US3289806A - Control system for electric typewriters including current limiting means - Google Patents

Control system for electric typewriters including current limiting means Download PDF

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US3289806A
US3289806A US433609A US43360965A US3289806A US 3289806 A US3289806 A US 3289806A US 433609 A US433609 A US 433609A US 43360965 A US43360965 A US 43360965A US 3289806 A US3289806 A US 3289806A
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selecting
current
pulse
windings
electromagnetic
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Manus George
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J7/00—Type-selecting or type-actuating mechanisms
    • B41J7/02—Type-lever actuating mechanisms
    • B41J7/30—Preventing rebound or clash of levers or type members
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L13/00—Details of the apparatus or circuits covered by groups H04L15/00 or H04L17/00
    • H04L13/16—Details of the apparatus or circuits covered by groups H04L15/00 or H04L17/00 of transmitters, e.g. code-bars, code-discs

Definitions

  • the present invention has for its object a control system for the types of electric typewriters, data processing machines and the like wherein the types are controlled by a common electromagnetic striking mechanism and wherein each type is selected by means of an associated electromagnet energized by a key or switch, for example of the type described in my co-pending application Serial No. 277,424, led April 30, 1963.
  • the primary purpose of the present invention is to prevent such a blocking.
  • a control arrangement for a machine including type bars, whereby each type bar to be struck is selected by a selecting electromagnet associated with said type bar, while the striking operation is controlled by a mechanism which is common to all type bars and is actuated by at least one striking electromagnet, said arrangement including selecting means supplying as required an electric pulse controlling selectively the electromagnets associated with the type bars, the windings of said electromagnets being all connected with a common current limiting system the maximum intensity of the current passing through which is larger than that required for the operation of one selecting electromagnet without reaching a value double said required value, further means feeding a control pulse to the striking electromagnet when a predetermined period has elapsed after the selecting pulse.
  • FIG. 1 is a diagrammatic showing of a rst embodiment
  • FIG. 2 illustrates a second embodiment which is substantially simpler than the rst one.
  • FIG. 1 For the sake of simplicity, in the first embodiment of FIG. 1, only three operating key contacts of a plurality of operating contacts, such as on a keyboard, are shown for discharging their respective capacitors which, with their associate charging circuits, are designated 1, 2 and 3.
  • the charging circuits 1, 2 and 3 while shown in schematic block form, may each consist of a capacitor bridged by a resistance, such as shown in the comparable circuits in FIG. 2, at Ca, Ra; Cb, Rb; and Cc, Rc.
  • the discharge current ows through coil 4, 5 or 6 energizing the electromagnet which selects the type, the coils being joined to a common conductor which, via an impedance transformer 1li, well known in the art supplies a controlmodule to a coincidence or AND gate 9, well known in the art which results in the discharge current passing through a current limiter 16, such as an induction coil, which is adjusted to pass a discharge current which is suiiicient to energize only one coil.
  • a current limiter 16 such as an induction coil
  • the coincidence gate 9 is also supplied with continuous control pulses from a full-wave rectifier 7, of well known construction, fed from the mains, from which the ripple voltage having a frequency of cycles, is diierentiated in a differentiating circuit 8, well known in the art, to supply the required triggermodules.
  • the output signal from the coincidence gate 9 triggers a single pulse multivibrator 10, of standard known construction, which, via a delay circuit 11, of any of the well known types, controls an amplier 12 which supplies energy to the coil energizing the electromagnetic striking mechanism 13.
  • a control pulse is taken from the multivibrator 10 which is fed to a pulse lengthener 15 which lengthens the pulse from l0 ms. to 50 ms.
  • This pulse is fed to the coincidence gate 9 to block this for a required period of time in the event of two operating contacts being closed in too rapid succession.
  • the control pulse from the multivibrator 10 is also fed to the current limiter 16 to initiate the discharge through the energizing coil and to ensure that the discharge occurs only for the length of one pulse, i.e. 10 ms.
  • the method of operation is as follows:
  • the lengthened pulse is fed to the coincidence gate 9 and biocks this for 50 ms., in such a way that no new pulse from the units 7 and 8 can pass through until 50 ms. have elapsed since the operating pulse.
  • the control pulse from the multivibrator 10 is also fed to the current limiter 16 enabling the discharging of the capacitor through coil 4 to take place during the length of one pulse, that is to say l0 rns.
  • the coil 4 then energizes the appropriate electromagnet for selection of type.
  • the contro-l voltage across the input of the impedance transformer 1d will disappear, again blocking the coincidence gate 9, even after the cessation of the lengthened pulse from unit 15.
  • a new key may be depressed before the previous one is released without the first key initiating action afresh.
  • the capacitor is not recharged until the operating contact is released to the rest position.
  • the single pulse multivibrator 10 supplies, through the delay circuit 11, a control pulse to the amplifier which in turn supplies suilicient energy to operate the striking mechanism.
