US2023290A - Electrical transmission bank - Google Patents

Description

Dec.. 3, 11935. w. G. Rxc'E 2,023,290

ELECTRICAL TRANSMISSION BANK l Filed Jan. 5, 1954 3 Sheets-Sheet l LCI Dec. 3, 1935. w. G. RICE ELECTRICAL TRANSMISSION BANK Filed Jan. 5, 1954 3 Sheets-Sheet 2 3 .nu ,ww @o @J o 0. r 0 G o 5 6 W/ w @M A E 4 r.. o a y` .y k 4 n 5J W 7 r. w 3 w w 6 ws-L wl KJ e 5 Z Wl. v m.. imm... S Turn Dec. 3, 1935. W (g,l RICE Y ELECTRICAL TRANSMISSION BANK @A NN fizzle/@fo Waldo l ce 5 Sheets-Sheet 3 .BY im@ J Filed Jan. 5, 1954 Patented Dec. 3, 1935 UNITED STATES PATENT OFFICE Y 18 Claims.

This invention relates to electrical transmission devices and more particularly to relay devices for mutiple telegraphic reception and distribution over multiplex circuits, although it may be employed with equal advantage for other purposes.

It contemplates more especially the provision of electrical receiving relay banks having a comparatively low resistance or low energy drain so that their multiple connection to telegraphic or similar electrical systems will not impair signal transmission or reception.

Methods and devices now used to accomplish multiple reception involve or require rather extensive revision of the distributor and/or printer connections as well as modications of resistance values. This renders the installation expense of multiple reception and distribution prohibitive in that extensive modifications in resistance values and wiring of the original printer and/or distributor circuits. Except for isolated instances, multiple reception and distribution has not been practiced although there is a great and. important need therefor. Relaying of messages by manual reperforation for use with a transmitter at the receiving stations, is the substitute practice for automatic multiple reception and distribution which is expensive, involves much time, and entails additional labor which are factors that render multiple reception and distribution an important advance in electrical transmission and reception devices where such can be accomplished with equipment of the desired simplicity and flexibility and without entailing much time, expense or labor of installation.

For instance, the present invention provides for a simple, compact and inexpensive relay unit that can be connected between a distributor and printer in a multiplex setup by mere attachment of suitable plug and socket complements to the cut ends of the six wire channel. The relay unit has similar leads terminating in corresponding plug and socket complements so as to aiTord ready and instantaneous connection between the printer and distributor. Similarly the relay unit or plate may be readily detached with the printer circuits restored to their original circuit setup by simply coupling together of the plug and socket reviously attached to the severed wires of the multiple channel.

It should be understood that in multiplex setups that utilize a cord and plug connection between the distributor receptacle and the printer plug, the intermediate relay unit or plate is attachable by means of a cord terminating in an adapter plug. The adapter plug is a complement of the regular cord and plug provided between the distributor receptacle and the printer plug, thereby offering instantaneous attachment and detachment of the relay unit. Reference has been 5 made to multiplex circuits, but the relay unit embodying the features of the instant invention, is likewise readily adaptable to simplex and duplex circuits operated on the start-stop method and employing printers provided with an independent selector magnet for each selector circuit as commonly used on multiplex channels, thereby offering wide usefulness and general flexibility on various types of circuits for multiplex-reception.

One of the important features of this relay unit or transmission bank isin the provision of relay coils of nominal or exceedingly low resistance values as compared with the regular printer coil and other resistances comprising the total resistance of each printer circuit usually though not necessarily employing six coils in number. The relay armatures are instantaneously responsive to signal reception notwithstanding the low resistance of the coil windings. Tothis end, the relay coils are especially designed to give a maximum number of turns on a minimum length of wire, thereby holding relay resistances to trivial values and yet secure the desired power of response that relays the signals without distortion or destroying accurate transmission, multiple reception and redistribution. On selector circuits operating 250 milliamperes, series connection of one relay-plate as described supra, will reduce the current intensity by approximately two milliamperes. Five plates connected in series would reduce current intensity by about ten milliamperes which is still trivial in that such nominal variations leave unimpaired the Wide marginal surplus provided for safe operation.

