US2250922A - Signaling system - Google Patents

Description

July 29, '1941. i F. E. WELD SIGNALING SYSTEM Filed May 5, 1939 I5 Sheets-Sheet l m E, Q wil@ \N 0 NI .II Y Ow wlmk'@ 1% C, e8. mi D JM mmh n Nw l b mw L EN QS A @QN .ww mm, W

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WLness July 29, 1941. F. E. WELD SIGNAMNG SYSTEM Filed May 5, 1939 3 Sheets-Sheet 2 vuil# ..0 IN m mw@ @L T@ lmvl@ @n Y @MQ l July 29, 1941. F. E. WELD y SIGNALING SYSTEM Filed May 5, 1939 5 Sheets--Shee'l 5 .wn W V@ W @LN T ww nmnml@ Gm X Mw ,WL m QUIIIM Patented July 29, 1941 Gamewell Company, Mass., a corporation of ltlassachusettsv Application May 5, 1939i, Serial No. 271,925

14 Claims.

The present invention relates to signaling systems, and more particularly to systems of the general type disclosed in the Bridges Patent No. 2,201,712, granted May 21, 1940.

The Bridges patent discloses a multiple circuit repeater system particularly useful for re alarm service. The system not only affords full noninterfering operation, but has reliable protective facilities for automatically maintaining all normal circuits in operative condition after the occurrence of a break in any circuit. In particular, one feature of the Bridges system is that the protective equipment involves the use of only a single timing relay for the whole system, and normal signaling operation is in no way dependent on the timing relay.

The principal object of the present invention is to provide improvements in the Bridges system with the particular View of maintaining the ability of the system to formulate, transmit and repeat signals, even from a circuit in which a break may exist. In the best form of the invention yet devised a faulty circuit, instead of being isolated from the rest of the system, is automatically conditioned for Signaling through an emergency conductor, preferably ground, while the capacity of the system for non-interference is substantially maintained.

Other features of the invention consist of certain novel circuit arrangements hereinafter described and particularly defined in the claims.

In the accompanying drawings Fig. 1 is a diagram of the preferred system in normal inactive condition; Fig. 2 is a diagram similar to Fig. 1 but illustrating the operation of the system during transmission of a signal; and Fig. 3 is a diagram illustrating the emergency conditioning of a faulty circuit.

General description The invention is herein described as embodied in a repeater type fire alarm system having a number of signaling circuits. For simplicity, only two circuits are shown in the drawings, although the invention is applicable to a system having an number of circuits. The signaling circuits are indicated as box circuits Cl and C2. Those parts of the box circuits which are local to the central station are indicated in double lines in the drawings, and each is connected at terminals, designated Line and Line, to the outlying lines. The lines external to the central station include a number of boxes in series, designated N, of the non-interfering and succession type,

Newton Upper Falls,

and capable of signaling through ground as will hereinafter be described.

Each box circuit includes a line battery 20 and a normally energized main line relay. The two main line relays are indicated at M1 and M2. Associated with each b'ox circuit are a repeater relay (R1, R2) and an automatic grounding relay (G1, G2). Each relay has a number of contacts which are shown in the drawings directly under the corresponding relay winding. Each main relay has seven contacts numbered from lato 7, of which contacts I, 4 and 6 are movable. Contacts 3, 4 and 5 correspond to the main relay'contacts of the Bridges patent above referred to, the movable contact 4 being normally closed on contact 3 and adapted to closeon contact` when the relay Mis deenergized. Contacts l, 2 are normally open and are adapted to close when the relay is deenergized, to control the operation of the grounding relay as will hereinafter be described. Contacts 6 and 'l control the operation of a trouble bell. Y

Each repeater relay hasten contacts, numbered from I lll to lill, of which contacts 103, IM, |08 and IUS are movable. Contacts Ill, |01 and |08 correspond to the repeater relay contacts of the Bridges patent. Contacts Ill! to m5 are for controlling the operation of the system under abnormal conditions, while contacts |69 and H0 are included in the trouble bell circuit.

