A threaded spring ejector pin

Abstract

The present invention discloses a threaded spring ejector pin, comprising: a threaded shell, a spring, an ejector pin and a lock. The assembly height of the threaded spring ejector pin can be adjusted at any time by means of the threaded shell, and the pressure provided by the spring at different points can be adjusted to meet different production environments. At the same time, springs of different materials and sizes can be selected to achieve overall and large-scale pressure adjustment. In order to better adapt to springs of different sizes, the side where the ejector pin connects to the spring is designed as a self-centering conical structure to ensure that springs of different sizes can provide stable axial pressure. The present invention has a simple structure and is easy to use. It can solve the problem of poor diffusion of molten solder due to surface tension, and can apply pressure to the workpiece to be welded so as to discharge bubbles in the solder, thereby reducing the void rate of chip welding. At the same time, the spring pressure can be adjusted by means of external threads to adapt it to different workpieces to be welded and some special situations, and it has high practicality.

Description

Technical Field

[0001] The invention relates to an ejector pin, in particular to a thread spring ejector pin. Background Art

[0002] When welding the parts to be welded, it is necessary to use spring ejectors to position and press the parts to be welded on the structural parts. The purpose is to solve the problem of poor diffusion of molten solder due to surface tension, and to apply pressure to various parts to be welded. While achieving the purpose of positioning, it also allows the bubbles in the solder to be discharged, thereby reducing the welding void rate of the parts to be welded. However, small springs are prone to fatigue under the influence of high and low temperatures, resulting in the failure of the spring ejector pins to press the parts to be welded. At present, spring ejectors are basically assembled to the cover plate used by interference fit, with poor replaceability and low assembly accuracy. At the same time, spring ejectors assembled by interference fit can only provide a fixed pressure, with poor adjustability, and cannot be flexibly adjusted according to process changes. A new type of spring ejector is urgently needed to solve the above problems. Summary of the invention

[0003] The object of the present invention is to provide a threaded spring ejector pin, which solves the problem that the previous device basically relies on interference fit to be assembled to the cover plate used, has poor replaceability and low assembly accuracy. At the same time, the spring ejector pin assembled by interference fit can only provide a fixed pressure, has poor adjustability, and cannot be flexibly adjusted according to process changes.

[0004] A threaded spring ejector pin comprises a threaded housing, a spring, an ejector pin and a lock buckle.

[0005] The threaded shell is a columnar structure, which includes the nut section, external thread section, and internal thread section from top to bottom; the top of the nut section is provided with an internal hexagonal groove; the external thread section has a threaded cylinder on its outer surface, and a cylindrical coaxial inner hole inside; the internal thread section has a threaded cylindrical cavity inside, and a smooth cylindrical surface on its outer surface; the coaxial inner hole is not connected to the internal hexagonal groove, but is connected to the threaded cylindrical cavity; the thread diameter of the internal thread section is smaller than that of the external thread section. The ejector pin is a columnar structure, which includes the self-centering section, the connecting section, the blocking section, and the ejector pin section from top to bottom; the upper part of the self-centering section is a conical head, and the lower part is a cylinder; the connecting section is a cylinder, and the diameter of the connecting section is smaller than the diameter of the cylinder of the self-centering section; the blocking section is a cylinder; and the ejector pin section is a cylinder with a runway-shaped cross section. The lock buckle is a columnar structure, with external threads and friction rings on the outer surface from top to bottom, and a columnar cavity with a runway-shaped cross section inside; the external threads of the lock buckle are threadedly matched with the threaded cylindrical cavity of the internal thread section. The spring and the ejector pin are both placed in the coaxial inner hole of the threaded shell, one end of the spring contacts the bottom of the coaxial inner hole, and the other end contacts the conical head of the self-centering section. The runway-shaped cross section of the ejector pin section is the same size as the runway-shaped cross section of the columnar cavity of the lock buckle, and a part of the ejector pin section is placed in the columnar cavity of the lock buckle. The outer surface of the cylinder of the self-centering section of the ejector pin contacts the inner surface of the coaxial inner hole of the threaded shell; the outer surface of the ejector pin blocking section contacts the inner surface of the coaxial inner hole of the threaded shell, and the lower surface of the ejector pin blocking section contacts the upper surface of the lock buckle.

