A wire quality detection device

Abstract

The present invention relates to the technical field of wire material detection devices, and specifically to a wire material quality detection device, comprising: a detection circuit, including a power supply circuit, a detection instrument connected in series to the power supply circuit, and two detection terminals connected in series to the power supply circuit and kept in position; two wiring terminals, arranged below the two detection terminals and corresponding to the two detection terminals, for fixing the two ends of the wire material; a traction member, including a vertically arranged guide rail, and a counterweight member arranged on the guide rail and movable up and down relative to the guide rail; in a working state, the counterweight member is suspended on the wire material, and the counterweight member pulls the wire material downward under its own weight, and the counterweight member causes the wire material to open an angle between the two wiring terminals. In this solution, by setting a traction mechanism, the problem of deviation in the detection result caused by cross-contact of the wire materials during detection can be avoided.

Description

[Technical field]

[0001] The present invention relates to the technical field of wire material detection devices, and in particular to a wire material quality detection device. [Background technology]

[0002] As an important power transmission device, wires are widely used in all aspects of people's lives. The manufacturing process of wires mainly includes the steps of making the wire core and then sheathing. After the wire core is manufactured, it is usually tested to determine whether the conductive performance of the wire core (i.e., bare wire) is qualified.

[0003] The traditional bare wire detection method mainly relies on manual detection, that is, people hold two test pens to touch the two ends of the bare wire, and then observe the detection instrument to make a judgment. This method is less safe when used, because the bare wire is conductive as a whole before it is sheathed. Therefore, it is easy for people to accidentally touch the bare wire during the detection process, which can easily cause the risk of electric shock. Moreover, because the bare wire is conductive as a whole, once a section of the bare wire crosses and touches, it will affect the entire detection result, so it still needs to be improved. [Summary of the invention]

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a wire quality detection device.

[0005] To solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A wire quality detection device, comprising:

[0007] The detection circuit includes a power supply circuit, a detection instrument connected in series to the power supply circuit, and two detection terminals connected in series to the power supply circuit and kept in position;

[0008] Two wiring terminals are arranged below the two detection terminals and correspond to the two detection terminals for fixing the two ends of the wire;

[0009] The traction component includes a vertically arranged guide rail and a counterweight member arranged on the guide rail and movable up and down relative to the guide rail; in the working state, the counterweight member is suspended on the wire, and the counterweight member pulls the wire downward under its own weight, so that the wire is opened at an angle between the two terminal blocks through the counterweight member.

[0010] The first driving member is used to drive the two connecting terminals to move up and down as a whole. In the initial state, the two connecting terminals and the two detection terminals are spaced apart in the height direction. In the working state, the first driving member drives the two connecting terminals to move upward to contact the two connecting terminals respectively.

[0011] The advantages of adopting this solution are:

[0012] First of all, in this scheme, by setting up a traction mechanism, the problem of wires crossing and contacting each other during detection, which may cause deviations in the detection results, can be avoided. Specifically, during detection, after the two ends of the wire are fixed on the two terminals, the counterweight can be hung on the wire. During the detection process, the first driving member drives the two terminals to rise and finally contact the two detection terminals. During this process, the wire is lifted upward as a whole. During the lifting process, the wire pulls up the counterweight. In this way, the counterweight relies on its own gravity to generate a downward pulling force on the wire, so as to tension the wire and then open an angle between the two terminals. In this way, the wire as a whole will not cross and contact each other.

[0013] Secondly, in this solution, the counterweight is slidably set on the guide rail, so that the guide rail can guide the counterweight. On the one hand, it will not rotate on its own, and on the other hand, it will not swing to the sides. This can prevent the counterweight from swinging or rotating on its own during the process of lifting the counterweight, causing cross-contact of the wires.

[0014] Finally, in this solution, in the initial state, the two wiring terminals and the two detection terminals are spaced apart in the height direction. In the working state, the first driving member drives the two wiring terminals to move upward to contact the two wiring terminals respectively. In this way, in the process of clamping the wires to the wiring terminals, it can be ensured that the entire detection circuit will not conduct the wires, thereby ensuring safety when clamping the wires.

[0015] Preferably, the traction member further comprises a stopper provided on the guide rail and movable up and down relative to the guide rail, and a locking member for locking the position of the stopper; the stopper is located below the counterweight and is used to prevent the counterweight from moving downward.

