Abstract: A side keypad assembly includes a pressing surface, an opposite mating surface. The pressing surface includes a plurality of keypads protruded thereon. The mating surface includes a plurality of stepped columns protruded thereon corresponding to the plurality of keypads respectively and a plurality of separating protrusions corresponding to the conjoint portions between every two keypads respectively. The invention also provides a portable electronic device using the side keypad assembly.

Abstract: A control assembly is assembled between a housing and a printed circuit board of an electronic device. The housing defines a mounting hole. The control assembly includes a force member assembled in the mounting hole, a switch electrically fixed on the printed circuit board under the force member, and a resilient member abutted between the force member and the printed circuit board. The resilient member is compressed to allow the force member to contact the switch when external force applied to the force member.

Abstract: A keypad assembly includes a support member, a key switch, a keycap and a resilient member. The key switch is located on the support member, and includes a triggering portion. The keycap is fixed opposite to the triggering portion. The resilient member is fixed to the keycap. The support member and the key switch are located between the keycap and the resilient member. The resilient member is elastically deformed by resisting the support member when the key switch is not triggered, such that the keycap tightly contacts the triggering portion of the key switch.

Abstract: A button assembly for a refrigerator comprises: a case having a cooling chamber, and a door for opening or closing the cooling chamber; a cover mounted to one side of the case, and provided with a plurality of button insertion openings; a substrate fixed to an inner side of the cover, and provided with a plurality of switch buttons; elastic supporters inserted into the button insertion openings of the cover, and covering the switch buttons of the substrate; and button pads coupled to the elastic supporters, and elastically supported by an elastic force of the elastic supporters when pressed by a user, for switching on/off the switch buttons. The button assembly prevents humid air from being introduced thereinto, and simplifies the components to enhance the reliability and productivity. The button assembly enhances appearance around the buttons.

Abstract: An apparatus for key actuation of an electronic device comprising a linear bearing configured for transmitting user actuation, and a complementary guide portion, wherein the linear bearing and the guide portion are arranged to allow the linear bearing to move reciprocally relative to the guide portion for key activation, and wherein both the linear bearing and the guide portion comprise a material with a hardness substantially between 6 Mohrs and 10 Mohrs.

Abstract: A keyboard having: a base panel, a switch panel including a hole portion, a membrane sheet including a contact portion, a key top adapted to be depressed for switching the contact portion ON, and a housing supporting and guiding the key top to move freely in a vertical direction, including each a tube portion on an upper end side having a guide hole formed for inserting a stem formed integrally with the key top and a flange portion on an lower end side extending laterally around the tube portion in a size larger than the hole portion; wherein the housing is inserted into the hole portion from a back side of the switch panel, the flange portion being attached to the back side of the switch panel.

Abstract: A pushbutton switch assembly includes a molded housing body with an integral central barrel, a pushbutton mounted in the housing body and having a stem plunger received in and longitudinally movable in the barrel with the operation of the pushbutton and a return spring for returning the pushbutton to a normal position when it is depressed and released. The central barrel and plunger are of a matching non-round shape thereby preventing rotation of the button in relation to the housing.

Abstract: A technique of preventing permeation of liquid and dust to electronic parts within a housing of an input device for an in-vehicle device. An input device of an in-vehicle device comprises a housing and a substrate stored in the housing. The housing comprises a button, a rod hole for guiding vertically a rod positioned under the button, taking the top of the button as an upper side, and the rod inserted in the rod hole. The substrate comprises an input element positioned under the rod. The rod is fitted with a covering member that covers the rod hole from above.

Abstract: A tamper-resistant keypad is described. The keypad includes a keycap for actuation by a user. An actuator includes a first end that is coupled to the keycap. A frame having an aperture is adapted to receive the actuator such that the second end of the actuator is captured by the frame. The actuator is prevented from being removed from the frame.

Abstract: A key button mechanism mounted to a housing of an electronic device, comprises a key body and an actuator. The key body is mounted to the housing, the key body has a contacting portion protruding therefrom. The actuator has a resisting portion and a driving portion protruding from an end of the resisting portion. The actuator is rotatably mounted to the housing and the resisting portion is aligned with the contacting portion such that when the key body is operated, the contacting portion pushes the resisting portion to make the driving portion touch the printed circuit board.

