CN212625314U - Bottom plate structure, key assembly and electronic device - Google Patents

Abstract

The utility model discloses a bottom plate structure, button subassembly and electron device, bottom plate structure includes bottom plate, mounting and connecting piece, and the bottom plate has first surface, second surface, first perforation and at least one second perforation, and the first surface is relative with the second surface, and first perforation and at least one second perforation run through first surface and second surface, and at least one second perforation is located around first perforation; the fixing piece is positioned on the bottom plate, one part of the fixing piece is arranged in the first through hole, and the other part of the fixing piece extends towards the direction far away from the bottom plate; the connecting piece passes through the at least one second perforation and is configured on the bottom plate, the connecting piece covers part of the first surface and the second surface, and covers part of the side surface of the fixing piece. The utility model discloses a bottom plate structure realizes the lightweight, lets use the utility model discloses a light-weighted can also be realized to bottom plate structure's button subassembly and electron device, can be connected through the mounting firmly between bottom plate structure and the electron device simultaneously.

Description

Bottom plate structure, key assembly and electronic device

Technical Field

The utility model relates to an input device's technical field especially relates to a bottom plate structure, button subassembly and electron device.

Background

The key structure used in the electronic device at present includes a bottom plate, a circuit board, an elastic member, a key cap, and a lifting mechanism, wherein the bottom plate usually uses a metal bottom plate (such as an iron plate), and the metal bottom plate needs to have a certain thickness, so that the metal bottom plate maintains a certain rigidity to support the circuit board, the elastic member, the key cap, the lifting mechanism, and other elements, and can be stably connected to a housing of the electronic device. The metal bottom plate leads to the bottom plate to have certain weight because of having certain thickness, leads to the button structure to have certain weight. However, the electronic device is developed toward light weight, but the electronic device cannot be light-weighted due to the key structure.

SUMMERY OF THE UTILITY MODEL

The embodiment of the utility model provides a bottom plate structure, button subassembly and electron device solves present button structure and uses heavier metal soleplate, leads to the unable lightweight of button structure, and then lets the electron device who uses the button structure also unable lightweight problem.

In order to solve the technical problem, the utility model discloses a realize like this:

in one embodiment, there is provided a floor structure comprising: a base plate having a first surface, a second surface, a first perforation and at least one second perforation, the first surface being opposite the second surface, the first perforation and the at least one second perforation extending through the first surface and the second surface, the at least one second perforation being located around the first perforation; the fixing piece is positioned on the bottom plate, one part of the fixing piece is arranged in the first through hole, and the other part of the fixing piece extends towards the direction far away from the bottom plate; and the connecting piece passes through the at least one second through hole and is arranged on the bottom plate, covers part of the first surface and the second surface and covers part of the side surface of the fixing piece.

In another embodiment, a key assembly is provided that includes: the floor structure as described in the above embodiments; the thin film circuit board is arranged on the bottom plate structure; the elastic piece is arranged on the thin film circuit board; the keycap is arranged on the elastic piece; and the lifting mechanism is arranged between the bottom plate structure and the keycap.

In yet another embodiment, an electronic device is provided, comprising: a housing having a through hole; the key assembly in the above embodiment is disposed on the casing, and the fixing member corresponds to the through hole; and a housing fixing member passing through the through hole and engaged with the fixing hole of the fixing member.

The embodiment of the utility model provides an in, through the bottom plate that changes present button structure, through the bottom plate structure that forms through using bottom plate, mounting and connecting piece combination promptly, so can let the bottom plate in the bottom plate structure use slice, and the material of bottom plate is not limited to metal or nonmetal, not only can alleviate the holistic weight of bottom plate structure, has good connectivity simultaneously, lets the button subassembly that uses the bottom plate structure realize the lightweight, and then lets the electronic device who uses the button subassembly realize the lightweight.

