Lamp structure

By designing the detachable threaded connection and the positioning slot structure of the housing, lamp and connecting parts in the lamp structure, the problems of complex lamp replacement and safety risks are solved, and convenient and safe lamp maintenance and replacement are achieved.

CN223411946UActive Publication Date: 2025-10-03FOSHAN DONNA LIGHTING
View PDF 0 Cites 0 Cited by

Patent Information

Application Number
CN202422982016.9
Authority / Receiving Office
CN · China
Patent Type
Utility models(China)
Current Assignee / Owner
Filing Date
2024-12-03
Publication Date
2025-10-03
Estimated Expiration
2034-12-03

AI Technical Summary

Technical Problem

The existing lamp replacement process is complex and difficult, requires professional tools or skills, and poses safety risks.

Method used

A lamp structure is designed, including a shell component, a lamp component and a connecting component. Through a detachable threaded connection and a locking groove structure, manual disassembly and replacement can be achieved, which simplifies the replacement process and improves stability.

Benefits of technology

The lamp replacement process is simplified, the difficulty and cost of replacement are reduced, the convenience and safety are improved, and the stability and versatility of the lamp structure are enhanced.

✦ Generated by Eureka AI based on patent content.

Smart Images

  • Figure CN223411946U_ABST
    Figure CN223411946U_ABST
Patent Text Reader

Abstract

The utility model relates to the technical field of lighting lamps, in particular to a lamp structure which comprises a shell part, a lamp part and a connecting part, the shell part covers the outer wall of the lamp part, the shell part is provided with a connecting hole, and the connecting part penetrates through the connecting hole and is connected with the lamp part through detachable threads. According to the lamp structure, the connecting component and the lamp component can be disassembled only by manually rotating the connecting component or the lamp component without using other professional tools or skills, so that the lamp component can be disassembled, maintained or replaced easily and conveniently, the replacement process of the lamp is simplified, the convenience of replacing the lamp is improved, and the cost is reduced. And the replacement difficulty and cost are reduced. Therefore, the lamp structure effectively solves the problems that in the prior art, the lamp replacement process is complex and difficult, and professional tools or skills are needed.
Need to check novelty before this filing date? Find Prior Art

Description

Technical Field

[0001] The utility model relates to the technical field of lighting lamps, and in particular to a lamp structure. Background Art

[0002] In modern life and work, lamps, as an important part of lighting equipment, not only undertake the basic function of providing light, but also gradually become a key factor in decorating space and creating atmosphere.

[0003] Traditional lighting designs often overlook the user's need for convenient maintenance, particularly when it comes to lamp replacement. Many existing lamps, whether for home or commercial use, are often complicated to replace, require specialized tools or skills, and present potential safety risks.

[0004] Specifically, replacing existing lamps typically involves removing screws and untangling complex wiring connections, a tedious and time-consuming task for users. Improper handling can also lead to lamp damage or safety hazards such as electric shock. Furthermore, for certain types of lamps, such as recessed ceiling lights and high-ceiling pendant lights, replacement becomes significantly more difficult and expensive.

[0005] Therefore, there is an urgent need to design a lamp structure that can simplify the lamp replacement process, reduce the difficulty and cost of replacement, while maintaining the beauty and practicality of the lamp, and meet users' needs for convenient lamp maintenance solutions. Utility Model Content

[0006] In view of this, the present invention provides a lamp structure for solving the problem in the prior art that the lamp replacement process is complicated, difficult, and requires professional tools or skills.

[0007] In order to solve the above technical problems, a technical solution adopted by the present invention is to provide a lamp structure, which includes a shell part, a lamp part and a connecting part. The shell part is covered on the outer wall of the lamp part. The shell part is provided with a connecting hole. The connecting part passes through the connecting hole and is connected to the lamp part by a detachable thread.

[0008] As an embodiment of the present utility model, the shell component includes an outer shell body, the inner wall of the outer shell body is formed with a first locking groove, the lamp component is locked into the first locking groove, the connecting hole is located at the top of the outer shell body, and the outer upper wall of the lamp component is abutted against the inner upper wall of the outer shell body.

