US387889A - Multiple switch-board - Google Patents

Description

(No Model.)

M. G. KBLLOGG.

MULTIPLE SWITCH BOARD.

No..38`7,889. Patented Aug. 14, 1888.

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IlNiTnn dTaTns taTnNT @einen MIL() G. KELLGGG, OF HYDE BARE, ILLINGIS.

MULTIPLE SWITCH-BOARD.

SPECIFICATION forming` part of Letters Patent No. 387,889, dated August 14, 1888.

Application lcd June 6, 1387. Serial Nu/10,418. (No model.)

T0 crZZ whom t may concern,.-

Bc it known that I, MTLo G. KELLOGG, of Hyde Park, Illinois, haveinvented certain new and useful Improvements in Multiple Switch- Boards forTelephone-Exchanges, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying,` drawings, forming a part of this specification.

lily invention is designed to facilitate the work of switching at the central office of a telephone-exchange system; and it consists in multiple switch-boards for the erchange and independent local circuits and electric apparatus, wb ereby an operator at any board may readily determine whether the line of a subscriber called i'or is in use at either oi' the other boards, and is adapted to any of the known methods or combination of methods of sending in the calls or connecting` the terminal stations with or through the central office.

In my system I place as many switch-boards in the central office as are found necessary or desirable in order to properly answer the calls and connect and disconnect the subscribers lines. 0n each board I place for cach line which enters the office a switching device or devices adapted to make the necessary connections and disconnections of the line and to make the necessary connections and disconnections of the local-test system, which I shall hereinafter describe.

In the drawings I have shown spring-jack switches adapted to closed-circuit lines. Other forms of switches may be nsed which will practically accomplish the saine purpose. My testing system is also applicable to open-circuit lines, and in this case it is not necessary to have the switches adapted to remove a ground-connection from a line when the line is switched for conversation.

Figures l and ll of the drawings are front views of sections of two multiple switch-boards to which the same lines are connected. Fig. 2 shows a complete diagram ofthe boards with their connections and all the central-offline apparatus, circuits, and connections necessary to operate my test system.

In the drawings like parts and apparatus are indicated by the same letters of reference.

In Fig. 2, Ais asectional view ofthe switchboard shown in Fig. l, as indicated by line d e,

and A is a sectional view of the switch-board shown in Fig. 1b, as indicated by line c.

c I) represent rubber strips on which the metal parts of the springjack parts are mounted. These strips may be long enongh to receive any convenient number of springjaclr parts.

Z Z, die., are rectilinear holes through the fronts and at the edges of the strips adapted to receive the switch plugs. The contactsprings g g are mounted to the rear of and are parallel to the holes Z Z to which they belong, as shown. The contact-points h h, on which the contact-springs or spring-levers g y normally bear, pass through the rnbberstrips, as shown, and each has a connectingpiece, h', as shown. A contact-spring, g, and its contactpoint lz. form the main -line contactpoints of a switch. Toward the front of the switchholes and along,` their lower faces I place the contact-pieces i fi, as shown. These pieces eX- tend far enough to the front of the holes so that a test-plug or similar device may be applied to any of them by the operator at the board. In the rear of the contact-pieces i fi, and also along the lower faces of the switchholes, I place the contact-piecesff, as shown. These pieces are normally insulated from all other parts of their switches. The contactpiece and the contact-piecef of a switch form a pair of local contact-points, and the contactpiece i also acts as a test-plate or test-bolt of its line.

Fig. 3 shows a switch-plug,` adapted with the switches described above. n is the rubber handle and insulation of the plug. m is the mainline contact-piece ofthe plug, to which is connected the iiexible conductingcord. in is a local contact-piece and is insulated froin m. vi/'hen a plug is inserted into a switch-hole, the piece mpresses on theleverg and raises it from the contact-point h, and consequently connection is broken between gand 7L and is made between g and in. At the saine time the piece in ofthe plug bears on the pieces 'i and f of the switch and electrically connects them.

