular groove and the annular flange.

[0010] Optionally, the conductive grid is composed of multiple conductive nodes and connecting arms that connect the conductive nodes in an alternating manner. The cross-section of the connecting arm is a trapezoidal structure. The limiting contact is a cantilever structure extending from the conductive node. The rod of the miniature firing pin is provided with a limiting groove that engages with the cantilever structure.

[0011] Optionally, the elastic energy storage component is a compression spring. The chip base has multiple guide holes corresponding to the positions of the micro-impact pins. The rod of each micro-impact pin passes through one of the guide holes. The compression spring is sleeved on the rod of the micro-impact pin, and the two ends of the compression spring abut against the bottom of the guide hole and the outer wall of the rod of the micro-impact pin, respectively.

[0012] Optionally, the protective shell has a layered structure, including an outer rigid protective layer and an inner flexible buffer layer. The rigid protective layer is made of a high-hardness ceramic material, and the flexible buffer layer is made of a polymer material. The top surface of the conductive grid is bonded to the bottom surface of the flexible buffer layer with an adhesive.

[0013] Optionally, the connecting arm of the conductive grid also integrates a conductive path, which is a continuous serpentine metal line. The two ends of the conductive path are connected to the detection pins of the hardware encryption chip. The breakage of the conductive grid will simultaneously cut off the conductive path.

[0014] Optionally, the stress transmission mechanism further includes multiple chemical reaction microcapsules filled in the cavity of the conductive grid. Each chemical reaction microcapsule contains two mutually isolated chemical reagents. The breakage of the conductive grid will compress and destroy the capsule wall of the chemical reaction microcapsule. The two chemical reagents will react exothermically or corrode after mixing.

[0015] Optionally, the top surface of the chip substrate and the inner bottom wall of the protective shell are both machined with interlocking micro-serrated structures, and the top and bottom surfaces of the conductive grid have tooth shapes that match the micro-serrated structures. The conductive grid is fixed to the chip substrate and the protective shell by tooth engagement.

[0016] Optionally, the chain destruction mechanism further includes multiple fixing seats fixed on the chip base, the guide hole is opened in the fixing seat, and the impact end of the micro striker is a diamond tapered structure to increase the destruction depth of the silicon substrate of the hardware encryption chip.

[0017] This utility model provides a tamper-proof packaging structure for a hardware encryption chip, which has the following advantages:

[0018] The core of this hardware encryption chip's tamper-proof packaging structure lies in its integrated stress transmission mechanism. When any part of the protective shell is subjected to physical intrusion forces such as drilling or prying, the external force will directly act on the conductive grid tightly connected to it. Since the conductive grid is an integrated brittle mesh structure, the local stress will be instantly transmitted to the entire grid structure through the connecting arms and conductive nodes. Once the stress exceeds the material's fracture threshold, it will trigger a global chain fracture of the entire conductive grid, rather than a local failure. This structure transforms any form of local intrusion into damage to the overall protective structure, eliminating local weak points caused by uneven stress distribution in traditional packaging, and achieving a global response to physical intrusion. The overall fracture of the conductive grid simultaneously releases the mechanical restraints on all micro-collision pins, and the energy stored in each elastic energy storage component is released instantaneously, driving multiple micro-collision pins to simultaneously strike the chip core from different positions, performing physical destruction. Its response process is entirely based on the failure of the mechanical structure, with high immediacy and does not rely on external power supply or sensor judgment, thus improving the reliability of the destruction action. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0020] Figure 2 This is an exploded view of the tamper-proof packaging structure according to an embodiment of this application;

[0021] Figure 3This is an assembly diagram of the stress transmission mechanism and the interlocking destruction mechanism of this utility model;

[0022] Figure 4 This is a partially enlarged schematic diagram of a miniature firing pin according to an embodiment of this application;

[0023] Figure 5 This is a cross-sectional view of the connection structure between the protective shell and the chip base of this utility model;

[0024] Figure 6 This is a schematic diagram of the operation state of the chain destruction mechanism according to an embodiment of this application;

[0025] Explanation of reference numerals in the attached figures:

[0026] 1. Chip base; 2. Protective shell; 3. Stress transmission mechanism; 4. Interlocking destruction mechanism; 5. Conductive grid; 6. Miniature impact pin; 7. Elastic energy storage component; 8. Limiting contact; 9. Hardware encryption chip; 10. Annular groove; 11. Annular flange; 12. Conductive node; 13. Connecting arm; 14. Cantilever structure; 15. Limiting groove; 16. Compression spring; 17. Guide hole; 18. Hard protective layer; 19. Tough buffer layer; 20. Conductive path; 21. Chemical reaction microcapsule; 22. Microscopic serrated structure; 23. Fixing base; 24. Impact end; 25. Adhesive; 26. Inner wall of guide hole. Detailed Implementation

[0027] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0028] Please see Figures 1 to 6 This utility model provides a tamper-proof packaging structure for a hardware encryption chip. This structure is applied to the field of physical protection for hardware encryption chips. By setting an integrated stress transmission mechanism and a chain-linked physical destruction mechanism, when the packaging structure encounters external physical intrusion, it can convert local forces into a failure response of the overall structure and simultaneously trigger multi-point physical destruction actions, thereby destroying the internal data of the hardware encryption chip.

[0029] Please see Figure 1 and Figure 2This utility model provides a technical solution: a tamper-proof packaging structure for a hardware encryption chip, including a chip base 1, a protective shell 2, a stress transmission mechanism 3, and a chain destruction mechanism 4. The hardware encryption chip 9 is mounted on the top surface of the chip base 1. The protective shell 2 completely covers the chip base 1, fully accommodating the hardware encryption chip 9 within its internal space. The stress transmission mechanism 3 is disposed within the enclosed space formed by the chip base 1 and the protective shell 2, and is tightly connected to both. The chain destruction mechanism 4 has a mechanical linkage with the stress transmission mechanism 3, and the actuating component of the chain destruction mechanism 4 is arranged adjacent to the hardware encryption chip 9.

[0030] In this embodiment, the core component of the stress transmission mechanism 3 is a conductive grid 5. The conductive grid 5 is integrally molded from a brittle material, exhibiting a mesh structure. The bottom surface of the conductive grid 5 is fixedly connected to the top surface of the chip substrate 1, and the top surface of the conductive grid 5 is fixedly connected to the inner bottom wall of the protective shell 2. This structural arrangement makes the conductive grid 5 an intermediate structural layer connecting the chip substrate 1 and the protective shell 2. When any local location of the protective shell 2 is subjected to external force, the external force will be directly transmitted to the conductive grid 5 fixed to it. Due to the material properties and integrated mesh structure of the conductive grid 5, local stress will be rapidly transmitted to the entire grid structure. When the stress value exceeds the fracture threshold of the brittle material, it will cause a global structural fracture of the entire conductive grid 5, rather than just local damage at the stress point.

[0031] The chain destruction mechanism 4 includes multiple miniature strikers 6 disposed on the chip base 1 and elastic energy storage components 7 corresponding to each miniature striker 6. The impact end 24 of the miniature striker 6 faces the hardware encryption chip 9. Multiple limiting contacts 8 are integrally formed on the conductive grid 5. Each limiting contact 8 is engaged with a corresponding miniature striker 6. When the conductive grid 5 is structurally intact, the limiting contacts 8 lock the position of the miniature striker 6 and restrict its movement. When the conductive grid 5 breaks, the limiting contacts 8 break or displace, thereby releasing the engagement and limiting of the miniature striker 6. At the instant the limiting is released, the elastic energy storage component 7, in its energy storage state, releases its stored energy, driving the corresponding miniature striker 6 to move at high speed. Its impact end 24 then impacts the surface of the hardware encryption chip 9, causing irreversible physical damage.

[0032] In the above embodiments, as a preferred connection and sealing solution, please refer to... Figure 5The chip substrate 1 has an annular groove 10 formed along its outer periphery on its top surface. Correspondingly, the bottom edge of the protective shell 2 has an annular flange 11 extending downwards integrally formed. The shape and size of the annular flange 11 are adapted to the annular groove 10, and during assembly, the annular flange 11 is inserted into the annular groove 10. The edge region of the conductive grid 5 fills the gap between the annular groove 10 and the annular flange 11. This concave-convex fit structure not only enhances the bonding strength and airtightness between the chip substrate 1 and the protective shell 2, but also firmly anchors the edge portion of the conductive grid 5, establishing an effective stress transmission path from the edge of the protective shell 2 to the conductive grid 5.

