CN216353900U - Switch structure - Google Patents

Abstract

The present disclosure relates to a switch structure including a mounting bracket, a tact switch, a pressing assembly, and an inflection point mechanism. The light touch switch is arranged on the mounting frame, the pressing component is movably arranged on the mounting frame to press the light touch switch, the inflection point mechanism is connected with the pressing component, and the pressing component is sequentially provided with a first movement stage and a second movement stage in the process of pressing the light touch switch; in a first motion phase, the inflection mechanism applies a resistance force to the pressing assembly; in a second motion phase, the knee mechanism applies an assistance force to the pressing assembly. The switch structure has a paragraph sense in the pressing process, and the use experience of a user can be improved.

Description

Switch structure

Technical Field

The present disclosure relates to the field of switch technology, and more particularly, to a switch structure.

Background

The switches are widely used, and people often use the switch structures to control the opening and closing of electric appliances, lighting equipment and the like. However, the switch structure in the related art often has no sense of paragraph in the pressing process, the operation hand feeling is poor, and the use experience of the user on the switch structure is reduced.

SUMMERY OF THE UTILITY MODEL

In order to overcome the problems in the related art, the present disclosure provides a switch structure, which has a sense of paragraph in the pressing process, and can improve the user experience.

According to a first aspect of embodiments of the present disclosure, there is provided a switch structure, comprising: a mounting frame; the tact switch is arranged on the mounting rack; the pressing component is movably arranged on the mounting rack to press the tact switch; the inflection point mechanism is connected with the pressing component, and the pressing component is sequentially provided with a first motion stage and a second motion stage in the process of pressing the tact switch; in the first motion phase, the knee mechanism applies a resistance force to the pressing assembly; in the second motion phase, the knee mechanism applies an assistance force to the pressing assembly.

In some embodiments, the pressing assembly includes a pressing piece and a resetting piece;

the pressing piece is slidably arranged on the mounting frame along the pressing direction of the tact switch so as to press the tact switch; the resetting piece is used for driving the pressing piece to reset so as to release the pressing piece from pressing the tact switch; the pressing piece is connected with the inflection point mechanism, and the inflection point mechanism applies resistance to the pressing piece in the first motion stage; in the second movement phase, the knee mechanism applies an assistance force to the pressing piece.

In some embodiments, the pressing assembly includes a pressing piece, a restoring piece, and a pressing plate; the pressing piece is slidably arranged on the mounting frame along the pressing direction of the tact switch so as to press the tact switch; the pressing plate is rotatably arranged on the mounting frame, and in the rotating process of the pressing plate, the pressing plate can be abutted against the pressing piece and drive the pressing piece to slide; the pressing plate is connected with the inflection point mechanism, and the inflection point mechanism applies resistance to the pressing plate in the first motion stage; in the second motion phase, the inflection point mechanism applies an assisting force to the pressing plate; the resetting piece is used for driving the pressing piece and the pressing plate to reset.

In some embodiments, the knee mechanism includes a first rotating member, a second rotating member, and an elastic member; the first rotating part and the second rotating part are both rotatably arranged on the mounting frame, the pressing plate is connected with the first rotating part to drive the first rotating part to rotate, the first rotating part is connected with the second rotating part to drive the second rotating part to rotate, the elastic part is arranged on the first rotating part and is used for being connected with the second rotating part, and in the first motion stage, the deformation quantity of the elastic part under the rotation of the second rotating part is gradually increased and resistance is applied to the rotation of the second rotating part; in the second motion stage, the elastic element gradually restores the deformation amount and applies assistance to the rotation of the second rotating element.

In some embodiments, the first rotating member comprises a sleeve, the second rotating member comprises a stop plate, and the resilient member comprises a spring; one end of the sleeve is closed, the other end of the sleeve is open, the sleeve is rotatably arranged on the mounting frame around a first axis intersecting with the axis of the sleeve, the closed end of the sleeve is hinged with the pressing plate, and a groove is formed at the open end of the sleeve; the spring is arranged in the sleeve along a direction parallel to the axis of the sleeve; the baffle is rotatably arranged on the mounting frame around a second axis parallel to the first axis, and the baffle is inserted into the groove and is abutted against the spring.

