US3742157A

US3742157A - Keyboard switch assembly with improved movable contact

Info

Publication number: US3742157A
Application number: US00134715A
Authority: US
Inventors: W Leposavic
Original assignee: LEMATEX Inc
Current assignee: Magna Donnelly Corp; LEMATEX Inc
Priority date: 1969-09-25
Filing date: 1971-04-16
Publication date: 1973-06-26
Anticipated expiration: 1990-06-26
Also published as: GB1318409A; DE2046612A1; FR2130817A5; US3600528A

Abstract

A multiple switch construction for a keyboard or the like produced as a flat panel embodying laminates of electrical conductors in desired patterns, assembled as stratifications in close proximity and separated by spacers. Individual depressible means operating through resilient members urge movable switch elements into contact with fixed electrical conductors with a rotary, wiping action to insure positive electrical contact.

Description

United States Patent 1191 Leposavic 1 June 26, 1973 KEYBOARD SWITCH ASSEMBLY WITH IMPROVED MOVABLE CONTACT [75] Inventor: Wayne V. Leposavic, Saratoga, Calif. [73] Assignee: Lematex, Inc., Santa Clara, Calif.

[22] Filed: Apr. 16, 1971 21 Appl. No.2 134,715

Related US. Application Data [63] Continuation-impart of Ser. No. 860,861, Sept. 25,

1969, Pat. No. 3,600,528.

[52] US. Cl 200/5 A, 200/159 B, 200/166 BH [51] Int. Cl. H0lh 9/26 [58] Field of Search 200/5 A, 159 B, 166 BH,

200/6 R, 8 A, 16 D, l R

[56] References Cited UNITED STATES PATENTS 3,261,928 7/1966 Schlesinger, Jr 200/8 A 3,594,684 7/1971 Miller 200/159 B X 3,324,432 6/1967 Ridler 200/166 311 X 3,240,885 3/1966 Grunfelder et a1. 200/5 A 3,290,439 12/1966 Willcox et a1 200/5 A X 3,591,749 7/1971 Comstock 200/159 B X 1,198,340 9/1916 Garretson 200/166 Bl-l UX 3,600,528 8/1971 Leposavic 200/5 A Primary -Examiner-J. R. Scott Attorney-Price, Heneveld, Huizenga & Cooper [57] ABSTRACT A multiple switch construction for a keyboard or the like produced as a flat panel embodying laminates of electrical conductors in desired patterns, assembled as stratifications in close proximity and separated by spacers. Individual depressible means operating through resilient members urge movable switch elements into contact with fixed electrical conductors with a rotary, wiping action to insure positive electrical contact.

18 Claims, 12 Drawing Figures sum 1 or 3 PATENIED JUHZ 8 1973 PAIENIEDJms 191a 3.742.157

sum

2 or 3 INVENTOR.

WAYNE V. LEPOSAVIC ATTORNEYS PATENTEDJUHZS I973 3.742.157

sum a nr 3 INVENTOR.

WAYNE v. LEPOSAVIC BY %w, M

ATTORNEYS KEYBOARD SWITCH ASSEMBLY WITII IMPROVED MOVABLE CONTACT This is a continuation-in-part of my copending application, Ser. No. 860,861 now U.S. Pat. No. 3,600,528, issued Aug. 17, 1971, filed Sept. 25, 1969, entitled MULTIPLE SWITCH CONSTRUCTION.

BACKGROUND This invention relates to multiple switches in a single keyboard and the like and more particularly to the provision of momentary switches in large blocks as distinguished from numerous independent switches assembled into a common block or unit.

Heretofore, most conventional momentary switches of the push button type have been produced as individual units. Normally, such individual switches include a plunger which when depressed will either mechanically engage or magnetically energize a pair of contacts to close an electrical circuit. In some cases a plunger carriers a magnet for shifting the latter into a position to excite or energize an active element to effect a sensor used in a remaining circuit as an indication of closed contact. Such momentary switches of the prior art are not conductive to close proximity of finger tab push buttons as in a keyboard or the like. This is so because the mounting of individual switches, leverages, and sensors in close relation becomes a tedious and time consuming task often fraught with error and faulty connections when later tested. In some applications such as computer keyboards, electric typewriters, and the like, the output currents from individual switches have to be understood by the remaining circuits. Such encoding usually requires solid state elements such as diodes, transistors, and/or integrated circuits.

