US3641567A

US3641567A - Noncontacting keyboard and interlockng system

Info

Publication number: US3641567A
Application number: US17771A
Authority: US
Inventors: Ivan O Fieldgate
Original assignee: Potter Instrument Co Inc
Current assignee: Potter Instrument Co Inc
Priority date: 1970-03-09
Filing date: 1970-03-09
Publication date: 1972-02-08
Anticipated expiration: 1989-02-08

Abstract

A noncontacting keyboard encoder having an interlocking system for preventing erroneous readouts in response to a concomitant actuation of a plurality of keys in which there is provided for each character to be encoded a key-operated floating plate which is eccentrically biased to a position at which respective saturating magnets carried thereby are positioned adjacent a column of locations at which saturable cores are selectively arranged in a coded pattern and adjacent a saturable gate core spaced from the column normally to inhibit generation of signals on respective output lines each of which is common to corresponding positions of all columns and on a readout gating line common to all gate cores in response to an interrogating signal on an interrogating line threading all cores. Actuation of a key first enables the associated gate core and then the associated column cores and release of the key first disables the column cores and then the gate core to prevent readout until one key is fully actuated and when two keys are concomitantly actuated.

Description

nite States Patent .Fieldgate Feb. 8, 1972 [54] NONCONTACTING KEYBOARD AND Primary Examiner-John W. Caldwell INTERLOCKNG SYSTEM Assistant Examiner-Marshall M. Curtis Attome Shenier and OConnor [72] inventor: lvan O. Fieldgate, Halesite, N.Y. y Y [73] Assignee: Potter Instrument Company, Inc., Plain- [57] ABSTRACT A noncontacting keyboard encoder having an interlocking [22] Filed: Mar. 9, 1970 system for preventing erroneouareadouts in response to a concorrutant actuation of a plurality of keys in which there is PP 17,771 provided for each character to be encoded a key-operated floating plate which is eccentrically biased to a position at 52] us. c1. ..340/365, 178/17 c, 340/174 PM which 'P sau'afing 'l hereby tioned ad acent a column of locations at which saturable cores [S1] Int.Cl G08c1/00 l l M d d [58] Field ofSearch ..340/365, 174 PM; 178/79, 17, arrange a c e a saturable gate core spaced from the column normally to ml78/l7 A, 17 D,101,l02, 105-110 h1b1t generation of signals on respective output lines each of [56] References Cited 7 which is common to corresponding positions of all columns and on a readout gating line common to all gate cores in UNITED STATES T response to an interrogating signal on an interrogating line a threading all cores. Actuation of a key first enables the as- 2,64l,753 6/1953 Ohwa. ..340/365 sociated gate col-e and than the associated column cores d 3,407,396 10/1968 Luklanov-m 340/ 174 release of the key first disables the column cores and then the 3,495,236 2/1970 M al "340/365 gate core to prevent readout until one key is fully actuated and i x z i l when two keys are concomitantly actuated. e e

1 Claims, 6 Drawing Figures PAIENEnrm 81972 SHEET 1 BF 2 INVENTOR Iva/7 F/e/dj a To? QTTORNEYS PAIENIEBFEB 8 Ian SHEET 2 OF 2 QB wmwmSau INVENTOR MZM HTToRNE Y5 NONCONTACTING KEYBOARD AND INTERLOCKNG SYSTEM BACKGROUND OF THE INVENTION It has been suggested in the prior art that a noncontacting keyboard be provided in which a coded group of output bits representing a character are produced in response to actuation of a key to which the character corresponds. The copending application of Charles B. Pear, .Ir. Ser. No. 715,857, filed Mar. 25, 1968, now US. Pat. No. 3,573,808 discloses A Keyboard or Other Similar Apparatus for Converting Mechanical Movement to a Binary Electrical Signal" in which saturable cores are selectively located at the intersections of a plurality of rows and columns to represent respective characters. A respective readout line is common to cores of each row and an interrogating signal line is common to all cores. A respective key-actuated saturating magnet associated with each column normally is so positioned that the cores of the column are saturated and no outputs are generated in response to the interrogating signal. When a particular key is operated the associated cores are enabled so that the interrogating signal produces output signals on those output lines with which cores in that column are associated.

