US2214910A - Start-stop repeater system - Google Patents

Description

| M. POTTS START-STOP REPEATER SYSTEM Sept. 17, 1940.

Filed Dec. 16, 1937,

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Patented Sept. 17, 1940 UNITED STATES PATENT OFFICE START- STOP REPEATER SYSTEM Louis M. Potts, Evanston, 11]., assignor to Teletype Corporation, Chicago, 111., a corporation of Delaware Application December 16., 1937, Serial No 180,066 12 Claims. (01. 178-70) This invention pertains to regenerative teleis placed under mechanical control of a device graph signal repeaters and more particularly to responsive to received line signals, while the retelegraph repeating devices of start-stop repeater is in its stop or idle condition, and in generative type in which reproduction of signals which each of the signal impulses is repeated by is eflected by a photo-electronic system. a photo-electronic device, which starts and stops 5 In systems for comparatively slow speeds of each retransmitted electrical signal impulse with transmission in which transmission is effected great suddenness despite any mechanical slugby comparatively long electrical impulses, an gishness of the mechanical parts which receive, ordinary electromagnetic relay having mechanistore, and control the received signal impulse.

l0 cally controlled electrical contact points may re- The above objects and features are attained 0 peat the impulses successfully, since the long by utilizing mechanical principles of start-stop electrical impulses have ample time to bring the selectors in combination with electronic retransconnecting transmission conductor to full elecmitting members so arranged that the retranstrically charged condition and thereby have time mitting members are controlled through a 15 to deliver to the electromagnetic relay an elecmechanical start-stop element to determine the 15 trical impulse sufiicient for its operation, wheretiming of retransmitted signal impulses and the upon the relay operates to renew the current retransmitted impulses are determined in markstrength of the individual signal impulses, and ing or spacing nature by a mechanically moved any distortion in comparative lengths of sucshutter element which exercises its optimum 0 cessive signal impulses will be negligible because photo cell control by a mid-portion of its moveit constitutes but a small portion of the total ment where its mechanical speed is relatively length of each signal impulse. rapid. The shutter element further does not Withincrease of speed in signaling, the inpropagate in any repeated electrical impulse any dividual electrical impulses become shorter, and electrical distortion resulting from any mechanithe invariable components of distortion introcal vibration or chatter resulting upon starting --duced by the electrical constants of the connecor stopping the mechanical shutter.

tive conductor and the mechanical constants of A system including this invention comprises a the repeating relay become a greater proportion controlling circuit having an eleotromagnet, a of a total signal impulse until a point is reached controlled circuit having photo-electronic control where distortion of the individual signal impulses, means, and a mechanical device controlled by 30 limits the speed of signaling, and to effect still the electromagnet and controlling the admission higher signaling speeds, it becomes necessary to of light to the photo-electronic means. While provide repeating devices which will not only restructure is disclosed for repeating in but one new the strength of the original signal impulse direction in the system shown, the apparatus is but will also restore the original relations of such that it is available as a structural unit for 35 impulse lengths. In consideration of mechanicircuit systems operating to effect transmission cally distorted signals, the feature of chatter in in both directions upon a single line. the contacts of a repeating relay is a form of The apparatus of the invention comprises mechanically produced distortion and operates to start-stop cams associated through a friction shorten the efiective value of repeated impulses clutch with a driving motor and with means for 40 unduly. holding the cams normally stopped, but subject Accordingly, an object of this invention is to to control of a starting signal 'in a controlling provide a regenerative repeater in which original line circuit. In response to a starting signal imelectrical conditions of controlling signals are pulse, the cams are started and continue in 5 faithfully repeated in a controlled circuit in motion for a complete cycle of revolution, which original time values as well as in renewed is also a complete code cycle of operation, and strength, and in which the beginning andending then the cams come to rest in readiness for the of the respective signals are effected with a next code cycle. minimum of transit time. Controlled by the cams is a shutter member for A still further object ofthe invention is the controlling the admission of light into a photo- 50 provision of a photo-electric regenerative repeatelectronic retransmitting member, the shutter ing device of simple construction and operamember being such that it is controlled bythe tion. cams for timing the instant of the beginning A feature of the invention is to provide a reand ending of every retransmitted signal imgenerative p e in w ch starting mechanism pulse, but is permitted by the cams to take a 55 transmitting position for each signal impulse in accordance only with the electrical nature of the instantly received signal impulse so that the beginning of each retransmitted impulse has its electrical nature controlled by the instant received impulse but has its beginning and duration controlled by the cams. A maximum abruptness in admitting and excluding light to and from the photo-e1ectric means is attained by mechanical construction of the shutter. The start impulse and the stop impulse, which respectively precede and follow the impulses of the intelligence code signal, also are repeated in regenerative manner.

