Abstract: A tamper resistant membrane switch includes a backer plate and an overlying metal panel. Sandwiched between the backer plate and metal panel is a membrane switch subassembly. A plurality of spacers between the backer plate and metal panel separate the two but allow the metal panel to deflect toward the backer plate when external finger pressure is applied. Such deflection closes the underlying poles of the membrane switch subassembly to actuate the switch. The positioning and size of the spacers determines where deflection can occur and how much force is needed to actuate the switches. The overlying panel, being formed of solid metal over its entire surface, is resistant to damage from vandalism, thievery or other attack.

Abstract: A selecting switch operating section provided to support movable contact points includes circular elastic support walls disposed along an arrangement circle of selecting stationary contact points, and a pushing portion. When the selecting switch operating section is pushed by an operating portion tilted integrally with the operating lever, at least one of movable contact points comes into contact with at least one of the selecting stationary contact points. Thus, it is not necessary to provide accommodation space for other members between the adjacent selecting stationary contact points. Also, it is possible to reduce the spacing interval between adjacent selecting stationary contact points in the arrangement circle, so that the diameter of the arrangement circle can be reduced and the entire lever switch can be reduced in size.

Abstract: A switching field for electromechanically switching electrical signal lines with crosspoints. The parts forming the crosspoints comprising membranes, at and between which further parts of the circuit are disposed. The switching field is particularly for communication and data transfer applications. The cross points are disposed matrix-shaped manner and signal lines assigned to the individual crosspoints. The crosspoints are composed of at least two contact surfaces which are movable relative to each other, to the one contact surface, a permanent magnet, and to the other contact surface, a ferromagnetic material with a coil assigned thereto.

Abstract: A button system for the control panel of an automotive audio system is adapted to curved bezel shapes wherein push buttons are non-coplanar. Each button operates normal to the bezel surface at the button location. The button system interfaces with a flat elastomeric membrane switch pad.

Abstract: A horn switch support plate for use with a membrane horn switch as part of a horn switch assembly for insertion into a horn switch pocket of a driver side airbag module. The horn switch support plate includes a generally flat, rigid base supporting the horn switch. A substantially continuous peripheral wall extends upwardly from the base, and peripherally encircles the membrane horn switch. The height of the peripheral wall is sized to be greater than the thickness of the horn switch to ensure that the horn switch will not be compressed prior to actuation by a vehicle driver. The horn switch support plate also includes four tabs extending inwardly from and generally perpendicular to four corners of the peripheral wall, each tab extending over, respectively, a corner of the horn switch to retain the horn switch within the horn switch support plate.

Abstract: A keyboard or keypad assembly has an outer housing of rigid material with an upper panel having a single opening or plural key receiving openings, and a keypad of resilient material located beneath the upper panel, with keys projecting upwardly from the keypad through the panel. A printed circuit board is positioned in the housing beneath the keypad and is secured to the upper panel with the keypad sandwiched between the panel and circuit board. The keypad has a peripheral rim surrounding the key containing area, and an upwardly facing groove is located in the rim. A corresponding, downwardly projecting rib is provided on the upper panel for seating in the groove to form a moisture seal by compressing the resilient material at the base of the groove, so that spilled liquids cannot enter the area in which the circuit board is located via the openings in the upper panel.

Abstract: A pair of electrical contacts are provided on a lower surface of each key in a keypad assembly. When a key is depressed, the contacts are brought into electrical communication with a common conductive surface such that an electrical circuit is completed between a discrete pair of terminals. The arrangement, number, and configuration of keys can be changed without modifying the decoding logic and supporting circuitry of a keypad-operated instrument.