Further, prior art switches have experienced difficulty in not making a good contact and/or encountering bounce so as to create different signals than those intended by the operator. In other words, the switches do not reflect the proper signal as each key is depressed because the movable contact does not make good contact with the stationary contact or it bounces" to make several repetitive improper signals rather than a signal which is desired for each depression of a key.

THE PRESENT INVENTION In accordance with the present invention I provide momentary type switches in large blocks arranged in various configurations and patterns. This contemplates producing such multiple switches by photography and chemical milling or metal etching processes.

I also produce multiple switches by the use of printed circuits on base blocks coordinated with gang contacts produced as metal stampings, chemical milling, or the like in such a manner as to require little or no tooling and a minimum of labor in assembly.

It is a further object to provide a relatively simple and compact multiple switch assembly with components assembled seriatim over a flat base block to thereby minimize cost in both assembly and manufacture. In this connection it is contemplated that the components of the multiple switches can be formed in any design or configuration of a keyboard or switch panel as desired superimposed one above the other whereby upon assembly of such components complete switching means is achieved.

It is yet another object to mass produce multiple switch panels by laminates of electrical conductors statified in close proximity for operation of each individual switch upon finger pressure applied thereto. In this connection it is contemplated that the laminates be spaced by dividers beneath individual push buttons or keys having indicia locating and/or identifying the individual switch therebelow.

Also, in accordance with this invention is provided a movable switch contact element having a moment arm to impart a rotary wiping action thereto as the switch is depressed.

Also provided is a multiple switch construction having individual push buttons biased toward a first or open position by means of return springs formed as metal stampings or the like, requiring a minimum of labor in assembly.

In addition, the assembly minimizes bounce" by providing a flexible layer which in one embodiment has a plurality of air pockets to compensate for the inertia of the movable contact and prevent it from bouncing and producing undesirable signals.

With the foregoing objects in mind it will be understood that the multiple switches of the present invention contemplate a construction requiring a minimum of parts within a minimum of space, eliminating soldering and hand assembly of individual switches to thereby produce keyboards and switch panels with the greatest economy.

These and other objects and advantages of the present invention will become apparent from a reading of the following specification and accompanying drawings wherein:

FIG. 1 is a plan view of a keyboard embodying the multiple push button switches of the present invention;

FIG. 2 is an enlarged section through FIG. 1 taken along line 22 and showing a first embodiment of the present invention;

FIG. 3 is a fragmentary plan view of one embodiment of the flexible contact element;

FIG. 4 is a perspective view of the flexible contact element shown in FIG. 3;

FIG. 5 is an enlarged section similar to FIG. 2 showing the switch depressed to effect the switching function;

FIG. 6 is a fragmentary plan view of another embodiment of a flexible contact element;

FIG. 7 is a perspective view of the contact element shown in FIG. 6;

FIG. 8 is a sectional view like FIGS. 2 and 5 showing a preferred embodiment of the invention;

FIG. 9 is a fragmentary plan view-of the push button return spring utilized in connection with the preferred embodiment shown in FIG. 8;

FIG. 10 is a fragmentary plan view of a flexible contact element utilized in the preferred embodiment;

FIG. I 1 is a fragmentary view similar to FIG. 8 show ing a further modification of the preferred embodiment; and

FIG. 12 is a section through FIG. 2 taken along line 12-12 showing the fixed contact elements.