[0033] In the above embodiments, for a detailed description of the linkage structure between the stress transmission mechanism 3 and the interlocking destruction mechanism 4, please refer to [link to relevant documentation]. Figure 3 and Figure 4 The conductive grid 5 is composed of multiple conductive nodes 12 and connecting arms 13 for connecting adjacent conductive nodes 12 in an alternating manner. The cross-section of the connecting arm 13 is trapezoidal. This cross-sectional shape will generate stress concentration when subjected to bending or torsional loads, which helps to accelerate the brittle fracture process of the entire structure. The specific structure of the limiting contact 8 is a cantilever structure 14 extending from part of the conductive nodes 12. The rod of the miniature striker 6 is provided with a limiting groove 15 that engages with the cantilever structure 14. In the initial state, the end of the cantilever structure 14 is engaged in the limiting groove 15, locking the miniature striker 6 through mechanical engagement. When the conductive grid 5 breaks, the connecting arm 13 or the conductive node 12 connected to the cantilever structure 14 breaks, causing the cantilever structure 14 to lose support and break or deflect, eventually disengaging from the limiting groove 15 and releasing the miniature striker 6.

[0034] In the above embodiments, the energy storage and guiding structure of the interlocking destruction mechanism 4 is further defined. Please refer to [link to relevant documentation]. Figure 3 and Figure 6The elastic energy storage component 7 is specifically a compression spring 16. The chip base 1 has multiple guide holes 17, the positions of which correspond one-to-one with the positions of the micro-firing pins 6. The rod portion of each micro-firing pin 6 passes through a corresponding guide hole 17, and the inner wall 26 of the guide hole 17 guides the reciprocating motion of the micro-firing pin 6. The compression spring 16 is sleeved on the rod of the micro-firing pin 6, with its two ends abutting against the bottom of the guide hole 17 and the outer wall of a protruding structure on the rod of the micro-firing pin 6, respectively. During assembly, the micro-firing pin 6 is pulled backward until its limiting groove 15 engages with the cantilever structure 14 of the conduction grid 5. During this process, the compression spring 16 is compressed, storing mechanical energy within it.

[0035] In the above embodiments, as a preferred structural design of the protective shell 2, the protective shell 2 adopts a layered structure design, which includes an outer rigid protective layer 18 and an inner flexible buffer layer 19. The rigid protective layer 18 is made of a high-hardness ceramic material, whose high hardness characteristics can resist physical intrusion such as drilling and cutting. The flexible buffer layer 19 is made of a polymer material, which can absorb some of the impact energy, and its bottom surface is bonded to the top surface of the conductive grid 5 by an adhesive 25. When an external force breaks through the rigid protective layer 18, it acts on the flexible buffer layer 19. The deformation of the flexible buffer layer 19 will directly pull or compress the conductive grid 5 bonded to it, thereby effectively transmitting the external force to the stress transmission mechanism 3.

[0036] In the above embodiment, to add another dimension of protection response, a conductive path 20 is also integrated inside the connecting arm 13 of the conductive grid 5. The conductive path 20 is a continuous serpentine metal line whose wiring path runs through most of the entire conductive grid 5. The two ends of the conductive path 20 are led out and connected to specific detection pins of the hardware encryption chip 9. Under normal conditions, the conductive path 20 is in a conductive state. When the conductive grid 5 experiences a structural fracture, the connecting arm 13 constituting the grid breaks, which will inevitably cut off the internally integrated conductive path 20 simultaneously, changing the voltage level of the detection pin. This voltage level change can serve as a signal to trigger the self-destruct logic inside the hardware encryption chip 9.

[0037] In the above embodiment, to further enhance the destruction effect, the stress transmission mechanism 3 also includes multiple chemical reaction microcapsules 21 filled within the grid cavities of the conduction grid 5. Each chemical reaction microcapsule 21 encapsulates two or more physically isolated chemical reagents. When the conduction grid 5 breaks, fragments of the broken connecting arm 13 and conduction node 12 compress and destroy the walls of the surrounding chemical reaction microcapsules 21. After the capsule walls rupture, the two previously isolated chemical reagents mix and rapidly undergo an exothermic or corrosive reaction. The resulting high-temperature or corrosive substances directly act on the underlying hardware encryption chip 9, chemically damaging its physical structure and internal circuitry.