Abstract: A keypad configuration for an electronic device has a housing (180) with one or more push buttons (110) having centers (113), a maximum radius (115), and a maximum height (215). A specific area (118) surrounds each push button and has a minimum radius (129) that is at least five times as long as the maximum radius of the push button or at least three times as long as the maximum height of the push button. No additional push buttons are within this specific area. The size, height, and spacing of the push buttons provide a point contact sensation to a user's fingertip, which prevents a user from pressing more than one key at a time and provides space for alphanumeric labels beside each push button. This keypad configuration is particularly suited for portable electronic devices where a small keypad is desirable, such as cellular telephones.

Abstract: A frame component for a notebook computer wherein the frame component has tapered (e.g., conical) depressions that receive protrusions from printed circuit boards mounted adjacent the frame component. The tapered depressions are formed during plastic injection molding of the frame component by a tapered (e.g., conical) protrusion in the interior cavity of the mold. The tapered protrusion in the mold facilitates flow of molten plastic through a region between the apex of the protrusion and an inner surface of the mold which allows for smaller tolerances between the apex of the tapered depression and the bottom surface of the frame component. This results in an overall reduction in the thickness of the frame component from on the order of 3-4 mm to on the order of 1.5 mm. The tolerance between the bottom of the depression configured to receive the protrusion from the printed circuit board is on the order of 0.3-0.4 mm.

Abstract: An improved membrane switch includes multiple detents. A pair of electric circuits are completed by the membrane switch, and a pair of flexing portions are located on said membrane. A first flexing portion is overcome by a first lower insertion force to allow a first circuit to be complete, and a second flexing portion is only overcome by further insertion force. The second flexing portion is eventually overcome and completes a second circuit. The inventive membrane switch provides the operator with a clear indication and a detent feel for each of the two circuits.

Abstract: Portable electronic devices, such as notebook computers, are provided with the capability of a low profile and light weight keyboard, allowing greater reduction in the size and weight of portable computers without compromising the functionality. In specific embodiments, the present invention provides laptops, notebooks, and sub-notebooks with a low profile keyboard having a polymer top surface. In an embodiment of the invention, a structural rib 214 surrounds at least some portion of the key to advantageously provide a firm offset of the key top from the circuit board 206 for increased key travel over prior art designs. In another embodiment of the present invention, the keyboard key includes alignment pistons 218 affixed to the flexible key layer 202 and extend into holes in the circuit board 206 to provide advantages such as keeping the key's top surface flat, preventing the key from tilting or collapsing on only one or two sides.

Abstract: The switch actuator provided comprises a rubber dome, a housing, a keytop and a plunger. The rubber dome is seated on the switch and is selectively deformed to actuate the switch. The housing receives the rubber dome therein and has an upper opening defining an edge of the opening and has an inner surface. The plunger moves reciprocally within the housing and is guided by the edge during the reciprocal movement of the keytop. The keytop, which has a bottom surface, moves reciprocally and vertically together with the plunger to selectively deform the rubber dome to actuate the switch as the result of the operation of the user. The invention is characterized in that a slant surface is formed on the inner surface of the housing to retain the bifurcated hook end of the plunger to reduce the noise generated during movement of the plunger.

Abstract: For economy of molding and ease of assembly to a control panel, a one-piece cluster of push buttons arrayed in two rows includes hinges coupling groups of buttons. Each hinge is located at the intersection of four buttons and includes an arm extending from a corner of each button in a group. Each arm extends transverse to the plane of the cluster, and the four adjacent arms join to form an arch. Each arm is long and thin enough to be quite flexible for permitting each button to operate independently of the others.

Abstract: A key switch fabrication method including the steps of: i) molding a rubber pad from silicone resin, and making a rubber key stitch body from the rubber pad by stamping; ii) printing the desired letter or pattern on the top side (10) of the rubber key switch body (1) thus obtained, then drying the printed key switch body 1 by baking; iii) adhering a liquid silicone rubber on the key switch body over the printing thereof by spot glueing to form a transparent key cap; vi) heating the key switch thus obtained from step iii) in a baking oven at 60.degree. C. for 5 minutes and then heating it at 120.degree. C. for 10 minutes to harden the key cap; and v) examining the quality of the finished key pad.

