US592348A

US592348A - Milo g

Info

Publication number: US592348A
Authority: US
Publication date: 1897-10-26
Anticipated expiration: 1914-10-26

Description

(No, Model.)

M. G. KELLOGG.

MULTIPLE SWITGHBOARD Patented Oct 26,1897.

IINTTED STATES PATENT FFICE.

MILO G. KELLOGG, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE KELLOGG SIVITOIIBOARD AND SUPPLY COMPANY, OF SAME PLACE.

MULTIPLE SWITCHBOARD.

SPECIFICATION forming part of Letters Patent No. 592,348, dated October 26, 1897.

Application filed anuary 2, 1890- Z'o all whom it may concern:

Be it known that I, MILO G. KELLOGG, of Chicago, in the county of Cook and State of Illinois, temporarily residing at Stuttgart, in the Empire of Germany, have invented certain new and useful Improvements in Multiple Switchboards for Telephone-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.

My invention relates to a telephone-exchange system in which the lines are singlecircuit lines grounded at their outer ends; and it consists in a system of testing the lines to determine whether they are in use.

In the drawings illustrating my invention, Figures 1 and 1 represent sections of two multiple switchboards of the exchange .to which the same lines are connected. Fig. 2 shows a diagram of the boards with the mainline apparatus and connections necessary to illustrate my invention. Fig. 2 is a detail view of one of the line-annunciators. Fig. 3 shows a diagram of an operators cord system to be used in connection with the boards. Fig. a shows an operators test system to be used at the boards.

In Fig. 2, A is a sectional view of the switch board shown in Fig. 1, and A is a sectional view of the switchboard shown in Fig. 1", each as indicated by the line d c.

I place as many boards in the central office as are found necessary or desirable in order to properly operate the exchange. On each board is a spring-jack orothersuitable switch for each line. Each switch has a contactspring which normally connects with an insulated contact-piece and is adapted to receive a loop-plug and, when aplug is inserted, to disconnect the spring from the contactpiece and connect the two contact-pieces of the plug with the spring and said insulated contact-piece, respectively. The switch is also adapted to receive a single contact switchplug and, when a plug is inserted, to disconnect the spring from the contact-piece and connect the spring with the contact-piece of the plug. In the construction of the switches as shown and as will hereinafter be described I prefer to have a contact-point electrically Serial No. 335,698. (No model.)

connected with the contact-piece and on which the spring normally bears, as there is less chance of poor connect-ion when the spring bears on a point than when it bears on a surface adapted to be brought into connection with the plug-contacts.

In Fig. 2, g g represent the springs of the different switches, h h the contact-points on which the springs normally bear, and jj the contact-pieces of the switches connected with the points 71. h. Z Z are the SWltOlbllOlGS. a b are the rubber strips on which the metalparts of the switches are mounted, as shown, and through the fronts of which are the switchholesl l. The contact-piecesj j are so placed along one of the surfaces of the plug-holes as readily to form connection with one of the contact-pieces of the loop-plug. The holes Z Z are adapted to receive the switch-plugs, (shown in Fig. 3 and marked D D,) and when a plug is inserted into a switch it raises the spring 9 from the contact-point h, and the spring 9 and contact-piece of the plug are in contact. These holes are also adapted to receive the loop-plug shown in Fig. 4, and when a plug is inserted into a hole it raises the spring of the switch from the contactpoint It, and the spring g and the contactpiece j of the switch are in contact with the two contact-pieces of the plug, respectively.

to and o: are calling-annunciators, one for each of the lines shown. Each annunciator has a pairof contact-points normally (or when the annunciator does not indicate a call) in contact with eachother, but which are separated by the annunciator while it indicates a call. The two contact-points of a pair are marked 19 and g, respectively. One of them, q, is a spring-contact, which is pressed by the annunciator-drop when the drop falls away from its corresponding contact-point p. The contact-point p is represented as an anglepiece which passes over the spring (1 and is in contact with the spring when the spring is not actuated by the annunciator-drop.

