USRE11387E - Multiple switchboard - Google Patents

Description

M. G. KELLOGG. MULTIPLE SWITCHBOARD.

2 Sheets-Sheet 2.

No. 11,387. Reissued Npv. 14, 1893.

Q MQW {yu/g www0 @AdM/@Magma UNITED STATES PATENT OEEICE.

MILo e. KELLOGG, 0E CHICAGO, ILLINOIS..l

M U LT'IPLE SWITCH BOARD.

SPECIFICATION forming part Vof Reissued Letters Patent No. 11,387, dated November 14, 1893. Original No. 388,052, dated August 2l, 1888. Application for reissue led January 8, 1891.- Scrial No. '377.180.

To all whom it may concern:

Be it known that I, MILOG. KELLOGG., of Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Multiple Switchboards for Telephone-lilxchanges,- of which the following is afull, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invent-ion relates to a telephone-exchange system in which the subscribers lines are metallic circuits; and it consists of apparatus for and a system of testing at any board of the exchange to determine whether any line is in use at another'board.

In the accompanying drawings, illustrating my invention: Figure 1 is a diagram illustrating the main-line switch-board apparatus and circuits. Fig. 2 shows a diagram of two operators cord systems for receiving and answering calls at two boards, switching and clearing out subscribers lines and for testing to determine whether a line is in use. Fig. 3 shows a diagram of the connections of the subscribers station apparatus. a modification of the main switch board and circuits.l y

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

In Fig. 1, A is a sectional view of one switchboard, and A is a sectional view of another switch-board to which the same lines are connected. I place as many' boards at the office as are found necessary or desirable in order to properlyanswer the calls and make the connections.

or other suitable switch for each line. Each spring-jack has a contact-spring, which normally` bears on an insulated contact-point and has another contact-piece insulated from the rest of the apparatus (except by line connections) and is adapted to receive a loopswitch plug, and when the plug is inserted to disconnect the spring from the contact-point (on which it normally rests) and connect the contact-pieces of thepplug with the contactspring and said contact piece of the switch, respectively.

In the drawings g, g represent the springs 5o of the different switches, h, 7L the contactpoints and j, j, the contact-pieces.

The plugs D, D, (shown in Fig. 2) when Fig. 4 showsA On each board is a spring-j ack v inserted operate the switches, as above described. v

The contact-pieces j, j should be so placed that a test-plug or other switch-testing device maybe readily connected with them.

a, 19,. represent the rubber strips on which the metal parts of the switches are mounted,

as shown.

fr', r', and s', s are the switches for two lines.

w is a calling-annunciator and s", 8'", and 3 are circuit wires or connections for one line, as shown.

Each subseribers circuit begins, say, at the central office and passes by a wire, which I will call wire Nala to the subscribers station apparatus, through the apparatus, and back to the central oiice by 'another wire, which l will call wire No lb. One of the wires-say wire No. 1"-is connected to all the contact-pieces above vmentioned of its switches al: the diierent boards. The other wire passes successively through the contactpoints formed by the spring-levers and their corresponding points of the switches on the dilerent boards, passing in each case to the spring iirst. It then passes toY the ground. If an annunciator is used to receive the calls of a line, it vis preferable to place it in the circuit of the line after it has passed through the contactpoints, as above, and before it passes to the ground. The lines are not connected to the ground at the subscribers station during conversation, but may be so connected at other times.

In Fig. 2 S, S, are operators cord systems for switching, answering, &c., subscribers lines.v Each system has pairs of double ilexible cords with double or loop'plugs adapted to tit into the switches and make the necessary connections. 'I'he two systems are intended to be used'at two boards.

.D D, &c., are the double plugs. A

Y Y are switches--one for each pair of cords.

t t are operators telephones. B B are calling generators or batteries an V V are clearing-out annunciators.

fm. m are the contact-pieces of the loopplugs, and n fn, are the rubber insulations of the plugs.

y y, a z,&c., are the contact-bolts of the IOO switches Y Y. Connections between them and various instruments are as shown.

ro o are ground strips orplates on which the switch plugs normally rest.

WVeights, as areusuahorother devices may be used to bring the plugs to normally rest on the ground plate. The cord should be of sucient length to reach any switch of the vboard at which they maybe placed, and all the apparatus should be conveniently mount ed and placed at the board at which it is to be used. The circuits are as shown.

T T are operators test systems-one for each board shown.. Each test-system contains a test-receiv`ing bell, a liexible cord, and a test-plug attached to the cord, and adapted at the will ofthe operator to be brought into electrical connection with any of the contact pieces jj, at the board where it is located. liis a test-battery. It is connectethon one side, as shown', to the test systems, and on the other side to the cord circuit of each pair of cords in the exchange.

In the subscribers outfit shown in Fig. 3, l is the telephone-switch, 2 is the calling-gen! crater, 3 is the signal receiving bell, and at is the subscribers telephone. The connections are substantially as shown.

In the modification of the main line switch board and circuits the lines are not normally grounded after passing through the switches, but are open to the ground at the central office.V The testing apparatus I have shown and described is applicable to both systems ot' main line circuits described and shown.

In the drawingsl have shown but one pair of cords and plugs in each operators system. Other pairs may be added, in ways evident to those. skilled in the art. For the test-receiving instrumentJ the operator might use a telephone 0r other suitable apparatus in place ot' the hell which is shown.

