US2096145A

US2096145A - Teletypewriter

Info

Publication number: US2096145A
Application number: US82639A
Authority: US
Inventors: Swezey Burdette Stevens
Original assignee: American Telephone and Telegraph Co Inc
Current assignee: AT&T Corp
Priority date: 1936-05-29
Filing date: 1936-05-29
Publication date: 1937-10-19
Anticipated expiration: 1954-10-19

Description

oct. 19, 1937. B s, sw Y 2,096,145

TELETYPEWRITER Filed May 29, 1936 INVENTOR By B.$.SWEZ'V ATTORNEY Patented Oct. 19, 1937 TELETYPEWRITEB Burdette Stevens Swezey, Floral Park, N. Y., as-

signor to American Telephone & Telegraph Company, a corporation of New York Application May 29, 1936, Serial No. 82,639

11 Claims.

This invention relates to a motor control device for teletypewriters and, more particularly, to a device for stopping the motor of an unattended teletypewriter which may, if desired, be located at a remote station.

Heretofore, an operator at a control station has stopped the motor of an unattended teletypewriter, such as a teletypewriter located at a remote station, by transmitting to the unattended teletypewriter a motor stop signal composed of a preassigned combination of significant current variations, such as those corresponding to an upper case H signal. A system of this type is shown in Patent 1,566,295 granted December 22, 1925 to E. F. Watson. The disclosure of this Watson patent is incorporated herein by reference as a part of this specification. However, it has been found that, under certain conditions, motors of unattended teletypewriters have been unintentionally stopped by various causes, such as the operator at the control station accidentally striking the stop key or because of disturbances in the line simulating an upper case H signal.

Accordingly, this invention has for its object the reduction of such unintentional stopping of remote motors. This is accomplished by installing a mechanical latch and associated parts in the teletypewriter to be controlled. This latch prevents the motor stop lever from operating in response to the usual motor stop signals. The latch is designed to be released, or unlatched, by a lever which is operated in response to the reception of a preassigned teletypewriter signal, such as a blank signal. The release of the latch allows the operation of the motor stop function lever to be effective to stop the teletypewriter motor. .Thus, the motor of the controlled unattended teletypewriter will be stopped in response to the reception by that teletypewriter of a blank signal immediately followed by an upper case H signal. The latch is restored to its normal, or operated, position by the operation of the universal function lever which operates, after the teletypewriter has been started by a motor start signal, in response to the reception by that teletypewriter of any teletypewriter signal for causing typing or spacing.

The invention will now be explained in detail with reference to the drawing in which:

Figure 1 indicates schematically a simple teletypewriter system to which the invention may be applied;

Fig. 2 illustrates the preferred embodiment of the invention in its normal, or unoperated, condition;

Fig. 3 shows this embodiment in its operated position;

Fig. 4 represents a modified form of the invention in its normal, or unoperated, condition;

and i Fig. 5 shows this modification in its operated condition.

For purposes of explanation, the invention is to be understood as being applied to a teletypewriter of the type disclosed in Patent 1,904,164 granted April 18, 1933 to S. Morten et al., although the invention is not restricted to this kind of teletypewriter. The disclosure of this Morton et al. patent is incorporated herein byreference as a part of this specification. The drawing shows only those parts of the teletypewriter that are necessary to illustrate the manner in which the invention is applied to the teletypewriter shown in the Morton et al. patent. Accordingly, the apparatus shown in the drawing corresponds to that shown in Figs. 27, 28, etc. of the Morton et al. patent.

In the simple teletypewriter system, shown in Fig. 1, if an operator at a. control station A, which may be a central oflice if desired, wishes to transmit a message to the unattended station B, she first connects the telegraph line L to her teletypewriter T by any convenient means, such as switch S. The motor M at the unattended station B may be started by the operator at station A by any of the methods well known in the art, such as the method described in the Morton et al. patent, supra. The operator then transmits the desired message to station B. After the message has been transmitted to station B, the operator at station A may wish to stop motor M at station 13 in which case she first transmits a preassigned signal over line L to station B. This preassigned signal may be any desired signal, such as a socalled blank signal in which all the current impulses composing the code signal are spacing impulses.

Just before this blank signal is received, the motor control apparatus at station B is in its normal, or unoperated, condition as is shown in Fig. 2 which is somewhat similar to Fig. 27 of the Morton et al. patent, supra, except for a few added parts. One of the parts addedis a. bent lever ll having'one end secured to the pivot 482 o! lever 483 and the other end attached to the end 415 of arm 41.4 of T-lever 4 by the adiusting screw "6. Another added part is a hairpin member l4 clamped between the bent lever II and a plate l3 by bolts l2-l2. Still another added art is a blocking lever l5 pivotally attached to the anchor plate 8 by a fixedly located pivot I6.