Referring to FIGS. 1, 2, 5, and 12, the first embodiment of the multiple switches of the present invention, as previously disclosed in U.S. Pat. No. 3,600,528, comprises a non-conductive base panel 20 having a photographically printed circuit etched on its surface to provide a plurality of fixed contact elements 22 thereon divided by a screen of spacers 24 into separate switch areas or zones 26. Each of the contact elements 22 have independent electrical connection to one side of an electrical circuit through a suitable plug arrangement 28 which may be formed on the base 20 for mat- I ing with a suitable jack (not shown). The fixed contact elements, illustrated in detail in FIG. 12, on the upper surface of the base panel 20 may be arranged in the form of a ring or segments thereof having an outline configuration compatible with the contact fingers 39 of the movable contact elements 30 located thereabove. In some applications, it is desirable to provide one fixed contact 23 in any given switch area 26 at a level slightly below the level of the remaining contacts. As the movable contacts are moved toward and away from the fixed contacts, the lower fixed contact is the last to make and the first to break the circuit and may be utilized in computer input devices as a control function. The movable contact elements 30 are preferably formed in a gang stamping 32 or chemically etched on a sheet of tempered beryllium copper or other material having a high degree of electrical conductivity. In the gang stamping 32 thus formed, the contact element for each switch unit is confined within a frame 34 which registers with the screen of spacers 24 on the base panel 20 for support above the fixed contact elements 22. The spacers 24 are shown constructed of conductive material but as shown do not conduct current since they rest on the insulated part of base panel 20 and are no part of the keyboard circuit. Within this frame 34, one or more legs 36 extend centrally inwardly to the movable contact element 30 to support the same in yieldable suspension above the fixed contact element in each switch cavity.

Two embodiments of the movable contact elements are illustrated in FIGS. 3, 4, 6 and 7. As they are similar in construction, like reference numerals will be utilized to designate like parts with the prime designation utilized to distinguish the embodiment of FIGS. 6 and 7.

As illustrated in FIGS. 3 and 4, the movable contact elements 30 are in the form of an annular flat ring 38 having spoke-like fingers 39 extending radially inward therefrom toward the center. In FIGS. 6 and 7, the movable contact element 30 is in the form of a solid flat center 38 from which a plurality of fingers 39' extend radially outward for yieldable contact with the fixed contact elements 22.

In either form of movable contact 30, as shown in FIGS. 3 and 4 or 30 as shown in FIGS. and 6, the spider-like legs 36 afford yieldable suspension thereto. For such legs 36 are preferable within each frame 34, each leg 36 having integral connection at its base end 40 to one side of the frame 34 adjacent one corner thereof. The legs 36 are separated from the adjacent right angled side of the frame and extend approximately half way across the square frame 34. Each leg 36 terminates in a hook-like bend 41 the extreme end 42 of which is integrally connected to the contact element 30 or 30' as the case may be. In the case of the spoked center element 38 of FIGS. 3 and 4, the extreme ends 42 terminate at approximately 90 from the corner of the frame 34 where the particular leg 36 is connected to the frame. In the case of the solid centered contact 38' of FIGS. 6 and 7 having spider-like fingers 39' for center type pressure, the extreme end 42 of each leg 36 terminates at approximately a full 180 relative to the corner of the frame 34 where the particular leg 36 is connected to the frame.

It is inherent in my copending application Ser. No. 860,861 that when downward pressure is applied against either the open center contact 38 or the solid center contact 38, the legs 36 associated therewith are flexed while the center contacts and their spokes or fingers move spirally downwardly perpendicular to the flat upper surface of the printed circuit, i.e., rotating while moving vertically within the switch zone 26 confining the same. In other words, the fingers 39 turn or rotate while moving downwardly within the switch zone 22. This rotating action is created by reason of the hinge-like flexing action of the legs 36 from one plane into another. As the annular flat ring-like member 38 on the inner ends of the legs 36 is depressed, the distance between the ends of the legs and their connection with the frame at the spacers changes relative to the vertical, resulting in a spiralling descent of the contact elements as they approach and finally make contact with the fixed electrical conductors on the base panel. By this phenomenon a wiping action of the fingers over the fixed contact occurs thereby insuring a positive electrical contact.

Pressure against any one of the center portions 38 or 38', of the

movable contact elements

30 or 30 is applied through the resilient cover 42 in FIGS. 2 and 5. The resilient cover 42 may be secured adjacent the upper surface of the sheet of gang stamping 32. Thus upon finger pressure against an identifying tab 44 formed on the upper surface of the cover 42 the

center contact

38 or 38 will move vertically and spirally downwardly into wiping electrical contact with the fixed contact element 22 below it.

To assure complete finger pressure and release thereof via the resilient cover 42, the latter may be spaced slightly from the yieldable stamping 32 which by its own resiliency will assume a flat condition, spaced from the fixed contact element below. In such case the resilient cover 42 is mounted on a second framework of spacers 46 which are aligned perfectly above the lower spacer 24. In addition thereto thefingering tab 44 may be provided with a downwardly projecting bead 48 for engaging the center 33 or 38' of the movable contact element 30 or 30' as the case may be.

