US20190320773A1

US20190320773A1 - Hair styling device

Info

Publication number: US20190320773A1
Application number: US16/390,056
Authority: US
Inventors: Stephanie Chang
Original assignee: Individual
Current assignee: Individual
Priority date: 2018-04-23
Filing date: 2019-04-22
Publication date: 2019-10-24
Also published as: CN110384323A; EP3560374A1; JP2019188148A; EP3560374B1

Abstract

A hair styling device includes a base; and a plurality of pins having respective first ends connected to a first side of the base, and spaced from each other. The base and the pins are produced from a single-layer flexible workpiece. Two of the plurality of pins are connected to each other at respective second ends opposite to the first ends, thereby forming a bistable mechanism that is capable of switching between concave-convex positions in response to an external force, and at least another two of the plurality of pins have free second ends opposite to the first ends, thereby forming a second branch layered from the first branch. The first branch is switched to a concave position relative to the second branch to create a space for receiving or releasing hair, and switched to a convex position relative to the second branch to close the space for securing hair.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a nonprovisional application claiming benefit from a prior-filed provisional application bearing a Ser. No. 62/661,593 and filed Apr. 23, 2018, the entity of which is incorporated herein for reference.

FIELD OF THE INVENTION

The present invention relates to a hair styling device, and more particularly to a hair styling device made of a flexible workpiece, and switching between a working state and a preparatory state with the state change of the flexible workpiece.

BACKGROUND OF THE INVENTION

A conventional hair clip, which is so-called as a snap clip, includes an upper metal piece 11 and a lower metal piece 12. The upper metal piece 11 consists of two metal pins connected together at one end, thereby forming a bistable mechanism that is capable of switching between concave-convex positions so as to render an open (preparatory) state and a closed (working or standby) state relative to the lower metal piece 12. When the upper metal piece 11 is switched to be the open position by forcing the upper metal piece 11 to become concave, as shown in FIG. 1A, a hair portion may enter the space between the upper metal piece 11 and lower metal piece 12. Then the metal piece 11 is forced to become convex, as shown in FIG. 1B, and close the space together with the lower metal piece 12 so as to clamp the hair portion inside. Afterwards, the upper metal piece 11 can be forced to open again for releasing the har portion.
Since the lower metal piece 12 of such a snap clip is implemented with a single metal strip, it is likely to slide off hair. Another conventional snap clip as shown in FIG. 1C is thus developed to ameliorate the unstable clamping problem. The snap clip includes an upper metal piece 11 similar to that shown in FIG. 1A, and a widened lower metal piece 13. The widened lower metal piece 13 is made hollow for reducing weight to minimize the gravity effect on sliding off hair. Even so, the clamping force of such a snap clip is still insufficient for stabilizing the clip on hair.
U.S. Pat. No. 7,373,940 discloses a snap clip as shown in FIG. 2A and FIG. 2B, which includes an upper metal piece 21, a lower metal piece 22, and a living hinge 23 between the upper metal piece 21 and the lower metal piece 22. Likewise, the upper metal piece 21 consists of two metal pins connected together at one end, thereby forming a bistable mechanism that is capable of switching between concave-convex positions so as to render an open (preparatory) state and a closed (working or standby) state relative to the lower metal piece 22. The lower metal piece 22 is formed under the upper metal piece 21 and has enhanced clamping force as more metal strips are involved for clamping hair. In addition, as the three metal strips are separate at the open end and have gaps in between, hair may enter the gaps and be hindered from relative movement to the metal strips due to interaction with the metal strips. Such a snap clip, however, suffers from the gravity effect since the snap clip is formed with a larger workpiece to be folded at a position of the living hinge 23 to define the upper metal piece 21 and the lower metal piece 22. The larger workpiece means a higher cost, and the folding operation means an additional procedure requiring aligning precision. Such a snap clip further suffers from an inherent gap between the upper metal piece 21 and the lower metal piece 22 as a result of folding the workpiece. The gap would adversely affect the clamping tightness. Moreover, the flexibility of the living hinge might adversely affect the bistable switching performance.