Abstract: Described herein are techniques related to a leveled touchsurface with planar translational responsiveness to vertical travel. Examples of a touchsurface include a key of a keyboard, touchpad of a laptop, or a touchscreen of a smartphone or tablet computer. With the techniques described herein, the touchsurface is constrained to remain in a level orientation during planar translational movement between depressed and unpressed positions along a diagonal line with respect to a vertical axis. Also, with the techniques described herein, a planar-translation-effecting mechanism imparts a planar translation to the touchsurface while it travels vertically (e.g., downward) as the user presses the touchsurface. This Abstract is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Abstract: An uniformly self-luminous keyboard device comprises a housing and a keyboard unit. The housing includes an upper casing and a lower casing, which can be assembled together. After the upper casing and the lower casing are assembled together, an accommodation space is formed therebetween. The upper casing has an opening interconnecting the accommodation space. The keyboard unit is arranged in the accommodation space and includes a plurality of press members passing through the opening and moved by a force to have a displacement, and a baseplate supporting the press members. A light conduction space is formed between the baseplate and the lower casing. A light emitting unit is arranged inside the light conduction space. The height of the light conduction space decreases with the distance to the light emitting unit, whereby light is uniformly distributed over the bottom of the keyboard unit. Thus is achieved the uniformly self-luminous keyboard device.

Abstract: A portable electronic device attached to a housing includes a button, a elastic plate and a switch. The housing defines a through button hole. The button includes an operating portion and a resisting portion. The operating portion extends out of the housing from the button hole. The elastic plate is fixed to the housing. The elastic plate includes an arched portion and defines a guiding hole, the arched portion resists the button. The resisting portion is received in the guiding hole. The resisting portion contacts the switch to form an electronic signal when the button is pressed down. The arched portion of the elastic plate pushes the button to return to original position by a rebounding force when the button is released.

Abstract: A thin key structure includes a keycap, a key body, an elastic piece and a base. The keycap has a first side wall. The key body has a second side wall forming a hollow chamber in which the keycap can be put to connect the elastic piece. The inner of the second side wall is provided with guiding portions for guiding the keycap to move steadily in the key body. With the keycap being put in the key body, the total height of the key structure can be reduced, and the vertical moving distance of the keycap with respect to the key body to press the elastic piece can be shortened. Thus, the thin key structure can be made more compact.

Abstract: An electronics enclosure and associated components form a self-contained, unitized assembly including control buttons and illuminated indicator elements, that can be mated as a single piece with an outer user interface control panel fascia. A front panel of the electronics enclosure provides a mounting location for various buttons and lighted indicators that will show through mating apertures provided in the control panel fascia. This may include light pipe collars and integral spring levers. Specially configured cup structures may be integrally molded at the ends of the spring levers to provide electrostatic discharge (ESD) protection. A mount of planar spring button pieces on the front enclosure panel, over the associated spring levers, results in an assembly incorporating two springs serving to bias the associated button to its return position, and eliminating any rattle or looseness of the parts.

Abstract: A power button assembly includes a printed circuit board having a first surface and a second surface opposite to the first surface, a switch positioned on the first surface, a dome positioned on the second surface corresponding to the switch, a push button resiliently abutted by the dome. One can depress the push button towards the dome, which then capable of depressing the dome to activate the switch. A support plate is engaged with the printed circuit board. One of the support plate and the push button includes two pairs of hook portions, and the other includes two latching portions for engaging with the two pairs of hook portions.

Abstract: A button switch includes a main body. The main body includes a switch member therein. The switch member has a start portion and a stop portion to connect with a start button and a stop button, respectively. The stop button has a first position and a second position. In a normal state, the stop button is located at the first position and doesn't drive the stop portion. When the stop button is at the second position, the stop button will drive the stop portion. Thus, the operator is enforced to press the stop button again and the stop button is returned to the first position to start the switch member, preventing the operator to press the start button unexpectedly to start the switch member.

Abstract: A power switch module includes a printed circuit board having a switch, a support plate engaging the printed circuit board, a control to activate the switch, and an elastic member fixed to the support plate and positioned between the printed circuit board and the control. The elastic member has a plurality of resisting portions thereon to elastically resist the control. One of the elastic member and the control has a plurality of hook portions, and the other has a plurality of latching portions engaging with the hook portions.

