US3557927A

US3557927A - Stenographic transcription system

Info

Publication number: US3557927A
Application number: US689079A
Authority: US
Inventors: Robert T Wright; Richard A Michals; Frank H Mozer; Ralph E Zumbahlen
Original assignee: Stenographic Machines Inc
Current assignee: Stenographic Machines Inc
Priority date: 1967-12-08
Filing date: 1967-12-08
Publication date: 1971-01-26
Anticipated expiration: 1988-01-26
Also published as: GB1252914A

Abstract

A computer transcription system for stenography is described. The system includes a conventional shorthand machine which has been modified to produce an electrical output. The modification is described in detail. A magnetic tape recorder which receives the electrical output of the shorthand machine is described in detail.

Description

United States Patent Inventors Robert T. Wright Libertyville;

Richard A. Michals, Skokie; Frank H. Mozer, Roselle; Ralph E. Zumbahlen, Chicago, 111.

Dec. 8, 1967 Jan. 26, 1971 Stenographic Machines, Inc.

Skokie, ill.

a corporation of Delaware Appl. No. Filed Patented Assignee STENOGRAPHIC TRANSCRIPTION SYSTEM 7 Claims, 16 Drawing Figs.

US. Cl 197 9, 197/1 1 B41j 3/26 Int. Cl Field of Search References Cited UNITED STATES PATENTS 7/1965 Stanley et al. l.

1,280,743 10/1918 Ireland H 197/9 1,913,831 6/1933 Clark l97/9X 2,319,273 5/1943 Sterling 197/9 2,390,414 12/1945 Ayres et a1... 197/9 2,593,371 4/1952 Watson 197/9 2,855,082 10/1958 Katz 197/9 2,912,090 11/1959 Holmes 197/9X 3,225,883 12/1965 Ayres 197/9X 3,260,340 7/1966 Locklar et a1 197/20X 3,305,062 2/1967 Kittredge 197/9X 3,372,865 3/1968 Pellegrini 197/9X 3,413,624 11/1968 Murdoch et a1. .1 197/19X Primary Examiner-Edgar S. Burr Attorney-Pendleton, Neuman, Williams & Anderson ABSTRACT: A computer transcription system for stenography is described. The system includes a conventional shorthand machine which has been modified to produce an electrical output. The modification is described in detail. A magnetic tape recorder which receives the electrical output of the shorthand machine is described in detail.

PATENTEB JAN26 [971. 55? 927 sum 1 0r 7 F/Gl.

F/GQ. 7 /7 N NUMERAL BAP 351m 95 f E @@U@@@@ IA/VE/VTORS I ROBERT 7T WRIGHT RICHARD A. M/CHALS FRANK H. MOZER RALPH 5. ZUM BAHLE/V 5y PENDLETON, NEUMA/V saw/.0 a W/LL/AMS ATTORNEYS PATENTEnJIIIzsIIIII 5 7 SHEEY 2 [1F 7 PAPER TAPE 7 3 /0 OPERATOR INPUT STENOTYPE MAGNETIC *I RECORDER TAPE MACH'NE OUT PUT MAGNETIC TAPE TAPE READER INTERFACE -CoM uTER PUT 6/0 FROM CARTRIDGE PARITY PLAYBAC'IT REGISTER /2 DEVICE 6623' DELAYED A A A A SHIFT REGISTER RESET I DATA I 6 5 4 3 2 CHANNEL A I D u; ij: I l 8 A I Q 65 A. 60/ II COUNT OF READY CLOCK I ecouNTER 22 CHANNEL Fig. /6

#vmvrms .SE/BOL D 8 WILLIAMS A TTOR/VE Y8 STENOGRAPI-IIC TRANSCRIPTION SYSTEM BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to stenographic recording and transcribing and particularly to computer transcriptions of phonetic records made by shorthand machines.

2. Description of the Prior Art Stenography is a widely used technique for recording the spoken word. The basic stenographic process includes two steps: (1) making a phonetic record of the speech being recorded by using a phonetic code, and (2) transcribing the phonetic record to a grammatical record. The stenographer, for example, performs both functions in taking and transcribing dictation. To insure reliability and efficiency in the recording process, and to simplify the transcribing process, shorthand machines are frequently employed to produce the phonetic record. Such machines are especially useful where the recording is made over a relatively long period of time, for example, in the courtroom or at a business meeting.

A widely used shorthand machine has a keyboard of 22 phonetically related characters which, to the skilled operator, provide the combinations necessary to record all English language words. The record produced by the machine is a paper tape on which the phonetic characters are printed. To record a word, or parts of a word, the operator presses an appropriate combination of keys and the machine prints the characters simultaneously on an interval of the paper tape. The tape is advanced one interval before each combination is recorded. A general description of this type of machine is given in US. Pat. No. 2,3l9,273 entitled Stenographic Machine which was issued to J. G. Sterling and assigned to the assignee of the present application.

The shorthand machine provides both reliability and economy in the recording process but the transcribing process, while improved through the use of a shorthand machine, remains time consuming. The operator must read back the paper tape containing the phonetic characters and make a corresponding grammatical record.

BRIEF SUMMARY OF THE INVENTION The present invention provides the means for reducing transcription time to an absolute minimum through the use of a computer. Briefly, the present invention includes a shorthand machine with an electrical output which provides the input information for a computer; the computer then performs the transcribing function. The computer compares the input characters from the shorthand machine, or from the phonetic record, with a grammatical reference and produces a grammatical output. In its simplest form, the grammatical reference is a dictionary" which relates all English language words to their phonetic or machine shorthand equivalents.

For ease of operation and flexibility of use, the shorthand machine may be coupled to a recorder, preferably a magnetic tape recorder, constructed according to the present invention. The recorder makes a record suitable for computer input. Briefly, a recorder constructed according to the present invention includes means for allocating fixed intervals along a recording medium, for example a magnetic tape, to phonetic words and for allocating fixed subintervals to individual phonetic characters. (The term phonetic words as used herein means a particular combination of phonetic characters which may form all or part of the phonetics of a spoken word. The term combination" as used herein is intended to include single as well as multiple elements. The term character as used herein means any representation of work construction including but not limited to letters of the alphabet.) The record is preferably made in binary bit form, that is a binary bit in a predetermined subinterval indicates the presence or absence of the particular phonetic character associated with the subinterval. By using the intervals and subintervals, both recording and reading are easily accomplished. The recorder may be an integral part of the shorthand machine, an integral part of the computer, or may be a separate unit. Also, the recorder itself may be used in applications not involving the transcription process. For example, the recorder may be used as a general input device for a computer or it may be used in connection with an output device, such as a typewriter, without using a computer.

