JP4355553B2 - Input key switch - Google Patents

Description

The present invention relates to an input key switch for inputting information to an electronic device.

Conventionally, as an input key switch for inputting information to an electronic device, a cross key used for moving a cursor displayed on a display screen of a computer, an image displayed on a television screen of a video game machine, or the like A switch is known (see, for example, Patent Document 1). The cross key switch has fixed contacts arranged in the four cross directions on the surface of the substrate, and a key extending in the four cross directions corresponding to the fixed contacts in the four cross directions via a rubber sheet above these fixed contacts. In addition to disposing the top, movable contacts facing the fixed contact are arranged in the four cross-directions on the bottom surface of the rubber sheet, and the key top is swung in one of the four cross-directions. The fixed contact and the movable contact corresponding to the swing direction are formed to contact each other.

There is also known a joystick used to control various devices and move images displayed on the television screen of a video game machine (see, for example, Patent Document 2). The joystick is arranged on the support plate in one or more stages surrounding the support plate, an operation lever having a substantially intermediate portion attached so as to be swingable and / or rotatable with respect to the support plate. The micro switch group is provided, and a guide plate having a deformed guide hole that can be inserted so that the free end side of the operation lever can swing.
JP 11-194886 A JP-A-6-267374

However, in the above-described prior art, the example of the cross key switch presses the end of one of the four cross directions of the key top with the fingertip in order to indicate one of the four directions. For this reason, in order to change the direction of the cruciform four directions indicated by the cross key switch, the fingertip must be moved to one of the cruciform four ends of the key top. There is a problem that it is unsuitable for application to an input device that simultaneously operates a key switch to input various types of information.

In addition, in the example of the joystick, in order to indicate any one direction, the operation lever must be grasped with a hand or moved in any one direction with the fingertip. Similarly, there is a problem that it is not suitable for application to an input device that simultaneously operates a plurality of input key switches with one hand and inputs various types of information at high speed.

The present invention has been made in view of such a situation, and provides an input key switch suitable for an input device that simultaneously operates a plurality of input key switches with one hand and inputs various types of information at high speed. Objective.

In order to solve the above-described problems, the input key switch according to the present invention employs the following means.

That is, the invention according to claim 1 is an input key switch for inputting information to an electronic device, and includes a base, a restoration cam having a triangular pyramid-shaped projection provided on the base, and the restoration cam surface. A key top having a follower to be urged and movable in parallel with the base surface; and a plurality of switches that open and close by the parallel movement of the key top; The restoration cam can be detected by the triangular pyramidal protrusion even when the key top moves in an intermediate direction other than a predetermined direction so that the moving direction of the key top corresponds to the contact position of the switch. It is characterized by restricting to move in a predetermined direction .

The invention according to claim 2 is the part according to claim 1 , further comprising an amplifying mechanism for amplifying the horizontal movement amount of the key top, wherein the movement amount of the key top in the amplification mechanism is amplified. The above-mentioned restricting member is provided.

According to the first aspect of the present invention, since the key top can be operated without moving the fingertip without moving the fingertip on the surface of the keytop, the amount of movement of the fingertip for inputting information is reduced. Therefore, it is possible to provide an input key switch suitable for an input device that simultaneously operates a plurality of input key switches with one hand and inputs various types of information at high speed.

According to the first aspect of the present invention, when the key top is moved in the direction to close the contact of the desired switch by applying a horizontal force to the key top, the movement direction of the key top is accurately desired. When it is not in the direction to close the contact of the switch, it is regulated by the regulating force so that it points in the correct direction, so it is possible to close the desired switch contact by rough key top operation Incorrect operation can be prevented.

According to the second aspect of the present invention, since the horizontal movement amount of the key top is amplified by the amplification mechanism, the key top moves in the horizontal direction even when the horizontal movement amount of the key top is very small. It is possible to secure a stroke that regulates the direction to be performed.

Embodiments of an input key switch according to the present invention will be described below with reference to the drawings. 1 and 2 are diagrams illustrating a first embodiment of an input key switch according to the present invention.