[0006] Preferably, the external thread section of the threaded shell is M3, and the internal thread section of the threaded shell is M2.

[0007] Preferably, the total length of the external thread section of the threaded housing is greater than or equal to 10 mm.

[0008] Preferably, the total length of the internal thread section of the threaded housing is greater than or equal to 2.5 mm.

[0009] Preferably, the bottom of the coaxial inner hole of the threaded housing is at least 1.5 mm away from the bottom of the hexagonal groove of the nut segment.

[0010] Preferably, the nut section of the threaded housing is 1.5 mm in length.

[0011] Preferably, the radius of the circumscribed circle of the hexagonal groove of the threaded housing is 1.73 mm, and the depth of the hexagonal groove is 1.5 mm.

[0012] Preferably, the spring is spring steel.

[0013] Preferably, the spring has a spring median diameter d=1.8 mm, an effective number of turns>6, and a free height h=7 mm.

[0014] Preferably, the threaded housing, the spring, the ejector pin and the lock are coaxial.

[0015] The new threaded spring ejector provided by the present invention uses a threaded connection method to replace the traditional interference fit method, and has strong replaceability; and the elastic force of the spring can be adjusted by adjusting the assembly height, and different elastic forces can be used to provide appropriate pressure for different parts to be welded, and it has strong adjustability; it can also play an excellent role in some special situations, such as pressing a warped printed circuit board. The direction in which the ejector and the spring are connected adopts a self-centering structure to ensure the stability of the direction in which the spring provides elastic force; the other end of the ejector is the working surface of the threaded spring ejector, and its shape is a "runway shape", which is convenient for locking and locking the ejector and ensuring that the ejector cannot rotate after assembly. The above-mentioned new threaded spring ejector has a simple structure and is easy to use. It can solve the problem of poor diffusion of molten solder due to surface tension, and can apply pressure to the parts to be welded so as to discharge bubbles in the solder, reducing the void rate of chip welding. The threaded spring ejector has strong adjustability and good replaceability. At the same time, the spring pressure can be adjusted by the external thread to adapt it to different parts to be welded and some special situations, and it has high practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0017] Figure 1 It is a structural schematic diagram of a threaded spring ejector pin;

[0018] Figure 2 It is a cross-sectional view of a threaded spring ejector pin;

[0019] Figure 3 It is a cross-sectional view of the threaded housing;

[0020] Figure 4 is a schematic diagram of the ejector pin;

[0021] Figure 5 A schematic diagram of a lock.

[0022] 1. Threaded housing 2. Spring

[0023] 3. Ejector pin 4. Lock DETAILED DESCRIPTION

[0024] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0025] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0026] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. The meaning of "several" is one or more, unless otherwise clearly and specifically defined.

[0027] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by the terms "up", "down", "front", "back", "left", "right", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0028] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0029] Example 1

[0030] In order to ensure good solder diffusion and low void rate during the welding process, spring ejectors are often used to position and press the parts to be welded. In order to achieve high-quality welding of parts with slight gaps, it is necessary to improve the original spring ejector structure, increase its replaceability and adjustability, and improve welding quality.

[0031] See Figures 1 to 5 The novel thread spring ejector provided by the embodiment of the present invention comprises: a threaded housing 1, a spring 2, an ejector 3 and a lock 4;

[0032] The threaded housing 1 is cylindrical and has a coaxial inner hole, in which a spring 2 and an ejector pin 3 are installed. The threaded housing 1 is fixed to a lock buckle 4 by a threaded connection, and the lock buckle 4 presses the ejector pin 3 and the spring 2 tightly to ensure that the spring 2 always provides a stable pressure to the ejector pin 3.

