US1387255A - Telephone-exchange system - Google Patents

Description

C. L. GOODRUM.

TELEPHONE EXCHANGE SYSTEM. APPLICATION FILED DEC. 3|, 1919.

1,387,255, Patented Mg. 9,1921.

Van for 6/2 air/es L Gaadrum UNITED STATE PATENT OFFICE.

CHARLES L. eoonmmr. OFNEW YORK, a. Y., Assicnon r WESTERN ,ntnc'rmc com:- rANy, mcoaroaunn, or ivnwvonx, N. Y.,-A CORPORATION or NEW'YORK.

TELErHoivE-EXcnANeE SYSTEM.

To all whom it may concern: 7

Be it known that I, CHARLES L. GooDRUM,

a citizen of the United States, residing at New York, in the county of New York and 'State of New York, have invented certain new and useful Improvements in Telephone Exchange Systems, of which the following is a full, clear, concise, andexact descripflt1on.

This invention relates to telephone exchange systems, and more particularly to circuit arrangements for selector switches employed in automatic and semi-automatic telephone exchanges.

In systesms employing automatic switching appa rtus for extending connections froma calling to a calledsubscriber, it is customary to control such switches by means of impulse-sending devices at the calling station. These impulse senders or calling devices are of various formsand are capable of sending impulses varying in character. Forexample, someimpulse senders are de signed to send a series of impulses corre-. sponding to the digit of the number desired 'in which all of the interruptions between said impulses are of equal length, while others are designed to send a series of im pulses in whichall oi the interruptions between impulses are of equal length except the last which is relatively longer than the preceding ones. An impulse-sending device of thelatter nature is disclosed in Patent No. 1,158,951 of November 2,1915, to A. H. Adams ct al. In the. well-known type of selector switch'a controlling relay for sending impulses to an operating magnetat each interruption'of the line circuitcoiiperates with a slow-to-release relay which is energizedat the first closure of the line circuit and remains energized during the sending of a se-' ries offiimpulses. In the common type of selector switch a second slow relay similar to the onementioned above isused to control aso-called side switch through the-me diuin of a "magnet, the sideswitch being advanced after each series of impulses to cliange local circuits in preparation for the hunting movements. .Difliculty has loeen experienced with the ordinary. selector switch when different type senders have been' used,

due to the stepping magnet oftheswitch not operating to step the switch in accordance with the digits setup at the impulse sender since, where the lastinterruption was longer than the preceding onesthe side switch employing the present invention.

7 Specification of Lettcrslatent, P t t d u 9, 92 Aplilication filed December 31, 1919. Serial No. 34 579. i ii WOIld operate'before the last'impulsewas I V e l l It is, therefore, an object of this invention to provide a new and improved'circuit arrangement for a selector switch, whereby the operation of the stepping magnet for setting the switch in relationto a group of trunk terminals-1s independent of the current impulses sent out by the impulse sender atthe calling station In the present embodimentof the inven tion, the stepping magnets for operating the selector sw tch are controlled by a relayin a local impulse circuit, which relay is in turn controlled in the directive selective movements of the switch by the line relay. The

- circuit arrangement is such that the impulse. relay is shunted during the closure of the line circuit, said shunt being broken a t eacli interruption duringthe sending of impulses, thereby permitting. the energizatlon of the impulse relay. Actuation of the impulse relay closes a circuitfor the stepping mag nets, which, in turn, at their contacts again form a short circuit path for the winding'of the impulse relay; 1 V

The drawings represent diagrammatically a portion of a telephone exchange "system Only so much of the circuit arrangements anda'pparatus is shown as is necessary. fora clear understanding of this invention I w The mechanical construction and the operation of the step-by-step selector switches and other apparatus used in building up a connection between a calling and called subscriber are well known to those skilled in the art, and therefore, in the present disclosure a detailed description will be given only of the operation of the selector switch utilized in the establishment of a connection.

