US2128578A - Signaling system - Google Patents

Description

Aug. 30, 1938. (F. R. BRIDGES SIGNALING SYSTEM Filed Dec. 24, 1955 2 Sheets-Sheet 2 l t H Z/i gi IJ QI v ,fizz erzior jarzi'fifiriges fliljs.

Patented Aug. 30, 1938 UlTED STATES PATENT OFFEQE 2,128,578 SIGNALING SYSTEM Frank R. Bridges, Needham, Mass,

The Gamewell Company,

assignor to Newton Upper Falls,

7 Claims.

This invention relates to signaling systems and more particularly to fire alarm and similar systems, which, as is well known, require provisions for reliable operation even under extremely adverse conditions as, for example, broken, grounded, or short circuited lines. Such provisions include in most cases the use of an emergency conductor. which is under certain conditions supplied with current impulses derived from the source normally supplying the signaling circuit with current. The present invention also utilizes a separate conductor, usually the ground, for emergency signaling, but provides improvements which render the operation of signaling systems of this type especially secure and certain.

The principal object of my invention is to provide a comparatively simple, rugged and therefore reliable, durable and inexpensive signal transmitting station or alarm box which is nevertheless adapted to perform the functions of more complicated devices for signaling under abnormal conditions through an emergency conductor, especially in circuits according to my Patent No. 2,056,709 of October 6, 1936, although it is understood that the new apparatus will provide these beneficial and novel functions in other installations.

Other objects and aspects of my invention will be apparent from the following description, by way of example, of a specific embodiment of the invention. This description refers to drawings, in which:

Fig. 1 represents a connection diagram of a signaling circuit including a sender according to the present invention;

Fig. 2 a side elevation of the contact and noninterference magnet portion of an alarm box incorporating my invention;

Fig. 3 is a schematical side elevation of the contacts of Fig. 2, showing the contact side by side instead of behind each other;

Fig. 4 is a detail View ofthe contact control mechanism shown in Figs. 2 and 3;

Fig. 5 a schematical representation of the spatial contact arrangement according to- Fig. 2; and

Fig. 6 a schematical representation of a modified contact control arrangement.

Referring to Fig. l, L denotes a signal line or loop leading to station terminals I and 2 and containing a number of signal transmitters, herein referred to as alarm boxes R, R, R which normally keep the signal loop closed and their ground connections open. Busses DC supply direct current of suitable voltage derived from any 'in the line.

convenient source, and leads 3 and 4 of the direct I current circuit D connect terminals I and 2 to these busses. Lead 3 contains an inductance ill intermediate terminal I and its direct current bus, and a signal recorder X is inserted in lead l between terminal 2 and the other direct current bus. Although the signal recorders are herein indicated as being of the tape imprinting type, it is understood that any signal manifesting device may be used instead as, for example, acoustic means or relays controlling separate signal manifesting or repeater circuits. A battery B, in the nature of a so-called floating reserve power supply, may be connected across leads 3 and 4.

Busses AC supply alternating current, preferably from the public utility line, to the primary I I of a transformer T. One terminal I l of the transformer secondary I2 is grounded, whereas the other terminal I5 leads to conductor 7, which is part of an alternating current circuit A including lead Sconnected to terminal I, a capacitance 2I, an inductance 23, recorders Z and Y, an inductance 24, a capacitance 22 and lead 6 connecting to terminal 2. Inductances 23 and 24, in series with condensers 2| and 22, are provided for the purpose of compensating the phase displacing efiect of the capacitances, in order to decrease as far as possible the impedance of the alternating current circuit.

The direct current derived from busses DC continuously supplies the signal loop L, so long as the latter is not interrupted by the code signal sending means of an alarm box, or by a break Condensers 2| and 23 prevent direct current from entering circuit A, whereas circuit D is protected from alternating current by choke coil In which is so dimensioned that its inductance presents an alternating current resistance of a magnitude excluding for practical purposes the alternating current of A. It will be obvious to any one skilled in the art, that inductance it passes substantially only direct current and that capacitances 2| and 22 pass substantially only alternating current, so that the loop L may carry superposed direct current and alternating current, whereas alternating current is excluded fromcircuit D and direct current from circuit A.