In order to take advantage of the vast amount of research and development which has already been expended on shorthand machines, the present invention preferably employs a shorthand machine which is currently in use but which is modified to provide an electrical output. The electrical output is generated according to the present invention by employing a novel switching mechanism which may be readily incorporated into existing machines. In a preferred form, the switch includes a plurality of wires, each associated with a particular key on the keyboard and a contact assembly which the wires engage when the associated keys are depressed. The modification has distinct advantages in that it incorporates all the features of the shorthand machine which have been found most desirable.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a combination of shorthand machine and tape recorder constructed according to the present invention. FIG. 2 is a top view of the keyboard of the shorthand machine shown in FIG. 1. FIG. 3, which appears on the last sheet of drawings, is an overall block diagram of one embodimentof the present invention. FIG. 4 is a side view of a modification of a portion of a shorthand machine. FIG. 5 is an enlarged side view of a portion of FIG. 4. FIGS. 6 and 7 are front and bottom views respectively of the modification of FIG. 4. FIG. 8 is a side view of another modification of a shorthand machine. FIG. 9 is a top view of a tape recorder constructed according to the present invention. FIG. 10 is a bottom view of a tape recorder constructed according to the present invention. FIGS. 11 and 12 are side and plan views respectively of a commutator construction used in the tape recorder. FIG. 13 is a diagrammatic view of a tape produced by the tape recorder. FIGS. 14 and 15 are circuit diagrams of the circuits employed in the tape recorder. FIG. 16 is a block diagram of an interface device which provides an input for a particular type of computer.

DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows a shorthand machine 10 electrically connected to a tape recorder 11 constructed according to the present invention. The shorthand machine 10, except for modifications explained in detail below, is preferably a conventional machine manufactured by Stenographic Machines, Inc. The machine includes a keyboard 15 which operates a printing mechanism within a housing 16 for producing a paper tape record of the words recorded. The paper tape (not shown) is transported over a rubber platen 17 positioned at the back of the machine.

As shown more clearly in FIG. 2, the keyboard 15 of the shorthand machine 10 has 22 phonetically related characters 19. A numeral bar 20 is provided on the keyboard. When the numeral bar 20 is depressed along with one or more of the keys which have numerals as well as letters, then numerals rather than letters are printed. In using the machine, the operator depresses a certain combination of keys l9 representing the phonetic equivalent of the word to be recorded. The characters are then printed simultaneously on the paper tape. Each of the characters 19 of the keyboard 15 has a predetermined position across the paper tape and each character, therefore, always appears at exactly the same transverse position on the tape irrespective of the particular combination of keys which is depressed. For example, the paper tape record of the sentence, You should be able to read these short words." would appear as follows on the paper tape:

U S H U D B A B L T O R E D T H E S S H O R T \V O R DS The fixed spatial relationship between the various shorthand characters is taken advantage of in the present invention to produce a satisfactory record suitable for computer input.

As described in more detail below, the shorthand machine is modified to produce an electrical output which, in the preferred embodiment of the present invention, is coupled, through a cable 21, to the tape recorder 11 which produces a record suitable for computer input. As illustrated, the tape recorder 11 is of a size convenient for carrying by the operator; it may, for example, be contained in a case which is approximately the same size as the case used to transport the shorthand machine 10. Alternatively, the tape recorder 11 may be an integral part of the shorthand machine 10 or some other piece of equipment. The upper exterior of the tape recorder 1 1 supports two tape cartridge mounting brackets 22 for supporting a removable tape cartridge 23 of a conventional type. (In the embodiment described below, an AU- DIOPAC cartridge, broadcast model A, may be employed. Other tapes may, of course, be employed with suitable modifications.) A tape engaging lever 25 is mounted conveniently on the top of the machine as is a counter 26 for advising the operator of the amount of tape used. A battery pack 27 is conveniently located at the back of the machine.

A block diagram of the entire system of one embodiment of the invention is shown in FIG. 3. The operator uses the shorthand machine 10 to record the conversation or other spoken material. The shorthand machine 10 produces both a paper tape record and an electrical output which is fed to a recorder 11 constructed according to the present invention. Both the paper tape record and the recorder 11 are provided primarily for purposes of convenience. Either or both may be omitted in appropriate circumstances. The magnetic tape produced by the recorder 11 is read by a suitable tape reader 30 which produces an output supplied to a computer 31 through an interface unit 32. The computer 31 performs the function of transcribing the phonetic information to a grammatical record which is printed by a printer 33. The tape reader 30, computer 31 and printer 33 are all conventional and are not described in detail herein.

The block diagram of FIG. 3 is one example of a system constructed according to the present invention which has been found suitable for present purposes. However, modifications may be made. For example, the shorthand machine 10 may be constructed to produce an output which is fed directly to the computer 31 without the use of the intermediate equipment. Other modifications, which are by no means exhaustive, include an integrally constructed shorthand machine and recorder and a recorder which produces an output which is compatible with the particular computer thereby avoiding the interface unit 32.

A number of possible transcribing techniques are well within the present computer technology. One of the simplest techniques, for example, is to store all English language words in the computer 31 and to relate them to their phonetic equivalents which might, for example, appear at the output of the shorthand machine 10. Thus, when the computer receives the phonetic input U it will key a printer 33 to print the word YOU. While this type of program has some drawbacks, it is entirely within the present skill of the art and may be used in conjunction with the present invention. However, other more exact programs and translating systems are now available and may be used with the present invention. Thus, the computer may be programmed to observe certain grammatical rules, such as the rule that every sentence includes a subject and a verb, or the computer may be programmed as to correlations between various words used in speech. Such rules, for example, would enable the computer to print the word read instead ofred when it receives the phonetic input RED in the example given at the beginning of this application. The details of various programming systems, however, are not the subject matter of the present invention.

SWITCH ASSEMBLY FIGS. 4 through 8 show apreferred embodiment of the modification of the conventional shorthand machine which may be employed in the present invention. The modifications described are to a machine which is presently available from Stenographic Machines, Inc. but similar modifications can be made on any shorthand machine.