Abstract: A lighting device and a display apparatus are disclosed. The lighting device includes at least one light source installed on a substrate, spaced apart a predetermined distance from each other, and a filter member provided over the at least one light source having a variable thickness. Light emitted from the at least one light source transmits through the filter member. The display apparatus includes a panel that displays an image, a front cover that supports a front edge portion of the panel, and a lighting device mounted in an open portion formed at the front cover, the lighting device being exposed outside.

Abstract: A power button assembly includes a printed circuit board having a switch, a support plate engaging with the printed circuit board, and a push button to activate the switch. The support plate includes abutting portions to elastically abut against the push button, and one of the support plate and the push button includes hook portions, and the other includes latching portions engaging with the hook portions.

Abstract: A button structure for actuating a switch includes a pressing part, a protruding part connected to a side of the pressing part for being driven to actuate the switch when the pressing part is pressed, and a constraining part. An end of the constraining part is connected to the pressing part in an elastically deformable manner. A guiding slot is formed on the constraining part. The button structure further includes a fixing part. An end of the fixing part is disposed inside the guiding slot. The guiding slot slides relative to the fixing part when the pressing part is pressed.

Abstract: A key structure of a keyboard includes a cap having a cover and a key post protruded under the cover, a key base which has a base board, restraining posts and a guiding post protruded on the base board with being arranged and spaced to surround a receiving space thereamong, and a resilient dome with a recessed passageway mounted between the cover and the base board to receive the key post and the posts in the passageway. The key post includes a base pillar and guiding ribs arranged around the base pillar. A guiding channel is opened in an inside of the guiding post to communicate with the receiving space and passes through a top of the guiding post. The key post is movably inserted in the receiving space with one guiding rib being slidably inserted in the guiding channel and the other guiding ribs being resisted against the respective restraining posts.

Abstract: A pushbutton switch includes a pushbutton for changing a switching mode of a tact switch provided on a switch holder fixedly disposed within a casing. The pushbutton includes a push operation portion disposed in a through hole provided in the casing and a collar that protrudes outwardly from the push operation portion and faces an inner face of the casing at the peripheral edge of the through hole. The pushbutton is connected to the switch holder and resiliently urged toward the side on which the collar gets closer to the inner face of the casing. Projections projecting toward the inner face of the casing are projectingly provided integrally at a plurality of positions spaced in the peripheral direction on an opposing face, of the collar of the pushbutton, that is opposed to the inner face of the casing. This prevents a freezing problem in the operation of a pushbutton.

Abstract: A key structure of a keyboard, comprising: a backplane and a plurality of key caps. The backplane is concaved a plurality of grooves. A frame is deposed on the groove, and outside of the frame two fixed bases and two positioning columns are correspondingly deposed on the opposite sides. A clamp is deposed on the fixed base. A link bar, consists of a cross bar and two struts. The cross bar and the struts are mutually perpendicular and shown as an upside-down U shape. A key cap, in which a convex column is extended from the inside of the key cap, and two clips are protruded respectively on the opposite sides of the convex column, as well as a slot is deposed on the clip. The clips are adapted to position the cross bar of the link bar to a clamp of a fixed base on the backplane. And two struts are adapted to be held by the positioning column, so that the two struts only can be moved up and down and will not mismatch.

Abstract: A rotary knob assembly (100) includes a fixed raised boss (110) having a boss cavity (107) and a knob (102) optionally having a rotary switch stem (104) therein. The knob can include a portion that axially resides within the boss cavity such that impacts to the knob transfers to the fixed raised boss. The knob can further include a rigid core member (106) and an outer over-molded portion (108) over-molded on to the rigid core member. The fixed raised boss can include an outer circumference (118) and an inner circumference (116). The inner circumference of the boss and a portion of the rigid core member and the outer circumference of the boss and the outer mover-molded portion form a knob-boss interface (117) that sustains impacts to the rotary knob assembly while isolating a rotary switch (112) from impacts.

Abstract: A switch assembly includes a base, a switch member and a switch cap. The switch member is received in a recess of the base and pivotally connected to the base. The switch member has a pressing piece which is lowered to push a bi-metallic strip in the base. The switch member has engagement portions. A switch cap has a hook unit on a bottom thereof and the hook unit includes a first hook, a second hook and a third hook. The first and second hooks are located at two opposing sides of the switch cap, and the third hook is located at another side of the switch cap. The hook unit is hooked with the engagement portions of the switch member so that the switch cap is connected to the switch member.