[0009] As an embodiment of the present invention, the shell component also includes a first locking member and a second locking member, the first locking member and the second locking member are spaced apart on the inner side wall of the shell body, and form the first locking groove having a locking opening with the inner wall of the shell body, the lamp component is locked into the first locking groove from the locking opening, and the outer side wall of the lamp component is in contact with the first locking member and the second locking member.

[0010] As an embodiment of the present invention, the lamp component includes an inner shell body and a clamping foot, the clamping foot is provided at opposite ends of the outer upper wall of the inner shell body, and the clamping foot is clamped into the first clamping groove from the clamping mouth; the inner shell body is connected to the connecting component passing through the connecting hole, and the outer upper wall of the inner shell body is abutted against the inner upper wall of the outer shell body.

[0011] As an embodiment of the present invention, the lamp component further includes a snap ring, which is provided on the inner side wall of the inner shell body and forms a second snap groove with the inner wall of the inner shell body, and the second snap groove is used for installing the light-emitting body.

[0012] As an embodiment of the present invention, the connecting component includes a bolt member, a nut groove is provided on the top of the inner shell body, and the bolt member passes through the connecting hole and is connected to the nut groove.

[0013] As an embodiment of the present invention, the connecting component further includes a handheld piece, which is disposed on the top of the bolt member and forms an integrated structure, and the cross-sectional area of ​​the handheld piece is larger than the cross-sectional area of ​​the bolt member.

[0014] As an embodiment of the present invention, a plurality of grooves are formed on the outer side wall of the handpiece, and an inclined platform is formed between the outer side wall and the upper wall, and the inclined platform smoothly transitions to the grooves.

[0015] As an embodiment of the present invention, the bottom of the inner shell body protrudes from the bottom of the outer shell body.

[0016] As an embodiment of the present invention, the inner shell body and the outer shell body are both inverted cup-shaped structures, and the cross-sectional shapes of the inner shell body and the outer shell body are simultaneously any one of polygonal, circular and elliptical.

[0017] Compared with the prior art, the lamp structure provided by the embodiment of the present invention has the following advantages:

[0018] 1. The lamp structure provided by the present invention includes a housing component, a lamp component, and a connecting component. The housing component covers the outer wall of the lamp component, and the housing component defines a connecting hole. The connecting component passes through the connecting hole and is connected to the lamp component via a detachable threaded connection. The lamp structure can be disassembled from the lamp component simply by manually rotating the connecting component or the lamp component, without the need for other specialized tools or skills. This allows for easy and convenient disassembly, repair, or replacement of the lamp component, simplifying the lamp replacement process and reducing the difficulty and cost of replacement. This effectively solves the problem of the prior art that the lamp replacement process is complex, difficult, and requires specialized tools or skills.

[0019] 2. In the lamp structure provided by the present invention, the lamp component can be inserted into the first locking groove from the locking opening, and the outer wall of the lamp component can be abutted against the outer walls of the first locking member and the second locking member for stabilization, which can strengthen the connection between the lamp component and the shell component and improve the stability of the lamp structure.

[0020] 3. In the lamp structure provided by the present invention, the lamp component can be directly assembled with the shell component by inserting the clamping foot from the clamping opening of the shell component into the first clamping groove, thereby replacing the traditional method of disassembly and assembly that requires professional tools or skills, improving the convenience and simplicity of lamp maintenance and replacement, and improving the practicality of the lamp structure.

[0021] 4. In the lamp structure provided by the present invention, a second slot for installing the light-emitting body is formed by the clamping ring and the inner shell body. When only the light-emitting body needs to be replaced, there is no need to replace the lamp components together. The light-emitting body only needs to be rotated out or installed from the second slot to replace other light-emitting bodies, thereby improving the versatility of the lamp structure.