  • the delay circuit 11 delays the control pulse to the energizing coil about 2 ms. in relationship to the control pulse from the impedance transformer 1li, enabling the selected type to move into its initial position before the striking mechanism is energized.
  • the strength of the strike can be adjusted by adjusting the length of the control pulse with the help of a potentiometer (not shown) in the multivibrator 1l).
  • the selected energized coil receives current from the capacitors charging circuit.
  • the repetition frequency will thus be equal to the length of the blocking pulse from the pulse lengthener 15.
  • the duration can be varied by means of a potentiometer (not shown) in the pulse lengthener 15. This potentiometer is connected to the circuit only in connection with repetition.
  • FIG. 2 illustrates the second embodiment wherein only three type selecting arrangements have been illustrated, similar to FIG. l, with each arrangement including a switch or key respectively a, b, c.
  • Each key is connected on the one hand with the input point A and on the other hand with a condenser Ca, Cb or Cc as the case may be, each condenser being shunted by a resistance Ra, Rb or Rc.
  • Each condenser is connected with the output point B through a winding Wa, Wb or Wc respectively forming part of the type bar selecting means.
  • Said point B is connected with the negative terminal of a supply of D C. through a current limiter 17, for example through an induction coil the inductance of which is much larger than that of any winding of the selecting means.
  • the positive terminal of the same supply is connected with the point A which is also grounded.
  • the voltage at the point B forms the input signal feeding a chain of electronic circuits including a monostable multivibrator 18 of known construction, the time constant of which is equal to 2 ms., and an adjustable time constant circuit 20 controlled by said multivibrator 18 and producing for each impulse of 18 a longer pulse of approximately l5 ms., an amplier 21 adapted to supply said pulse into a winding 22 energizing electromagnetic strike-controlling means. Said amplier 21 forms at the same time a signal adapted to return through conductor C towards the multivibrator 18 to lock the latter in its stable position and to render it non responsive to an input signal.
  • Said multivibrator 18 controls an electronic switch means 19 adapted to transiently provide a direct connection between the points A and B.
  • the inscription of a symbol is controlled by the closing of the vswitches a, b, c, for instance through manual actuation by the typist of the corresponding key on the keyboard of a typewriter or else by an automatic arrangement controlling the typewriter, chiefly in the case where the machine serves for recording the results of the operations executed by a calculating machine.
  • the point B Before the closing of a switch, the point B is subjected to the negative voltage of the supply since it is connected with the latter through the induction coil 17. At the moment at which one of said switches, say the switch b, is closed, the potential of the point A is suddenly applied to the point B since the condenser Cb was not charged.
  • Said positive pulse reaching the point B produces a rocking of the multivibrator 18 into its non-stable position and simultaneously a pulse is produced thereby which closes the switch 19 during the 2 ms. period during which said multivibrator remains in its non-stable position.
  • the voltage at the point B is necessarily equal to that at the point A, so that no current flows through the winding Wb controlling the selection of the selected type bar.
  • the current begins flowing through the winding 17 without rising beyond a very low intensity by reason of the comparatively large inductance of said winding 17.
  • the multivibrator 1S After a period of 2 ms. reckoned from the closing of the switch b, the multivibrator 1S returns into its original stable position which opens again the switch 19 and sends a negative pulse into the input of the adjustable time constant circuit 2i). The latter produces a pulse of about l5 ms. which pulse is fed into the amplier 21.
  • the duration of the output pulse of the circuit Ztl is adjusted so as to modify the energy of said pulse after amplification in the amplifier 21 and consequently the striking force obtained by the passage of said pulse through the winding 22 may be modiiied as desired.
  • the condenser Cb can be charged by the supply of current and the charging current passes through the winding Wb with an intensity which is sufficient for producing the desired electromagnetic selection of the type bar associated with said winding.
  • the striking pulse supplied by the circuit Ztl and the amplifier 21 begins together with the current charging the condenser Cb, but due to the inertia of the striking mechanism, actual striking occurs only after the selection of the typing bar is completed.
  • the switch b When the switch b opens, for instance when the keyboard key is released by the typist, the condenser Cb is discharged speedily through the resistance Rb shunting it.
  • the circuit illustrated cuts out any risk of locking the machine by the striking of two keyboard keys simultaneously or in a too speedy sequence.
  • the operation is started as disclosed without any modification, that is the multivibrator 18 operates and the switch 19 is closed during 2 ms.
  • the charging current is limited by the induction coil 17 which allows the passage only of a current larger than that necessary for producing the operation of one selecting electromagnet, which is yhowever lower than twice the minimum selecting control current; therefore, the current passing through the winding 17 is subdivided into two elementary currents passing through the windings Wa and Wb, each of these elementary currents being insufficient for the selection of the corresponding type bar.
  • the multivibrator 18 is locked by the control signal or conductor C in its stable position. If a second switch is closed the selection controlled by said second switch can be obtained only if the switch is held closed after the end of the pulse controlling the striking in the winding 22.