In some embodiments, the first rotating member further includes a first driving rod and a first rotating shaft, the first rotating shaft is connected to an outer side wall of the sleeve along the direction of the first axis to be rotatably disposed on the mounting frame, and the first driving rod is disposed on the closed end of the sleeve; the pressing plate comprises a pressing plate body and a hinged part arranged on the inner side of the pressing plate body, and the first transmission rod is rotatably arranged on the hinged part; the second rotating part further comprises a second rotating shaft and a spring post, and the second rotating shaft is connected to the baffle along the direction of the second axis so as to be rotatably arranged on the mounting rack; the spring column is convexly arranged on one side of the baffle plate, which is used for abutting against the spring, so as to be inserted into the spring.

In some embodiments, the first rotating member is an integrally formed structure, and/or the second rotating member is an integrally formed structure.

In some embodiments, the mounting bracket is formed with a pressing groove extending along the pressing direction, and the tact switch is disposed on an inner bottom wall of the pressing groove; the pressing piece comprises a pressing cap and a protruding block, the pressing cap is slidably arranged in the pressing groove along the pressing direction, and the protruding block is arranged on the inner side of the pressing cap and used for abutting against the light touch switch.

In some embodiments, the reset member includes a reset spring, the reset spring is disposed in the pressing groove, and two ends of the reset spring are respectively used for abutting against the inner side of the pressing cap and the inner bottom wall of the pressing groove.

In some embodiments, the tact switches are provided in plurality, and the pressing member and the inflection point mechanism are each provided in plurality in one-to-one correspondence with the plurality of tact switches.

The technical scheme provided by the embodiment of the disclosure can have the following beneficial effects: by arranging the inflection point mechanism connected with the pressing component, a first movement stage and a second movement stage are sequentially provided in the process that a user presses the tact switch through the pressing component; in addition, in the first movement stage, the inflection point mechanism applies resistance to the pressing component, and in the second movement stage, the inflection point mechanism applies resistance to the pressing component.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and together with the description, serve to explain the principles of the disclosure.

FIG. 1 is a schematic perspective view of a switch structure according to an exemplary embodiment;

fig. 2 is a cross-sectional view of a switch structure shown according to an exemplary embodiment, wherein the pressing piece is not pressed by the pressing plate;

FIG. 3 is a cross-sectional view of a switch structure shown in accordance with an exemplary embodiment, wherein a press plate drives a press member to press a tact switch to an ON state;

FIG. 4 is a schematic diagram of a first rotating member of a switch configuration according to an exemplary embodiment;

fig. 5 is a schematic diagram of a second rotating member of a switch configuration according to an exemplary embodiment.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the exemplary embodiments below are not intended to represent all implementations consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.

As shown in fig. 1 to 5, the present disclosure provides a switch structure including a mounting bracket 1, a tact switch 2, a pressing member 3, and an inflection point mechanism 4. The tact switch 2 is arranged on the mounting frame 1, the pressing component 3 is movably arranged on the mounting frame 1 to press the tact switch 2, the inflection point mechanism 4 is connected with the pressing component 3, and the pressing component 3 sequentially has a first movement stage and a second movement stage in the process of pressing the tact switch 2; in a first movement phase, the inflection mechanism 4 applies a resistance force to the pressing assembly 3; in a second movement phase, the knee mechanism 4 applies an assistance force to the pressing assembly 3.

The tact switch 2 may be used to turn on or off the control circuit or may be electrically connected to the microprocessor to transmit an operation signal to the microprocessor.

In the technical scheme, by arranging the inflection point mechanism 4 connected with the pressing component 3, a first motion stage and a second motion stage are sequentially provided in the process that a user presses the tact switch 2 through the pressing component 3; in addition, in the first movement stage, the inflection point mechanism 4 applies resistance to the pressing component 3, and in the second movement stage, the inflection point mechanism 4 applies resistance to the pressing component 3, so that a user who performs pressing operation receives resistance first and then assistance, obvious paragraph feeling exists, and the pressing experience effect of the user is good.