; The subscriber at substation A, desiring tov establish a connection with substation B, removes hls receiver fromthe switchhook and causes a trunk. finder or line switch C, to

Relay at upon energiz'ation closes .a-circuit from ground through its right armature and release relay 11 to grounded battery. Re-

lay 11 upon energization prepares a circuit for relay 14 as follows: grounded battery, resistance 12, front contact and left hand armature of relay 11 and winding of relay 14 to ground. Relay 14 does notoperate at this moment due to its being shunted at its right armature and back contact and left armature and front contact of relay 4 to ground.

The calling subscriber now operates his impulse sender S, which may be of the type disclosed in the patent heretofore mentioned, to send a series of impulses over the line to cause the setting of the selector switch D. Upon the first interruption of the line. circuit, line relay 4 releases its armatures, thereby removing the shunt at its left-hand armature for relay 14, causing energization of the latter over the path heretofore traced. Energization of relay 14 establishes a circuit for primary stepping magnet 21, over the following path: ground, armature and front contact of relay 14, side switch wiper20 in its first position, winding of primary stepping magnet 21 to grounded battery. Upon energization of primary stepping .magnet 21, its armature is attracted and a'sliunt path is prepared for relay 14 as follows: grounded battery, resistance 12, front contact and left hand armature of relay 11, armature and-front contact of magnet 21, side switch wiper 50 and its first contact, and front contact and left-hand armature of ie lay 4 to ground; This shunt "path is complete'd at the endof the interruption of the line circuit, due to the armature of relay4 being attracted when the second impulse of current is sent over the line. This opera tion is repeated for all impulses of the series.

In accordance with the nature of the impulse sender herein referred to, thelast interru'ption in a series of impulses will be a comparatively long one which results in a comparatively long deenergization of the line relay and the closure of the back contact and right armature thereof to ground. This results in the energization of escape magnet 15 over the following path grounded battery, winding of magnet 15, side switch wiper 16, in its first position, resistance 17, front contact and right-hand armature of relay 11, back contact and right-hand arm-- ture of relay 4 to ground. Magnet 15 is of the slow-to-energize type and does not receive suflicient current during the preceding interruptions to "energize. As soon as the sending out of impulses ceases and the right armature of relay 4 is maintained attracted for a relatively long interval, magnet 15 is deenergized, thus moving the side switch brushes into position 2. Relay 14 was "enere g'ized and consequently energized :the (step;

"ping magnet 21, at the beginning of the interruption in the line circuit, so that the last directive movement ofthe switch was completed before the side switch was moved into position 2. In position 2 of the side switch wipers, primary magnet 211s d sconnec-tecland secondary magnet isfconnected tofground over,;.tl1e,, front contact andlefthand armature of relay 14, relay 14 having been energized over the following path: grounded battery, resistance .12, front con-- tact and left-hand armature of 'relay 11, winding'of relay 14 toground;

. Under the control of magnet 22, the wipersof the selector switch are stepped over the terminals thereof'until an idle trunk is reached. Assoon as testbrush 26 of the selector switch D reachesthe terminal of an idle trunk 27, to=which ground will b'e'c'onnected,'a circuit is closed from this ground through brush 26, side switch lwiper 16 in its second position, winding OfPmagnot 15 to grounded battery. The escape magnet 15 will again be energized causing the wiping apparatus (selector or connector) win be restored to normal, causing, ground to be placed uponrthe terminal 27, engaged by brush 26s This will close a circuit from ground through brush 26 side switch wiper 19 in itsthird positionyoff-normal i contact 40 and winding. of unease magnet 30 to grounded battery. Release'inagnet 30,11pon energization, closes. a locking circuit for itself from grounded {battery through itsw-indingand off-normal contact 40 and armature and. front contact to' ground. Under the control of release inagnet 30, theselector switclif-D and'the associated side switch will be restored: to normal, the locking circuit of the release magnet being maintainedclosed at its off-normal contact until selector switch Dhasbeen restored to its normal position?v After the receiver offl'tlle calling substation A has been replaced and the side isw'itch hasbeen restored tofnorinal, a groundzis I sent through the right-hand arinatures and back contacts of relays 4 and 11 through side switch wiper 31 in its first position to the-line or trunk finder C for causing the release of this switch." I Y Y 1 Should i the subscriber at" substation A abandon the call before sending out. impulses, he would ieplacehis receiver on the switch'hook, :and cause thereby the T deenergiz-ation-ofline relay 4 and slow release re- 7 tion.