Each grounding relay has twelve contacts, numbered from 2U! to 2l2, the operation of which will be hereinafter described.

The box circuit Clin normal condition is traced as follows: Starting with the positive terminal of the battery 20, the circuit includes the winding of the main line relay M1, a wire 22 leading to the terminal designated Line, through the series boxes N of the outlying line to the terminal designated Line, a wire 24, contacts lll?, |26 of the repeater relay R1, a wire 26, contacts 2H), 29 of the grounding relay G1, and finally a wire 28 back to the negative side of the battery 20.

The movable contact |08 of the'repeater relay is connected to a resistor 30, which in turn is connected to the line 22' by a wire 32. As inthe above-mentioned Bridges patent, when the repeater relay is energized, contacts'lll', |06 are closed and contacts |05, |01 are opened, thereby opening the box circuit and establishing a shunt energizing circuit for the main line relay M1 through the resistor 30.

The movable contact A of the main line relay is connected by a wire 34 with the movable repeater relay contacts |03 and |04, which are electrically connected together. The fixed contact |05 on which |04 is normally closed, is connected by a wire 36 with a repeater bus RB. The main line relay contact 5 on which contact 4 closes when the relay M is deenergized, is connected to the positive side of a local battery 31. The local battery serves for all central station connections of the several circuits and its terminal-s are simply designated by plus and minus signs in circles, the actual connections to the terminals being omitted to avoid complieating the diagram. It will be observed that when the main relay is deenergized, the repeater relay being at the same time deenergized, the positive side of the loc-al battery is connected to the repeater bus through contacts 5, 4, wire 34, contacts |04, |05 and Wire 36. These latter connections, as well as the repeater bus RB, constitute a repeater circuit which is shown in heavy lines.

Upon energization, the repeater relay opens the normally closed contacts |04, |05, closes the normally open contacts |0I, |03 and opens the normally closed contacts |0|, |02. Contact |0| is connected by a Wire 38 with one side of the repeater relay Winding R', the other side of which is connected to the negative terminal of the local battery. Contact |0| is also connected by a wire 40 Ywith contact 3 -of the main line relay.

The grounding relay G1 is adapted, under abnormal conditions caused by a break in the box cir-cuit, to connect the terminals Line and Line together and to ground the negative terminal of the box circuit battery 20. One side of the grounding relay is connectedto the negative terminal of 'the local battery and the other side is connected by a wireV 42 with contact A lamp 44 in parallel to the relay G1 serves -to indicate when the relay is energized. Movable contact 203, which is Vadapted to close on 20| when the relay G1 is energized, is connected to the positive terminal of the local battery. Closure of contact 203 on 20| opens contacts 20|, 202, the latter being connected by a wire 4 6 with the fixed contact 204. The movable contact 205 which is adapted to close on 204 when the relay G1 is energized, is connected by a Wire 48 with the xed contact |02 of the repeater relay. Movable contact 206 connects by a wire 50 with the repeater relay contacts |03 and |04, and the iixed contact 201 on which 206 is normally closed, is directly connected to the wire 36 which connects with the repeater bus.

The normally closed contacts 209, 2|0 are, as previously described, included in the box circuit. When the relay G1 is energized, contacts 209, 2 l0 open and 209 closes on 208, the latter being connected to ground as indicated at 52, thus establishing a direct connection between the negative terminal of the line battery 20 and ground. The fixed contact 2| is directly connected .to the Line terminal and the movable contact 2|2 is connected to the wire 32 which connects with the Line terminal, so that when contacts 2l I, 2| 2 close, due to energization of the grounding relay, the two terminals of the outlying line are connected together,

Contact 202 is connected by a wire 54 with the movable contact of the main line relay. "f -Contact 2 is connected by a wire 56 with a bus designated as a restore bus X. A trouble bell busTBB is connected by a lead 58 through contacts |09, ||0, a Wire 60 and contacts 1, 6 to the positive terminal of the local battery. The bus includes a bell 62 connected to the negative terminal of the local battery so that the circuit for the bell is closed when contacts |09, I0 and 1, 6 are closed.