[0022] 5. In the lamp structure provided by the present invention, a bolt member is provided for connecting components and is connected to the top of the inner shell body with a nut groove. The inner shell body, i.e., the lamp component, can be disassembled and installed by hand without the use of other auxiliary tools, thereby improving the simplicity of lamp maintenance and replacement and reducing the safety risks of users replacing lamp components.

[0023] 6. In the lamp structure provided by the present invention, a handpiece is provided and connected to the top of the bolt part to form an integrated structure. The user can drive the rotation of the bolt part by rotating the handpiece, and the cross-sectional area of ​​the handpiece is larger than the cross-sectional area of ​​the bolt part, which can increase the force-bearing area of ​​the connecting part to a certain extent. The user can rotate the connecting part more effortlessly to achieve a threaded connection with the lamp part, and disassemble and replace the lamp part more effortlessly, thereby improving the maintenance efficiency of the lamp and also improving the user's satisfaction with the use of the lamp structure.

[0024] 7. In the lamp structure provided by the present invention, multiple grooves are formed on the outer wall of the handpiece, which can increase the friction between the handpiece and the user when rotating the handpiece, further saving the user's effort in disassembling the lamp components; in addition, a bevel is formed between the outer wall and the upper wall of the handpiece, and the bevel transitions smoothly to the groove, which can prevent the sharp edges of the handpiece from scratching the user's hands, further reducing the safety risks of the user replacing the lamp components, and improving the user's satisfaction with the lamp structure.

[0025] 8. In the lamp structure provided by the present invention, the outer shell body is sleeved on the outer periphery of the inner shell body, and the bottom of the inner shell body is configured to protrude from the bottom of the outer shell body, so that the inner shell body can be more conveniently removed when replacing lamp components, thereby improving the convenience of lamp replacement. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] in:

[0028] Figure 1 Shows a front view of the lamp structure provided by an embodiment of the utility model;

[0029] Figure 2 The three-dimensional structure of the housing component of the lamp structure provided by the embodiment of the utility model is shown Figure 1 ;

[0030] Figure 3 Shown Figure 1 Schematic diagram of the cross-sectional structure of the middle lamp structure from the AA perspective;

[0031] Figure 4 A schematic cross-sectional view of a housing component of a lamp structure provided by an embodiment of the present utility model is shown;

[0032] Figure 5 The three-dimensional structure of the housing component of the lamp structure provided by the embodiment of the utility model is shown Figure 2 ;

[0033] Figure 6 A schematic diagram of the three-dimensional structure of a lamp component of a lamp structure provided by an embodiment of the present utility model is shown;

[0034] Figure 7 A schematic cross-sectional view of a portion of the structure of a lamp provided by an embodiment of the present utility model is shown;

[0035] Figure 8 A schematic diagram of the three-dimensional structure of the connecting components of the lamp structure provided by an embodiment of the present utility model is shown.

[0036] Description of the accompanying drawings:

[0037] 1. Lamp structure;

[0038] 11. Housing parts; 12. Lamp parts; 13. Connecting parts;

[0039] 111, outer shell body; 112, first latching member; 113, second latching member; 114, latching opening; 115, first latching groove; 121, inner shell body; 122, latching foot; 123, snap ring; 124, second latching groove;

[0040] 131. Bolt; 132. Hand piece;

[0041] 1111, connecting hole; 1211, nut groove; 1321, groove; 1322, inclined platform. DETAILED DESCRIPTION

[0042] To facilitate understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The accompanying drawings provide embodiments of the present application. However, the present application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to make the disclosure of the present application more thorough and comprehensive.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application.

[0044] It is understood that the singular forms "a", "an", and "the" may also include plural forms, unless the context clearly indicates otherwise. It is also understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the possibility of the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

[0045] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only. In the present utility model, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inside", "outside", "center", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. These terms are mainly intended to better describe the present utility model and its embodiments, and are not intended to limit the indicated devices, elements or components to having a specific direction, or to be constructed and operated in a specific direction. In addition, in addition to being used to indicate directions or positional relationships, some of the above terms may also be used to indicate other meanings. For example, the term "upper" may also be used to indicate a certain dependency or connection relationship in certain circumstances. For those of ordinary skill in the art, the specific meanings of these terms in the present utility model can be understood according to the specific circumstances.