After extensive experimental work it was observed that when relays were mounted in compact proximity and especially when mounted on an iron base gains and losses of pulses Ideveloped as a result of magnetic inductive coupling between adjacent relays. With a view of eliminating all tendency of chatter of the relay armatures as a result of the above referred to disturbances, a careful separation of the several relays and especially the avoidance of an iron mounting base are purposely provided for in the design herein shown. By observing these precautions in design, special devices for locking in of the contacts commonly applied to the iive selector armatures is rendered unnecessary, thereby adding to the simplicity of operation and design. Known relay banks employ greater current intensities through the armature contacts, thereby requiring wider gaps due to fact that two or more circuits feed through each contact. Furthermore, additional resistors and also condensers are required to overcome troublesome sparking tendencies. This is avoided in the present relay-plate by confining the selector relays t-o the operation of a single printer coil unit, this further adding to the simplicity and dependability of the present invention.

One object of the present invention is to provide a relay plate having coils of comparatively low resistance values or energy drain that avail the multiple connection of relay units to a channel without impairing signal transmission yand/ or reception and/ or redistribution.

Another object of the present invention is' to simplify the construction and improve the operation of singleplex and/or multiplex circuits for effecting multiple distribution or re-distribution of electrically transmitted signals. `Still another object is to provide an electrical `transmission bank of exceedingly low energydrain so that their connection in multiple units to a system will not impair signal transmission and reception over a simplex, duplex or multiplex system for eiecting redistribution over a plurality of signal transmitting channels.

A further object is to provide a simple device thatv enables the ready incorporation of additional printers and/or reperforators in any electrical transmission channel without the necessary modification of electrical circuits, resistance values or wiring changes in the original printer', distributor or reperforator connections.

A still further object is to provide a simple, compact and self-contained relay unit of such low energy drain so that single or multiple units may be readily incorporated without operation impairment in the receiving circuit of a signal trans-Y mission channel so as to aiTord multiple reception f and redistribution without entailing any appreciable expense, time or labor.

Still a further object is to provide a relay hav- -ing coils of nominal resistance values or low energy drain with sensitively mounted coil armatures that respond tol all variations in signal impulses.

for multiple reception and redistribution.

Other objects and advantages will appear from the following description of an illustrated embodiment of the present invention.

In the drawings:

Figure 1 is a plan View of a relay plate or transmission bank embodying features of the present invention.

Figure 2 is a sectional view taken substantially along line II-II of Figure 1.

Figure 3 is a sectional view taken substantially along line III-III of Figure 1.

Figure 4 is a sectional View taken substantially I along line lV-IV of Figure 1.

Figure 5 is a sectional view taken substantially along line V-V of Figures 1 and 3.

Figure 6 is a perspective view of a relay coil ar- Figure 9 is a conventional wiring diagram ofthe relay plate showing its connection to a distributor, there being a conventional showingof the plug for connection to the next printer.

Figure 10 is a conventional wiring diagram of the relay plate showing connections to a printer and distributor through adaptor plugs and sock- 5 ets so as to enable instantaneous connection to any type of system now in use.

The structure selected for illustration comprises a bottom plate E0 which is of square or rectangular configuration and preferably though not essentially of non-magnetic material such as bakelite or other insulating composition. In this instance, another plate II is disposed above the bottom plate I9, it being of similar size, shape and composition for spaced parallel support by a plurality of studs I2 which have lock nuts I3 with spacer collars I4 disposed therebetween to rigidly maintain the bottom and base plates I il and II in spaced parallelism. The spaced parallel bottom and base plates I@ and Ii serve to receive the wiring therebetween for connection to the instrumentalities to be hereinafter described.