Drawings

The accompanying drawings, which are described herein, serve to provide a further understanding of the invention and constitute a part of this specification, and the exemplary embodiments and descriptions thereof are provided for explaining the invention without unduly limiting it. In the drawings:

fig. 1 is a cross-sectional view of a key assembly according to a first embodiment of the present invention:

fig. 2 is a perspective view of a floor structure according to a first embodiment of the present invention;

fig. 3 is an exploded view of the floor structure of the first embodiment of the present invention;

FIG. 4 is a cross-sectional view taken along line A-A' of FIG. 2;

fig. 5 is a sectional view of a floor structure of a second embodiment of the present invention;

fig. 6 is an exploded view of a floor structure according to a third embodiment of the present invention;

fig. 7 is an exploded view of a floor structure according to a fourth embodiment of the present invention;

fig. 8 is a sectional view of a floor structure of a fifth embodiment of the present invention;

fig. 9 is a sectional view of a floor structure according to a sixth embodiment of the present invention; and

fig. 10 is a sectional view of an electronic device according to a seventh embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, of the embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

Please refer to fig. 1, which is a cross-sectional view of a key assembly according to a first embodiment of the present invention; as shown in the figures, the key assembly 1 of the present embodiment includes a bottom plate structure 10, a thin film circuit board 11, an elastic component 12, a key cap 13 and a lifting mechanism 14, wherein the thin film circuit board 11 is disposed on the bottom plate structure 10, the elastic component 12 is disposed on the thin film circuit board 11, the key cap 13 is disposed on the elastic component 12, the lifting mechanism 14 is disposed between the bottom plate structure 10 and the key cap 13, one end of the lifting mechanism 14 is connected to the bottom plate structure 10, and the other end of the lifting mechanism 14 is connected to the key cap 13. In an embodiment, the key assembly 1 of the present embodiment further includes a backlight module (not shown), and the backlight module is disposed on a surface of the bottom plate structure 10 away from the thin film circuit board 11. Fig. 1 shows only a part of key assembly 1 for convenience of explanation.

Please refer to fig. 2, fig. 3 and fig. 4, which are a perspective view, an exploded view and a cross-sectional view along a line a-a' in fig. 2 of a bottom plate structure according to a first embodiment of the present invention; as shown, the same figures 2, 3 and 4 also show the main parts of the floor structure 10, for the sake of the following description of the floor structure 10. The base plate structure 10 of the present embodiment includes a base plate 101, a fixing member 102 and a connecting member 103, wherein the base plate 101 has a first surface 101a, a second surface 101b, a first through hole 1011 and at least one second through hole 1012, the first surface 101a and the second surface 101b are opposite, the first surface 101a is an upper surface of the base plate 101, and the second surface 101b is a lower surface of the base plate 101. The first and second through holes 1011 and 1012 penetrate the first and second surfaces 101a and 101b, and the at least one second through hole 1012 is disposed around the first through hole 1011 and spaced apart from the first through hole 1011. Specifically, the number of the first through holes 1011 of the present embodiment is one, the number of the second through holes 1012 is four, and four second through holes 1012 are provided around the first through holes 1011; preferably, four second through holes 1012 may be symmetrically spaced.

The fixing member 102 can be positioned in the first through hole 1011, in this embodiment, a portion of the fixing member 102 is disposed in the first through hole 1011, and another portion of the fixing member 102 extends away from the bottom plate 101. Specifically, the fixing member 102 has a fixing body 1021 and a fixing flange 1022, the fixing body 1021 of the present embodiment has a fixing hole 10211, and the fixing hole 10211 is formed with a passage that longitudinally penetrates or does not penetrate the fixing body 1021; the fixing flange 1022 is disposed around a side surface of the fixing body 1021 and extends along the horizontal direction of the bottom plate 101, wherein the fixing flange 1022 may be a continuous or discontinuous plate-shaped structure disposed around the side surface of the fixing body 1021. The fixing flange 1022 divides the fixing body 1021 into a first fixing end portion 1021a and a second fixing end portion 1021b, that is, the first fixing end portion 1021a and the second fixing end portion 1021b are located at both sides of the fixing flange 1022, respectively. In this embodiment, the fixing member 102 may be a stud or a nut, and the fixing body 1021 of the fixing member 102 has a hollow cavity and a fixing hole 10211 with an internal thread, i.e. an internal thread is formed on an inner wall of a passage of the fixing hole 10211. When the fixing element 102 is disposed in the first through hole 1011, the second fixing end 1021b is located in the first through hole 1011, the upper surface of the fixing flange 1022 abuts against the second surface 101b of the base plate 101 and is located between the first through hole 1011 and the second through hole 1012, and the fixing flange 1022 does not shield the four second through holes 1012. The first fixing end 1021a is located on the second surface 101b of the base plate 101 and extends away from the second surface 101b, that is, the first fixing end 1021a protrudes from the second surface 101b of the base plate 101 and extends substantially perpendicular to the base plate 101, and in the figure, the first fixing end 1021a is located below the second surface 101b of the base plate 101. When the second surface 101b of the bottom plate 101 is directed upward in the drawing, the first fixed end 1021a is located above the second surface 101b of the bottom plate 101. In another embodiment, the first fixing end 1021a can also protrude from the first surface 101a of the base plate 101, but not limited thereto.