[0016] Preferably, it further includes a casing, which includes a working station and a clamping station in sequence in the horizontal direction, wherein the front side of the working station is provided with a partition covering the working station, and the front side of the clamping station is open; two detection terminals are provided at the working station; in an initial state, the two detection terminals are at the clamping station; the detection device also includes a second driving member for driving the guide rail and the two wiring terminals to move as a whole between the clamping station and the working station.

[0017] Preferably, a slide rail extending in a horizontal direction is provided in the casing, and a slide seat is slidably provided on the slide rail; the wiring terminals and the guide rail are both provided on the slide seat; and the second driving member is used for driving the slide seat to move.

[0018] Preferably, a truss movable in the height direction is provided on the upper portion of the slide; the two wiring terminals are both provided on the truss; and the first driving member is provided on the slide for driving the truss to move in the height direction.

[0019] Preferably, the detection terminal includes a sleeve and a telescopic part for maintaining positioning; the telescopic part is arranged on the sleeve and can be axially extended and retracted relative to the sleeve, and an elastic part is provided between the telescopic part and the sleeve, so that the telescopic part always maintains a downward pressure tendency through the elastic part; one end of the telescopic part is provided with a first terminal for connecting to the detection circuit, and the other end is provided with a second terminal for abutting against the wiring terminal, and the first terminal and the second terminal are electrically connected.

[0020] Preferably, the telescopic member comprises a shaft body having a cavity inside, a wire is arranged in the cavity, and two ends of the wire are electrically connected to the first terminal and the second terminal respectively.

[0021] Preferably, a first conductive sheet is fixedly connected to the bottom of the cavity; and the second terminal is detachably connected to the bottom of the shaft and is in contact with the first conductive sheet.

[0022] Preferably, the first terminal comprises a second conductive sheet connected to the conducting wire and a wiring component for wiring the detection circuit, and the wiring of the detection circuit is brought into contact with the second conductive sheet through the wiring component.

[0023] Preferably, the elastic member is a spring; the upper end of the sleeve is an open end, and the open end is detachably connected to a cover, and the middle of the cover has a through hole for axial movement of the shaft body; the shaft body is located in the sleeve and has a stopper on the shaft wall; the spring is sleeved on the shaft body, and its two ends are respectively in contact with the cover and the stopper.

Brief Description of the Drawings

[0024] The present invention will be further described below in conjunction with the accompanying drawings:

[0025] Figure 1 It is a structural schematic diagram of the present invention;

[0026] Figure 2 It is a schematic diagram of the structure of the present invention (without the partition);

[0027] Figure 3 It is a structural schematic diagram of the slide seat part;

[0028] Figure 4 It is a schematic diagram of the structure of the back side of the slide;

[0029] Figure 5 for Figure 3 Enlarged view of part A in the middle;

[0030] Figure 6 It is a structural schematic diagram of the truss;

[0031] Figure 7 It is a structural schematic diagram of the detection terminal;

[0032] Figure 8 Schematic diagram of the internal structure of the detection terminal. [Specific implementation method]

[0033] The technical solutions of the embodiments of the present invention are explained and described below in conjunction with the drawings of the embodiments of the present invention, but the following embodiments are only preferred embodiments of the present invention, not all. Based on the embodiments in the implementation mode, other embodiments obtained by those skilled in the art without creative work are all within the protection scope of the present invention.

[0034] In the following description, terms such as "inside", "outside", "up", "down", "left", "right", etc. that indicate directions or positional relationships are only used to facilitate the description of the embodiments and simplify the description, and do not indicate or imply that the referred device or element must have a specific direction, be constructed and operate in a specific direction. Therefore, they should not be understood as limitations on the present invention.

[0035] Example:

[0036] like Figures 1 to 8 As shown, the display is a wire quality detection device, which is mainly used for the detection of wire cores. The wire core here refers to the bare wire without sheathing. The wire shown in the M part of the figure includes:

[0037] like Figure 1 As shown, the detection circuit (not shown in the figure) includes a power supply circuit, a detection instrument connected in series to the power supply circuit, and two detection terminals 2 connected in series to the power supply circuit and kept in position; it is worth noting that the detection instrument here can be an ammeter, a voltmeter, etc.; the power supply circuit mainly provides electric energy during detection, and an open circuit is set between the two detection terminals 2, that is, when the two detection terminals 2 are not connected, the entire power supply circuit is in an open circuit state.