Abstract: An appliance control panel having selective backlighting includes a selection area that is normally visible to the operator including an "OPTIONS" switch. By pressing the "OPTIONS" switch, a plurality of lamps are illuminated. The light from the lamps passes through an assembly of overlays and illuminates a set of optional switches that are not normally visible. The incandescent lamps are positioned partially within a clear plastic mounting plate with a lamp on each side of the optional switches. The clear mounting plate is masked on both sides except for areas on the plate that form depressions around each optional switch. The light is trapped between the masks and escapes through the overlay assembly, illuminating the optional switches.

Abstract: An electrical switch is described which comprises a housing, an operating member mounted on the housing for movement from a rest position in at least three directions relative to the housing, and at least three sets of electrical contacts, a respective set of contacts being operable by movement of said operating member away from the rest position in a respective one of said three directions. Each of the sets of contacts comprises a fixed contact and a movable contact, each of the movable contacts being carried by a common resilient annulus.

Abstract: A continuous linear contact switch is provided. The continuous linear contact switch includes first and second resilient strips, each having first and second longitudinal edges, an outer surface and an inner surface. The respective first and second longitudinal edges of the first and second resilient strips are joined to each other at first and second seams along an entire longitudinal length thereof. Beads are located along the seams on the inner surfaces of the first resilient strip so that the first resilient strip remains generally flat and the second resilient strip is arched to form an inner cavity between the generally flat first resilient strip and the arched second resilient strip. A first flexible, electrically conductive strip is located on the inner surface of the first resilient strip. A second flexible, electrically conductive strip is located along the inner surface of the second resilient strip, spaced from the first flexible, electrically conductive strip.

Abstract: A two-stage movement seesaw switch apparatus of the light irradiation type which is compact and superior in operation feeling. The two-stage movement seesaw switch includes a pair of operation plates disposed immediately below a manually operable knob. Two sets of push switches, each set including two push switches, are disposed such that a straight line interconnecting the push switches of each set extends obliquely with respect to a center axis of pivotal motion of the manually operable knob. The push switches are actuated by contact with the operation plates when the manually actuated knob is pivoted. Each of the operation plates has an opening formed therein for passing light emitted from an LED therethrough and has a pair of projections formed thereon next to the opening.

Abstract: A computer keyboard 10 has a plurality of keys 24 with each key 24 having a membrane keyswitch 30. Each keyswitch 30 has a lower membrane layer 32 with a printed circuit having switch contacts 42 printed on an upper side thereon within a switch contact area. An upper membrane layer 36 is provided having a printed circuit thereon with switch contacts 46 printed on a lower side thereon within the switch contact area and in actuation alignment with switch contacts 42. Dielectric pads 50 are printed over parts of the switch contact area forming dielectric mounds between switch contact segments. Stress concentration pads 54 are printed on the upper side of the upper layer 36 spaced intermediate the dielectric pads 54 for causing the upper layer 36 to deflect between the dielectric pads 50 to bring portions of the switch contacts 46 into contact with the switch contacts 42.

Abstract: A notebook computer is provided with a collapsible keyboard structure in which the keys are vertically moveable, toward and away from an underlying key support structure, through a stroke distance. Each key has an upper return spring member secured to and depending therefrom, and overlies a lower return spring member secured to a signal pad structure that underlies the key support structure and is horizontally shiftable relative thereto. As each key is manually depressed through its stroke distance its associated separate upper and lower return spring members cooperate in series to resiliently resist the downward movement of the key through its entire stroke distance, and also function to return the key to its upwardly extended pre-stroke position. In response to a horizontal shifting of the signal pad structure relative to the key support structure, each key is driven downwardly to a retracted storage and transport orientation thereof.

