US20160060013A1

US20160060013A1 - Protecting device and stretchable member thereof

Info

Publication number: US20160060013A1
Application number: US14/692,336
Authority: US
Inventors: Li-Chun Hsu
Original assignee: TPV-INVENTA TECHNOLOGY Co Ltd
Current assignee: TPV-INVENTA TECHNOLOGY Co Ltd
Priority date: 2014-08-27
Filing date: 2015-04-21
Publication date: 2016-03-03
Also published as: TWM492890U

Abstract

A protecting device for placing an object includes two connecting members and two stretchable members. The two stretchable members are attached between the two connecting members to enclose an accommodating space. Each of the stretchable members includes a first block, a second block and two joint units. The first block includes a first linking part. The second block includes a recess portion located between two second linking parts. The two first ends of the joint unit are attached with each other and attached to the first linking part. The two second ends of the joint unit are separated with each other and attached to the second linking parts, respectively. When the stretchable members are at the retracted state, part of the joint unit is located inside the recess portion, and the joint unit is located outside the recess portion at the extended state.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This non-provisional application claims priority under 35 U.S.C. §119(a) on Patent Application No(s). 103215363 filed in Taiwan, R.O.C. on Aug. 27, 2014, the entire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Technical Field
The disclosure relates to a protecting device and stretchable member thereof, more particular to a protecting device and stretchable member thereof for placing an object with different size.
2. Background
During the transportation of electronic device, protecting devices are used for surrounding the electronic device for protecting the electronic device from collision. The shape of the electronic device is different, thus protecting devices with different size are needed for the electronic devices with different shapes. However, preparing different molds for manufacturing protecting devices with different sizes increases the manufacturing cost.
Therefore, some manufacturers set a stretchable bellows-type piece in the protecting device for the electronic devices with different sizes. However, continuous Z-shape side surface of the stretchable bellows-type piece with variable stretching range cannot be fixed at a certain range to satisfy demands of users. When the stretchable piece extends too long, the protecting piece is easily detached from the electronic device.

SUMMARY

One embodiment of the present disclosure discloses a protecting device for placing an object. The protecting device comprises two connecting members and two stretchable members. The two stretchable members each are attached between the two connecting members. The two stretchable members and the two connecting members enclose together to form an accommodating space which is for placing the object. Each of the stretchable members has a retracted state and an extended state. Each of the stretchable members comprises a first block, a second block and two first join units. The first block comprises a first linking part. The second block comprises two second linking parts separated with each other, and a first recess portion located between the two second linking parts. The two first join units each comprises a first end and a second end that are opposite to each other. The two first ends are attached with each other and attached to the first linking part. The two second ends are separated with each other and attached to the two second linking parts, respectively. Twice a length between the first end and the second end of each first join unit is longer than a straight-line between the two second linking parts. When the stretchable members are at the retracted state, at least part of each of the first joint unit is located inside the first recess portion. When the stretchable members are at the extended state, each of the first joint unit is located outside the first recess portion.
Another embodiment of the present disclosure discloses a stretchable member having a refracted state and an extended state comprises a first block, a second block and two joint units. The first block comprises a first linking part. The second block comprises two second linking parts separated with each other, and a recess portion located between the two second linking parts. Two join units each comprises a first end and a second end that are opposite to each other. The two first ends are attached with each other and attached to the first linking part. The two second ends are separated with each other and attached to the two second linking parts, respectively. Twice a length between the first end and the second end of each of the joint units is longer than a straight-line between the two second linking parts. When the stretchable member is at the retracted state, at least part of each of the joint unit is located inside the recess portion. When the stretchable member is at the extended state, each of the joint unit is located outside the recess portion.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more fully understood from the detailed description given herein below, along with the accompanying drawings which are for illustration only, thus are not limitative of the present disclosure, and wherein:

FIG. 1A is a perspective view of a protecting device with a first object inside according to an embodiment of the disclosure;

FIG. 1B is a perspective view of a protecting device with a second object inside according to the embodiment of the disclosure;

