CN113851347A

CN113851347A - Tact switch and wiring method thereof

Info

Publication number: CN113851347A
Application number: CN202111167984.9A
Authority: CN
Inventors: 卢建昆; 羊建伟
Original assignee: Dongguan Linhong Technology Co ltd
Current assignee: Dongguan Linhong Technology Co ltd
Priority date: 2021-10-08
Filing date: 2021-10-08
Publication date: 2021-12-28

Abstract

The invention relates to a light-touch switch and a wiring method thereof, wherein a protruding part is arranged between a first fixed contact and a second fixed contact on the inner bottom surface of a switch box, and the second fixed contact and a third fixed contact which are kept in contact under a normal state are disconnected after an elastic sheet is contacted with the protruding part through pressing of a driving body on the elastic sheet, so that the third fixed contact is connected with the first fixed contact through the elastic sheet, and single-pole double-throw and/or single-pole single-throw can be realized through different wiring modes.

Description

Tact switch and wiring method thereof

Technical Field

The invention relates to the technical field of tact switches, in particular to a tact switch and a wiring method thereof.

Background

The tact switch has a small size and a light weight, and thus is widely used in household appliances, automobiles, and the like. The tact switch is an electronic switch, belonging to the electronic components. The switch consists of an insert, a base, an elastic sheet, a button and a cover plate, when the switch is used, the switch can be switched on by lightly pressing the switch button, and when a hand is released, the switch is switched off, and the internal structure of the switch is switched on and off by the elastic movement of the metal elastic sheet under the stress. The tact switch may be of a single-pole double-throw type, a single-pole single-throw type, or the like, depending on the structure.

Chinese patent application publication No. CN 1444243A discloses a push switch in which a first movable contact composed of an annular portion and a projection projecting in the same width as the annular portion is opposed to a peripheral fixed contact and a central fixed contact on the bottom surface of a switch case, and the annular portion is spaced from the peripheral fixed contact by a predetermined distance. This prior art provides a two-stage operation push switch which occupies a small space due to its narrow size and can easily set the operation force of each switch. The prior art has the following defects: the function of single-pole double-throw can be realized through two-stage action by arranging a complex combined spring plate structure in a narrow space.

The conventional techniques such as those disclosed in publication nos. CN205810632U and CN205004218U have a structure that can realize only a single-pole single-throw function, and cannot realize a single-pole double-throw function based on the structure.

Therefore, there is a need for an improvement on the basis of the existing tact switch, which realizes single-pole double-throw and/or single-pole single-throw with a simple structure in a narrow space, and which has certain improvements in the difficulty of mounting and dismounting the structure and the structural reliability.

Disclosure of Invention

The invention provides a tact switch and a wiring method thereof, aiming at the defects of the prior art.

In a first aspect, an embodiment of the present invention provides a tact switch, which includes: a switch box with an opening on the upper surface; a first fixed contact formed at the center on the inner bottom surface of the switch case; a second fixed contact and a third fixed contact formed on the inner bottom surface of the switch box and clamping the first fixed contact; a first connection terminal, a second connection terminal and a third connection terminal electrically connected to the first fixed contact, the second fixed contact and the third fixed contact, respectively, at an outer periphery of the switch case; a protrusion part formed on the inner bottom surface of the switch box and located between the first fixed contact and the second fixed contact; the spring piece is in contact with the second fixed contact and the third fixed contact under the action of non-external force in the switch box, and is provided with a first contact in contact with the second fixed contact and a second contact in contact with the third fixed contact; and a driving body having a pressing spring plate, the driving body being disposed above the spring plate so as to be movable up and down; the driving body descends to press the elastic sheet after being acted by external force, the center of the elastic sheet is pressed to be locally deformed to be in contact with the first fixed contact, and the elastic sheet is in contact with the protruding portion in the local deformation process and takes the protruding portion as a supporting point to lift the first contact so as to release the contact state of the first contact and the second fixed contact.

In some embodiments, the first fixing contact and the first connection terminal are a first metal piece integrally formed, the second fixing contact and the second connection terminal are a second metal piece integrally formed, and the third fixing contact and the third connection terminal are a third metal piece integrally formed.