The second circuit C2 and all other box circuits which may be included in the system are identical with the circuit C1 above described, and are connected to the several busses in the same manner.

A single delayed closure timing relay T has its winding connected between the negative terminal of the local battery and the repeater bus RB. The contacts 64 of the timing relay are normally open and are adapted' to close only if the timing relay remains energized continuously for greater than a predetermined time, which is adjusted to be longer than the longest time of box circuit opening of any normal signaling operation. When the contacts 64 close, a connection is established between the positive terminal of the local battery and the restore bus X through a lead 65.

The system may be provided with suitable signal manifesting devices to operate in the usual manner, illustrated diagrammatically in Fig. 1 as a gong A and a register B connected between the repeater bus RB and the negative terminal of the local battery.

The various operations of the system under different conditions will now be described.

System inactive When the system is in normal condition, all boxes being inactive, each box circuit forms a closed loop and the several main line relays are continuously energized, thus holding their movable contacts attracted. The repeater relays and the grounding relays are deenergized. 'Ihis condition of the system is shown in Fig. 1.

Box signaling over normal system During a code signaling operation by an active box in one of the box circuits, say circuit C', the circuit is successively opened and closed by the action of the code wheel. Upon the rst opening of the circuit by the code wheel, the main line relay M is deenergized and its movable contacts I, 4 and 6 retract. The closure of contacts 6, 1 simply operates the trouble bell, and the closure of contacts 2 is of no importance at this time. The closure of Contact 5, 4 energizes the repeater relay R2 of the box circuit C2 as can be seen by following the circuit shown in heavy lines, from the positive terminal of the local battery through contacts 5, 4 of main line relay M, wire 34, contacts |04, |05 of repeater relay R, wire 35, repeater bus RB, thence through wire 36 of circuit C2, contacts |05, |04 of repeater relay R2 (also contacts 201, 206 o-f grounding relay G2 and wire 50), Wire 34, contacts 4, 3 of main line relay M2, and wires 40 and 33 through the repeater relay R2 to the negative terminal of the local battery. The repeater relay R2 of circuit C2, being thus energized, attracts its contacts, thereby opening box circuit C2 at |06, |01 and establishing a shunt circuit for the main line relay through resistor 30 and contacts |08, |06. The repeater relay R1 of circuit C1, however, remains deenergized since the main line relay contacts 3, 4 are now open.

The result of opening the box circuit C1 by the formulation of a signal in the circuit, is that the inactive circuit C2 and, in fact, any other inactive box circuits of the system, are likewise opened and the main line relays of the inactive circuits are maintained energized. This condition of the system is shown in Fig. 2.

Upon closure of circuit C1 by the normal action of the code wheel of the active box, its main line relay is again energized, the contacts are attracted and the connection between the positive battery terminal and the repeater bus is broken at contacts 4, 5, thereby deenergizing the repeater relay R2 of the circuit C2 and restoring its contacts to normal. The restoration of the repeater relay contacts of circuit C2 also opens the shunt circuit through the resistor 30, and at the same time closes the box circuit. The entire system is thus restored to the condition of Fig. 1.

Subsequent opening and closing of the circuit C1, due to formulation of a code signal by an active box therein, result in a repetition of the operations above described. All inactive box circuits therefore open and close in unison with the first box circuit to gain control of the system. The boxes are of the non-interfering and succession type, and consequently the entire system is completely free of the possibility of interference between boxes. The particular box construction forms no part of the present invention, since various types of non-interfering boxes may be employed, such boxes usually operating on the principle that a box is unable to formulate a signal if it looks into an open line when its own contacts are closed.

During a code signaling operation, the time relay T and the manifesting devices A and B, being connected to the repeater box RB, are energized on each opening of any box circuit. For any signaling impulse, however, the relay T is not continuously energized for a sufficient time to cause closure of its contacts 64, and the time relay does not enter into any normal signaling operation.