The signal transmitters R, R and R according to my invention have a normally closed shunting switch 10 which opens when the box. is pulled and. remains open so long as the box movement is operative, namely, so long as the double code wheel rotates. Arrangements of this type are well known in the art and for example shown .at d of Fig. 1 of Patent No. 553,838 to F. W. Cole. 555

The double code wheel 99 comprises two identical toothed portions on a common shaft I99 and is adapted to actuate two sets of switch levers 99 and 91, 98 and 99, respectively. Switch springs 99 and 91, and 98 and 99, respectively, are mounted on blocks of insulating material which electrically separate the switch levers but permit their joint operation by the code wheel, which upon rotating lifts and drops levers 91 and 99. In parallel with the shunting switch are spring contacts 96 and 91, connected to the signaling lines leading to terminals I and 2, respectively. Spring contacts 9I and 92 are connected to the terminals of a non-interference magnet I99, operative substantially only with direct current, and also to another pair of spring contacts 93 and 94, respectively, which cooperate with contacts 98 and 99, respectively. Switch levers 98 and 99, herein referred to as grounding contacts, are joined to ground through conductor 95. Under normal, inoperative conditions, the followers of levers 91 and 99 rest on cams 69 of the code wheel, which keep them in elevated position, thereby connecting levers 99 and 91 with contacts 9I and 92, respectively, whereas levers 98 and 99 are lifted from contacts 93 and 99. Pin 99 is associated with the armature of the noninterference magnet I99, for example as shown at 259 of Fig. 2, and permits free movement of levers 96 and 9?, if the non-interference magnet was energized during the initial signaling period of the box, notwithstanding a subsequent deenergization due to the opening of the signaling circuit at 9I and 92 or a subsequently pulled box. A locking arrangement accomplishing this result is, for example, described in Patent No. 1,244,587 to F. W. Cole for Successive non-interference box, dated October 30, 1917. If no current is flowing in the circuitdue to previous pulling of another box or to some accident, and non-interference magnet I99 is therefore de-energized upon the opening of I9, the pin moves underneath lever 91 and prevents its dropping and therefore the opening of the circuit at 9! and 92. Therefore, if box R is pulled with the circuit in good condition, as shown in Fig. l, the circuit remains closed over 99, 9I, I99, 92, and Si; I9 is opened, magnet I99 remains energized, pin 59 is out of the way, and the circuit is opened and closed at 9I and 92 when the follower of 9'5 drops in the interdental spaces of its code wheel, thereby initiating code signals. Shortly after contacts 9I, 96 and 92, 91, respectively, open, contacts 93, 98 and 94, 99, respectively, close, and establish a ground connection. The ground connection at 98 and 99 is again interrupted shortly before contact is reestablished at 9! and 92. When box R is sending, and the line is interrupted, as, for example, due to a break in the line as indicated at c, or due to another box already operating, pin 59 prevents levers 96 and 9'I from dropping and interrupting the circuit at M and 92, whereas levers 99 and 99 are independent of the non-interference magnet and establish ground connections at 99 and 99 every time the follower of 99 passes over the teeth of code wheel 99. The above-described subject matter will be found in my above mentioned Patent No. 2,956,799. i

Although this is not absolutely necessary, a switch with contacts I98, I99 may be provided between ground and conductor 95. This grounding switch is preferably operated together with the above described shunting switch l9, so that the alarm box is only grounded during operation of the box. This grounding switch has principally the function of an auxiliary gap preventing break down for example in case of an accidental connection of the signaling circuit with a power line.

The above described arrangement with two code wheels on a common shaft, although capable of satisfactory operation, may under circumstances introduce the difficulty of necessitating exact alignment of the cams which, if not operating their respective switches with the proper time relation may cause unsatisfactory operation. Hence, an arrangement providing the same function, but having only one code wheel, is preferable for practical purposes. An arrangement of this type is shown in Figs. 2, 3, 4, and 5.

As will be seen from Figs. 2 and 3, the arrangement of switches, magnet and line connections is exactly as in Fig. 1. Instead of having separate code wheels, contact groups 9i, 92, 99, 91 and 93, 94, 98, 99 have separate followers M9 and 2H, respectively, pivoted at H2 and moving the contact springs by means of insulator tips 259, 2I9. One of the followers, for example 2I9, is directly operated by a code wheel 299, as shown in Fig. 4. From follower 2 I9 extends a rod 69 across to follower 2II engaging it in a recess thereof, so that the two followers and the two contact groups necessarily move concomitantly. As above described with reference to Fig. 1, contacts 93, 99 and 94, 99 respectively close, and establish connection to ground shortly after contacts 9|, 99 and 92, 9'5 respectively are opened. Pin 59 cooperates in this instance with follower 2 which is prevented from dropping if 99 is moved in front of surface 25I of follower 2H. Contacts SI, 99, 92, 91 are then prevented from opening, exactly as above explained with whereas the operation of contacts 99, 99, 98, 99 is not affected. It will now be evident without further explanation, that this arrangement operates as described in connection with Fig. 1.