The connecting member 103 is disposed on the base plate 101, and the connecting member 103 passes through the plurality of second through holes 1012 and covers a portion of the first surface 101a and the second surface 101b of the base plate 101 while covering a portion of the side surface of the fixing member 102 to fix the fixing member 102 to the base plate 101. Specifically, the connection member 103 has a first connection end 1031, a second connection end 1032, and a plurality of connection portions 1033 corresponding to the second through holes 1012, respectively. Wherein the first connection end 1031 is opposite to the second connection end 1032, and the connection portion 1033 connects the first connection end 1031 and the second connection end 1032. The first connecting end 1031 is overlaid on the first surface 101a of the base plate 101, the second connecting end 1032 is overlaid on the second surface 101b of the base plate 101 and the fixing flange 1022 of the fixing member 102, and the fixing flange 1022 is located between the second connecting end 1032 of the connecting member 103 and the second surface 101b of the base plate 101. The second connection end 1032 is located below the second surface 101b of the base plate 101 and the fixing flange 1022 of the fixing member 102 in the drawing, and the second connection end 1032 covers a side surface of the first fixing end 1021a of the fixing member 102. A plurality of connecting portions 1033 are respectively located in the corresponding second through holes 1012, and each connecting portion 1033 is connected to the first connecting end 1031 and the second connecting end 1032 and covers the fixing flange 1022, so that the fixing member 102 can be fixed to the base plate 101 by covering the fixing flange 1022 with the connecting member 103.

In the embodiment, a portion of the fixing member 102 is engaged with the first through hole 1011, for example, the second fixing end 1021b is engaged with the first through hole 1011, so that the fixing member 102 is connected to the bottom plate 101 in advance. Next, the connecting member 103 is formed on the bottom plate 101 by injection molding and covers a portion of the bottom plate 101 and the fixing member 102. The connecting member 103 is a plastic fluid before being molded, and can pass through the plurality of second through holes 1012, partially cover the first surface 101a of the bottom plate 101, partially cover the second surface 101b of the bottom plate 101 and the fixing flange 1022 located under the second surface 101b, and cover a part of the side surface of the first fixing end 1021a located under the second surface 101 b. After the connecting member 103, which is a plastic fluid, is molded, the connecting member 103 is molded on the base plate 101 and the fixing member 102, and finally, the connecting member 103 increases the engaging force to stably fix the fixing member 102 to the base plate 101.

In addition, the fixing flange 1022 of the fixing member 102 abuts against the second surface 101b of the base plate 101 and is covered by the connecting member 103, increasing the contact area between the fixing member 102 and the base plate 101 and the contact area between the fixing member 102 and the connecting member 103, thereby increasing the structural strength between the base plate 101, the fixing member 102, and the connecting member 103. Of course, the fixing member 102 of the present embodiment can also omit the fixing flange 1022, and is not limited thereto.

The bottom plate 101 of the bottom plate structure 10 of the present embodiment is sheet-like, and the weight of the bottom plate structure 10 can be effectively reduced, and the weight of the key assembly 1 can be reduced, so that the weight of the bottom plate structure 10 and the weight of the key assembly 1 can be reduced. Since the bottom plate 101 is thin and thin, it can be firmly connected to the housing of the electronic device by the fixing member 102. The material of the bottom plate 101 of this embodiment may be metal, metal alloy or nonmetal, such as carbon fiber or plastic; the fixing member 102 may be made of metal or plastic, wherein the metal is, for example, a metal stud or a copper nut, but not limited thereto; the connecting member 103 is made of plastic, so that the weight of the bottom plate structure 10 can be effectively reduced, and the effect of light weight can be achieved.

