US759492A - Telephone-exchange. - Google Patents

Description

PATENTED MAY 10, 1904.

C. A. ANDERSON.

TELEPHONE EXCHANGE.

APPLICATION FILED DEC. 5, 1901.

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APPLIUATION FILED DEG. 6, 1901.

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APPLICATION FILED DBO. a, 1901.

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UNITED STATES Patented May 10, 1904.

CLARENCE A. ANDERSON, OF SALINA, KANSAS.

TELEPHONE-EXCHANGE- SPECIFICATION forming part of Letters Patent No. 759,492, dated May 10, 1904.

Application filed December 5, 1901. Serial No. 84,761. (No model.)

To all whom it may concern.-

a citizen of the United States of-America, and

a resident of Salina,county of Saline, and State of Kansas, have invented certain new and useful Improvements in Telephone-Exchanges,

of which the following is a specification.

My invention relates to telephone -ex-l changes, and has for its ob ect improvement in party-line exchanges.

More particularly, it relates to-the switching mechanisms at the local telephone-stations and to the electrical connections at the.

local stations and the central ofiice whereby particular subscribers on the same party-line are selected from the whole number on the line and are placed in communication with each other.

In the accompanying drawings, Figure 1 is a plan of the switching mechanisms located at the local stations.

on line 3 3 of Fig. 1. Fig. 4 is a diagram showing a central oflice and one local station. Fig. 5 is a diagram showing two additional stations, and Fig. 6 is an enlarged elevation of the switch at the central oilice.

In Fig. 1, S is a ratchet-wheel pivoted on a post S and normally held against a stop S by means of the spring S. Secured to the wheel S is an insulated contact-maker 26, and in the path of 26 are two contact-points 27 and 43. The contact-point 27 is one step of the ratchet-wheel from the normal position of contact-maker 26; but the point 43 is a different distance for each switch on the partyline. For the first telephone it would be one step from 27 and two from the normal position of 26, and for each succeeding telephone it would be moved one step farther away.

Also secured to the wheel and in electrical connection therewith is a second contactmaker 55, and in the path of 55 are three contact- strips 54, 64, and 66, which are supported on an insulating-block J. The strips 64 and 66 are on a level, so that when the contact-maker 55 touches one it also touches the other. The strip 54 is thin and flexible and lies between and slightly above the strips 64 and 66. The end of the strip 54 adjacent to Fig. 2 is a section on line I Fig. 3 is .an enlar ed sectlon the normal position of 55 is bent downward, Bert known that LOLARnNon A. ANDERSON, 1

as shown at 540, and rests on the blockJ below the surface of the strips 64 and 66. The block J is built up, as shown at J, at the ends of the strips 64 and 66 on each side of the end of strip 54, so that the end of the latter strip rests in a groove. The contactmaker is also thin and flexible, so that when it is moved from its normal position it rides up over the part of 540 of the strip 54. At its extreme movement from normal position the contact-maker 55 drops oil of the strip 54 and rests on the strips 64 and 66. On its return to its normal position the contact-maker 55 passes under the flexible strip 54, and just before it reaches its normal position it raises the loose end and stops clear of all three strips. The movement of the contact-maker 55 from its normal position is by means of an electromagnet and the return is by means of the spring S.

Adjacent to the wheel S are two magnets N and I, which are oppositely polarized.

These magnets are provided with a common armature N, pivoted at I and heldnormally in a mid-position by a spring N 011 the armature N is a pawl N, adapted to engage the teeth of the wheel S to move it when the magnet N is energized. Adjacent to the pawl N is a pin N. arranged so that when the magnet P is energized the said pawl will be lifted from engagement with the wheel. Also on the armature N is an insulated. piece 51,

adapted to come into contact with a contactpoint when the magnet P is operated.

Located at convenient places are the rnagnets A and B, having armatures A and B. 1

On the armature B is a holding-pawl B", adapted to engage the ratchet-wheel S and to be released therefrom when the magnet B is operated. Pivoted at E is a pawl E, held against a shoulder A on the armature A by a spring on the post E.

Pivoted to the pawl B" is a rod B, the other end of which is guided by a lug A on the armature A. The guided end of the rod B is supported close to the shoulder A and the pawl E. When the magnet A is operated so as to draw the armature A against the contact 62, the pawl E catches on the shoulder-A and holds the armature in its retracted position. It when the parts are in this condition the magnet B be operated, the rod B will push the pawl E OR of the shoulder A and permit the armature A to fall back away from the contact-point 62.

