CN110854606A

CN110854606A - Buckle structure and casing

Info

Publication number: CN110854606A
Application number: CN201911197728.7A
Authority: CN
Inventors: 吴刚; 马腾飞; 敬文博; 黄瑞欣; 余学伟; 董奇奇; 温敏; 怀自力; 陈伟
Original assignee: Anhui Jianghuai Automobile Group Corp
Current assignee: Anhui Jianghuai Automobile Group Corp
Priority date: 2019-11-27
Filing date: 2019-11-27
Publication date: 2020-02-28
Anticipated expiration: 2039-11-27
Also published as: CN110854606B

Abstract

The invention discloses a buckle structure and a shell, wherein the buckle structure comprises: the positioning piece is provided with a first limiting plate and a second limiting plate, the first limiting plate and the second limiting plate are arranged at intervals to be matched to form a limiting gap, and the first limiting plate is provided with a limiting hole; the fastener comprises a main body plate and a clamping hook arranged on one surface of the main body plate; the main body plate and the clamping hook are inserted into the limiting gap, so that two opposite surfaces of the main body plate are respectively abutted to the opposite surfaces of the first limiting plate and the second limiting plate, the circumferential side wall of the clamping hook is abutted to the inner wall of the limiting hole of the first limiting plate, and the clamping hook is limited and fixed in the limiting hole. The technical scheme of the invention aims to improve the mounting precision of the buckle structure and improve the assembly and mounting efficiency of the buckle structure.

Description

Buckle structure and casing

Technical Field

The invention relates to the technical field of clamping, in particular to a clamping structure and a shell applying the same.

Background

The buckle is a structure used for the embedded connection or the integral locking of one part and another part, and is widely applied to various injection molding shells. Simple to operate directly presses can, need not the standard component, does not need extra mounting tool. The existing buckle is usually connected and matched by a positioning piece and a fastening piece, but the positioning piece and the fastening piece cannot be positioned completely during matching, and the buckle cannot be installed and fixed or is fixed and unstable after being easily dislocated, so that the buckle needs to be installed again, and the assembly and installation efficiency is reduced.

The above is only for the purpose of assisting understanding of the technical solutions of the present application, and does not represent an admission that the above is prior art.

Disclosure of Invention

The invention mainly aims to provide a buckle structure, aiming at improving the installation precision of the buckle structure and improving the assembly and installation efficiency of the buckle structure.

In order to achieve the above object, the present invention provides a buckle structure, including:

the positioning piece is provided with a first limiting plate and a second limiting plate, the first limiting plate and the second limiting plate are arranged at intervals to be matched to form a limiting gap, and the first limiting plate is provided with a limiting hole; and

the fastener comprises a main body plate and a clamping hook arranged on one surface of the main body plate;

the main body plate and the clamping hook are inserted into the limiting gap, so that two opposite surfaces of the main body plate are respectively abutted to the opposite surfaces of the first limiting plate and the second limiting plate, the circumferential side wall of the clamping hook is abutted to the inner wall of the limiting hole of the first limiting plate, and the clamping hook is limited and fixed in the limiting hole.

In an embodiment of the application, the positioning member further includes a connecting plate, and the first limiting plate and the second limiting plate are both connected to the same surface of the connecting plate.

In an embodiment of the application, the second limiting plate is equipped with spacing arch towards the protruding surface of first limiting plate, the main part board has been seted up and has been let a mouthful, the trip imbed in during spacing hole, spacing protruding insert and spacing in let a mouthful.

In an embodiment of the application, the limiting protrusion is provided with an abutting surface, and one end of the limiting protrusion, which is far away from the abutting surface, is connected with the connecting plate;

when the trip is embedded in the limiting hole, the abutting surface abuts against the surface of the main body plate facing the connecting plate.

In an embodiment of this application, spacing bellied cross section crescent in the direction of insertion, so that spacing bellied relative both sides face is used for the direction spacing arch inserts give way in the mouth.