[0046] Furthermore, the terms "disposed," "provided with," "connected," and "connected" should be interpreted broadly. For example, they can refer to fixed connections, removable connections, or integral structures; mechanical connections or electrical connections; direct connections, indirect connections through an intermediary, or internal communication between two devices, elements, or components. Those skilled in the art will understand the specific meanings of these terms in this utility model based on specific circumstances.

[0047] See also Figure 1 and Figure 2 An embodiment of the present utility model discloses a lamp structure 1, which includes a shell part 11, a lamp part 12 and a connecting part 13. The shell part 11 is covered on the outer wall of the lamp part 12. The shell part 11 is provided with a connecting hole 1111. The connecting part 13 passes through the connecting hole 1111 and is connected to the lamp part 12 by a detachable thread.

[0048] Specifically, please combine Figure 2 and Figure 3 As shown, the lamp structure 1 is composed of three layers, the innermost layer is the lamp component 12, the middle layer is the shell component 11, and the outermost layer is the connecting component 13. The outermost connecting component 13 passes through the connecting hole 1111 of the middle layer shell component 11 and is detachably connected to the innermost lamp component 12.

[0049] It can be understood that the lamp structure 1 can be disassembled from the connecting member 13 and the lamp component 12 simply by manually rotating the connecting member 13 or the lamp component 12, without the need for other specialized tools or skills. This allows for easy and convenient disassembly, repair, or replacement of the lamp component 12, simplifying the lamp replacement process and reducing the difficulty and cost of replacement. Therefore, the lamp structure 1 provided by the present invention effectively solves the problems of the prior art in that the lamp replacement process is complex, difficult, and requires specialized tools or skills.

[0050] Furthermore, please combine Figures 3 to 5 As shown, the shell component 11 includes a shell body 111, and the inner wall of the shell body 111 is formed with a first locking groove 115. The lamp component 12 is locked into the first locking groove 115, and the connecting hole 1111 is located at the top of the shell body 111. The outer upper wall of the lamp component 12 abuts against the inner upper wall of the shell body 111.

[0051] Furthermore, the shell component 11 also includes a first locking member 112 and a second locking member 113. The first locking member 112 and the second locking member 113 are spaced apart on the inner wall of the shell body 111, and form a first locking groove 115 with the inner wall of the shell body 111 having a locking opening 114. The lamp component 12 is locked into the first locking groove 115 from the locking opening 114, and the outer side wall of the lamp component 12 is in contact with the first locking member 112 and the second locking member 113.

[0052] Specifically, the shape of the outer wall of the first locking member 112 and the second locking member 113 matches the shape of the inner wall of the shell body 111, and they are spaced apart on the inner wall of the shell body 111, that is, the outer walls of the first locking member 112 and the second locking member 113 are connected to the inner wall of the shell body 111, and two locking openings 114 are formed at both ends of the first locking member 112 and the second locking member 113. There is a spatial gap between the first locking member 112 and the second locking member 113 and the inner upper wall of the shell body 111, thereby forming a first locking groove 115, and the first locking groove 115 has a locking opening 114 that can be entered and exited, so that the lamp component 12 can be inserted into the first locking groove 115 from the locking opening 114, and the outer wall of the lamp component 12 is abutted against the outer wall of the first locking member 112 and the second locking member 113 for stabilization. By snapping the lamp component 12 into the first snap-in groove 115 of the housing body 111 , the connection between the lamp component 12 and the shell component 11 is strengthened, thereby improving the stability of the lamp structure 1 .

[0053] Furthermore, please combine Figure 3 、 Figure 6 and Figure 7As shown, the lamp component 12 includes an inner shell body 121 and a clamping foot 122, and the clamping foot 122 is provided at opposite ends of the outer upper wall of the inner shell body 121, and the clamping foot 122 is clamped into the first clamping groove 115 from the clamping opening 114; the inner shell body 121 is connected to the connecting component 13 passing through the connecting hole 1111, and the outer upper wall of the inner shell body 121 abuts against the inner upper wall of the outer shell body 111.

