US349975A - bickford - Google Patents

Description

(No Model.) 3 Sheets-Sheet 1.

J. H. BIOKFORD.

AUTOMATIC TELEPHONE EXCHANGE SYSTEM.

No. 349,975. Patented Sept. 28, 1886.

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3 Sheets-Sheet 2.

(No Model.)

Patented Sept. 28, 1886.

Wilif'EEEEE n. PETERS. Phola-Lflhognphar, Washmgmn. D. C.

(No Model.) 3 Sheets-Sheet 3. J. H. BIOKFORD.

AUTOMATIC TELEPHONE EXCHANGE SYSTEM. No. 349,975. Patented Sept. 28, 1886..

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N PETERS, Pholn-Lllhogmpher, Wiihingmn, D. C.

UNTTED STATES ATENT FHQEQ JOHN H. BHKFORD, OF SALEM, MASSACHUSETTS, ASSIGNOR OF ON F-THIRD TO S. FRED SMITH, OF SAME PLACE.

AUTOMATIC TELEPHONE-EXCHANGE SYSTEM.

SPECKFICATION forming part of Letters Patent No. 349,975, dated September 28, 1886.

Application filed NovcmbrrQS. 1885. Serial No. H3370. (No model.)

To all whom, it may concern.-

Be it known that I, JOHN H. BICKFORD, of Salem, county of Essex, and State of Massachusetts, have invented an-lmprovement in Automatic TclephoneExchange Systems, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

In telephone-exchange systems as now commonly constructed an operator is employed to make connections and disconnections; but in small cities and villages,where the number of subscribers is comparatively small, a central office employing an operator cannot be maintained, and it has been found desirable and commercially economical to construct a central office which shall be automatically operatcd to connect and disconnect the several subscribers lines one with another by the subscribersindividually. Variousappliancesand systems have been organized in furtherance of this plan, and by my invention I seek to improve and extend such plan,so as to render it more useful. \Vith this object in view I. have provided a central office containing a series of normally-groundcdinstrumentsoue instrument for each subscribci"s line leading from the said central oflicesaid instruments comprising suitable means, which, when brought into cooperation, removes the ground'terminals of the said instruments one by one at the will of the subscriber, and also establishes a connection with such other instrument as the subscriber may desire, the ground-terminal of the latter instrument being the final one removed. The instruments at the central office are each constructed substantially alike, are normally grounded and supplied with electro magnets in local circuits, said electromagnets, when energized, removing the normal groundterminals from the instruments. The instruments are interchangeably connected by mainline circuits,while the electro-magnets are also interchangeably connected with the said instruments by the local circuits. The instruments located at the central o'fliceone for each subscribers line-each consist of two fixed disks, each disk being composed of insulating material, and provided with a series of con ducting stops or surfaces, preferably about its periphery, while between the said disks a shaft rotatesin suitable bearings, said shaft supporting two pens or contact-pieces at opposite ends, which latter cooperate, respective] y, with the disks. The shaft also has mounted upon it a ratchet-wheel, which is moved step by step to rotate the shaft by a pawl fixed to a springcontrolled armature of a polarized magnet. One of the disks of each instrument having the 6 series of conducting stops or surfaces, preferably upon its periphery, while cooperating with the traveling pen or contact-piece, closes the local circuits, thereby operating suitable electro-magnets therein, removing the normal ground-terminals from the remaining instruments, one at a time, while the other disk, also having a series of conducting stops or surfaces, preferably upon its periphery, simultaneously cooperating with its traveling pen or contact-piece, connects the said instrument in circuit with the remaining instruments, one at a time, the subscriber controlling the movement of the ratchetnvheel, thereby dctermining how many steps shall be taken. 7 The instruments at the central office are each numbered to correspond with the line with whichitisiutimately connectcd,and the disks of each instrument are provided preferably with one normal or zero conducting stop or surface, and as many other conducting stops or sur faces as there are instruments or subscribers lines leading from the central office, the said conducting stops or surfaces of each disk being numbered alike and in rotation, commcnc- 8;, a