Abstract: A multi-switch membrane-switch assembly includes a longitudinally extending, resiliently flexible, non-conductive membrane having a convexly bowed cross section defining on an undersurface thereof a plurality of interrupted circuits defining longitudinally aligned pairs of laterally spaced, conductive contacts. A rigid substrate defines on an oversurface thereof a plurality of longitudinally aligned, conductive shorting elements. A laterally spaced pair of longitudinally extending, non-conductive positioning ribs are disposed on the oversurface of the rigid substrate. Each positioning rib defines an undercut for receiving and maintaining a longitudinally extending edge of the membrane, the positioning ribs cooperating to maintain the membrane convexly bowed.

Abstract: An electrical switch having a plurality of plungers (6) and (8) telescoped one inside another. Each plunger is depressable from an extended position independently of the other(s) against a bias provided by a spring (28, 46) to operate respective switch contacts (62, 56).

Abstract: An improvement of a push button switch is provided. The improvement is characterized in that the plunger has a cross section of polygon form which contacts with the inner surface of the housing at a plurality of contact lines and a small segment of guiding surface is provided between the hook and bottom surface of the plunger for more accurate insertion of the plunger into the vertical slot of the housing.

Abstract: A reconfigurable keyboard includes at least two key switches which each has a plunger housing projecting from a top surface thereof, and a multi-switch key cap engageable with the key switch and having at least one dimension that is sufficient to span the at least two key switches. The key cap includes one active switch post to which a plunger is attached, the plunger being reciprocally movable in the plunger housing of one key switch for actuating the key switch when the key cap is depressed, and at least one passive switch post which is also reciprocally movable in the plunger housing of another key switch without actuating the switch when the key cap is depressed. The key cap is selectively positionable anywhere on the keyboard in either a horizontal or a vertical direction. Each key switch further includes four openings each of which are located in a corner of the top surface of the key switch.

Abstract: In a rubber contact switch in which ends of lead lines of an LED extend to the rear surface of a printed board through holes of a rubber contact sheet to be soldered on the printed board, a recessed portion is formed in the peripheral portions of the holes on the rear surface of the rubber contact sheet, and heat generated by soldering of the lead lines is prevented from being directly transmitted to the rubber contact sheet.

Abstract: An inside case made of rubber is mounted in an outside case, a substrate integrally provided with an engine stop switch circuit and a switch electrode of an engine stop switch unit is assembled in the inside case, and its lower side is filled with curable insulating base material to be sealed. Further, a switch contact opposed to the switch electrode is formed of pressure sensitive conductive rubber, and a reversal spring is further interposed on the pressure sensitive conductive rubber. As a result, wirings are eliminated, a decrease in the size of the entire apparatus and simplification can be realized, and a metal contact is eliminated to improve durability.

Abstract: A universal remote commander provided as a replacement for an original remote control unit has a specialized shape, which is intended to be easily held and gripped in the hand, employs only a minimum number of controls that are used in conjunction with a function selection switch that selects either television, VCR, or cable, for example. The specialized housing is V-shaped in orthogonal cross sections so that it is wider at the top than at the bottom in the front view, whereas it is narrower at the top and wider at the bottom in the side view so as to achieve a generally cylindrical feel when held in the hand. A rotary knob can be employed at the bottom of the housing to act as the function selector switch or the rotary knob can be spring loaded and to act as a jog switch when controlling a VCR. A keypad can include translucent buttons that can be lit from inside the remote commander for use in dimly lighted rooms.

Abstract: A track ball mechanism is mounted on a cantilevered portion of a printed circuit board that is supported in a housing. A switch, mounted on the opposite side of the cantilevered portion of the printed circuit board, is operated when it engages a boss on the housing. The ball of the track ball mechanism is operated by a human digit in the usual manner and the switch is operated when pressure on the ball deflects the cantilevered portion of the printed circuit board which causes the switch to engage the boss. The boss is supported on a cantilevered portion of the housing which deflects under excessive loading to protect the switch and track ball mechanism.