In some embodiments, a fourth connecting terminal is disposed on the outer periphery of the switch box, and the fourth connecting terminal and the first metal part are integrally formed fourth metal parts.

In some embodiments, the second metal piece, the third metal piece and the fourth metal piece are integrally injection-molded with the switch box.

In some embodiments, the elastic sheet has a central portion located at the center and an annular portion located at the periphery, the central portion is higher than the annular portion, and the central portion and the annular portion are connected through the conical ring portion.

In some of the embodiments, the protrusion is higher than the first fixed contact, the second fixed contact, and the third fixed contact, and the first fixed contact is lower than the second fixed contact and the third fixed contact.

In some embodiments, the driving body is connected to a positioning portion at its periphery by a bridging portion, the positioning portion is mounted on an end surface of the opening of the switch box and is vertically fixed by buckling the cover plate with the switch box, the cover plate has a vertical extending portion, the extending portion has a fastening hole, and a protruding portion at the periphery of the positioning portion is fastened in the fastening hole to horizontally fix the positioning portion.

In a second aspect, an embodiment of the present invention provides a wiring method for a tact switch, where the tact switch as in the first aspect is used, including: one path of the load is electrically connected with the second connecting terminal, the other path of the load is electrically connected with the third connecting terminal, the other path of the load is electrically connected with the first connecting terminal, the load forms a first loop through the second connecting terminal, the elastic sheet and the third connecting terminal, the load forms a second loop through the third connecting terminal, the elastic sheet and the first connecting terminal, and the first loop and the second loop are switched by pressing the elastic sheet.

In a third aspect, an embodiment of the present invention provides a wiring method for a tact switch, where the tact switch as in the first aspect is used, including: one path of the load is electrically connected with the second connecting terminal, the other path of the load is electrically connected with the third connecting terminal, the load forms a third loop and is normally closed through the second connecting terminal, the elastic sheet and the third connecting terminal, after the elastic sheet is pressed, the second connecting terminal and the third connecting terminal are disconnected, the load is electrically connected with the first connecting terminal through the third connecting terminal and the elastic sheet, and the third loop is disconnected.

In a fourth aspect, an embodiment of the present invention provides a wiring method for a tact switch, where the tact switch as in the first aspect is used, including: one path of the load is electrically connected with the first connecting terminal, the other path of the load is electrically connected with the third connecting terminal, the load forms a fourth loop through the first connecting terminal, the elastic sheet and the third connecting terminal and is normally open, after the elastic sheet is pressed, the first connecting terminal is connected with the third connecting terminal, and the fourth loop is closed.

Compared with the related art, the tact switch provided by the embodiment of the invention has the advantages that the protruding part is arranged between the first fixed contact and the second fixed contact on the inner bottom surface of the switch box, the second fixed contact and the third fixed contact which are kept in contact under a normal state are disconnected after the elastic piece is contacted with the protruding part through the pressing of the driving body on the elastic piece, the third fixed contact is connected with the first fixed contact through the elastic piece, and the single-pole double-throw and/or the single-pole single-throw can be realized through different wiring modes.

The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below to provide a more thorough understanding of the invention.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

fig. 1 is an assembled perspective view of a tact switch according to an embodiment of the present invention.

Fig. 2 is an exploded structural view of the tact switch according to the embodiment of the present invention.

Fig. 3 is a sectional structure view of the tact switch according to the embodiment of the present invention.

Fig. 4 is a structural diagram of a second metal part, a third metal part, and a fourth metal part of the tact switch according to the embodiment of the present invention.

Fig. 5 is a schematic diagram of a wiring method of the tact switch according to embodiment 1 of the present invention.

Fig. 6 is a schematic diagram of a wiring method of the tact switch according to embodiment 2 of the present invention.

Fig. 7 is a schematic diagram of a wiring method of the tact switch according to embodiment 3 of the present invention.