A more complete understanding of the invention may be had from the following description taken in connection with the accompanying drawing wherein,

Fig. 1 shows a sectional view of mechanical elements of a structure illustrating this invention, taken on line l-l of Fig. 2;

Fig. 2 shows a sectional view of the mechanical elements taken on line 2-2 of Fig. 1;

Fig. 3 shows a section taken at 3--3 of Fig. 1 through the photo-electronic cabinet including a showing of an optical system and of a retransmitting circuit;

Fig. 4 shows an enlarged section of the shutter. and

Fig. 5 illustrates a simplified illuminating system.

Referring to Fig. 1, line wire I connects transmitting substation 2 and repeating signal receiving magnet 3 in a controlling circuit with grounded battery 4. Repeating mean is positioned between magnet 3 and amplifier I0, whence line wire 5 completes the circuit to receiving substation 6. Magnet 3 has an armature II pivoted to a supporting frame by pivot I2 with retractile spring I3 and an arm I4 which constitutes a follower for a six-toothed cam I5 fixed to cam sleeve I 8, which is sleeved upon a continuously rotating power shaft l'l. Shutter member 28, is pivoted about pivot rod I2 and ha a free end carrying a thin flat shutter I9 with slots l8 and is urged angularly by compression spring 2| extending between member and armature I I, and alternatively by compression spring 22 extending between member 20 and a lug 23 formed integrally upon arm I4. The member 20 is further positively controlled in position by engagement between a thin edge of member 20 and a similar thin edge of a lock lever 25, which is pivoted to the frame at 26, is tensioned by spring 21 and which constitutes a follower for a seven-toothed cam which is fixed with cam I5 upon cam sleeve I6. Retransmltting shutter member l9 has slots I8 which open or close slots 28 in cabinet 24 according to the position assumed by shutter member 28 and shutter I9.

Referring to Fig. 2, power shaft I'l carries a fixed collar 32 and a spring pressed feather washer 33 between which are friction discs 34 and 35 which hold frictionally a cam sleeve assembly comprising the sleeve I6, start arm 31, the sixtoothed cam I5, the seven-toothed cam 30, and a clamping nut 48. Start arm 31 engages gate 4| pivoted at 42 upon adjustable member 43, which is locked in position by clamp nut 44. Gate 4| is restrained by latch 48 pivoted at 41 upon the member 43 and tensioned by compression spring 48 extending from latch 48 to member 43. Extending between latch 46 and armature II of magnet 3 is a linkage comprising a start member 50 pivoted to the frame at 5| and engaging a plunger 52 sliding in frame part 53 and engaging at its upper end a projection 54 on armature ll.