As thus far described, the system operates similarly to the system of the Bridges patent. It will be noted that the repeater relay contacts to correspond to the lockout relay contacts of the Bridges system, but are here combined with the repeater relay instead of being operated by a separate relay. As will be shown presently, these contacts, in 'combination with the contacts of the grounding relay, operate under abnormal conditions in a fashion similar to the lockout relay contacts of the Bridges system. Under normal signaling conditions, however, the only repeater relay contacts which are effective to perform any function are the contacts |05, |01 and |08. The lockout contacts |0| Vto |05 of the repeater relay, although they may be attracted and retracted during a normal signaling operation, perform no function. Contact |02 is in series with the normally open grounding relay contacts 204 and 205, while contacts |04 and |05 are in parallel with the normally closed contacts 206 and 201. Thus, so long as the grounding relay remains deenergized, any operation of contacts |0| to i 05 is unimportant.

Operation ofpotective devices The occurrence of a break in any box circuit does not disable the system, but permits all except the faulty box circuit to be restored to normal, and also converts the faulty circuit for emergency signaling through ground. This operation is described as follows:

Upon a breakin circuit C', for example, its main line relay M', is deenergized andy the repeater relays of all inactive circuits -are energized in the same manner as if theY circuit were opened by an active box. The system then assumes the condition of Fig. 2. After a predetermined time, however, the timing relay allows its contacts 64 to close, thereby connecting the positive terminal of the local battery with the restore bus X through the lead 66. The grounding lEnergization of the. grounding relay occurs 'only for circuit C'. The grounding relay G2 of circuit C2 is not energized because the main line relay contacts I, 2 of that circuit are open.

When the grounding relay Gr'l is energized, its movable contacts 203, 205, 206, 209 and 2|2 are attracted and, as previously described, the negative side of the battery 20 is connected to ground through contacts 209, 209, and the positive and negative terminals of the line areconnected together through contacts 2| l, 2|2. Thus, the box circuit C' now consists of two outlying lines, each running to the break.

When the grounding relay G is energized, a holding Ycircuit isfestablished from the positive side of the local battery through contacts 203, 20| and at the same time contacts 202, 20| are opened. y

Energization of the grounding relay G results in energization of the repeater relay R ofthe faulty box circuit. Bearing in mind that the positive potential of the local battery is applied to contact 202 through the circuit previously traced, a circuit may now be continued from contact 202 through lead 06, contacts 204, 205, wire 48, contacts |02, |0| of the repeater relay R', and wire 30 through the repeater relay winding to the negative local battery terminal. Contacts 204, 205 might be omitted and the wire 40 might be connected direct to contact |02, so that relays R and G' would be simultaneously energized, except that it is desirable to insure that G' shall energize before R'; if R' should pick up its contacts first, the main line relay might be energized through the shunt resistor 30 before G' could open the circuit at 209, 2|0. Energization of the repeater relay opens contacts |02, I0 but a holding circuit for the repeater relay is established from the positive battery terminal, through contacts 5, 4 of the main line relay M', wire 34 and contacts |03, I 0| of the repeater relay. As a result of the energization of the repeater relay, contacts |00, |00 are closed and contacts |06, |01 are opened, but this is of no importance since the box circuit loop is already open at contacts 209. 2|0.

Since both the repeater relay R' and the grounding relay G' are now energized, the heavy At the same time the timing relay T is deenergized and its contacts are allowed to open.

Another effect of the energization of the repeater relay R is to open the trouble bell circuit at contacts |09, ||0.

The conditionof the system following the operation above described is'illustrated in Fig. 3. It

will be observed that the lockout contacts |l to |05 of the repeater relay R' perform the same general function as the lockout relay contacts of vthe Bridges system, namely, that of isolating the main line relay contacts of the faulty circuit from -th'e repeater bus, so that the faulty circuit can neither affect, nor be affected by the repeater connection. 'Ihis action occurs only because the -grounding relay 'G' is also energized, so that the lconnection 36 is broken both at contacts 201, 206 .and |05, |04. Ihe correlation of grounding relay and repeater relay contacts thus makes it possible to combine the repeating, lockout and grounding functions into two relays. In spite of the fact that the system is adapted for automatic emergency conditioning, the number of relays is thus held to three for each circuit.

