US1686492A - Call-box trouble detector - Google Patents

Description

Oct. 2; 1928. 1,686,492 w G. w. JANSON CALL BOX TROUBLE DETECTOR Filed Sept. 26, 1925 Patented Get. 2, 1928.

teeagg GEORGE W. JANSON, OF NUTLEY,

new Ja ar; Assrsnon 1"0 rnn vtrnsrnnixi Union TELEGEAIH COMPANY, onnnwyonrz, n. A oonrona'r'ron or new "roan.

CALL-Box rno'onnn nnrncron.

Application filed September as, 1925; Serial No. 58,912.

This invention relates to vmessenger call circuits which include a number of callbo'xes in a loop circuit extending from a'central office and particularly to means for testing the call boxes to determine whether the equipment is in proper operativecondit-ion.

When a signal or call is call box, the code wheels in circuit and ground the line a number-of times corresponding to the call number of the particular box. it is essential that the device for grounding the line in each box shall be I tested periodically in order to ensure proper operation at all times. this invention is to providemeans at the central station for testing the operation of the boxes and for detecting any that may be defective. Y In the following description I shall refer to the accompanying drawings, in Which Figure '1' is a' diagram of the circuits of a messenger call system; Fig. 2 is a diagrammatic illustration of a testing equipment or trouble detector; and Fig. 3 is a detail View of the jacks: for connectingthe trouble detector with the call circuit.

Referring first to the messenger call circuits, the loop circuit or line L, L containing the subscribers call boxes B, B B etc., is connected at the central station CS at one end through the jack J, relay R and resist ance T to a source of current supply E. The other end of the loop circuit'is connected at the central station through the jack J relay R conductor 10,- contacts 1 and 4: of switch S to ground. The contacts or relays R and R, are'connected respectively to switches S and S in such manner that, by changing the position of the switch levers, either the front or the back contacts of the relays may be used to operate the local register D and the buzzer Z. The triple pole switch S is arranged to remove the ground G and substitute current source E when necessary to overcome a fault in the line. Thisswitch also changes the connections of the register and buzzer circuits. The pilot relay PR is placed in the groundco'nnection of the signal lamp SL and thereby'controlsthe buzzer Z. 1 lVhen the line is' in normal condition, current flows from the current source E through the resistance T, relay R, jack J and the line containing he call boxes B, B B5, etc.,' returning through jack'J relay R contact points 1 and 4 ofswitch' S toground at G.

sent in from'any the box break'the.

v 1, lhe main purpose or The arinatures of relaysR and R arethus held against their front contacts, thereby keeping the local buzzer and register circuits open. When any call box such as B is operated,the break or signatwheel W opens the line the number of times required to produce the signal of that. particular box. Each break causes the armatures of both relays R and-1%, to fall against their-aback contacts, thus closing the circuits of the local signal lamp SL, the pilot relay PR, the buzzerZ and the register D. Currentnow flows from current source E through the armature and back contact of relay R, contactsti and 3 of switch S, resistance T and register D to ground at G thus causing the register to record the signal or box number on. the tape. Simultaneously current flows from thecurrent source E through the armature and back contact of relay R signal lamp SL, contacts and the pilot relay PR to ground at G' This. causes the signal lamp SL to glow and the pilot relay PR to close the local circuit .con-

taining thebuzzer Z. 1

Each signal box is provided with two break wheels W and W1, the'former' opening and closing the circuit as the spring tongue 25 moves across t-he' gap between ad ]acent teeth on the wheel WV; and the other toothed wheel W applying'a' ground con-; nection through. the tongue t aft ing of the circuit by the first. Wheel. The teeth of the 'two'wheels are staggered so that the ground applied by the wheel W and tongue t, is maintained for a time equal to that during which'the wheel XV had opened the circuit. lt'will be seen, therefore, that the relay It, will be deprived of current by the grounding at the tonguet and thus al.- low its armature toremain on the back coner the. open} tact duringthe'transmission of each digit of any signal, dueQto-tie fact as above explained,that a call box opens and thereafter."

jun

both closes and grounds the line simultaneouslytiereby shunting out the portion otthe line containing the relay R When the.

signal has been completed, however,the line 1S again'placed in'its normal closed cor'idi:

tion, so that the relay R again attracts'its armature against 1ts front contactas shown g f .-r-.

Let 'us. now assume that a break-occurs in the line at some point Q. RelaysR and R, will then be deprived of current, thus allowing their armatures to fall against their back contacts and close the buzzer and register circuits. The signal lamp will glow and the register and buzzer will operate continuous'ly until the trouble hasbeen temporarily overcome. This may be done by changing the position of switch S from the left to the right. This changes the local circuit so that the register is connected to the front contacts of both relays R and'R and at the same time applies the current source to the end of the line which was formerly grounded at G. Now when any call box such-as B is operated, the break wheel applies a ground to line L and causes current to flow in that particular portion of the line and through the relay R The armature of relay R is then drawn against its front contact,causing current to flow from the gener ator or source E, through the front contact and armature of the relay R switch S points 8 and 8 of switch S, and the register D, 'thuscausing the register'to record the signal on the tape. As either relay will now operate the local circuit it will be seen that the operationot a call box on the other side of the break will also repeat the signal into the register. 7