SUMMARY OF THE INVENTION

Therefore, there is a need to design a hair styling device, which has an improved clamping performance.
According to the present invention, a hair styling device includes a base; and a plurality of pins having respective first ends connected to a first side of the base, and spaced from each other. The base and the plurality of pins are produced from a single-layer flexible workpiece. At least two of the plurality of pins are connected to each other at respective second ends opposite to the first ends, thereby forming a bistable mechanism that is capable of switching between concave-convex positions in response to an external force, and at least another two of the plurality of pins have free second ends opposite to the first ends, thereby forming a second branch layered from the first branch. The first branch is switched to a concave position relative to the second branch to create a space for receiving or releasing hair, and switched to a convex position relative to the second branch to close the space for securing hair.
The pins forming the second branch may be all disposed between the pins forming the first branch. Alternatively, some of the pins forming the second branch are disposed between the pins forming the first branch, and the others are disposed outside the pins forming the first branch.
Shapes of the pins forming the second branch may be selected from lines, curves, waves, or a combination thereof, or any other suitable shape.
In an embodiment, adjacent two of the pins forming the second branch have respective lateral extensive structures protruding toward each other, and the lateral extensive structures are deformable to retain a resilient force when compressed by hair entering the space between the first branch and the second branch, thereby further securing hair in the hair styling device. Preferably, the lateral extensive structures are thinner than the pins where they are connected, and have conformable shapes to each other.
In an embodiment, the hair styling device further comprises mini-posts protruding from a specified surface of the pins forming the second branch and/or mini-posts protruding from a specified surface of the pins forming the first branch. Preferably, the specified surface of the pins forming the second branch is the surface facing the first branch, and the specified surface of the pins forming the first branch is the surface facing the second branch.
The single-layer flexible workpiece for producing a hair styling device according to the present invention is made of metal, plastic or paper.
The present invention also provides a method for producing a hair styling device as described above. The method comprises providing a metal sheet; stamping the metal sheet to obtain the single-layer flexible workpiece defining with the base and the plurality of pins; and connecting the at least two pins for forming the first branch.
The present invention further provides a method for producing a hair styling device as described above. The method comprises: providing an injection-molded plastic sheet as the single-layer flexible workpiece defining with the base and the plurality of pins; and connecting the at least two pins for forming the first branch.
The present invention further provides a method for producing a hair styling device as described above. The method comprises: providing a 3D printed material sheet as the single-layer flexible workpiece defining with the base and the plurality of pin; and connecting the at least two pins for forming the first branch.

BRIEF DESCRIPTION OF THE DRAWINGS

The above contents of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which:

FIGS. 1A and 1B are schematic diagrams illustrating two operational states of a conventional hair styling device;

FIG. 1C is a schematic diagram illustrating another conventional hair styling device;

FIGS. 2A and 2B are schematic diagrams illustrating two operational states of still another hair styling device;

FIG. 3A is a schematic top view of a workpiece for forming a hair styling device according to an embodiment of the present invention;

FIG. 3B is a schematic top view of the hair styling device produced from the workpiece of FIG. 3A;

FIGS. 3C and 3D are schematic side views illustrating two operational states of the hair styling device of FIG. 3B;

FIGS. 4A-4D are schematic top views illustrating variations of pins of hair styling devices according to the present invention;

FIG. 5A is a schematic top view of a workpiece for forming a hair styling device according to another embodiment of the present invention;

FIG. 5B is a schematic top view of the hair styling device produced from the workpiece of FIG. 5A;

FIG. 6A is a schematic top view of a workpiece for forming a hair styling device according to an embodiment of the present invention;

FIG. 6B is a schematic top view of the hair styling device produced from the workpiece of FIG. 6A;

FIG. 7A is a schematic top view of a workpiece for forming a hair styling device according to an embodiment of the present invention;