Cabinet 24 is constructed to be light tight with the exception of a plurality of slots 28, and contains a photo-electronic cell 8 so positioned as to :be controlled by light reaching the interior of the cabinet through slots 28. In front of the cabinet is a thin shutter l8 carried upon member 28 and provided with a plurality of slots I8 which are related to slots 28 in such manner that in one position of shutter l9 all slots 28' will be obscured, while in the alternative position of shutter IS, a slot I8 will be positioned in alignment with each slot 28. The width of each slot 28 exceeds the width of each slot l8 so that a limited travel of shutter I9 b permitted before any slot l8 registers with its companion slot 28, and a similar amount of travel is permitted to the shutter l9 after the initial registration has been effected. This overtravel has the effect of permitting shutter 19 to attain a mechanical speed before the slots I8 cut off the light by passing the edges of the slots 28. This introduces into the retransmitted signal a delay but no distortion, since the mechanical delay in cutting of! the light can be adjusted to be equal to the mechanical delay in turning on the light. The shutter thus moves through three operating zones in each half-cycle of operation. Referring to Fig. 4 and taking center line 88 of slot I8 in shutter l9 as a moving line of reference, shutter I9, while moving the center line 88 downward through light zone 8| from position 82 to position 84, does not vary the illumination of photocell 8. While moving the center line 88 from position 84, where lower edge of slot I8 aligns with lower edge of slot 28, through zone 83 to position 88, where upper edge of slot i8 aligns with lower edge of slot 28, the shutter I9 changes the photo-cell 8 from lighted condition to darkened condition. The shutter moves the center line onward through dark zone 85 and engages a mechanical stop at position 88, after which any bounce or vibration which does not exceed the double width zone from 88 to 89 will not vary the dark condition of photo-cell 8.

The eflfect of shutter I9 upon photocell 8 is in-- creased by providing a plurality of slots l8, pro-' ducing a plurality of beams. The quantity of light supplied to photocell 8 is represented by a product of the width of slots l8 multiplied by the effective length of the slots. When a desired quantity of light has been determined, this quantity may be admitted to cabinet 24 by dimensioning properly the length and width of slots l8. Providing a plurality of slots resulting in a plurality of beams increases the effective length of the slots and reduces the required width thus the reducing movement required of the shutter I9. Since a minimum movement of shutter I9 facilitates its operation, the provision of nultiple slots is desirable.

An optical system is disclosed in Fig. 3 comprising an illuminant 55, a pair of condensers 56 and 51, and a collimator 58, which produces a beam 59 ample to cover all of the slots I8 and 28 when the slots are in alignment and which serves thus to control the photo-cell 8 at such times. a

Amplifier I0, Figs. 1 and 3, comprises valves 1 and 9, potentiometer resistor 60, and a system of three circuits; namely, a potentiometer input circuit for grid control of valve 9, a plate circuit for valve 9 which is at the same time a local potentiometer circuit for grid control of valve 1, and an output plate circuit connected to line 5 and substation 6.

The potentiometer input circuit comprises a portion of potentiometer resistance 60 as a source of current, contactor 6|, conductor 66, photocell 8, conductor 62, resistor 63, and contactor 64, with a potentiometer branch conductor 65 extending to grid of valve 9. Preferably, the resistance value of resistor 63 is so chosen that a maximum change in potential of conductor 65 results in response to a change in illumination of photo-cell 8. Adjustments of contactors 6|, 64, and H are such that current flows in the plate circuit of valve 9 when photo-cell 8 is dark, but

does not flow when photocell 8 is illuminated.

To produce this eifect, the grid of valve 9 is at all times negative with reference to cathode 61, being but lightly negative, due to proximity of contactors 64 and II, when photocell 8 is dark, and increasing in negative value when photocell 8 decreases in resistance by virtue of illumination.

The local potentiometer circuit mentioned for grid control of valve 1 comprises a portion of potentiometer resistance 60 as a source of current, contactor H, cathode 61 and anode of Valve 9, conductor 12, resistor 13, and contactor 14. When, by virtue of illumination of photo-cell 8 and resultant control of grid 68, there is no current in the plate circuit of valve 9, the potential of the grid 11 of valve 1 is of positive polarity with reference to the cathode 18 of valve 1 and a plate current flows in line conductor 5 of a value determined by position of contactor I4, constituting a marking signal current in substation 6. When, by virtue of a dark condition existing upon photo cell 8, current flows as described above in the local potentiometer circuit including valve 9 and resistor 13, a potential condition is established upon potential branch conductor 15 and therefore upon grid 11, such that the plate current of valve 1 is suppressed. In review, a signal of marking nature in a system including the invention exemplified in the drawing includes a marking signal current in the transmitting substation 2 and line conductor I, an energized condition of magnet 3, the shutter l9 in the position shown, slots I8 and 28 in alignment as shown in Fig. 3, an illuminated condition of photo-cell 8, estoppel of current in plate circuit of valve 9, and a plate currentin valve 1 constituting a marking signal current in line 5 and substation 6. For a signal of spacing nature, with shutter 19 closed and with photo-cell 8 dark, transmission is effected as follows:' Resistance of photocell 8 is at its higher value and potential from resistor 60 through contactor 64 and resistor 63 eifects a potential upon grid of valve 9 to render the valve conducting and the grid of valve 1 is rendered negative, rendering the plate circuit of valve 1 non-conducting and estopping current from line conductor 5, producing at substation 6 a signal of spacing nature.