Please refer to fig. 5, which is a cross-sectional view of a bottom plate structure according to a second embodiment of the present invention; as shown in the drawings, the bottom plate structure 10 of the present embodiment is different from the bottom plate structure of the first embodiment in that the fixing body 1021 of the fixing member 102 of the present embodiment omits the second fixing end, and the fixing flange 1022 is located at an end face of the fixing body 1021. When the fixing member 102 is disposed on the base plate 101, the fixing flange 1022 of the fixing member 102 can abut against the first surface 101a or the second surface 101b of the base plate 101, and in this embodiment, the fixing flange 1022 is located on the first surface 101a of the base plate 101 and located between the first connecting end 1031 of the connecting member 103 and the first surface 101a of the base plate 101. The fixing body 1021 of the fixing member 102 passes through the first through hole 1011, the fixing body 1021 protrudes from the second surface 101b of the bottom plate 101, that is, the fixing flange 1022 abuts against the first surface 101a of the bottom plate 101, and the fixing body 1021 is located below the first surface 101a of the bottom plate 101. The function of the fixing flange 1022 of this embodiment is the same as that of the fixing flange of the first embodiment, and will not be described herein.

Please refer to fig. 6, which is an exploded view of a bottom plate structure according to a third embodiment of the present invention; as shown in the drawings, the bottom plate structure 10 of the present embodiment is different from the bottom plate structure of the above embodiments in that the number of the second through holes 1012 of the bottom plate 101 of the present embodiment is one, so the number of the connection portions 1033 of the connection member 103 is also relatively one, and the number of the connection portions 1033 matches the number of the second through holes 1012. The second through hole 1012 may be a circular hole, an arc hole, an elongated hole or a slot of any shape, the second through hole 1012 of the embodiment is a C-shaped slot, and a space is provided between two ends of the second through hole 1012, so that the bottom plate 101 between the first through hole 1011 and the second through hole 1012 can be connected to the bottom plate 101 outside the second through hole 1012, and thus the volume of the connecting portion 1033 of the connecting member 103 located in the second through hole 1012 can be increased, and the connecting strength between the connecting portion 1033 and the first connecting end 1031 and the second connecting end 1032 can be increased, and further the connecting member 103 can firmly fix the fixing member 102 on the bottom plate 101. The fixing member 102 and the connecting member 103 are arranged in the same manner as in the above-described embodiment, and are not described again. The present embodiment illustrates that the minimum number of the second through holes 1012 is one, but the number of the second through holes 1012 may be two, three, four or more.

Please refer to fig. 7, which is an exploded view of a bottom plate structure according to a fourth embodiment of the present invention; as shown in the drawings, the bottom plate structure 10 of the present embodiment is different from the bottom plate structure of the previous embodiments in that the number of the fixing flanges 1022 of the fixing member 102 of the present embodiment is two, and the two fixing flanges 1022 are disposed on the side surface of the fixing body 1021 at intervals, i.e., the fixing flanges 1022 of the present embodiment are of a non-continuous floor-like structure. The fixing member 102 is provided on the base plate 101 in the same manner as the fixing member of the above-described embodiment is provided on the base plate. The two fixing flanges 1022 of this embodiment have the same functions as those of the fixing flanges of the previous embodiments, and are not described herein again. Of course, the number of the fixing flanges 1022 may be three or more.

