US722680A - Relay. - Google Patents

Description

PATENTED MAR. 17, 1903-. w. w. DEAN. I

RELAY.

APPLICATION FILED JULY 20, 1900.

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m w m No. 722,680; PATENTED MAR. 17, 1903 W. W. DEAN.

RELAY.

APPLICATION FILED JULY 20, 1900- no MODEL. 2 SHEETS-SHEET 2.

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UNITED STATES PATENT OFFICE.

WILLIAM W. DEAN, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE WESTERN ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

RELAY.

SPECIFICATION forming part of Letters Patent No. 722,680, dated March 17, 1903. Application filed July 20, 1900. Serial No. 24,339. (No model.)

To ail whom it may concern:

Be it known that I, WILLIAM W. DEAN, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Relays, (Case No. 34,) of which the following is a full, clear, concise, and exact description.

My invention is a relay adapted for response to pulsating or alternating currents such as are employed in calling over telephone-lines, and is designed especially for employment at substations of telephone systems to temporarily connect a polarized callbell with the line to receive the incoming signal when the relay is affected by such current.

The object of the invention is to produce a relay which shall maintain secure contact at its switch-points during the existence of the calling-current even though the latter may be of intermittent character, to be silent in its movement in response to the exciting-current, to be ofsimple and durable construction, and capable of accurate manufacture by means of simple processes.

My relay is designed especially for use in connection with a party-line telephonecircuit of four stations wherein the relay is connected in a bridge of the line-circuit at each station, together with a condenser, and serves when affected by calling-current to connect with one or the other of the line conductors should also be silent in its action in order that no sound may be made at those stations which are not intended to be called.

. The attached drawings illustrate my invention.

Figure l of the drawings is a diagram showing the circuits of the four-station party-line extending to a central office of a telephone system with means in the switchboard at the central office for selectively calling the different stations. Fig. 2 is a side elevation of my improved relay. Fig. 8 is an end view thereof. Fig. 4 is a plan, and Fig.- 5 is a sectional view showing the position of the armature with relation to the core.

I will first briefly describe the circuit arrangement in which the relay is designed to be operated.

The two line conductors 1 and 2 of the partyline circuit extend from the spring-jack a of the telephone-switchboard to each of the stations I, II, III, and IV. At each station a bridge 3 of the line-circuit is formed, which includes a condenser 19 and the magnet of the relay 0. This relay is of high resistance and is constructed to have specially high impedance in order that telephone-currents may not be diverted through it. It may have a resistance of two thousand ohms and may have fifteen thousand turns of wire upon it. Each of the relays controls the conection with the line-circuit of a call-bell, the bells at the different stations being designated 05, d (Z and C1 The bell d at station I is in a ground branch from the line conductor 1 and is polarized and biased to respond to positive current. The bell (Z at station II is likewise connected with line conductor 1, but is polarized to respond to negative current. Bells d and d at stations III and IV are biased for negative and positive current, respectively, and are connected from line conductor 2 in ground branches, which are controlled by the relays c at the same stations. Each station is also furnished with telephone instruments and a telephone-switch for connecting them with the line-circuit.

In the central office the calling-plug in the switchboard for making connection with the line by means of its spring-jack is connected with a series of calling-keys, which are adapted to apply pulsating currents of definite polarity to either of the two line conductors.

Thus the key 6 is arranged to apply positive pulsating current to line conductor 1 for operating the bell at station 1. Key 6 applies a negative current to the same conductor, while keys (2 and 6 apply negative and positive pulsating current to line conductor 2, respectively, for ringing the bells at stations Ill and IV. Each of the keys while applying current to one line conductor is arranged to ground the other line conductor, being thereby adapted to divert through the ground branches of the latter line conductor the current reaching that line conductor through the bridges at the different stations, so to prevent the ringing of bells not directly connected with the line conductor to which the calling-current is sent. Thus the line oonductors are normally free from ground branches which would tend to disturb the inductive balance of the telephone-line; but the act of sending calling-current in the line of any kind causes all of the relays c to connect the different biased bells to the line conductor, and thus permits calling-current to flow through the bell intended to be rung.

My improved relay is specially constructed to have a high impedance, and thus requires a good magnetic circuit.

A further characteristic is found in the armature of great inertia having a wide range of movement, whereby it is prevented from following the quick pulsations of the intermittent current and takes and maintains a definite position during the transmission of the intermittent calling-current.