Referring particularly to FIG. 4, each of the keys 19 of the conventional machine 10 is connected through a lever 41 to the type drive mechanism. Upper motion of the levers 41 is limited by a top stationary felt pad 42 which contacts the upper edge 43 of each lever 41. A lower, movable, pad 45 contacts the bottom 46 of each lever 41 and is connected to the paper drive mechanism (not shown) of the machine. The pads 42, 45 are provided at the points of contact to provide noiseless operation.

Each of the levers 41 is pivotally mounted on a shaft 47 which extends across the machine. The end 50 of each lever 41 contacts one end 51 of a bellcrank having a center portion 52 rotatably mounted on a shaft 53 and a second end portion 54 pivotally connected to a type bar 55. The bellcrank is biased with a return spring 56 attached to the stationary portion 57 of the machine 10. Each type bar 55 supports one or two pieces of type 60, 61 depending upon whether the associated key 19 is used to print a numeral and a phonetic character or just a phonetic character. When a key 19 is depressed by the operator, the upper piece of type 61 contacts the paper tape (not shown) which is fed between the type and a rubber cylindrical platen 17. When the numeral bar 20 (FIGS. 1 and 2) is depressed with one of the keys 19 containing a numeral, the type bar 55 is raised slightly, through a mechanism which is not illustrated, so that the lower piece of type 60 engages the paper. To this point in the description, the construction of the key assembly is conventional and is typical of the machine presently being sold by Stenographic Machines, Inc. The modification of the machine will now be described.

Referring to FIGS. 4 through 7, the switch assembly includes a switch keeper 70 which is connected to a mounting bracket 71 rotatably mounted on the shaft 47. The switch keeper 70 supports a plurality of wires 73 which form the movable portions of the various key switches. An insulating block 74, which is rigidly connected to the mounting bracket 71, supports the common contact bar assembly 75. The ends of the wires 73 opposite the switch keeper 70 are connected through a small insulating tube 78 to a pull rod 79 which extends through the insulating block 74 and engages a notch 80 cut in the end 51 of the key lever 41. When the key 19 is depressed, the key lever 41 pulls the wire 73 into engagement with the common contact bar assembly 75. Preferably, the wires 73 and the bottom of the contact bar 75 are made of a high conductivity, noble metal alloy to insure reliable operation. A metal which has been found suitable is PALINAY 7" alloy which is sold by J. M. Ney Co. Typically, the wires 73 are 0.020 inch in diameter.

As shown in FIG. 5, an adjusting set screw is threaded through a stud 86 mounted in the spool casting 87 of the machine. The set screw 85 contacts the top of the mounting bracket 71 which is rotatable about the key lever shaft 47. The entire mounting bracket 71 is biased by a spring 89 connected to the spool casting 87. The set screw 85 allows for adjustment of the relationship between the common contact bar assembly 75 and the contact wires 73. Thus, as the set screw 85 is rotated into engagement with the mounting bracket71, the bracket 71 rotates clockwise about the shaft 47. This rotation causes the common contact bar assembly 75 to move farther away from the rest position of the switch wires 73 which remain relatively fixed because the pull rod 79 and key lever 41 do not move.

The switch assembly described above operates to provide a contact between one or more of the wires 73 and the common contact bar 75 when the keys 19 are depressed. Each of the wires 73 is individually connected to a circuit in the tape recorder 11 through a conductor connected to the wire extension 90 on the right-hand side of the switch keeper 70. The common contact bar 75 is also connected to the tape recorder circuit. When a key 19 is depressed, the wire 73 associated with that key 19 completes a circuit to indicate that the key has been depressed.

In the case of a key which has both a numeral and a phonetic character, more is required than merely completing the circuit associated with the wire 73 to indicate the intent of the operator. For this reason, a separate switch is provided on the numeral bar assembly of the machine.

A suitable switch 100 for the numeral bar assembly is shown in FIG. 8. The numeral bar is integrally connected with a lever 101 which is pivotally mounted about a shaft 102. As explained above, when the numeral bar 20 is depressed, each of the type bars is raised so that the lower piece of type will engage the paper on the platen 17. A two contact switch is securely attached to the stationary portion 104 of the machine 10. The lower contact 105 engages a bar 106 mounted on the numeral bar lever 101. Thus, as the numeral bar 20 is depressed, this switch 100 is closed. Both contacts of the switch 100 are electrically connected to the tape recorder.

TAPE RECORDER FIG. 9 is a top view of a preferred embodiment of the tape recorder 11 constructed according to the present invention. The recorder 11 includes a mounting plate 110 which is attached to a suitable case 11 1 for portable transportation. The case 111 contains a battery supply 27 and an electrical cable 21 for attachment to the shorthand machine 10. Two cartridge mounting brackets 22 are attached to the mounting plate 110 to enable a conventional tape recording cartridge 23 to be placed in the machine 11 for recording the stenographic information. A bracket 115 for mounting a magnetic recording head 116 is also attached to the plate 110. The bracket 115 includes two extensions 117 for accurately engaging the tape cartridge 23. The magnetic recording head 116 is mounted between these two extensions 117 to engage the tape 118 within the cartridge 23.

A capstan 120 for driving the tape 118 extends through the mounting plate 110. A driving connection between the capstan 120 and tape 118 is insured by a rotatable rubber wheel 121 which may be moved into and out of engagement with the tape 118 by a lever 25 mounted on one side of a cartridge bracket 22. The cartridge mounting and tape drive elements described above are conventional and in themselves form no part of the present invention. The magnetic recording head 116 is a conventional two-track head and may be, for example, a commercially available Nortronics PB2H7K-N7 model. The head alignment bracket 115 is also conventional. A conventional counter 26 is mounted in the machine 11 for monitoring the extent of the tape recorded. The drive motor for the entire machine is also attached to and extends above the mounting plate 110.

A bottom view of the tape recorder 21 is shown in FIG. 10. As already noted, the mounting plate 110 supports the drive motor 130 for the entire tape recorder mechanism. The motor drives a wheel 150, which is rotatably mounted on a shaft 151 supported by the mounting plate 110, through a flexible band 152. The rotatable shaft 151 associated with the wheel drives a larger wheel 153 through a second flexible band 154. A third smaller wheel 155 drives the counter mechanism 26 through a third flexible band 157. The shaft 159 associated with the large wheel 153 is rotatably mounted in the plate 110 and acts as the capstan which drives the tape.