It is to be noted that the isolation of the faulty circuit C from the repeater'bus occurs only during continued deenergization of the main line relay M, since the holding circuit for R is carried through contacts 4, 5. As will be shown presently, when the relay M becomes energized, as at the start of a ground signaling operation, the faulty circuit is no longer isolated from the system.

Boa: signaling over the system conditioned as shoumfn Fig. 3

When t-he system is conditioned as in Fig. 3, dueto` operation of the grounding relay on a faulty box circuit, the normal box circuit C2 and any other normal box circuits of the system stand ready to originate and transmit signals, and

cuits, and this will b'e done by describing, first,

the effect on a normal circuit Vof a'sgnal originating in the faulty circuit, and, second, the effect on the faulty -circuit of a signal originating in a normal circuit.

Assume first that with the system as shown in Fig. 3, a box in the faulty circuit C starts to formulate a signal. 'I'he boxes are of a type to transmit emergency signals through ground, for which purpose several types of boxes are available. The preferred type of box is the so-called threefold box 'described in the Beach Reissue Patent 20,449, which includes means fortesting the line and `establishing an emergency ground signaling connection on the -second round, if the line is found to be open. Whatever type of box is employed, a connection is first established to ground prior to the signal formulating operation. A closed circuit may now be traced from ground through wire 52, contacts 208, 209 of the grounding relay G', wire 28, battery V20, mainline relay M', Wire 22, to terminal Line, wire 32 and contacts 2|2, 2|| of relay G to the terminal Line," then from one or the other of the line terminals to the box, and finally to ground at the box. The main line relay M is then energized and its contacts are attracted, thereby breaking the holding circuit for the repeater relay R' at the contacts 4, 5. On subsequent opening and closing of the ground signaling circuit through the action of the code wheel, the main line relay is successively deenergized and reenergized in exactly the same manner as if the signal were being transmitted over a normally closed loop. The repeater relay R1, having been deenergized by the breaking of its holding circuit, remains deenergized during the entire signaling operation. Therefore, upon each deenergization of the main line relay, due to opening of the ground signaling circuit by the action of the code wheel, the connection between the positive terminal of the local battery and the repeater bus RB is established through contacts 5, 4, wire 34, contacts |04, |05, and connection 36, just as in the case of normal signaling. Accordingly, signals originating from any box in the faulty circuit are repeated over all normal box circuits in the lsystem and thus interference with any active box in circuit C1 by a box in any other circuit is prevented.

At the conclusion of the signal the ground connection at the box is broken and the main line relay is deenergized. It is now necessary to reenergize the repeater relay R1 in order to permit all normal box circuits to be restored to normal condition. This is accomplished by the action of the timing relay operating through the restore bus X. In other words, the timingrelay and the repeater relays of' the several circuits go through the same operations a's they did' immediately following the detection of the break in the faulty box circuit. The grounding relay G1 of the faulty -circuit remains -energized throughout, because of the holding circuit established at contacts 20|, 203.