FIG. 7B is a schematic top view of the hair styling device produced from the workpiece of FIG. 7A;

FIGS. 7C and 7D are schematic side views illustrating two operational states of an example modified from the hair styling device of FIG. 7B;

FIGS. 7E and 7F are schematic side views illustrating two operational states of another example modified from the hair styling device of FIG. 7B;

FIG. 8A is a schematic top view of a workpiece for forming a hair styling device according to an embodiment of the present invention;

FIG. 8B is a schematic top view of the hair styling device produced from the workpiece of FIG. 8A;

FIGS. 8C and 8D are schematic side views illustrating two operational states of the hair styling device of FIG. 8B;

FIG. 9 is a schematic diagram illustrating a hair styling device according to an embodiment of the present invention, which is produced from an injection-molded workpiece;

FIG. 10 is a schematic top view of a hair styling device according to an embodiment of the present invention, which is produced from an injection-molded workpiece; and

FIG. 11 is a schematic diagram illustrating a hair styling device according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention will now be described more specifically with reference to the following embodiments. It is to be noted that the following descriptions of preferred embodiments of this invention are presented herein for purpose of illustration and description only; it is not intended to be exhaustive or to be limited to the precise form disclosed.
FIGS. 3A and 3B schematically illustrate an embodiment of a hair styling device according to the present invention, wherein FIG. 3A schematically illustrates a workpiece and FIG. 3B schematically illustrates a hair styling device produced from the workpiece of FIG. 3A. The workpiece is a flexible material sheet, which is integrally formed and configured as a single layer. The term “flexible” material sheet used herein and hereinafter means the material sheet is deformable when being applied with a proper intensity of external force, and restorable to its original state when the external force is removed. The flexible material sheet also includes a sheet of relative rigid material, which is thin enough to be elastically deformable. The workpiece is defined with a base 31 and four pins 301, 302, 303 and 304 commonly coupled to the base 31. Respective ends 3010 and 3040 of the pins 301 and 304 are connected to define a first branch 310. The structure of the first branch 310 renders a bistable mechanism that is capable of switching between concave-convex positions in response to an external force. The pins 302 and 303 have free ends 3020 and 3030, extending in a direction substantially the same as the pins 301 and 304, and defining a second branch 320 layered from the first branch 310. The second branch 320, as a whole, is substantially flat, and does not involve any state change when the hair styling device is operated in different states. Accordingly, a hair styling device as shown in FIG. 3B can be produced. For example, the hair styling device may be used as a snap clip. In this embodiment, the pins 301-304 of the workpiece are spaced from each other, and the pins 302 and 303 forming the second branch 320 are disposed between the pines 301 and 304 forming the first branch 310. Furthermore, the length of the pins 302 and 303 are shorter than that of the pines 301 and 304. Therefore, when the hair styling device is produced as shown in FIG. 3B, the second branch 320 is completely surrounded by the first branch 310 in a top view, while the second branch 320 is in a different layer from the first branch 310 in a side elevational view.
The use of the hair styling device is briefly exemplified herein. First, force the first branch 310 to switch to a concave position, as illustrated in FIG. 3C, thereby creating an open space 312 together with the second branch 320. Insert the pins 302 and 303 into hair to have hair enter the hair styling device from the open space 312. Then force the first branch 310 to switch to a convex position, as illustrated in FIG. 3D, thereby closing the opening space 312 together with the second branch 320 for securing hair therein. For releasing hair, force the first branch 310 to switch to the concave position again.