Abstract: A flexible or roll-up electronic keyboard is provided for use with electronic devices. The keyboard is formed with a plurality of section of flexible plastic materials and embodies a dual-walled bottom which includes a network of support members which can be inflatable to provide a rigidity to the structure of the keyboard sufficient to prevent false signals. At least one separately inflatable accordion-pleated wedge means is also provided to enable variable adjustment of the plane or planes of the keyboard relative to the hands of its operator, sufficient to reduce the risk of nerve disorders such as carpal tunnel syndrome in the operator.

Abstract: A keyboard for a fully electronic, microcomputer-controlled commercial scale with call-up memory, in particular for self-service or quick-service purposes, comprises a keyboard consisting of a plurality of individual keys with actuating elements, whereby symbols and/or alphanumerical characters are assigned to the individual keys. The keyboard has a guide plate with a plurality of individual keys arranged at a certain grid distance from each other. The guide plate is provided over its entire surface with actuating elements for the individual keys.

Abstract: A suspend (sleep) switch for a portable electronic device, such as a notebook computer, is mounted on a printed circuit board. The suspend switch includes a first contact which is positioned in juxtaposed relationship with a second contact. The contacts are formed from an electrically conductive metal or other electrically conductive material which is sufficiently resilient to support an actuator and to hold the two contacts apart in normal operation. In addition, the resiliency of the two contacts allows the two contacts to adjust to different distances between the printed circuit boards on which the contacts are mounted and the cover of the electronic device which constrains the actuator. When the cover of the electronic device is closed, the actuator pushes the two contacts into electrical contact, preferably with a wiping motion, to provide an electrical connection which can be sensed by circuitry on the printed circuit board.

Abstract: A keyboard having an array of non-planar keys and a method for manufacturing such a keyboard is provided. In one embodiment, the non-planar array is a double-convex array. Electrical connection along the keys and/or from the keys to associated electronics is provided by way of a circuit board. The circuit board has a geometry and flexibility which permits the circuit board to conform to a shape which is non-planar along two non-parallel axes. In one embodiment, the circuit board can be configured in a double-concave shape. The circuit board includes one or more slots defining two or more projections. These projections can be placed in a configured non-coplanar configuration along a first axis and the circuit board can be flexed to a non-planar configuration along a second non-parallel axis.

Abstract: A notebook computer is provided with a collapsible keyboard structure having keys supported on scissored linkage arm assemblies in which, in response to closing of the computer housing lid, key return spring portions of the keyboard are shifted away from their normal underlying relationships with the keys, and the scissored linkage arm assemblies and keys are permitted to retract to a storage/transport orientation in which the overall thickness of the keyboard structure is reduced by an amount essentially equal to the stroke distance of the keys. When the lid is subsequently opened, the key return spring portions are shifted back to their normal underlying relationships with the keys, and the keys and scissored linkage arm assemblies are forced outwardly by the return spring portions to their extended, operative orientations above the return spring portions.

Abstract: A low profile membrane switch adapted for use over an automobile steering wheel airbag assembly for actuating a horn. The low profile membrane switch is comprised of an opposing pair of flexible electrodes separated by a dielectric layer. The dielectric layer has a unique pattern defining opposing electrode contact portions. A plurality of integral outwardly-extending protrusions are screen printed on the exterior surface of each flexible electrode, one over each of the opposing contact portions. These protrusions help concentrate an applied force to bring the respective electrode contact portions together to make electrical contact with the other. The opposing contact portions are defined by the dielectric pattern, and have a high density to insure redundancy and closure of the switch when one depresses the membrane switch with one's hand, and to insure the switch does not inadvertently close when flexed.