FIG. 2A and FIG. 2B are side views of the stretchable member of the protecting device at a retracted state in FIG. 1A according to the embodiment of the disclosure;

FIG. 2C is a side view of the stretchable member of the protecting device at an extended state in FIG. 1B according to the embodiment of the disclosure;

FIG. 3A is a perspective view of a protecting device with a third object inside according to another embodiment of the disclosure;

FIG. 3B is a perspective view of a protecting device with a fourth object inside according to the embodiment of the disclosure;

FIG. 4A is a side view of the stretchable member of the protecting device at a retracted state in FIG. 3A according to the embodiment of the disclosure; and

FIG. 4B is a side view of the stretchable member of the protecting device at a first extended state in FIG. 3B according to the embodiment of the disclosure.

DETAILED DESCRIPTION

In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.
The following descriptions of the present disclosure, protecting device, are referring to FIG. 1A and FIG. 1B, wherein FIG. 1A is a perspective view of two protecting devices 1, 1′ with a first object 21 inside according to an embodiment of the disclosure, and FIG. 1B is a perspective view of two protecting devices 1, 1′ with a second object 22 inside according to the embodiment of the disclosure. The length L1 of the first object 21 is smaller than the length L2 of the second object 22. In addition, the distance between the protecting device 1 and 1′ is adjustable for fitting the width of the first object 21 or the second object 22. In this embodiment, the one protecting device 1 protects one side of the first object 21 or the second object 22, and the other protecting device 1′ protects another side of the first object 21 or the second object 22. The first object 21 and the second object 22 are the object protected by the protecting device. For example, the object is an electronic device. Because the structures of the protecting device 1 and the protecting device 1′ are similar, the following descriptions focus on the protecting device 1 and the description of the protecting device 1′ will not be repeated.
The protecting device 1 comprises two connecting members 11, two stretchable members 12 and two covering members 13. The two stretchable members 12 are attached between the two connecting members 11. The two stretchable members 12 and the two connecting members 11 enclose together to form an accommodating space 10. The accommodating space 10 is used for placing the first object 21 or the second object 22. The covering members is set on the connecting members respectively for covering portions of the first subject 21 or the second subject 22. Each of the stretchable members 12 includes a retracted state and an extended state according to the different positions and shapes of the stretchable members. When the stretchable members 12 are at the retracted state, as shown in FIG. 1A, the first object 21 is able to be put in the accommodating space 10 since the size of the accommodating space 10 at the retracted state matches with that of the first object 21. When the stretchable members 12 are at the extended state, as shown in FIG. 1B, the second object 22 is able to be put in the accommodating space 10 since the size of the accommodating space 10 at the extended state matches with that of the second object 22. Furthermore, the structure of the stretchable members 12 are able to be applied to not only the protecting device 1 of the disclosure but also other components with variable lengths.
Please refer to FIG. 2A, FIG. 2B and FIG. 2C, FIG. 2A and FIG. 2B are side views of the stretchable member 12 of the protecting device 1 at a retracted state in FIG. 1A according to the embodiment of the disclosure. FIG. 2C is a side view of the stretchable member of the protecting device at a extended state in FIG. 1B according to the embodiment of the disclosure. The following describes the detailed structure of the stretchable member 12. The side view of the stretchable member 12 of the protecting device 1 at the retracted state is divided into FIG. 2A and FIG. 2B to avoid the symbols of the elements in one figure becoming too complicated. The upper side and lower side of the stretchable member 12 in FIG. 2A to FIG. 2C are substantially symmetrical, In order to avoid the numerals in each figure becoming too complicated, the repeated numerals of the elements only are labeled on one side of the stretchable member 12.
The stretchable members 12 comprise a first block 121, a second block 122 and two joint units 123. The first block 121 comprises a first linking part 1211. The second block 122 comprises two second linking parts 1221 separated with each other by a distance and a recess portion 1222 located between the two second linking parts 1221. Each of the joint units 123 has a first end 1231 and a second end 1232 that are opposite to each other. The two first ends 1231 are attached with each other and both of them are attached to the first linking part 1211. The two second ends 1232 are separated with each other by a distance and attached to the two second linking parts 1221, respectively. Twice a length L3 between the first end 1231 and the second end 1232 is longer than a straight-line L4 between the two second linking parts 1221. As shown in FIG. 2A and FIG. 2B, when the stretchable members 12 are at the refracted state, at least part of each of the joint units 123 is located inside the recess portion 1222. As shown in FIG. 2C, when the stretchable members 12 are at the extended state, each of the joint unit 123 is located outside the recess portion 1222.