In the embodiment illustrated in FIG. 3, the pins 301-304 are linear and flat. In other embodiments, one or more of the pins may be independently modified to have alternative configurations according to practical requirements. FIGS. 4A-4D schematically illustrate examples of variations of pins according to the present invention. For example, as shown in FIG. 4A, the pins 302 and 303 are curved. In the example shown in FIG. 4B, the pins 302 and 303 are made wavy in a direction normal to the plane of the second branch 320 and/or in a directional conformal to the plane of the second branch 320. This embodiment is advantageous in enhancing the frictional force with hair clamped therein and thus improving clamping performance. Referring to FIG. 4C and FIG. 4D, for further stabling the hair styling device in hair, a lateral extensive structure 321 may be provided at one or both sides of the pin. The lateral extensive structure 321 is advantageous in enlarging the interaction area with hair. It is to be noted that the term “lateral” extensive structure means the structure 321 extends from the pin 302 or 303 in a direction substantially conformal to the plane of the second branch 320. The lateral extensive structure 321 may extend a little upper or lower relative to the plane of the second branch 320 as long as the function of the lateral extensive structure 321 can be conducted. Preferably, the lateral extensive structure 321 is thinner than the pin that it is connected to. The thin and flexible feature of the lateral extensive structure provides an elastically deformable feature to the hair styling device so as to further secure the clamped hair.
FIGS. 5A and 5B schematically illustrate an embodiment of a hair styling device according to the present invention, wherein FIG. 5A schematically illustrates a workpiece and FIG. 5B schematically illustrates a hair styling device produced from the workpiece of FIG. 5A. The workpiece is a flexible material sheet, which is integrally formed and configured as a single layer. The workpiece is defined with a base 51 and six pins 501, 502, 503, 504, 505 and 506 commonly coupled to the base 51. Respective ends 5020 and 5050 of the pins 502 and 505 are connected to define a first branch 510. The structure of the first branch 510 renders a bistable mechanism that is capable of switching between concave-convex positions in response to an external force. The pins 501, 503, 504 and 506 have free ends 5010, 5030, 5040 and 5060, extending in a direction substantially the same as the pins 502 and 505, and defining a second branch 520 layered from the first branch 510. The second branch 520, as a whole, is substantially flat, and does not involve any state change when the hair styling device is operated in different states. Accordingly, a hair styling device as shown in FIG. 5B can be produced. For example, the hair styling device may be used as a snap clip. In this embodiment, the pins 501-506 of the workpiece are spaced from each other, the pins 503 and 504 forming the second branch 520 are disposed between the pines 501 and 505 forming the first branch 510, and the pins 501 and 506 forming the second branch 520 are disposed outside the pines 501 and 505 forming the first branch 510. Furthermore, the length of the pins 503 and 504 are shorter than that of the pines 502 and 505, while the length of the pins 501 and 506 are longer than that of the pines 502 and 505. Therefore, when the hair styling device is produced as shown in FIG. 5B, the second branch 520 is partially distributed inside and partially distributed outside the first branch 510 in a top view, while the second branch 520 is in a different layer from the first branch 510 in a side elevational view. It is to be noted that the number and length of the pins forming the second branch 520 in each of the embodiments described herein, hereinbefore and hereinafter may properly change depending on practical requirements. By simultaneously inserting the four pins 501, 503, 504 and 506 into hair, the hair styling device can be used in more stable way. Furthermore, a variety of modifications to the pins, e.g. those shown in FIG. 4, can be made for improved functions and/or decoration purposes.
FIGS. 6A and 6B schematically illustrate an embodiment of a hair styling device according to the present invention, wherein FIG. 6A schematically illustrates a workpiece and FIG. 6B schematically illustrates a hair styling device produced from the workpiece of FIG. 6A. The workpiece is a flexible material sheet, which is integrally formed and configured as a single layer. The workpiece is defined with a base 61 and nine pins 601, 602, 603, 604, 605, 606, 607, 608 and 609 commonly coupled to the base 61. Respective ends 6030 and 6070 of the pins 603 and 607 are connected to define a first branch 610. The structure of the first branch 610 renders a bistable mechanism that is capable of switching between concave-convex positions in response to an external force. The pins 601, 602, 604, 605, 606, 608 and 609 have free ends 6010, 6020, 6040, 6050, 6060, 6080 and 6090, extending in a direction substantially the same as the pins 603 and 607, and defining a second branch 620 layered from the first branch 610. The second branch 620, as a whole, is substantially flat, and does not involve any state change when the hair styling device is operated in different states. Accordingly, a hair styling device as shown in FIG. 6B can be produced. For example, the hair styling device may be used as a snap clip. In