FIG. 1 is a diagram showing an input key switch 10 of the present embodiment. FIG. 1A is a top view of the input key switch 10, and FIG. 1B is a longitudinal sectional view of the input key switch 10. The input key switch 10 includes a key top 12. The key top 12 is formed in a cylindrical shape into which a fingertip having an upper surface is fitted. The opening of the key top 12 is formed in a shape and / or material in which a fingertip fits and a frictional force acts on the fingertip when the keytop 12 is operated with the fingertip. A switch 14 is provided below the key top 12. The switch 14 is fixed to the substrate 16. A plurality (three in the figure) of switches 14 are arranged on the same circumference as the circumference of the key top 12. The key top 12 is held by a holding member 18. The holding member 18 is connected to the shaft 20 so as to be swingable. The lower end of the shaft 20 is fixed to the substrate 16.

FIG. 2 is a diagram for explaining the operation of the input key switch 10. 2 (a) is a longitudinal sectional view of the input key switch 10, FIG. 2 (b) is a top view of the input key switch 10, and FIG. 2 (c) is the force acting on the key top 12 where the contact of the switch A is closed. FIG. 2D is a diagram showing a vector region, and FIG. 2D is a diagram showing a vector region of a force acting on the key top 12 where the contacts of one switch or two switches are closed. When a fingertip is fitted into the opening of the key top 12 and a force is applied in the horizontal direction, the key top 12 swings about the connecting portion between the holding member 18 and the shaft 20. When the key top 12 swings, the holding member 18 holding the key top 12 is displaced in the vertical direction, and one of a plurality of (three in the figure) switches or two adjacent switches are pressed to switch. 14 contacts are closed. When no force is applied to the key top 12, all the contacts of the switch 14 are open. When a fingertip is fitted into the opening of the key top 12 and a force is applied in the left direction in FIG. 2B, the contact of the switch A is closed, and when a force is applied in the lower left direction, both the contacts of the switch A and the switch B are applied. When the force is applied in the lower right direction, the contact of the switch B is closed. When the force is applied in the right direction, both the contacts of the switch B and the switch C are closed, and when the force is applied in the upper right direction. When the contact of the switch C is closed and a force is applied in the upper left direction, both the contacts of the switch A and the switch C are closed. As a result, the number of switches 14 of the input key switch 10 is doubled by the combination of opening and closing the contacts of a plurality of switches (three in the figure) including the state where no force is applied to the key top 12. It is possible to detect the number of states (seven states in the case of the figure).

Next, the balance of forces acting on the input key switch 10 will be described. When a fingertip is fitted in the opening of the key top 12 and a horizontal horizontal force Fh is applied to the key top 12, the horizontal force Fh balances the fulcrum reaction force and the fulcrum P of the switch reaction force with the center moment. As shown in FIG. 2C, when the horizontal force Fh is applied in the direction sandwiched between the switch A and the switch B, the force is supported by the switch A and the switch B, so the horizontal force Fh can be considered as the resultant force of Fa and Fb. . The change in force due to the displacement of the key top 12 is ignored. Regardless of whether the contact of switch B is opened or closed, the contact of switch A opens and closes depending on whether the component Fa in the switch A direction of the horizontal force Fh exceeds the threshold value. The contact of A is closed. Similarly, when the direction of the horizontal force Fh is between the switch A and the switch C, the oblique lattice range becomes the vector region of the horizontal force Fh in which the contact of the switch A is closed. The same applies to the vector region of the horizontal force Fh in which the contacts for the other switches B and C are closed. As shown in FIG. 2D, the contacts of two adjacent switches are closed in the vertical hatching region where the regions where the switch contacts are closed overlap. In the lateral hatching area where the above-mentioned area where the contact of the switch is closed does not overlap, the contact of one switch is closed.

According to this embodiment, the key top 12 can be swung by fitting a fingertip into the opening of the key top 12, and the amount of rocking of the key top 12 for closing the contact of the switch 14 is very small. The key top 12 can be operated without moving the fingertip without moving the fingertip on the surface of the top 12. Therefore, it is possible to provide an input key switch suitable for an input device that inputs a plurality of types of information at high speed by simultaneously operating a plurality of input key switches with one hand with a small movement amount of a fingertip for inputting information. .

Next, a second embodiment of the input key switch according to the present invention will be described. 3 and 4 are diagrams illustrating a second embodiment of the input key switch according to the present invention.