In an embodiment of the application, a distance between an end of the first limiting plate away from the connecting plate and the connecting plate is defined as L1, a distance between an end of the second limiting plate away from the connecting plate and the connecting plate is defined as L2, and L1 > L2.

In an embodiment of this application, first limiting plate is including the portion of holding and connecting portion of being connected, connecting portion deviate from hold one side of portion with the connecting plate is connected, hold the portion and deviate from the thickness value of connecting portion one end is less than hold the portion and be close to the thickness value of connecting portion one end.

In an embodiment of the application, an end surface of the handling part departing from the connecting part is in an arc shape.

In an embodiment of the present application, a guiding inclined plane is formed on a side of the hook departing from the main body plate, and the guiding inclined plane guides the main body plate to be inserted into the limiting gap;

and/or, the main body plate and the clamping hook are of an integrated structure.

The application also provides a shell, which comprises an upper cover, a lower cover and a buckle structure, wherein the upper cover and the lower cover are respectively connected with the buckle structure, and the buckle structure is used for enabling the upper cover and the lower cover to be detachably connected. The buckle structure includes:

The buckle structure comprises a positioning piece and a fastening piece, wherein the positioning piece is provided with a first limiting plate and a second limiting plate which are arranged at intervals to form a limiting gap in a matched mode, and the first limiting plate is provided with a limiting hole; the fastener comprises a main body plate and a clamping hook arranged on one surface of the main body plate; so in the installation, insert spacing clearance with main part board and trip to make the relative two surfaces of main part board respectively the butt in the relative surface of first limiting plate and second limiting plate, with the removal of restriction main part board in the direction along first limiting plate or along the second limiting plate direction, restricted the removal of fastener fore-and-aft direction promptly, simultaneously through the circumference lateral wall of trip with first limiting plate in the inner wall butt in spacing hole, so that the trip is spacing to be fixed in spacing downthehole, thereby restricted the removal of direction about the fastener, and then make the fastener and the spacing complete fixation of setting element, in order to guarantee the fastening nature of buckle structural connection, simultaneously because the setting up of spacing clearance makes the user can accurately cooperate fastener and setting element fixed, improve the efficiency of operation.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

FIG. 1 is a schematic structural view of an embodiment of a fastening structure of the present invention;

FIG. 2 is a schematic view of an assembly structure of the buckle structure of the present invention;

FIG. 3 is a schematic structural view of a positioning member of the buckle structure of the present invention;

fig. 4 is a schematic structural view of a fastener of the snap structure of the invention.

The reference numbers illustrate:

reference numerals	Name (R)	Reference numerals	Name (R)
				100	Buckle structure	13	Spacing gap
10	Locating piece	131	Insertion section
				11	First limit plate	132	Fixed segment
111	Limiting hole	14	Connecting plate
				112	Operating part	141	Die drawing hole
113	Connecting part	20	Fastening piece
				12	Second limiting plate	21	Main board
121	Spacing protrusion	211	Let a mouthful
				1211	Abutting surface	22	Clamping hook
1212	Side surface	221	Guide slope

The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that all the directional indicators (such as up, down, left, right, front, and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the movement situation, etc. in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indicator is changed accordingly.

In the present invention, unless otherwise expressly stated or limited, the terms "connected," "secured," and the like are to be construed broadly, and for example, "secured" may be a fixed connection, a removable connection, or an integral part; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In addition, the descriptions related to "first", "second", etc. in the present invention are only for descriptive purposes and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and/or" appearing throughout is to include three juxtapositions, exemplified by "A and/or B," including either the A or B arrangement, or both A and B satisfied arrangement. In addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.

The present invention provides a snap structure 100.