The details of the drive system just described may, of course, vary widely. An example of suitable specifications will be given. The drive motor 130 may be a Mitsumi Electric Co. model MlSN-l, 8 volt, DC permanent magnet motor with a rated torque of 10 gram centimeters at 3000 rpm. and a starting torque of 40 gram centimeters. The drive system ratios, in a typical machine, are a 7 to 1 reduction from the motor 130 to the first wheel 150 and a 7 to I reduction from the first wheel 150 to the second wheel 153.

The rubber tape engaging wheel 12] shown in the top view of FIG. 9 is mounted on a shaft 122 (FIG. 9) which is connected perpendicularly to a rotatable shaft 123 extending across the bottom of the machine. The shaft 123 is rotated through a spring loaded drive mechanism 124 connected to the lever 25 (FIG. 9). Thus, by moving the lever 25, the wheel 121 is moved into or out of engagement with the tape 118.

The mounting plate 110 also serves as a support for various electrical elements, some of which are shown in FIG. 8. Thus, two fuses 160, a transformer 161, and the electrical circuit boards 162 are supported by the mounting plate 110. The fuses and transformer 161, together with the battery 27, are part of the power supply circuit for the tape recorder.

As illustrated in FIG. 11, the wheel 150 which is directly driven by the motor 130 supports two electrical wiper arms 170, mounted in a tubular holder 171. The two wiper arms, 170, which are electrically connected together, engage an electrical commutator 175, the details of which are illustrated in FIG. 12. The! commutator includes a first set of similar contacts which are electrically isolated from one another. A second set of contacts 181 is interposed between the contacts of the first set. The contacts 181 of the second set are electrically connected to one another by a band 182 which extends around the outer periphery of the commutator 175. A circular conductive member 186 is positioned within the pattern formed by the two contact sets. As the wheel 150 is rotated, one of the two wiper arms 170 engages the inner circular conductive member 186 while the other wiper arm engages the various

electrical contacts

180, 181 in the outer pattern, one at a time. Thus, as the wheel 150 rotates, electrical connections are successively made between the inner circular member 186 and the

contacts

180, 181 in the outer pattern. The inner circular member 186 is electrically connected to ground or to some point of reference potential, and the

contacts

180, 181 in the outer pattern are connected to the recording portion of the electrical circuit as described in detail below. Each of the contacts 180 of the first set corresponds to one of the phonetic character keys 19. Each of the contacts 181 of the second set provides a clock pulse which is used in the computer processing equipment. Electrical connections from the commutator 175 to the electrical circuit are made by wires 190 mounted underneath the commutator 175 which are formed into a cable 21 after they pass through a bracket 191 (FIG. 10) attached to the mounting plate 110.

The commutator 175 may be a printed circuit with the various contacts being formed of a NEYORO G" alloy sold by the .I. M. Ney Co. The two wiper arms 170 may be made of PALINAY 7" alloy sold by the same company.

FIG. 13 illustrates the magnetic pattern produced by the embodiment of the tape recorder being described. The view illustrated in FIG. 13 shows the tape 118 moving to the right with the two-track magnetic head 116 shown in dotted lines behind the tape.

The lower gap 150 in the head 116 records a series of 23 binary clock bits for each interval of the tape, that is for each length of tape which corresponds to a single depression of a combination of keys. The upper gap 151 in the head 116 records a series of binary data bits which provide a magnetic record of the particular combination of keys depressed. The data bits are in a fixed spatial relation in the word interval defined by the clock bits. The particular orientation of bits is not important provided the orientation is known. A suitable orientation, for example, would place the bit corresponding to the first S on the keyboard over the first clock bit, the bit corresponding to the first T over the second clock bit, and so forth as follows: 1

STKPWHRAO* EU FR PBLGT SDS 1234567891011ll2l314151617l81920212223 Once this spatial relationship is established, there is little difficulty in recording and processing the data. The computer is programmed with this particular spatial relation and it therefore knows, for example, that if a recording has been made above the 14th clock bit in a particular word interval, then an R appears in that interval, and that the R is the second R of the keyboard.

The 23rd position in the word interval, i.e., the position above the 23rd clock pulse, indicates the presence or absence of a numeral bar depression in the word interval. Referring again to FIG. 2 for a moment, note that the numeral 2 is on the same key as the initial T. Therefore, if the recorded pattern on the tape has a bit above the second clock bit, i.e., the space corresponding to the initial T, and a bit above the 23rd clock "bit, then the computer knows that the numeral 2 appears in the particular word interval.

A fixed spatial relation between data bits and word intervals provides a very advantageous recording technique. The actual recording of the various bits may, of course, be accomplished either serially or in parallel; in the presently described embodiment, serial recording is employed.

CIRCUIT DESCRIPTION FIGS. 14 and 15 illustrate the circuitry of the tape recorder. The interconnections between these two circuits are illustrated by circled capital letters.

Referring to FIG. 14, a plurality of input terminals 200 are provided for connection to the shorthand machine There are a total of 23 inputs 200, however, only eight have been indicated for the sake of simplicity. 22 of the inputs 200 are connected to the 22 wire switches 73 in the shorthand machine 10; one of the inputs 200 is connected to one of the contacts of the switch 100 which is associated with the numeral bar lever 101. A 24th input 207 is provided for the common contact bar 75 of the switch assembly and the other contact of the switch 100.

The inputs 200 are connected through a plurality of diodes 201 to memory capacitors 202. The terminals 200 are also connected through an OR gate, comprising a plurality of diodes 203 all connected to a resistor 205 at their anodes, to the base 209 of a PNP transistor 210. The input terminals 200 are also connected through individual resistors 211 to the emitter 215 of the transistor 210. A decoupling capacitor 216 is connected between the bank of resistors 21! and the bank of diodes 203.

The memory capacitors 202 are connected together at one end to form the data output (A) of the memory circuit. (The data output (A) is connected to the common point or ground through a diode in the data circuit of FIG. 10.) The other sides of the capacitors 202 are connected to the data contacts 180 of the commutator 175 contained in the tape recorder. The th and 23rd contacts are connected to th respective capacitors 202 through two isolating

diodes

300 and 301 and are connected to other circuit points through two

other diodes

302, 303.