The annunciator is shown in detail in Fig. 2 The line runs to an insulated bolt 0 at the top of the annunciator-plate 0, thence through the an nunciator-coil to the plate, and thence normally through spring g, which is in electrical contact with the plate, to the insulated angle-piece 19, against which spring q normally bears, and thence to earth.

Two lines are shown in the drawings, one marked line No. 1 and the other line N o. 2. These lines are ordinary single-circuit lines grounded at their outer ends and having at the subscribers stations any usual and appropriate subscribers station, apparatus. Each line passes successively through the pairs of contacts of its switches on the several boards, passing in each case to the spring first. It then passes through its line-annunciator and the pair of contact-points of the annunciator to the ground. The circuit of each line shown may thus be traced in Fig. 2.

In the operators cord system shown in Fig. 3, D D are the switch-plugs of a pair of cords. n n are the rubber insulations of the plugs, and m m are their contactpieces. These contact-pieces pass each to the bottom of its plug. and are adapted to rest normally, or

when the plug is not in use, on the metal piece 0, which then connects it with. the ground. Weights, as is usual, or similar devices may be used to bring the contact-pieces of the plugs into. contact with the piece 0 and secure a good connection. adapted to be inserted into any of the switches at their board,and when a plug is inserted it. operates theswitch, as above described.

The'plugs should be inserted so that the contact-piece m is in contact with the spring g. The connections. of the lines might have been reversed, so that the lines pass firstto the contact-piece j of each of their switches, and in that case the plugs should be inserted in such a position that their contact-pieces formconnection with the piecesj of the switches. Y is. the looping-in switch for the pair of cords shown. K is thecalling-key. R is a resistance-coil, and v is a clearing-out annunciator. t is the operators telephone, and B. is her call-. ing generator or battery. The circuits are substantially as shown.

The two contact-pieces of the-plu gs are connected by flexible conductors to the two le vers, respectively, of the looping-in switch. One of the pairs of contact-bolts of the switch is connected together through the clearingout annunciator and the other pair is connected through the operators telephone. The lever of the calling-key is connected to one of the cords, and the point of the key is grounded through the calling generator or battery. The resistance-coil is placed in the circuit of the other cord of the pair.

The operation of the system in connection with the switchboards will be apparent to those skilled in the art. It will readily be apparent that when a line is switched by the insertion of a plug into its switch the line is disconnected from its normal ground at the centraloffice and is connected into a circuit with thepair of cords and that the resistancecoil of the pair of cords is in itscircuit. Only onepair o1": cords. is shown, but the connection of such other pairs, with their accom- These plugs are panying apparatus as the operator may need, will be apparent to those skilled in the art. To each pair of cords, with its plugs, belong a looping-in switch, a resistance-coil, aclearing-out annunciator, and a calling-key. One telephone and one calling-generator will answer for her system of cords. The plugs should be inserted into the switches oi. the lines, so that the calling-key is connected to the circuit of the cords between the resistancecoil and the switch-plug inserted into the line whose bell it may be desired to ring. If desired, two calling-keys may be used for each pair of cords, one connected on each side of the resistance-coil.-

In the operators test system shown in Fig. 4, .T is a loop test-plug adapted to be inserted into any of the switches, and when inserted to operate them, as heretofore described. B is a test-battery, and S is a test receiving instrument. The battery and instrument are j connected in a loop which terminates in the 1 two contact-pieces of the plug. Each operator has one cord system and one test system, and they are conveniently mounted and arranged for her work.

The test receiving instrument and battery are so constructed and related to each other that when they are looped into the circuit 1 with any line and the circuit is not open at same pair of contact-points and does not have the resistance-coilin its circuit the instrument Will sound or respond, but when the circuit is open at any point or has the resistance-coil 1 connected as described in it the instrument will not sound or respond.