[0038] Combination Figure 3 and Figure 6 As shown, two wiring terminals 3 are arranged below the two detection terminals 2 and correspond to the two detection terminals 2 for fixing the two ends of the wire; the wiring terminal 3 specifically includes an L-shaped conductive block 31, a first screw 32 is provided on the front side of the conductive block 31, and a first nut 33 is provided on the first screw 32. When wiring, the end of the wire is wound around the first screw 32, and then the first nut 33 is tightened, and the wire is pressed against the conductive block 31 through the first nut 33, so that the wire is electrically connected to the conductive block 31, and the upper part of the conductive block 31 is mainly used to contact with the detection terminal 2 to achieve electrical connection.

[0039] Combination Figure 1 , 3As shown in Figures 5 and 6, the traction member 4 includes a vertically arranged guide rail 41, and a counterweight 42 arranged on the guide rail 41 and movable up and down relative to the guide rail 41; in the working state (i.e., during detection), the counterweight 42 is suspended on the wire, and the counterweight 42 pulls the wire downward under its own weight, so that the wire is opened at an angle between the two connecting terminals 3 through the counterweight 42. Specifically, a through hole 421 is provided on the counterweight 42 for the wire to pass through. When clamping the wire, the wire is first passed through the through hole 421, and then the two ends of the wire are clamped to the two connecting terminals 3 respectively.

[0040] like Figure 4 As shown, the first driving member 51 is used to drive the two connecting terminals 3 to move up and down as a whole. In the initial state, the two connecting terminals 3 and the two detection terminals 2 are spaced apart in the height direction, so as to avoid direct contact between the connecting terminals 3 and the detection terminals 2 when clamping the wires, resulting in the detection circuit being turned on and causing the risk of electric shock. In the working state, the first driving member 51 drives the two connecting terminals 3 to move upward to contact the two connecting terminals 3 respectively. After the two are in contact, the whole detection circuit is turned on, and the detection result can be obtained by observing the detection instrument.

[0041] By setting up a traction mechanism, the problem of wires crossing and contacting each other during detection, which may lead to deviation in the detection results, can be avoided. Specifically, during detection, such as Figure 3 As shown, after the two ends of the wire are fixed on the two connecting terminals 3, the counterweight 42 can be hung on the wire. During the detection process, the first driving member 51 drives the two connecting terminals 3 to rise and finally contact the two detection terminals 2. In this process, the wire is lifted upward as a whole. During the lifting process, the wire pulls up the counterweight 42. In this way, the counterweight 42 relies on its own gravity to generate a downward pulling force on the wire, so that the wire is tensioned, and then an angle is opened between the two connecting terminals 3, so that the wire as a whole will not cross and contact.

[0042] Secondly, in this solution, the counterweight 42 is slidably set on the guide rail 41, so that the guide rail 41 can guide the counterweight 42. On the one hand, the counterweight 42 will not rotate on its own, and on the other hand, the counterweight 42 will not swing to the sides. This can prevent the counterweight 42 from swinging or rotating itself during the process of lifting the counterweight 42, causing cross-contact of the wires.

[0043] Finally, in this solution, in the initial state, the two connecting terminals 3 and the two detection terminals 2 are spaced apart in the height direction. In the working state, the first driving member 51 drives the two connecting terminals 3 to move upward to contact the two connecting terminals 3 respectively, so that in the process of clamping the wires to the connecting terminals 3, it can be ensured that the entire detection circuit will not conduct the wires, thereby ensuring safety when clamping the wires.

[0044] Since the counterweight 42 is free to slide on the guide rail 41, if the counterweight 42 is not restricted, the counterweight 42 will fall to the bottom of the guide rail 41 under its own weight. Each time the wires are threaded (especially for the same batch of wires of equal length), the counterweight 42 needs to be manually moved up to slide to a suitable height. Moreover, when clamping the wires, the counterweight 42 needs to be supported by hand to prevent it from falling directly. If the counterweight 42 is not supported, when the wires are clamped on the terminal 3, the counterweight 42 will pull down the wires, causing the wires to have downward tension. As a result, when the wires are clamped on the terminal 3, people need to overcome the tension of the wires to clamp them, which is inconvenient to operate. Therefore, this embodiment is further improved:

[0045] like Figure 5 As shown, the traction member 4 also includes a stopper 43 disposed on the guide rail 41 and movable up and down relative to the guide rail 41, and a locking member 44 for locking the position of the stopper 43, wherein the locking member 44 may be a bolt, which is threadedly connected to the stopper 43, and when locked, the inner end of the bolt contacts the guide rail 41 to prevent the stopper 43 from sliding. The stopper 43 is located below the counterweight 42 and is used to prevent the counterweight 42 from moving downward.