- A bank of relays I5, in this instance six, are mounted on the base plate I l in lateral alignment proximate to an edge thereof. Each of these relays consists, in this instance, of two low energy drain coils I6 and I1 that have core rods i8 with threaded ends i9 receiving nuts 20 and 2I on either side of the base plate I I which serves as a support therefor. The top extremities of the core rods I8 have nuts 22 and 23 in threaded engagement therewith tc receive a substantially rectangular top plate 24 of insulation material therebetween to support the relay armature 25 as will appear more fully hereinafter. It is to be noted that flanged cylindrical sleeves 28 provided with exterior surface insulation, envelop the core rods I8 intermediate the lock nuts 20 and 22 which engage the base plate II and top relay plate 24. Lock nuts 2G and 2| alsoJretain 40 soft iron yokes orplates 20 and 2i connected to the core rods I S on both sides of the base plate !I. The sleeves 26 serve to sustain the coils wound over the peripheral insulating surfaces thereof with enameled copper Wire to define spiral convolutions 2.

The low energy drain coils I S and II preferably though not essentially are wound from number twenty-six (26) copper enameled wire that have a resistance of 40.2 ohms per 1000 feet. Eachl coil comprises substantially forty six feet or a resistance of 1.85 ohms per coil which is equal to 3.7 ohms for both coils I5 and I'I of each relay. These coils are specially designed to give a maximum number of turns on a minimum length of wire, thereby maintaining relay resistances to nominal or negligible values and still secure the desired power of response that customarily was thought to require relay resistances ap- 1 proximating one hundred forty ohms in single- 60 vleak to the ground.

Now, then, the relay armature 25 is, in this 75 instance, or 'key eniigrauon (figure 6) so as to present transversely aligned ears 28 and 29 with an intermediate ear 30 along the longitudinal median line of the elongated armature shank 3 I. The aligned ears 28 and 29 are provided with depending pins 32 for registry with apertures 33 provided in a transversely disposed plate 34 xed to the relay top plate 24 by means of a threaded stud 35. The top plate 24 serves as a support for the armature pins 32 which is a fulcrum for the relay armature 25. This arrangement provides a sensitive mount for the armature 25 which will respond to slight electrical impulses and be capable of delicate adjustment. An enlarged aperture 36 in the armature 25 enables access to the plate securing stud 35 b-y means of a. screw driver for adjustment purposes.

'I'he armature 25 is longitudinally slitted as at 36 to frictionally retain a contact screw 31 in a threaded aperture provided for that purpose. The contact screw 31 confronts a Contact terminal 38 mounted on the extremity of the top relay plate 24 for connection through a wire 39 to a tubular terminal jack 49 provided in a plug 4I. The plug 4I has sum-cient terminal jacks 46 for lead wires 39 coming from each of the armature contact terminals 38 on the bank of relays I5, there being additional terminals in the plug 4I as will appear more fully hereinafter. A coil spring 42 is anchored to a nut 43 in threaded engagement with an elongated stud 44 which extends upwardly through the base plate I I for attachment by means of a nut 45 in engagement therewith. A lock-nut 46 engages the spring adjusting nut 43 to preclude the accidental displacement thereof so that the tension in the spring 42 will not vary unless adjusted.

A rod 41 extends from the spring 42, it having the free extremity thereof provided with an enlarged head 48 for lodgment in an aperture 49 through a slitted lateral opening 59. The spring 42 normally urges the relay armature 25 in a counterclockwise direction (viewed from Figure 4) so as to eiect the separation of the screw 31 from its contact 38 when the relay coils I6 and I1 are de-energized. An adjustable limit stop screw 5I threadedly engages a slittedVp-late 52 supported above the armature 25 by a block 53 which is attached to the relay top plate 24, thereby precluding undue receding movement of the armature 25 from its contact 38. A spring plate or latch 54 is pivoted as at 55 to the armature 25 so as to engage the coiled spring extension rod extremity 48 for retention in the armature aperture 49 against accidental displacement through the slot 50 (Figure 6) and to insure a firm electrical connection. The convolutions 21 that are wound around the peripheral surfaces 26 of the cores I8 are connected so that the coils I6 and I1 of each relay I5 are in series with lead wires 56 and 51 constituting terminals of both coils I6 and I1, respectively, for projection through the base plate II. The bottom core nuts 2l which are in threaded connection with the core rods I8, serve to anchor the terminals of wires 56 and 51 of the coils I6 and I1. The lead wires '56 and 51 are disposed between the bottom plate I 0 and base plate II for connection to terminal jacks 58 and 59 carried by plugs 69 and 6I, respectively.