Now let us suppose that instead of breaking, the line had become accidentally grounded at the point Q. So long as the switch S remained in its left hand p osition,

that portion of the line containing the call boxes B B and the relay R 'would be deprived .of current, thus causing the armature of relay R tofall against its back contact and close the local signal lamp and buzzer circuits. .Buzzer Z will then buzz continuously and signallamp SL will remain lighted until the trouble has been temporarily overcome. This may be done by changing the position of the switch S from the left to the right and throwing switches S and S downward. The changing of these switches applies the current source to both ends of the line and at the same time changes the local circuit connections so that the -front contacts of therelays R and R are disconnected, while their back contacts Each portion of the main line circuit and the relay includedtherein operate independently. of the other, each relay responding only to signals sent from call boxes included in the portion of the line between that relay and the ground. Now when any call box is operated, that portion of. the circuit is broken a number of times corresponding to the signal number of that box and the signal is repeated into the local circuit containing the register. It will be noted that the register D is controlled by the contacts of both relays R and R and that the buzzer and signal only to such calls as are sent from call boxes included in that, portion of line between that. relay and the break or ground. The operation. of the portion of theline L is the same as explained above for a break at Q and the operation of the portion of the line .L isthe same as explained I, in the last paragraph. If the break had occurred on the other side of the ground, the switch S would occupy the upward position and the switch S would occupy the lower position. As soon as any trouble is discovered. the switches should be thrown'in such positions as to temporarily overcome that trouble, but as soon as the trouble has been cleared the switches should again be placed inithe'ir normal positions. 1

In order that the system shall be reliable i devices of the boxes shall be in working order. I havedevised a testing apparatus or equlpment whlch'may be connected wltha call circuit at anytime and may'iemain in. the circuit until the s gnals irom all oifthe boxes have been recorded at least once on the test tape. 7 It may be necessary to have some of the boxes operated p'urposelyfor this test in case no calls are received. from them during the time allotted for the test.

The trouble detector or call box testing equipment is illustrated diagrammatically in Fig. 2, and comprises a double pen register or recorder M controlled by relays or electro-responsive devices K and K This testing equipment is connected by flexible conductors with plugs P and P so that it may be readily connected to the call circuit by inserting the plugs in the jacks J and J as indicated in Fig. 3. It will'be observed that the coil 12 of'relay K and the coil 14 of relay K are in the. circuit of the outgoing line L of the call circuit loop while the coil 13 of relay K and coil 15 of relay 14 and 15 of relay assist in attracting its armature while the coils '12 and 13 of relayK oppose or neutralize each other. Hence the armature of relay K is normally attracted while thev armature of relay -K is normally retracted against its back stop. Accordingly, if a box having its tongue properly grounded is operated, both relays K and K will operate. The relay K will release its armature each time the tongue armature each time the grounding tongue 25,

touches the code, wheel W thereby shortcircuiting one of the windings on the relay K This closes a circuit from local current source E, through magnet 24, armature of relay K, and magnet 24: of the recorder, thereby causing the pen P to make a record on the tape 26. Hence in case of a properly grounded box, both pens P and P of the recorder will record the signal.

On the other hand, if the grounding tongue t, of the operated box hasbecome ungrounded, the opening of the circuit by the line tongue t deenergizes the relay K and releases its armature, the same as for a grounded box, but the relay K does not attract its armature andhence is not operated because no ground is applied by the tongue 25, and the currents which flow through its windings oppose and neutralize each other. p

Now suppose a short circuit should occur between the line conductors and thus by shunting out a portion of the call boxes prevent them from interrupting the flow of current through relays K and K Relay K, would remain energized when any of these boxes were operated and hence pen P,

would make no record. The operation of the boxes would however, by applying grounds, cause relay K, to respond to the signal and operate pen P It is apparent, therefore, that the pen P of the recorder will register signals from the line tongues 25 of the call boxes and the pen P, will register signals from the grounding tongues t, of the call boxes. Comparison of the records of pens P and 1? will indicate the accuracy of the tongues t 1 tuated by. said devlces for respectlvely conand t V The system would be operative if one of the coils, as 15, were omitted from relay K but in that case the plugs P and P, must always be inserted in thejacks J- and J as shown, but by winding the relay with GEORGE W. JANSON.

two 0011514 and 15 as shown, it is immaterial in which orderthe plugs are inserted inthe jacks.

I claim V 1. In combination with a messenger signaling system having signal call boxes, each being provided with two break wheels hav ing their teeth arranged in staggered relation, one of which. is connected through'a contacting brush in the line and the other cooperating with a grounded brush, whereby upon the operation of a box'the line is first momentarily opened and then momentarily grounded for each signal impulse of the code signal, of a testing equipment for determin ing whether the call boxes are in normalv operative condition, comprising an electroresponsive which magnetically assist each other, and

device having two windings an electro-responsive device having two windings which magnetically oppose and neutralize each other, one winding of each device being connected in the outgoing lead of said system and the other windings of said devices being connected in the returnlead of said system, and indicating elements controlled respectively by said devices.

2. In combination with a messenger si' naling system having signal call boxes, eac i being provided with two break wheels having their teeth arranged in staggered relation, one of which is connected through a contacting brush in the line and the other cooperating with a grounded brush, where by upon the operation of a box the line is first momentarily opened and then momentarily grounded for each signal impulse of the code signal, of a testing equipment for determining whether the call boxes are in normal operative condition, comprising an electro-responsive device having two wind ings which magnetically assist, each other,

and-an electro-responsive device having two windings which magnetically oppose and neutralize each other, one winding of each device being connected in the outgoing lead of said system and the other windings of said devices being connected in the return lead of said system, a source of current, a pair of recording elements and means acnecting said recording elements to said ture.

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