Referring now to the transistor circuit of the memory circuit, a PNP transistor amplifier 210 with its emitter 215 connected to the point of common potential through a zener diode 220 which develops a reference voltage, receives the input signal from the OR gate 203 as described above. A diode 218 is connected between the base 209 and emitter 215 for positive pulse bypass protection. Two

resistors

222, 223 connected to the transistor 210 and the power supply (not shown) provide the necessary bias for proper operation of the circuit. A load resistor 225 provides the output current path for the amplifier.

The collector 230 is connected through a network including a capacitor 231 and a resistor 232, and through a diode 34 to a one-shot multivibrator including two

transistors

235, 236. The collector 238 of the first transistor 235 is capacitively coupled to the base 240 of the second transistor 236 of the multivibrator through a capacitor 241 and a resistor 242. The collector 260 of the second transistor 236 is coupled to the base 261 of the first transistor 235 through a resistor 262 and a diode 263. A capacitor 267 is connected between the diode 263 and the common point of ground.

The multivibrator formed with the two

transistors

235, 236 is normally off, i.e., both

transistors

235, 236 are not conducting. The multivibrator is turned on by a negative pulse applied through the diode 263 to the base 261 of the first transistor 235. The negative pulse drives the transistor 235 into conduction; the resulting positive going pulse at the collector 238 of the transistor 235 is coupled through the capacitor 241 and resistor 242 to the base 240 of the transistor 236, thereby turning that transistor 236 on. The collector 260 of the transistor 236 is then negative as is the cathode of the diode 263 to provide regenerative feedback for the transistor 235. Also, the capacitor 267 charges to maintain a negative voltage at the cathode of the diode .263, thereby tending to keep the transistor 235 in an on state after the negative pulse has passed. The time constant of the circuit is determined by the charging rate of the other capacitor 241. As this capacitor 241 charges, the voltage at the base of the transistor 240 increases and the transistor 236 is eventually shut off.

A diode 303 is connected from the 23rd contact of the commutator 175 through a charged capacitor 233 to the diode 263 connected to the base 261 of the first transistor 235. When the 23rd contact is grounded, a positive pulse appears at the diode 263 to render it nonconducting, thereby turning off the multivibrator. Thus, it will be seen that the multivibrator may be turned off by a pulse from the 23rd contact or through its own operation. The normal operation of the multivibrator is that it is turned off by the pulse from the 23rd contact of the commutator 175. For this reason, the time constant of the multivibrator circuit is considerably longer than the expected period of operation of the commutator. Generally, a time constant of approximately milliseconds is sufficient. I

A fourth transistor 287 is part of the memory capacitor charging circuit; when one of the key switches is closed, the associated memory capacitor 202 charges through the transistor 287. The base 288 of the transistor 287 is coupled to the multivibrator to prevent the next stroke from charging the memory capacitor during the time the previous stroke is being recorded (sometimes known as overstriking). When the transistor 235 is conducting, the base 288 of the transistor 287 is near the ground potential and the transistor is shut off. Thus, the memory capacitors 202 cannot charge during this interval even if the operator should, by accident, depress some of the keys 19.

The operation of the memory circuit shown in FIG. 12 can be described as follows. Prior to the first depression of keys 19 by the operator of the shorthand machine 10, all the transistors of the memory circuit are in an off condition, that is they are not conducting. When the operator depresses one or more of the keys 19 on the shorthand keyboard 15, the memory capacitors 202 associated with the depressed keys 19 are charged to the negative supply voltage through the diodes 201, the switches in the shorthand machine and the transistor 287. At the same time, the negative voltage at the emitter of the transistor 287 is applied through the diodes 203 to the base 209 of the first transistor 210. This negative voltage turns this transistor on and its collector 230 goes to the reference voltage determined by the zener diode 220. The capacitor 231 connected to the collector 230, which was charged with its negative side at the collector 230, discharges when the transistor 210 begins to conduct.

When the operator releases the various keys 19 of the shorthand machine 10, the negative voltage is removed from the base 209 of the transistor 210 and the transistor 210 stops conducting, thereby causing a relatively large negative voltage to appear at its collector 230. The negative voltage is coupled through the capacitor 231 and the diode 234 to the diode 263 in the base circuit of the transistor 235. The transistor 235 is therefore turned on. By the regenerative action explained above, transistor 236 is also turned on and holds the transistor 235 in a state of conduction. Also, as explained above, the base of transistor 287 goes to approximately ground potential, thereby turning off the transistor 287.

As explained in detail below, the relatively positive voltage which appears at the collector 238 of transistor 235 when it is conducting operates to start the motor 130 which drives the commutator 175. When the commutator 175 reaches the 23rd data contact, a positive pulse is coupled through the capacitor 233 to back bias the diode 263 in the base circuit of transistor 235. This immediately turns off the transistor 235. As explained above, this action occurs prior to the inherent turn-off time of the one-shot multivibrator formed by the two

transistors

235 and 236.

The circuit of FIG. includes both the motor control circuitry and the clock and data circuitry. The motor control circuitry receives two inputs (B and C) from points in the circuit shown in FIG. 12. The input labeled (B) is taken from the collector of the transistor 235 in the FIG. 12; the other input (C), is taken from a data contact on the commutator 175, nominally the th contact. While the 20th contact is illustrated by way of example, it should be noted that this is merely a nominal position. The (C) signal provides the turn-off signal for the motor 130 and the signal should be generated sufficiently late in the commutator cycle to prevent the commutator from stopping before it reaches the last contact, i.e., the 23rd contact, and also before it reaches the first contact. For the type of motor preferably employed in the tape recorder, this position will be close to the 20th contact of the commutator, but the exact position is best determined experimentally.

The first input (B) to the motor control circuit is coupled through a resistor 320, a first diode 321, a capacitor 322 and a second diode 323 to the base 324 of a first transistor 325. A parallel resistor 327-capacitor 328 combination provides a bias for the first diode 321. A resistor 330 provides bias for the transistor 325. The second input (C) is connected through a resistor 331 to a midpoint of a resistive divider network 333 coupled between ground and the emitter 335 of the first transistor 325. The midpoint of the divider network 333 is coupled through a capacitor 337 to a resistor 336 connected in the collector circuit of the first transistor 325 and to the base 339 of a second transistor 340. The emitter 343 of the second transistor 340 is connected to ground while the collector 344 is connected to the field windings of the motor 130.