The operation of the test system is as follows: When an operator desires to test a line, she places her test-plug into the switch of the line and by so doing disconnects the pieces g 1 and j of the switch and connects them with the contact-pieces of the plug. If, then, the i line is not switched at any switch and its annunciator does not indicate a call, the instrument and battery are on a closed circuit with the line and the instrument will sound or respond, indicating that theline is free to be connected to. If, however, the line-annunciator' indicates a call, (and the line is not switched,) the circuit is open at the pair of annunciator contact-points and the instrument will not sound. If, again, the line is switched at any board when the test is made and the switch in which the test is made is in the cutoff portion of the line, or that portion which is between the switch used for switching and the office ground, the test-circuit is open at the. pair of contacts 9 71. of the switch used for switching and the test receiving instrument wil not sound. If, again, the line isswitched a switch which is between the one used and the subscribers station, the test-circuit has the resistance of the resistance-coil in circuit with the line and the instrument will not sound. When a test of a line is made and ithe test receiving instrument sounds or reat any board and the test-plug is inserted into sponds, the operator therefore knows that neither the line is switched for use at any board nor its annunctator indicates a call and that she may connect the line with another. When she makes the test and the instrument does not sound, she knows that either the line is switched for use at some board or its annunciator indicates a call, and she will not connect it with another line. By this system of switching and testing a subscribers line tests busy when it is switched and when his annunciator indicates a call. His line is reserved to himself as soon as he has sent in a call and will not be switched with another line before his operator has had time to answer his call to his confusion and annoyance. In this system, also, there are only two contacts for each line on each board instead of three or more,as in other systems with groundcircuit lines, and there is only one wire lead ing in and one leading out from each switch instead of three or more in other systems. There is also but one wire between any two boards for each line instead of two or more, as in other systems.

I claim as myinvention and desire to secure by Letters Patent- 1. In a telephone-exchange system, a telephone line normally passing successively through pairs of switch contact-points, one pair on each of several boards, each pair normally closed but open while the line is switched at their board, and through a pair of annunciator contact-points norm ally closed but open while the annunciator indicates a call, in combination with switching devices at each board to disconnect said pair of contact-points at the board and switch the line for conversation with a resistance coil switched into the circuit, and a loop test-plu g in the two contact-pieces of which terminate the two sides of a loop containing a test receiving instrument and battery, said loopplug being adapted to be inserted into a switch and when inserted to disconnect said pair of contact-points of the switch which are normally in contact and connect them with the two contact-pieces of the plug, said battery and instrument being so related and adj usted that the instrument sounds when looped into the closed circuit of the line without the resistance-coil, but does not sound when the resistance-coil is included in the circuit, substantially as set forth.

2. In a telephone-exchange system, a telephone-line grounded at its outer end and normally passing, successively, through pairs of switch contact-points, one pair on each of several boards, each pair normally closed but open while the line is switched at their board and through a pair of annunciator contactpoints normally closed but open while the annunciator indicates a call and thence to the ground, in combination with switching devices at each board to disconnect the pair of contact-points at the board and switch the line for conversation with a resistance-coil switched into the circuit, and a loop testplug in the two contact-pieces of which terininate the two sides of a loop containinga test receiving instrument and battery, said plug being adapted to be inserted into a switch and when inserted to disconnect said pair of contact-points of the switch which are normally in contact and connect them with the two contact-pieces of the plug, said instrument and battery being so related and adjusted that the instrument sounds when they are looped into the closedcircuit of thc line but does not sound when the resistancecoil is included in the circuit, substantially as set forth.

3. In a telephone-exchange system, a telephone-line normally on closed circuit and passing successively through pairs of switch contact-points, one pair on each of several boards, each pair normally closed but open while the line is switched at their board and through a pair of contact-points of the lineannunciator normally in contact but open while the annunciator indicates a call, in combination with switching devices at each board to disconnect the pair of contact-points at the board and switch the line for conversation with a resistance-coil then switched into the circuit, and a loop test-plug in the two contact-pieces of which terminate the two sides of a loop containing a test receiving instrument and battery, said plug being adapted to be inserted into the switches and when inserted into a switch to disconnect its said pair of contact-points and connect them with the two contact-pieces of the plug, said instrument and battery being so related and adjusted that the instrument sounds when they are looped into the simple closed circuit of the line but will not sound when the resistance-coil is included, substantially as set forth.