In one embodiment, the pressing assembly 3 comprises a pressing member 31 and a resetting member 32; the pressing piece 31 is slidably arranged on the mounting frame 1 along the pressing direction of the tact switch 2 to press the tact switch 2; the reset piece 32 is used for driving the reset piece 31 to reset so as to release the pressing of the light touch switch 2 by the push piece 31; the pressing piece 31 is connected with the inflection point mechanism 4, and in the first motion stage, the inflection point mechanism 4 applies resistance to the pressing piece 31; in the second movement phase, the knee mechanism 4 applies an assisting force to the pressing piece 31.

In this embodiment, by providing the pressing member 31, and slidably disposing the pressing member 31 on the mounting bracket 1 along the pressing direction of the tact switch 2, the user can effectively press the tact switch 2 while driving the pressing member 31 to slide on the mounting bracket 1, and after completing the pressing operation, the user cancels the pressing of the pressing member 31, and the pressing member 31 completes the resetting by driving the resetting member 32. The operation is convenient, in addition, the pressing component 3 has a simple structure, and the structure of the switch structure is convenient to simplify. However, the present disclosure does not limit the specific structure of the pressing assembly 3 and the specific movement form of the pressing member 31, and in other embodiments, the pressing member 31 may be rotatably disposed on the mounting bracket 1.

Referring to fig. 1 to 3, the pressing assembly includes a pressing piece 31, a restoring piece 32, and a pressing plate 33; the pressing piece 31 is slidably arranged on the mounting frame 1 along the pressing direction of the tact switch 2 to press the tact switch 2; the pressing plate 33 is rotatably arranged on the mounting frame 1, and in the rotating process of the pressing plate 33, the pressing plate 33 can abut against the pressing piece 31 and drive the pressing piece 31 to slide; the pressing plate 33 is connected with the inflection point mechanism 4, and in the first motion stage, the inflection point mechanism 4 applies resistance to the pressing plate 33; in the second movement phase, the knee mechanism 4 applies an assist force to the pressing plate 33; the reset member 32 is used for driving the reset of the pressing member 31 and the pressing plate 33.

The reason why the pressing plate 33 is provided and the pressing plate 33 is connected to the inflection point mechanism 4 is to increase the pressing stroke of the switch structure and improve the user's pressing experience. In particular, how the pressing plate 33 realizes the increase of the pressing stroke is described below:

firstly, the pressing stroke of the tact switch 2 itself is very short, and if the pressing stroke of the switch structure is made to be the same as the stroke of the tact switch 2, the pressing operation by a user is inconvenient; by arranging the pressing plate 33, and connecting the pressing plate 33 with the inflection point mechanism 4, in the process that the user drives the pressing plate 33 to rotate on the mounting frame 1, in the first motion stage, the rotation process of the pressing plate 33 can be sequentially divided into a first rotation section and a second rotation section, in the first rotation section, the pressing plate 33 rotates under the pressing of the user, but the pressing plate 33 does not abut against the pressing piece 31, and at this time, the pressing plate 33 only receives the resistance from the inflection point mechanism 4; in the second rotation section, the pressing plate 33 abuts against the pressing member 31, and the pressing plate 33 receives resistance from the inflection point mechanism 4 and also receives resistance from the reset member 32; in the process of the first motion phase, the pressing piece 31 can not make any contact with the tact switch 2, so that the pressing stroke of the switch structure is effectively increased, and the pressing experience of a user is effectively improved.

Alternatively, as shown with reference to fig. 2 and 3, the inflection point mechanism 4 includes a first rotating member 41, a second rotating member 42, and an elastic member 43. The first rotating member 41 and the second rotating member 42 are rotatably disposed on the mounting frame 1, the pressing plate 33 is connected to the first rotating member 41 to drive the first rotating member 41 to rotate, the first rotating member 41 is connected to the second rotating member 42 to drive the second rotating member 42 to rotate, the elastic member 43 is disposed on the first rotating member 41 and is used for being connected to the second rotating member 42, and in the first motion stage, the deformation amount of the elastic member 43 under the rotation of the second rotating member 42 is gradually increased and applies resistance to the rotation of the second rotating member 42; in the second movement phase, the elastic member 43 gradually recovers the amount of deformation and applies an assisting force to the rotation of the second rotating member 42.