A third transistor 350 is connected across the motor 130 field windings. The base 351 of the third transistor 350, which is biased with a suitable resistor 370, is coupled through a resistor 353 and the collector-emitter path of a fourth transistor 360 to ground. The base 361 of the fourth transistor 360 is connected to the emitter 365 of a fifth transistor 366. The base 367 of the fifth transistor 366 is connected through a network to the collector 344 of the second transistor 340. The network includes a capacitor 375 connected in series with two series connected resistors 376, 377 with a diode 378 connected between the two resistors 376, 377 and ground. A bias resistor 380 is connected between the base and emitter of the fifth transistor 360.

The operation of the motor control circuit is as follows. All the

transistors

325, 340, 350, 360, 366 of the motor control circuit are normally nonconducting in order to conserve power. The (B) input is at the negative supply voltage. The capacitor 322 in the (8) input coupling network is charged with its most negative side closest to the (B) input.

Assume that the operator of the shorthand machine depresses a certain combination of keys 19 on the keyboard 15 to make a recording. This action, of course, closes certain switches in the shorthand machine. Closing of the switches has no effect on the motor control circuit whatsoever. When all the depressed keys are released, however, the (B) input goes to ground potential and a positive pulse is coupled through the capacitor 322 and diode 323 to the base 324 of the first transistor 325 of the flip-flop, thereby turning this transistor on. The on state of the first transistor 325 causes the second transistor 340 to turn on. Since the motor is in the load circuit of the second transistor 340, current is conducted through the motor 130 and the motor 130 accelerates, thereby starting rotation of the commutator 175. The conduction of the second transistor 340 maintains the first transistor 325 in a conducting state even after the positive pulse is removed.

The motor control circuit is now unaffected until it received the (C) input when the commutator reaches the appropriate contact, nominally the 20th data contact on the commutator. When this position is reached, a positive pulse is coupled through the capacitor 337 to the base 339 of the second flipflop transistor 340, which is thereby turned off. Since the second flip-flop transistor 340 is turned off, the first transistor 325 can no longer conduct and it also is turned off. The collector of the second transistor 340 goes negative and a large negative pulse is thereby coupled through the capacitor 375 to the base of the transistor 366. The effect of this is to turn on

transistors

366, 360 and 350, thereby shortcircuiting the motor 130, causing rapid deceleration.

The clock data record circuit is also shown in FIG. 15. The conducting band 182 which joins all the clock contacts 181 on the commutator is coupled through a network to the base 393 of a first transistor 380 of the clock circuit. The coupling network includes a resistor 381, a capacitor 382 connected to ground, a second resistor 383, a diode 384 and a capacitor 385. The cathode of the diode 384 is connected to a noise suppression capacitor 387 and through a resistor 388 and a diode 389 to a point (D) in the memory circuit. A capacitor 390 connected to diode 390 suppresses noise pulses picked up from the motor. A capacitor 390 charges to back bias the diode 389.

The bias network for the first transistor 380 includes the parallel combination of a resistor 391 and capacitor 392 connected between the negative source and the base 393. Two other series connected

resistors

394, 395 are connected between the collector 396 and ground.

The second transistor 400 of the clock circuit forms a flipflop with the first transistor 380. Thus, the collector 412 of the second transistor 400 is connected through a resistor 405 to the base 393 of the first transistor 380. Also, the base 407 of the second transistor 400 is connected through a diode 410 to the midpoint of the

collector bias resistors

394, 395. A load resistor 41 1 is connected between the negative supply and the collector 412 of the second transistor 400.

The data input (A) from the memory capacitors 202 is coupled through a capacitor 420 and diode 422 to cut off the current supplied to the base 407 of transistor 400 from the collector 396 of transistor 380. The collector 412 of transistor 400 will now go negative, removing the turn on current to base 393 of transistor 330, causing it to turn off.

The flip-flop formed by the

transistors

380, 400 produces an output at the collector 412 of the second transistor 400. This output is connected through a diode 450 and a resistor 45] to one side 452 of the magnetic winding 453 of the clock recording head. The other side 454 of this winding 453 is connected to the positive side of a zener diode 455 which provides a fixed negative reference for the clock winding 453. When the clock winding 453 is not recording clock pulses, current flows through the winding 453 from the negative supply, through two resistors 451, 457 and the zener diode 455. When the winding 453 is recording, i.e., when the second transistor 400 of the flip-flop is conducting, current flows in the opposite direction in the clock winding 453 through the diode 450 connected to the collector 412 of the second transistor 400.

The data record circuit is similar tothe clock record circuit. The data output (A) from the memory capacitors 202 is coupled through a network to the base 481 of a third transistor 480 of the clock data circuit. The network includes the series combination of a resistor 482, two

capacitors

483, 484 and diode 485. A connection is provided between the reference point (X) in the memory capacitor circuit and the diode 485 in the network. This connection provides a reference point for biasing the diode 485. Thus, when a large positive pulse is applied to the data input (A), the diode 485 will conduct, However, when a less positive pulse, that is a pulse resulting from the commutator triggering a memory capacitor associated with a key which was not depressed, the diode 485 will not conduct. A resistor 491 is provided for charging the first capacitor 483 of the network and a filter capacitor 490 is provided for any transient pulses.

The construction of the data record circuit is similar to the clock circuit already described. Thus, the third transistor 480 of the clock data circuit forms a flip-flop with a fourth transistor 487 and the output of the fourth transistor 487 is connected through a diode 500 to the data recording winding 520. Since the construction of the circuit has already been described above with reference to the clock circuit, it will not be repeated here.

The operation of the clock data record circuit can be described as follows. When the circuit is in rest position, all the transistors of the circuit are nonconducting. Nothing happens in this circuit until the last key 19 of a set of depressed keys is released by the operator. As explained above, this release starts the motor 130 and applies a negative voltage to point (D), causing diode 384 to go negative. When the first of the clock segments 181 is contacted by the commutator 175 and thereby grounded, then a large positive pulse is coupled through the capacitor 385 to the base 393 of the first transistor 380, thereby turning the transistor 380 on. The second transistor 400 is turned on due to the conduction of the first transistor 380. The conduction of the second transistor 400 provides the necessary record current path for the clock record winding 453 which then records the clock pulse.

When the commutator leaves the first clock segment and reaches the first data segment, a large positive pulse is coupled through the capacitor 420 at the (A) terminal to the diode 410 in the base circuit of the second flip-flop transistor 400, thereby back biasing and turning the transistor 400 off. Conduction of the second transistor being terminated, the clock record head 453 begins recording in the reverse direction.