[0046] When inspecting wires of the same batch and of equal length, the counterweight 42 is first initially positioned. The specific steps are as follows: fix one end of the wire on one of the terminals 3, then slide the counterweight 42 up to a certain height, and then pass the other end of the wire through the counterweight 42 to be pulled to the other terminal 3 and clamped with the terminal 3, then slide the stopper 43 up to the bottom of the counterweight 42, and then continue to slide the stopper 43 up a short distance (the purpose of this operation is to provide a wire clamping margin, so that when the next wire is clamped at this height, the wire is in a relaxed state during the clamping process and is not tensioned), at which time the counterweight 42 also moves up a distance accordingly, and then locks the position of the stopper 43 to complete the initial positioning of the counterweight 42.

[0047] When the wire of the same length is tested subsequently, there is no need to adjust the position of the stopper 43. When clamping, it is only necessary to pass the wire through the counterweight 42, and then clamp the two ends of the wire to the two terminal blocks 3 respectively. Since the initial height of the counterweight 42 has been determined at this time, the counterweight 42 will not fall under the support of the stopper 43, and at this height, the wire is basically in a relaxed state during the clamping process, so the counterweight 42 does not need to be continuously pulled up. In this way, there is basically no need to overcome the tension of the wire to clamp the wire to the terminal blocks 3, which facilitates the clamping operation.

[0048] Furthermore, since the stopper 43 can slide up and down along the guide rail 41, the initial height of the stopper 43 can be adjusted according to the different lengths of the wires. For example, if a batch of wires is shorter, the initial height of the stopper 43 can be adjusted higher accordingly. On the contrary, if the wires are longer, the initial height of the stopper 43 can be adjusted lower accordingly.

[0049] In order to further avoid the risk of electric shock caused by people touching the wires during the test, Figure 1 and Figure 2 As shown, the present embodiment also includes a housing 1, which includes a working station 12 and a clamping station 11 in the horizontal direction, wherein the working station 12 is the actual detection area, and the clamping station 11 is the area for clamping the wire before detection. In other words, the work of clamping the wire is performed at the clamping station 11, and the detection work is performed at the working station 12.

[0050] The front side of the work station 12 is provided with a partition 13 covering the work station 12, and the partition 13 is used to shield the front side of the work station 12. Under the blocking of the partition 13, it can prevent the hands from touching the wires during the inspection, causing the risk of electric shock. Of course, in order to observe the inspection process intuitively, the partition 13 can be made of transparent material.

[0051] The front side of the clamping station 11 is open, and people perform clamping operations from the open area;

[0052] The two detection terminals 2 are arranged at the working station 12, so that the detection process must be carried out at the working station 12; in the initial state, the two detection terminals 2 are at the clamping station 11; Figure 2 and Figure 3 As shown, the detection device also includes a second driving member 16 for driving the guide rail 41 and the two wiring terminals 3 to move as a whole between the clamping station 11 and the working station 12. When clamping the wire, the two wiring terminals 3 and the guide rail 41 are pulled to the clamping station 11 by the second driving member 16. At this time, the wiring terminals 3 and the detection terminals 2 are staggered and cannot be connected. At this time, the wire can be clamped safely. After the clamping is completed, the two wiring terminals 3 are driven to the working station 12 (the two wiring terminals 3 are directly below the two detection terminals 2) by the second driving member 16, and the two wiring terminals 3 are driven to rise by the first driving member 51 to contact and conduct with the detection terminals 2 for detection.

[0053] like Figure 2 As shown, a slide rail 15 extending in a horizontal direction is provided in the housing 1, and a slide seat 14 is slidably provided on the slide rail 15; the wiring terminal 3 and the guide rail 41 are both provided on the slide seat 14; and the second driving member 16 is used for driving the slide seat 14 to move.