Please refer to fig. 8, which is a cross-sectional view of a bottom plate structure according to a fifth embodiment of the present invention; as shown in the drawings, the bottom plate structure 10 of the present embodiment is different from the bottom plate structure of the first embodiment in that the side surface of the first fixing end 1021a of the fixing body 1021 of the fixing element 102 of the present embodiment has a microstructure 1023, the microstructure 1023 of the present embodiment is located on the side surface of the first fixing end 1021a, which is in contact with the connecting element 103, and the connecting element 103 can penetrate into the microstructure 1023 during molding, so that the micro structure 1023 increases the adhesion force between the fixing element 102 and the connecting element 103, and the fixing element 102 can be effectively fixed on the bottom plate 101 through the connecting element 103, thereby preventing rotation or loosening during screwing and locking. The microstructure 1023 of the embodiment is, for example, a spline structure, so that a concave-convex surface can be formed on the side surface of the first fixing end 1021a contacting the connecting element 103, and the connecting element 103 can be embedded into the microstructure 1023 of the first fixing end 1021a, thereby increasing the adhesion force between the connecting element 103 and the fixing element 102. Of course, the microstructure 1023 of the embodiment can be disposed on the surface of the fixing body 1021 of the fixing element 102 contacting with the connecting element 103, such as the side surface of the fixing flange 1022. In addition, the microstructure 1023 can also be formed on the side surface of the first fixing end 1021a or any part of the fixing element 102 that contacts the connecting element 103 to achieve the above-mentioned function. Microstructure 1023 of this embodiment can be applied to the base plate structures of other embodiments.

Please refer to fig. 9, which is a cross-sectional view of a bottom plate structure according to a sixth embodiment of the present invention; as shown in the drawings, the bottom plate structure 10 of the present embodiment is different from the bottom plate structure of the first embodiment in that the fixing flange 1022 of the fixing member 102 of the present embodiment further has at least one through hole 10221, and the bottom plate 101 has at least one third through hole 1013 penetrating through the first surface 101a and the second surface 101 b. Third via 1013 is located between first via 1011 and second via 1012 and corresponds to via 10221. The connecting element 103 has an auxiliary connecting portion 1034, the auxiliary connecting portion 1034 is located in the through hole 10221 of the fixing element 102 and the third through hole 1013 of the base plate 101 and connected to the first connecting end 1031 and the second connecting end 1032, so that the contact area of the connecting element 103 with the fixing element 102 and the base plate 101 is increased by the auxiliary connecting portion 1034, and the connecting element 103 can stably fix the fixing element 102 on the base plate 101. In this embodiment, the number of the through holes 10221 and the number of the third through holes 1013 are one, but it is understood that the number of the through holes 10221 and the number of the third through holes 1013 may be multiple, and the number of the through holes 10221 is consistent with the number of the third through holes 1013.

Please refer to fig. 10, which is a cross-sectional view of an electronic device according to a seventh embodiment of the present invention; as shown in the figure, the electronic device 2 of the present embodiment includes a casing 21, a key assembly 1 and a casing fixing member 22, wherein the casing 21 includes an upper casing and a lower casing, the key assembly 1 and the casing fixing member 22 are located between the upper casing and the lower casing, the casing 21 located above the casing fixing member 22 is the upper casing in the figure, and the casing 21 located below the casing fixing member 22 is the lower casing in the figure. The base plate structure 10 in the key assembly 1 can use the base plate structures of the first to sixth embodiments, and the base plate structure 10 of this embodiment is exemplified by the base plate structure of the first embodiment. The key assembly 1 is disposed in the casing 21, the bottom plate structure 10 is disposed in the casing 21, the casing 21 has a through hole 211, and the through hole 211 can be disposed in an upper casing or a lower casing of the casing 21, in this embodiment, the through hole 211 is disposed in the lower casing of the casing 21. The through-holes 211 correspond to the fixing holes 10211 of the fixing members 102 of the floor structure 10, and the case fixing members 22 may pass through the through-holes 211 and engage with the fixing holes 10211 to fix the floor structure 10 to the case 21. In this embodiment, the fixing holes 10211 are screw holes, the housing fixing members 22 are screws, and the housing fixing members 22 are locked in the fixing holes 10211. Of course, the housing fixing member 22 and the fixing hole 10211 are connected to each other by other connecting structures, and should not be limited thereto. The electronic device 2 of the embodiment is a keyboard, a notebook computer or other electronic devices requiring keys.

To sum up, the utility model provides a bottom plate structure, button subassembly and electron device, through the bottom plate that changes present button structure, through the bottom plate structure that uses bottom plate, mounting and connecting piece combination to form promptly, so can let the bottom plate in the bottom plate structure use slice, and the material of bottom plate is not limited to metal or nonmetal, not only can alleviate the holistic weight of bottom plate structure, has good connectivity simultaneously, lets the button subassembly that uses the bottom plate structure realize the lightweight, and then lets the electron device who uses the button subassembly realize the lightweight.