Whenan operator at any board desires to test a line to see whether it is in use at another board, she connects her test plug to the contact-pieces atl her board of the line to be tested, and if the'line is in use there will be a Acomplete circuitJ through the test bell and the battery, and the test-bell will respond, and she will know that the li-ne is already in use. The circuit can be traced as follows: From the test battery, through the test bell to the test plug,and thence through the contact-piece and the line to the switch cord, which is used in switching, and thence to the battery. It', however, the line is not switched for use, there will be no such complete circuit whe'n thetest' is made and the test bell will not respond. l y The general arrangement for testing herein described and shown is broadly claimed in an application for reissue of Patent No.v

382,477, tiled by me December 3, 1890, and the claimsherein are limited to the special or` ganizations not claimed in said application.

I claim as my invention and desire to secure by Letters Patentl. In a telephone exchange system, ametallic circuit-line normally grounded at the central office, a switch for said llne containl ing two contact-pieces to which the two sides switch, and when inserted to connect its two contact-pieces with the two contact-pieces of vthe switch, in combination with a testreceiving instrument connected on one side to one of the conductors of. said double cord and on the other side to a switch-testing device adapted to be brought into connection with a contact-piece of the line, and a battery in the circuit between the switch-testing device and the contact .piece of the plug connected therewith, substantially as set forth. y

2. In a telephone exchange system, metallic circuit lines, normally grounded at the central otice multiple switch-boards for 'said lines, switches for said lines, one switch on each board, each switch containing two contact-pieces, to which the two sides or branches of the line are respectively connected, and pairs of loop-plugs at each board, each plug being adapted to be inserted into any switch and when inserted to connect its two contacti pieces with the two contact-pieces of the switch, respectively, the two contact-pieces of one plug being connected with the contactpieces of its mate, respectively, by two conductors with liexible ends, in combination with test-receiving instruments, one at each board, each instrument being connected on one side to one of the conductors connecting each pair .ofcords and on its other side to a switch testing device adaptedV at the will of the operator to connect it with any line for testing,an`d a battery in the test-circuit thus established, substantially as set forth.

3. In atelephone-exchange system, metallic circuit lines, multiple switch-boards for said' lines, switches for said lines, one on each board for each line, each switch containing three contact-pieces, two of which are-normally in contact, and the third piece being insulated from the others, (except by the line connections) one branch of eachline passing successively through the pairs of contactpieces of its switches, which are normally connected,and from the last contact-piece to the ground, the other branch of the line be ing connected to said third contact-pieces of its switches on the different boards, in combination with loop-plugs, with two flexible conductors connected to the two branches of another line, said plugs being each adapted to be inserted into the switches at the boards EIO where they are located, and when one is inserted into a switch to disconnect the pair of contact-pieces of the switch, which are normally in contact, and connect the two contact pieces of the. plu g with the two contact pieces l of the switch which are then connected with a battery in` the test-circuit thus established,

substantially as set forth.

4. In a telephone exchange system, the combination with multiple switch boards, two 1ne.`

tallic circuit lines, normally grounded at the central oice, and switch devices on each board for switching any of said linestogether in closed metallic circuit for conversation. of a test connection or circuit at each board, circuit connections whereby said lines are connected with one side of the test connect-ion for each board when the lines are switched for conversation, the other side of said test connection being adapted to be brought at its board into contact with either of said lines,

and a test device and battery in the test circuit completed or established at any board.

5. In a telephone exchange system, the combination with multiple switch boards, two metallic circnitlines normally grounded at the central oiiice, and switch devices on each board for switching any twoof said lines together in closed metallic circuit for conversation, of an all metallic test. connection or wire for each board containing a test receiving instrument and battery, and circuit connections wherebyl said lines are connected with one side of the test connection for each board when the lines are switched for conversation, the other side of said test connection being adapted to be brought at its board into contact with eitherV of said lines for testing.

6. In a'telephone exchange system, the combination of multiple switch boards, two metallic circuit lines normally grounded at the central oliice, a switch for each line on each board, a test circuit or connection containing a test battery and test receiving instrument for each board, lineswitching devices and circuit connections whereby said lines'may at any board be disconnected from the ground and cou- 'nected together in metallic circuit for conversation and also connected with one side of the test circuit or connection of that board, and a test plug or device connected with the other side lof said-test connection and adapted t0 be brought for testinginto connection with either of said lines.

7. In ateleph'one exchange system, metallic circuit lines, multiple switch'boards for said lines, switches forv said lines, one switch on each board, each switch containing two contact-pieces, to which thetwo sides or branches of the line are respectively connected, and pairs of loop-plugs at each board, each plug being adapted to be inserted into-any switch, and when inserted to connect its two contactpieces with the two contact pieces of the switch, respectively, the two contact pieces of one plug being connected with the contact pieces of its mate, respectively, by two cnductors with flexible cords, in combination with a battery connectedon one side to one of the conductors connecting each pair of plugs, and test receiving instruments',one at each board, each instrument being connected ou one side to the other side of said battery and on its other side to a switch testing-device adapted at the will of the operator to connect it with any line fnr testing.

- In testimony whereof I have hereunto set my hand this 3d day of January, 1891.

. MIL() G. KELLOGG. Witnesses:

EDWARD C. DAVIDSON, M. J. KELLEY.

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