Referring to fig. 1 and 2, in an embodiment of the present invention, the fastening structure 100 includes a positioning member 10 and a fastening member 20, the positioning member 10 is provided with a first limiting plate 11 and a second limiting plate 12, the first limiting plate 11 and the second limiting plate 12 are arranged at an interval to cooperate to form a limiting gap 13, and the first limiting plate 11 is provided with a limiting hole 111; the fastener 20 comprises a main body plate 21 and a clamping hook 22 arranged on one surface of the main body plate 21; the main body plate 21 and the hook 22 are inserted into the limiting gap 13, so that two opposite surfaces of the main body plate 21 are respectively abutted to opposite surfaces of the first limiting plate 11 and the second limiting plate 12, and the circumferential side wall of the hook 22 is abutted to the inner wall of the limiting hole 111 of the first limiting plate 11, so that the hook 22 is limited and fixed in the limiting hole 111.

The buckle structure 100 comprises a positioning piece 10 and a fastening piece 20, wherein the positioning piece 10 is provided with a first limiting plate 11 and a second limiting plate 12, the first limiting plate 11 and the second limiting plate 12 are arranged at intervals to form a limiting gap 13 in a matched manner, and the first limiting plate 11 is provided with a limiting hole 111; the fastener 20 comprises a main body plate 21 and a clamping hook 22 arranged on one surface of the main body plate 21; thus, during the installation process, the main body plate 21 and the hook 22 are inserted into the limiting gap 13, so that the two opposite surfaces of the main body plate 21 are respectively abutted against the opposite surfaces of the first limiting plate 11 and the second limiting plate 12, to restrict the movement of the main body plate 21 in the direction of the first restriction plate 11 or the movement in the direction of the second restriction plate 12, namely, the movement of the fastening member 20 in the front-rear direction is limited, and at the same time, the circumferential side wall of the hook 22 is abutted against the inner wall of the limiting hole 111 of the first limiting plate 11, so that the hook 22 is fixed in the limit hole 111 in a limited manner, thereby limiting the movement of the fastener 20 in the up-down, left-right directions, thereby, the fastening member 20 and the positioning member 10 are completely fixed in a limiting manner, so as to ensure the tightness of the connection of the buckle structure 100, meanwhile, due to the arrangement of the limiting gap 13, a user can accurately match and fix the fastener 20 and the positioning piece 10, and the operation efficiency is improved.

The positioning element 10 and the fastening element 20 can be made of plastic (such as ABS, POM, PS, PMMA, PC, PET, PBT, PPO, etc.), so that the stability of the connection between the positioning element 10 and the fastening element 20 can be ensured, and meanwhile, when the fastening element 20 is inserted into the positioning element 10, the first limiting plate 11 and the second limiting plate 12 are made of plastic, so that the first limiting plate 11 or the second limiting plate 12 can be shifted to be slightly deformed, and the main body plate 21 and the hook 22 can be easily clamped into the limiting gap 13; after the hook 22 is fixed in the limiting hole 111 in a limiting manner, the first limiting plate 11 or the second limiting plate 12 is elastically restored, so that the first limiting plate 11 and the second limiting plate 12 more stably clamp the main body plate 21, thereby ensuring stable connection between the positioning member 10 and the fastening member 20. It should be noted that the positioning member 10 and the fastening member 20 are respectively disposed at two parts to be connected, such as an upper cover and a lower cover of the housing, so as to facilitate installation and disassembly and improve the efficiency of connection. In addition, can also set up third limiting plate and fourth limiting plate on setting element 10, first limiting plate 11 is connected respectively towards the adjacent both sides face in surface of second limiting plate 12 to third limiting plate and fourth limiting plate, make third limiting plate and fourth limiting plate be located two openings that spacing clearance 13 is relative respectively, thereby be first limiting plate 11, second limiting plate 12, third limiting plate quarterly fourth limiting plate encloses spacing clearance 13 and closes formation accommodation space, make the user can be more accurate when connecting fastener 20 in setting element 10, improve the efficiency of installation.