As shown in FIG. 2A and FIG. 2B, when the stretchable members 12 are at the retracted state, due to twice the length L3 between the first end 1231 and the second end 1232 being longer than a straight-line L4 between the two second linking parts 1221 and each of the joint units 123 located inside the recess portion 1222, the joint units 123 are not easy to leave the recess portion 1222. Thus, when the stretchable members 12 are at the retracted state, the distance between the first block 121 and the second block 122 is uneasy to vary.
When the first block 121 from the second block 122 are pulled by a certain force for separating them with each other, the shapes of the joint units 123 are changed at a certain degree. Each of the joint units 123 is pulled out of the recess portion 1222 and rotated with respect to the first block 121 and the second block 122, which makes the stretchable members 12 transform from the retracted state to the extended state shown in FIG. 2C. Due to twice the length L3 between the first end 1231 and the second end 1232 being longer than the straight-line L4 between the two second linking parts 1221, it is uneasy for each of the joint units 123 to return to the recess portion 1222. Further, when the stretchable members 12 are at the extended state, the two first ends 1231 of the joint units 123 are pressed against each other and even produce a compressed area 1231 a, which stops each of the joint units 123 rotating with respect to the first block 121 and then limits the first block 121 to be pulled away from the second block 122. As a result, the distance between the first block 121 and the second block 122 of the stretchable members 12 at the extended state is longer than that of the stretchable members 12 at the retracted state. The distance between the first block 121 and the second block 122 of the stretchable members 12 is uneasy to vary, which means the stretchable members 12 keep at the retracted state or the stretched state.
When the first block 121 and the second block 122 are pressed by a certain force F for making them become closer, the shapes of the joint units 123 are changed at a certain degree. Each of the joint units 123 is pressed back into the interior of the recess portion 1222 and the stretchable members 12 transforms to the retracted state shown in FIG. 2A and FIG. 2B. Therefore, the distance between the first block 121 and the second block 122 of the stretchable members 12 is uneasy to vary, which means the stretchable members 12 keep at the retracted state or the extended state.
The manufacturing procedure of the stretchable members 12 of the this embodiment includes that the first block 121, the second block 122 and the two join units 123 are segmented from a main block 120 which, for example, is made by foamed material. As shown in FIG. 2A and FIG. 2B, the main block 120 has two side surfaces 1200 that are opposite to each other, two first cutting surfaces 1201, two second cutting surfaces 1202, two third cutting surfaces 1203 and two fourth cutting surfaces 1204. The join units 123 are formed by each of the first cutting surfaces 1201, each of the second cutting surfaces 1202, each of the third cutting surfaces 1203 and each of the fourth cutting surfaces 1204 together.
Each of the first cutting surfaces 1201 and each of the fourth cutting surfaces 1204 extend from the side surfaces 1200 toward an interior of the main block 120. Each of the second cutting surfaces 1202 and each of the third cutting surfaces 1203 are separated from the side surfaces 1200 by a distance, respectively. The third cutting surfaces 1203 are connected with the first ends 1231, respectively. The fourth cutting surfaces 1204 are connected with the second ends 1232, respectively.
When the stretchable members 12 are at the retracted state, the joint units 123 and the first blocks 121 are divided by the first cutting surfaces 1201. The fourth cutting surfaces 1204 are connected with but do not across the first cutting surfaces 1201. The joint units 123 and the second block 122 are divided by the second cutting surfaces 1202 and the third cutting surfaces 1203. The two third cutting surfaces 1203 are connected with each other, and the second cutting surfaces 1202 are connected with but do not across the third cutting surfaces 1203.