[0054] like Figure 3As shown, a truss 52 movable in the height direction is provided on the upper portion of the slide 14; the truss 52 is horizontally arranged, and the two wiring terminals 3 are arranged on the truss 52; the first driving member 51 is arranged on the slide 14 for driving the truss 52 to move in the height direction, and the first driving member 51 and the second driving member 16 can be a cylinder, a hydraulic cylinder, or a screw module.

[0055] In order to ensure that the detection terminal 2 and the connection terminal 3 can contact more firmly during the detection process, Figure 7 and Figure 8 As shown, the detection terminal 2 includes a sleeve 21 and a telescopic member for maintaining positioning; specifically, the sleeve 21 is vertically fixedly installed on the upper wall of the work station 12, and the telescopic member is arranged on the sleeve 21 and can be axially telescopic relative to the sleeve 21. An elastic member is arranged between the telescopic member and the sleeve 21, and the telescopic member is always kept in a downward pressure trend by the elastic member; one end of the telescopic member is provided with a first terminal 25 for connecting to the detection circuit, and the other end is provided with a second terminal 24 for the connection terminal 3 to abut, and the first terminal 25 and the second terminal 24 are electrically connected. During the detection, the first driving member 51 lifts the truss 52, so that the two connection terminals 3 gradually approach the two second terminals 24, and then the connection terminals 3 continue to move upward, and the connection terminals 3 will overcome the elastic force of the elastic member and push the telescopic member upward, so that under the elastic force of the elastic member, the telescopic member will press the second terminal 24 against the connection terminal 3, so that the two can be in close contact.

[0056] Specifically: the telescopic member includes a shaft body 22 with a cavity inside, wherein the shaft body 22 is made of insulating material, and a wire 27 is provided in the cavity, and the two ends of the wire 27 are electrically connected to the first terminal 25 and the second terminal 24 respectively. In this embodiment, the wire 27 is placed in the shaft body 22, so that the wire 27 can be protected by the shaft body 22, and because the shaft body 22 is insulated, a person will not get an electric shock when touching the shaft body 22.

[0057] In order to facilitate the replacement of the second terminal 24, in this embodiment, the bottom of the cavity is fixedly connected with a first conductive sheet 26; the second terminal 24 is detachably connected to the bottom of the shaft 22 and contacts the first conductive sheet 26, for example Figure 8 As shown, a screw hole is provided on the bottom wall of the shaft body 22 , and an integrally formed threaded portion is provided on the second terminal 24 . The second terminal 24 is screwed into the screw hole through the threaded portion to abut against the first conductive sheet 26 .

[0058] The first terminal includes a second conductive sheet 251 connected to the wire 27 and a wiring component for wiring the detection circuit. The wiring component is used to make the circuit of the detection circuit contact the second conductive sheet 251. Specifically, the wiring component includes a second screw 252 vertically fixed on the top of the shaft 22 and a second nut 253 provided on the second screw 252. When the detection circuit is wired, its circuit is wound around the second screw 252, and then the second nut 253 is tightened to press the circuit onto the second conductive sheet 251.

[0059] Of course, in order to avoid exposure of the second conductive sheet 251, in this embodiment, the wiring component also includes an insulating cover 255 with a bottom opening and a third nut 254 adapted to the second screw 252. A clearance opening 2551 is provided on the bottom side wall of the cover 255 for the detection circuit to pass through; a hole is opened on the top of the cover 255 for the second screw 252 to pass through. During installation, the detection circuit and the second conductive sheet 251 are first clamped, and then the cover 255 is covered on the top of the shaft 22. During this process, the detection circuit passes through the clearance opening 2551, and then the third nut 254 is screwed onto the second screw 252 until the third nut 254 is pressed against the top wall of the cover 255.

[0060] By providing the cover body 255, the connection area between the detection circuit and the conductive sheet can be shielded, thereby improving safety.