The effect of the commutator 175 reaching the first data contact on the data record circuit depends upon whether the memory capacitor 202 associated with that contact is charged to the level of the negative supply or charged to the small reference value provided by the zener diode 220 in the memory circuit. If the capacitor 202 is merely charged to the small reference value then, while a small positive pulse will appear at the data inputs (A), the magnitude of the pulse will not be great enough to turn on the diode 485 coupled to the base 481 of the transistor 480. The transistor 480, therefore, will not conduct. The magnitude of even the small reference pulse, however, is enough to terminate conduction of the diode 410 in the clock record flip-flop. Thus, the clock record circuit stops conducting on the occurrence of every data bit.

if the memory capacitor 202 associated with the data contact is charged to the full negative supply, then a large positive pulse will be applied to the data input (A) and the diode 485 will conduct and drive the first transistor 480 of the data record flip-flop into conduction. The operation of this record circuit is then similar to the clock circuit. The second transistor 487 of the flip-flop is turned on providing a conduction path through the diode 500 to the data record head 520 and a data pulse, is, therefore, recorded.

After the commutator 175 leaves the first data segment and arrives at the second clock segment, the clock circuit is again turned on as described above. When the second transistor 400 in the clock record circuit begins to conduct and goes to essentially ground potential, a large positive pulse is thereby coupled through the capacitor 495, which is coupled through a diode 496 to the diode 489 in the base circuit of the second transistor 487. This large positive pulse turns off this transistor 487 to stop the data recording.

The operation of the clock record and data record circuits continue as described above until the last data segment is contacted by the commutator. In order to prevent continuous recording in the event the data record head 520 is turned on by the last data segment, a 24th clock segment (CL24) is provided on the commutator. This segment is not connected to the clock record circuit, but it is coupled to the diode 489 in the base circuit of the second transistor 487 of the data record flip-flop. When the commutator 175 reaches the CL24 contact, the data record flip-flop will be turned off and the head 520 will stop recording.

COMPONENT VALUES In a typical construction, the component values for the various circuits are as follows:

All PNP transistors are either 2N3906 or 2N4403. All NPN transistors are either 293904 or 294401. Exceptions are indicated below. All diodes are Sylvania D6623A or as noted below. All transistors are one-fourth watt except as indicated below.

MEMORY CIRCUIT Resistors, ohms:

R22522K; R232K; R23822K; R239470K; R242-100K; R247-47K; R2624.7K; R2822.2K; R283-IK; R284-22K; R287-10K. Capacitors, microfarads:

C202.15; C216.02; C231.033; C233.005; C241 1/15; C267.0O5. Zener diode 220, Model #lN4731.

MOTOR CONTROL CIRCUIT Resistors, ohms:

R3201K; R32747K; R330-10K; R331-10; R332-1K; RR333-100K; R336- (1 watt); R342- 470; R353-220 (1 watt); R368-10K; R3691K; R370 10K; R371-10K; R372100; R376-1K; R377-47K; R380-22K.

Capacitors, microfarads:

C322.005; C328.O05; C337.15; C3751/15. Transistors:

TR340-2N3740; TR350-2N4401.

CLOCK DATA RECORD CIRCUIT (Duplicate components not specified where values are obvious.)

Resistors, ohms:

11381-470; R383-1K; R38822K; R3912.2K; R394-10K; R3952.2K; R40510K; R4114.7K; R421- 47K; R42710K; R4512.2K; R4572.2K; R4582.2K; R479-IK; R482-1K; R486-lOOK; R491-10K; R497- 47K; R518-100; R5192.2K. Capacitors, microfarads:

C382.005; C385.O05; 0387-.005; C390-.02; C392.005; C420.005; 0483-.005; C484.005; C490- .005; 0494-100/25; C495-.005.

Zener diode 455, Model #1N4734.

OVERALL CIRCUIT OPERATION The interrelated operation of the various tape recorder circuits can be described by the following timing sequence where the various ts indicate successive points in the cycle of operation. For a more detailed description of specific circuit operation, refer to the preceding discussion.

t Operator depresses keys.

This causes the following effect:

a The diodes 201 associated with the depressed keys are connected to the negative power supply through the transistor 287. The associated memory capacitors 202 then charge to the negative supply voltage.

t Operator releases keys.

This causes the following effects:

a. The multivibrator in the memory circuit (transistors 235,

236) is turned on.

b. Transistor 287 is turned off to prevent the next stroke from charging the memory capacitors before the previous stroke is completed.

c. The motor 130 is started.

t -Motor drives commutator to first clock segment.

This causes the following effect:

a. The flip-flop in the clock circuit (transistors 380, 400) is turned on and a clock pulse is recorded on the tape.

t.,-Commutator reaches first data segment.

This causes the following effects:

a. If the memory capacitor 202 associated with the first data segment is charged because the associated key 19 was depressed, than a large positive pulse is coupled to the base 481 of transistor 480, thereby turning on the flipflop circuit and causing the data winding 520 to record. if the memory capacitor 202 is not charged to a large potential, then the small positive pulse applied to the data record input is insufficient to forward bias the diode 485.

b. A positive pulse, which is large or small depending on the charged condition of the memory capacitor 202, is coupled through the capacitor 420 to back bias the diode 410 of the flip-flop, thereby stopping recording of the preceding clock pulse.

t -Commutator reaches next clock segment.

The effects here are the same as at 1 with one addition.

a. The positive pulse appearing at the collector 412 of the transistor 400 is coupled through the capacitor 495 to the data record flip-flop to terminate recording of the preceding data pulse.

t -After the commutator leaves the second clock segment,

the operation continues as described in t and t until the commutator reaches the th data segment.

r Commutator reaches 20th data segment.

This causes the following effects:

a. A positive pulse is coupled to the input (C) of the motor control circuit. Power is removed from the motor 130 and short-circuited by transistor 350 to cause its rapid deceleration.

r Commutator reaches 23rd data segment.

This causes the following effects:

a. The same effects as at 2., occur.

b. A positive pulse resets the multivibrator in the memory circuit.

r,,-Commutator reaches 24th clock segment.

This causes the following effect:

a. A positive pulse is applied to the CL24 input of the data record circuit to terminate recording the previous data pulse. t,06 The above will repeat when the operator next depresses the keys.