In the figure, 1, a switch box; 2. a spring plate; 3. a drive body; 4. a cover plate; 5. a second metal piece; 6. a third metal piece; 7. a fourth metal piece; 8. a first fixed contact; 9. a second fixed contact; 10. a third fixed contact; 11. a first connection terminal; 12. a second connection terminal; 13. a third connection terminal; 14. a fourth connection terminal; 15. a protrusion portion; 16. a first plateau; 17. a second plateau; 18. a central portion; 19. an annular portion; 20. a conical ring portion; 21. a first contact; 22. a second contact; 23. a bridge portion; 24. a positioning part; 25. a protrusion; 26. an end face; 27. an extension portion; 28. a clamping hole; 29. a positioning column; 30. a load; 31. a first circuit; 32. a second loop; 33. a third circuit; 34. a fourth loop; 35. a convex edge; 36. a micro-protrusion.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described and illustrated below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments provided by the present invention, belong to the protection scope of the present invention. Moreover, it should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another.

Reference in the specification to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the invention. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one of ordinary skill in the art that the described embodiments of the present invention can be combined with other embodiments without conflict.

Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The use of the terms "a" and "an" and "the" and similar referents in the context of describing the invention are not to be construed as limiting in number, and may be construed to cover both the singular and the plural. The present invention relates to the terms "comprises," "comprising," "includes," "including," "has," "having" and any variations thereof, which are intended to cover non-exclusive inclusions; for example, a process, method, system, article, or apparatus that comprises a list of steps or modules (elements) is not limited to the listed steps or elements, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus. The terms "connected," "coupled," and the like in the description of the invention are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The term "plurality" as used herein means two or more. "and/or" describes an association relationship of associated objects, meaning that three relationships may exist, for example, "A and/or B" may mean: a exists alone, A and B exist simultaneously, and B exists alone. The terms "first," "second," "third," and the like in reference to the present invention are used merely to distinguish between similar objects and not necessarily to represent a particular ordering for the objects.

As shown in fig. 1-4, a tact switch according to an embodiment of the present invention mainly includes a switch box 1, an elastic piece 2, a driving body 3, and a cover plate 4, wherein the switch box 1 is made of an insulating material and integrally injection-molded with a second metal piece 5, a third metal piece 6, and a fourth metal piece 7 as conductive media, the elastic piece 2 is made of a metal material which is also used as a conductive medium, the driving body 3 is made of an insulating material, and the cover plate 4 can be configured to be made of a metal material or a plastic material as required.

As shown in fig. 2 to 3, the switch box 1 of the present embodiment has a first fixed contact 8, a second fixed contact 9, and a third fixed contact 10 on an inner bottom surface thereof, a first connection terminal 11, a second connection terminal 12, a third connection terminal 13, and a fourth connection terminal 14 on an outer periphery of the switch box 1, a second metal member 5 is integrally formed by the second fixed contact 9 and the second connection terminal 12, a third metal member 6 is integrally formed by the third fixed contact 10 and the third connection terminal 13, and a fourth metal member 7 is integrally formed by the first fixed contact 8, the first connection terminal 11, and the fourth connection terminal 14. A protrusion 15 is disposed on the inner bottom surface of the switch case 1 between the first fixed contact 8 and the second fixed contact 9, the protrusion 15 is higher than the first fixed contact 8, the second fixed contact 9, and the third fixed contact 10, and the first fixed contact 8 is lower than the second fixed contact 9 and the third fixed contact 10. A first step 16 and a second step 17 are arranged on the inner bottom surface of the switch case 1, the first step 16 is located on one side of the line connecting the second fixed contact 9 and the third fixed contact 10, the second step 17 is located on the other side, and the first step 16 and the second step 17 are lower than the second fixed contact 9 and the third fixed contact 10. The first high platform 16, the second high platform 17, the second fixed contact 9 and the third fixed contact 10 are used for supporting the assembly of the elastic sheet 2, so that the offset range of the elastic sheet 2 after being pressed is not too large, and the transitional offset condition is avoided, and the stability and reliability of the switch are ensured.