this embodiment, the pins 601-609 of the workpiece are spaced from each other, the pins 604, 605 and 606 forming the second branch 620 are disposed between the pines 603 and 607 forming the first branch 610, and the pins 601, 602, 608 and 609 forming the second branch 620 are disposed outside the pines 603 and 607 forming the first branch 610. Therefore, when the hair styling device is produced as shown in FIG. 6B, the second branch 620 is partially distributed inside and partially distributed outside the first branch 610 in a top view, while the second branch 620 is in a different layer from the first branch 610 in a side elevational view. By simultaneously inserting the seven pins 601, 602, 604, 605, 606, 608 and 609 into hair, the hair styling device can be used in more stable way, and function like a comb clip. Furthermore, a variety of modifications to the pins, e.g. those shown in FIG. 4, can be made for improved functions and/or decoration purposes. The hair styling device in this embodiment further includes lateral extensive structures 621. The lateral extensive structures 621 extending from a pair of adjacent pins extend into a gap between the adjacent pins. The lateral extensive structures are thinner than the pins where they are connected, and have conformable shapes to each other. The lateral extensive structures 621 are deformable to retain a resilient force when compressed by hair entering the space between the first branch 610 and the second branch 620, thereby further securing hair in the hair styling device.
FIGS. 7A and 7B schematically illustrate an embodiment of a hair styling device according to the present invention, wherein FIG. 7A schematically illustrates a workpiece and FIG. 7B schematically illustrates a hair styling device produced from the workpiece of FIG. 7A. The workpiece is a flexible material sheet, which is integrally formed and configured as a single layer. The workpiece is defined with a base 71 and seven pins 701, 702, 703, 704, 705, 706, 707, 708 and 709 commonly coupled to the base 71. Respective ends 7020 and 7060 of the pins 702 and 706 are connected to define a first branch 710. The structure of the first branch 710 renders a bistable mechanism that is capable of switching between concave-convex positions in response to an external force. The pins 701, 703, 704, 705 and 707 have free ends 7010, 7030, 7040, 7050 and 7070, extending in a direction substantially the same as the pins 702 and 706, and defining a second branch 720 layered from the first branch 710. In this embodiment, Respective ends 7030 and 7050 of the pins 703 and 705 are connected as a composite pin of the second branch 710, which may be considered to have a free end as a whole. The structure of the composite pin renders a bistable mechanism that is capable of switching between concave-convex positions in response to an external force. Accordingly, a hair styling device as shown in FIG. 7B can be produced. For example, the hair styling device may be used as a snap clip. In this embodiment, the pins 701-707 of the workpiece are spaced from each other, the pins 703, 704 and 705 forming the second branch 720 are disposed between the pines 702 and 706 forming the first branch 710, and the pins 701 and 707 forming the second branch 720 are disposed outside the pines 702 and 706 forming the first branch 710. Therefore, when the hair styling device is produced as shown in FIG. 7B, the second branch 720 is partially distributed inside and partially distributed outside the first branch 710 in a top view, while the second branch 720 is in a different layer from the first branch 710 in a side elevational view. Furthermore, the composite pin is further layered from the other part of the second branch 720. When in use, the pins 710, 704 and 707 of the second branch is first inserted into hair. Then the pins 703 and 705 are forced to switch to a convex position to close and clamp hair together with the pins 710, 704 and 707. Afterwards, more hair may be put inside the open space between the pins 702 and 706 forming the first branch 710 and the pins 701, 703, 704, 705 and 707 forming the second branch 720, and the first branch 710 is forced to switch to a convex position to close the open space, thereby securing more hair thereinside.
The configurations of the entire hair styling device may vary with the distribution of lengths of the pins 703, 704 and 705. As shown in FIGS. 7C and 7D, which schematically illustrate an open state, e.g. a preparatory state, and a closed sate, e.g. a working state, the pins 702 and 706 forming the first branch 710 are longer than the pins 703 and 705 forming the composite pin of the second branch 720, which are further longer than the pins 701, 704 and 707 forming the other part of the second branch 720. Alternatively, as shown in FIGS. 7E and 7F, which schematically illustrate an open state, e.g. a preparatory state, and a closed sate, e.g. a working state, the pins 702 and 706 forming the first branch 710 are shorter than the pins 703 and 705 forming the composite pin of the second branch 720, which are longer than the pins 701, 704 and 707 forming the other part of the second branch 720. It is to be noted that the number and positions of pins in the second branch to be configured as a composite pin may vary with practical requirements, and the number and positions of composite pins may also vary with practical requirements.