In an arrangement of the type described in the copending application referred to hereinabove, the danger exists that an erroneous readout will be provided if more than a single key is operated at one time. In an effort to solve this problem, the copending application suggests that an auxiliary row of cores be provided with one core in each column and with the outputs of this row additive with the result that if more than one key at a time is pressed an inordinately large output signal appears on the extra row output line, which signal is used to inhibit readout. This arrangement is not as certain as is desirable in preventing erroneous readouts. That is, in the proposed arrangement, if two keys are simultaneously only partially depressed the extra row output signal may not be large enough to inhibit readout and yet both coded outputs are generated and they may be sufficiently great to provide a readout. Stated otherwise, if the extra row signal amplitude detector of that system is, for example, set to inhibit, upon the occurrence of an extra row signal in excess of 15 percent of the extra row output when one key is depressed, partial actuation of two keys may cause each to provide anextra row output which is less than 75 percent of its normal output, or an aggregate extra row output of less than 150 percent of normal, and readout is not inhibited. Under these conditions, erroneous coded indications will be translated to the output register which may respond to coded signal inputs of only from about 25 percent to 50 percent of normal. v

I have inventeda noncontacting keyboard and interlocking system' which overcomes the defect of the system described hereinabove. My keyboard ensures against erroneous readouts when more than a single key is actuated at one time. It is certain in its operation. It retains all of the advantages of noncontacting keyboards of the prior art.

SUMMARY OF THE INVENTION One object of my invention is to provide a noncontacting keyboard and interlocking system which overcomes the defects of noncontacting keyboards of the prior art.

Another object of my invention is to provide a noncontacting keyboard and interlocking system which is more certain in operation than are noncontacting keyboards of the prior art.

A further object of my invention is to provide a noncontacting keyboard and interlocking system which ensures against erroneous readouts.

Still another object of my invention is to provide a noncontacting keyboard and interlocking system which cannot produce a readout unless a key is fully depressed.

Other and further objects of my invention will appear from the following description.

In general my invention contemplates the provision of a noncontacting keyboard and interlocking system in which for each of the characters I provide a module including a floating plate which is eccentrically biased to a position at which respective saturating magnets are adjacent to a column of positions in which saturable cores are disposed in a coded arrangement corresponding to a character and adjacent to a saturable gate core normally to prevent generation output signals on respective readout lines each of which is associated with corresponding locations of all columns and to prevent an output on a gate core line common to all gate cores in response to an interrogating signal on a line common to all cores. A key attached to the plate is adapted to be actuated first to enable the gating core and then to enable the column cores and is adapted to be released first to disable the column cores and then the gating core. An amplitude sensitive device responsive to the signal on the gate core lines disables the readout when the signal exceeds a certain level.

I BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings which form part of the instant specification and which are to be read in conjunction therewith and in which like reference numerals are used to indicate like parts in the various views:

FIG. 1 is a perspective view with parts broken away and with other parts in section of one module of my noncontacting keyboard and interlocking system.

FIG. 2 is an end elevation of the module shown in FIG. I before the key is pressed.

FIG. 3 is an end elevation of the key shown in FIG. 2 during the initial part of the actuating movement of the key.

FIG. 4 is an end elevation of the key shown in FIG. 3 when the key is fully actuated.

FIG. 5 is an end elevation of the module shown in FIG. 2 illustrating the initial portion of the return movement of the key to its normal position.

FIG. 6 is a schematic view of my noncontacting keyboard and interlocking system.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1 for each character which is to be encoded by use of my keyboard I provide a module indicated generally by the reference character 10 associated with a column indicated generally by the reference character 12 of locations determined by the points of intersection of a plurality of character readout lines 14 with an interrogating line 16. While in FIG. 1 I have illustrated only five such locations, it will be appreciated that I provide as many locations as are required by the code in order to represent the number of characters to be encoded. In one system in general use in the prior art eight such locations per column are provided.

I so position saturable cores l8 atthe various locations of the column 12 as to generate a coded group of output signals representing the particular character to be encoded by the module. This output group may be in the form of binary bits in the natural or any other binary code. The arrangement is such that the code output lines 14 intersect the interrogating line 16 generally at right angles and that both the coded output lines and the interrogating lines thread the cores 18 with the cores being disposed at an angle of about 45 both to the output line 14 and to the interrogating line 16. I may make the cores from any suitable ferromagnetic material having a square hysteresis loop. The cores are supported in position in the column by any suitable means known to the art.