Referring to fig. 1 to 3, in an embodiment of the present application, the positioning member 10 further includes a connection plate 14, and the first limit plate 11 and the second limit plate 12 are both connected to a same surface of the connection plate 14. Specifically, first limiting plate 11 and second limiting plate 12 can be respectively with connecting plate 14 structure as an organic whole, thereby guarantee the stability after fastener 20 and setting element 10 are connected, of course first limiting plate 11 and second limiting plate 12 also can dismantle and connect in connecting plate 14, thereby make things convenient for the maintenance in later stage to change, the fixed position of connecting the part that needs to be connected is connected through other fixed connection modes such as bonding with connecting plate 14 surface that deviates from first limiting plate 11, thereby can make setting element 10 fixed motionless, be connected fastener 20 and setting element 10 again. Because the contact area between the cross section of the connecting plate 14 and the component to be connected is relatively larger than that between the first limiting plate 11 and the second limiting plate 12, the positioning element 10 is positioned stably and is not easy to shake. It should be noted that, the first limiting plate 11 and the second limiting plate 12 may also be an integral structure, and then are connected to the connecting plate 14, so that the first limiting plate 11 and the second limiting plate 12 may independently form the limiting gap 13.

Further, the protruding spacing arch 121 that is equipped with in surface of second limiting plate 12 orientation first limiting plate 11, main part board 21 has been seted up and has been let a mouthful, trip 22 imbed in during spacing hole 111, spacing arch 121 insert and spacing in let a mouthful. Specifically, the limiting protrusion 121 may be integrated with the second limiting plate 12, so as to ensure the stability of the limiting protrusion 121 when abutting against the main body plate 21. Through being equipped with spacing arch 121 to when making main part board 21 insert spacing clearance 13 back along both sides removal, this main part board 21 is in the inner wall of stepping down the mouth and can be with the lateral wall butt of spacing arch 121, thereby further makes fastener 20 by the restriction removal in left and right directions, guarantees stability and the fastening nature after fastener 20 and setting element 10 are connected.

Furthermore, the limiting protrusion 121 is provided with an abutting surface 1211, and one end of the limiting protrusion 121, which is away from the abutting surface 1211, is connected to the connecting plate 14; when the hook 22 is inserted into the limiting hole 111, the abutment surface 1211 abuts against the surface of the main body plate 21 facing the connecting plate 14. Specifically, the limit protrusion 121 is provided with an abutting surface 1211, and one end of the limit protrusion 121, which is away from the abutting surface 1211, is connected to the connecting plate 14, so that when the main body plate 21 is inserted into the limit gap 13 and the hook 22 is inserted into the limit hole 111, the abutting surface 1211 abuts against the surface of the main body plate 21 facing the connecting plate 14, so that the main body plate 21 cannot move any more in the insertion direction, and the hook 22 is further limited and fixed in the limit hole 111, so as to maintain the stability after the fastening member 20 and the positioning member 10 are connected. Further, in order to facilitate production, the film pulling hole 141 is formed in the connecting plate 14, and the film pulling hole 141 is arranged towards the limiting hole 111 of the first limiting plate 11, so that the limiting hole 111 can be formed more conveniently when the die is used for production, a sliding block does not need to be additionally arranged to assist in opening the hole, and production cost is reduced.

Optionally, the cross section of the limiting protrusion 121 gradually increases in the insertion direction, so that the two opposite side surfaces 1212 of the limiting protrusion 121 are used for guiding the limiting protrusion 121 to be inserted into the abdicating hole. Specifically, because the cross section of the limiting protrusion 121 is gradually increased in the insertion direction, in the insertion process of the main body plate 21, the inner wall of the main body plate 21 at the abdicating opening abuts against the two opposite side surfaces 1212 of the limiting protrusion 121, so that the main body plate 21 can be positioned more accurately due to the guiding of the two side surfaces 1212 of the limiting protrusion 121, and the connection precision of the fastener 20 and the positioning element 10 is further ensured.