This blocking lever I5 has one'end I1 positioned between the prongs of member I4 and has its other end I 8, which is notched, normally in engagement with the motor stop function lever 48L.

Thus, under normal conditions, the motor stop function lever 48I can not be operated because, as can be seen in Fig. 2, its travel forward'is 'blocked by its engagement with the notched end I8 of lever I5. Since lever I5 is heldin place by pivot I6, which is fixedly located, leverli can not be pushed forward to allow function lever 4lI to rotate forward.

When the blank signal is received, the selecting mechanism of the teletypewriter T1 at station B operates to actuate the "blank function lever 463 which accordingly moves its extension 465 downward. This'causes arm 4 of T-lever 461 to also move downward thereby rotating T- lever 461 about its pivot 458 to its operated position where it is held by'means of the spring washer 412. The rotation of T-lever 461 causes its vertical arm "I, which is pivotally connected to arm 413 of T-lever 444 by pivot496, to force T-lever 444 to the left.

When T-lever 444 moves to the left, it carries with it the lever II, plate I3 and'the hairpin member I4. Themovem'ent of member I4 to the left, shifts the end I1 of the blocking lever I! to the left thereby swinging the notched end II of lever I5 to the right out of engagement with function lever 4M which is thus conditioned for operation as is shown inFig. 3. y

The operator at station A now transmits a socalled shift" signal. In'response to the reception of this shift signal, the sixth vane 50 of the teletypewriter T1 will move to tilt its front end downward as is described in the Morton et a1. patent. The sixth vane 50 is thus placed in the proper position to allow the motor stop function lever "I to be selected andto move forward to perform its functions.

The operator next transmits the third signal which may be another shift signal as' described in the Morton et al. patent, or, more preferably,

a preassigned signal such as I-I" as is described in the Watson patent, supra. The selecting mechanism in the teletypewriter T1 responds. to this code signal and effects the selection .of the motor stop function lever 48I which operates and rotates clockwise on its pivot I18 thereby moving its arm 506 downward until the extension 534 contacts with the adjusting screw. 419.

As is described in the Morton et al. patent, supra, the rotation of the motor stop function lever 48I moves its other arm 505 upward thereby causing the arm 509 of the motor stop lever 502 to strike against the end "I of the, contact operating lever499 which, consequently, rotates clockwise on its pivot I16. In rotating, lever4l9 moves its other end 503 downward to allow'contact 491 to open thereby effecting theopening of the energizing circuit of motor M with the consequent stopping of motor M. Itshould be noted that contact 498 will be closed for-a brief interval by arm 506 to allow the printing cycle to be completed for the purpose described in the Morton et al. patent, supra, or for performing any other function that may be'desired.

- The energizing circuit of the motor M will now remain open until the operator at station A transmits a start signal to close contact 481 and start motor M, such as-in the manner described in the Morton et al. patent, supra. Then, upon the receipt of any code signal which causes printing or spacing, the universal function lever 490 will operate and move its arm 4 downward thereby forcing downward arm 4" of T-lever 461 and V shifting the vertical arm 4 to the right. This pulls T-lever 444 and the bent lever II to the right. As a result, member I4 is moved to the a right thereby shifting end I1 of lever It to the right and moving the notched end II to left and into engagement with function lever I thus restoring the motor stop apparatus to its'normal condition as shown in Fig. 2.

Thus, it can be seen, that by means of this motor stop device, the remotely controlled teletypewriter motor can be stopped only in response to combinations of three signals: namely, "blank, shift", and "H" or shift, blank", and H". If desired, the device could bedesigned, by modifying the arrangementof the selecting vanes and their associated apparatus, to operate with the motor stop signal describedin the Morton et a1. patent and would then be fblank, "shift", and shift or shift", fblankffi'and "shift". It is to be understood that any other suitable character, such as M", may. be used instead of "H", if desired. In this connection it'should be noted that, since the universal function lever 400 opcrates only in respons'e toany signal which causes printing or spacing, function combinations, may be interposed in the abovesequences and will have no detrimental effect on the operation ofwthe signal is-.transmitted,1the apparatus is notin the.

condition to respond'en'ectively to the upper case Hflsignal because, should the motor stop function lever I then attempt to enter the selector vanes of the teietypewriter, it would find its forward movement 1 blocked by lever Ii. These motor stop contacts may be employed in a variety of circuits, such as. in place of the stop bar contacts I3 shown in Fig. l. in Patent 2,031,934 granted February 25, i936 to T. L. Corwin. The disclosure of this vCorwin patent is incorporated herein by reference as a part of this specification. It is to'be understood thatjthese motor'stop contacts may be designed to be normally open and V,

to stop the motor on'being closed.