Assume now that with the system in the condition of Fig. 3, a box in the normal circuit C2 starts to formulate a signal. In this case there is no effect on the faulty circuit C1 because the connection for circuit C1 which leads from the repeater bus RB terminates on the open contacts 201 of the grounding relay G1 and |05 of the repeater relay R1. Hence, while a signal originating in the faulty circuit can repeat into all normal circuits, the reverse is not true and a signal originating in a normal circuit cannot repeat into the faulty circuit. Interference will, therefore, occur if a box in the faulty circuit is pulled while a box in a normal circuit is transmitting a signal. This contingency is remote and even if it does occur, it will ultimately result in circuit C1 taking control of the system, even though there may be some initial jumbling of the signals. This follows from the general proposition that a box or circuit having good non-interference characteristics will lose control to a box or circuit of poorer non-interference characteristics; that this proposition holds in this specific case may be seen by considering that in the normal operation of the code 'wheels a time must come when the main line relay M1 is deenergized and the main line relay M2 is energized. At such a time the repeater circuit to the repeater relay R2 is closed and the energization of the repeater R2 under suchY circumstances results in opening the box circuit C2 and thus cuts the active box of circuit C2 out of further participation. It will be noted that circuit C2 is unable to prevent circuit C1 from gaining control even at a time when relay M2 is deenergized and relay `M1 is energized, because the consequent energization of repeater relay R1 has no'eifect on circuit C1. The result is therefore that 'the box in the faulty 'circuit takes control at some time in the round. One round may be jumbled, but a clear signal is thereafter transmitted by the active box in the faulty circuit. After such box has completed its signal the system is restored to the condition of Fig. 3 through the operation of the timing relay, and thereafter the waiting box in the -normal circuit, if it is of the succession type, will formulate and transmit its own signal.

The foregoing method of operation is considered the preferred method, in spite of the possibility of jumbled signals under unusual circumstances. If desired, however, the faulty circuit Ymay be eifectually isolated from the remainder of the system by providing a manual switch B3 in each lead 36. After a box circuit has been found faulty, the switch 63 may be opened manually, thus making it impossible for the faulty circuit to affect or to be affected by any of the other circuits. It is, however, considered preferable to allow the faulty circuit to participate in the operation of the system as a whole, even at the risk of occasional jumbling, than to isolate the faulty circuit from the rest of the system.

Restoration of circuit after repair After the break in the faulty box circuit has been repaired, the circuit isl restored to its normal loop condition manually, by momentarily opening a switch 68 in series with the contact 203 of the grounding relay G. This opens the holding circuit and deenergizes the grounding relay. Movement of contact 209 to 210 and of 2|| to 212 closes the circuit of the main line relay M through the shunt resistor 3i), it being understood that contacts |06, |08 are now closed and contacts |06, 101 are open, due to energization of the repeater relay. Consequently, the main line relay is energized through the shunt resistor 30 and its contacts are attracted. The attraction of the main relay contacts breaks the holding circuit for the repeater relay at 4, 5. The repeater relay then becomes deenergized, and the circuit is restored to the normal condition shown in Fig. 1.

It will be noted that on opening the manual switch 68, contacts 206, 201 of the grounding relay will close before contacts 5, 4 of the main line relay open. A connection is then momentarily established from the positive terminal of the local battery through contacts 5, 4, wire 34, wire 50, contacts 206, 201 and wire 36 to the repeater bus. This momentary connection will tend to cause the repeater relays of normal circuits to be energized and give a stroke on the system. To prevent this, a switch 'l0 is preferably included in the lead 63 and is adapted to be opened simultaneously with the manual switch 68.

Conclusion -From the foregoing description it will be seen that the system is in general similar to that of the Bridges patent, in that perfect non-interference between normal circuits is obtained.

Furthermore, the reliability of the system is enhanced by the provision for automatic emergency conditioning of a faulty circuit, instead of rendering such circuit inoperative. This result is attained without serious loss of non-interfering characteristics, since as previously described, the only possibility of interference arises when a box in the faulty circuit starts to operate during a signal formulation by a box in a normal circuit.

As in the Bridges system, the protective devices have the important advantage of being dependent on a single timing relay which in no way enters into any signaling operation. Failure of the timing relay or its connections can result only in a lossV of protective function and cannot deprive the signaling circuits, so long as they are in normal condition, of their ability to signal and repeatin normal fashion. l

Although the invention has been illustrated and described as embodied in a fire alarm system, it is to be understood that the invention is not thus limited, but may be applied to signaling systems for other purposes. Furthermore, the invention is not to be considered as limited to the particular embodiment shown and described but may be modied within the scope of the claims.