Under normal conditions of the signaling circuit the new system operates as follows: If the line is wholly normal and none of the boxes is operated or pulled, no alternating current flows in any part of the circuit since only one terminal of secondary I2 is connected thereto. Direct current flows in circuits D and L and is excluded from circuit A by condensers 2i and 22 as hereinbefore described. Record-er X is normally energized, whereas recorders Y and Z are deenergized and, upon operation of a box, signals are received at X, recorders Y and Z remaining inoperative. The non-interference arrangement of the box operates exactly as in a non-grounded system. However, boxes of the type according to the present invention keep the signaling circuit closed, but establish ground, and signal over ground each time when the non-interference magnets are deenergized upon a box being pulled, so that the signals of two simultaneously sending boxes are received correctly. For example, if box R is pulled first and box R somewhat later, the direct current signals of R" are received at X, whereas two alternating current circuits are established by box R. through ground and two branches of the signal loop, and corresponding signals are received at Y and Z. Box R signals over Y and Z while box R operates, whereas upon R stopping and releasing the direct current circuit, box R assumes control of the direct current circuit and its remaining signal impulses are also received at X.

In the case of a broken circuit, as indicated at c reference to Fig. l,

of Fig. 1, the direct current is interrupted, recorder X drops its: armature and becomes incapacitated, andsubstantially'no current flows in the system.

Assuming now an accidentally grounded signal loop as indicated at jg in Fig. 1, the direct current recorder or relay X remains energized, since the direct current circuit is not interrupted, but alternating current cicuits including ground 9 and the respective adjacent branches of the signal loop are now established in addition, so that recorders Y and Z are also energized and. their armatures attracted, indicating the faulty condition of the circuit. Since the direct current circuit is normal, correct signals are received at X from allboxes just as if ground g-were not present.

If a short circuit'exists across a signal box, for example, around box R" as indicated at min Fig. 1, this box is not able to signal over the direct current circuit since it is by-passed with respect thereto, but its signals are correctly received at recorders Y and Z, since upon becoming deenergized, the boxes drop the armatures of their direct current responsive non-interference magnets and signal through ground as above de scribed.

If both boxes-R and R", for example, are simultaneously pulled, both transmit understandable signals, box R over recorder X and box R over the alternating current recorders.

A short circuit across the entire signaling loop, as indicated at n of Fig. 1, influences the circuit as follows: Any one of the short circuited boxes is able to send signals over ground, which signals are received at X and/or Y. However, under this condition, two or more simultaneously pulled boxes produce mixed signals since the noninterference mechanisms of all short circuited boxes are incapacitated upon being deprived of their energizing direct current.

In circuits utilizing a transformer secondary i2 in series with the signaling loop, and having a grounded intermediate terminal (as shown in Fig. 2 of application Serial No. 620,683), my new alarm box functions in similar manner.

Instead of mechanically locking (as with stop- 59) the normal signaling contacts 9!, 92, 96, 91 in closed position upon deenergization of the noninterference magnet, a similar effect can be obtained electrically in a manner now to be described by way of example with reference to Fig. 6. In this figure, there are again four contact pairs 9l-96, 92-9l, 93-98 and 94-439. However, contact pairs 9|, 92 and 93, 94, which are in different switch units in Figs. 1 to 5, are now electrically connected and mounted on contact springs 224 and 2l3, respectively. A single code wheel 390 with follower 3 l operates both contact units by means of insulating actuator M and likewise insulating connecter 3|6. It will be noted that contacts 9499 and 9398 are normally open and contacts 92-9'l and 9l96 normally closed, establishing exactly the same circuit connections as the embodiments shown in Figs. 1 to 5. In addition, two shunting switches 3M and 392 are provided, having contacts 324, 391, M3 and 396 connected to contacts 224, 97, M3 and 95, respectively. Contact pairs 324391 and 3l3 39fi are normally retained open by means of pin 359 which is actuated by the non-interference magnet I99. The actuating mechanism of pin 359 may correspond exactly to that of pin 59 of Figs. 1 to 5 and is therefore not again shown in Fig. 6. If the armature is attracted as shown in Fig. 2, pin 350 is in the position shown in full 3 lines in Fig. 5, and keeps switches 3M and 392 open. If themagnet I00 becomes deenergized anditsarmature drops, pin 350 moves to the position shown in dotted lines in Fig. 6, and spring contacts 324-391 and 3 l3-396 close.