It is to be noted that the lead wires 56 are in electrical connection with terminal pins while the lead wires 51 are in electrical connection with tubular jacks 59 that are complemental to each other in conventional plugs 60 and 6I for telescopic engagement 'with corresponding pposite plug sections extending from the secondary distributor and printer as will appear more fully hereinafter. A small ammeter 62 is mounted on the base plate II for rapid and precision"A adjustment of the armatures 25 of the relays I5. The ammeter terminals 63 and 64 are in circuits with the resistors 65 and 66 through p-in jacks 61, 68, and 69 mounted on the base plate II. Interchanging the pin jacks 61 and 68 reverses the current through the meter 62 when a negative battery is employed in connection with the power source leads 16 and 1I which are in circuit with the relay contacts 38. Additionally, leads 10 and 1I are connected to the tubular jacks 12 and 13 provided in conjunction with the relay terminal Contact jack 46 in the plug 4I (Figure 9) for furnishing power to the standard secondary printer and/or reperforator. tion of the pin jack 69 shunts out meter 62 when not used for. adjustment purposes so that it is selectively incorporated in the relay circuits.

Another pair of pin jacks 14 and 15 are provid- Inser-` ed on the base plate II in the relay circuits,

the relays I5 being so grouped that resistance 65 is in circuit with the single sixth pulse relay I5 (extreme right in Figure 1 and extreme left in Figure 9) while resistance 66 serves the remaining ve selector relays l5 which operate the selector magnets on the secondary printers and/ or reperforators. These resistances 65 and 66 have an approximate resistance of 300 and 400 ohms and. serve to determine the current iiow through the relays I5. -Now, then, by interchanging the In short, this switching arrangement through pin jacks 61 and 68 reverses the direction of' current passing through the ammeter 62 when a negative battery constitutes the power source.

The single jack plug 69 is provided for shunting off the current through ammeter 62 when not being used for adjustment purposes. The switching arrangement through jack pins 14 and 15 is also provided for transferring the' ammeter 62 from the ve selector relay circuits to the six pulse relay circuit so that a single ammeter serves both the selector and operating circuits for testing all armature adjustments. To adjust the relay armatures 25, the tensions of the springs 42 are set, in this instance, for one ounce tension and permanently locked in position by lock-nuts 46 and not disturbed thereafter. When the relay plate IU-II is operated on a multiplex channel-the channel is rst set up as for local operation, the rst pulse locked in at the transmitter. The pulsating deflection of the milliarnmeter pointer 62 is then noted. Should the pointer deection b'e insufficient or less than an arbitrary reading of 125 milliamperes on the scale, then the contact screw 31 on the armature 25 is turned in a counterclockwise direction to close the air gap,

core ends 22-23 until the ammeter Ypointer der.