It should be noted that, in this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The embodiments of the present invention have been described with reference to the accompanying drawings, but the present invention is not limited to the above-mentioned embodiments, which are only illustrative and not restrictive, and those skilled in the art can make many forms without departing from the spirit and scope of the present invention.

Claims (19)

1. A floor structure, comprising:

a base plate having a first surface, a second surface, a first perforation and at least one second perforation, the first surface opposite the second surface, the first perforation and the at least one second perforation extending through the first surface and the second surface, the at least one second perforation located around the first perforation;

the fixing piece is positioned on the bottom plate, one part of the fixing piece is arranged in the first through hole, and the other part of the fixing piece extends towards the direction far away from the bottom plate; and

the connecting piece penetrates through the at least one second through hole and is arranged on the bottom plate, covers part of the first surface and the second surface, and covers part of the side surface of the fixing piece.

2. A floor structure according to claim 1, wherein another portion of said fastener extends perpendicularly from said floor.

3. A floor structure according to claim 1, wherein said floor is laminar.

4. The floor structure of claim 3, wherein the floor is made of carbon fiber or plastic.

5. The floor structure of claim 4, wherein said connector is made of plastic.

6. The floor structure according to claim 1, wherein the fixing member includes a fixing body and a fixing flange, the fixing flange being provided on a side surface of the fixing body and extending in a horizontal direction of the floor, a part of the fixing body being located in the first through hole, the fixing flange being located between the floor and the connecting member.

7. A floor structure according to claim 6, wherein said fixing member has a fixing hole provided in said fixing body, which is formed with a passage longitudinally penetrating or not penetrating said fixing body.

8. The floor structure of claim 7, wherein an inner wall of said channel of said fixing hole is formed with an internal thread.

9. A floor structure according to claim 6, wherein the fixing flange abuts against the first surface or the second surface of the floor, the fixing body protruding from the second surface or the first surface of the floor.

10. A floor structure according to claim 6, wherein said fixing body has a first fixing end portion and a second fixing end portion, said first fixing end portion and said second fixing end portion being located at both sides of said fixing flange, said second fixing end portion being located in said first through hole, said first fixing end portion protruding from said second surface or said first surface of said floor.

11. The floor structure according to claim 6, wherein the fixing flange is plural in number, and plural fixing flanges are provided at intervals on the side surface of the fixing body.

12. The floor structure of claim 6 wherein the surface of said fastener in contact with said attachment member further comprises microstructures.

13. A floor structure according to claim 6, wherein said connecting member has a first connecting end portion overlying said first surface of said floor, a second connecting end portion overlying said second surface of said floor and covering a side surface of said fixing member, and at least one connecting portion located in said at least one second aperture and connecting said first and second connecting end portions and covering said fixing flange.

14. The bottom plate structure of claim 13, wherein the fixing flange further has at least one through hole, the bottom plate further has at least one third through hole penetrating the first surface and the second surface, the at least one third through hole corresponding to the at least one through hole, and the connecting member further has at least one auxiliary connecting portion located in the at least one through hole and the at least one third through hole and connected to the first connecting end portion and the second connecting end portion.

15. The floor structure of claim 1, wherein said at least one second perforation is a circular hole, an arc-shaped hole, an elongated hole, or a slotted hole of any shape.

16. The floor structure of claim 15, wherein said at least one second perforation is a plurality of second perforations spaced around said first perforation.

17. A key assembly, comprising:

a floor structure as claimed in any one of claims 1 to 16;

the thin film circuit board is arranged on the bottom plate structure;

the elastic piece is arranged on the thin film circuit board;

the keycap is arranged on the elastic piece; and

and the lifting mechanism is arranged between the bottom plate structure and the keycap.

18. The key assembly of claim 17, further comprising a backlight module disposed on a surface of the base structure remote from the thin-film circuit board.

19. An electronic device, comprising:

a housing having a through hole;

the key assembly of claim 17, disposed on the housing, wherein the fixing member corresponds to the through hole; and

and the shell fixing piece penetrates through the through hole and is mutually jointed with the fixing hole of the fixing piece.

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