4. In a telephone-exchange system, a telephone-line grounded at its outer end and passing normally successively through pairs of switch contact-points, one pair on each of several boards, each pair normally closed but open while the line is switched at their board, and through a pair of contact-points of the line-annunciator normally in contact but open while the annunciator indicates a call, and thence to the ground, in combination with switching devices at each board to disconnect the pair of contact-points at the board and switch the line for conversation with a resistancecoil then included in the circuit, a loop test-plug in the two contact-pieces of which terminate the two sides of a loop which contains a test receiving instrument, said plug being adapted to be inserted into the switches and when inserted into a switch to disconnect its said pair of contact-points and connect them with the two contact-pieces of the plug, and battery in the test-circuit thereby established, said instrument and battery being so related and adjusted that the" instrument sounds when they are looped into the simple closed circuit of the line but will not sound when the resistancecoil is switched into circuit with the line, substantially as set forth.

5'. In a telephone-exchange system, 'a telephone-line normally on closed circuit and passing successively through pairs of switch contact-points, one pair on each of several boards, each pair normally closed but open while the line is switched at their board, and through a pair of contact-points of the lineannunciator normally in contact but open while the. annunciator indicates a call, in combination with switching devices at each board to disconnect the pair of contact-points at the board and switch the line for conversation with a resistance-coil then switched into circuit. with it, a loop test-plug in the two contact-pieces of which terminate the two sides of a loop which contains a test receiving instrument, said plug being adapted to be inserted into the switches and when inserted into a switch to disconnect its said pair of contact-points andi'connect them with the two contact-pieces of the plug, and battery in the test-circuit, thereby established, said instrument and battery being so related and adjusted that the instrument sounds when they are looped intolthe simple closed circuit of the line but will not sound when. the resistance-coil is switched into circuit with the line, substantially as set forth.

6. In a telephone-exchange system, a telephone-line normally on closed circuit and havin g in its circuitpairs of switch contact-points, one. pair on each of several boards, each pair normally closed but open while the line is switched for use at its board and having in its circuit apai'r of annunciator contact-points normally closed but open while the annunciator indicates a call, in combination with switching devices at each board to disconnect said pair of contact-points-atv the board and switch the line for conversation with a resistance-coil then switched into circuit with it, and loop test-plugs, one at each board, each plug having two contact-pieces in which terminate the two sides of a loop containing a test receiving instrument and battery and adapted to be inserted into the switch of the 5 line, at its board, and when inserted to disconnect said pair of contact-points which are normally in contact and connect them with the two contact-pieces of the plug, each instrument and its battery beingso related and adjusted that the instrument sounds when they are looped into the simple closed circuit, of the line; but will not sound when they and the resistance-coil are switched int-o circuit with the line, substantially as set forth.

Z. In a telephone-exchange, system, a telephone-line normally on closed circuit and 1 having in its circuit pairs of switch contactpoints, one pair oneach of several boards,

each pair normally closed but open while the line is switched for use at their board and having in its circuit a pair of contact-points of its annunciator, normally closed but open while the annunciator indicates a call, in combination with switching devices at each board to disconnect the pair of contact-points at the board and connect the-line for conversation with a resistance-coil then switched into circuit with it, and loop test-plugs, one at each board, each plug having two contactpieces in which terminate the two sides of a loop-which contains a test receiving instrument and adapted to be inserted into the switch of the line at its board and when inserted to disconnect the pair of contactpoints which are normally in contact and connect them with the two contact-pieces of the plug, and a battery in the circuit established on testing, each instrument and the battery being so related and adjusted that the instrument sounds when they are looped into the simple closed circuit of the line but will not sound when they and the resistancecoil are switched into circuit with the line, substantially as set forth.