lection is at 125 on the meter 62. Similarly, the

. 70 ble Vadapter plug 89-99 is used wherever 'prig adjustment is made on each of the ve selector armatures 25'. The six pulse armature 25 adjust- `ment may be made at this time by switching the meter 62 into the sixth pulse circuit so that similar adjustment can be determined and made as before. However, the sixth pulse adjustment may be made at any time when the multiple channel is ready for actual operations. On stop-start keyboard distributors, adjustment is rnade by operating the various pulses singly by pressing down the key board distributor corresponding to each single pulse that is being adjusted. VThe air gap of the contacts is determined by gradually closing the back stop armature screw 5| until the contact screw 31 closes the gap or touches the contact `38 as noted on the meter swing to 250.` The screw 5| is then turned in a counter-clockwise direction for one quarter turn to procure the proper contact-gap adjustment. The plate I I is also provided with an exteriorly accessible cord 11 constituting an extension of the switch 16 for the purpose of disconnectingthe battery from the relay contacts 38 and the power to the secondary printer motor or solenoid coil. The cord extension 11 is used when the relay plate ID-II is completely confined by l a housing 18 with its telescopically engaged closure 19 so as to preclude access to the switch 16 for accomplishing the same purpose. It is to be noted that 'the irst iive relays I5 (viewed from the left in Figure l or from the right in Figure 9) are the selector relays which close the selector circuits for operating the selector magnets in the telegraphic printers and/or reperforators of standard or known construction. The sixth relay I5 (extreme right in Figure l and extreme left in Figure 9) transmits the pulse to the magnet or relay of the printer or reperforator (not shown) that initiates operation of the mainshaft orr the power instrumentalities thereof through a magnet or other actuator` that is now or 'in the future may be employed on telegraphic printing or reperforating equipment. This relay action is accomplished by connecting (plug 4I to the standard secondary printer or reperforator which is provided with a complemental plug attachment therefor) relay-plate plug 68 through its pin jacks 58 to the0 complemental tubular jacks 80 provided in a plug bodyf8| (Figure 9) which have lead wires 82 connected to a standard telegraphic distributor 83. Then, too, the plug body 6| through its tubular jacks 59 is connected with complemental pin jacks 84 provided in a plug body 85 which have lead wires 85 connected to the standard primary-printer 81, 'thereby placing the printer coils 88 in circuit Vwith the relay coils 2? so that the desired number of additional secondary printers and/or reperforators may be placed in series through relay plates |0-I I by establishing connection with their respective plugs 4| to function simultaneously with the primary printer and/or reperforator. This same circuit connection of the relay plate I U-I I with the primary distributor 83 and printer 81, is shown in Figure l having a double adaptor plug 89 and 98 which establish detachable connection with the distributor 83 and printer 81 rather than resort to permanent tapping of Wires 82 and 86 with the distributor 83 and primary printer 81 as shown in Figure 9. The doumary printers or reperforators have cord and plug V connections with the distributor as standard equipment.

This relay-plate I 0-II with the wiring arrangements aiiord any desired number of message copies at one receiving station or permits the automatic transmission of the same message vby means of reperforated copy to any number of Ydifferent` stations through tape transmitters or by printer extensions to local or even remote loca-- tions.' `vFor each additional secondary printer or reperfrorator that produces a tape copy, a relayplate |0-|I of the type described supra may be incorporated into the distributor or primary printer circuit so long as the additional resistance thereof will not impair the operating margin of the current intensity required for the primary printer and/or reperforator and/or for the added secondary printers and/or reperforators. The feature of trivial resistance Values in the relayplate or bank design embodying features of the present invention, is of primary importance in that the series connection of a large number of the above described relay-banks to distributor circuits have proven successful. Trivial resistance values are made possible in a large measure by the precision adjustment aiorded by the test ammeter 62 and the sensitive mounting of the relay armatures 25 which enables the use of low resistance relay coils 21.

Where standard relay plates with a connecting frame are already in use, the plugs 68 and 5| with their lead wires 56 and 51 may be dispensed with", and exposed terminals 9|, in this instance sixteen, are provided in linear alignment proximate to an edge 92 of the base plate I I. To that end, the relay coil leads S and 51 are connected to the exposed terminals 9| which are designed to cooperate with resilient slip contacts 93 their exposed heads will be in frictional contactl therewith responsive to'complemental association therebetween. This is eiected by merely sliding the relay plate Iii-II into position on the connecting frame 95 with the relay-plate housing 18-19 removed or entirely dispensed with. The slip contacts 93 have lead Wires 82 and 85 connected thereto for attachment to the block 94, thereby establishing a series connection with the primary distributor 83 and printer 81 having the relay coils 21 in circuit therewith in the manner described in connecting with the plugs 69 and 6I, supra. `By resort to the connecting frame 94, the relay-plate -I may be utilized without any special plugs or other described connections, except for the plug 4I which establishes connection with the secondary printer and/or reperperforator.

