US3665126A

US3665126A - Elongated switch bar apparatus

Info

Publication number: US3665126A
Application number: US60199A
Authority: US
Inventors: William D Gabor
Original assignee: Sanders Associates Inc
Current assignee: Lockheed Corp
Priority date: 1966-10-10
Filing date: 1970-07-01
Publication date: 1972-05-23
Anticipated expiration: 1989-05-23
Also published as: FR95927E; IT799480A; US3588875A

Abstract

A keyboard encoder comprises a set of keys. Each key is in juxtaposition with one or more field-responsive elements associated with that key, the outputs of the field-responsive elements being conveyed to output terminals of the encoder. Actuation of a key alters the field to which the elements associated therewith respond. The number of elements associated with each key and the connections of these elements to the output terminals correspond to the output code for the character represented by the key. Consequently, the responses of the fieldresponsive elements to actuation of a key provide a directly encoded representation of the corresponding character at the output terminals. Also disclosed is an elongated switch bar in which contact is readily made even though the switch bar is depressed at either of the two ends thereof.

Description

' United States Patent Gabor [15] 3,665,126 [4 1 May 23, 1972 [54] ELONGATED SWITCH BAR APPARATUS [60] Division of Ser. No. 598,558, Oct. 10, 1966, Pat. No. 3,588,875, which is a continuation of Ser. No. 496,031, Oct. 14, 1965, abandoned.

52 vs. C] ..200 5 E, 74/483, 200/18,

340/365 51 rm. Cl. ..H0lh 9/26 [58] Field of Search ..200 5 E, 18; 340 173; 74/483 [56] References Cited UNITED STATES PATENTS 2,932,816 4/1960 Stiefel et a] ..200/5 E Primary E.xaminer-Gerald Goldberg Attorney-Louis Etlinger ABSTRACT A keyboard encoder comprises a set of keys. Each key is in juxtaposition with one or more field-responsive elements associated with that key, the outputs of the field-responsive elements being conveyed to output terminals of the encoder. Actuation of a keyalters the field to which the elements associated therewith respond. The number of elements associated with each key and the connections of these elements to the output terminals correspond to the output code for the character represented by the key. Consequently, the responses of the field-responsive elements to actuation of a key provide a directly encoded representation of the corresponding character at the output terminals. Also disclosed is an elongated switch bar in which contact is readily made even though the switch bar is depressed at either of the two ends thereof.

7 Claims, 6 Drawing Figures Patented May 23, 1972 4 Sheets-Sheet l FIG.|

INVENTOR. WILLIAM D. GABOR KMQ W ATTORNEY Patented May 23, 1972 4 Sheets-Sheet If,

I INVENTOR.

WILLIAM D. GABOR @MR #JM ATTORNEY Patented May 23, 1972 3,665,126

4 Sheets-s 4 92 so 2 a) v //////7// 1 9 & FIG.6 VENT I WILL! 0G R BY RMRW TORNEY ELONGATED SWITCH BAR APPARATUS This application is a division of my co-pending application Ser. No. 598,558, filed Oct. 10, 1966 for Character Encoder, now U.S. Pat. No. No. 3,588,875, issued June 28, 1971, which in turn is a continuation-in-part of another application Ser. 496,031, filed Oct. 14, 1965 for Keyboard Encoder, now abandoned. BACKGROUND OF INVENTION This invention claim to a compact keyboard encoder having no moving parts except for the keys themselves. Actuation of a key changes an electrical characteristic of one or more sensors according to the coded representation of a character associated with the key. Converters in the encoder transform these changes in the characteristic to digital signals identifying the character.

A digital encoder of the type having a keyboard input provides the link between a human operator and automatic data processing equipment. The keyboard appears similar to a typewriter keyboard and for each keyboard character selected by the operator, the encoder produces a series of electrical signals corresponding to the digits in a coded representation of the character. In an illustrative application, the operator uses the keyboard to type computer instructions and input data. The encoder converts the selected characters to their corresponding digital signals, which are then recorded on a magnetic tape or on a series of punched cards.