' It will now be evident that this arrangement functions like the one previously described. Namely, during normal operation, contact pairs 9398 and 99-99 close, and contact pairs 92 9'i and 9l-99 open every time when follower 399 drops into an interdental space of code wheel 999. If, however, the dropping armature of the noninterierence magnet has retracted pin 359 from contacts 396 and 391, switches 39! and 392 close, shunting-contacts 9l--91 and 94-98, respectively, thereby preventing the opening of the normal signaling circuit at these points. Otherwise the function of this embodiment of my invention is exactly as described with reference to Figs. 1 to 5.

It should be understood that the present disclosure is for the purpose of illustration only and that this invention includes all modifications and equivalents which 'fall within the scope of the appended claims;

I claim:

1-. A signal transmitter comprising two terminals, an auxiliary signaling connection, normally closed and normally open switching means connected in succession intermediate said auxiliary connection and each terminal respectively, signal initiating means for rhythmically opening and: closing said first switching means and closing and opening respectively said second switching means, said second switching means being closed subsequently to the opening of said first switching means and opened prior to the closing of said first switching means, switch control means, and means responsive to the amount of current flowing therethrough for actuating said control means, said actuating means being connected to said terminals in series with said normally closed switching means, and said control means maintaining said normally closed swtiching means in effectively closed position so long as the current in said actuating means remains within a predetermined range.

2. A signal transmitter comprising two terminals, an auxiliary signaling connection, normally closed and normally open switching means connected in succession intermediate said connection and each terminal respectively, signal initiating means for rhythmically opening and closing said first switching means and in the same rhythm closing and opening respectively said second switching means, said second switching means being closed subsequently to the opening of said first switching means and opened prior to the closing of said first switching means, switch control means, and means responsive to the amount of current flowing therethrough for actuating said control means, said actuating means being connected to said terminals in series with said normally closed switching means, and said control means maintaining said normally closed switching means in effectively closed position so long as the current fiow in said actuating means is substantially zero.

3. A signal transmitter comprising two terminals, an auxiliary signaling connection, normally closed and normally open switching means, conductors for connecting a normally closed and a normally open switching means in series intermediate said connection and each terminal respectively, signal initiating means for rhythmically opening and closing said first switching means and in the same rhythm closing and opening said second switching means, a non-interference magnet connected across the conductors intermediate the first and second switching means associated with each terminal respectively, and means controlled by said magnet and upon deenergization of the magnet retaining said first switching means in closed position during operation of said second switching means.

i. A signal transmitter comprising two terminals, an auxiliary signaling connection, normally closed switching means and non-interference means in series across said terminals, a normally open switching means between said normally closed switching means and said connection, and signal initiating means for rhythmically opening and closing said first switching means and in the same rhythm closing and opening said second switching means, said non-interference means retaining said normally closed switching means in closed position when deenergized.

5. A signal transmitter comprising two terminals, an auxiliary signaling connection, normally closed and normally open switching means connected in succession intermediate said connection and each terminal respectively, signal initiating means for rhythmically opening and closing said first switching means and in the same rhythm closing and opening respectively said second switching means, said second switching means being closed subsequently to the opening of said first switching means and opened prior to the closing of said first switching means, normally open shunting contacts in parallel with said first switching means, current responsive actuating means connected between said terminals in series with said normally closed switching means and means controlled by said actuating means for closing said shunting contacts as long as the current in said actuating means remains within a predetermined range.

6. A signal transmitter comprising two terminals, an auxiliary signaling connection, normally closed switching means and normally energized non-interference means connected in series across said terminals, a normally open switching means between a point of said series connection and said auxiliary connection, signal initiating means, actuating means intermediate said initiating means and said normally closed switching means for rhythmically opening and closing said normally closed switching means in response to said signal initiating means, a second actuating means intermediate said first actuating means and said normally open switching means for closing and opening said second switching means in the same rhythm, said noninterference means when deenergized arresting said second actuating means for retaining said normally closed switching means in closed position.

7. A signal transmitter comprising two terminals, an auxiliary signaling connection, normally closed switching means having contacts connected between said terminals, normally open switching means connected between said auxiliary connection and said terminals, signal initiating means for rhythmically opening and closing said first switching means and closing and opening respectively said second switching means, said second switching means being closed subsequently to the opening of said first switching means, and opened prior to the closing of said first switching means, means for controlling the effectiveness of said first switching means, and means responsive to the amount of current fiowing therethrough for actuating said control means and connected to said terminals in series with said normally closed switching means, said control means maintaining a current path across said contacts so long as the current in said actuating means remains within a predetermined range.

FRANK R. BRIDGES.

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