US2164324A - Electric signaling, supervising, and recording system - Google Patents

Description

y 4, 1939- J. R. HARRINGTON 2,164,324

ELECTRIC SIGNALING, SUPBRVISING. AND RECORDING SYSTEM CONTROL PANEL.

Filed July 14, 1931 15 Sheets-Sheet 2 LIN! TEST OSCILLATOR SIGNAL cmcurr SELECTOR STEP-UP 4146 Low PAPER 4441 35 PRINTING 4132 snourm TE! HELAY v ,gm #2 y 1939- J. R HARRINGTON 2,164,324

SUPERVISING, AND RECORDING SYSTEM ELECTRIC SIGNALING.

Filed July 14, 1931 15 Sheets-Sheet 3 July 4, 1939. .1. R. HARRINGTON ELECTRIC SIGNALING, SUPERVISING, AND RECORDING SYSTEM Filed July 14, 1931 15 Sheets-Sheet 4 July 4, 1939. J. R. HARRINGTON ELECTRIC SIGNALING, SUPERVISING, AND RECORDING SYSTEM Fi led July 14, 1931 15 Sheets-Sheet 5 y 4, 1939- J. R. HARRINGTON 2,164,324

ELECTRIC SIGNALING. SUPERVISING, AND RECORDING SYSTEM Fileg guly 14, 1951 15 Sheets-Sheet 6 July 4, 1939.

J. R. HARRINGTON ELECTRIC SIGNALING, SUPBRVISING, AND RECORDING SYSTEM 15 Sheets-Sheet '7 Filed July 14, 1931 P QyflM,M m. F

mm mwm mm July 4, 1939. J. R. HARRINGTON 2,164,324

ELECTRIC SIGNALING, SUPBRVISING. AND RECORDING SYSTEM Filed July 14, 1931 15 Sheets-$119958 y fiW M, m w QM dtrya July 4, 1939. J. R. HARRINGTON ELECTRIC SIGNALING, SUPEHVISING, AND RECORDING SYSTEM Filed July 14, 1951 15 Sheets-Sheet 9 July 4, 1939. .1. R HARRINGTON ELECTRIC SIGNALING, SUPERVISING, AND RECORDING SYSTEM Filed July 14, 1931 15 Sheets-Sheet l1 Qwm w ,s mmw mm m m kww @m w @0765 Fwd/ v"! July 4, 1939. J. R. HARRINGTON ELECTRIC SIGNALING, SUPERVISING, AND RECORDING SYSTEM Filed July 14, 1931 15 Sheets-Sheet 12 July 4, 1939. J. R. HARRINGTON ELECTRIC SIGNALING, SUPERVISING, AND RECORDING SYSTEM Filed July 14, 1931 15 Sheets-Sheet 13 July 4, 1939. J. R. HARRlNGTON 2,164,324

ELECTRIC SIGNALING, SUPERVISING. AND RECORDING SYSTEM Filed July 14, 1931 15 Sheets-Sheet 14 July 4, 1939. J. R HARRINGTON 2,164,324

ELECTRIC SIGNALING, SUPERVISING. AND RECORDING SYSTEM Filed July 14, 1931 15 Sheets-Sheet 1U ALARM No.5 1 5 DOEaCO-IQZIJUNE I E6 25 ALARM NO. 3 j 5 DOECOJQZIJUNE4 E6 25 VALVE OPEN 9' 1 2 DOE&Co.l95IJUNE4 4 2 VALVE (ILSDZ 1 Z DOEgCoJQBIJUNM 54 I6 ALARM NO- 6 1 4 jDOE C 0J95UUNE4 54 I5 ALARM NO. 3 i 4 DOEgCoIQBUUNE l 54 I5 Patented July 4, 1939 UNITED STATES PATENT OFFICE ELECTRIC SIGNALING, SUPEBVISING, AND

RECORDING SYSTEM Application July 14, 1931, Serial No. 550,739

41 Claims.

The present invention relates to electric signaling, supervising and recording systems of the type characterized by a plurality of control boxes or stations interposed at diflerent points in a connecting circuit and so arranged that when an alarm or like condition arises at or in the vicinity of one of these boxes, or when a change occurs in the condition of certain apparatus being supervised by the system, or when one of the boxes is manually energized, the system will function to give a signaling or supervisory indication, which indication may audibly designate the particular box which has been energized in the system, and will also make a permanent record designating the particular box and the condition which gave rise to the energization of that box.

The present invention embodies improvements on and developments of the electric signal system disclosed in my prior Patent No. 1,950,108, granted March 6, 1934.

Apparatus of the present type has application to sprinkler alarm systems, supervisory systems, fire alarm systems, burglar alarm systems, and

other analogous systems where it is'desired that a 5 certain condition or operation occurring at any one or more points along the circuit shall give an alarm or signal indication, or shall exercise a supervisory or regulating indication or control in connection with apparatus associated with the signal system. The system forming the subject matter of the present application embodies certain improvements which are particularly adapted to the fire prevention apparatus of a building or buildings, including means for indicating when any branch or spray head of a sprinkler system is operating; for indicating when the air pressure on a pressure fed water supply system is high or low or when the water level, as of a gravity fed system, is high or low; for indicating when any 4 of the main control valves of the sprinkler system are open or closed; for indicating when the power, as of an electrically operated pump, is available or has been interrupted; and for indicating when room temperatures rise excessively,

45 or indicating other conditions having to do with a fire prevention system. Accordingly I shall describe the invention in such situation, but it will be understood that the fundamental features of,

ically, this recording apparatus makes a record of each alarm or supervisory indication, designating the particular box or boxes from which the indication was transmitted, the condition at that box which gave rise to the indication, and preferably 5 the date and the time of day when the indication was transmitted. Such record is permanently printed on a sheet or preferably a continuous paper tape, so that it afiords an instantaneous visual indication of the particular box operating and 10 the condition at that box, and so that the record can be checked for past performance of the system, and for building maintainence and supervisory records.