As shown in fig. 2-3, the elastic sheet 2 of the present embodiment is a disk-shaped whole, and has a central portion 18 located at the center and an annular portion 19 located at the periphery, the central portion 18 is higher than the annular portion 19, and the central portion 18 and the annular portion 19 are connected by a conical ring portion 20. Under the normal state, the elastic sheet 2 is not acted by external force, the annular part 19 of the elastic sheet 2 keeps contact with the second fixed contact 9 and the third fixed contact 10, the annular part 19 is contacted with the second fixed contact 9 to form a first contact 21, and the annular part 19 is contacted with the third fixed contact 10 to form a second contact 22. Under the pressing of external force, the central portion 18 of the elastic sheet 2 is deformed by pressing, under the action of the conical ring portion 20, before the elastic sheet 2 is deformed by pressing and does not contact with the protruding portion 15, the first contact 21 and the second contact 22 of the annular portion 19 are still respectively kept in contact with the second fixed contact 9 and the third fixed contact 10, so that the second fixed contact 9 and the third fixed contact 10 are kept connected through the elastic sheet 2, after the elastic sheet 2 is deformed by pressing and contacts with the protruding portion 15, in the process that the central portion 18 of the elastic sheet 2 is continuously deformed by pressing, the annular portion 19 where the first contact 21 is located is tilted by taking the protruding portion 15 as a fulcrum, so that the first contact 21 is disconnected from the second fixed contact 9, namely the second fixed contact 9 is disconnected from the third fixed contact 10.

In addition, the annular part 19 of the spring plate 2 is configured to be in surface contact or line contact with the second fixed contact 9 and the third fixed contact 10, in this embodiment, a surface contact mode is adopted, a contact area is ensured, and the protrusion part 15 is located in a vertical projection range of the central part 18 on the inner bottom surface of the switch box 1. Compared with the first fixed contact 8, the protrusion 15 is closer to the second fixed contact 9, so that the central portion 18 has a larger deformation space, and the annular portion 19 of the spring plate 2 has a better tilting effect.

As shown in fig. 2 to 3, in the driving body 3 of the present embodiment, the positioning portion 24 is connected to the periphery of the driving body 3 through the bridge portion 23, and the positioning portion 24 has four symmetrical protrusions 25 on the periphery thereof, so that the position adjustment is not required when the driving body is assembled on the switch box 1, thereby improving the convenience of assembly. The driving body 3, the bridge portion 23 and the positioning portion 24 are all made of an integrally formed elastic material, such as an insulating material like silicon gel. The positioning portion 24 is bridged over an open end surface 26 of the switch case 1, and the positioning portion 24 is vertically fixed by engaging the cover plate 4 with the switch case 1. As shown in the drawings, the cover plate 4 of the present embodiment has a vertical extending portion 27, and the extending portion 27 has a fastening hole 28, the fastening hole 28 is also used as a fastening hole for fastening with the switch box 1, and the protrusion 25 at the periphery of the positioning portion 24 is fastened in the fastening hole 28 to horizontally fix the positioning portion 24. In the present embodiment, the driving body 3 is not completely fitted into the switch case 1, but is bridged on the opening end surface 26 of the switch case 1 by the positioning portion 24, and the difficulty of attachment and detachment is effectively reduced. The lower edge of the fastening hole 28 formed on the extension part 27 is recessed toward the outer wall of the switch box 1, and a micro-protrusion 36 is formed on the inner side, and the micro-protrusion 36 helps to enhance the fastening effect of the fastening hole on the outer wall of the switch box 1, thereby improving the structural reliability of the switch of the present invention.

In addition, a positioning column 29 is disposed on the outer bottom surface of the switch box 1, and the tact switch can be pre-positioned on the PCB board by inserting the positioning column 29 into a positioning hole on the PCB board when being assembled on the PCB board.

The end surface 26 of the opening of the switch box 1 is provided with an annular convex edge 35 which surrounds the opening and is higher than the end surface 26, the sealing performance between the positioning part 24 is enhanced through the arrangement of the convex edge 35, and the waterproof and dustproof performance of the switch is improved.