[0033] When implementing:

[0034] like Figure 2 As shown, the spring 2 and the ejector pin 3 are sequentially placed into the inner hole of the threaded housing 1, and the lock buckle 4 is tightened with the threaded housing 1 to ensure that the spring 2 continuously provides pressure. The pressure is related to the size and material of the spring 2 and the assembly height of the threaded housing 1. In the actual process, the pressure provided by the spring 2 can be achieved by adjusting the assembly height when the size and material of the spring 2 are determined.

[0035] As a feasible implementation method, the threaded shell 1 has a coaxial inner hole, in which the spring 2 and the ejector pin 3 are placed in sequence, and the lock buckle 4 is assembled and fixed to the threaded shell 1 by a threaded connection. At the same time, the lock buckle 4 presses the spring 2 and the ejector pin 3 tightly to ensure that the spring 2 provides stable pressure.

[0036] As an implementable embodiment, the design of the threaded housing 1 can be divided into three sections, namely a nut section, an external thread section, and an internal thread section.

[0037] The nut section of the threaded shell 1 is located at the top of the threaded shell 1, and has a hexagonal groove to facilitate adjustment of the position of the threaded spring ejector pin using a hexagonal wrench. The circumscribed circle radius of the hexagonal groove is designed to be 1.73mm, the depth of the hexagonal groove is designed to be 1.5mm, and the nut section length is 1.5mm.

[0038] The external thread section of the threaded housing 1 is connected to the nut section. The external thread diameter is selected according to the use environment. In this embodiment, M3 is selected. To ensure assembly stability and sufficient telescopic distance of the spring 2 in the inner hole, the total length of the external thread section is not less than 10 mm.

[0039] The internal thread section of the threaded shell 1 is connected to the external thread section to complete the threaded connection with the lock buckle 4. The internal thread diameter must be smaller than the external thread diameter of the external thread section. M2 is selected in this embodiment. The length of the internal thread section needs to ensure the stability of the threaded connection. The length of the internal thread section is not less than 2.5mm.

[0040] As a feasible implementation method, the threaded housing 1 has a coaxial inner hole, the diameter of the coaxial inner hole needs to be slightly smaller than the inner thread diameter, and the bottom of the coaxial inner hole needs to maintain a safety distance of at least 1.5 mm from the bottom of the hexagonal groove in the nut segment.

[0041] The coaxial inner hole is used to place the spring 2 and the ejector pin 3. The coaxial inner hole needs to have a certain depth to meet the expansion and contraction of the spring 2 after assembly. The coaxial inner hole should ensure a small coaxiality to ensure that there is no large deviation in the pressure direction provided by the new threaded spring ejector pin.

[0042] As an implementable embodiment, the ejector pin 3 can be divided into a self-centering section, a connecting section, a blocking section and an ejector pin section in sequence;

[0043] The self-centering section of the ejector pin 3 has a conical head, which relies on the conical head to achieve self-centering of the ejector pin and the spring; the connecting section is cylindrical, and its diameter needs to be slightly smaller than the diameter of the self-centering section; the blocking section is used to abut against the lock to complete the limiting effect; the ejector pin section as a whole is "runway-shaped" to ensure that the ejector pin cannot self-rotate in the inner cavity of the shell, and the plane at the end of the ejector pin section should have a certain flatness to press the surface of the workpiece to be welded.

[0044] As an implementable embodiment, the lock buckle 4 should have a friction ring and an external thread, and the external thread of the lock buckle 4 is connected to the internal thread of the internal thread section of the threaded shell 1; the friction ring is provided to facilitate the disassembly and installation of the new threaded spring ejector when replacing the spring 2 or the ejector 3.

[0045] As an implementable embodiment, the spring 2 should provide sufficient elastic force to ensure the compression of the welded parts while meeting the assembly conditions, but should not be too large to avoid damaging the welded parts.

[0046] In this embodiment, the spring is made of YB(T) / 11 spring steel, the spring center diameter d=1.8mm, the effective number of turns>6, and the free height h=7mm.