In this embodiment, during the clockwise rotation of the pressing plate 33 pressed by the user, the first rotating member 41 is driven by the pressing plate 33 to rotate in the counterclockwise direction, and the second rotating member 42 is driven by the first rotating member 41 to rotate in the clockwise direction. During the clockwise rotation of the second rotating element 42, since the second rotating element 42 is connected to the elastic element 43, the deformation of the elastic element 43 will gradually increase, and the elastic force of the elastic element 43 acting on the rotating second rotating element 42 will also gradually increase, i.e. the resistance of the user pressing the pressing plate 33 will gradually increase; when the elastic member 43 is deformed to a certain extent, the elastic member 43 is not deformed by the second rotating member 42, the elastic member 43 gradually recovers its deformation, and the elastic member 43 applies an assisting force to the rotation of the second rotating member 42, that is, the elastic member 43 applies an assisting force to the rotation of the pressing plate 33, in the process of recovering the deformation of the elastic member 43.

That is, in the process that the user presses the pressing plate 33 and drives the tact switch 2 until the pressed state is reached, the elastic member 43 in the inflection point mechanism 4 is deformed and the amount of deformation is gradually increased, and then gradually recovers its deformation; in the process that the amount of deformation of the elastic member 43 is gradually increased, the elastic force of the elastic member 43 is also gradually increased, and the elastic force acts to hinder the rotation of the pressing plate 33; in the process that the elastic member 43 recovers the deformation, the elastic force of the elastic member 43 is gradually reduced, and the elastic force is used for providing the assisting force for the rotation of the pressing plate 33, so that the user can press the pressing plate 33 with a section feeling in the process, and the pressing experience of the user is improved.

Alternatively, as shown in fig. 4 and 5, the first rotating member 41 includes a sleeve 411, the second rotating member 42 includes a blocking plate 421, and the elastic member 43 includes a spring; one end of the sleeve 411 is closed, the other end of the sleeve 411 is open, the sleeve 411 is rotatably arranged on the mounting frame 1 around a first axis intersecting with the axis of the sleeve 411, the closed end of the sleeve 411 is hinged with the pressing plate 33, and a groove 4110 is formed at the open end of the sleeve 411; the spring is arranged inside the sleeve 411 in a direction parallel to the axis of the sleeve 411; the baffle 421 is rotatably disposed on the mounting frame 1 around a second axis parallel to the first axis, and the baffle 421 is inserted into the groove 4110 and is used for abutting against the spring.

In this embodiment, when the sleeve 411 rotates under the driving of the pressing plate 33, the baffle 421 is shifted through the groove 4110, so that the baffle 421 rotates in the opposite direction, in the rotation process of the baffle 421, the spring in the sleeve 411 is continuously pressed to be gradually compressed, when the baffle 421 rotates to the central position of the sleeve 411, the spring moves from one side of the axis of the sleeve 411 to a position parallel to the axis of the sleeve 411, in this position, the spring is in an unstable state, and the baffle 421 can turn over to the other side of the axis of the sleeve 411 under the action of the spring. Thereby achieving the effect of an inflection point.

Referring to fig. 4 and 5, the first rotating member 41 further includes a first driving rod 412 and a first rotating shaft 413, the first rotating shaft 413 is connected to the outer side wall of the sleeve 411 along the direction of the first axis to be rotatably disposed on the mounting bracket 1, and the first driving rod 412 is disposed at the closed end of the sleeve 411; the pressing plate 33 includes a pressing plate body 331 and a hinge portion 332 provided inside the pressing plate body 331, and the first transmission rod 412 is rotatably provided at the hinge portion 332; the second rotating member 42 further includes a second rotating shaft 422 and a spring column 423, the second rotating shaft 422 is connected to the baffle 421 along the second axis direction so as to be rotatably disposed on the mounting bracket 1; the spring pillar 423 is convexly disposed on a side of the baffle 421 for abutting against the spring, so as to be inserted into the spring.