ing at the zero-stop, and the numbers or stops of each disk bearing corresponding numbers are interchangeably connected by electric cir cuits. The conducting stops or surfaces of each instrument bearing its own number, 0 counting from the normal or zero conducting stop,arealsonormallygrounded. Atthecentral office a main battery is also located, onepole of which is normally grounded, while from the other pole a battery-line leads beside a sub- 9 5 scribers line to the subscribers stations. Each subscribcrs station is supplied with a suitable call or signal box, and such other appliances as may be necessary. The call-box consists of a break-wheel having a pen or contact-piece connected with the battery-line, and arranged to co-operate therewith, but normally disconnected therefrom. The break-wheel is set in motion by a motor, and its shaft is supplied with a pointer, the end of which normally rests upon a contact piece, both the pointer and contact-piece being connected with the subscribers line. The break-wheel is preferably provided with as many notches or breaks as there are subscribers lines, and its pointer swings overa dialhaving the respective numbers marked thereon. The box is also provided with fingers or stops, which when brought into position over or at a desired number upon the dial limit the further rotation of the pointer, and consequently the break-wheel will only rotate until the pointer strikes the finger, remaining at rest until the finger or stop has been removed or returned to its normal position, when the break-wheel will continue and complete its rotation. When one of the stops or fingers is brought into position at a certain number and the motor started, the pointer leaves it contact-point, thereby opening the line behind it and rotates until it strikes the said finger, there stopping while connection is made with the subscribers instrument at the central office, and another instrument bearing the number corresponding with the number marked upon the dia at which point the finger is depressedgers or stops are pivoted at the call-box to a shaft, which latter is normally grounded, and

are supplied, whereby the fingers or stops at the call-box are returned to their normal position after-a subscriber has finished his conversation, which removal permits the pointer and break-wheel to complete their rotation, thereby, through the intervention of the polarized magnet, completing the rotation of the shaft of the instrument.

I have thus stated in a general way the salient features of this system, and I will now proceed to set forth and finally claim the es- I may, however, remark that, so far as I am aware,

sential features of my invention.

the polarized magnet, which is a very essential element of my system, has not heretofore been utilized in effecting the putting of subscribers automatically into connection in such systems of telephony.

Figure 1 shows a diagram of subscribers lines leading to a central office, a main battery in said central office, and battery-line; Fig. 2, a front elevation of one of the instruments located at the central office with which the subscribers lines are connected; Figs. 3, 4,

and 5, details to be referred to; Fig. 6, a portion The tin-' of the call or signal box, at the subscribers station, the face-plate being removed and the battery-line connected with the main battery at the central office, which latter is shown in diagram adjacent to the subscribers station;

Fig. 7 a similar view to Fig. 6, the face-plate being added, also a portion of themagnetobell and the subscribers line; and Fig. 8,-a

diagram of the central office, showing three instruments, indicative of three subscribers lines and the arrangement of the circuits.

It is designed by this invention that several subscribers lines may lead from a central office and be interchangeably connected by automatically-operated instruments at said central office, whereby the subscriber upon one line may automatically make connection with any other subscribers line leading from the central office. At the central office a main battery, B, one pole of which is normally grounded, is located, from which the batteryline leads to the several subscribers stations connecting with said central office, while the several subscribers lines converge at said central office, and by the intervention of suitable sulated from the shaft 1).

selecting-instruments are interchangeably connected. Each lineleading to the central office is provided with a selecting-instrument (see Figs. 2, 3, 4, and 5)which is normally grounded. The said selecting-instruments consist of two fixed disks, (L a, connected with uprights of a suitable frame-work, as A. The disks a a are made of insulating material, and are provided about their peripheries with conducting stops or surfaces, the disk at having a single series, as at a while the disk a has a double series, as at a a. The shaft b, mounted in suitable bearings in the uprights of the framework A, and between the disks a a, having rigidly connected therewith two pens or contact-pieces, b b", is rotated intermitt-ingly by means of a ratchet-:wheel, c, fixed thereon, which-is engaged. by a pull-pawl, 0', connected with the spring-controlled armature c of a polarized magnet, M, consisting of a permanent magnet having soft-iron cores connected with the poles thereof and insulated wire wound upon the cores. The pawl c is retained in engagement by a spring, 0 The pen I) is in- A retaining-pawl, 0*, is also provided to prevent the ratchet wheel from backward movement. As the shaft 2) rotates the pen or contact-piece I) wipes over the periphery of the disk a, touching the conducting stops or surfaces thereon, while simultaneously the pen I)", provided with a bifurcated end, wipes over the periphery of the disk a, and thereby touches both series of conducting stops or surfaces thereon.