Each of the join units 123 has a first angle θ1 formed by a connection of the second cutting surfaces 1202 and the third cutting surfaces 1203. The first angle θ1 is greater than or equal to 90 degrees and less than 150 degrees. The first angle θ1 determines the compressed degree of the compressed area 1231 a of the two first ends 1231 of the two joint units 123 when the stretchable members 12 are at the extended state (as shown in FIG. 2C). The smaller the first angle θ1 is, the larger the compressed area is. Each of the joint units has a second angle θ2 formed by a connection of the first cutting surfaces 1201 and the fourth cutting surfaces 1204. The second angle θ2 is greater than or equal to 90 degrees and less than 150 degrees. When the stretchable members 12 are at the retracted state, the first cutting surfaces 1201 are substantially paralleled to the second cutting surfaces 1202. The third cutting surfaces 1203 are substantially paralleled to the fourth cutting surfaces 1204.
The width between the two side surfaces 1200 of the main block 120 is X. When the stretchable members 12 are at the retracted state, the distance between a connecting position of each of the first cutting surfaces 1201 and each of the side surfaces 1200 and a connecting position of each of the fourth cutting surfaces 1204 and each of the side surfaces 1200 is Y. The length of each of the first cutting surfaces 1201 is Z. The distance between each of the first cutting surfaces 1201 and each of the second cutting surfaces 1202 is M. The length of each of the second cutting surfaces 1202 is N. The length of each of the third cutting surfaces 1203 is P. The length of each of the fourth cutting surfaces 1204 is Q. The distance between each of the ends of the second cutting surfaces 1202 and each of the fourth cutting surfaces 1204 is R. When the stretchable members 12 are at the extended state, the distance between a connecting position of each of the first cutting surfaces 1201 and each of the side surfaces 1200 and a connecting position of each of the fourth cutting surfaces 1204 and each of the side surfaces 1200 is T. And the protecting device 1 satisfies the following conditions: X/2<Z<2X/3; Q=Z/2; P=Q/2; Z/2<N<2Z/3; M=Q/2; Y<X/2; R=Z−N; and T=3Y/2.
Please refer to FIG. 3A and FIG. 3B, FIG. 3A, FIG. 3A is a perspective view of two protecting devices 3, 3′ with a third object 41 inside according to another embodiment of the disclosure, and FIG. 3B is a perspective view of two protecting devices 3, 3′ with a fourth object 42 inside according to the embodiment of the disclosure. In this embodiment, the length L5 of the third object 41 is smaller than the length L6 of the fourth object 42. In addition, the distance between the protecting device 3 and 3′ is adjustable for fitting the width of the third object 41 or the fourth object 42. In this embodiment, the one protecting device 3 protects one side of the third object 41 or the fourth object 42, and the other protecting device 3′ protects another side of the third object 41 or the fourth object 42. Because the structures of the protecting device 3 and the protecting device 3′ are similar, the following descriptions focus on the protecting device 3 and the description of the protecting device 3′ will not be repeated.
The protecting device 3 comprises two connecting members 31, two stretchable members 32 and two covering members 33. The two stretchable members 32 are attached between the two connecting members 31. The two stretchable members 32 and the two connecting members 31 enclose together to form an accommodating space 30. The accommodating space 30 is used for placing the third object 41 or the fourth object 42. The covering members 33 is set on the connecting members 31 respectively for covering portions of the third object 41 or the fourth object 42. Each of the stretchable members 32 includes a retracted state, a first extended state and a second extended state according to the different positions and shapes of the stretchable members. When the stretchable members 32 are at the retracted state, as shown in FIG. 3A, the third object 41 is able to be put in the accommodating space 30 since the size of the accommodating space 30 at the retracted state matches with that of the third object 41. When the stretchable members 12 are at the first extended state, as shown in FIG. 3B, the fourth object 42 is able to be put in the accommodating space 30 since the size of the accommodating space 30 at the first extended state matches with that of the fourth object 42. Moreover, when the stretchable members 12 are at the second extended state (not shown), the fifth object (not shown), which has a length between the length of the third object 41 and the length of the fourth object 42, is able to be put in the accommodating space 30 since the size of the accommodating space 30 at the second extended state matches with that of the fifth object.
Please refer to FIG. 4A and FIG. 4B, FIG. 4A is side view of the stretchable member 32 of the protecting device 3 at a retracted state in FIG. 3A according to the embodiment of the disclosure. FIG. 4B is a side view of the stretchable member of the protecting device 3 at a first extended state in FIG. 3B according to the embodiment of the disclosure. The following describes the detailed structure of the stretchable members 32. The upper side and lower side of the stretchable member 32 in FIG. 4A and FIG. 4B are substantially symmetrical. In order to avoid the numerals in each figure becoming too complicated, the repeated numerals of the elements only are labeled on one side of the stretchable member 32.