Many prior keyboard encoders employ keyboards having mechanical linkages similar to those in conventional office typewriters or teletype machines. High operating noise and relatively frequent maintenance, due to wear and maladjustment, restrict the performance of such mechanical encoders.

Electrical switches having moving contacts are also used in prior keyboard encoders. However, dirt on the contacts and contact oxidation and wear cause mechanical switches to have varying non-zero resistances between engaged contacts. As a result, encoders employing moving contacts have limited reliabilityand their performance often deteriorates with age as well as with use.

A further disadvantage of prior keyboard encoders is their relatively large size and high cost.

BRIEF SUMMARY OF INVENTION terized by relatively low cost;

Another object of the invention is to provide an encoder of the above type characterized by the absence of mechanical linkages and moving electrical contacts.

A further object of the invention is to provide an encoder of the above type characterized by high reliability. A more specific object of the invention is to provide a keyboard encoder whose output signals are relatively free from errors and which is capable of prolonged use with minimal maintenance.

A still further object of the invention is to provide a keyboard encoder characterized by simplicity of design and low-cost fabrication.

Briefly, switching apparatus embodying the invention includes a panel having opposed inner and outer surfaces. An elongated switchbar having first and second ends longitudinally spaced apart and opposed top and bottom surfaces is disposed in an aperture through the panel and depressable from the outer surface of the panel. The switch bar also has an electrical element mounted adjacent its bottom surface thereof for movement with the switch as it is depressed. A first pair of first and second sensing elements and a second pair of third and fourth sensing elements are disposed inwardly from the bottom surface of the switchbar. Each sensing element in the first pair are closer to a first end of the switchbar than are the sensing elements in the second pair. Each of the sensing 7 elements is electrically coupled with the electrical elements on the bottom surface of the switchbar and has a variable electrical characteristic selected from the two characteristics impedence and attenuation. The first and third sensing elements are connected together so as to combine their electrical characteristics and the second and fourth elements are connected together so as to combine their electrical characteristics. The sensing elements and the electrical elements are so arranged that the combined characteristics of the first and third element change by substantially the same relative amount as the combined characteristics of the second and fourth sensing elements when the switchbar is depressed to change the position of the electrical elements relative to any one of the first pair of elements the second pair of elements and both pair of elements. By positioning one pair of the sensing elements beneath one end of the elongated switchbar and the other pair of elements beneath the other end thereof, and interconnecting the elements of the two pairs in the manner aforesaid, the change in impedance or attenuation characteristic, as the case may be, is substantially the same when the bar is pushed down at only one end as when it is pushed down so as to be parallel to the plane in which the sensing elements are disposed.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

BRIEF DESCRIPTION OF THE DRAWING In the accompanying drawings like reference characters denote like components, and:

FIG. 1 is a pictorial representation, partly broken away, of an electronic display unit incorporating a keyboard encoder embodying the invention;

FIG. 2 is a schematic representation of a keyboard encoder embodying the invention and employing variable capacitors to sense actuation of the various keyboard buttons;

FIG. 3 is an exploded view of the keyboard of FIG. 1;

FIG. 4 is a fragmentary side elevation view, partly in section, of the keyboard of FIGS. 1 and 3; and

FIGS. 5 and 6 show different constructions for a space button for a keyboard embodying the invention.

DESCRIPTION OF PREFERRED EMBODIMENT For a detailed description of the elongated switchbar apparatus embodying the present invention, reference is made to the aforementioned U.S. Pat. No. 3,588,875, which patent is incorporated herein by reference. In particular, the elongated switchbar apparatus embodying the invention is shown in FIGS. 1 through 6 and described in detail beginning at column 3 line 61 through column 6, line 2 and beginning at column 10, line 69 through column 12, line 32.