FIG. 3 is a diagram showing the principle of the input key switch 30 of the present embodiment. FIG. 3A is a perspective view showing the principle of the input key switch 30, and FIG. 3B is a plan view showing the force acting on the input key switch 30. In the operation of the input key switch, the direction of the fingertip force applied to the input key switch is made to correspond to the contact position of the switch. For this reason, when the force of the fingertip is applied to the input key switch in the direction between the contact points of the switch so that the contact point of the switch provided in the predetermined direction is closed, the restriction force is applied to the input key switch. is required. FIG. 3A is a perspective view showing the principle of the input key switch 30 in which the contact points of the switch are provided in the six equiangular directions. The input key switch 30 has a three-dimensional cam structure including a moving part A, a restoration cam B, and a base C. The moving part A moves in a plane parallel to the base C by an external operation. The restoring cam B is constrained in a plane parallel to the base C, can be translated in a direction perpendicular to the surface of the base C, and is pressed against the moving part A by a restoring spring. The restoring cam B includes a triangular pyramidal projection whose one surface is in contact with the base C with the six equiangular directions protruding in six equiangular directions as one vertex. From the moving portion A, six rods protrude from the tip portions of the six triangular pyramidal projections of the restoring cam B to make point contact. Both the contact portions of the restoring cam B and the rod have sufficient hardness and wear resistance, and friction is negligible. The moving part A can smoothly translate in six directions except for the triangular pyramidal protrusions of the restoring cam B. When the moving part A is moved in the intermediate direction other than the six directions by the force F, the slope of the triangular pyramidal protrusion of the restoring cam B is pushed down. The restoring spring reaction force thereby is applied as a cam reaction force K in the inclined direction by pushing the tip of the rod of the moving part A. As a result, the moving part A can move in the original smooth translation direction R. Therefore, the cam reaction force K is a regulating force that regulates the operation direction of the moving part A. Although not shown, switches are provided in six directions, respectively, and a force that opens the contact points of the switches acts in the radial direction. When the radial force in the switch contact direction exceeds a certain value, the switch contact is closed. A force obtained by adding the cam reaction force K from the restoring cam B and the switch reaction force becomes a reaction force to the external operation of the moving part A. The operation feeling of the input key switch 30 is only the feeling that the contact of the switch opens and closes in the six directions where the switch is provided. For a force in a different direction, a cam reaction force K and a switch reaction force due to the restoring spring are felt. In this example, six directions are used, but other numbers may be used, and the directions may not be equiangular. As described above, according to the present input key switch 30, even when the direction of the force applied to the fingertip during operation is slightly different from the intended direction, it is guided in a predetermined direction. Can be closed.

FIG. 4 is a diagram showing the input key switch 30. 4A is a cross-sectional view taken along line AA of the input key switch 30, FIG. 4B is a cross-sectional view taken along line BB of the input key switch 30, and FIG. 4C is a cross-sectional view taken along line C-C of the input key switch 30. 4D is a sectional view taken along the line DD of the input key switch 30, FIG. 4E is a sectional view taken along the line EE of the input key switch 30, and FIG. FIG. 4G is an enlarged perspective view of the cam phase tips 44 and 50. The input key switch 30 includes a key top 32. The key top 32 is formed in a cylindrical shape into which a fingertip having an upper surface is fitted. The upper end of the key top 32 is bent outward. The lower end of the key top 32 is joined to the key mover 34. The four corners of the key mover 34 extend downward and contact the substrate 35. A key mover pressing plate 38 for pressing the upper surface of the key mover 34 is provided above the key mover 34 and outside the key top 32. A side wall 40 of the input key switch 30 that supports the key mover presser plate 38 is joined to the lower surface of the key mover presser plate 38. The lower surface of the side wall 40 is bonded to the substrate 35. Below the key slider 34, a slider 36 is provided. The slider 36 is formed of a slide portion 36a that is provided at the front and rear end portions and abuts the side wall 40 so as to be slidable in the left-right direction, and a beam portion 36b that connects the slide portion 36a at the front and rear end portions. A slide guide 42 is provided on the lower surface of the key slider 34 so that the key slider 34 can slide in the front-rear direction with respect to the left and right ends of the beam portion 36b of the slider 36. In addition, a plurality of triangular pyramid-shaped cam phase tips 44 are provided on the lower surface of the key mover 34 so that one surface is in contact with the lower surface of the key mover 34 and the tip end faces radially outward (six in the figure). It is arranged in a substantially arc shape. In addition, a plurality of switch pushers 46 (six in the figure) are arranged in a substantially circular arc shape at a ratio of one between the cam phase chips 44 on the lower surface of the key mover 34. A leaf spring 48 is provided below the slider 36. The leaf spring 48 is formed with a plurality of arms 48a and 48b (six in the drawing) in a radial manner. The arm 48b is bent obliquely upward. On the upper surface of the leaf spring 48, a triangular pyramid-shaped cam phase tip 50 is arranged on the arm 48a in a substantially arc shape so that one surface contacts the upper surface of the leaf spring 48 and the tip portion is directed radially inward. ing. The cam phase tip 50 is disposed at a position of a leaf spring 48 whose ridge line faces the cam phase tip 44. Further, one switch contact 52 is provided between the cam phase chips 50 on the lower surface of the leaf spring 48. One switch contact 52 is disposed at a position of the leaf spring 48 that abuts against the other switch contact 54 by causing the key slider 34 to move in parallel to bend the leaf spring 48 downward. Below the leaf spring 48, the other switch contact 54 is provided at a position on the substrate 35 opposite to the one switch contact 52 provided on the lower surface of the leaf spring 48.