[0047] Compared with the prior art, the new threaded spring ejector provided by the present invention has strong adjustability. The assembly height of the threaded spring ejector can be adjusted at any time by relying on the threaded shell, and the pressure provided by the spring at different points can be adjusted to meet different production environments. At the same time, springs of different materials and sizes can be selected to achieve overall and large-scale pressure adjustment. In order to better adapt to springs of different sizes, the side where the ejector and the spring are connected is designed as a self-centering conical structure to ensure that springs of different sizes can provide stable axial pressure. In order to ensure the stability of the spring in a high temperature environment, the material should be high temperature resistant and corrosion resistant spring steel as much as possible. The above-mentioned new threaded spring ejector has a simple structure and is easy to use. It can solve the problem of poor diffusion of molten solder due to surface tension, and can apply pressure to the workpiece to be welded so as to discharge bubbles in the solder, reducing the void rate of chip welding. At the same time, the spring pressure can be adjusted by relying on the external thread to adapt it to different workpieces to be welded and some special situations, and it has high practicality.

[0048] Example 2

[0049] The present invention discloses a novel thread spring ejector pin, which relates to the technical field of welding devices. By applying pressure to various chips and printed circuit boards waiting for welding, the position of the waiting welding parts is fixed, and the diffusion of molten solder during welding heating is improved, bubbles in the solder are discharged, and the welding void rate of the chips and printed circuit boards waiting for welding is reduced. The thread spring 2 ejector pin 3 can adjust the pressure by means of external threads to adapt to the welding of different chips and printed circuit boards in special situations.

[0050] In order to achieve the above object, the present invention provides the following technical solutions:

[0051] The novel thread spring ejector provided by the present invention comprises: a threaded housing 1, a spring 2, an ejector 3, and a lock 4;

[0052] The threaded housing 1 is cylindrical and has a coaxial inner hole, in which a spring 2 and an ejector pin 3 are installed. The threaded housing 1 is fixed to the lock buckle 4 by a threaded connection, and the lock buckle 4 tightly presses the ejector pin 3 and the spring 2 to ensure that the spring 2 always provides a stable pressure to the ejector pin 3. The new threaded spring ejector pin is assembled by the external thread of the threaded housing 1 and the cover plate with a pre-threaded hole.

[0053] A novel thread spring ejector pin comprises: a thread shell 1, a spring 2, an ejector pin 3, and a lock buckle 4;

[0054] The threaded housing 1 is cylindrical and has a coaxial inner hole, into which a spring 2 and an ejector pin 3 are placed in sequence. The threaded housing 1 is fixed to a lock buckle 4 by a threaded connection, and the lock buckle 4 presses the ejector pin 3 and the spring 2 tightly to ensure that the spring 2 always provides pressure to the ejector pin 3.

[0055] The threaded housing 1 can be divided into three sections, the first section is a nut section, the second section is an external thread section, and the third section is an internal thread section.

[0056] The nut section is located at the top of the threaded shell 1 and has an internal hexagonal groove, which is convenient for adjusting the position of the threaded spring 2 ejector pin 3 using an internal hexagonal wrench. The radius of the circumscribed circle of the internal hexagonal groove is 1.73mm, the depth of the internal hexagonal groove is 1.5mm, and the length of the nut section is 1.5mm.

[0057] The external thread section is connected to the nut section, and the external thread diameter is selected according to the use requirements. In order to ensure assembly stability and sufficient telescopic distance of the spring 2 in the inner hole, the total length of the external thread section is not less than 10 mm.

[0058] The internal thread section is used to complete the threaded connection with the lock buckle 4. The internal thread diameter is selected to be smaller than the external thread diameter of the external thread section. The length of the internal thread section needs to ensure the stability of the threaded connection. The length of the internal thread section is not less than 2.5 mm.

[0059] The threaded housing 1 has a coaxial inner hole, the inner hole diameter needs to be slightly smaller than the inner thread diameter, and the bottom of the hole needs to maintain a safety distance of at least 1.5 mm from the bottom of the hexagonal groove in the nut segment.