Various changes may be made in the embodiment of the invention herein specifically described without departing from or sacriicing any of the advantages of the invention as dened in the appended claims.

I claim:

1. In a transmission bank for connection to the distributor of a telegraphic system or the like, the combination with a plurality of selector pulse circuits for connection to the coils of a primary receiving unit, of a power pulse circuit for connection to the actuator coil of the primary receiving unit, relays having low energy drain coils in said selector and power pulse circuits, and a plurality of secondary 'circuits for conveying the pulses of said selector and power pulse relays Cil to a secondary receiving unit for abusato fdistributionf the Asigr'ials received by said prnary receiving iinit without vappreciable current n ni'ft'ans'rnissi'lon bank forbonnection to the ibtoljof fa telegraphic system or the like, the cqlibiriatiohn with ,y vplurality of selector pulse cirtion to the coils that initiate the tien of a primary receiving unit, of a )j circuit for connection to the actuator ,at operates the mechanical mechanism of we primary receiving unit, relays having low enie'gy drain coils in said selector and power pulse circuits for operation without appreciable drain,

and a plurality of secondary circuits connected to the relay armature contacts for conveying the pulses of said selector and power pulse relays to a secondary receiving unit for duplicate recordation of the signals received by said primary receiving unit.

3. In a transmission bank for conneci-,ion to the distributor of a telegraphic system or the like, the. combination with a plurality of selector pulse circuits for connection to the coils 'of a primary receiving unit, of a power pulse circuit for con- 'jnectibn to the actuator coil of the primary receivunit-, relays having low'energy drain coils in 'said selector and power pulse circuits for operation without -appreciable drain and a plurality of secondary circuits for conveying 'the pulses of said selector and power pulse relays toV a second- Vreceiving unit for duplicate redistribution of the signals received by said primary receiving unit, said relays having coils of a resistance less than the resistance of the receiving unit to avoid impairment to the safety margin of operation of said primary receiving units.

4. In a transmissionbank for connection to the distributor of a telegraphic system or the like, the combination with a plurality of selector pulse circuits for connection to the coils of a primary receiving unit, of a power pulse circuit for connection to the actuator coil of the primary receiving unit, relays having low energy drain coils in said selector and power pulse circuits for operation without appreciable drain, and a plurality of secondary circuits for conveying the pulses of said selector and power pulse relays to a secondary receiving unit for duplicate redistribution of 4the signals re'ceived by said primary receiving unit, said relays having coils of such low drain characteristics that they do not impair the safety margin of operation of said primary receiving units.

5. In a transmission bank, the combination with a plurality of relays having low energy drain coils, of a corresponding number of primary pulse circuits including the coils of said relays for operation without appreciable current drain, a corresponding number of secondary circuits extending from the armature 'contacts of said relays and plug connectors having terminal jacks for receiving the ends of said primary and secondary circuit wires, said plug connectors establishing detachable connection of said pulse and secondary circuits with a telegraphic distributor constituting a primary receiving unit, and secondary re- 'ceiving unit for message duplication or redistribution responsive to the operation of said relays without appreciable current drain.

6. In a transmission bank, the combination with a plurality of relays having low energy drain coils, of a corresponding number of primary pulse circuits including the coils of said relays, a corresponding number of secondary circuits extending from the armature contacts of said relays and plug connectors having terminal jacks for receiving the ends of said primary and secondary circuit wires, said plug connectors establishing 5 detachable connection of said pulse and secondary circuits with a telegraphic distributor constituting a primary receiving unit, and secondary receiving units for message duplication or redistribution, one of said primary and secondary pulse circuits serving as a power pulse circuit for actuating the instrumentalities of said primary and secondary receiving units responsive to the operation of said relays without appreciable current drain.