Abstract: A keyboard and key structure thereof includes a keycap, an elastic element, a supporting element, a base and a frame. The elastic element is located below the keycap. The supporting element has a supporting part, a connecting part and an end part, wherein the supporting part supports the keycap and the connecting part connects the supporting part and the end part. The base supports the elastic element. The frame secures the end part on the base. A keyboard includes a plurality of key structures.

Abstract: A depressible key structure includes a key frame, a keycap, and plural elastic arms. The key frame has a receiving hole. The keycap is accommodated within the receiving hole, and includes plural outer corner portions. Each of the elastic arms includes an inner fixed arm part, at least one outer movable arm part, and a corner transition part interconnected between the inner fixed arm part and the at least one outer movable arm part. The corner transition parts of the elastic arms correspond to respective outer corner portions of the keycap. Each of the inner fixed arm parts is positioned at an inner edge of a specified side of a bottom surface of the keycap. A corresponding corner transition part is protruded out of the specified side to an adjacent side along a corresponding outer corner portion. The outer movable arm part is fixed on the key frame.

Abstract: A dust-free button assembly is disposed on a substrate carrying a switch to be triggered to generate a signal. The dust-free button assembly includes a flexible member disposed on the substrate and a pressed body disposed above the switch. The pressed body includes a button cap and a post. The button cap includes an upper surface and a recessed lower surface. One end of the post is connected to the lower surface while the other end is connected to the flexible member. An air tunnel runs through the post, and the post includes an outlet communicating the air tunnel. An air-contained-space is defined between the post, the flexible member, and the substrate; and the air tunnel communicates the air-contained-space. When the flexible member is deformed by the post, the air in the air-contained-space is forced to be exhausted through the air tunnel and the outlet to remove dust.

Abstract: The invention relates to a push-button (5) having a housing (10), with which there are associated at least a first actuation member (6) which triggers a haptic control signal and one or more permanent magnet(s) (3) which can be guided past at least a second actuation member (2) which triggers a switching operation, and there is associated with the first actuation member (6), which triggers a haptic response, a control element having a first progressive or degressive control face portion (6.1) and at least a second adjoining control face portion (6.2) which behaves in an inverse manner and along which the actuation member is guided.

Abstract: Push button switch assembly for insertion in a control panel of a domestic appliance, the push button switch assembly comprising at least one push button having a push button cap and a separately formed actuating element, in particular an actuating pin, which extends between the push button cap and an electric switching element of the domestic appliance and upon actuating of the push button cap cooperates therewith and acts on the electric switching element to effect a switching operation, and a frame receiving and guiding the at least one push button cap, wherein at least one spring leg is arranged at the actuating element, which counteracts the actuating of the push button cap.

Abstract: A press switch is composed of a base, a light-emitting device, a housing, a movable seat, and a pressing element. Due to the flat surfaces of the base and the ribs of the movable seat, the area of contact between the base and the movable seat is reduced. In addition, due to the ribs of the movable seat and the flat surfaces of the housing, the area of contact between the movable seat and the housing is also reduced. These reduced areas of contact allow the pressing element to be pressed stably and smoothly.

Abstract: A multi direction switch (100) includes an upper housing (3), a lower housing (6), a bottom cover (11), an elastic ring (5), an actuator (4), an operating button (1), a terminal plate (7), a moveable electrode plate (8), an insulative layer (10), and a fixed electrode plate (9). The upper housing and the lower housing define a channel (361) and a first receiving space (362) for receiving the elastic ring. The bottom cover is attached to the lower housing for defining a second receiving space (611) therebetween. The actuator has a bracket (41) connecting with the elastic ring via the channel and an actuating portion (42) extending from the bracket towards the bottom cover. The terminal plate, the moveable electrode plate, the insulative layer, and the fixed electrode plate are positioned along an upper-and-lower direction and received in the second receiving space.

Abstract: A push-button assembly for a gaming terminal is operative to actuate a switch or other actuator. The push-button assembly includes a plunger extending into a bezel to actuate the switch. The push-button assembly further includes a bifurcated gasket, having a positioning band that bifurcates into two diverging arms, positioned between a plunger sealing perimeter and a bezel rim so that, while the plunger moves between an extended position and a retracted position, the bifurcated gasket continuously contacts the plunger sealing perimeter and the bezel rim.