A modification of the invention is shown in Figs. 4 and 5. In this modification, a small plate" 3 is attached to the end 415 of arm 414 of T-lever ve'dly secured to extension 418 by the adjusting screw 41! is anarm S which ten'ds to bepulled upward toward arm I by aretractivecofled spring 4 thereby biasing T-lever 444 so that the plate 3 will not rub on the arm I.

Since the adjusting screw 41! is located im'niediately beneath extension 534 of arm I ofthe function lever 4III, lever 48I can not 'move for wardat this its extension "4 is" held up aslong as plate I is held up by arm I. I The motor stop function lever 48I is thus 112- strained from operating at this time.

With this modification of theinv'ention, when a blank" signal is received, the movement of the vertical arm 41! of T-lever 461 moves T-lever 444 to the left as was described above. When T-lever 444 moves to the left, plate 3, which is secured to the end 415 of arm 414, moves to the left a distance sufficient to allow plate 3 to clear the arm i. Plate 3 and arm 414 are now free to move downward below arm I thereby conditioning the device for downward movement of extension 534 and arm 506 01 the function lever 48!.

The operator at station A now transmits a so-called shift signal. In response to the reception of this shift signal, the sixth vane 50 of the teletypewriter T1 will move to tilt its front end downward as is described in the Morton et al. patent. The sixth vane 50 is thus placed in the proper position for allowing the motor stop function lever "I to move forward to its operated position.

The operator next transmits the third code signal which may be another "shift signal as described in the Morton et a1. patent, or, more preferably, a preassigned signal such as H as described in the Watson patent supra. The selecting mechanism in the teletypewriter Tl responds to this code signal and effects the selection of the motor stop function lever 48l which operates and rotates clockwise on its pivot I16 thereby moving arm 506 downward and carrying with it the extension 534 and the adjusting screw 419 on extension 418 of arm 4'" as is shown in Fig. 5.

As is described in the Morton et a1. patent, the operation of the motor stop function lever 48l moves its other arm 505 upward thereby causing the extension 509 to strike against the end 50I of the contact operating lever 499 which, consequently, rotates clockwise on its pivot I16. In rotating, lever 499 moves its other end 503 downward to allow contact 491 to open thereby effecting the opening of the energizing circuit of motor M with the consequent stopping of motor M. The energizing circuit of the motor M will now remain open until the operator at station A transmits a start signal to close contact 491 and start motor M, such as in the manner described in the Morton et a1. patent, supra. Then, when the universal function bar 490 operates as described above, T- lever 444 will be pulled to the right thereby moving plate 3 to the right also. Since spring 4 tends to pull T-lever 444 upward against the stop screw 2, plate 3 will now be restored to its normal position immediately overhanging arm I as shown in Fig. 4.

As was stated above, the invention is not limited to the use of "blank and upper case H signals, but may be adapted to operate in response to any other combinations of teletypewriter signals. It is also to be understood that the invention is readily applicable to attended teletypewriters. Various other modifications may be made in the invention which is to be limited only by the claims appended hereto.

What is claimed is:

1. A teletypewriter system having in combination a first teletypewriter station, a second teletypewriter station, a telegraph line for connecting the two stations, a motor at the second station.

for operating the teletypewriter thereat, a circuit for energizing the motor, a control contact connected in series with the energizing circuit for opening and closing said circuit, motor starting means for closing the control contact, motor stopping means for opening the control contact, said motor stopping means comprising a lever for efiecting the opening of the control contact, a

latch for preventing the lever from effecting the opening of the control contact, and an instrumentality responsive to the reception by the teletypewriter at the second station of a preassigned permutation code signal for unlatching the latch for permitting operation of the lever.

2. A teletypewriter system having in combination a first teletypewriter station, a second teletypewriter station, a telegraph line for connecting the two stations. a motor at the second station for operating the teletypewriter thereat, a circuit for energizing the motor, a control contact connected in series with the energizing circuit for opening and closing said circuit, motor starting means for closing the control contact, motor stopping means for opening the control contact, and operating means for operating the -motor stopping means, said operating means being responsive to the reception by the teletypewriter at the second station of three different successive permutation code signals transmitted over the telegraph line by the teletypewriter at the first station.