Having thus described the invention, I claim:

l. A signaling system having in combination a plurality of normally closed signaling circuits each having a normally energized main line relay, repeater means for the several circuits, a grounding relay for each signaling circuit to condition the circuit for emergency ground signaling, timing means acting upon deenergization of a main line relay for a predetermined time to Operate the grounding relay of the corresponding circuit, and lockout means operated by the timing means to isolate said circuit from the repeater means during continued deenergization of the main line relay. Y

2. A signaling system having in combination a plurality of normally closed signaling circuits each having a normally energized main line relay, repeater means for the several circuits, a grounding relay for each signaling circuit to condition the circuit for emergency ground signaling, timing means acting upon deenergization of a main line relay for a predetermined time to operatethe grounding relay of the corresponding circuit, a lockout device for each circuit, and connections between the timing means and the lockout devices to isolate an abnormal circuit from the repeater means during continued deenergization of the main line relay.

3. A signaling system having in combination a plurality of normally closed signaling circuits each having a normally energized main line relay, repeater means for the several circuits, a grounding relay for each signaling circuit to condition the circuit for emergency ground signaling, a single timing relay for the several circuits operable upon deenergization of any main relay for a predetermined time, a lockout device for each circuit, and connections between the timing relay, the grounding relays and the lockout devices to energize the grounding relay of an abnormal circuit and also to isolate the abnormal circuit from the repeater means during continued deenergization of the main line relay.

4,'A'signaling system having in combination a plurality of normally closed signaling circuits each having a normally energized main line relay, a repeater relay for each circuit, a repeater bus connecting the main line relays and repeater relays of the several circuits, a grounding relay for each circuit to condition the circuit for emergency ground signaling, timing means acting upon deenergization of a main line relay for a predetermined time to operate the grounding relay of the corresponding circuit, and lockout means operated by the timing means to isolate vsaid circuit fromthe repeater bus during continued deenergization of the main line relay.

"5. A signaling system having in combination bus connecting the main line relays and repeater Arelays of the several circuits, a grounding relay foreach circuit to condition the circuit for emergency ground signaling, a 'single timing relay for the several circuits operable upon deenergization of any main line relay for a predetermined time, a` lockout device for each circuit, and connectionscontiolled by the time relay to operate' the grounding relay and also, during continued deenergization of the main line relay, to isolate the abnormal circuit from the repeater bus.

v`6. rA signaling system having in combination a plurality of normally closed signaling circuits each having a normally energized main line relay, a repeater relay and a groundingrelay for each signaling circuit, each grounding relay having provision for converting its circuit for emergency ground signaling, a repeater circuit, timing means operating upon de-energization of a main line relay for a predetermined time for operating the grounding relay of its circuit, while leaving the other circuits in normal condition, and lockout means for isolating a faulty signaling circuit from the repeater circuit.

7. A signaling system having in combination a plurality of normally closed signaling circuits each having a normally energized main line relay, a repeater relay and a grounding relay for each signaling circuit, each grounding relay having provision for converting its circuit for emergency ground signaling, a repeater circuit, a single timing device for the several circuits, connections between the timing device and the grounding relays to operate the grounding relay of any circuit for which the main line relay remains de-energized for a predetermined time, and lockout means for isolating a faulty signaling circuit from the repeater circuit.

8. A signaling system having in combination a plurality of normally closed signaling circuits each having a normally energized main line relay, a repeater relay and a grounding relay for each signaling circuit, each grounding relay having provision for converting its circuit for emergency ground signaling, a repeater circuit, the main line relays having contacts connecting With the repeater circuits, lockout means for opening the connections between the several main line relay contacts and the repeater circuit, and timing means operated upon deenergization of a main line relay for a predetermined time for operating the grounding relay and lockout means of the corresponding signaling circuit.