The stretchable members 32 comprise a first block 321, a second block 322, two first joint units 323, a third block 324 and two second joint units 325. The first block 321 comprises a first linking part 3211. The second block 322 comprises two second linking parts 3221, one first recess portion 3222, two third linking parts 3223 and a second recess portion 3224. The two second linking parts 3221 are separated with each other by a distance, and the first recess portion 3222 is located between the two second linking parts 3221. The two third linking parts 3223 are opposite to the two second linking parts 3221 and separated with each other by a distance, and the second recess portion 3224 is located between the two third linking parts 3223.
Each of the first joint units 323 has a first end 3231 and a second end 3232 that are opposite to each other. The two first ends 3231 are attached with each other and both of them are attached to the first linking part 3211. The two second ends 3232 are separated with each other and both of them are attached to the two second linking parts 3221 respectively.
The third block 324 comprises a fourth linking part 3241. Each of the second joint units 325 has a third end 3251 and a fourth end 3252 that are opposite to each other. The two third ends 3251 are separated with each other and both of them are attached to the two third linking parts 3223 respectively. The two fourth ends 3252 are attached with each other and attached to the fourth linking part 3241. As shown in FIG. 4A, when the stretchable members 32 are at the retracted state, at least part of each of the first joint units 323 is located inside the first recess portion 3222, and at least part of each of the second joint units 325 is located inside the second recess portion 3224. As shown in FIG. 4B, when the stretchable members 32 are at the first extended state, each of the first joint units 323 is located outside the first recess portion 3222, and each of the second joint units 325 is located outside the second recess portion 3224. When the stretchable members 32 are at the second extended state (not shown), each of the first joint units 323 is located outside the first recess portion 3222, and each of the second joint units 325 is located inside the second recess portion 3224; or each of the first joint units 323 is located inside the first recess portion 3222, and each of the second joint units 325 is located outside the second recess portion 3224.
The operation manner, manufacturing method and relative portions of size of the first block 321, the second block 322 and the two first joint units 323 in the present embodiment are similar to those of the first block 121, the second block 122 and the two joint units 123 in the embodiment shown in FIG. 2A to FIG. 2C, so the similar parts are not repeated herein. Moreover, the operation manner, manufacturing method and relative portions of size of the third block 324, the second block 322 and the two second joint units 325 in the present embodiment are similar to those of the first block 121, the second block 122 and the two joint units 123 in the embodiment shown in FIG. 2A to FIG. 2C, so the similar parts are not repeated herein, too.
According to the protecting device with stretchable member disclosed in the embodiments of the disclosure, twice the distance between each of the first ends of the joint units and each of the second ends of the joint units is longer than the straight-line between each of the second linking parts of the second block, which makes the joint units uneasy to leave the recess portion and the distance between the first block and the second block uneasy to be changed when the stretchable members are in the retracted state. Moreover, the distance between the first block and the second block of the stretchable members at the extended state is longer than the distance between the first block and the second block of the stretchable members at the retracted state. The two first ends of the two joint units are pressed against each other, which makes the first block unable to be pulled away from the second block, each joint unit uneasy to return to the recess portion, and the distance between the first block and the second block uneasy to be changed. Thus, the first block and the second block of the stretchable members have two different states with different distances between the first block and the second block. Moreover, the distance between the first block and the second block is uneasy to be changed when the stretchable members are at the retracted state or the extended state for solving the detaching problem between the protecting device and the object. Furthermore, the stretchable members with multiple blocks and joint units can have more types of the extended state, which the different distances between the blocks of the stretchable members fulfills the needs for the objects with different sizes.