In either case, upon downward movement of the de' pending bead 48, the radially extending arms or spokes 39, respectively, may flex slightly upon engagement with the fixed contact element or elements 22 therebelow. Full pressure downwardly forces the contact elements 38 or 38' all the way down to the upper surface of the base panel 20 and the spoke-like fingers 39 or the fingers 39 will flex by reason of their extreme ends engaging the fixed contact elements 22 on the base. This is an important feature of the present invention because by this phenomenon a wiping action of the finger tips over the fixed contacts occurs in addition to the previously-described rotary wiping action.

Under extreme variations in temperature, the resilient cover 42 may have a tendency to become too soft or too rigid. For this reason it is sometimes necessary to reinforce the resilient cover 42 with spring means, such as, a gang type stamped panel or so-called stamping 50 of heat treated or tempered spring steel.

This spring steel stamped panel 50 is formed much the same as the tempered beryllium copper sheet 32 for the movable contact elements 30 as previously explained. It may have the same configuration as the sheet 32 in FIG. 4 or may utilize a configuration as shown in my previously mentioned copending application.

As illustrated in FIGS. 2 and 5, the spring steel stamping 50 is supported on the spacers 46. The resilient cover 44 may have depending ribs 52 registerable with the

spacers

44 and 24 for support thereon. It will be noted that each ring-like center of the spring steel stamping 50 is secured to the resilient cover 42 in annular grooves 54 formed in the depending bead 48 axially below each fingering tab 44 on the cover.

PREFERRED EMBODIMENT Referring now to FIGS. 8, 9, and 10, a preferred construction of the multiple switch assembly is shown. This preferred embodiment is similar to that previously described and further includes a plurality of individual push button type keys, modified flexible contacts, return springs and a layer of resilient non-conductive material to minimize contact bounce and to seal the switching zone 26a against contaminates. Consequently, like reference numerals designated by lettered exponents are applied to like parts thereof for the purposes of clarity.

Turning specifically to FIG. 8, the multiple switch assembly, in its preferred embodiment, comprises a nonconductive base panel 20a having a photographically printed circuit etched on its upper surface, to provide a plurality of fixed contact elements 22a thereon. The fixed contact areas are divided by a screen of spacers 24a into separate switch areas or zones 260. Each of the contact elements 22a may have independent electrical connections to one side of an electrical circuit in a manner as previously described in connection with FIGS. 1, 2, 5 and 12.

For convenience, the assembly may be mounted on a backing plate or mounting board 56 with a sheet of insulating material 58 provided to isolate the printed circuit board 200 from the backing plate 56.

The movable contact elements 30a, formed in a gang stamping 320, are mounted above the fixed contacts 22a and spaced slightly therefrom by the spacer elements 24a.'A thin sheet of resilient insulating material such as, for example, neoprene rubber 60, is placed over the movable contact members 300. This layer has a damping effect on the contacts thereby minimizing contact bounce as the circuit is opened and closed. The layer 60 further effectively seals the switching zone 26a and prevents contaminating materials from entering therein. A second framework of spacers 46a placed over the assembly are aligned with the lower spacers 24a to define an opening above the switching area and support the return spring assembly 500. Lastly, the push button assembly or keyboard 62 carrying a plurality of independent keys 64 is mounted above the switching zones. Individual plungers 66 connected at one end to the keys 64 rest on their opposite end on the return springs 50a and are supported for linear movement in a guide plate 68.