FIGS. 8A and 8B schematically illustrate an embodiment of a hair styling device according to the present invention, wherein FIG. 8A schematically illustrates a workpiece and FIG. 8B schematically illustrates a hair styling device produced from the workpiece of FIG. 8A. The workpiece and the resulting hair styling device are similar to those shown in FIGS. 3A and 3B, except that there are mini-posts, e.g. teeth or bumps, disposed on surfaces of selected pins, forming an auxiliary structure 370. In this embodiment, the mini-posts extend from lateral surfaces of the pins as the auxiliary structure 370 is integrally formed with the workpiece. Of course, the mini-posts may be provided in alternative ways such as adhesion. By folding the mini-posts of the workpiece toward the space wherein hair is accommodated, a hair styling device having a structure as shown in FIG. 8B, and switchable between two states as shown in FIGS. 8C and 8D can be produced. The auxiliary structure 370 is advantageous in grasping hair. It is understood that any of the previously described embodiments of hair styling device may be provided with the auxiliary structure 370, and it is not intended to redundantly describe the details.
The workpiece used in the above-described embodiments and other embodiments modified from those embodiments according to the present invention may be formed of any proper flexible material and produced in a variety of ways. The materials, for example, include metal, plastic, paper, bamboo or any other relative rigid material with small thickness. When metal is used, a metal sheet is processed into a single-layer workpiece defined with a base and a plurality of pins and optional lateral extensive structure and/or auxiliary structure by way of stamping, and then associated pins are connected to form a hair styling device. Alternatively, the single-layer workpiece defined with a base and a plurality of pins and optional lateral extensive structure and/or auxiliary structure may also be produced by way of other techniques such as injection molding of plastic or three-dimensional (3D) printing of proper material. Particularly when the size of pins, gap between pins, extensive structure from pins, and/or auxiliary structures are small, injection molding or three-dimensional (3D) printing might be a better solution than stamping. For example, when producing a hair styling device as illustrated in FIG. 9, it is preferred to use injection molding to form a workpiece defined with a base 91, a first branch 910, a second branch 920 and an auxiliary structure 970 since the mini-posts 970 can be integrally formed, i.e. directly produced, with the other parts of the workpiece.
As long as the principles and purposes of the present invention can be achieved, the shapes, sizes and positions exemplified in different embodiments may be modified and combined according to practical requirements. For example, a hair styling device as illustrated in FIG. 10 includes various features of the above-described embodiments.
Please further refer to FIG. 11. The embodiment illustrated in FIG. 11 is similar to that shown in FIG. 3B except that an auxiliary structure 350 is provided. The auxiliary structure 350 includes three pins 311, 312 and 313 extending from another side of the base 31, opposite to the other pins 310-304. The pins 311, 312 and 313 may be integrally formed with the single-layer workpiece defined with the base 31 and the pins 301-304, and disposed under the second branch 320 by folding the workpiece from the base 31. When in use, the auxiliary structure 350 and the second branch 320 disposed in different layers are both inserted into hair, and then the first branch 310 is forced to switch to the convex position to clamp hair together with the second branch 320 and auxiliary structure 350. Since there are two layers of hair clamped inside the hair styling device, better clamping performance can be achieved, particularly for thick hair. The pins of the auxiliary structure 350 may overlap or stagger from the pins of the second branch 320. An overlapping configuration facilitates physical clamping between pins, while a staggering configuration exhibits slide-hindering capability.
In view of the foregoing, a hair styling device according to the present invention is cost-effective, laboring-effective, light and stable for use.
While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.