[0054] Specifically, the lamp component 12 has two clips 122, which are arranged at opposite ends of the outer upper wall of the inner shell body 121. The lamp component 12 can be directly assembled with the shell component 11 by inserting the two clips 122 from the two clip openings 114 of the shell component 11 into the first clip groove 115, replacing the traditional method of disassembly and assembly that requires professional tools or skills, thereby improving the convenience and simplicity of lamp maintenance and replacement, and improving the practicality of the lamp structure 1.

[0055] Further, see Figure 7 As shown, the lamp component 12 further includes a snap ring 123 , which is disposed on the inner side wall of the inner shell body 121 and forms a second snap groove 124 with the inner wall of the inner shell body 121 . The second snap groove 124 is used to mount the light-emitting body.

[0056] Specifically, a second slot for installing the light-emitting body is formed by the retaining ring 123 and the inner shell body 121. When only the light-emitting body needs to be replaced, there is no need to replace it together with the lamp component 12. The light-emitting body only needs to be rotated out or installed from the second retaining slot 124 to replace other light-emitting bodies, thereby improving the versatility of the lamp structure 1.

[0057] Furthermore, please combine Figure 3 、 Figure 7 and Figure 8 As shown, the connecting component 13 includes a bolt 131 , and a nut groove 1211 is formed on the top of the inner shell body 121 . The bolt 131 passes through the connecting hole 1111 and is connected to the nut groove 1211 .

[0058] Specifically, the bolt 131 is a component for realizing spiral connection between common structures. It is used to connect the component 13 and is connected to the top of the inner shell body 121 with a nut groove 1211. The inner shell body 121, i.e., the lamp component 12, can be disassembled and installed by hand without the use of other auxiliary tools, thereby improving the ease of lamp maintenance and replacement and reducing the safety risks of users replacing the lamp component 12.

[0059] Furthermore, please combine Figure 7 and Figure 8As shown, the connecting component 13 further includes a hand piece 132 , which is disposed on the top of the bolt member 131 and forms an integral structure. The cross-sectional area of ​​the hand piece 132 is larger than the cross-sectional area of ​​the bolt member 131 .

[0060] Specifically, a handpiece 132 is provided and connected to the top of the bolt member 131 to form an integrated structure. The user can drive the rotation of the bolt member 131 by rotating the handpiece 132, and the cross-sectional area of ​​the handpiece 132 is larger than the cross-sectional area of ​​the bolt member 131, which can increase the force-bearing area of ​​the connecting component 13 to a certain extent. The user can rotate the connecting component 13 more effortlessly to achieve a threaded connection with the lamp component 12, and disassemble and replace the lamp component 12 more effortlessly, thereby improving the maintenance efficiency of the lamp and also improving the user's satisfaction with the use of the lamp structure 1.

[0061] Furthermore, a plurality of grooves 1321 are formed on the outer wall of the handpiece 132 , and an inclined platform 1322 is formed between the outer wall and the upper wall, and the inclined platform 1322 smoothly transitions to the grooves 1321 .

[0062] Specifically, a plurality of grooves 1321 are formed on the outer wall of the handpiece 132, which can increase the friction between the user and the handpiece 132 when the user rotates the handpiece 132, further saving the user's effort in disassembling the lamp component 12; in addition, a sloped platform 1322 is formed between the outer wall and the upper wall of the handpiece 132, and the sloped platform 1322 smoothly transitions to the groove 1321, which can prevent the sharp edges of the handpiece 132 from scratching the user's hands, further reducing the safety risks of the user when replacing the lamp component 12, and improving the user's satisfaction with the lamp structure 1.

[0063] Furthermore, the bottom of the inner shell body 121 protrudes from the bottom of the outer shell body 111 .