The selecting-instruments just described, and for convenience lettered 0, located at the central office, and one for each subscribers line, are interchangeably connected by the subscribers wires, which connect the disks a of each instrument, the said wires being connected with the conducting stops or surfaces thereon, consequently each disk a is provided with as many conducting-stops a as there are subscribers lines, and also with one additional conducting-stop, upon which the pen I) norinally rests, which may be called zero. Each selecting-instrument is numbered to correspond with the number of the subscribers line with which it is intimately connected, as, for instance, referring to Figs. 1 and 8, the subscribers lines 1 2 3 connect intimately with the selecting-instruments 1 2 3, respectively, and the conducting-stops upon the disk a of the several instruments 1 2 3 will each be characterized by the numbers commencing at zero, as, forinstance, the next conducting-stop after zero of each disk at will be numbered 1, which upon instrument No. 1 will be its own number, while upon instrument No. 2 will be the conductingstop with which instrument No. 1 is connected with No. 2, and so on, while conducting-stop No. 2 upon instrument No. lwill be connected with instrument No. 2, and conducting-stop No. 2 upon instrument No. 2 will be its own number, as clearly shown in Fig. 8. At each instrument the conductingstop upon the disk a bearing the number of the instrumentitself is grounded at G, for purposes hereinafter explained. The disk a of each instrument is provided with a double series of conducting-stops, a" a", there being as many pairs as there are conducting-stops a" upon the disk a, and arranged at equal distances apart, so that the pens I) Z), travel ing by means of the shaft 1), simultaneously touch their conducting-stops. The disk c of each instrument is arranged similar to the disk a, in that it has a zero-point, and the pairs of conducting stops are numbered, counting from zero, the same as the conducting-stops upon the disk a. Local. circuits containing batteries F, and electro-magnets m, operating spring-controlled armatures m, which latter control the normal ground-terminals of each instrument, are connected interchangeably with the several pairs of conducting-stops upon the disks cof each instrument, similar to the subscribers lineconnections upon the disk a, that pair of conducting-stops of each disk a bearing its own number having no connection whatever, while the zero point or points over which the pens I) normally rest are insulated. As before stated, the several subscribers lines lead from the central office, and the subcribers stations are looped into the said lines, while a battery-line leads from the main battery 1- also located at the central oifice besidethe subscribers lines, and each subscribers station is also connected with said battery-line.

Referring to Figs. (3 and 7, the call or signal box by meansof which the instruments at the central office are automatically operated are shown, together with a portion of a magneto-bell, and it is obvious that such other applianees as commonly found at atelephone subscribers station may be located here also, and suitably connected in circuit, although not shown. Each call-box is provided with a break-wheel, D, set in motion, when desired, by any suitable motor and train of wheel work. The pen (I, connected with the batteryline, is arranged to co-operate with the breakwheel I), but is normally disengaged therefrom. A pointer, 1), is placed upon the shaft of the breakwheel 1), one end of which is connected with the wire 10, being a portion of the subscribers line, while its opposite end normally rests upon the contaetstud s, which is connected with another portion, 12, of the subscribers line, so that when the pointer is at rest the current will pass through the wire 12, poinlerp, and wire 10, thereby permitting any other box located in the same subscribers line behind it to transmitits signal.