Claims

What is claimed is:

1. A hair styling device, comprising:

a base; and

a plurality of pins having respective first ends connected to a first side of the base, and spaced from each other,

wherein the base and the plurality of pins are produced from a single-layer flexible workpiece,

at least two of the plurality of pins are connected to each other at respective second ends opposite to the first ends, thereby forming a bistable mechanism that is capable of switching between concave-convex positions in response to an external force, and at least another two of the plurality of pins have free second ends opposite to the first ends, thereby forming a second branch layered from the first branch, and

the first branch is switched to a concave position relative to the second branch to create a space for receiving or releasing hair, and switched to a convex position relative to the second branch to close the space for securing hair.

2. The hair styling device according to claim 1, wherein all the pins forming the second branch are disposed between the pins forming the first branch.

3. The hair styling device according to claim 1, wherein the pins forming the second branch are not all disposed between the pins forming the first branch.

4. The hair styling device according to claim 1, wherein at least one of the pins forming the second branch is a composite pin formed by connecting two of the plurality of pins at respective second ends opposite to the first ends, thereby forming a bistable mechanism that is capable of switching between concave-convex positions in response to an external force.

5. The hair styling device according to claim 1, wherein shapes of the pins forming the second branch are selected from a group consisting of lines, curves, waves and a combination thereof.

6. The hair styling device according to claim 1, wherein adjacent two of the pins forming the second branch have respective lateral extensive structures protruding toward each other, and the lateral extensive structures are deformable to retain a resilient force when compressed by hair entering the space between the first branch and the second branch, thereby further securing hair in the hair styling device.

7. The hair styling device according to claim 6, wherein the lateral extensive structures are thinner than the pins connected thereto, and have conformable shapes to each other.

8. The hair styling device according to claim 6, wherein lateral extensive structures are produced from the single-layer flexible workpiece together with the base and the plurality of pins.

9. The hair styling device according to claim 1, further comprising mini-posts protruding from a specified surface of the pins forming the second branch.

10. The hair styling device according to claim 9, further comprising mini-posts protruding from a specified surface of the pins forming the first branch.

11. The hair styling device according to claim 10, wherein the specified surface of the pins forming the second branch is the surface facing the first branch, and the specified surface of the pins forming the first branch is the surface facing the second branch.

12. The hair styling device according to claim 10, wherein the mini-posts protruding from the specified surface of the pins forming the first branch are and the mini-posts protruding from the specified surface of the pins forming the second branch are produced from the single-layer flexible workpiece together with the base and the plurality of pins.

13. The hair styling device according to claim 1, further comprising an auxiliary structure connected to a second side of the base opposite to the first side, and disposed at a side of the second branch opposite to the first branch.

14. The hair styling device according to claim 1, wherein the single-layer flexible workpiece is made of metal, plastic or paper.

15. A method for producing a hair styling device as recited in claim 1, comprising:

providing a metal sheet;

stamping the metal sheet to obtain the single-layer flexible workpiece defining with the base and the plurality of pins; and

connecting the at least two pins for forming the first branch.

16. A method for producing a hair styling device as recited in claim 1, comprising:

providing an injection-molded plastic sheet as the single-layer flexible workpiece defining with the base and the plurality of pins; and

connecting the at least two pins for forming the first branch.

17. A method for producing a hair styling device as recited in claim 1, comprising:

providing a 3D printed material sheet as the single-layer flexible workpiece defining with the base and the plurality of pins; and

connecting the at least two pins for forming the first branch.