The relay consists of a core f, with the wire f wound thereon, a return magnet-circuit or a pole-piece g, and the armature hof U shape. The downwardly-projecting ends of the U -shaped armature embrace extended pole-pieces and are pivoted at their lower ends on trunnions h h entering brass bearings g 9 sunk in the two sides of the polepiece g. The armature is made heavy to have great inertia, and by reason of the great length of its radius of movement it is capable of a wide range of movement without a great elevation of its center of gravity. The ends of the pole-piece g conform to an are drawn from the pivotal points g g so that there is no change of magnetic potential between the pole-piece and the armature during the movement of the latter. The polar extremity of the core f isinclined and curved to produce a gradual diminution of the resultant magnetic potential between the core and the armature as the armature approaches the core until the armature comes directly over the core, at which point the armature is subjected to only a very feeble force urging it to a further movement, the pull being directly downward. The tendency of the armature to tremble under the influence of alternating or pulsating currents exciting the magnet is thus reduced to a minimum. The movement of the armature is begun under the influence of a considerable attractive effort, which as the armature swings forward diminishes and changes in direction till nearly the whole effort of the magnet is directly downward, the armature being carried to this point by its inertia.

The heads of the magnet-spool are formed of square blocks t' and t", which fit closely within the space between the two extensions of pole-piece g. The upper extremities of the pole-piece are secured to the opposite sides of the block 'iby means of screws passing into the block. This head '1 carries two posts 7c it, which are covered with felt and which are located in position to form limitingstops for the movement of the armature h. The same block of insulating material carries the terminals of the magnet-spool.

The contacts of the relay consist of an adjustable contact-screw Z, passed through the flattened portion of the armature near its pivotal point, and the contact-spring m, carried upon a bracket '21, secured by screws passing through plates of insulating material to the pole-piece g, the spring and bracket lying substantially parallel to the armature h when the latter is in its attracted position. The bracket underlies the spring and forms a normal resting-stop therefor. A stud 0, secured in the bracket, passes through an opening in the contact-spring m and carries an adjusting-nut 0, which may be brought to bear against the spring to vary its tension.

When this relay is subjected to pulsating current, the armature starts gently from its resting-stop by reason of the feebleness of the attraction of the core over the great intervening distance. lVhen the armature has reached its forward position, the attraction upon it is downward and tends to produce no further forward movement, so that the pulsating current causes at most only a slight tremor of the armature. For these reasons the appliance is silent in its operation.

The contacts Z and m are located near the pivotal point of the armature and are closed in the initial movement thereof, so that they are firmly and continuously closed while the armature is attracted.

In the construction and assembly of the appliance the parts may be pressed from material in sheet form, with the exception of the core, and as the distance from the inner face of the armature to the pivotal points and the length of the core constitute the only dimensions which must be closely adjusted the parts may be readily assembled without liability to inaccuracy or defects in adjustment.

I claim as new and desire to secure by Letters Patent 1. The combination with a telephone-line extending from a substation to a central office, of a call-bell at the substation in a normally open branch, means at the central office for applying intermittent calling-current to the line, and a relay at the substation, said relay comprising a core f, a magnetizing-helix therefor included in the path of the callingcurrent, a U-shaped armature h of great inertia having its arms pivoted at their ends in the line of the core and normally lying in a plane inclined to the axis of said core, said armature being swung into the plane of the core when the magnet is excited, the yoke of said armature moving over the end of the core and relay-contacts closed by the armature controlling the normally open branch which contains the call-bell, whereby the armature maintains a definite position and holds the call-bell circuit closed during the transmission of the calling-current, as set forth.

2. In an electromagnet, the combination with the central core of the U-shaped polepiece 9 embracing the magnet-spool, the inverted- U shaped armature h pivoted near the heel-piece of the magnet, the arms of the armature and pole-piece lying side by side in parallel planes, the yoke-piece of the armature being adapted to move over the polar face of the core, as described.

3. The combination with a core, of the U- shaped pole-piece g embracing the core, the square spool-head t' of the core, the extremities of said pole-piece being secured to said head, and the inverted-U-shaped armature h pivoted near the yoke of the magnet, the 1 arms of said armature embracing the arms of the pole-piece and moving in parallel planes therewith, the yoke of said armature extending across the presented ends of the core and pole-piece, as described.

4. In combination, the core f and magnetwinding thereof, the U-shaped pole-piece g, the inverted- U-shaped armature h pivoted near the yoke of the magnet and carrying a contact near its pivotal point, and a flexible contact-spring therefor and the bracket secured to the pole-piece g carrying the said WILLIAM W. DEAN.

Witnesses:

ELLA EDLER, O. GROSENBAKER.

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