'7. In a transmission bank for connection to the distributor of a telegraphic system or the like, the combination with a plurality of selector pulse circuits for connection to the coils of a primary receiving unit, of a power pulse circuit 20 for connection to the actuator coil of the primary receiving unit, relays in said selector and power pulse circuits, a plurality of secondary circuits for conveying the pulses of said selector and power pulse relays to a secondary receiving unit for duplicate redistribution of the signals received by said primary receiving unit, said relays having coils of such low drain characteristics that they do not impair the safety margin of operation of said primary receiving units with a plurality of secondary units in circuit therewith, and a current meter for connection tosaid circuits for testing the relay armature adjustments.

8. In a transmission bank for connection to the distributor of a telegraphic system or the like, the combination with a plurality of selector pulse circuits for connection to the coils of a primary receiving unit, of a power pulse circuit for connection to the actuator coil of the primary receiving unit, relays in said selector and power 40 pulse circuits, a plurality of secondary circuits for conveying the pulses of said selector and power pulse relays to a secondary receiving unit for duplicate redistribution of the signals received by said primary receiving unit, said relays hav- 45 ing coils of such low drain characteristics that they do not impair the safety margin of operation of said primary receiving units with a plurality of secondary units in circuit therewith, a

. current meter for connection to said circuits for 50 testing the relay armature adjustments, and means for switching said meter into said selector or power pulse circuits.

9. In a transmission bank for connection to the distributor of a telegraphic system or the like, the combination with a plurality of selector pulse circuits for connection to the coils of a primary receiving unit, of a power pulse circuit for connection to the actuator coil of the primary receiving unit, relays having low energy drain coils in said selector and power pulse circuits, pinshaped means for pivotally sustaining said relay armatures, and a plurality of secondary circuits for conveying the pulses of said selector and power pulse relays to a secondary receiving unit or units for operation without appreciable current drain for duplicate redistribution of the signals received by said primary receiving unit.

10. In a transmission bank for connection to the distributor of a telegraphic system or the like, the combination with a plurality of selector pulse circuits for connection to the coils of a primary receiving unit, of a power pulse circuit for connection to the actuator coil of the primary receiving unit, relays in said selector and power pulse circuits, pin-shaped means for pivotally sustaining said relay armatures, said relays having lo-w energy drain coils for operating said armatures without appreciable current drain, and a plurality of secondary circuits for conveying the pulses of said selector and power pulse relays to a secondary receiving unit for duplicate redistribution of the signals received by said primary receiving unit.

11. In a transmission bank for connection to the distributor of a telegraphic system or the like, the combination with a plurality of selector pulse circuits for connection to the coils of a primary receiving unit, of a power pulse circuit for connection to the actuator coil of the primary receiving unit, relays in said selector and power pulse circuits, pin-shaped means for pivotally sustaining said relay armatures, said relays having low energy drain coils for operating said armatures without appreciable current drain, tension springs for normally urging the relay armatures to one extreme limit of movement, and a plurality of secondary circuits for conveying the pulses of said selector andpower pulse relays to a secondary receiving unit for duplicate recordation of the signals received by said primary receiving unit.

12. In a transmission banky for connection to the distributor of a telegraphic system or the like, the combination with a plurality of selector pulse circuits for connection to the coils of a primary receiving unit, of a power pulse circuit for connection to the actuator coil of the primary receiving. unit, relays in said selector and power pulse circuits, pin-shaped means for pivotally sustaining said relay armatures, said relays having low energy drain coils of low resistance values for operating said armatures without appreciable current drain, tension springs for normally urging the relay armatures to one extreme limitvof movement, means for adjusting the tension in said spring, and a plurality ofV secondary circuits-for conveying the. pulses of said selector and power pulse relays to alsecondary receiving unit for duplicate redistribution of. the signals received by said primary receiving` unit.

13. In a transmission bank. for connection to the distributor of a telegraphicsystem or the like, the combinationwith a pluralityY of selector pulse circuits for. connection toY the coils of a primary receiving unit, of a power pulse circuit for connection to the actuator coil ofthe primary receiving unit, low energy drain relays in said selector andV power pulse circuits,v pin-shaped means for pivotally sustaining saidrelay armatures, an apertured plate fiXedtosaid-relay for fre-ely receiving said-pin-shaped armatureY sustaining means, and a plurality of secondary circuits for conveying the pulses of Ysaid selector and power pulse relays to a secondary receiving unit for duplicate recordation of the signals received byV said primary receiving unit.