The construction of the modified movable contact elements 30a shown in FIG. is similar to that shown in FIG. 6. The movable contact elements 30a are preferably formed in a gang stamping 32 or chemically etched on a sheet of tempered beryllium copper or other material having a high degree of electrical conductivity. In the gang stamping 32 thus formed, a contact element for each switch unit is confined within a frame 34a which registers with the spacers 240 on the base panel 20a for support above the fixed contact elements 22a. Within this frame 34a, one or more legs 36a extend centrally inwardly to the solid center contact portion 38a to support the same in yieldable suspension above the fixed contact element in each switch cavity or area 26a as shown in FIG. 8. The movable contact element 30 is in the form of a solid flat center 38a from which a plurality of fork-like contact fingers 39a extend radially outwardly for yieldable contact with the fixed contact elements 22 on the base panel. The legs 36a afford yieldable suspension to the flat center 380. Four such legs 36a are preferable within each frame 340. Each leg 36a is connected at its base end 40a to one side of the frame 34a adjacent one corner thereof. The legs 36a are separated from the adjacent right angle side of the frame and extend across the square frame 34a to a point just short of the adjacent leg 36a. Each leg terminates in a bend 41a the extreme end 42a of which is integrally connected to the contact center 38a. The extreme end 42a of each leg 36a terminates at approximately l35 angle relative to the corner of the frame 34 where the particular leg 36a is connected to the frame.

When downward pressure is applied against the solid center contact portion 38a, the legs 36a associated therewith are flexed while the contact fingers move spirally downwardly perpendicular to the flat upper surface of the printed circuit, i.e., turning while moving vertically within the switch zone 26a confining the same. In other words, the fingers 390 turn or rotate while moving downwardly within the switch zone 2611. This rotating action is created by reason of the hingelike flexing action of the legs 36a from one plane into another. As the annular flat ring-like member 38a on the inner ends of the legs 36a is depressed, the distance between the ends of the legs and their connection with the frame at the spacers changes relative to the vertical, resulting in a spiralling descent of the contact elements as they approach and finally make contact with the fixed electrical conductors on the base panel. This is an important feature of the present invention because by this phenomenon a wiping action of the fingers over the fixed contact occurs thereby insuring a positive electrical contact.

The return spring 500 for the push button assembly is illustrated in detail in FIG. 9. The return springs are preferably heat treated or tempered spring steel and are formed in much the same manner as the movable contact elements 30 as previously explained. The sheet of springs may be stamped or chemically etched in a manner well-known to those skilled in the art. The individual springs 50a are contained within a frame conforming to the spacers 46a for support thereon as illustrated in FIG. 8. The spring member is formed within each frame 70. At its center an annular disk-shaped member 72 is supported inside a central ring-like member 74 by a plurality of legs 76. Each of the legs are integrally connected at one end to the ring 74, spirally encompassing at least a portion of the disk member 72 and are connected to the disk at their other end approximately l from their connection to the ring 74. Each disk 72, then, is flexibly and yieldably supported within the ring member 74.

The ring member itself is supported within the frame on at least a pair of spiral-like legs 78. The legs are connected at one end 80 to opposite sides of the frame and extend completely around the center ring member 74 where they are connected at their opposite ends 82 to the ring member. The connection of the leg 78 to the ring 74 is preferably at a point on the ring in line with the end 80 of the leg 78.

The spring member 500 may be formed with a slight depression 84 at its center portion 72 within the ring member 74 as illustrated in FIG. 8. This depression is arranged to be in alignment, when assembled, with the center portion 38 of the movable contact assembly 30 so that downward movement is transmitted directly to the center portion thereof. The center ring 74 may be formed in an upward direction with respect to the frame. This additional formation of the spring member provides a means for controlling the pre-travel, preload and over-travel of the push button and switching means. In effect, by varying the spring formation, a touch control for the push buttons can easily be provided.

The operation of the switch is similar to that illustrated in FIG. 2. As the key 64 is depressed, the corresponding downward movement of the plunger 66 and spring member 50a is effected through the opening 86 in the spacer 46a. As the center portion 72 of the spring 58 contacts the resilient member 60, the downward force is transmitted therethrough to the flat ring 38a of the movable switch contacts. The contacts 39a are moved downwardly with rotary wiping action until contact is made with the fixed contact elements 22a and the circuit is completed. As the key is released, the spring will return the plunger and its associated key to its original position as the movable switch contacts are also moved upwardly to their first position, that is, spaced apart from the fixed contacts.

An alternate embodiment of the construction shown in FIG. 8 is illustrated in FIG. ll. In this embodiment the insulating material 60a is provided with expanded portions or air pockets 88 positioned on each of the movable contacts 38a. Downward movement of the plunger transmitted through the air pocket 88 will cause the contacts to move downwardly with the spiral, rotary wiping action as previously described. As the key is released, the contacts will return to their normal open or upward position.