9. A signaling system having in combination a plurality of normally closed signaling circuits each having a normally energized main line relay, a repeater relay for each signaling circuit having contacts to open its signaling circuit, a repeater bus, each main line relay having a contact connected with its corresponding repeater relay and a contact connected With the repeater bus, lockout means for opening the connection between the main line relay contact and the repeater bus, time actuated means, additional main line relay contacts, and connections from the time actuated means through the additional main line relay contacts to operate the lockout means for any circuit for which the main line relay remains open for a predetermined time,

10. A signaling system having in combination a plurality of normallyclosed signaling circuits each having a normally en'ergizedmainV line relay, repeater devices controlled by the signaling circuits, a grounding device for each circuit operable to condition an open signaling Ycircuit for emergency ground signaling, a time 'relay having contacts to *operate only after an abnormal signaling circuit'remainsopen for a predetermined time, lockout means for each circuit, and connections including the time relay contacts to'oper-ate the grounding device of Yan abnormal circuit, said connections having provision for operating the lockout means of the abnormal circuit to render the abnormal circuit ineiective to control the repeater devices during continued deenergization of the mainline relay of the abnormal circuit.

11. A signaling system having in combination a plurality of normally closed signaling circuits each having a normally energized main line relay, repeater devices controlled by the signaling circuits, a grounding device for each circuit operableto condition an open signaling circuit for emergency ground signaling, a time relay having contacts to operate only after an abnormal signaling circuit remains open for a predetermined time, lockout means for each circuit, connections including the time rel-ay contacts to operate the grounding device of an abnormal circuit, said connections having provision for operating the lockout means of the abnormalcircuit to render the abnormal circuit ineffective to control the repeater devices during continued deenergization of the main line relay of the abnormal circuit, means for establishing a holding circuit for the grounding device, and means under the control of the main line relay for establishing a holding circuit for the lockout means of the abnormal circuit.

12; A signaling system having in combination a plurality of normally closed signaling circuits each having a normally energized main line relay and a repeater relay, repeater connections forl actuating the repeater relays of inactive Vbox circuits, a grounding relay and lockoutV means for each circuit, -a timing relay having contacts actuated only by the deenergization of the` main line relay of an abnormal signaling circuit for aA predetermined time, connections including the time relay' contactsto operate the grounding relay and the lockout means of the abnormal circuit, the lockout means having provision for isolating. the abnormal circuit from the repeater connections only during continued deenergization of the main line relay of the abnormal circuit.

13. A signaling system having in'combination a plurality of normally closed signaling circuits each having a normally energized main linerelay 'and normally deenergized vrepeater and grounding relays, the grounding relays being operable When energized to convert their corresponding circuits for'emergency ground signaling, repeater connections for actuating the repeaterrel'ays of inactive signaling circuits,`lockout contacts'for each repeater relay to isolate the corresponding signaling circuit from the repeater connections wheiiltlie repeater relay is energized, atiming relay having 'contacts actuated upon `deenergiza'tionofl amain line relay of 'an abnormal circuit fora predetermined time, con-V nec'tionsY including the Vtime relay. contacts "for energizing 'the"grounding and repeater 'relays o f the abnormal' circuit, Yand means for holding the repeater' relay o'f the abnormal. circuitv energized only during continued deenergization oi the corresponding main line relay.

14. A signaling system having in combination a plurality of normally closed signaling circuits each having a normally energized main line relay and normally rie-energized repeater and grounding relays, the grounding relays being operable when energized to convert their corresponding circuits for emergency ground signaling, a repeater circuit, each main line relay having a contact connected with the repeater circuit, lockout contacts for each repeater relay to open the said connection of said main line relay contact with the repeater circuit when the repeater relay is energized, a time relay having contacts actuated Yupon de-energization of a main line relay of an abnormal circuit for a predetermined time, connections including the time relay contacts for energizing the grounding and repeater relays of the abnormal circuit, and means for holding kthe repeater relay of the alonormal circuit energized only during continued cle-energization of the corresponding main line relay.

FOSTER E. WELD.

CERTIFICATE OF CORRECTION. Ptent No; 2,250,922. July 29, 19in.

FOSTER E. WELD.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page l, first column, line )46, for the word "an" read' --any-; page 2, firsxtl column, line 5b., for "--Line" read -"+Line"-; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case Vin the Patent Office.

Signed and sealed this 114th day of October, A. D. 1914.1.

Henry Van Arsdale, (Seal) I Acting Commissioner of Patents.

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