  • the switch 19 produces a further useful safety in the case where the selection of a type bar is controlled through a catch carried by said type bar and attracted magnetically by one of the windings Wa, Wb In such a case, it may in fact occur that at the end of the striking operation the type bar returns into its inoperative position and the catch is subjected to a rebound movement which causes it to engage the cooperating maget even if the feeding current is much weaker than that required for control purposes.
  • a switch for instance a, remains closed after the striking operative current continues flowing through the corresponding winding Wa by reason of the presence of the resistance Ra, this current having an intensity ranging between the third and one half the peak selecting current.
  • Said current is sufficient for holding in its attracted position a catch which may have rebounded back against the electromagnet armature.
  • the discharging current of Ca passes through the winding Wa in a direction opposed to that of the residual current, in a manner such that the current is practically wiped out and the electromagnetic action of said winding is cut out. If a selecting catch has engaged the magnetized bar carrying the winding Wa as a consequence of its rebound, the wiping out of the current in said winding ensures automatically the return of said catch into its inoperative position.
  • the circuit described can serve readily for the repeated striking of a same symbol by cutting off the connection between the terminals of the switches a, b, c with the point A and by connecting all said terminals with the line C receiving the pulses supplied by the amplifier 21.
  • the multivibrator 18 should be transformed into an astable multivibrator through mere switching.
  • the switches a, b, c will no longer be subjected to a voltage which is continuously equal to zero, but are connected with a point at an alternatingly negative and zero voltage.
  • the selecting current passes through the winding associated with the closed switch.
  • a control arrangement comprising selecting electromagnetic windings adapted to select the corresponding type bars, a common current-limiting device, charge storage circuits, a plurality of different parallel circuits, each of which comprises a said charge storage circuit and a said selecting winding in series, connected for insertion in series with said common currentlimiting device, said device being adapted to limit the current passing through it to a value ranging between values above once and below twice that required for one of the said electromagnetic windings to be operative, electromagnetic means connected for controlling the striking mechanism, individual operating means connected in series with each charge storage circuit and selecting winding to energize selectively the said selecting electromagnetic windings with the current in the respective charge storage circuits to produce an energizing pulse in the latter and circuit means connected to said selecting windings and said current-limiting device to energize the electromagnetic means controlling the striking mechanism whereby upon consecutive operation of a first and second operating means without release of the rst operating
  • a control arrangement comprising selecting electromagnetic windings adapted to select the corresponding type bars, a condenser inserted in series with each selecting electromagnetic winding, a resistance inserted across each condenser, a common current-limiting device, a plurality of different parallel circuits, each of said parallel circuits constituted by a said winding, condenser and resistance, connected for insertion in series with said common current-limiting device, said device being adapted to limit the current passing through it to a value ranging between values above once and below twice that required for one of the windings to be operative, electromagnetic means controlling the striking mechanism, operating means connected in series with each of said parallel circuits to energize selectively the selecting electromagnetic windings to produce an energizing pulse in the latter with the current in the respective condenser, and delaying means fed by each pulse and adapted t0 energize the electromagnetic means controlling the striking mechanism at a predetermined moment following
  • a control arrangement comprising selecting electromagnetic windings adapted to select the corresponding type bars, a condenser inserted in series with each selecting electromagnetic winding, a resistance inserted across each condenser, a common current-limiting device with which different parallel circuits, each constituted by a winding, condenser and resistance, are inserted in series, said device being adapted to limit the current passing through it to a value ranging between values above once and below twice that required for one of the said electromagnetic windings to he operative, electromagnetic means controlling the striking mechanism, operating means connected in series with each parallel circuit to energize selectively the selecting electromagnetic windings to produce an energizing pulse in the latter with the current stored in the respective condenser, and a delay circuit subjected to the pulses upon operation of the operating means and adapted to feed a pulse controlling the operation of the electromagnetic means controlling the striking mechanism at a predetermined moment following the production of