14. In a transmission bank forl connection to the distributor of a telegraphic system-or the like, the combinationwith aplurality of'selector pulse circuits for connection to the coils of a primary receiving unit, of a power pulse circuit for connection to the actuator coi-l ofthe primary receiving unit, low energy drain relays in said selector and'V power pulseV circuits, pin-shaped means for pivotally sustaining said relay armatures, an apertured plate xed to said relay for freely receiving said pin-shaped armature sustaining means, limit means for adjusting the armature gap of said relays, and a plurality of sec ondary circuits for conveying the pulsesof said selector and power pulse relays to a secondary receiving unit for duplicate recordation of the signals received by said primary receiving unit.

15. In a transmission bank for connection to 5 the distributor of a telegraphic system or the like, the combination with a plurality of selector pulse circuits for connection to the coils of a primary receiving unit, of a power pulse circuit for connection to the actuator coil of the primary rel ceiving unit, low energy drain relays in said selector and power pulse circuits, pin-shaped means for pivotally sustaining said relay armatures, an apertured plate Xed to said relay for freely receiving said pin-shaped armature sustaining l' means, limit means for adjusting the armature gap of said relays, said relays having coilsv of low resistance values for operating said armatures without appreciable current drain, anda plurality of secondary circuits for conveying the pulses of said selector and power pulse relaysI to a secondary receiving unit for duplicate redistribution of the signals received by said primary receiving unit.

16. In a transmission bank for connection to nection to the actuator coil of the primary receiving unit, low energy drain relays in saidselector and power pulse circuits, pin-shapedmeans for" pivotally sustaining said relay armatures, an apertured plate xed to said relay for freely receiving said pin-shaped armature sustaining means, limit means for adjusting the armature gap of said relays, said relays having coils o'f-lo'w resistance values for operating said annatures without appreciable current drain, a plurality of secondary circuits for conveying the pulses of'said 40 selector and power pulse relays to a secondary receiving unit for duplicate redistribution of the signals received by said primary receiving unit, and a meter connection to said circuits for testing the relay armature gap adjustments.

17. In a transmission bank for connection to the distributor of a telegraphic system or the like, the combination with a plurality of selector pulse circuits for connection to the coils of a primary receiving unit, of a power pulse circuit for i apertured plate fixed to said relay for freely're`-A 5'5" ceiving said pin-shaped armature sustaining means, limit means for adjusting the armature gap of said relays, said relays having coils of low resistance values for operating said armatures without appreciable current drain, a plurality of secondary circuits for conveying the pulses of said selector and power pulse relays to a secondary receiving unit for duplicate redistribution of the signals received by said primary receiving unit, a meter connection to said circuits for testing the relay armature gap adjustments, and means for switching said meter into saidfselector or power pulse circuits.

18. In a transmission bank for connection to the distributor of a telegraphic system or the like, the combination with a plurality of selector pulse circuits for connection to the coils of a primary receiving unit, of a power pulsecircuit for connection to the actuator coil of the primary receiving unit, low energy drain relays in-said selector and power pulse circuits, pin-shaped means for pivotally sustaining said relay armatures, an apertured plate fixed to said relay for freely receiving said pin-shaped armature sustaining means, limit means for adjusting the armature gap of said relays, said relays having coils of low resistance Values for operating said armatures without appreciable current drain, a plurality of secondary circuits for conveying the pulses of 10 said selector and power pulse relays to a secondary receiving unit for duplicate redistribution of the signals received by said primary receiving unit, a meter connection to said circuits for testing the relay armature gap adjustments, means for switching said meter into said selector or power pulse circuits, and means for reversing the current ow through said testing meter when a negative power source is connected to said circuits.

WALDO G. RICE.

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