[0060] The ejector pin 3 can be divided into three sections: a self-centering section, a connecting section, a blocking section and an ejector pin;

[0061] The self-centering section has a conical head, which relies on the conical head to achieve self-centering of the ejector pin 3 and the spring 2; the connecting section is cylindrical, and its diameter needs to be slightly smaller than the diameter of the self-centering section; the blocking section is used to abut against the lock buckle 4 to complete the limiting effect; the working surface of the ejector pin 3 is "runway-shaped" to support the workpiece to be welded.

[0062] The lock buckle 4 should have a friction ring and a thread, and the thread of the lock buckle 4 is connected to the thread of the inner thread section of the threaded shell 1; the friction ring facilitates the replacement of the inner spring 2 of the novel threaded spring ejector pin.

[0063] Under the condition of meeting the assembly requirements, the spring 2 should provide sufficient elastic force to ensure the pressing of the workpiece to be welded, but should not be too large to avoid damaging the workpiece to be welded.

[0064] Example 3

[0065] A threaded spring ejector pin comprises: a threaded housing 1, a spring 2, an ejector pin 3 and a lock buckle 4.

[0066] The threaded shell 1 is a columnar structure, which includes a nut section, an external thread section, and an internal thread section from top to bottom; a hexagonal groove is formed on the top of the nut section; the outer surface of the external thread section is a threaded cylinder, and the interior is a cylindrical coaxial inner hole; the interior of the internal thread section is a threaded cylindrical cavity, and the outer surface is a smooth cylindrical surface; the coaxial inner hole is not connected to the hexagonal groove, and the coaxial inner hole is connected to the threaded cylindrical cavity; the thread diameter of the internal thread section is smaller than the thread diameter of the external thread section.

[0067] The ejector pin 3 is a columnar structure, which includes a self-centering section, a connecting section, a blocking section, and an ejector pin section from top to bottom; the upper part of the self-centering section is a conical head, and the lower part is a cylinder; the connecting section is a cylinder, and the diameter of the connecting section is smaller than the diameter of the cylinder of the self-centering section; the blocking section is a cylinder; and the ejector pin section is a cylinder with a runway-shaped cross section.

[0068] The lock buckle 4 is a columnar structure, with an outer surface having an external thread and a friction ring from top to bottom, and an inner cylindrical cavity with a runway-shaped cross section; the external thread of the lock buckle 4 is threadably matched with the threaded cylindrical cavity of the internal thread section.

[0069] The spring 2 and the ejector pin 3 are both placed in the coaxial inner hole of the threaded housing 1. One end of the spring 2 contacts the upper surface of the coaxial inner hole, i.e. the top, from the bottom of the coaxial inner hole, and the other end contacts the conical head of the self-centering section.

[0070] The racetrack-shaped cross section of the ejector section of the ejector pin 3 is the same as the racetrack-shaped cross section of the columnar cavity of the lock buckle 4 , and a part of the ejector section of the ejector pin 3 is placed in the columnar cavity of the lock buckle 4 .

[0071] The outer surface of the cylinder of the self-centering section of the ejector pin 3 contacts the inner surface of the coaxial inner hole of the threaded housing 1; the outer surface of the blocking section of the ejector pin 3 contacts the inner surface of the coaxial inner hole of the threaded housing 1, and the lower surface of the blocking section of the ejector pin 3 contacts the upper surface of the lock buckle 4.

[0072] The threaded housing 1, the spring 2, the ejector pin 3 and the lock buckle 4 are coaxial.