  • a control arrangement comprising selecting electromagnetic windings adapted to select the corresponding type bars, a common current limiting device with which the different parallel windings are inserted in series, said device being adapted to limit the current passing through it to a value ranging between values above once and below twice that required for one of the windings to be operative, electromagnetic means controlling the striking mechanism, operating means energizing selectively the selecting electromagnetic windings to produce an energizing pulse in the latter, a coincidence gate fed with the pulses passing out of the windings, means continuously feeding periodical pulses to said coincidence gate to produce in association with the pulses from the energizing windings output signals, a circuit controlled by said signals and connected to said current-limiting device, adapted to energize the electromagnetic means controlling the striking mechanism and a feed-back circuit between said circuit and the coincidence gate and adapted upon reception of the signal to block the latter against operation during a predetermined
  • a control arrangement comprising selecting electromagnetic windings adapted to select the corresponding type bars, a common current-limiting device with which the different selecting windings are inserted in series, said device being adapted to limit the current passing through it to a value ranging between values above once and below twice that required for one of the windings to be operative, electromagnetic means controlling the striking mechanism, operating means energizing selectively the selecting electromagnetic windings to produce an energizing pulse in the latter, a coincidence gate fed in parallel With the current-limiting device, means continuously feeding periodical pulses to said coincidence gate to produce in association with the pulse from the energizing winding an output signal, a single pulse multivibrator controlled by said signal, means for adjusting the duration of the pulse produced by the multivibrator and means whereby the pulse fed by the multivibrator energizes the electromagnetic means controlling the striking mechanism and a feed-back circuit inserted
  • a control arrangement comprising selecting electromagnetic windings adapted to select the corresponding type bars, a common current-limiting device with which the different parallel connected selecting windings are inserted in series, said device being adapted to limit the current passing through it to a value ranging between values above once and below twice that required for one of the windings to be operative, electromagnetic means controlling the striking mechanism, operating means energizing selectively the selecting electromagnetic windings to produce an energizing pulse in the latter, a coincidence gate fed in parallel with the current-limiting device, means continuously feeding periodical pulses to said coincidence gate to produce in association with the pulse from the energizing winding an output signal, a single pulse multivibrator controlled by said signal, said multivibrator producing an output pulse of adjustable duration, an amplifier feeding said output pulse to the electromagnetic means controlling the striking mechanism to energize the latter, and a feed-back circuit between the multivibrator and
  • a control arrangement comprising selecting electromagnetic windings adapted to select the corresponding type bars, a common current limiting device with which the different parallel windings are inserted in series, said device being adapted to limit the current passing through it to a value ranging between values above once and below twice that required for one of the windings to be operative, electromagnetic means controlling the striking mechanism, operating means energizing selectively the selecting electromagnetic windings to produce an energizing pulse in the latter, a coincidence gate fed in parallel with the current limiting device, means continuously feeding periodical pulses to said coincidence gate to produce in association with the pulse from the energizing winding an output signal, a single pulse multivibrator controlled by said signal, a delay circuit adapted to delay the pulse fed by said' multivibrator, an amplifier feeding the delayed pulse to the electromagnetic means controlling the striking mechanism to energize the latter, and a pulse lengthening feed-back circuit
  • a control arrangement comprising selecting electromagnetic windings adapted to select the corresponding type bars, a condenser inserted in series with each selecting electromagnetic winding, a resistance inserted across each condenser, a common current-limiting system inserted in series with the parallel circuits constituted by the different windings and associated condensers and resistances, a supply of electrical energy feeding said common current-limiting system and parallel circuits, a switch controlling each parallel circuit, a monostable multivibrator, an adjustable time constant circuit fed by said multivibrator, said multivibrator being connected to said current-limiting system and to the output of said selecting windings, electromagnetic means through which the signals produced with a predetermined delay by said time constant circuit upon energization of any parallel circuit operate the striking mechanism whereby upon consecutive operation of a rst and second switch in different parallel circuits without release of the rst switch corresponding selecting winding
  • a control arrangement comprising selecting electromagnetic windings adapted to select the corresponding type bars, a condenser inserted in series with each selecting electromagnetic winding, a resistance inserted across each condenser, a common current, limiting induction coil inserted in series with the parallel cir- CIltS CQDSitLlted by the, different windings and associated condensers and resistances, a supply of electrical energy feeding said induction coil and parallel circuits, a switch controlling each parallel circuit, a monostable multivibrator in parallel with the induction coil, a time constant circuit fed by the multivibrator, electromagnetic means through which the signals produced with a predetermined delay by the time constant circuit upon energization of any parallel circuit operate the striking mechanism, a switch means controlled by the multivibrator and adapted to short-circuit transiently the parallel circuits upon energization of said multivibra

