US2512860A - Control means for electric typewriters - Google Patents

Description

June 27, 1950 w. H. HENRICH 2,512,860

' CONTROL MEANS FOR ELECTRIC TYPEWRITERS Filed June 18, 1949 3 Sheets-Sheet 1 FIG. I

mm m l i l i'l l l l'l HUNDRED PROGRAM URCUIT ATTORNEY.

June 27, 1950 w. H. HENRICH 2,512,360

CONTROL MEANS FOR ELECTRIC TYPEWRITERS Filed June 18, 1949 3 Sheets-Sheet 2 FIG. 2 W

INVENTOR. WILLIAM H. HENRICH ATTORNEY.

Patented June 27, 1950 CONTROL MEANS FOR ELECTRIC TYPEWRITERS William H. Henrich, East Norwalk, Cnn., as-

signor to Remington Rand Inc., New York, N. Y., a corporation of Delaware Application June 18, 1949, Serial No. 100,016

Claims. (Cl. 23558) This invention relates to a. combination of an electronic control means and a typewriter which is provided with several sets of numeral type bars. It has particular reference to the combination of an electric typewriter and electronic input circuits which makes possible a speed of three or four times the present typing speed.

The maximum speed of present typewriters is limited by the time required for .a type bar to be actuated by an electrical mechanism, strike the platen, and return to its unactuated position. When difierent characters are being printed, there may be considerable overlapping in the mechanical operation since one type bar may be starting towards the platen while the previously operated type bar is returning, but in the case of repeated characters, the same type bar in present day arrangements must be fully returned before it can be actuated forthe second time. The typewriter used with the present invention is modified to the extent that three sets of numeral type bars are used, and the electronic control is so arranged that successive numbers are selected successively from different sets of type bars. This arrangement permits the typing of similar characters, such as a number of zeros, at the same speed as different characters may be typed, and it also provides greater overlapping of the mechanical operation because the three sets of type bars are separated at a greater mechanical angle and the tendency to pile up near the platen is largely eliminated.

One of the objects of the present invention is to provide an improved typing arrangement which eliminates many of the difficulties and limitations of prior art machines.

Another object of the invention is to increase the speed of numeral typing to three or four times the present speed.

Another object of the invention is to reduce the tendency of type bars to strike each other during the typing operation.

One feature of the invention includes a control means for an electric typewriter which comprises a plurality of sets of numeral type bars, generally three. Each bar is operated by a solenoid which is energized by one of ten gaseous discharge devices. A switching circuit, generally called a Lewis ring, is employed to sequentially apply a control pulse to the sets of solenoids. A numeral designating circuit, generally run from a keyboard, selects the corresponding gaseous discharge device and provides it with an operating potential.

Another feature of the invention includes a timing circuit which operates the switching circuit each time a character is printed so that successive characters are always printed from different sets of type bars.

For a better understanding of the present invention, together with other and further objects thereof, reference is made to the following description taken in connection with the accompanying drawings.

Fig. 1 is a schematic diagram of connections of part of the control circuit showing an accumulator and program circuit indicated by blocks.

Fig. 2 is a, schematic diagram of connections of another part of the control circuit.

Fig. 3 is a schematic diagram of connections of the third part of the control circuit.

Fig. 4 is a series of graphs showing voltage values in various parts of the circuit plotted against time.

' Fig. 5 is a diagram to indicate how the complete circuit may be obtained from Figs. 1, 2, and 3.

Referring now to Figs. 1, 2, and 3, a three order accumulator comprising a units counter l2, a tens counter I I, and a hundreds counter i 9, is indicated at the bottom of Fig. 1. A shifting circuit I3 is employed to shift the stored values from one counter unit to another so that a number in the hundreds counter may first be printed, then the entire set of values shifted, putting the value of the tens counter into the hundreds counter, and the value of the units counter into the tens counter. Then the tens digit is printed and another shift operation shifts the units value to the hundreds counter where it may be sent to the printing circuit. A shifting circuit capable of performing the above operation has been described in a patent application, S. N. 91,060, filed May 3, 1949.