Abstract: A keypad structure includes a printed circuit board with a plurality of miniature push-button switches mounted thereon in a predetermined array with the operating surfaces of the buttons substantially in a common plane. An array of holes is formed in a layer material termed a spacer member which is releasably secured to the pcb with the wall defining each hole surrounding a corresponding switch. A plurality of openings is formed in a template sheet which is adhesively secured to the spacer member. The openings in the template sheet are of larger diameter than the holes in the spacer member and provide a positioning guide for dome-type spring members which are supported on the spacer member and overlie the respective operating surfaces of the switch buttons. A flexible, outer sheet is adhesively secured to the outer surface of the template sheet, capturing the springs between the spacer member and the outer sheet.

Abstract: A user configurable control device is particularly suitable for household devices such as remote control transmitters. A variety of function control elements in the form of keys are provided to the consumer who selects a desired set of the control elements. Each of the control elements has a unique pattern of projections molded into the bottom surface. These projections are in operative alignment with an array of membrane switches disposed on a switching substrate within the control device. The control device includes a front panel that is perforated with a pattern of slots. Each of the control elements has a pair of projecting tabs that lock the element onto the control panel so that it is securely retained thereon, but may be released if desired. The projections on the bottom of the element extend through the slots in the front panel to the switching substrate below.

Abstract: A control panel includes controllers in the form of push buttons supported by an elastomeric switch pad over an electroluminescent lamp panel. The electroluminescent panel includes circuits formed by chargeable areas which register with optical indicia carried by the buttons and transmitted through openings in the elastomeric layer. The elastomeric layer includes pads which resiliently urge the buttons to a rest position at which contacts carried by the elastomeric pad are spaced apart from terminal conductors on a printed wiring board. A peripheral wall of the pad formed with the elastomeric layer is supported by a tactile membrane which permits depression of the button to engage the contact against the terminal conductors of the printed wiring board, and returning the button to the rest position.

Abstract: A retractable key assembly comprising a key top and an externally extending pivot arm. The pivot arm allows arcuate movement of the key top about a pivot axis such that the key top can be used in an upper, active keying position or stored in a lower, inactive position. The use of a pivot arm enables a lower profile keyboard when the keyboard is in the retracted, inactive position. Displacement of the internal actuation assembly allows the keytop to actually rest on the keyboard base. A translatable base member is useful to raise or retract the key assembly. The disclosed key assembly provides an aesthetic appearance and improved keying accuracy, relative to conventional keyboard arrangements.

Abstract: A membrane switch with multiple switch sites in which, at a given switch site, three concavo-convex structures are juxtaposed over a set of switch contacts so that when the key is pressed, the force applied causes the three structures to cooperate to complete an electrical circuit and close the switch. An operator easily can detect when a switch has been effectively closed because of the superior tactile response resulting from the concavo-convex components. Apertured spacers also are provided to allow the contacts to be brought into communication with each other and to provide a distance through which the actuating force must travel to further enhance tactile feedback to the user.

Abstract: A microwave oven has a cooking time selecting unit and a cooking power selecting unit. The cooking time selecting unit has a first shaft which extends through a control panel and a first knob is mounted on the first shaft. The cooking power selecting unit has a second shaft which is disposed parallel to the first shaft and extends through the control panel. A second knob is mounted on the first shaft and has an outwardly open recess in which the first knob is freely rotatably disposed. A rotary power transmitter such as an idler gear or a timing belt interconnects the second knob and second shaft.

Abstract: An electronic device (100) has a housing (110), and a shielded keypad interface (150) for actuating a switch (285, 290) accessible through an opening (115) within the housing (110). The keypad interface (150) has a key surface (265) that is aligned with the opening (115) and with the switch (285, 290). A conductive layer (250) between the key surface (265) and the switch (285, 290) covers the opening (115). The conductive layer (250) is electrically isolated from the switch (285, 290), and coupled to electrical ground (255) to provide an electrical shield for the keypad interface (150).