In the particular embodiment which I have illustrated, I have shown cores 18 in four of the five coded positions. Each of the modules 10 further includes a gate core 20 similar to cores 18. Core 20 is threaded by the interrogating line 16 and by a gate signal output line 22. The orientation of the core 20 with reference to the

lines

16 and 22 is similar to that described hereinabove in connection with cores 18.

Each module 10 has a support plate 24 carrying a thin elongated permanent magnet 26 and a small magnet 28 respectively associated with the cores 18 of column 12 and with the gating core 20.

Magnets

26 and 28 may be formed from any suitable material known to the art. One material which is suitable for my use is a magnetic rubber in the form ofa strip having a width of about l/l6th of an inch and a thickness of 141th of an inch which will satisfactorily saturate the

cores

18 and 20 when the magnets are within a distance of about 20 mils from the cores. A material of this type is available from B. F. Goodrich Corporation and from Leyman Corporation of Cincinatti, Ohio. It is a rubberlike material heavily impregnated with barium or strontium ferrite powder so oriented that it is best magnetized along its thinnest dimension.

A spring 30 connected between an off centerline point on plate 24 and the frame 32 of the keyboard normally biases plate 24 to a position at which

magnets

26 and 28 respectively are sufficiently close to the cores l8 and to the core 20 to saturate all cores. I pivotally connect the shaft 34 of a key 36 to the plate 24 at the centerline thereof by means ofa pin 38 supported in a bracket 40 on the plate. I locate the pivotal connection between shaft 34 and plate 24 so as to be generally in the center of the plate.

Stops

42 and 44 carried by the frame at a location below the

cores

18 and 20 limit the movement downward of plate 24 in a manner to be described.

Referring now to FIGS. 2 to 5, from the structure thus far described it will be apparent that spring 30 normally biases plate 24 to a position at which all cores are saturated. This position ofthe parts is illustrated in FIG. 2. When the key 36 is pressed, owing to the biasing action of the spring 30 the plate first rocks in a counterclockwise direction as viewed in FIG. 3 until the left edge engages stop 42. In this position of the parts, magnet 28 is moved away from the gating core while the magnet 26 remains in position adjacent the code cores 18 so that the former is unsaturated and the latter remain saturated. Further pressure on the key causes plate 24 to rock around its left edge until the plate engages both stops 42 and 44 as shown in FIG. 4 in which position both magnets are remote from the cores with which they are associated and all cores are unsaturated. When the key 36 is released, biasing spring 30 causes the plate first to rock about its left edge until magnet 26 is restored to its position adjacent cores 18 to saturate these cores. After that occurs the left edge of the plate moves upwardly until magnet 28 is again adjacent core 20.

Referring now to FIG. 6, I have a schematic view ofa noncontacting keyboard wherein there are provided a multiplicity of the modules indicated generally by the

reference characters

10, 46, 48, 50 and 52. Since all of the modules are of the same construction those other than module will not be described in detail. An interrogating pulse generator 54 of any suitable type known to the art supplies interrogating pulses to the line 16 which threads all of the cores. I couple the readout lines 14 and the gate readout line 22 to respective output amplifiers 56 each of which supplies one input of a two-input AND-circuit 58.

Preferably the cores of a row threaded by a line 14 are so oriented that outputs of adjacent cores are subtractive to minimize noise in the output. The cores threaded by the gating signal output line however are arranged to add.

I also apply the output from the gate cores carried by line 22 to one input terminal 60 of a comparator 62 the other input terminal 64 of which carries a suitable potential such for example as a potential of a magnitude which is greater than that which would normally be provided if a single core 20 were enabled but less than that which would be produced if more than one gating core 20 is enabled. By way of example I may set the reference potential at terminal 64 to be about one and a half times the input which would be provided if only a single core were enabled.

I so arrange the comparator 62 as to provide an output signal in response to an input signal so long as the input signal at terminal 60 does not exceed one and a half times the normal input. Under these conditions signals appearing on lines 14 will be passed by the AND-circuit 58 to respective pulse lengthening circuits 66 which may for example be one-shot multivibrutors. Respective driver amplifiers 68 apply the multivibrator outputs to the input terminals of a suitable register 70 of any suitable type known to the art.