In Fig. 5 an alternative illuminating system is illustrated, in which a concentrated illuminant 88 is positioned near the shutter I9 and the optical system is omitted.

The operation of the mechanical system is as follows: An interruption of current at transmitter 16 at substation 2 of the controlling line I will cause deenergization of signal receiving magnet 3, which will release armature ll permitting cam follower H to drop into the path of the six-toothed cam I5 and permitting the armature extension 54 to shift the plunger 52, which will operate lever 58 to cause operation, in turn, of latch 46, which will release gatell to release start arm 31, and thus to permit the rotation of cam sleeve I6 and its cams I5 and 30 by the power of shaft I1 through friction of discs 34 and 35. Operation of armature l I, when released by deenergized magnet 3, also compresses spring 2| and relaxes spring 22, but transmitting shutter member 20 resists the spring pressure because it is locked by lever 25, which is in the path of the seven-toothed cam 30, which cam now is starting. The first mechanical action of the cam sleeve l6 and its cams is to operate the lock lever 25 by cam 30 thereby releasing shutter member 20 which moves shutter l9 and repeats the signal from transmitting station 2 to the receiving station 6 by controlling the photo-cell 8, which in turn controls valves 9 and 1, which produces a spacing signal in line conductor 5, as described above. The operation of lock lever 25 is momentary because of the small arcuate dimension of the lobes of the toothed cam 30, and member 26 immediately is relocked. In operating to unlock the shutter member 20, looking member 25 permits release of the member suddenly at the instant when the end of lever 25 leaves the end of member 20. The impulse from station 2 now being repeated to station 6, thus has been determined in point of time solely by the movement of the cam 30 acting through lever 25 to release member 20, but its electrical nature whether a marking current in line 5, because valve 1 is conducting, or whether a spacing current in line 5, because valve 1 is non-conducting, is determined solely by the position of the armature II which has been controlled solely by the signal received in magnet 3 under control of station 2.

At this time, lever 25 again projects into the path of teeth'of cam 30, arm l4 projects into the path of cam l5, and the next action is the engagement of a tooth of cam 15 with its follower arm I l whereby armature II is moved toward or against its controlling magnet 3. This action occurs six times in a cycle, each such occurrence at about the middle of six of the code impulses; namely, first, second, third, fourth, and fifth impulses and the stop impulse of the code. In each instance, armature II will be heldby magnetism of energized magnet 3 if the instant signal be a closed circuit at station 2, but in each instance armature II will be released by the passing of tooth of cam l5 from follower arm 14 and armature II will be Withdrawn from deenergized magnet 3 by spring i3 if the instant signal at transmitting station 2 be such that the transmitting station 2 is open circuit to deenergize magnet 3. In each such instance, action of follower l4 byv cam l5 and retention or release of armature II by magnet 3 will be followed by operation of lock lever 25 by 'cam 38, which will permit shutter member 20 to operate the shutter to open or close the light cabinet 24 accordingly as magnet 3 has retained armature II or has released armature ll, urging shutter member 26 downward or upward when released by lever 25.

Thus there is provided a regenerative repeating mechanism having a small number of mechanical parts andno electricalcontacts, whose parts are controlled by electro-mechanical means and the motion of whose parts control the illumination or darkening of the photo-electric cell 8 in code manner in response to received signals.