8. In a telephone-exchange system, multiple switchboards,telephone-lines,switches for said lines, one switch on each of the boards for each line, each switch having a pair of contact-points normally in contact but open while a switch-plug is inserted, line-annunciators, one for each line, each annunciator having a pair of contact-points normally in contact but open while the annunciator indicates a call, each line passing successively through said pairs of switch contact-points of its switches and through its annunciator and the annunciator contact-points, in combination with pairs of switch-plugs atv each board, the contact-pieces of each pair being connected by flexible conductors containing a resistance-coil in their circuit, said plugs being adapted to be inserted into the switches at, their boards and when inserted into aswitch to disconnect the pair of contact-points of the switch and connect the line contact- ;point of the switch with the plug con-tactpiece, and loop test-plugs, one at each board, each plug having two contact-pieces in which terminate the two sides of a loop containing a test receiving instrument and battery and adapted to be inserted into any switch at its iboard and when inserted into a switch to disconnect the contact-points of the switch and connect them with the contact-pieces of the plug, each instrument and its battery being so related and adjusted that when they are looped into the simple closed circuit of t any line they will sound but will not sound iwhen they and one of said resistance-coils 2 are in circuit with the line, substantially as set forth. 7

9. In a telephone-exchange system, multilple switchboards, telephone-lines, each line L being normally on a closed circuit, switches for said lines, one switch on each of the boards for each line, each switch having a pair of contact-points normally in contact and open while a switch-plug is inserted into it, lineannunciators, one for each line, each annunciator having a pair of contact-points normally in contact but open while the annunciator indicates a call, each line passing normally successively through said pairs of contact-points of its switches on the several boards and through its annunciator and the contact-points of the annunciator, in combination with pairs of switch-plugs at each board, the contact-pieces of each pair being connected by a flexible conductor containing a resistance-coil in the circuit, said plugs being adapted to be inserted into the switches at their boards and when a plug is inserted into a switch to disconnect the pair of contact-points of the switch and connect the line contact-point of the switch with the plug contact-piece, and loop test-plugs, one at each board, each plug having two contact-pieces in which terminate the two sides of a loop containing a test receiving instrument and battery, and adapted to be inserted into any switch at its board and when inserted to disconnect the contact-points of the switch and connect them with the contact-pieces of the plug, each instrument and its battery being so related and adjusted that when they are looped into the simple closed circuit of any line the instrument will sound but will not sound when the instrument and battery are included in the circuit of the line and any of said resistance-coils, substantially as set forth. 7

10. In a telephone-exchange system, multiple switchboards, telephone-lines, each line being normally 011 closed circuit, switches for said lines, one switch on each of the boards for each line, each switch having a pair of contact-points normally in contact but open while a switclrplug is inserted into it, lineannunciators, one for each line, each annunciator having a pair of contact-points normally in contact but open while the annunciator indicates a call, each line passing normally successively through said pairs of contact-points of its switches on the several boards and through the annunciator and the contact-points of the annunciator, in combi nation with pairs of switch-plugs at each board, the contact-pieces of each pair being connected by flexible conductors which contain a resistance-coil in their circuit, said plugs being adapted to be inserted into the switches and when a plug is inserted into a switch to disconnect said pair of contactpoints and connect the line contact-point with the contact-piece of the switch, and loop testplugs, one at each board, each plug having two contact-pieces in which terminate the two sides of a loop which contains a test receiving instrument, and adapted to be inserted into any switch at its board and when inserted to disconnect the contact-points of the switch and connect them with the contact-pieces of the plug, and a battery in any test-circuit established on testing, each instrument and battery being so related and adjusted that when they are looped into the simple closed circuit of any line the instrument will sound but will not sound when they are included in a circuit which contains the line and either of said resistance-coils, substantially as set forth.

In witness whereof I hereunto subscribe my name this 13th day of December, 1889.

MILO G. KELLOG G.

\Vitn esses EMIL ,ABENHEIM, MARGARETHA RIEHL.