Claims

What is claimed is:

1. A protecting device for placing an object, comprising:

two connecting members; and

two stretchable members each attached between the two connecting members, the two stretchable members and the two connecting members enclosing together to form an accommodating space which is for placing the object, each of the stretchable members having a retracted state and a extended state, and each of the stretchable members comprising:

a first block comprising a first linking part;

a second block comprising two second linking parts separated with each other, and a first recess portion located between the two second linking parts; and

two first join units each comprising a first end and a second end that are opposite to each other, the two first ends attached with each other and attached to the first linking part, the two second ends separated with each other and attached to the two second linking parts respectively, twice a length between the first end and the second end of each first join unit being longer than a straight-line between the two second linking parts;

wherein, when the stretchable members are at the retracted state, at least part of each of the first joint unit is located inside the first recess portion, and when the stretchable members are at the extended state, each of the first joint unit is located outside the first recess portion.

2. The protecting device of claim 1, wherein the first block, the second block and the two first join unit are segmented from a main block, the main block has two side surfaces that are opposite to each other, two first cutting surfaces, two second cutting surfaces, two third cutting surfaces and two fourth cutting surfaces, the first join units are formed by each of the first cutting surface, each of the second cutting surface, each of the third cutting surfaces and each of the fourth cutting surfaces, wherein each of the first cutting surfaces and each of the fourth cutting surfaces extend from the side surfaces of the main block toward an interior of the main block, each of the second cutting surfaces and each of the third cutting surfaces keep a distance from the side surfaces of the main block, the third cutting surfaces connect with the first ends respectively, the fourth cutting surfaces connect with the second ends respectively, wherein when the stretchable members are at the retracted state, the first joint units and the first blocks are divided by the first cutting surfaces respectively, the fourth cutting surfaces and the first cutting surfaces connect with each other respectively, the first joint units and the second block are divided by the third cutting surfaces respectively, the two third cutting surfaces are connected with each other, and the second cutting surfaces connect with the third cutting surfaces respectively.

3. The protecting device of claim 2, wherein each of the first join units has a first angle formed by a connection of each of the second cutting surfaces and each of the third cutting surfaces respectively, the first angle is greater than or equal to 90 degrees and less than 150 degrees, each of the first join units has a second angle formed by a connection of each of the first cutting surfaces and each of the fourth cutting surfaces, the second angle is greater than or equal to 90 degrees and less than 150 degrees, wherein when the stretchable members are at the retracted state, the first cutting surfaces are paralleled to the second cutting surfaces, the third cutting surfaces are paralleled to the fourth cutting surfaces.

4. The protecting device of claim 2, wherein a width between the two side surfaces of the main block is X, when the stretchable members are at the retracted state, a distance between a connecting position of each of the first cutting surfaces and each of the side surfaces and a connecting position of each of the fourth cutting surfaces and each of the side surfaces is Y, a length of each of the first cutting surfaces is Z, a distance between each of the first cutting surfaces and each of the second cutting surfaces is M, a length of each of the second cutting surfaces is N, a length of each of the third cutting surfaces is P, a length of each of the fourth cutting surfaces is Q, a distance between each of an end of the second cutting surfaces and each of the fourth cutting surfaces is R, when the stretchable members are at the extended state, a distance between a connecting position of each of the first cutting surfaces and each of the side surfaces and a connecting position of each of the fourth cutting surfaces and each of the side surfaces is T, and the protecting device satisfies the following conditions:

X/2<Z<2X/3;

Q=Z/2;

P=Q/2;

Z/2<N<2Z/3;

M=Q/2;

Y<X/2;

R=Z−N; and

T=3Y/2.

5. The protecting device of claim 1, further comprising two covering members set on the two connecting members for covering the object.