The digit values are transmitted to the printing circuit by a series of seven conductors I4 which carry the information in a code to save wires and electron tubes. The biquinary system of notation is used which is a combination of a radix-of-five system and a radix-of-two system. However, the circuit can be easily altered to work with any of the usual systems of notation.

The conductors M are connected to the control electrodes of ten gas filled electron discharge devices I5 to 24. These tubes are normally in the non-conducting condition and pass no current because the control electrodes are all biased with a potential below the cut-off value. Connected to each anode of the tubes IE to 24 are three solenoids comprising a group, each soleto U. S. Patent No. 2,172,749, issued September 12, 1939, to G. G. Going, and No. 2,288,846, issued July 7, 1942, to F. W. Schremp.

The circuit which controls the typing speed is derived directly from the 60 cycle alternating current supply. This supply is connected to a transformer 25 (Fig. 2) and the transformer output is applied to a trigger stage 26 by means of conductor 21. The stage is actuated every half cycle, conducting first on one side, then on the other. The output of stage 26 is transferred by conductor 28 to stage 30, which is also a trigger stage, the circuit constants being so chosen as to cause actuation Only when negative pulses are received.

A graph in Fig. 4 shows how the voltage pulses are generated. At 4--l the sine wave of the input voltage is shown. In graph 4-2 the output of stage 26 is shown. An output conductor 31, similar to conductor 28, applies the output of stage 35 to an electronic gate stage 32. The

pulses which are transmitted over conductor 3| are shown in graph 43 and have a frequency of 30 cycles or half of'the power frequency.

The electronic gate stage 32 delivers no out put unless a typing start signal has been sent from the program circuit 36'. If a start signal is applied by way of conductor 12 to trigger stage 34, the trigger stage is actuated and conduction is shifted to the right hand side. Normal or quiescent conduction is on the left hand side as indicated by the cross-hatched lines. When the left hand anode is non-conducting, its potential increases and a conductor 35 applies this higher potential to the left hand control electrode of gate stage 32, thereby permitting the 30 cycle pulses from stage 30 to pass through the gate and be amplified by it. The output of the left hand triode is applied to the right hand triode by means of conductor 3! and the output of this triode, a positive pulse (44), is applied to a ring trigger circuit by means of conductor 88. The ring trigger circuit includes the left hand triodes of stages 40, 4|, and 42, and is interconnected in such a manner that two of the left hand triodes are always conductingwhile the third is not. Such a circuit is sometimes called a Lewis ring, and has been described in Electrical Counting by W. B. Lewis, pages 90 and 91, published in 1943 by the Macmillan Co.

Successive positive pulses applied over conductor 38 to all the left hand control electrodes cause the ring to step around. For example, let it be assumed that the left hand triode of stage-40 is non-conducting while the left hand triodes of stages 4| and 42 are conducting. This is a stable condition because the anode current through resistor 43 reduces the potential on conductor 44 and the anode current through resistor 45 reduces the potential on conductor 46. The control electrode of triode 40 is connected to both these conductors andis, therefore, biased below the cut-01f value. The control electrodes of triodes ll and 42 are each connected to a low potential conductor and a high potential conductor 41, the resulting potential permitting current to flow in the anode circuit.

If now a positive pulse is applied to all three left hand control electrodes, triodes All and 52 will not be primarily aifected since they are already in the conducting condition. The left hand Side of stage 40 is made conducting and, as current starts flowing through the anode circuit, a negative pulse is sent through capacitor 48 to the control electrode of triode 4i, reducing its potential and cutting off the anode current.

In the above described manner the non-conducting condition has been transferred from triode 40 to triode 4|. A second positive pulse over line 38 will advance the non-conducting condition to triode 42 and a third, back to triode 40, the original condition.

Each time a ring triode starts conducting, a negative pulse is sent to the right hand triode in the same envelope. The pulse is amplified and sent out over one of the coupling conductors 50, 5|, or 52 as a positive pulse.

These pulses are shown graphically in Fig. 4 (45, 46, and 4-1). The pulses are applied to the control electrodes of three gas filled power amplifier tubes 53, 54, and 55, the anode supply of which is connected directly to the 220 volt, sixty cycle power line. The power amplifier tube output circuits are cathode-follower connected and include resistors 56, 5?, and 58. The output pulses are delivered over lines 65, BI, and 62 to the solenoid sets which include ten solenoids, each for operating a key lever from 0 to 9, inelusive.