Fig. 7 represents the box shown in Fig. 6, and the mechanism by which it is connected with the magneto-bell N, the main battery at the central station being shown adjacent to the box to more clearly illustrate the operation. The brealewheel D is supplied with as many notches as there are subscribers lines, or as there are instruments at the central office, and rotation of the break-wheel D connects the battery line with the subscribers line, and thereby sends an impulse to the central ol'lice for each notch or closure.which will depolarize the polarized magnet M, releasing its armature c,and thereby permitting the latter, aided by the force of the spring 50, to engage the next tooth ofthe ratchetwheel c, the openin of the line by means ofthe break-whcel 1) pel initting the magnet M to again attract its armature, and thereby pull the ratchetwheel cone tooth, and, as the ratchetwheel c is toothed to also correspond with the number of subscribers lines, a complete step-by-step process is carried out. Stops or lingers aone for each subscriberslineare connected with a rod, 12, at each eall-box,andarc eapablcofbei ngturned down into the path of rotation of the pointer p, to thereby stop the pointer p at that point. These stops or fingers are arranged at suitable distances apart correspomling with the notches of thebreak-wheel l),so as to retain the pointer p, and consequently thebreak-wheel D, at any desired pointal'ter it has caused a determined numberof impulses to be transmitted, the pen or contact-piece (l 'at the time the pointer strikes the linger or stop a being disengaged. The rod a isnormally grounded at G, 161' purposes to be hereinafter explained, and when the pointer strikes a certain fingeror stop,11,the subscribers lineis broken at the contact-stud 8, while the circuit from the ground G passes through the rod a, fingera, pointer 1), over the subscribers line 10. Each subscribers line leading from the central ollice terminates in a groundconnect-ion, as shown, in Fig. 1. After the pointer 1) has been retained by one of the lingers or stops at a sufficient length of timeto allow the subscriber to complete his conversation the subscriber hangs his telephone upon the lever r of the magneto-bell N, which draws the connecting-rod f downward, thereby rotating the crank f, turningthe shaft f ICC) which latter is provided with a flat strip,f", which strikes the fingers or stops at and returns them to their normal position, thereby permitting the pointer and its break-wheel D to completeits rotation.

The operation is as follows: Normally the circuit is from the main or subscribers line through the magnet M, shaft b, pen thence by wire 20 through the armature m to the ground. Should the subscriber upon line No. 1 desire to make connection with a subscriber upon line 3, he first depresses the finger or stop n, pointing to Fig. 3, marked upon the face of the call-box, then starts his motor, and the pointer travels forward until it strikes thefinger, when it comes to rest. In the meantime the break-wheel D is rotated sufficiently to cause the pin (Z to connect the battery-line with the subscribers line'three times, thereby sending three impulses. The impulses thus transmitted from the subscribers station are of opposite polarity to the polarized magnet M, thereby depolarizing it, repelling the armature, while the signalcurrent coming from any subscriber passes through the polarized magnet in a reverse direction, and being of the same polarity merely acts to attract the armature still stronger. Upon transmitting the first impulse the polarized magnet M by its pawl draws the ratchet-wheel 0 one tooth, thereby rotating the shaft b sufficiently to cause the pens b b to come in contact with the conducting stops or surfaces N0. 1, which being the number of the instrument, the current will pass from the subscribers line through the magnet M, shaft I), pen I), and thence to the ground G, the pen b", as previously stated,being preferably insulated from the shaft b. The second impulse causes the polarized magnet M to move the ratchet-wheel 0 another tooth, and thereby the pens I) b to come in contact with the conducting stops or surfaces No. 2, the current at this time passing from the subscribers line through the shaft and pen I) of the said instrument, the pen b closing the local circuit, thereby permitting the current to pass through the wires 22 23 24 25, cansing the magnet m to attract its armature and thereby remove the ground-terminal from the instrument No. 2, while the current leaving the pen I) of the first instrument will pass through the wires 26 27 28 29, pen I) of instrument No. 2, its shaft, and thence reversely through the polarized magnet M to the subscribers line No. 2, and the third impulse will cause a similar operation and connection of circuits at instrument No. 3 as the second impulse caused at instrument No. 2. Should the subscriber upon line No. 2 want to connect with subscribers lineNo. 1, the operation will be similar to that just described, the break-wheel rotating one notch, at which time the pointer will strike the finger No. 1, when the current will pass over subscribers line 2, through instrument No. 2, its pen b bearing upon the conducting-stop No. 1',