6. The protecting device of claim 1, wherein the second block further comprise two third linking parts that are opposite to the two second linking parts and separated with each other, and a second recess portion locates between the two third linking parts, each of the stretchable members further comprising:

a third block comprising a fourth linking part; and

two second joint units each comprising a third end and a fourth end that are opposite to each other, the two third ends separated with each other and attached to the two third linking parts respectively, the two fourth ends attached with each other and attached to the fourth linking parts, twice a length between the third end and the fourth end of each second joint unit being longer than a straight-line distance between the two third linking parts;

wherein, when the stretchable members are at the retracted state, at least part of each of the second joint units is located inside the second recess portion, and when the stretchable members are at the extended state, each of the second joint units is located outside the second recess portion.

7. A stretchable member having a refracted state and a extended state comprising:

a first block comprising a first linking part;

a second block comprising two second linking parts separated with each other, and a recess portion locating between the two second linking parts; and

two join units each comprising a first end and a second end that are opposite to each other, the two first ends attached with each other and attached to the first linking part, the two second ends separated with each other and attached to the two second linking parts respectively, twice a length between the first end and the second end of each of the joint units being longer than a straight-line between the two second linking parts;

wherein, when the stretchable member is at the retracted state, at least part of each of the joint units is located inside the recess portion, and when the stretchable member is at the extended state, each of the joint units is located outside the recess portion.

8. The stretchable member of claim 7, wherein the first block, the second block and the two join units are segmented from a main block, the main block has two side faces that are opposite to each other, two first cutting surfaces, two second cutting surfaces, two third cutting surfaces and two fourth cutting surfaces, the joint units are formed by each of the first cutting surfaces, each of the second cutting surfaces, each of the third cutting surfaces and each of the fourth cutting surfaces, wherein, each of the first cutting surfaces and each of the fourth cutting surfaces extend from the side surfaces of the main block toward an interior of the main block, each of the second cutting surfaces and each of the third cutting surfaces keep a distance from the side surfaces of the main block, the third cutting surfaces connect with the first ends respectively, the fourth cutting surfaces connect with the second ends respectively; wherein when the stretchable member is at the retracted state, the joint units and the first blocks are divided by the first cutting surface respectively, the fourth cutting surfaces and the first cutting surfaces connect with each other respectively, the joint units and the second blocks are divided by the second cutting surfaces and the third cutting surfaces respectively, the two third cutting surfaces are connected with each other, and the second cutting surfaces connect with the third cutting surfaces respectively.

9. The stretchable member of claim 8, wherein each of the join units have a first angle formed by a connection of each of the second cutting surfaces and each of the third cutting surfaces, the first angle is greater than or equal to 90 degrees and less than 150 degrees, each of the join units have a second angle formed by the connection of each of the first cutting surfaces and each of the fourth cutting surfaces, the second angle is greater than or equal to 90 degrees and less than 150 degrees; wherein when the stretchable is at the retracted state, the first cutting surfaces are parallel to the second cutting surfaces, the third cutting surfaces are parallel to the fourth cutting surfaces.

10. The stretchable member of claim 8, wherein a width between the two side surfaces of the main block is X; when the stretchable member is at the retracted state, a distance between a connecting position of each of the first cutting surfaces and each of the side surfaces and a connecting position of each of the fourth cutting surfaces and each of the side surfaces is Y, a length of each of the first cutting surfaces is Z, a distance between each of the first cutting surfaces and each of the second cutting surfaces is M, a length of each of the second cutting surfaces is N, a length of each of the third cutting surfaces is P, a length of each of the fourth cutting surfaces is Q, a distance between each of the end of the second cutting surfaces and each of the fourth cutting surfaces is R; when the stretchable member is at the extended state, a distance between a connecting position of each of the first cutting surfaces and each of the side surfaces and a connecting position of each of the fourth cutting surfaces and each of the side surfaces is T, and the stretchable member satisfies the following conditions:

X/2<Z<2X/3;

Q=Z/2;

P=Q/2;

Z/2<N<2Z/3;

M=Q/2;

Y<X/2;

R=Z−N; and

T=3Y/2.