Power amplifier stages 53, 54, and 55 are operated by sharp pulses shown graphically in Fig; 4. The tubes, being gas filled, continue to conduct for the remainder of the sixty cycle positive wave and deliver a pulse of longer duration, thereby transmitting considerably more energy to the solenoid which controls the typing mechamsm.

When the power pulses are delivered to the solenoids, voltage is supplied to one of three control circuits which comprise neon lamps 63, 64, and 55, and balast resistors 65, 61, and 58. The three circuits are connected to the right hand control electrode of a Schmit trigger stage ill which is actuated each time a pulse is sent to the solenoids, the actuation continuing for as long as the duration of the pulse voltage. During the change in conductance a positive pulse is generated at the left hand anode which is transmitted over conductor H to the shift circuit l3, to cause all digits'stored in the counters 10, H, and [2 to shift to the next higher counter unit. The shifting operation is arranged to occur when the pulse ends so that enough time will be available for the printing operation. The impulse sent over conductor ll is shown graphically in Fig. 4 (4l l) To stop the printing operation, a stop signal is run from the program circuit 36, over conductor 33, to trigger stage 34 to transfer conductance back to the left hand anode. This lowers the potential on conductor 35 and the control electrode of gate stage 32, thereby cutting off the thirty cycle impulses from stage 30 and stopping the printing action.

In order to disclose the operation of the circuit in greater detail, let it be assumed that the number 941 has been entered into the accumulator units If], H, and I2. Let it also be assumed that the transformer has been connected to a 60 cycle power line and, therefore, a 30 cycle alternating potential is being applied on conductor 3| but causes no action since gate 32 is closed. The left hand triode of stage 40 in the Lewis ring is non-conducting, the other two are conducting as is indicated by the cross-hatched lines in the figure.

If a start pulse is now sent out from the program unit 36, over conductor 42, to trigger stage 34, the conductance of that stage will be transferred to the right hand anode and a positive potential applied to the left hand control electrode of stage 32, opening the gate, and thirty cycle pulses will be transmitted over conductor 38 to the Lewis ring 40, 4!, and 42.

The first thirty cycle pulse actuates the ring circuit, transferring the non-conducting condition from triode 40 to triode 4i A positive pulse is sent over conductor 50 to power amplifier 53 which in turn sends an amplified positive pulse (which continues for about /150 second) over conductor 60 to all the solenoids 80A to 89A, inelusive.

The 9 registered in the hundreds counter causes an increase in voltage to be applied to conductors SI and 98 (bi-quinary code). These two conductors are connected to the two control electrodes of the gas filled tube 24 which is characterized by the fact that conduction is possible only when both control electrodes have been raised in potential. As a result, solenoid 89A passes current, the type bar in the A set is actuated, and a 9 is printed. After conduction has been started in tube 24 it continues until the anode potential is removed.

Concurrently with the actuation of solenoid 89A, neon light 65 is lighted and an actuating voltage impressed on the right hand control electrode of trigger stage 10, a modified form of Schmit trigger, and an impulse (4! l) is sent to the shift circuit 3 to shift all digits in the counters l0, I, and I2. The shift circuit is described in copending application, Serial No. 91,060, filed May 3, 1949, by L. P. Crosman. This circuit contains a multivibrator which is started by the trailing edge of the signal pulse over conductor it and the output of the multivibrator, when amplified, causes the 9 to be shifted to the units counter; the 4 is shifted from the tens counter to the hundreds counter and the 1 is shifted from the units to the tens counter. The multivibrator action introduces enough delay so that the shift is made after the gas filled tube 24 has been put out of the conducting condition.

After the above described electrical pulse action (at time 151) nothing happens to the electrical circuits of Figs. 2 and 3 for about of a second. During this time the type bar completes its printing action and starts to return to its unactuated position. At time t2 (Fig. 4) another pulse is sent over conductor 38 to the Lewis ring circuit (stages 40, 4|, and 42) and the nonconducting condition is transferred from stage M to stage 42. A positive pulse is sent over conductor 5! to power amplifier 54 which sends a positive pulse over conductor 61 to all the solenoids 80B to 8913, inclusive.