In some applications, this embodiment may be utilized as a direct replacement for the insulating material 60a shown in FIG. 8 to more effectively eliminate contact bounce.

In other applications it may be desirable to eliminate the upper spacers 46a and the return springs 50a of FIG. 8, having the key plunger 66 acting directly on the air pockets 8% to move the contacts downwardly. The elimination of component parts will result in a more compact package together with a corresponding reduction in unit cost.

From the foregoing, it will be appreciated that the multiple switch construction of the present invention provides a simple form of switching means which is inexpensive from the standpoint of manufacture and involves a minimum number of parts by reason of printed type circuitry and mass stamping or etching of switching elements with the least effort in labor assembly. The switching contacts thus formed and constructed result in relatively, flat, plate-like switchbanks, keyboards, and the like, having a wide application in any industry requiring momentary switching functions.

While the preferred embodiments of this invention have been illustrated in detail, it will be apparent to those skilled in the art that many modifications thereof may be made without departing from the concepts disclosed herein. Such modifications are to be considered as included in the following claims, unless these claims by their language expressly state otherwise.

The embodimentsof the invention in which an exclusive property or privilege is claimed are defined as follows.

l. in a multiple switch construction in which stratified laminates superimposed in spaced relation and in close proximity one upon another comprise in combination:

1. an electrically non-conductive base panel having one surface thereof divided into a plurality of switching areas;

2. a fixed electrically conductive switch element fixed upon said surface of said base panel within each of said switching areas thereon;

3. depressible means supported on said base panel in spaced relation to said surface thereof and selectively depressible toward the latter within any one of said switching areas thereon;

4. a flexible electrically conductive switching element having frame-like portions thereof conforming to and supported in spaced relation to said base panel with said depressible means for rotary flexing movement by the latter into electrical contact with the particular fixed electrically conductive switch element within the switching area into which said depressible means is selectively depressed; and

5. a spring laminate of resilient material interposed between said depressible means and said flexible switching element, said spring laminate including a plurality of spring stampings corresponding in number and location to each of said plurality of switching areas providing a positive spring return for each of said depressible means.

2. The multiple switch construction in accordance with that of claim 1, including in combination:

l. spacers mounted on said one surface of said base panel for dividing the same into a plurality of switching areas;

2. non-conductive extensions on said spacers disposed on said frame-like portions of said flexible electrically conductive element;

3. a plurality of integrated frames formed in said spring laminate conforming to said non-conductive extensions of said spacers and secured thereto;

4. a plurality of spider-like legs extending spirally inwardly of each of said frame-like portions and having inwardly bowed ends terminating in a common central ring; and

5. a depending central projection on the underside of said depressible means within each of said switching areas and supported on said common central ring for engaging said flexible element with the fixed electrically conductive element on said base panel upon depression of said depressible means in the respective switching area.

3. A multiple switch construction as claimed in claim 2 and further including a layer of resilient, nonconductive' material interposed between said flexible switching element and said spring laminate, said layer providing a damper for said movable contacts to minimize contact bounce.

4. A multiple switch construction as claimed in claim 3 wherein said depressible means is an array of push buttons supported for linear movement in a guide plate.

5. A multiple switch construction as claimed in claim 1 and further including a layer of resilient, nonconductive material interposed between said flexible switching element and said spring laminate, said layer providing a damper for said movable contacts to minimize contact bounce.

6. A multiple switch construction as claimed in claim 5 wherein said depressible means is an array of push buttons supported fro linear movement in a guide plate.

7. The multiple switch construction in accordance with that of claim 2 wherein said spring laminate further includes a plurality of legs having base ends thereof integrally connected to said common central ring, extending spirally and radially inwardly therefrom and commonly terminating at their opposite ends to form a seat for said depending central projection on said depressible means.