In this embodiment, the first rotating shaft 413 facilitates the rotational connection between the first rotating member 41 and the mounting frame 1, and the first driving rod 412 on the first rotating member 41 and the hinge portion 332 on the pressing plate 33 can be hinged to each other, so that the rotational connection between the first rotating member 41 and the pressing plate 33 can be realized. The second rotating shaft 422 on the second rotating member 42 facilitates the rotating connection with the mounting rack 1; in addition, the spring column 423 is arranged on one side of the baffle 421, which is used for abutting against the spring, so as to be inserted into the spring, so that the spring always abuts against the baffle 421 in the rotating process of the baffle 421, and the baffle 421 cannot be separated.

The first rotating member 41 is an integrally formed structure, and/or the second rotating member 42 is an integrally formed structure, which facilitates the manufacturing and processing of the first rotating member 41 and/or the second rotating member 42, and reduces the manufacturing difficulty.

Alternatively, as shown in fig. 1 to 3, a pressing groove 10 extending in a pressing direction is formed on the mounting bracket 1, and the tact switch 2 is disposed on an inner bottom wall of the pressing groove 10; the pressing member 31 includes a pressing cap 311 and a protruding block 312, the pressing cap 311 is slidably disposed in the pressing groove 10 along the pressing direction, and the protruding block 312 is disposed inside the pressing cap 311 for abutting against the tact switch 2.

Firstly, the tact switch 2 is arranged on the inner bottom wall of the pressing groove 10, and the tact switch 2 can be prevented from being damaged by the protection of the pressing groove 10; secondly, the pressing groove 10 can facilitate the sliding of the pressing member 31; in addition, the pressing piece 31 is provided as two parts, namely, a pressing cap 311 and a protruding block 312, the pressing cap 311 is used for forming a sliding fit with the groove wall of the pressing groove 10, and the protruding block 312 is used for pressing the tact switch 2.

Alternatively, as shown in fig. 2 and 3, the reset member 32 includes a reset spring, the reset spring is disposed in the pressing groove 10, and two ends of the reset spring are respectively used for abutting against the inner side of the pressing cap 311 and the inner bottom wall of the pressing groove 10. The return spring is continuously compressed during the pressing of the pressing cap 311, and after the pressing is completed, the pressing cap 311 is returned by the return spring.

The tact switch 2 is provided in plural, and the pressing member 3 and the inflection point mechanism 4 are provided in plural in one-to-one correspondence with the plural tact switches 2, so that on-off control of different electric devices and the like can be realized in one switch structure.

Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure. This application is intended to cover any variations, uses, or adaptations of the disclosure following, in general, the principles of the disclosure and including such departures from the present disclosure as come within known or customary practice within the art to which the disclosure pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

It will be understood that the present disclosure is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims (10)

1. A switch structure, characterized in that it comprises:

a mounting frame (1);

the tact switch (2) is arranged on the mounting rack (1);

the pressing component (3) is movably arranged on the mounting rack (1) to press the tact switch (2);

the inflection point mechanism (4) is connected with the pressing component (3), and the pressing component (3) has a first motion stage and a second motion stage in sequence in the process of pressing the tact switch (2);

-in the first movement phase, the knee mechanism (4) applies a resistance force to the pressing assembly (3); in the second movement phase, the knee mechanism (4) applies an assistance force to the pressing assembly (3).

2. The switch structure according to claim 1, characterized in that said pressing assembly (3) comprises a pressing member (31) and a resetting member (32);

the pressing piece (31) is slidably arranged on the mounting rack (1) along the pressing direction of the tact switch (2) so as to press the tact switch (2);

the resetting piece (32) is used for driving the pressing piece (31) to reset so as to release the pressing of the light touch switch (2) by the pressing piece (31);

the pressing piece (31) is connected with the inflection point mechanism (4), and the inflection point mechanism (4) applies resistance to the pressing piece (31) in the first motion stage; in the second movement phase, the knee mechanism (4) applies an assistance force to the pressing piece (31).