Next, the operation of the input key switch 30 configured as described above will be described. When a fingertip is fitted to the key top 32 and a force is applied in the left-right direction, the slider 36 translates in the left-right direction, and the key top 32 translates in the left-right direction. When a fingertip is fitted to the key top 32 and a force is applied in the front-rear direction, the key slider 34 is translated in the front-rear direction, and the key top 32 is translated in the front-rear direction. When a fingertip is fitted on the key top 32 and a force is applied in an oblique direction, the slider 36 and the key slider 34 are translated in the left and right and front and rear directions, and the key top 32 is translated in the oblique direction. When the key top 32 moves in parallel, the cam phase tips 44 and 50 apply a regulating force to regulate the translation direction. And the contact of the switch corresponding to the regulated direction is closed.

According to the present embodiment, a fingertip can be fitted into the opening of the key top 32 to move the key top 32 in parallel, and the amount of parallel movement of the key top 32 for closing the switch contacts 52 and 54 is very small. The key top 32 can be operated without releasing the fingertip without moving the fingertip on the surface of the keytop 32. Therefore, it is possible to provide an input key switch suitable for an input device that inputs a plurality of types of information at high speed by simultaneously operating a plurality of input key switches with one hand with a small movement amount of a fingertip for inputting information. .

Further, according to the present embodiment, when applying the horizontal force to the key top 32 to close the contact of the desired switch, the direction of the horizontal force applied to the key top 32 is accurately desired. If it is not in the direction to close the contact of the switch, it is regulated by the regulating force so that it points in the correct direction, so the desired switch contact can be closed by rough key top 32 operation Can prevent erroneous operation.

In addition, according to the present embodiment, the key top 32 can be translated in two orthogonal directions to open and close the switch contacts, so that a stroke for regulating the direction in which the key top 32 moves is secured. The input key switch can be made thin.

Next, a third embodiment of the input key switch according to the present invention will be described. 5 and 6 are diagrams illustrating a third embodiment of the input key switch according to the present invention.