closing the local circuit, thereby removing the gronnd;terminal from instrumentNo. 1, and the current leaving the pen I) of instrument No. 2 will pass over the wire 30 31 32 20: through the penb of instrument No. 1, its shaft, and thence reversely through the polarized magnet M to the subscribers line No. 1. After the subscriber has completed his conversation he hangs the telephone upon the lever r of the magneto-bell, which, as previousl y described, returns the fingers or stops a to their normal positions, thereby releasing 1 the pointer, which then completes its rotation,

and through the intervention of the polarized magnet M at the central office causes the selecting-instrument to return toits normal position step by step. As will be readily seen,

the callbox at the station desiring to communicate being grounded, when the desired connection is made behind the magneto-bell, and other appliances a ground wire is completed over which conversation may be carried on.

I claim- 1. In a telephone-exchange system, the combination, substantially as herein set forth, of

a series of subscribers lines converging at a 1 main or central station, a selecting-instrument,

1 contact piece or pen, and means, substantially as described, for operating said mechanism fro m. a distance.

2. i In a telephoneexchange system, the combination, substantially as hereinbefore set forth, of a series of subscribers lines converging at a central or main ofilce, a selecting-instrument, substanti ally as described, including a polarized magnet for each subscribers line and located at the central office, said select- I ing-instrument containing a series of conducting stops or surfaces, a co-operating movable contact piece or pen and actuating-motor therefor for causing the contactpiece or pen to make connection with the said conducting stops or surfaces consecutively, said contact-piece normally resting upon a grounded conductingstop, while the remaining conducting-stops are interchangeably connected with corresponding conductingstops of the several selectinginstruments, with the exception of that conducting-stop which is characterized by the number of the selecting-instrument of which it forms a component part, which latter is grounded.

3. In a telephoneexchange system, the combination, substantially as hereinbefore set forth, of a series of subscribers lines converging at a central or main office, a selectinginstrument, substantially as described, for each subscribers line, and located at the central office, said seleeting-instrument containing a series of conducting stops or surfaces, a cooperating movable contact piece or pen and actuating-motor therefor, for causing the contact piece or pen to make connection with the said conducting stops or surfaces consecutively, said contact-piece normally resting upon a grounded conducting stop, while the remaining conductingstops are interchangeably connected with corresponding conductingstops of the several selecting-instruments, with the exception of that conducting stop which is characterized by the number of the selectinginstrument, of which it forms a component part,which latter is grounded; also a series of pairs of conducting stops or surfaces correspondinglyloeated with the former series of conducting-stops, those two pairs corresponding with the two grounded conductingstops being omitted, a local circuit connected with each remaining pair, and a contact piece or pen and actuating-motor therefor moved simultaneously with the contact-piece above mentioned, and arranged to make connection with the several pairs of conducting-stops consecutively, but normally disengaged therefrom, electromagncts in said local circuits and operating to remove the normal ground-terminal from the first mentioned contact-piece.

4. In a telephone-exchange system, the combination, substantially as hereinbefore set forth, of a series of subscribers lines converg ing at a central office, a normally-grounded selecting instrument, substantially as described, for each subscribers line, located at the central office, and interchangeably connected with each other, a movable contact piece or pen forming a co-operative part of the select-irig-instrument, a shaft, to which said contact-piece is attached, a ratchet-wheel, and pawl for rotating the ratchet-wheel, and a polarized magnet controllingthe operation of the said pawl and forming part of each selectinginstrument.

5. In a telcphoneexchange system, the combination, substantially as hereinbefore set forth, of a series of subscribers lines converging at a central or main office, a normallygrounded selecting-instrument. substantially as described,for each suhscribeflsline, located at the central office, and interchangeably e011- nected with each other, a movable contact-piece for each seleeting-instrument, and a rotary shaft carrying such contact-piece, a ratchet on said shaft, and a pawl co-operating therewith, and controlled by a polarized magnet, for intermittingly moving the said contact-piece to establish electrical connection between different pairs of the said selecting-instruments,and operating simultaneously with the said contact-piece for removing the ground-terminals from the several selectinginstruments eonsecutively.