Referring to fig. 2, in an embodiment of the present application, a distance between an end of the first limiting plate 11 facing away from the connecting plate 14 and the connecting plate 14 is defined as L1, and a distance between an end of the second limiting plate 12 facing away from the connecting plate 14 and the connecting plate 14 is defined as L2, where L1 > L2. Specifically, because spacing hole 111 is located on first limiting plate 11, through making L1 be greater than L2 for the user can distinguish first limiting plate 11 and second limiting plate 12 more directly perceivedly, thereby makes the user can accurately insert trip 22 in spacing clearance 13 towards the direction of first limiting plate 11, has avoided the condition emergence that can't install after fastener 20 and setting element 10 misplace, and then in order to improve the efficiency of both installations. Of course, the first limit plate 11 may be provided with a marker for marking, which will not be described herein.

In an embodiment of this application, combine to refer to fig. 1 to 3, first limiting plate 11 is including the portion of holding 112 and connecting portion 113 that are connected, connecting portion 113 deviates from the portion of holding 112 one side with connecting plate 14 is connected, the portion of holding 112 deviates from the thickness value of connecting portion 113 one end is less than the portion of holding 112 is close to the thickness value of connecting portion 113 one end. The stopper hole 111 may be opened in the handling portion 112 or the connecting portion 113, or may be opened in a connecting portion between the handling portion 112 and the connecting portion 113, which may be selected by those skilled in the art. The operation part 112 and the connection part 113 may be integrally provided, so as to ensure stability during connection, and the thickness value of the end of the operation part 112 away from the connection part 113 is smaller than the thickness value of the end of the operation part 112 close to the connection part 113, because the first limit plate 11 needs to be deformed to facilitate insertion when the fastener 20 is inserted, so as to reduce the thickness of the operation part 112 to increase the elasticity of the operation part 112, and simultaneously, to ensure that the main body plate 21 is not easy to shake after being inserted into the limit gap 13 formed by the first limit plate 11 and the second limit plate 12, so as to increase the thickness value of the connection part 113, the thickness value of the end of the operation part 112 away from the connection part 113 is smaller than the thickness value of the end of the operation part 112 close to the connection part 113. In addition, the limit clearance 13 formed by the first limit plate 11 and the second limit plate 12 can be divided into an insertion section 131 and a fixed section 132, namely, the clearance formed by the handling part 112 and the second limit plate 12 is referred to as the insertion section 131, the clearance formed by the connecting part 113 and the second limit plate 12 is referred to as the fixed section 132, the insertion section 131 can be formed in a wedge shape, namely, the opening size of the limit clearance 13 is gradually reduced along the insertion direction, specifically, the surface of the second limit plate 12 facing the handling part 112 can be obliquely arranged along the direction deviating from the insertion direction, and the surface of the handling part 112 facing the second limit plate 12 is arranged in a plane, so that the insertion section 131 is formed in a wedge shape, and the resistance received by the main body plate 21 and the hook 22 when entering the insertion section 131 is smaller, so that the installation of the fastener 20 and the positioning element 10 is more convenient and the installation efficiency is faster; and the fixing segment 132 is used for ensuring the stability of clamping the main body plate 21, so that the second limit plate 12 and the connecting portion 113 are in plane abutment, so as to improve the contact area, so that the main body plate 21 is clamped more stably, and the stability of the fastening member 20 and the positioning member 10 after connection is further improved.

Further, an end surface of the handling portion 112 facing away from the connecting portion 113 is arc-shaped. It can be understood that, the user usually needs to stir the first limiting plate 11 to move along the direction departing from the second limiting plate 12, so as to insert the main body plate 21 and the hook 22 into the limiting gap 13 more conveniently, in order to improve the comfort of the user operation, the end surface of the operating part 112 departing from the connecting part 113 is in an arc-shaped configuration, thereby avoiding the possibility that the sharp edge of the operating part 112 may cause danger to the user, and improving the safety of use, and meanwhile, the end surface of the operating part 112 departing from the connecting part 113 is in an arc-shaped configuration, which also increases the contact area with the user, i.e., increases the friction force, so as to ensure the stability during operation.