[0073] A new type of threaded spring ejector relates to the technical field of welding devices. By applying pressure to various chips and printed circuit boards waiting to be welded, while fixing the position of the welded parts, the diffusion of molten solder during the welding heating process is improved, the bubbles in the solder are discharged easily, and the welding void rate of the chips and printed circuit boards waiting to be welded is reduced. The threaded spring 2 and the ejector 3 can adjust the pressure by means of external threads to adapt to the welding of different chips and printed circuit boards in special circumstances. The new type of threaded spring ejector provided by the present invention includes: a threaded shell 1, a spring 2, an ejector 3, and a lock 4; the threaded shell 1 is cylindrical and has a coaxial inner hole, the inner hole is equipped with a spring 2 and an ejector 3, the threaded shell 1 and the lock 4 are fixed by a threaded connection, and the lock 4 presses the ejector 3 and the spring 2 tightly to ensure that the spring 2 always provides a stable pressure to the ejector 3. The new type of threaded spring ejector is assembled by means of the external thread of the threaded shell 1 and a cover plate with a pre-threaded hole. The novel threaded spring ejector pin has a simple structure, is easy to use, has strong adjustability, and is easily replaceable. It can effectively position and press various parts to be welded, reduces the void rate during the welding process, and is highly practical.

Claims

1. A threaded spring ejector pin, characterized in that: include: Threaded housing (1), spring (2), ejector pin (3) and lock (4); The threaded shell (1) is a columnar structure, which comprises a nut section, an external thread section, and an internal thread section from top to bottom; a hexagonal groove is formed on the top of the nut section; the outer surface of the external thread section is a threaded cylinder, and the interior is a cylindrical coaxial inner hole; the interior of the internal thread section is a threaded cylindrical cavity, and the outer surface is a smooth cylindrical surface; the coaxial inner hole is not connected to the internal hexagonal groove, and the coaxial inner hole is connected to the threaded cylindrical cavity; the thread diameter of the internal thread section is smaller than the thread diameter of the external thread section; the ejector pin (3) is a columnar structure, which comprises a self-centering section, a connecting section, a blocking section, and an ejector pin section from top to bottom; the upper part of the self-centering section is a conical head, and the lower part is a cylinder; the connecting section is a cylinder, and the diameter of the connecting section is smaller than the diameter of the cylinder of the self-centering section; the blocking section is a cylinder; the ejector pin section is a cylinder with a runway-shaped cross section; the lock buckle (4) is a columnar structure, and the outer surface is arranged from top to bottom in a conical shape. The outer thread and the friction ring are respectively provided, and the inner part is a cylindrical cavity with a racetrack-shaped cross section; the outer thread of the lock buckle (4) is threadedly matched with the threaded cylindrical cavity of the inner thread section; the spring (2) and the ejector pin (3) are both placed in the coaxial inner hole of the threaded outer shell (1), one end of the spring (2) contacts the bottom of the coaxial inner hole, and the other end contacts the conical head of the self-centering section; the racetrack-shaped cross section of the ejector pin section of the ejector pin (3) is the same as the racetrack-shaped cross section of the cylindrical cavity of the lock buckle (4), and a part of the ejector pin section of the ejector pin (3) is placed in the cylindrical cavity of the lock buckle (4); the outer surface of the cylinder of the self-centering section of the ejector pin (3) contacts the inner surface of the coaxial inner hole of the threaded outer shell (1); the outer surface of the blocking section of the ejector pin (3) contacts the inner surface of the coaxial inner hole of the threaded outer shell (1), and the lower surface of the blocking section of the ejector pin (3) contacts the upper surface of the lock buckle (4); The external thread section of the threaded shell (1) is M3, and the internal thread section of the threaded shell (1) is M2; the total length of the external thread section of the threaded shell (1) is greater than or equal to 10 mm; the total length of the internal thread section of the threaded shell (1) is greater than or equal to 2.5 mm; the bottom of the coaxial inner hole of the threaded shell (1) and the bottom of the hexagonal groove of the nut section maintain a distance of at least 1.5 mm; the length of the nut section of the threaded shell (1) is 1.5 mm; the radius of the circumscribed circle of the hexagonal groove of the threaded shell (1) is 1.73 mm, and the depth of the hexagonal groove is 1.5 mm; the spring (2) is spring steel; the spring median diameter d of the spring (2) is 1.8 mm, the number of effective turns is greater than 6, and the free height h is 7 mm; the threaded shell (1), the spring (2), the ejector pin (3), and the lock buckle (4) are coaxial.

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