Abstract: A switch operator is provided that includes a single piece actuator shaft coupled to a single piece cap. According to certain embodiments, the actuator shaft may be snap fit to the cap. The cap may include an annular sleeve and an annular skirt that extend orthogonally from the cap. The sleeve includes recesses that receive tabs of the actuator shaft to couple the actuator shaft to the cap. In certain embodiments, the actuator shaft may include slots that allow the actuator shaft to flex upon attachment to from the cap. A bushing encircles the actuator shaft and extends into the cap where the bushing is disposed between the annular sleeve and a skirt. The actuator shaft also includes a pair of diametrically opposed slots that house a detent assembly. The detent assembly may be employed to retain the switch operator in the actuated position and in the unactuated position.

Abstract: A push-button assembly has a button retainer having a first side wall connected to a second side wall, with an included angle between the first and second side wall being in the range of about 100 degrees to about 170 degrees. Additional side walls connect the second side wall back to the first side wall, forming a hollow portion within the button retainer. The button retainer can be mated within the channel of a corresponding bezel structure. The bezel structure can be tuned to fit the button retainer along a single axis of the bezel structure. A tune-to-fit process includes forming the bezel structure from a mold and measuring the fit of the button retainer within the bezel structure along an x-axis. The bezel mold is either re-cut or material is added to the bezel mold along the x-axis, without re-cutting or adding material along any other axis.

Abstract: An actuating element for controlling an electronic device is providing. The actuating element including a front cover having an actuating surface to be actuated by a user and a support structure adapted to be coupled to the front cover. The support structure having guiding rips that guide the movement of the actuating element in a housing upon actuation of the actuating element. The front cover having centering shoulders that contact the guiding rips for positioning the support structure relative to the front cover when the front cover is coupled to the support structure.

Abstract: A thin-type keycap structure comprising a key cap layer and a plastic film on the upper surface of the key cap layer. The thin-type keycap structure and the metal dome on a PCB are assembled to form a keypad structure. The thin-type keycap structure is made through compression molding of the plastic film and a resin together. The surface of the plastic film may be embossed before the compression molding.

Abstract: An emblem-unified trunk opening and closing device may include a housing including an outer case and an inner case, wherein the outer case is attached to a stationary member and includes a guide hole and the inner case includes a guide passage, a knob attached to the outer case of the housing, wherein the knob includes an emblem configured to be movable through the guide hole of the outer case, a connector provided in the guide passage of the inner case and to which a terminal electrically contacting an outer electric source is set, a printed circuit board (“PCB”) disposed inside the guide passage of the inner case and configured to electrically contact the terminal, and a contact unit configured to selectively contact the PCB by actuation force of the emblem so as to apply an electric current to the terminal of the connector.

Abstract: A pushbutton for a hearing device is provided. The pushbutton includes a probe guided into a housing shell and includes a locking element. The locking element produces a first snap-on connection between the housing shell and the probe when inserted into the probe. As a result, the pushbutton is fixedly connected to the housing shell, as a result of which the housing shell can be easily exchanged.

Abstract: A waterproof push button switch does not need to be covered with a resin to a height at which a divided connected portion of a case for the switch is hidden by the resin in a height direction and the divided connected portion may be waterproofed. A gap (55, 57) is formed between a peripheral wall portion 7b of a base case 7 and a second cylindrical wall portion 9b of a cover case 9, and between an opposite surface 41 of the cover case 9 and a waterproofing seal member 11. The gap (55, 57) extends from an opening portion of the base case fitting chamber 37 to an annular watertight seal portion 51 to completely surround a periphery of the watertight seal portion 51. The thickness of the gap portion 55 is determined so that the resin entered into the gap portion 55 from an opening portion 37a of the base case fitting chamber 37 reaches the watertight seal portion 51 by surface tension.

Abstract: A press switch is composed of a base, a light-emitting device, a housing, a movable seat, and a pressing element. Due to the flat surfaces of the base and the ribs of the movable seat, the area of contact between the base and the movable seat is reduced. In addition, due to the ribs of the movable seat and the flat surfaces of the housing, the area of contact between the movable seat and the housing is also reduced. These reduced areas of contact allow the pressing element to be pressed stably and smoothly.