Each section of a rnbberstrip, with its springlever, contact-point, contact-pieces, and the hole, all arranged and operating as above, may be called a spring -jaclz switch, and the for use switches of a line on the different boards may be called a series of spring-jack switches. The rubber strips are placed one above the other, as shown. The lower edge of one strip therefore provides the upper edges ofthe holes in the strip which is below it. The holes may be of any convenient arrangement adapted to the shapes and arrangement of the parts used.

Two subscribers lines are sh own in the drawings. They are marked line No. 1 and line No. 2. s s are the spring-jack switches for line No. 1 on the two boards, and r rare the springjack switches of line No. 2 on the two boards. The circuits and connections are as follows for the main lines: Line No. l, for instance, after entering the office, passes first to spring-lever g of switch s', and thence, through contactpoint h and connecting-piece 71, of that switch and wire s, to spring-lever g of switch s, and thence, through contact-point h and connecting-piece 71, of that switch and wire s, to its calling-annunciator lw, and thence to ground. Line N o. 2, as would be every otherline of the exchange, is connected in a similar manner through its series of switches.

G represents the ground-connection.

E is an electric bell or other test-receiving instrument.

T is a test-plug with a flexible conductingcord,and t is a branch test-wire for switchboard A, and E is a test-receiving instrument. T is a test-plug with a flexible conductingcord, and t is a branch test-wire for switchboard A.

B is an electric battery for thelocal test-circuit of line No. l, and B is a battery for the local test-circuit of line No. 2.

The local test-circuits and connections are as follows: All the contact-piecesff of all of the switches of the system are connected together. Switches s, s', r, and r are thus shown as having their contact-pieces f f connected` together by the wire f and its branches f f, &c. All contact-pieces i i, Snc., of the switches of a given line are connected together. The contact-pieces i and i of switches s and s are shown as connected by Wire 8, and the contact-pieces i and t' of switchesrand rare shown as connected by wire 91.

The wire f and its branches may be called the common test-wire,77 and the wires s"aud its branches, rm and its branches, &c., may be called individual test-wires77 of their lines. The test-battery of a line is placed in a loop or wire which connects the common test-wire with the individual test-wire of the line. This Wire may be considered as a part of the individual test-wire, and the wires to the pieces 'L' i of its switches should not branch off between the battery and the common test-wire.

The branch testwire of a switch -board branches off from the common test-wire, as shown, and in it is placed the test-receiving instrument. It terminates in the test-plug T or T', with its flexible cord adapted to be brought at will into connection with any contact-piece i of its board. These branch wires :may terminate in or be connected to any other circuit from her test-plug through her testbell, thence th rough the common test-wire to the individual. test-wire of the line and the battery, and thence to the contact-piece 1'- thus forming a closed circuit in which is the bell and the battery. If, however, the line is switched at another board, the bell will not ring, because the battery is short-circuited by a circuit of very much smaller resistance through the contact-piece m of the switchplug which is used to switch the liuc and the circuits, as shown and described. The operator will thus know on testing whether or not the line is switched for use at another board.

I have only shown two switch-boards in use and two test-bells-one test-bell for each board. Other switch-boards and other test-bells might be added to the system and the connections of the lines and switches and test-circuits would be similar to the above, and such as will be evident to those skilled in the art.

I have not shown in detail the method of answering calls and making connections at the central ottice. Vell-known forms of apparatus and connections may be used for this purpose.

I claim as my invention and desire to secure by Letters Patent- 1. In a telephone-exchange system, two or more multiple switch-boards to which the same telephone-lines are connected, local testcircuits havingapair of contact-points or testbolts at the switches, one test-circuit for each line, each test-circuit containing a battery and connected to each board on each side of the battery, and said battery being normally open, and a switch-plug having insulated contacts crossing the test-bolts at the connected switches for automatically shunting the test-circuit around a tested switch through a line of less resistance when the main line is switched for conversation at another switch, in combination with a test-receiving instrument connected on one side to each test-circuit at one side of the battery, and a test-plug whereby the operator may at will connect the test-receiving instrument on its other side to any test-circuit at the other side of the battery, substantially as and for the purpose set forth.