[0038] In the above embodiments, to enhance the mechanical coupling between the conductive grid 5, the chip substrate 1, and the protective shell 2, the top surface of the chip substrate 1 and the inner bottom wall of the protective shell 2 are both machined with interlocking micro-serrated structures 22. Correspondingly, the top and bottom surfaces of the conductive grid 5 also have tooth profiles matching the micro-serrated structures 22. During assembly, the tooth profiles of the conductive grid 5 are interlocked and fixed with the micro-serrated structures 22 on the chip substrate 1 and the protective shell 2. Compared with planar adhesive bonding, this toothed interlocking connection provides higher shear strength, eliminates the possibility of interface slippage under external force, and ensures that minute displacements in any direction can be transmitted to the conductive grid 5 without damage.

[0039] In the above embodiment, to improve the execution efficiency of the chain destruction mechanism 4, the mechanism also includes multiple fixing seats 23 fixed on the chip base 1. The guide hole 17 is formed inside these fixing seats 23. By setting the fixing seats 23, the depth and angle of the guide hole 17 can be controlled more precisely, thereby optimizing the movement trajectory of the micro-impact pin 6. In addition, the impact end 24 of the micro-impact pin 6 is specifically a conical structure made of diamond. The high hardness of diamond combined with the sharp conical structure can generate extremely high pressure on the silicon substrate of the hardware encryption chip 9 upon impact, thereby causing deeper penetration and a wider fracture area, increasing the degree of physical damage to the precision circuits inside the chip.

[0040] In this invention, the working steps of the device are as follows:

[0041] 1. When the encapsulation structure is intact, the protective shell 2 protects the internal hardware encryption chip 9. The conductive grid 5, as an integrated structure, has all its limiting contacts 8 reliably engaged with the limiting slots 15 of the corresponding miniature firing pins 6. Each miniature firing pin 6 is locked in a ready-to-fire position with the elastic energy storage element 7 compressed. The conductive path 20 inside the conductive grid 5 remains electrically connected.

[0042] 2. When external physical intrusion, such as drilling or prying, is applied to any local location of the protective shell 2, the force is directly transmitted to the corresponding area of ​​the conductive grid 5 through the tough buffer layer 19 and the micro-serrated structure 22 of the protective shell 2.

[0043] Third, because the conductive grid 5 is made of a brittle material and has an integrated mesh structure, local stress can rapidly spread to the entire grid through the connecting arm 13 and the conductive node 12. Once the stress exceeds the material's fracture limit, the conductive grid 5 will experience a global, cascading brittle fracture.

[0044] Fourth, the breakage of the conductive grid 5 will simultaneously trigger multiple events: First, the connecting arm 13 constituting the grid breaks, resulting in the internal integrated conductive path 20 being cut off; second, the fragments of the broken grid squeeze and puncture the chemical reaction microcapsules 21 filled in its grid cavity, causing the internal chemical reagents to mix and react; third, and most importantly, the breakage of the conductive grid 5 destroys all the limiting contacts 8 in the form of cantilever structures 14 on it, causing them to dislodge from the limiting grooves 15 of all the micro-firing pins 6.

[0045] 5. With the failure of all limit contacts 8, the previously compressed elastic energy storage element 7 (i.e., compression spring 16) instantly releases its stored elastic energy, driving all the micro-impact pins 6 to be ejected at high speed along their respective guide holes 17. Their diamond impact ends 24 simultaneously strike the surface of the hardware encryption chip 9 from multiple different positions and angles, causing large-area physical breakage. At the same time, the chemical substances released by the chemical reaction microcapsules 21 perform secondary chemical destruction on the chip.

Claims

1. A tamper-proof packaging structure for a hardware encryption chip, characterized in that: The device includes a chip base (1), a protective shell (2), a stress transmission mechanism (3), and a chain destruction mechanism (4). The chip base (1) is used to support the hardware encryption chip (9). The protective shell (2) covers the chip base (1). The stress transmission mechanism (3) is disposed between the chip base (1) and the protective shell (2). The chain destruction mechanism (4) is connected to the stress transmission mechanism (3) and is disposed adjacent to the hardware encryption chip (9). The stress transmission mechanism (3) includes a conductive grid (5) made of brittle material. The conductive grid (5) is an integrally formed mesh structure. The bottom surface of the conductive grid (5) is fixedly connected to the top surface of the chip base (1). The top surface of the conductive grid (5) is fixedly connected to the inner bottom wall of the protective shell (2). The conductive grid (5) undergoes an overall structural fracture when subjected to local external force. The chain destruction mechanism (4) includes multiple miniature strikers (6) disposed on the chip base (1) and elastic energy storage components (7) corresponding to each miniature striker (6). The impact end (24) of the miniature striker (6) faces the hardware encryption chip (9). Multiple limiting contacts (8) are disposed on the conduction grid (5). Each limiting contact (8) is respectively engaged with the corresponding miniature striker (6). When the conduction grid (5) breaks, the limiting contact (8) disengages from the miniature striker (6), and the elastic energy storage component (7) drives the miniature striker (6) to move to impact the hardware encryption chip (9).