Abstract: A push-button assembly for a handheld radio (100) is provided which permits off-axis actuation by a gloved user amongst a crowded radio control environment. The push-button (108) includes first and second guide posts (202, 204) of different length, one guide post also serving as a switch actuator. An alignment guide (206) receives the two guide posts (202, 204). The alignment guide (206) with the first and second guide posts (202, 204) are coupled within a recessed portion (216) of a housing (102) to provide tactile feedback, even during gloved usage. The alignment guide (206) may further provide a light guide (110) which can operate as a third guide post for the radio (100).

Abstract: A push switch includes a housing having a top opening and a recessed section at a lower part, a push-type switch contact placed on an inner bottom face of the recessed section, an operating unit having an operating section at an upper part and a flange section at a lower part, a resilient unit placed under the operating unit in the recessed section for energizing the operating unit upward, and a cover for covering the top opening and having a center hole from which the operating section extends upward. The operating unit is movable vertically guided by a guide projection placed on inner walls confronting each other of the recessed section and extending vertically and by a concave section formed on the flange section for mating with the guide projection. The operating section includes faces vertically rising from the positions where the concave sections are recessed most inward.

Abstract: A keyboard includes a plurality of keys. Each key includes a base, a key cap detachably connected to the base and includes at least two conductors, a flexible element connected between the key cap and the base, and a plurality of conduct lines mounted on the base. The conduct lines are not contacting each other. One end of each conduct line is connected to a processing unit. Each conduct line is assigned a code. If the key cap of one key is pressed, the conductors of the key contacts the conduct lines, thereby creating an electrical connection between the two conduct lines, and generating an electrical signal. The processing unit determines the function of the key according to the codes of the connected conduct lines.

Abstract: A push switch includes an operating slider, an actuator with a sliding member, a return spring, a housing, a main body in which the operating slider, the actuator, and the return spring are supported by the housing, a heart cam mechanism (including an engagement pin and a cam groove) incorporated in the main body, an operating knob which caps the operating slider, and a fixed contact provided for a circuit board such that the sliding member is allowed to be brought into contact with and separated from the fixed contact. When the operating slider is moved upward or downward, the actuator is driven to be laterally slid. The housing is snap-fitted to an outer casing (upper casing) holding the circuit board. A space is provided between the housing and the circuit board.

Abstract: A key module for a keyboard includes a key having a guiding plunger, and a key housing having a set of walls with an opening formed by the set of walls. The opening formed by the set of walls is configured to receive the guiding plunger. The set of walls includes at least eight guiding surfaces configured to contact the guiding plunger. The guiding plunger is configured to contact the eight guiding surfaces as the guiding plunger moves up and down in the opening.

Abstract: An electronic device includes a housing, a button plate, a support element and a printed circuit board. The housing has an opening. The button plate is disposed at the opening of the housing, has a central region and two sides, wherein the button plate is mounted to the housing through the two ends of the two sides formed by elastic arms respectively. The support element is disposed under the central region of the button plate for defining the button plate into left and right parts. The printed circuit board is located underneath the support element, has two switches located respectively corresponds to the left and right parts of the button plate.

Abstract: A keyboard includes a keyboard unit and casing. The keyboard unit is rectangular and includes a first and second surface, the first surface including at least one key disposed thereon, the second surface including a protrusion portion that protrudes therefrom. The protrusion portion includes an engagement hole open toward a first direction that corresponds to a longitudinal direction of the rectangle. The casing includes a third surface on which the keyboard unit is mounted, the third surface including an insertion or through hole into which the protrusion portion is insertable, the casing including an engagement protrusion provided at a position opposed to the engagement hole of the protrusion portion that is inserted into the through hole, the engagement protrusion being engaged with the engagement hole of the inserted protrusion portion when the keyboard unit is moved in the first direction. A method of assembling the keyboard is also described.

Abstract: A keypad includes at least one push-button switch and a key to operate the switch along a translational axis. The geometric dispersions of the keypad are accounted for, to the lengthening of the travel of the key and to the enhancement of the tactile sensation when the key is pressed to operate the switch. The keypad includes a plunger, interposed between the key and the switch, of which a stiffness along the translational axis increases continuously with an increase in the compression of the plunger. A slight stiffness at the beginning of compression allows a long travel of the key, while a greater stiffness at the end of compression gives a good tactile sensation with an assured contact even when there are off-center pressures on the key.