Abstract: A low cost, highly sensitive tactile pointing device includes a planar substrate, an insulating spacer about a periphery of the substrate, and a planar cover. The cover in an active area carries an electrically conductive film designed to contact a conductive film carried upon an active area of the substrate. An insulating spacer and conductive dot are also located at some point within the active area to form a non-contacting rest area. Appropriate forces applied in a direction normal to the plane of the substrate or cover cause deflection, leading to contact between the cover and the substrate. The point of contact identifies intent, direction and magnitude.

Abstract: A tilting member has a force bearing portion to which operating force is applied, and a supported surface. A supporting member has a supporting projection with which the supported surface of the tilting member may come in contact. When the operating force is applied to the tilting member, the tilting member tilts with respect to the supporting member. The supporting member supports the tilting member at a supporting point where the supporting projection of the supporting member is in contact with the supported surface of the tilting member, about which supporting point the tilting member tilts. The tilting of the tilting member, with respect to the supporting member, establishes a predetermined electrical contact.

Abstract: A low-profile keyboard (5) each switch (3) having a dished keybutton (3) held upward by a rubber dome (49) and having ribs (55) which depress extension (43 and 31) which carry electrical traces (45 and 33) to activate the switch. The assembly is mounted on post (15). A lower recess (21) permits excess travel to a quiet stop. The rubber sheet (47) provides spill resistance.

Abstract: A n-key rollover keyboard having an application specific integrated circuit (ASIC) with a large number of pins, each pin directly connected to a key contact, with the other side of the key contact connected to ground. The direct wire arrangement allows use of a single sided circuit board. The keyboard has a reduced cost over prior n-key rollover designs by allowing removal of the series diodes and double sided circuit board.

Abstract: An illuminated elastomeric keypad switch assembly has an optical conductor on which a printed circuit is printed via electrically conductive ink and a keypad provided with translucent areas for passage of light. The optical conductor has recesses located adjacent the key caps whose width and depth progressively increases proceeding from the closest to the farthest key cap from a light source so that a uniform amount of light is transmitted through the key caps.

Abstract: A keyboard for a computer includes a rubber pad having conductive rubber cones and a recessed portion, a key unit having keys respectively disposed above the rubber cones, an upper silver grating and a bottom silver grating and retained between a frame and the rubber pad and having projecting strips with respective electric contacts projecting into the recessed portion and in contact with a circuit board mounted within the recessed portion.

Abstract: A keyboard circuit apparatus is constituted such that resistive elements are provided both in a first sheet and a second sheet, an insulating spacer being laid on the first sheet, and the second sheet being laid on the insulating spacer. When a key switch is closed, one of the resistive elements provided on the first sheet and one of the resistive elements provided on the second sheet are electrically connected in series so that a desired value of resistance can be obtained.

Abstract: The top side wall of a portable computer base housing portion has a rectangular opening therein that complementarily receives a keyboard assembly. The keyboard assembly has a rear side edge portion from which a spaced plurality of mounting tabs outwardly project, and a spaced plurality of latch structures are captively retained on a front side edge portion of the keyboard assembly. Each latch structure includes a tab member that is slidable relative to the balance of the keyboard assembly between a forwardly extended position and a rearwardly retracted position, and a cap portion pivotally retained on the tab member.

Abstract: A switching apparatus which includes a rubber keypad (32, FIG. 2) with a rubber cap (36) that can be depressed by a person's finger to snap a snap dome (52) that connects contacts (21, 22) of a first switch (70), provides increased tactile feedback to the person's finger. A keycap (42) of rigid material includes a cover (44) lying on top of the rubber cap and also includes a stem (54) that projects down through a hole in the cap, with a lower stem end (60) lying above the snap dome to snap down the dome when a person's finger depresses the cover. The tactile snap feedback is transmitted directly through the rigid material of the stem to the rigid material of the cover, to the person's finger to indicate that the switch has been closed. The cap has a radially outer part (84), and an electrically conductive element (82) is mounted on the outer part to engage contacts (23, 24) of a second switch (80) to close it, before the snap dome is snapped to close the first switch.