I claim 1. Switching apparatus comprising in combination A. a panel having opposed inner and outer surfaces,

B. an elongated switch bar 1 having first and second ends longitudinally spaced apart, and opposed top and bottom surfaces,

2. disposed in an aperture through said panel and depressible from the outer surface of said panel,

3. having an electrical element mounted adjacent said bottom surface thereof for movement therewith,

C. means forming a first pair of first and second sensing elements and a second pair of third and fourth sensing elements,

1. said sensing elements being disposed inwardly from said bottom surface of said switch bar,

2. each sensing element in said first pair thereof being closer to said first end of said switch bar than each sensing element in said second pair thereof,

3. each sensing element being electrically coupled with said electrical element and having a variable electrical characteristic selected from the two characteristics impedance and attenuation, the value of said characteristic being determined by the position of said electrical element relative to the sensing element,

4. said first and third sensing elements being connected together so as to combine their said electrical characteristics, and said second and fourth sensing elements being connected together so as to combine their said electrical characteristics, and 5. said sensing elements and said electrical element being so arranged that the combined characteristics of said first and third sensing elements change by substantially the same relative amount as the combined characteristics of said second and fourth sensing elements when said switch bar is depressed to change the position of said electrical element relative to any one of said first pair of sensing elements, said second pair of sensing elements, and both pairs of sensing elements. 2. Apparatus as defined in claim 1 in which said sensing elements are disposed substantially co-planar with each other and uniformly spaced from said panel.

3. Apparatus as defined in claim 1 in which A. each sensing element comprises an electrical conductor,

and

B. the conductors in each pair thereof are disposed side by side with each other in the direction transverse to the longitudinal direction of said switch bar and transverse to the direction in which said button means is depressible.

4. Apparatus as defined in claim 1 in which A. each sensing element comprises an electrical conductor,

B. the conductors in each pair thereof are disposed side by side with each other in the direction in which said switch bar is elongated, and

C. said first and second conductors are successively ordered from said first end of said switch bar the same as the successive order of said third and fourth conductors from said second end of said switch bar.

5. In an electronic keyboard encoder, the combination of A. a panel having opposed inner and outer surfaces,

B. an insulating board disposed inwardly from the said panel,

C. an elongated spacebar 1. having first and second ends spaced apart along the direction in which said spacebar is elongated,

2. having a flat elongated bottom surface,

3. carrying a coupling element forming an electrically conductive surface proximate to and substantially parallel to said bottom surface,

4. disposed in an aperture through said panel and depressible to move said coupling element toward said insulating board,

D. a first pair of first and second capacitor plates and a second pair of third and fourth capacitor plates,

1. said plates being on said insulating board and aligned opposite said coupling element,

2. said first pair of plates being closer to said first end of said spacebar than said second pair of plates,

E. means connecting said first and third plates together,

F. means connecting said second and fourth plates together,

G. said plates being so spacially arranged that the sum of the spacings between said coupling element and each of said first and third plates changes by substantially the same relative amount as does the sum of the spacings between said coupling element and each of said second and fourth plates when said spacebar is depressed to change the spacings between said coupling element and each pair of plates by the same amount as well as and by different amounts. 6. Electrical switching apparatus comprising in combination A. a support,

ing on it which also acts on said coupling means, (2) said first and third sensing elements bemg connected together so as to combine their associated transfer functions and said second and fourth sensing elements being connected together so as to combine their associated transfer functions,

(3) the position of said coupling means relative to said pairs of sensing elements being different in said different depressed positions, and

(4) said sensing elements and said coupling means being so disposed that the combined transfer functions associated with said first and third sensing elements change movement substantially the same relative amount as the combined transfer functions associated with said second and fourth sensing elements when said switch bar is moved to any one of its depressed positions.

7. Electrical switching apparatus comprising A. a support, B. a switch bar elongated between first and second ends,

1. said switch bar having opposed inner and outer surfaces, and being mounted for movement along a first direction parallel to the spacing between said inner and outer surfaces from a normal position to an actuated position,

C. first and second plunger elements spaced apart along said bar, each plunger element 1. being movable along said first direction, and

2. being moved in said first direction by said button upon movement of the nearer end of said button toward said depressed position,

D. means forming first and second electrical sensors 1. each sensor being associated with one of said plunger elements, 2) each sensor comprising a sensing element and an electrical element carried on said associated element, (3) each sensing element a being relatively fixedly mounted with said support and disposed adjacent said associatedplunger element so that movement of the plunger element in said first direction moves the electrical element thereon relative to the sensing element and changes a field acting on the sensing element, and

(b) having an electrical transfer function the value of which is determined by said field acting on it,

4 said first and second sensing elements being connected together so as to combine their said transfer functions.