6. In a telephone-exchange system,thecombination, substantially as hereinbefore set forth, of a series of subscribers lines converging at a central or main office, a normallymoving eontactpiece under the control of a polarized magnet for establishing electrical connection between different pairs of Selectinginstruments, a call or signal box at the subscribers station, containing a break-wheel and cooperating pen for controlling the movement of thepolarized magnet, and means, substantially as described, for stoppingthebreakwheel at any predetermined point during its rotation for an interval of time.

7. In an electric circuit, acall or signal box containing a motor, break-wheel, and co-opcrating pen or contact-piece normally disengaged therefrom, and connected with the battery-line, a pointer mounted upon the break wheel shaft,which latter is connected with the main line, a contact-stud, also connected with the main line, and upon which the pointer normally bears, aseries of normally-grounded stops, 11, arranged to be brought independehtly into the path of rotation of the said pointer, and against which the pointer strikes when rotated by the break-wheel, thereby determinin g at will the number of impulses transmitted by the break-wheel breaking the line behind the box and grounding the main line.

8. In an electric circuit, a call or signal boX containing a motor, break-wheel, and co-operating pen or contact-piece normally disengaged therefrom and connected with the battery-line, a pointer mounted upon the breakwheel shaft, which latter is connected with the main line, a contact-stud, also connected with the main line, and upon which the pointer normally bears, a series of normally -grounded stops, a, arranged to be brought independently into the path of rotation of the said pointer, and against which the pointer strikes when rotated by the break-wheel, thereby determining at will the number of impulses transmitted by the break-wheel, breaking the line he hind the box and grounding the main line, and means, substantially as described, for antomatically restoring the stop a to its normal position, permitting the break-wheel to complete its rotation.

9. An instrument for governing the transmission of an electric current over severalnormally grounded subscribers lines consecutively, which consists of a disk, a, having ase ries of conducting stops or surfaces about its periphery, a pen, I), and rotating shaft b, said pen normally resting upon that conductingstop through which the main-line is grounded, while the remaining conducting-stops are independently connected with the lines having the ground-terminals, a disk, 0/, having a se ries of pairs of eomlucting-stops about its periphery, a pen, I), having a bifurcated end and attached to but insulated from the said rotating shaft b, thereby moving sinuiltancously with the pen I), the said pen I)" normally resting upon an insulated portion of the disk a,

whilethe several pairs of conducting-stops are connected with local circuits containing local batteries and electromagnets, which, when operated, remove the normal ground-terminal at one end of the several subscribers lines consecutively, aratchetwheel, c, and pawl c, and means, substantially as described, for intermittingl y moving the said pawl, all as set forth.

10. In a system for telephonic communication, a series of subscribers lines leading to a central office, and having normal ground-terminals, a selecting-instrument, substantially as described,for each subscribers line, located at the central office, and interchangeably connected with each other, means, vsubstantially as described, intermittingly controlled by a polarized magnet, for establishing electrical connection with each of the several selectinginstruments consecutively and simultaneously removing the ground-terminals of each .subscribers line at the central office consecutively, commencing with instrument No. 1., and following in rotation until a desired number is reached, a call or signal box at each subscribers station containing a break-wheel,and

cooperating contactvpiece or pen normally, disengaged therefrom, and connected in circuit with amain battery, the break-wheel having as many notches as there are subscribers lines, a pointermounted upon the brealcwheel shaft, which latter is connected with the subscriber s line, while the pointer normally bears upon a contact-stud, also connected with the subscribers line, and means, substantially as described, under control of the subscriber,for stopping the rotation of the break-wheel at any desired point for a period of time, and grounding the subscribers line at the box in which the break-wheel is rotating, thereby controlling the intermittent operation of the polarized magnet and releasing mechanism for the break-wheel, that it may complete its rotation, all substantially as described.

In testimony whereofl have signed my name to this specification in the presence of two subscribing witnesses.

JOHN H. BIQKFORD.

Witnesses:

D. \V. GoocH, J. H. CHURCHILL.

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