[0061] In order to facilitate the replacement of the elastic part, in this embodiment, the elastic part is a spring 23; the upper end of the sleeve 21 is an open end, and the open end is detachably connected with a cover 211, for example, the cover 211 is threadedly connected to the shaft body 22, specifically, an internal thread is provided on the inner wall of the cover 211, and an external thread is provided on the outer wall of the shaft body 22, and the internal thread and the external thread cooperate to achieve a threaded connection, and a through hole is provided in the middle of the cover 211 for axial movement of the shaft body 22; the shaft body 22 is provided with a stopper on the shaft wall located in the sleeve 21; the spring 23 is sleeved on the shaft body 22, and its two ends are respectively in conflict with the cover 211 and the stopper, so that when replacing the elastic part, the cover 211 can be unscrewed, and then the spring 23 can be pulled out upward.

[0062] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes but is not limited to the contents described in the drawings and the above specific embodiments. Any modification that does not deviate from the functional and structural principles of the present invention will be included in the scope of the claims.

Claims

1. A wire quality detection device, characterized in that: Used for wire core detection, including: The detection circuit includes a power supply circuit, a detection instrument connected in series to the power supply circuit, and two detection terminals connected in series to the power supply circuit and kept in position; Two wiring terminals are arranged below the two detection terminals and correspond to the two detection terminals for fixing the two ends of the wire; The traction member includes a vertically arranged guide rail and a counterweight member arranged on the guide rail and movable up and down relative to the guide rail; in a working state, the counterweight member is suspended on the wire, and the counterweight member pulls the wire downward under its own weight, so that the wire opens at an angle between the two wiring terminals through the counterweight member; A first driving member is used to drive the two connecting terminals to move up and down as a whole. In an initial state, the two connecting terminals and the two detection terminals are arranged at intervals in the height direction. In a working state, the first driving member drives the two connecting terminals to move upward to contact the two connecting terminals respectively. It also includes a casing, which includes a working station and a clamping station in sequence in the horizontal direction, wherein the front side of the working station is provided with a partition covering the working station, and the front side of the clamping station is open; two detection terminals are arranged at the working station; in an initial state, the two detection terminals are at the clamping station; the detection device also includes a second driving member for driving the guide rail and the two wiring terminals to move as a whole between the clamping station and the working station.

2. A wire quality detection device according to claim 1, characterized in that: The traction member also includes a stopper disposed on the guide rail and movable up and down relative to the guide rail, and a locking member for locking the position of the stopper; the stopper is located below the counterweight and is used to prevent the counterweight from moving downward.

3. A wire quality detection device according to claim 1, characterized in that: A slide rail extending in the horizontal direction is arranged in the housing, and a slide seat is slidably arranged on the slide rail; the wiring terminals and the guide rail are both arranged on the slide seat; and the second driving member is used for driving the slide seat to move.

4. A wire quality detection device according to claim 3, characterized in that: A truss movable in the height direction is arranged on the upper part of the slide; the two wiring terminals are arranged on the truss; the first driving member is arranged on the slide to drive the truss to move in the height direction.

5. A wire quality detection device according to claim 1, characterized in that: The detection terminal includes a sleeve and a telescopic part for maintaining positioning; the telescopic part is arranged on the sleeve and can be axially extended and retracted relative to the sleeve, and an elastic part is arranged between the telescopic part and the sleeve, so that the telescopic part always maintains a downward pressure trend through the elastic part; one end of the telescopic part is provided with a first terminal for connecting to the detection circuit, and the other end is provided with a second terminal for abutting against the wiring terminal, and the first terminal and the second terminal are electrically connected.

6. A wire quality detection device according to claim 5, characterized in that: The telescopic member comprises a shaft body with a cavity inside, a wire is arranged in the cavity, and two ends of the wire are electrically connected to a first terminal and a second terminal respectively.

7. A wire quality detection device according to claim 6, characterized in that: The bottom of the cavity is fixedly connected with a first conductive sheet; the second terminal is detachably connected to the bottom of the shaft body and is in contact with the first conductive sheet.

8. A wire quality detection device according to claim 6, characterized in that: The first terminal includes a second conductive sheet connected to the wire and a wiring component for connecting the detection circuit, and the wiring component allows the line of the detection circuit to contact the second conductive sheet.

9. A wire quality detection device according to claim 5, characterized in that: The elastic member is a spring; the upper end of the sleeve is an open end, and the open end is detachably connected to a cover, and the middle of the cover has a through hole for axial movement of the shaft body; the shaft body is located in the sleeve and has a stopper on the shaft wall; the spring is sleeved on the shaft body, and its two ends are respectively in contact with the cover and the stopper.

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