2. In a telephoneexchange syste1n,the combination of two or more multiple switch-boards for telephone-lines with series of switches, one switch for each telephone-line, and one switch of each series being on each board, circuitclosers, one circuit-closer for each switch,each circuit-closer being closed automatically by the insertion of a plug in its switch, local test- IOO IIO

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circuits, each test-circuit containing a testbattery and two contact-pieces and connected on the two sides of its battery to the two contact-pieces, respectively, of each of its circuitclosers on the several boards, a test-receiving instrument at each board, and switch-testing devices whereby the operator at any board may at will connect her test-receiving instrunient into circuit with either of said test-circuits, the connection with said circuit being on the two sides of its test-battery, substantially as and for the purpose set forth.

3. In a telephone-line switch, the combination of the main-line contacts g and 7L, a pair of contactpoints which are closed on the insertion of a switch-plug and opened on its withdrawal,said contact-points being mounted on one of the inner faces of the plughole and insulated from the contacts g and It, and one of said contact-points being also a testplate for the line to which a test-plug may be applied, substantially as set forth.

4. A spring-jack switch containing within the plughole two main-line contact points or pieces which are normally in contact with each other, in combination with apair of test-bolts arranged within the plug-ho1e on one of the inner faces of the plug-hole and insulated 'from each other and from the mainline contact-pieces, and a switclrplug` having two parallel insulated contact-pieces, said plug being adapted, wheninserted into the switch, to dis connect the main-line contact-pieces from each other and connect one of them to one of the contact-pieces on the plug and to cross the two test-bolts through the other contactpiece of the plug, substantially as set forth.

5. In a telephone-exchange system, multiple switch-boards provided with series of switches, one switch for each telephoneline, and one switch for each series arranged on each board, local-circuit closers, one circuit-closer for each switch, and each comprising separate contacts, whereby it is closed automatically by the in sertion of a switch-plug into its switch, testplates arranged one for each switch, each testi plate being one of the contact-points of the circuit-closer of its switch, or connected thereto, local test-circuits, one for each line, each test-circuit containing a test-battery and connected on the two sides of its battery to the two contact-pieces, respectively, of each of its circuit-closers on the several boards, a test-receiving instrument at each board, and a plug for each test-receiving instrument, said plug beingconnectcd with a lexible conductingcord to one side of the test-receiving instrument and adapted at the will of the operator to be brought into connection with any of the test-plates at her board, and the test-receiving instruments being connected on their other side with said `local test-circuits with their batteries between the instruments and their test-plates, substantially as and for the purpose set forth.

6. In a telephone-exchange system, the combinationof'twoormoreswitch-boards,the main lines andniai n-line circuits between the boards, the test-circuits, one for each line, including all the boards, a battery in every test-circuit, a common test-wire connected with all the testcircuits, test devices connected with said common test-wire, and test-bolts at each switch included in the test-circuits, substantially as set forth.

7. In a telephone-exchange system, the combination of test-circuits, the test-bolts at each switch connected with the test-circuit, a testplug connected with a signaling` device and with all the test-circuits at one end and adapted to close a circuit through the signaling device when the line is not switched, and circuit-coa nections of comparatively low resistance between the test-circuits at one board with the test-bolts at the other boards, whereby the testcircuit at the tested board is short-circuited when the line is switched at another board.

8. In a telephone-exchange system, the con1- bination of the contact-pieces f f at the several switches, the common test-wire f and branches f2, which connect them, the contactpieces i at the several switches, electrical connections between all the pieces t in a given line, a battery in each test-circuit, and a test plug and signal, substantially as set forth.

MIL() G. KELLOG G.

Witnesses:

CALVIN DE WOLF, WALLACE L. DE WOLF.

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