8. In a multiple switch construction having nonconductive spacers defining independent switch areas, the improvement comprising switching elements constructed of a panel divided into a plurality of frame-like portions having integral movable switch elements suspended from said frame-like portions for rotary flexing movement toward a base panel, said integral movable switching elements including:

1. a medial contact means;

2. a plurality of legs having base ends thereof equally spaced about said media] contact means, said legs being integral to said frame-like portions and extending across one side of said frame-like portions and inwardly therefrom into the switching area defined by said spacers; and

3. each of said legs being of a length greater than the shortest distance between its base end and said medial contact element to thereby facilitate flexing of said legs toward said base panel while supporting said medial contact element parallel thereto for substantially linear and rotary movement upon depression thereof in a direction substantially perpendicular to the plane of said panel.

9. In a keyboard assembly for controlling electrical circuits the combination comprising:

1. an electrically non-conductive base panel having a plurality of switch elements fixed therein, said switch elements being divided into a plurality of independent switching zones by a framework of spacers;

2. a panel of flexible switching elements supported in spaced relation to said fixed elements on said spac ers;

3. a resilient insulating layer positioned over said. flexible switching elements, said insulating layer having a plurality of expanded air pockets therein corresponding in number and location to each of I said plurality of switching zones; and

4. a plurality of push buttons supported for linear movement into each of said independent switching zones.

10. in a multiple switch construction in which stratified laminates superimposed in spaced relation and in close proximity one upon another comprise in combination:

4. a flexible electrically conductive switching element supported in spaced relation to said base panel with said depressible means for movement by the latter into electrical contact with the particular fixed electrically conductive switch element within the switching area into which said depressible means is selectively depressed; and

5. a layer of non-conductive resilient material interposed between said depressible means and said flexible switching element, said layer having a plurality of expanded portions therein corresponding in number and location to each of said plurality of switching areas.

11. A keyboard assembly for controlling electrical circuits comprising:

1. an array of pushbuttons;

2. a guide plate supporting said push buttons for linear movement;

3. a layer of resilient material disposed below said push buttons, said layer having a plurality of expanded portions formed therein for each of said push buttons in said array;

4. an electrically non-conductive base panel having a plurality of switch elements fixed thereon;

5. a framework of spacers mounted on said base panel dividing said fixed switch elements into a plurality of individual switching areas;

6. a conductive switching panel supported in spaced relation to said base panel on said spacers and said push buttons, said panel having a plurality of flexible, movable switch elements formed therein, each said switch element movable spirally downwardly by said push buttons against said fixed element within each defined switching area.

12. A keyboard assembly for selectively controlling electrical circuits comprising:

1. an electrically non-conductive base panel;

2. electrically conductive switch elements fixed on the upper surface of said base panel;

3. a framework of spacers mounted on said upper surface of said base panel dividing the same into a plurality of switching areas;

4. flexible, electrically conductive switching elements having frame-like portions thereof conforming to and supported on said spacers in spaced relation to said base;

5. a sheet of resilient, non-conductive material supported on said switching elements;

6. a second framework of spacers aligned with said first-mentioned spacers on said sheet of resilient material;

7. a spring laminate of resilient material having frame-like portions conforming to and supported on said second framework of spacers; and

8. an array of pushbuttons supported for linear movement within a guide plate, said pushbuttons corresponding in location and number to each of said plurality of switching areas, said push-buttons being depressible within any one of said switch areas to move said flexible switch element into contact with said fixed switch element to thereby selectively close an electrical circuit.

13. The keyboard assembly as claimed in claim 12 wherein said electrically conductive switching elements comprise;

l. a medial contact means;

2. a plurality of legs having base ends thereof equally spaced about said medial contact means, said legs being integral to said frame-like portions and extending across one side of said frame-like portions and inwardly therefrom into the switching area defined by said spacers; and

3. each of said legs being of a length greater than the shortest distance between its base end and said me dial contact element to thereby facilitate flexing of said legs toward said base panel while supporting said medial contact element parallel thereto for substantial linear and rotary movement upon depression thereof in a direction substantially perpendicular to the plane of said panel.

114. The keyboard assembly as claimed in claim 12 wherein said spring laminate comprises:

1. a plurality of integrated frames formed in said spring laminate conforming to said non-conductive extensions of said spacers and secured thereto;

2. a plurality of spider-like legs extending spirally inwardly of each of said frame-like portions and having inwardly bowed ends terminating in a common central ring.