3. A teletypewriter system having in combination a first teletypewriter station, a second teletypewriter station, a telegraph line for connecting the two stations, a motor at the second sta tion for operating the teletypewriter thereat, a

circuit for energizing the motor, a control contact connected in series with the energizing circuit for opening and closing said circuit, motor starting means for closing the control contact, motor stopping means for opening the control contact, said motor stopping means comprising a lever for effecting the opening of the control contact, a latch for preventing the lever from efiecting the opening of the control contact. an instrumentality responsive to the reception by the teletypewriter at the second station of a preassigned permutation code signal for unlatching the latch for permitting operation of the lever, and means for restoring the latch to its latched position.

4. A teletypewriter system having in combination a first teletypewriter station, a second teletypewriter station, a telegraph line for connect ting the two stations. a motor at thesecond station for operating the teletypewriter thereat, a circuit for energizing the motor, a control contact connected in series with the energizing circuit for opening and closing said circuit, motor starting means for closing the control contact, motor stopping means for opening the control contact, said motor stopping means comprising a lever for effecting the opening of the control contact, a latch for preventing the lever from eflfecting the opening of the control contact, an instrumentality responsive to the reception by the teletypewriter at the second station of a preassigned permutation code signal for unlatching the latch for permitting operation of the lever, and means responsive to certain preassigned permutation code signals for restoring the latch to its latched position.

5. A teletypewriter system having in combination a first teletypewriter station, a second teletypewriter station, a telegraph line for connecting the two stations, a motor at the second station for operating the teletypewriter thereat, a circuit for energizing the motor, a control contact connected in series with the energizing circuit for opening and closing said circuit, motor starting means for closing the control contact, a motor stop function lever for eifecting the opening of the control contact, and a blocking leverfor preventing the motor stop function lever from efiecting the opening of the control contact.

6. A teletypewriter system having in combination a first teletypewriter station, a second teletypewriter station, a telegraph line for connecting the two stations, a motor at the second station for operating the teletypewriter thereat, a circuit for energizing the motor, acontrol contact connected in series with the energizing circuit for opening and closing said circuit, motor starting means for closing the control contact, a motor stop function lever for effecting the opening of the control contact, a pivoted blocking lever for preventing the motor stop function lever from efiecting-the opening of the control contact, and means for swinging the blocking lever about its pivot to release the motor stop i'unctionlever ,for operation.

7. A teletypewriter system having in combination a first teletypewriter station, a second tele typewriter station, a telegraph line for connecting thetwo stations, -a motor at the second station for .operating the teletypewriter thereat, a circuit for energizing the motor, a control contact connected inseries with the energizing circuit for opening and closing said circuit, motor starting means for closing the control contact, a motor, stop function lever for eflecting the openingof the control contact, a pivoted blocking lever for preventing the motor stop function lever from effecting theopening of the control contact, and means responsive to the reception by the teletypewriter at the second station of a.

preassig'ned permutation code signal for swinging the blocking lever around its pivot to release the motor stop function lever for operation.

8. A teletypewriter system having in combination a first teletypewriter station, a second teletypewriter station, a telegraph line for connecting the two stations, a motor at the second station for operating the teletypewriter'thereat, a circuit for energizing the motor, a control contact connected in series with the energizing circuit for opening and closing said circuit, motor starting means for closing the control contact, a motor stop function lever for effecting the owning of the control contact, a two-position lever having an operated position for preventing operation of the motor stop function lever, a catch for holding the lever in its operated position, and means for releasing the catch.

9. A teletypewriter system having in combination a first teletypewriter station, a second teletypewriter station, a telegraph line for connecting the two stations, a motor at the second stacatch for holding the lever in its operated position, means for releasing the catch, and means responsive to the reception by the teletypewriter at the second station of a preassigned teletypewriter signal i'or releasing the catch.

' 10. A teletypewriter system having in combination a first teletypewriter station, a second teletypewriter station, a telegraph line for connecting the two stations, a motor at the second station for operating the teletypewriter thereat, a circuit for energizing the motor, a control contact connected in series with the energizing circuit for opening and closing said circuit, motor starting means for closing the control contact,

a motor stop function lever for eilecting the opening of the control contact, a two-position lever having an operatedposition for preventing operation of the motor stoprfunction lever, a catch for holding the lever in its operated position, means for releasing the catch, and restoring means for restoring the catch for placing the two-position lever in its operated position.

I 11. A teletypewriter system having in combination a first teletypewriter station, a second teletypewriter station, a telegraph line {for connecting the two stations, a motor at the second station for operating the teletypewriter thereat, a circuit for energizing the motor, a control contact connected in series with the energizing circuit for opening and closing said circuit, motor startingmeans for closing the control contact, a motor stop function lever for effecting the opening of the control contact, a two-position lever having an operated position for preventing operation of the motor stop function lever, a catch for holding the lever in its operated position, means for releasing the catch, means responsive to the reception by the teletypewriter BURDE'I'IE STEVENS SWEZEY.