FIG. 16 is a block diagram of an interface unit which converts the output from the conventional tape reader for the tape recorded on the tape recorder described above to a form which is suitable for input to the particular type of computer being used or with an intermediate tape recorder which is compatible with the computer. The particular circuit shown in FIG. 13 generates an output which is compatible with an IBM 360 computer. This output in most cases will be supplied to a conventional IBM compatible tape recorder. Briefly, the unit converts the serial information from the tape to a series of seven bit words. Six of the bits contain data, the seventh is a parity bit.

A conventional tape play-back unit (not shown) produces two output channels 600, 601 derived from the tape recorded on the recorder described above. The data channel 600 is supplied to a six bit shift register 603 which is operated, i.e., shifted, by the clock pulse received from the clock channel input 601. A count of six counter 60S produces an output to open a plufality of gates 606 when six bits have been shifted into the shift register 603. A gate 606 is associated with each of the six outputs of the shift register 603. A conventional parity register 610 receives each of the bits and determines the parity of the six bits in the register 603. The parity register 610 supplies the seventh output of the signal supplied to the IBM compatible tape recorder. The parity register 610 is reset shortly after the sixth bit is detected by the counter 605. Thus, a delay unit 6112 is provided between the counter 605 output and the parity register 610.

As soon as six bits have been received and stored by the shift register 603, the counter 605 generates a trigger pulse which opens each of the seven gates 606 to provide a parallel output for the IBM compatible recorder. The counter 605 also generates a ready signal which is supplied to the IBM compatible recorder, or the computer, to indicate the condition of the shift register 603. Thus, the parallel input from the tape recorder described above is converted to a seven bit parallel output suitable for use by a compatible tape recorder.

The above detailed description of the various elements of the present invention is not intended to be at all limiting as to the scope of the invention. The invention itself is defined by the following claims.

We claim:

1. A recording system comprising:

a. means for generating input information representing words or parts of words, the representations being selected from a font of characters, said information being in the form of a plurality of sets of binary bits, the presence or absence of a character in said combination being represented by the state of its corresponding binary bit in said set;

b. a recording medium;

c. first recording means associated with said medium for recording a plurality of identical reference intervals on said recording medium, each interval having a plurality of subintervals equal to the number of binary bits in each said set, one subinterval for each one of the characters of the font, and wherein each of said subintervals defines a single binary bit, and therefore a single character, on said recording means; and

d. second recording means coupled to said generating means and associated with said recording medium for recording the binary bits of said input information within the appropriate binary intervals recorded on said medium by said first recording means.

2. The recorder as claimed in claim 1 wherein said recording medium is a magnetic tape having first and second parallel tracks, and said first recording means includes a first magnetic recording head in recording relation to said first track, said recorder further including means for transporting said tape past said first head in incremental lengths which define said intervals, and means coupled to said first recording head for recording clock pulses along said first track of said tape, said clock pulses defining said subintervals.

3. The recorder as claimed in claim 1 wherein said second recording means includes a second recording head for recording said binary bits along said second track and wherein said input means includes a plurality of binary storage elements, one for each of said characters, means for sequentially coupling said storage elements to said second recording head, means for controlling said coupling means in synchronism with said tape transport control means and said clock pulse recording means.

4. The recording system of claim 1 wherein said means for generating input information includes a shorthand machine having a keyboard comprising a set of keys wherein numerals, words or parts of words correspond to keys or combinations of keys, said machine including a set of binary switches, each switch of said set being coupled to a different key whereby the binary states of the switches in said set at each stroking of said keyboard correspond to the keys or combinations of keys which have been stroked and contain binary information designating the word or numeral information of said stroke, and further including a plurality of binary storage elements, one for each of said binary switches, and means for coupling the storage elements to said second recording means after the last key of a stroke has been released.

5. A 'stenographic system as claimed in claim 4 wherein said machine includes a supporting means, and said keys move relative to said supporting means, said switches comprising a plurality of cantilevered wires, each rigidly supported at one end by said supporting means and mechanically coupled at another portion to said keys, whereby said wires are displaced when said keys are depressed, a common contact bar mounted on said supporting means at a position to contact said wires when they are displaced by depressing said keys, a source of electrical energy, and electrical circuit means for completing a circuit through said source of electrical energy, said switches and said storage means.

6. A stenographic system as claimed in claim 5 wherein said keyboard further includes a numeral bar and some of said keys are used to record numerals when said numeral bar is depressed therewith, and further including a switch associated with the numeral bar and actuated thereby.

7. A stenographic system as claimed in claim 5 further including means for moving said wires relative to the contacts for said wires for purposes of adjustment.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. ,557,9 7 Dated January 26, 1971 Robert T. Wright, Richard A. Michals, Frank H. Inventor(5) MOZer and E. ZumBahlen It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 7, line 33, "22" should be --Twenty-two-- Column 7, line 56, "th" should be --their-- Column 7, line 72, "diode 3n" should be --diode 23M Column 8, line. 5, "of" should be --or-- Column 13, line 33, "11 should be --1;

Column 13, line 50, "t O-6" should be --t Signed and sealed this 6th day of July 1971.

(SEAL) Attest:

EDWARD M.FIETCHER,JR. WILLIAM E. SCHUYLER, JR. Attesting Officer Commissioner of Patents

Claims

1. A recording system comprising: a. means for generating input information representing words or parts of words, the representations being selected from a font of characters, said information being in the form of a plurality of sets of binary bits, the presence or absence of a character in said combination being represented by the state of its corresponding binary bit in said set; b. a recording medium; c. first recording means associated with said medium for recording a plurality of identical reference intervals on said recording medium, each interval having a plurality of subintervals equal to the number of binary bits in each said set, one subinterval for each one of the characters of the font, and wherein each of said subintervals defines a single binary bit, and therefore a single character, on said recording means; and d. second recording means coupled to said generating means and associated with said recording medium for recording the binary bits of said input information within the appropriate binary intervals recorded on said medium by said first recording means.

5. A stenographic system as claimed in claim 4 wherein said machine includes a supporting means, and said keys move relative to said supporting means, said switches comprising a plurality of cantilevered wires, each rigidly supported at one end by said supporting means and mechanically coupled at another portion to said keys, whereby said wires are displaced when said keys are depressed, a common contact bar mounted on said supporting means at a position to contact said wires when they are displaced by depressing said keys, a source of electrical energy, and electrical circuit means for completing a circuit through said source of electrical energy, said switches and said storage means.