after the first set of impulseshave been sent,

2'. 6., when the side switch wipers are in position 2, relays 4 and 11 would be deenergized and a circuit would be closed for release magnet 80 over the path previouslytraced which would cause the restoration of the se lector and line switch or "trunk finder to normal as heretofore described. What is claimed is:

1. In a telephone exchangesystem, incoIn-' ing and outgoing groups of lines, a selector switch for extendlng an incoming topan outgoing line, an impulse sender associated with said incoming line vfor sending a series of impulses 'thereover, a directively controlled magnet for setting said selector switch in operative relation to a group of outgoing lines, an automatically operatin magnet for moving said selector over lines in the selected group, a line relay responsive to closures in said incoming line circuit, a slow-acting relay energized during the sending of a series of impulses, an impulse relay for controlling the actuation of said dir'ectively controlled and said automatically operating magnets, a winding for said impulse relay,

means for shunting said impulse relay upon actuation of said line relay, means for energizing said impulse relay, and a shunt circuit for the winding of said impulse relay including contactson said magnets effective upon energization of said magnets for causing the deenergization of said impulse relay.

2. In a telephone exchange system, a line terminating in an automatic switch having primary and secondary operating magnets, an impulse sender forsending a series of impulses over said line, and three relays only for controlling the actuation of said magnets, oneoi'f said relaysbeingenergized during the sending of each impulse of current, another of said relays being energized during the sending of a series of impulses,

and the third relaybeing energized. during the intervals between impulses.

3. In a telephone exchange system, a line, an automatic switch, a stepping magnet therefor, an impulse sender for. sending a series of impulses over said line, a line relay responsive to each of the current impulses of a series, a slow acting relay energized during the sending of all the impulses of a series, an

impulse relay energized at each interval between impulses for controlling said stepping magnet, and means for, shunting the winding of said impulse relay upon its-energizar 4. The combination with a stepping magnet, of a stepping relay having an armature and contact for closing'a circuit energizing said stepping magnet, a winding for said stepping relay, a line circuit, a line relay, an impulse sender for sending a series of impulses over said line to said line relay, and a shunt for the winding of said stepping relay effective when said line. circuit is closed, said shunt being removed when said line circuit is interrupted. I

. 5; The combination with a stepping mag- .net, of a stepping relay having an armature and contact for closing acircuit for energizing said stepping magnet, a winding for said stepping relay, a line circuit, a line relay, a slow-acting relay, an impulse sender for sending a series of impulses over said line to said line relay, a shunt for the winding of said stepping relay effective when said line circuit is closed, said shunt being removed when said line circuit is interrupted, and a secondshunt for the winding of said stepping relay effective when said line circuit is closed and said stepping magnet is energized. a v

6. In a telephone system, an automatic switch having a plurality of operating magnets, a relay common to said magnets, means for associating the relay successively with I said magnets, means for intermittently energizing the relay to operate said magnets, and means operable by the V magnet associated with the relay to intermittently short-circuit the winding of the relay.

i. In a telephone system, a calling station,

.an automatic switch for extending a call therefrom, a line relay for said switch, a sender for said station for transmitting impulses to said line relay, a stepping relay, a circuit'controlled by contacts of said line relay completed for said stepping relay at the beginning of each impulse for operating said switch controlled by said stepping-re lay, and means for short-circuiting said stepping relay when said magnet operates.

8. In a telephone system, a calling station, an automatic switch for extending a call therefrom, a line relay for said switch, a sender at said calling station for intermittently interrupting a circuit including said line relay, stepping relay, a circuit closed for saidstepping relay at each deenergization ofsaid line relay, a stepping magnetfor said switch controlled by said stepping relay, and means for deenergizing said steppingrelay atthe end of each interruption in the circuit of said line relay.

In witness whereof, I hereunto subscribe my name this 30th day of December A. 1)., 1919.

, cnannns "L. coonn'UM.

. said stepping relay, a magnet for operating

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