It will be evident that a simultaneous oper ation of the magnets B and P will release the ratchet-wheel S and permit it to be returned to its normal position by the springs, provided the said wheel had been previously moved. The electrical connections for operating these magnets pass through the strips 64 and 66 and are held by the contact-maker 55 during its return movement until just before reaching its normal position, when the connections are broken by the contact-maker passing from the contact-strips to the raised portion J of the block J. Upon breaking these connections the pawls B and N return to engagement with the wheel S. To prevent this engagement occurring before the wheel is stopped by the post S the strips 64 and 66 extend as near as practicable to the normal position of the contact-maker 55, though it is not essential that this be nearer than two or three steps, or even more, of the ratchetwheel S. The reason for this is that although the pawls bl and B instantly move toward engagement with the ratchet-wheel upon the breaking of the circuits through the magnets P and B they cannot be moved quickly enough to immediately catch the rapidly-returning wheel unless they are made very light and are adjusted very close to the teeth of the wheel when they are in their released position. To obviate the necessity of bringing the strips 64 and 66 very close to the normal position of 55 and to allow. for slowness of movement when the spring S becomes weak, the pawls B and N and the armatures to which they are connected are made heavier than absolutely necessary and when released are moved to a greater distance than absolutely necessary to cause such release. The distance the holding-pawl B is removed from engagement with the teeth of the wheel is determined by the position at which the magnet B is set when the mechanism is put together. The movement of the pawl N is similarly determined by the positions of the magnet P and the stop 50.

At the central office there is an arm 38, pivoted in the center and provided with insulated pieces 35 and 47 at its ends. In the path of the piece 35 are a series of contact-points 34, all of which are connected to one pole of a battery X. In the path of piece 47 is a contact-strip 48, connected to the other pole of battery X. Adjacent to contacts 34 is a strip 39, and adjacent to 48 is a strip 41, both of which are in the path of the central section of arm 38. Strip 39 is connected with strip 48, and strip 41 is connected with the contacts 34. In its normal position the arm 38 stands in the position shown in Fig. 4 and when moved makes connection with the -contactpoints '34 and the strip 39. hen the opposite end of the arm 38 is pressed during its rotary movement, the connection is broken at 34 and 39 and ismade with 41 and 48. The length of the strips 41 and 48 is greater than the length of 39, so that after the arm has been moved to a position beyond which it will connect to 39 it is still in a position in which it may be pressed into contact with 41 and 48. Also located at the central office are the usual devices of such an ofiice, including drop D, clearingout drop 97, generator G, inductioncoil K, transmitter T, keys, and other devices which will be readily understood by the later description. These devices are connected by wires, as shown in the diagram, and from the central oflice there runs a wire 10, to which are connected all of the local stations on the party-line. One feature of the present system is that this wire and the ground connection are the only connections between the several stations, central and local. The number of local stations on the party line is limited only by practical considerations of service, and each station is represented by a different contactpoint 34 at the central oifice. In addition to the switching mechanism previously described there are at each local station the usual apparatus, including generator (1, ringer Q, receiver R, induction coil K, and contacts and connections such as will become apparent in describing the operation.