3. The switch structure according to claim 1, characterized in that said pressing assembly comprises a pressing member (31), a resetting member (32) and a pressing plate (33);

the pressing piece (31) is slidably arranged on the mounting rack (1) along the pressing direction of the tact switch (2) so as to press the tact switch (2);

the pressing plate (33) is rotatably arranged on the mounting frame (1), and in the rotating process of the pressing plate (33), the pressing plate (33) can be abutted against the pressing piece (31) and drive the pressing piece (31) to slide;

the pressing plate (33) is connected with the inflection point mechanism (4), and the inflection point mechanism (4) applies resistance to the pressing plate (33) in the first motion stage; in the second movement phase, the knee mechanism (4) applies an assistance force to the pressing plate (33);

the resetting piece (32) is used for driving the pressing piece (31) and the pressing plate (33) to reset.

4. A switch arrangement according to claim 3, characterized in that the knee mechanism (4) comprises a first rotary member (41), a second rotary member (42) and an elastic member (43);

the first rotating part (41) and the second rotating part (42) are both rotatably arranged on the mounting rack (1), the pressing plate (33) is connected with the first rotating part (41) to drive the first rotating part (41) to rotate, the first rotating part (41) is connected with the second rotating part (42) to drive the second rotating part (42) to rotate, the elastic part (43) is arranged on the first rotating part (41) and is used for being connected with the second rotating part (42),

in the first movement phase, the deformation amount of the elastic element (43) under the rotation of the second rotating element (42) is gradually increased and resistance is applied to the rotation of the second rotating element (42); in the second movement phase, the elastic element (43) gradually restores the deformation amount and exerts an assisting force on the rotation of the second rotation element (42).

5. The switch structure according to claim 4, characterized in that said first rotating member (41) comprises a sleeve (411), said second rotating member (42) comprises a shutter (421), said elastic member (43) comprises a spring;

one end of the sleeve (411) is closed, the other end of the sleeve is open, the sleeve (411) is rotatably arranged on the mounting frame (1) around a first axis intersecting with the axis of the sleeve, the closed end of the sleeve (411) is hinged with the pressing plate (33), and a groove (4110) is formed at the open end of the sleeve (411);

the spring is arranged inside the sleeve (411) in a direction parallel to the axis of the sleeve (411);

the baffle (421) is rotatably arranged on the mounting frame (1) around a second axis parallel to the first axis, and the baffle (421) is used for being inserted into the groove (4110) and is used for abutting against the spring.

6. The switch structure of claim 5,

the first rotating member (41) further comprises a first transmission rod (412) and a first rotating shaft (413), the first rotating shaft (413) is connected to the outer side wall of the sleeve (411) along the direction of the first axis so as to be rotatably arranged on the mounting frame (1), and the first transmission rod (412) is arranged at the closed end of the sleeve (411);

the pressing plate (33) comprises a pressing plate body (331) and a hinge part (332) arranged on the inner side of the pressing plate body (331), and the first transmission rod (412) is rotatably arranged on the hinge part (332);

the second rotating part (42) further comprises a second rotating shaft (422) and a spring column (423), and the second rotating shaft (422) is connected to the baffle plate (421) along the direction of the second axis so as to be rotatably arranged on the mounting rack (1); the spring column (423) is convexly arranged on one side of the baffle (421) which is used for abutting against the spring, so as to be inserted into the spring.

7. The switch structure according to claim 6, characterized in that said first rotating member (41) is of one-piece construction and/or said second rotating member (42) is of one-piece construction.

8. The switch structure according to claim 2 or 3, characterized in that the mounting bracket (1) is formed with a pressing groove (10) extending in the pressing direction, and the tact switch (2) is provided on an inner bottom wall of the pressing groove (10);

the pressing piece (31) comprises a pressing cap (311) and a protruding block (312), the pressing cap (311) is slidably arranged in the pressing groove (10) along the pressing direction, and the protruding block (312) is arranged on the inner side of the pressing cap (311) and used for abutting against the light touch switch (2).

9. The switch structure according to claim 8, characterized in that said return element (32) comprises a return spring, said return spring is arranged in said pressing groove (10), and two ends of said return spring are respectively used for abutting against the inner side of said pressing cap (311) and the inner bottom wall of said pressing groove (10).

10. The switch structure according to claim 1, wherein the tact switch (2) is provided in plurality, and the pressing member (3) and the knee mechanism (4) are each provided in plurality in one-to-one correspondence with the plurality of tact switches (2).

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