FIG. 5 is a diagram showing the principle of the input key switch 60 of the present embodiment. FIG. 5A is a perspective view showing the principle of the input key switch 60, and FIG. 5B is a plan view showing the force acting on the input key switch 60. In the operation of the input key switch, the direction of the fingertip force applied to the input key switch is made to correspond to the contact position of the switch. For this reason, when the force of the fingertip is applied to the input key switch in the direction between the contact points of the switch so that the contact point of the switch provided in the predetermined direction is closed, the restriction force is applied to the input key switch. is required. FIG. 5A is a perspective view showing the principle of an input key switch 60 in which switch contacts are provided in six equiangular directions. The input key switch 60 has a three-dimensional cam structure including a moving point A, a restoring cam B, and a base C. The moving point A moves in a plane parallel to the base C by an external operation. The restoring cam B is constrained in a plane parallel to the base C, can be translated in a direction perpendicular to the surface of the base C, and is pressed against the moving point A by a restoring spring. The restoration cam B is formed by arranging triangular pyramidal protrusions whose one surface is in contact with the base C with one apex at the center in six equiangular directions. From the moving point A, a stick protrudes from the center of the restoring cam B to make point contact. Both the contact portions of the restoring cam B and the rod have sufficient hardness and wear resistance, and friction is negligible. The moving point A can be smoothly translated in six directions except for the triangular pyramidal protrusions of the restoring cam B. When the moving point A moves in the intermediate direction other than the six directions by the force F, the slope of the triangular pyramidal protrusion of the restoring cam B is pushed down. The restoring spring reaction force thereby is applied as a cam reaction force K in the direction of the slope by pushing the tip of the rod at the moving point A. As a result, the moving point A can move in the original smooth translation direction R. Therefore, the cam reaction force K is a regulating force that regulates the operation direction of the moving point A. Although not shown, switches are provided in six directions, respectively, and a force that opens the contact points of the switches acts in the radial direction. When the radial force in the switch contact direction exceeds a certain value, the switch contact is closed. The force obtained by adding the cam reaction force K from the restoring cam B and the switch reaction force becomes the reaction force of the moving point A to the external operation. The sense of operation of the input key switch 60 is only the sense that the switch contacts open and close in the six directions where the switch is provided. For a force in a different direction, a cam reaction force K and a switch reaction force due to the restoring spring are felt. In this example, six directions are used, but other numbers may be used, and the directions may not be equiangular. As described above, according to the input key switch 60, even when the direction of the force applied to the fingertip during operation is slightly different from the intended direction, the switch is guided in a predetermined direction with a rough sense of operation. Can be closed.

FIG. 6 is a diagram showing the input key switch 60. 6A is a cross-sectional view taken along line AA of the input key switch 60, FIG. 6B is a cross-sectional view taken along line BB of the input key switch 60, and FIG. 6C is a cross-sectional view taken along line C-C of the input key switch 60. 6D is a cross-sectional view taken along the line DD of the input key switch 60, FIG. 6E is a cross-sectional view taken along the line EE of the input key switch 60, and FIG. FIG. 6G is a cross-sectional view of the input key switch 60 taken along the line GG. The input key switch 60 includes a key top 62. The key top 62 is formed in a cylindrical shape into which a fingertip having an upper surface is fitted. A support shaft 64 that supports the key top 62 is provided on the lower surface of the key top 62. A lower end portion of the support shaft 64 is rotatably connected to the substrate 66. In addition, a plurality of switch pressers 68 are provided on the lower surface of the key top 62 in an equiangular direction from the center of the key top 62 (three in the figure). Between the switch presser 68 and the substrate 66, a plurality of switches (three in the figure) are provided at positions corresponding to the switch presser 68. The switch 70 is fixed to the substrate 66. On the circumference of the key top 62, flanges 72 and 74 are provided at opposing positions. The flange 72 is rotatably connected to an arm 76 that is rotatably connected to the upper surface of the protrusion 66a of the substrate 66. A lever 78 is rotatably connected to the collar portion 74. The collar part 74 is connected to a substantially central part of the insulator 78. One end of the insulator 78 is rotatably connected to an arm 80 that is rotatably connected to the upper surface of the protrusion 66b of the substrate 66. At the other end of the insulator 78, rotors 82 and 84 are provided on the lower surface and the upper surface, respectively. The rotor 82 is in contact with the upper surface of the block 86 urged upward by an elastic member with respect to the substrate 66. The rotor 84 is in contact with a three-dimensional cam 90 formed by arranging a plurality of triangular pyramid protrusions (six in the figure) in an equiangular direction with the center as one vertex and one surface facing upward. The solid cam 90 is fixed to the lower surface of the upper wall 88 fixed to the substrate 66 provided above the insulator 78.

Next, the operation of the input key switch 60 configured as described above will be described. When a fingertip is fitted to the key top 62 and a force is applied in a predetermined horizontal direction, the key top 62 swings with the lower end portion of the support shaft 64 as a fulcrum. When the key top 62 swings, the key top 62 moves in the horizontal direction and the lever 78 moves in the horizontal direction. The amount of movement in the left-right direction of the key top 62 is that the lever 78 is pivotally connected to the arm 80 at one end portion, and the collar portion 74 of the key top 62 is pivotally connected to the substantially central portion of the lever 78. Amplified at the other end of the lever 78, the amount of vertical movement of the key top 62 is linked so that the hook 72 of the key top 62 is pivotable by the arm 76, and the hook 74 of the key top 62 is connected to the lever 78. As a result, it is amplified by Isogo 78. When the lever 78 moves in the horizontal direction, the movement of the rotor 84 is restricted by the three-dimensional cam 90 with a restriction force. As a result, when the moving direction of the rotor 84 is restricted, the moving direction of the lever 78 is restricted, so that the moving direction of the key top 62 is restricted. Then, the switch presser 68 of the key top 62 is displaced in the vertical direction, and the switch contact corresponding to the restricted direction is closed.