As shown in fig. 5, in embodiment 1 of the wiring method of the tact switch of the present invention, assuming a load 30, the load 30 may be a chip, a lamp, etc., one path of the load 30 is electrically connected to the second connection terminal 12, the other path is electrically connected to the third connection terminal 13, the other path is electrically connected to the first connection terminal 11, the load 30 forms a first loop 31 through the second connection terminal 12, the spring 2 and the third connection terminal 13, the load 30 forms a second loop 32 through the third connection terminal 13, the spring 2 and the first connection terminal 11, and the first loop 31 and the second loop 32 are switched by pressing the spring 2. Embodiment 1 realizes the single-pole double-throw function by switching the first circuit 31 and the second circuit 32.

As shown in fig. 6-7, on the basis of the same tact switch, different wiring methods are used to realize single-pole single-throw functions with different functions. Fig. 6 shows an embodiment 2 of the wiring method of the present invention, which specifically includes: one path of the load 30 is electrically connected with the second connecting terminal 12, the other path is electrically connected with the third connecting terminal 13, the load 30 forms a third loop 33 through the second connecting terminal 12, the elastic sheet 2 and the third connecting terminal 13 and is normally closed, after the elastic sheet 2 is pressed, the second connecting terminal 12 and the third connecting terminal 13 are disconnected, the load 30 is electrically connected with the first connecting terminal 11 through the third connecting terminal 13 and the elastic sheet 2, and the third loop 33 is disconnected. Fig. 7 shows an embodiment 3 of the wiring method of the present invention, which specifically includes: one path of the load 30 is electrically connected with the first connecting terminal 11, the other path is electrically connected with the third connecting terminal 13, the load 30 forms a fourth loop 34 through the first connecting terminal 11, the elastic sheet 2 and the third connecting terminal 13 and is normally open, after the elastic sheet 2 is pressed, the first connecting terminal 11 is connected with the third connecting terminal 13, and the fourth loop 34 is closed. In the

embodiments

2 and 3, the third circuit 33 and the fourth circuit 34 are controlled to be turned on and off by pressing the elastic sheet 2, that is, the function of single-pole single-throw is realized.

The working principle of the embodiment of the invention is as follows:

under normal state, the first fixed contact 8 is not contacted with the elastic sheet 2, and the second fixed contact 9 and the third fixed contact 10 form a passage through the elastic sheet 2; after external force is applied to the driving body 3 from top to bottom, the driving body 3 moves downwards in the switch box 1 by means of the positioning portion 24 and the bridge portion 23, in the process of moving downwards, the bottom surface of the driving body 3 extrudes the central portion 18 of the elastic sheet 2, the central portion 18 of the elastic sheet 2 deforms downwards after being extruded, in the continuous deformation process, the bottom surface of the elastic sheet 2 touches the protruding portion 15 on the inner bottom surface of the switch box 1, then the elastic sheet 2 uses the protruding portion 15 as a fulcrum to tilt the annular portion 19 of the elastic sheet 2, the first contact 21 of the tilted annular portion 19 is disconnected with the second fixed contact 9, then the second fixed contact 9 is disconnected with the third fixed contact 10, meanwhile, the central portion 18 of the elastic sheet 2 deforms to be in contact with the first fixed contact 8, and the first fixed contact 8 forms a passage with the third fixed contact 10 through the elastic sheet 2.

It should be understood by those skilled in the art that various features of the above-described embodiments can be combined in any combination, and for the sake of brevity, all possible combinations of features in the above-described embodiments are not described in detail, but rather, all combinations of features which are not inconsistent with each other should be construed as being within the scope of the present disclosure.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A tact switch, comprising:

a switch box (1) with an opening is arranged on the upper surface;

a first fixed contact (8) formed at the center on the inner bottom surface of the switch case (1);

a second fixed contact (9) and a third fixed contact (10) formed on the inner bottom surface of the switch box (1) and sandwiching the first fixed contact (8);

a first connection terminal (11), a second connection terminal (12), and a third connection terminal (13) that are electrically connected to the first fixed contact (8), the second fixed contact (9), and the third fixed contact (10), respectively, at the outer periphery of the switch case (1);

a protrusion (15) formed on the inner bottom surface of the switch case (1) and located between the first fixed contact (8) and the second fixed contact (9);