2. The anti-tampering packaging structure of a hardware encryption chip according to claim 1, characterized in that: The chip base (1) has an annular groove (10) on its top surface, and the bottom edge of the protective shell (2) has an annular flange (11) that is adapted to the annular groove (10). The edge area of ​​the conductive grid (5) is filled in the gap between the annular groove (10) and the annular flange (11).

3. The anti-tampering packaging structure of a hardware encryption chip according to claim 1, characterized in that: The conductive grid (5) is composed of multiple conductive nodes (12) and connecting arms (13) connecting the conductive nodes (12) in an alternating manner. The cross-section of the connecting arm (13) is a trapezoidal structure. The limiting contact (8) is a cantilever structure (14) extending from the conductive node (12). The rod of the miniature striker (6) is provided with a limiting groove (15) that engages with the cantilever structure (14).

4. The anti-tampering packaging structure of a hardware encryption chip according to claim 1, characterized in that: The elastic energy storage component (7) is a compression spring (16). The chip base (1) has multiple guide holes (17) corresponding to the positions of the micro-firing pins (6). The rod of each micro-firing pin (6) passes through one of the guide holes (17). The compression spring (16) is sleeved on the rod of the micro-firing pin (6). The two ends of the compression spring (16) abut against the bottom of the guide hole (17) and the outer wall of the rod of the micro-firing pin (6), respectively.

5. The anti-tampering packaging structure of a hardware encryption chip according to claim 1, characterized in that: The protective shell (2) has a layered structure, including an outer hard protective layer (18) and an inner tough buffer layer (19). The hard protective layer (18) is made of high-hardness ceramic material, and the tough buffer layer (19) is made of polymer material. The top surface of the conductive grid (5) and the bottom surface of the tough buffer layer (19) are bonded together by adhesive (25).

6. The anti-tampering packaging structure of a hardware encryption chip according to claim 1, characterized in that: The conductive grid (5) has an integrated conductive path (20) inside the connecting arm (13). The conductive path (20) is a continuous serpentine metal line. The two ends of the conductive path (20) are connected to the detection pins of the hardware encryption chip (9).

7. The anti-tampering packaging structure of a hardware encryption chip according to claim 1, characterized in that: The stress transmission mechanism (3) also includes a plurality of chemical reaction microcapsules (21) filled in the grid cavity of the conduction grid (5). Each chemical reaction microcapsule (21) encapsulates two mutually isolated chemical reagents. The breakage of the conduction grid (5) destroys the capsule wall of the chemical reaction microcapsule (21), causing the two chemical reagents to mix and react.

8. The anti-tampering packaging structure of a hardware encryption chip according to claim 1, characterized in that: The top surface of the chip base (1) and the inner bottom wall of the protective shell (2) are both machined with interlocking micro-serrated structures (22). The top and bottom surfaces of the conductive grid (5) have tooth shapes that match the micro-serrated structures (22). The conductive grid (5) is fixed to the chip base (1) and the protective shell (2) by tooth meshing.

9. The anti-tampering packaging structure of a hardware encryption chip according to claim 4, characterized in that: The chain destruction mechanism (4) also includes multiple fixing seats (23) fixed on the chip base (1), the guide hole (17) is opened in the fixing seat (23), and the impact end (24) of the micro striker (6) is a diamond conical structure.

10. The anti-tampering packaging structure of a hardware encryption chip according to claim 3, characterized in that: The cantilever structure (14) is engaged in the limiting groove (15). When the conductive grid (5) breaks, the cantilever structure (14) disengages from the limiting groove (15) and releases the miniature impact pin (6).

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