[0064] Specifically, since the outer shell body 111 is sleeved around the outer periphery of the inner shell body 121, and the bottom of the inner shell body 121 is configured to protrude from the bottom of the outer shell body 111, the inner shell body 121 can be more conveniently removed when replacing the lamp component 12, thereby improving the convenience of lamp replacement.

[0065] Optionally, the inner shell body 121 and the outer shell body 111 are both inverted cup-shaped structures, and the cross-sectional shapes of the inner shell body 121 and the outer shell body 111 are simultaneously any one of polygonal, circular and elliptical.

[0066] Specifically, the cross-sectional shapes of the inner shell body 121 and the outer shell body 111 are simultaneously various shapes, which can be configured to match different light-emitting body shapes, thereby improving the versatility of the lamp structure 1. In the embodiment of the present invention, the cross-sectional shapes of the inner shell body 121 and the outer shell body 111 are both circular for specific description.

[0067] More specifically, the inner shell body 121 and the outer shell body 111 are both inverted cylindrical cup-shaped structures. The outer shell body 111 is mounted on the outside of the inner shell body 121, and then the bolt 131 of the connecting component 13 passes through the connecting hole 1111 of the outer shell body 111, and finally connected to the nut groove 1211 of the inner shell body 121 to realize the installation and disassembly of the lamp component 12.

[0068] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0069] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that a person skilled in the art could make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A lamp structure, characterized in that: The lamp structure includes a shell component, a lamp component and a connecting component. The shell component is covered on the outer wall of the lamp component. The shell component is provided with a connecting hole. The connecting component passes through the connecting hole and is connected to the lamp component via a detachable thread.

2. The lamp structure according to claim 1, characterized in that: The shell component includes a shell body, the inner wall of the shell body is formed with a first clamping groove, the lamp component is clamped into the first clamping groove, the connecting hole is located at the top of the shell body, and the outer upper wall of the lamp component abuts against the inner upper wall of the shell body.

3. The lamp structure according to claim 2, characterized in that: The shell component also includes a first locking member and a second locking member, the first locking member and the second locking member are spaced apart on the inner wall of the shell body, and form the first locking groove with a locking opening with the inner wall of the shell body, the lamp component is locked into the first locking groove from the locking opening, and the outer side wall of the lamp component abuts against the first locking member and the second locking member.

4. The lamp structure according to claim 3, characterized in that: The lamp component includes an inner shell body and a clamping foot, the clamping foot is provided at opposite ends of the outer upper wall of the inner shell body, and the clamping foot is clamped into the first clamping groove from the clamping mouth; the inner shell body is connected to the connecting component passing through the connecting hole, and the outer upper wall of the inner shell body abuts against the inner upper wall of the outer shell body.

5. The lamp structure according to claim 4, characterized in that: The lamp component further includes a snap ring, which is provided on the inner side wall of the inner shell body and forms a second snap groove with the inner wall of the inner shell body, and the second snap groove is used for mounting the light-emitting body.

6. The lamp structure according to claim 4, characterized in that: The connecting component includes a bolt member, a nut groove is opened on the top of the inner shell body, and the bolt member passes through the connecting hole and is connected to the nut groove.

7. The lamp structure according to claim 6, characterized in that: The connecting component further includes a handheld piece, which is arranged on the top of the bolt piece and forms an integrated structure. The cross-sectional area of ​​the handheld piece is larger than the cross-sectional area of ​​the bolt piece.

8. The lamp structure according to claim 7, characterized in that: A plurality of grooves are formed on the outer side wall of the hand piece, and an inclined platform is formed between the outer side wall and the upper wall, and the inclined platform smoothly transitions to the grooves.

9. The lamp structure according to claim 4, characterized in that: The bottom of the inner shell body protrudes from the bottom of the outer shell body.

10. The lamp structure according to claim 4, characterized in that: The inner shell body and the outer shell body are both inverted cup-shaped structures, and the cross-sectional shapes of the inner shell body and the outer shell body are simultaneously any one of polygonal, circular and elliptical.