15. In a multiple switch construction having movable LII switching elements formed in a panel divided into a plurality of framelike portions, said elements suspended in said frame for rotary and flexing movement toward a fixed contact, said elements within each frame comprising:

a central movable switching element having a plurality of radially extending contact fingers thereon; a plurality of equally spaced flexible legs extending outwardly from said switching elements, said legs turning at an acute angle at a distance away from said element and extending along the sides of said frame through at least the greatest part of the length of said side to an adjacent side for integral connection therewith, said legs forming a hingelike connection between said frame and said element whereby the distance between the ends of said legs and their connection with said frame changes relative to the vertical as said element is depressed resulting in a spiralling rotating descent of said elements and said contact fingers toward said fixed contacts for rotary wiping contact therewith.

16. The multiple switch construction of claim 15 in which said contact fingers extend radially inwardly from said central element.

17. The multiple switch construction of claim 15 in which said contact fingers extend radially outwardly from said central element.

18. The multiple switch construction of claim 17 in which the outermost ends of said radially outwardly extending contact fingers are bifurcated.

Claims

1. In a multiple switch construction in which stratified laminates superimposed in spaced relation and in close proximity one upon another comprise in combination: 1. an electrically non-conductive base panel having one surface thereof divided into a plurality of switching areas; 2. a fixed electrically conductive switch element fixed upon said surface of said base panel within each of said switching areas thereon; 3. depressible means supported on said base panel in spaced relation to said surface thereof and selectively depressible toward the latter within any one of said switching areas thereon; 4. a flexible electrically conductive switching element having frame-like portions thereof conforming to and supported in spaced relation to said base panel with said depressible means for rotary flexing movement by the latter into electrical contact with the particular fixed electrically conductive switch element within the switching area into which said depressible means is selectively depressed; and 5. a spring laminate of resilient material interposed between said depressible means and said flexible switching element, said spring laminate including a plurality of spring stampings corresponding in number and location to each of said plurality of switching areas providing a positive spring return for each of said depressible means.

2. a guide plate supporting said push buttons for linear movement;

2. a panel of flexible switching elements supported in spaced relation to said fixed elements on said spacers;

3. each of said legs being of a length greater than the shortest distance between its base end and said medial contact element to thereby facilitate flexing of said legs toward said base panel while supporting said medial contact element parallel thereto for substantial linear and rotary movement upon depression thereof in a direction substantially perpendicular to the plane of said panel.

3. a resilient insulating layer positioned over said flexible switching elements, said insulating layer having a plurality of expanded air pockets therein corresponding in number and location to each of said plurality of switching zones; and

3. A multiple switch construction as claimed in claim 2 and further including a layer of resilient, non-conductive material interposed between said flexible switching element and said spring laminate, said layer providing a damper for said movable contacts to minimize contact bounce.

4. A multiple switch construction as claimed in claim 5 wherein said depressible means is an array of push buttons supported fro linear movement in a guide plate.

5. A multiple switch construction as claimed in claim 1 and further including a layer of resilient, non-conductive material interposed between said flexible switching element and said spring laminate, said layer providing a damper for said movable contacts to minimize contact bounce.

8. In a multiple switch construction having non-conductive spacers defining independent switch areas, the improvement comprising switching elements constructed of a panel divided into a plurality of frame-like portions having integral movable switch elements suspended from said frame-like portions for rotary flexing movement toward a base panel, said integral movable switching elements including:

11. A keyboard assembly for controlling electrical circuits comprising:

14. The keyboard assembly as claimed in clAim 12 wherein said spring laminate comprises:

15. In a multiple switch construction having movable switching elements formed in a panel divided into a plurality of framelike portions, said elements suspended in said frame for rotary and flexing movement toward a fixed contact, said elements within each frame comprising: a central movable switching element having a plurality of radially extending contact fingers thereon; a plurality of equally spaced flexible legs extending outwardly from said switching elements, said legs turning at an acute angle at a distance away from said element and extending along the sides of said frame through at least the greatest part of the length of said side to an adjacent side for integral connection therewith, said legs forming a hinge-like connection between said frame and said element whereby the distance between the ends of said legs and their connection with said frame changes relative to the vertical as said element is depressed resulting in a spiralling rotating descent of said elements and said contact fingers toward said fixed contacts for rotary wiping contact therewith.