The stations in the diagrams are marked No. 3, No. 4, and No. 5, and assuming that the subscriber at the station No. 3 wishes to talk to the subscriber at station N o. 5 then the operation will be as follows: Either before or after removing his receiver R he will turn the crank of his generator Gr, when a current flows as follows: G, 8, 9,10, D, 11,12,13,14, ground at central, to ground at station No. 3, 15, 16, G. This operates the drop D at the central oflice, whereupon. the operator there inserts the plug 98 in the jack 99, turns the arm 38 so that it contacts strip 39 and the piece 35 contacts the first point 34, and presses key 18. The subscriber also removes his receiver if he has not previously done so. Upon connection with the first contact-point a current flows as follows: X, 33, 34, 35, 36, 37, 13, 14, ground at the central oilice to ground at each one of the local stations on the party-line 15, N, 25, 10, 24., 23, 22, 21, 38, 39, 4.0, X. This is a current in the proper direction through the magnets N of the several local stations to operate them and results in the movement of each contact-maker 26 to the adjacent contactpoint 27. Then beginning at the receiver at station No. 3 the talking-circuit to the central office is as follows: E, 16, 15, ground, 14, 96, 17, 1s, 19, R, 15,20, 21, 22, 23,24,10, 25,26, 27, 2s, 29, H, 30, 31, K, 32, R. The subscriber at station No. 3 informs the operator at the central oiiice that he wishes to talk to station No. 5, whereupon she (the operator) moves the arm 38 so that 35 sweeps over the entire series of contact-points 34 and stops beyond the last one. During this movement she presses the arm to make contact with 41 and 48 after making contact with the contactpoints for stations N o. 3 and No. 5. In pressing the arm 38 she tilts it on its pivoting-post V, thereby raising the end 35 clear of the con tact-points 34 and the strip 39 and causing the end 47 to engage the strips 41 and 48. Upon releasing the pressure on arm 38 the spring V, which is attached to the lower face of the arm 38 and bears against the post V, returns the arm to the position shown in Fig. 6. At each contact with a point 34 acurrent is sent, as previously described, for the first contact-point 34, the result of which is that the wheels S of each station are advanced step by step. When contact is made with 41 and 48, the current flows as follows: X, 33, 41, 38, 21, 22, 23, 24, 10, 25, 26, 43, 44, 45, P, 15, ground, 14, 13, 37, 36, 46, 47, 48, 49, X. A branch of this current flows from 25 through N to 15; but as this is contrary to the polarization of N this branch is without effect on that magnet. The current through P closes 51 to 50, and as this occurs only at the particular station which has its contact-maker 26 on the contact-point 43 and as each station has this contact-point at a diiierent distance from the normal position of 26 it will be evident that this occurs at only one station at a time. As the contact-points 43 of each station are related to the contact-points 34 of the central oflice, it will be evident that the pressing of the arm 38 in the manner described will operate the magnets P only at stations No. 3 and No. 5. The closing of 51 to permits a current to flow as follows: Y, 50, 51, 52, A, 53, 54, 55, 45, Y. The current through A closes A to 62 and permits pawl E to hold this closed position. This occurs at stations No. 3 and No. 5 only. Immediately after stopping the arm 38 past the last contact-point 34 the operator presses key 58 and turns the crank of her generator, when a current flows as follows: G at central, 56, 57, 58, 59, 60, 14, ground to ground at station N o. 5, 15, 16, Q, 61, H, 29, 28, 62, A, 9, 10, 24, 23,22, 21 20,(:l. This current does not go through station No. 3, because the circuit has been broken at 61 by the removal of the receiver, and does not go through the other stations, because the magnets A at those stations have not been operated. Immediately upon hearing his bell ring the subscriber at station N o. 5 removes his receiver, when the talking-circuit between No. 3 and No. 5' is as follows: E of No. 3, 16, 15, ground, 15 of No. 5, 16, R, 32, K, 31, 30, H, 29, 2s, 62, A, 9, 10 to 9 or NO. a, A, 62, 28, 29, 30, 31, K, 32, B. When through talking, the subscriber turns his generator to send a current as follows: Gr, 8, 9, 10, 24, 23, 22, 21, 97, 36, 37, 13, 14, ground, 15, 16, G. This operates the clearing-out drop 97 and notifies the central oliice. Upon the previously-described movement of the arm 38 the last contact made by 35 on 34 moved all of the contact-makers at the local stations to a position where they would drop oil of the end of the contact-strips 54 and rest upon the strips 64 and 66. With the contact-makers 55 in this position and notiiied that the subscribers are through talking the operator presses the arm 38 so as to make contact with 41 and 48 and returns the said arm to its normal position. Upon making the contact a current flows as follows: X, 33, 41, 38, 21, 22, 23, 24, 10, 63 of each station, 64, 55, 45, P, 15, ground, 14, 13, 37, 36, 46, 47, 48, 49, X. This again closes 51 to 50, when a current flows as follows: .Y, 50, 51, 52, B, 65, 66, 55, 45, Y. This releases the holding-pawl B and as the driving-pawl N had been previously released by the operation of magnet P the switching mechanism is free to be returned to its normal position by spring S. The operation of B also causes the rod B to push the pawl E off of the shoulder A, thus permitting the armature A to fall back away from the contact-point 62. This series of actions occurs at each one of the local stations, because they are all in the same position and because they are all connected to ground and the party-wire 10.

What I claim is 1. In a switching mechanism, the combination with a ratchet-wheel, a magnet for moving it from its normal position, and a spring for returning it to its normal position when released, of a contact-maker secured to and movable with said ratchet-wheel, and three contact-strips, said strips being arranged so that when contact-maker is moved in one direction it is in electrical connection with one of said strips and when moved in the opposite direction it is in electrical connection with the other two strips.

2. A contact-maker and means for moving it to and from a normal position, contactstrips located in the path 01 said contactmaker and arranged so that when said contactmaker is moved in one direction it is in contact with one strip and when moved in the opposite direction it is in contact with a diiferent strip, a telephone-station at which said contact-maker is located and a wire extending to other stations, areceiver, electrical devices for connecting said receiver to and disconnecting it from said wire, connections fromsaid contact-maker to said electrical devices, and means whereby said devices are operated by electrical impulses sent through 'said contactmaker while in connection with said strips.

3. A series of switching mechanisms and magnets for moving them a prescribed distance from their normal positions, a receiver for each switching mechanism, a party-line, an electrical connection closed by each switching mechanism at different points in the length of IIO &

their movements whereby the associated receivers may be connected to the party-line, a second electrical connection closed by each switching mechanism at the terminal of its movement, and devices operated by electrical impulses sent through the last-named electrical connections for causing said switching mechanisms to be returnedto their normal positions.

4:. The combination with a series of switching mechanisms and means for moving them from their normal positions, of electricallyoperated devices for causing the return of said mechanisms to their normal positions, normally open contact devices connected to the devices for causing return movement and located at the extreme positions of the movements of the switching mechanisms, and means for closing said contact devices by the movement of said mechanisms.

5. The combination with a telephone re ceiver, a party-line wire, and a magnet for connecting said receiver to said wire, of a switching mechanism, devices for propelling it, a magnet for releasing it from its propelling device, two contact-makers carried by said switching mechanism one of which is arranged to close connections to the connecting-magnet and the other of which is arranged toclose connections to the releasing magnet, and means for sending electrical impulses through said contact-makers and their respective magnets.

Signed at Salina, Kansas, this 29th day of November, 1901.

' CLARENCE A. ANDERSON. Witnesses:

ELMO VVELCH, W. T. VVELoH.

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