the elastic sheet (2) is arranged in the switch box (1) and keeps in contact with the second fixed contact (9) and the third fixed contact (10) under the action of non-external force, and the elastic sheet (2) is provided with a first contact (21) which keeps in contact with the second fixed contact (9) and a second contact (22) which keeps in contact with the third fixed contact (10); and

a driving body (3) for pressing the elastic sheet (2), wherein the driving body (3) is arranged above the elastic sheet (2) in a vertically movable manner;

the driving body (3) descends and presses the elastic sheet (2) after being acted by external force, the center of the elastic sheet (2) is pressed to be locally deformed and is in contact with the first fixed contact (8), and the elastic sheet (2) is in contact with the protruding portion (15) in the local deformation process and lifts the first contact (21) by taking the protruding portion (15) as a fulcrum so as to release the contact state of the first contact (21) and the second fixed contact (9).

2. A tact switch according to claim 1, characterized in that said first fixed contact (8) and said first connection terminal (11) are a first metal piece formed integrally, said second fixed contact (9) and said second connection terminal (12) are a second metal piece (5) formed integrally, and said third fixed contact (10) and said third connection terminal (13) are a third metal piece (6) formed integrally.

3. The tact switch according to claim 2, wherein a fourth connecting terminal (14) is disposed on an outer periphery of the switch case (1), and the fourth connecting terminal (14) and the first metal member are a fourth metal member (7) integrally molded.

4. A tact switch according to claim 3, characterized in that said second metal piece (5), third metal piece (6) and fourth metal piece (7) are injection molded integrally with said switch box (1).

5. A tact switch according to claim 1, characterized in that said elastic piece (2) has a central portion (18) located at the center and a peripheral annular portion (19), said central portion (18) being higher than said annular portion (19), said central portion (18) and annular portion (19) being joined by a conical ring portion (20).

6. A tact switch according to claim 5, characterized in that said protruding portion (15) is higher than said first fixed contact (8), second fixed contact (9) and third fixed contact (10), said first fixed contact (8) being lower than said second fixed contact (9) and third fixed contact (10).

7. The tact switch according to claim 1, wherein a positioning portion (24) is connected to the periphery of the driving body (3) through a bridge portion (23), the positioning portion (24) is erected on an end surface (26) of the opening of the switch box (1), and the positioning portion (24) is vertically fixed by buckling a cover plate (4) with the switch box (1), the cover plate (4) has a vertical extending portion (27), the extending portion (27) has a locking hole (28), and a protruding portion (25) on the periphery of the positioning portion (24) is locked in the locking hole (28) to horizontally fix the positioning portion (24).

8. A method of wiring a tact switch, characterized by using a tact switch according to any one of claims 1 to 7, comprising: all the way of load (30) with second connecting terminal (12) electricity is connected, all the way with third connecting terminal (13) electricity is connected, all the way with first connecting terminal (11) electricity is connected, load (30) constitute first return circuit (31) through second connecting terminal (12), shell fragment (2) and third connecting terminal (13), load (30) constitute second return circuit (32) through third connecting terminal (13), shell fragment (2) and first connecting terminal (11), through pressing shell fragment (2) switch first return circuit (31) and second return circuit (32).

9. A method of wiring a tact switch, characterized by using a tact switch according to any one of claims 1 to 7, comprising: all the way of load (30) with second connecting terminal (12) electricity is connected, all the way with third connecting terminal (13) electricity is connected, load (30) constitute third return circuit (33) and normally closed through second connecting terminal (12), shell fragment (2) and third connecting terminal (13), press behind shell fragment (2), second connecting terminal (12) and third connecting terminal (13) break off, load (30) are connected with first connecting terminal (11) electricity through third connecting terminal (13), shell fragment (2), third return circuit (33) disconnection.

10. A method of wiring a tact switch, characterized by using a tact switch according to any one of claims 1 to 7, comprising: load (30) all the way with first connecting terminal (11) electricity is connected, all the way with third connecting terminal (13) electricity is connected, load (30) constitute fourth return circuit (34) and normally open through first connecting terminal (11), shell fragment (2) and third connecting terminal (13), press shell fragment (2) back, first connecting terminal (11) and third connecting terminal (13) meet, fourth return circuit (34) are closed.