The application of the photo-electronic retransmission has been made here with reference to a specific type of mechanical control device for operating the shutter member 20 and shutter l9. It will be understood that many modified forms of shutter and shutter controlling member may be designed to cooperate with variant forms of mechanical controlling devices.

What is claimed is:

1. In a regenerative repeater, signal receiving means, a photo-shutter having a closed and open position, means to determine the succession of open and closed positions of the shutter according to the operation of the signal receiving means, a rotary start-stop timing member started into rotation by said signal receiving means responsively to an initial signal of a group of signals, and means responsive to said timing member to determine the actual time of the change from open position of said shutter to close position of said shutter or vice versa, controlled by said timing means.

2. In a signal receiving system, means to transmit code signals, timing means started by said signals at the beginning of each code signal and operating independently for the remainder of the signal, a photo-shutter having an open and closed position, means controlled by the signal to determine the position of the shutter for each element of the signal, means to determine the time of change from open to closed and vice versa controlled by the timing means, means to produce a beam of radiant energy, means to modulate the beam by said shutter, a photo-electric cell activated by said beam, and means to transmit electric telegraph signals according to the activation of the photo-electric cell.

3. In a regenerative repeater, signal receiving means, means to produce and extinguish a beam of light under the control of the receiving means, means normally at rest and started into rotation by said signal receiving means in response to a starting signal to time the intervals between producing and extinguishing the beam, a photoelectric device activated by said beam, and means to transmit electrical signals controlled according to the operation of the photo-electric device.

4. In a telegraphic repeating device, an armature controlled by received electrical signals, a photo-electronic member having a shutter elastically articulated to said armature, and camcontrolled mechanism initially responsive to said armature and operating to' render said shutter operable by said armature ata predetermined instant.

5. In a telegraphic repeating device, an armature controlled by received electrical signals, a photo-electronic member having a shutter, elastic means connecting said shutter and said armature, and cam-controlled mechanism initially responsive to said armature and operating to render said shutter operable by said armature through said elastic means.

6. In a telegraphic repeating device, a signal receiving magnet, an armature for said magnet, a photo-electronic retransmitting member having a shutter, a tension member connecting said armature and said shutter to operate said shutter in response to movement of said armature, and a locking member engaging said shutter to restrain said shutter whereby an instantly received signal is stored in said tension member.

7. In a telegraphic repeating device, an armature controlled by successive received signals, a photo-electronic member having a control member elastically articulated to said armature, and cam-controlled mechanism rendering said control member responsive to said armature at successive instants of beginning of a plurality of electrical retransmission time intervals.

8. In a telegraphic repeating device, an armature controlled by successive received signals, a photo-electronic retransmitting member having a movable shutter, means selectively controlled by said armature and acting to urge said shutter to move, a locking member engaging and restraining said shutter, and means operating said locking member to release said shutter repeatedly.

9. In a telegraphic repeating device, an armature responsive to successive received signal impulses, a photo-electronic retransmitting member having a controlling shutter elastically connected to said armature to follow movements of said armature, and cam controlled mechanism engaging said shutter and restraining said shutter after said armature has been shifted and until a mechanically predetermined instant.

10. In a telegraphic repeating device, a receiving member responsive to received electrical signals, a photo-electronic retransmitting member controlled by said receiving member, a rotary member responsive to said receiving member to begin rotation, and means associating said rotary member and said retransmitting member to control said retransmitting member repeatedly during each rotation to begin retransmission of successive received signals.

11. In a telegraphic repeating device, a photoelectronic retransmitter, a timing member therefor, a restraining member engaging and restraining said timing member, an armature controlled by received signals, and means operated by said armature and acting to control said timing member and said photo-electronic retransmitter.

12. In a telegraph transmitting device, a photocell, a shutter controlling the illumination thereoi, and means to operate said shutter through a preliminary zone of motion prior to varying the illumination of said cell, through an intermediate zone of motion while varying the illumination of said cell, and through a final zone of motion after varying the illumination of said cell.

Louis M. ro'rrs.

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