In order to reset register 70 when a key is released I couple the output of the lowermost line of register 70 together with the signal on line 22 to a two-input AND-circuit 72 which provides the reset signal for the register.

In operation of my keyboard and interlocking system the keys 36 corresponding to the desired characters normally are pressed in sequence. When a key is operated plate 24 first pivots around its right-hand edge as viewed in FIGS. 2 and 3 from the position shown in FIG. 2 to the position shown in FIG. 3 to move magnet 28 away from core 20 to enable that core. When enabled, the core. in response to an interrogating signal, provides its full normal output on line 22. Continued pressure on the key 36 moves plate 24 from the position shown in FIG. 3 to the position shown in FIG. 4. In this last position, the gating core 20 is fully enabled and all of the cores 18 of that module likewise are enabled. Under these conditions in response to an interrogating pulse a coded group of outputs corresponding to the character appear on lines 14. At the same time a gating pulse of normal magnitude appears on line 22 so that AND-circuits 58 pass the coded outputs to the register 70. 7

From the foregoing, it will be seen that a full magnitude gating pulse for any character is produced before any coded outputs are available on line 14. Thus, if two keys are even partially pressed together I ensure that the magnitude of the signal on line 22 is sufficiently great to inhibit readout before anything is available to be read out.

Upon release of the key 36 it first moves from the position shown in FIG. 4 to the position shown in FIG. 5 under the action of spring 30 to disable the coded cores 18 before the gating core is disabled. Thus, ifa second key is pressed before the first key has completely reset then the output at line 22 is great enough to inhibit readout before the second coded output is available.

It will be seen that I have accomplished the objectsof my invention. I have provided a noncontacting keyboard and interlocking system which overcomes the defects of noncontacting keyboards of the prior art. My keyboard ensures against erroneous readouts when more than one key at a time is actuated. It prevents generation of a coded output corresponding to operation of a key until a full magnitude gating pulse is available.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of my claims. It is further obvious that various changes may be made in details within the scope of my claims without departing from the spirit of my invention. It is, therefore. to be understood that my invention is not to be limited to the specific details shown and described.

Having thus described my invention, what I claim is:

1. An interlock system for keyboard which employs a plurality of groups of magnetic cores arranged in code patterns comprising in combination:

code signal output means threading the cores of said plurality of groups and coupling them to an output register;

an interlock core disposed adjacent to each of said plurality groups of cores;

a plate;

means mounting said plate for movement respectively between a position adjacent each of said plurality of cores and a position remote from said cores;

a pair of magnets carried by each said plate one of said magnets saturating said group of cores and one saturating said interlock core when said plate is in said adjacent position;

means for moving said plate from said first position to said second position including;

means constraining one side of said plate causing said plate to move through an intermediate position at which said interlock core-saturating magnet is remote from said interlock core while said group of cores saturating magnet first position; and

is adjacent said group of cores as said plate moves from means responsive to two or more of said interlock cores in said first position to said second position and for conan unsaturated State to decouph? Said P' of groups straining said plate to move through said intermediate ofcores from Said regimen position as said support moves from said second to said 5

Claims

1. An interlock system for keyboard which employs a plurality of groups of magnetic cores arranged in code patterns comprising in combination: code signal output means threading the cores of said plurality of groups and coupling them to an output register; an interlock core disposed adjacent to each of said plurality groups of cores; a plate; means mounting said plate for movement respectively between a position adjacent each of said plurality of cores and a position remote from said cores; a pair of magnets carried by each said plate one of said magnets saturating said group of cores and one saturating said interlock core when said plate is in said adjacent position; means for moving said plate from said first position to said second position including; means constraining one side of said plate causing said plate to move through an intermediate position at which said interlock core-saturating magnet is remote from said interlock core while said group of cores saturating magnet is adjacent said group of cores as said plate moves from said first position to said second position and for constraining said plate to move through said intermediate position as said support moves from said second to said first position; and means responsive to two or more of said interlock cores in an unsaturated state to decouple said plurality of groups of cores from said register.