According to this embodiment, the key top 62 can be swung by fitting a fingertip into the opening of the key top 62 and the amount of movement of the key top 62 for closing the contact of the switch 70 is very small. The key top 62 can be operated without moving the fingertip on the surface of the top 32 without moving the fingertip. Therefore, it is possible to provide an input key switch suitable for an input device that inputs a plurality of types of information at high speed by simultaneously operating a plurality of input key switches with one hand with a small movement amount of a fingertip for inputting information. .

Further, according to the present embodiment, when applying a horizontal force to the key top 62 to close the contact of the desired switch, the direction of the horizontal force applied to the key top 62 is accurately desired. If it is not in the direction to close the contact of the switch, it is regulated by the regulating force so that it is directed in the correct direction, so the desired switch contact can be closed by operating the rough key top 62 Can prevent erroneous operation.

In addition, according to the present embodiment, since the amount of horizontal movement of the key top 62 is amplified, the direction of movement of the key top 62 in the horizontal direction can be determined even when the amount of horizontal movement of the key top 62 is very small. The stroke to be controlled can be secured.

Further, according to the present embodiment, the other end portion of the lever 78 connected to the key top 62 abuts the block 86 and the three-dimensional cam 90 at the rotors 82 and 84, so that the key top 62 can be moved smoothly. be able to.

Next, a fourth embodiment of the input key switch according to the present invention will be described. FIG. 7 is a view for explaining a fourth embodiment of the input key switch according to the present invention.

FIG. 7 is a diagram showing the input key switch 100 of the present embodiment. The input key switch 100 includes a key top 102. The key top 102 is formed in a cylindrical shape into which a fingertip having an upper surface is fitted. The key top 102 is held by a holding member 106 via a bearing 104 so as to be rotatable in a horizontal plane. A rotary encoder 108 capable of detecting the rotation of the key top 102 is provided on the outer periphery of the key top 102. Below the holding member 106 is provided a switch 110 that can detect a plurality of states in which the key top 102 is displaced.

According to the present embodiment, since the rotation of the key top 102 can be detected by the rotary encoder 108, analog information can be input to the electronic device by rotating the key top 102.

This embodiment can be realized by forming a key top in a horizontal plane in the first to third embodiments and providing a rotary encoder so that the rotation of the key top can be detected.

It is a figure which shows 1st Embodiment of the input key switch which concerns on this invention. It is a figure for demonstrating operation | movement of the input key switch of FIG. It is a figure which shows the principle of 2nd Embodiment of the input key switch which concerns on this invention. It is a figure which shows 2nd Embodiment of the input key switch which concerns on this invention. It is a figure which shows the principle of 3rd Embodiment of the input key switch which concerns on this invention. It is a figure which shows 3rd Embodiment of the input key switch which concerns on this invention. It is a figure which shows 4th Embodiment of the input key switch which concerns on this invention.

10, 30, 60, 100 Input key switch
12, 32, 62, 102 key top
14, 70, 110 switches
52, 54 Switch contact
108 Rotary encoder

Claims (2)

An input key switch for inputting information to an electronic device,
A base, a restoration cam having a triangular pyramidal projection provided on the base, a key top having a follower biased to the restoration cam surface, and movable relative to the base surface; and the key top A plurality of switches that open and close by parallel movement ,
Can detect the opening and closing operation of the switch in the movement operation of the key top,
The restoration cam restricts the key top to move in a predetermined direction by the triangular pyramidal protrusion even when the key top moves in an intermediate direction other than the predetermined direction so that the moving direction of the key top corresponds to the contact position of the switch. An input key switch characterized by It includes an amplification mechanism for amplifying the amount of horizontal movement of the key top, the input of claim 1, wherein the movement amount of the key top in the amplification mechanism is characterized by providing the restricting member to the site to be amplified Key switch.

Images