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Electronic Switches (AREA)
  • Accessory Devices And Overall Control Thereof (AREA)
  • Keying Circuit Devices (AREA)
  • Magnetic Treatment Devices (AREA)
US433609A 1964-02-29 1965-02-18 Control system for electric typewriters including current limiting means Expired - Lifetime US3289806A (en)

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CH (1) CH410998A (fr)
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GB (1) GB1077522A (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3436735A (en) * 1966-09-01 1969-04-01 Sperry Rand Corp Keyboard operated repeat circuit for a data processing system's operator control unit
US3528535A (en) * 1967-03-07 1970-09-15 Siemens Ag Locking means for keyboard transmitting successive control commands
DE1761054B1 (de) * 1968-03-28 1971-12-23 Kienzle Apparate Gmbh Elektrische steuereinrichtung zum veraendern des zeitlichen abstandes aufeinanderfolgender typenhebelanschlaege
US3679036A (en) * 1969-08-14 1972-07-25 Paul F Gloess Key board printer

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US920940A (en) * 1907-06-04 1909-05-11 Henry M Ferry Machine for combining an adding-machine and type-writer.
US1374152A (en) * 1909-11-29 1921-04-05 Telegraph transmitter
US1455112A (en) * 1922-07-25 1923-05-15 Addograph Co Typewriting machine
US1678492A (en) * 1926-12-02 1928-07-24 John W Lambert Electromagnetic attachment for key-controlled mechanisms
US1753991A (en) * 1927-04-18 1930-04-08 Leonard W Langford Keyboard operator
US2869703A (en) * 1953-06-08 1959-01-20 Grundig Max Type key blocking mechanism
US2891649A (en) * 1957-05-13 1959-06-23 Royal Mcbee Corp Manual and/or electric typewriters
US2942253A (en) * 1956-11-19 1960-06-21 Hupp Corp Switching system control
US3017978A (en) * 1960-12-15 1962-01-23 Royal Mcbee Corp Fault sensing apparatus
US3091320A (en) * 1961-04-10 1963-05-28 Olympia Werke Ag Control circuit arrangement for electric typewriter
US3151722A (en) * 1962-09-28 1964-10-06 Olivetti & Co Spa Spring actuated typewriter action with fault sensing means

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US920940A (en) * 1907-06-04 1909-05-11 Henry M Ferry Machine for combining an adding-machine and type-writer.
US1374152A (en) * 1909-11-29 1921-04-05 Telegraph transmitter
US1455112A (en) * 1922-07-25 1923-05-15 Addograph Co Typewriting machine
US1678492A (en) * 1926-12-02 1928-07-24 John W Lambert Electromagnetic attachment for key-controlled mechanisms
US1753991A (en) * 1927-04-18 1930-04-08 Leonard W Langford Keyboard operator
US2869703A (en) * 1953-06-08 1959-01-20 Grundig Max Type key blocking mechanism
US2942253A (en) * 1956-11-19 1960-06-21 Hupp Corp Switching system control
US2891649A (en) * 1957-05-13 1959-06-23 Royal Mcbee Corp Manual and/or electric typewriters
US3017978A (en) * 1960-12-15 1962-01-23 Royal Mcbee Corp Fault sensing apparatus
US3091320A (en) * 1961-04-10 1963-05-28 Olympia Werke Ag Control circuit arrangement for electric typewriter
US3151722A (en) * 1962-09-28 1964-10-06 Olivetti & Co Spa Spring actuated typewriter action with fault sensing means

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3436735A (en) * 1966-09-01 1969-04-01 Sperry Rand Corp Keyboard operated repeat circuit for a data processing system's operator control unit
US3528535A (en) * 1967-03-07 1970-09-15 Siemens Ag Locking means for keyboard transmitting successive control commands
DE1761054B1 (de) * 1968-03-28 1971-12-23 Kienzle Apparate Gmbh Elektrische steuereinrichtung zum veraendern des zeitlichen abstandes aufeinanderfolgender typenhebelanschlaege
US3679036A (en) * 1969-08-14 1972-07-25 Paul F Gloess Key board printer

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CH410998A (fr) 1966-04-15
DE1436681B2 (de) 1971-03-04
GB1077522A (en) 1967-08-02
DE1436681A1 (de) 1969-03-13

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