In an embodiment of the present application, referring to fig. 1 and 4, a guiding inclined surface 221 is formed on a side of the hook 22 away from the main body plate 21, and the guiding inclined surface 221 guides the main body plate 21 to be inserted into the limiting gap 13; wherein this guide inclined plane 221 sets up along the slope of direction of insertion to when first limiting plate 11 contacts with trip 22, make first limiting plate 11 because the inclination of guide inclined plane 221 and along the direction removal that deviates from second limiting plate 12, thereby spacing clearance 13 increase, and then make main part board 21 and trip 22 insert more easily in spacing clearance 13. When the first limiting plate 11 is far from the end of the insertion direction at the guiding inclined plane 221, the main body plate 21 continues to move along the insertion direction, so that the hook 22 is completely inserted into the limiting hole 111, the first limiting plate 11 is restored to the original position due to the elastic effect, the limiting hole 111 is buckled on the hook 22, the hook 22 cannot move along the direction far from the insertion direction, and the installation of the fastener 20 and the positioning member 10 is completed.

Alternatively, the main body plate 21 and the hook 22 are integrally formed. Wherein make main part board 21 and trip 22 structure as an organic whole, not only saved the process of installation, improved the joint strength of main part board 21 and trip 22 simultaneously for the user grips main part board 21 and can drive trip 22 and remove, also guarantees the joint strength when fastener 20 and setting element 10 are connected.

The invention further provides a housing, which comprises an upper cover, a lower cover and a buckle structure 100, wherein the upper cover and the lower cover are respectively connected with the buckle structure 100, and the buckle structure 100 is used for detachably connecting the upper cover and the lower cover. Specifically, this buckle structure 100 includes setting element 10 and fastener 20, can be connected fastener 20 and upper cover, is connected setting element 10 and lower cover again to the stability of connecting can be guaranteed through the cooperation of fastener 20 and setting element 10 to upper cover and lower cover, and convenient the dismantlement again simultaneously, certainly also can be connected fastener 20 and lower cover, is connected setting element 10 and upper cover. Meanwhile, the specific structure of the buckle structure 100 refers to the above embodiments, and since the casing adopts all technical solutions of all the above embodiments, all beneficial effects brought by the technical solutions of the above embodiments are at least achieved, and are not repeated here.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. A snap structure, comprising:

2. The buckle structure of claim 1, wherein the positioning member further comprises a connecting plate, and the first and second limit plates are both connected to a same surface of the connecting plate.

3. The buckle structure according to claim 2, wherein a limiting protrusion is protruded from a surface of the second limiting plate facing the first limiting plate, the main body plate is provided with a relief opening, and when the hook is inserted into the limiting hole, the limiting protrusion is inserted into and limited by the relief opening.

4. The buckle structure according to claim 3, wherein the limiting protrusion is provided with an abutting surface, and one end of the limiting protrusion, which is far away from the abutting surface, is connected with the connecting plate;

5. The buckle structure of claim 3, wherein the cross section of the limiting protrusion gradually increases in the insertion direction, so that two opposite side surfaces of the limiting protrusion are used for guiding the limiting protrusion to be inserted into the receding port.

6. The buckle structure according to claim 2, wherein a distance between an end of the first limit plate facing away from the connecting plate and the connecting plate is defined as L1, a distance between an end of the second limit plate facing away from the connecting plate and the connecting plate is defined as L2, and L1 > L2.

7. The buckle structure according to claim 2, wherein the first limiting plate includes a holding portion and a connecting portion connected to each other, one side of the connecting portion away from the holding portion is connected to the connecting plate, and a thickness of the end of the holding portion away from the connecting portion is smaller than a thickness of the end of the holding portion close to the connecting portion.

8. The buckle structure of claim 7, wherein an end surface of the handling portion facing away from the connecting portion is arc-shaped.

9. The buckle structure according to any one of claims 1 to 8, wherein a guiding inclined surface is formed on a side of the hook facing away from the main body plate, and the guiding inclined surface guides the main body plate to be inserted into the limiting gap;

10. A housing comprising an upper cover, a lower cover and the snap structure of any one of claims 1 to 9, wherein the upper cover and the lower cover are respectively connected with the snap structure, and the snap structure is used for detachably connecting the upper cover and the lower cover.