Claims

1. Switching apparatus comprising in combination A. a panel having opposed inner and outer surfaces, B. an elongated switch bar 1 having first and second ends longitudinally spaced apart, and opposed top and bottom surfaces, 2. disposed in an aperture through said panel and depressible from the outer surface of said panel, 3. having an electrical element mounted adjacent said bottom surface thereof for movement therewith, C. means forming a first pair of first and second sensing elements and a second pair of third and fourth sensing elements, 1. said sensing elements being disposed inwardly from said bottom surface of said switch bar, 2. each sensing element in said first pair thereof being closer to said first end of said switch bar than each sensing element in said second pair thereof, 3. each sensing element being electrically coupled with said electrical element and having a variable electrical characteristic selected from the two characteristics impedance and attenuation, the value of said characteristic being determined by the position of said electrical element relative to the sensing element, 4. said first and third sensing elements being connected together so as to combine their said electrical characteristics, and said second and fourth sensing elements being connected together so as to combine their said electrical characteristics, and 5. said sensing elements and said electrical element being so arranged that the combined characteristics of said first and third sensing elements change by substantially the same relative amount as the combined characteristics of said second and fourth sensing elements when said switch bar is depressed to change the position of said electrical element relative to any one of said first pair of sensing elements, said second pair of sensing elements, and both pairs of sensing elements.

2. having a flat elongated bottom surface,

2. said first pair of plates being closer to said first end of said spacebar than said second pair of plates, E. means connecting said first and third plates together, F. means connecting said second and fourth plates together, G. said plates being so spacially arranged that the sum of the spacings between said coupling element and each of said first and third plates changes by substantially the same relative amount as does the sum of the spacings between said coupling element and each of said second and fourth plates when said spacebar is depressed to change the spacings between said coupling element and each pair of plates by the same amount as well as and by different amounts.

2. being moved in said first direction by said button upon movement of the nearer end of said button toward said depressed position, D. means forming first and second electrical sensors

2. Apparatus as defined in claim 1 in which said sensing elements are disposed substantially co-planar with each other and uniformly spaced from said panel.

3. Apparatus as defined in claim 1 in which A. each sensing element comprises an electrical conductor, and B. the conductors in each pair thereof are disposed side by side with each other in the direction transverse to the longitudinal direction of said switch bar and transverse to the direction in which said button means is depressible.

3. having an electrical element mounted adjacent said bottom surface thereof for movement therewith, C. means forming a first pair of first and second sensing elements and a second pair of third and fourth sensing elements,

4. disposed in an aperture through said panel and depressible to move said coupling element toward said insulating board, D. a first pair of first and second capacitor plates and a second pair of third and fourth capacitor plates,

4. said first and third sensing elements being connected together so as to combine their said electrical characteristics, and said second and fourth sensing elements being connected together so as to combine their said electrical characteristics, and

4. Apparatus as defined in claim 1 in which A. each sensing element comprises an electrical conductor, B. the conductors in each pair thereof are disposed side by side with each other in the direction in which said switch bar is elongated, and C. said first and second conductors are successively ordered from said first end of said switch bar the same as the successive order of said third and fourth conductors from said second end of said switch bar.

5. In an electronic keyboard encoder, the combination of A. a panel having opposed inner and outer surfaces, B. an insulating board disposed inwardly from the said panel, C. an elongated spacebar

5. said sensing elements and said electrical element being so arranged that the combined characteristics of said first and third sensing elements change by substantially the same relative amount as the combined characteristics of said second and fourth sensing elements when said switch bar is depressed to change the position of said electrical element relative to any one of said first pair of sensing elements, said second pair of sensing elements, and both pairs of sensing elements.

6. Electrical switching apparatus comprising in combination A. a support, B. an elongated switch bar mounted with said support for movement to different depressed positions, C. electrical coupling means mounted for movement with said switch bar, D. means forming a first pair of first and second electrical sensing elements and a second pair of third and fourth electrical sensing elements,