The hundreds counter it! now contains the digit 4 which causes positive voltages to be applied to conductors 90 and 94, giving a positive bias to both control electrodes in tube l9 and causing the tube to conduct. Current flows through solenoid 84B and causes the 4 type bar in the second set to be actuated and print. When the pulse is sentover conductor 6!, neon light 64 is lighted which causes stage 10- to trigger and cause the shift action as previously described.

At time t; a 1 will be registered in the hundreds order counter I0 and the third thirty cycle pulse will shift the non-conducting condition in the Lewis ring from stage 42 to stage All, thereby sending a positive pulse over conductor 52 to power amplifier 55, lighting neon lamp B3 and energizing solenoids C to 89C, inclusive. The 1 in the hundreds counter causes positive voltages to be applied to conductors 9i and QIA which combine to cause conduction in tube !6 and permit current to flow in solenoid SIC. The 1 type bar in the third set is actuated and prints the figure 1. Stage H3 is actuated as before to cause a shift of digits in the counter system.

The program circuit now sends a stop signal over conductor 33 to the right hand control electrode of trigger stage 34 which shifts its conductance back to the left hand anode, the normal condition. This lowers the bias on the left hand control electrode of gate stage 32 and blocks the thirty cycle impulses from stage 30 to keep them from actuating the Lewis ring.

While the above example did not include repeated figures, it will be obvious that another 1 will be printed by solenoid BIA from the first set of type bars and the mechanical action will in no way conflict with the previously printed 1 due to solenoid 8 IC.

While there have been described and illustrated specific embodiments of the invention, it will be obvious that various changes and modifications may be made therein without departing from the field of the invention which should be limited only by the scope of the appended claims.

What is claimed is:

1. A control means for an electric typewriter comprising; a typewriter having a plurality of sets of numeral keys, each key being controlled by a solenoid; a plurality of electron discharge devices, one for each numeral, for supplying elec-- tric power to the solenoids; a switching circuit for sequentially applying a timed control pulse to the sets of solenoids; and a numeral-designating circuit for supplying an operating potential to one of said electron discharge devices.

2. A control means for an electric typewriter comprising; a typewriter having a plurality of sets of numeral keys, each set comprising keys from 0 to 9 and each key being controlled by a solenoid; ten electron discharge devices, each for supplying electric power to a group of solenoids; a switching circuit for sequentially applying a timed control pulse to the sets of solenoids; and a numeral-designating circuit for supplying an operating potential to one of said electron discharge devices.

3. A control means for an electric typewriter comprising; a typewriter having a plurality of sets of numeral keys, each set comprising keys from 0 to 9 and each key being controlled by a solenoid; ten electron discharge devices, each for supplying electric power to a group of solenoids; a switching circuit comprising a plurality of ring-connected trigger stages for sequentially applying a control pulse to the sets of solenoids; and a numeral-designating circuit for supplying an operating potential to one of said electron discharge devices.

4. A control means for an electric typewriter comprising; a typewriter having a plurality of sets of numeral keys, each set comprising keys from 0 to 9 and each key being controlled by a solenoid; ten electron discharge devices, each for supplying electric power to a group of solenoids; a switching circuit comprising a plurality of ringconnected trigger stages and associated gate stage for sequentially applying a control pulse to the sets of solenoids; and a numeral-designating circuit for supplying an operating potential to one of said electron discharge devices.

5. A control means for an electric typewriter comprising; a typewriter having a plurality of sets of numeral keys, each set comprising keys from 0 to 9 and each key bein controlled by a 8 solenoid; ten electron discharge devices, each for supplying electric power to a group of solenoids; a switching circuit comprising a plurality of ringconnected trigger stages and associated gate 5 stages for sequentially applying a control pulse to the sets of solenoids; a number-designating circuit for supplying an operating potential to one of said electron discharge devices; and an actuating circuit for operating the switching cir- 10 cuit each time a character is printed.

WILLIAM H. HENRICH.

No references cited.

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