Another object of the invention is to provide 1 improved recording apparatus of the above general despription which will function in a system of the successive, continuously repeating, noninterfering type. In this regard, it is a more specific object of the invention to provide re- 50 cording apparatus for the general type of signaling system disclosed in my copendlng application above referred to. Certain of the fundamental principles, features and structures characterizlng this prior system have been incor- 5 porated in the present system herein disclosed. For example, in such system interference between ditferent boxes or stations is positively avoided. Thus, in the event that two boxes should be energized simultaneously, or in the so event that one box should start to operate while another box is operating, no interference results between said boxes, but instead the two boxes take the line successively, one completing its indication on the circuit and the other box 35 awaiting its turn and thereafter starting and completing its indication on the circuit. This successive, non-interferring operation will occur no matter how many boxes are energized either simultaneously or in overlapping sequence. mirthermore, in such system the boxes are successively operating and continuously repeating. Thus, in a long series of boxes, if box A should first be set into operation and box B should then attempt to operate, the latter would be compelled to await its turn until box A has completed its cycle of alarm or supervisory indication, when box B would begin operation and complete its cycle of indication; and it the condition which started the operation of box A had not been corrected up to such time, box A would again take up operation and complete a second cycle, and, similarly, if the condition which initiated the operation of box B had not been corrected up to this time,-box B would again take up operation abnormal conditions at the boxes are corrected.

Moreover, such successive, continuously-repeating operation will occur irrespective of the number of boxes entering into operation and irrespective of the location of the boxes in the series, represented for example. by boxes A, C and D or B, E. F and G. etc. This continuously-repeating characteristic is of decided importance in safeguarding the system against all contin gencies. For example, in prior systems where the alarm or supervisory indication is only sounded or indicated once or a limited number of times, if the watchman is absent from the building for only a short time and the alarm or other indication should occur during this interval the protective value of the system is nullified. A further feature of this system is that the movable transmitting element in each box is electrically driven. Heretoi'ore. in the majority of these electric signal systemsthe signal wheel or like transmitting element has been driven by clock-work mechanism. Such mode of operation imposes definite limitations on the system. For example. the box cannot have a continuously repeating function because the clock spring motor runs down in a comparatively short time. Furthermore in the majority of these prior systems, after an operation of the system; the clock spring of each clock which has operated must be rewound immediately to restore the system to its former protectivercondition, which is an obvious disadvantage. In the system disclosed in this and in my prior application the transmitting element in each box is driven by power derived from an electric circuit passing through all of the boxes. Such circuit supplies energy to an electromagnetic motor element in each box which functions to drive the transmitter element through repeated cyclical movement as long as the alarm or supervisory condition continues at that box. Preferably, this electromagnetic mctor element in each box is of the step-by-step type adapted to be advanced by current impulses transmitted over the box operating circuit, such intermittent impulses being created by a circuit breaker or pulsator which is automatically set into operation when one of the boxes is energized. This pulsator also establishes current impulses in the system which are used in appropriately advancing the printing wheels of the recording mechanism, from which the printed record is made.

The recording apparatus herein disclosed cooperates with the above described characteristic features of the system, in that this apparatus will record the successive operations of a group of concurrently or successively energized boxes, having any sequence in the series, such as boxes A, C and D or B, E, F and G, and in that this apparatus will record the continuously repeated operations of any one box or of a group of boxes operating successively, all without interfering with the above described operation of the boxes.

A further object of the invention is to provide improved means for enabling the transmitter of any energized box to move the printing elements of the recording apparatus to their proper positions for designating the energized box and also for designating the condition which caused the energization of that box. In this regard, one of the particular objects of t c inamass vention is to provide an improved method of and means for eflecting a selector function whereby the code impulses designating the particular box and the condition prevailing at that box cause selective actuation of the di'ferent printing elements in their proper sequence for establishing the proper printing set-up in the recorder. For example, in a large installation the boxes are preferably designated by numbers having three or possibly more digits, such as box No. 313 or 315, the successive digits of which number are set up in printing position on three type wheels corresponding to hundreds, tens, and units wheels, and the first duty of the selector function is to transfer the code impulses selectively to the proper numeral wheels. The particular condition existing at that box is also set up in printing position on a separate type wheel which I have termed the condition" wheel, and another duty of the selector function is to transfer the proper code impulses to this condition wheel for giving it the proper printing set-up. After the entire printing set-up has been established on the type wheels the printing operation automatically follows, whereupon all of the type wheels are then automatically restored to their initial positions, the paper tape is automatically advanced to the next printing position and the inked printing ribbon is also advanced. This cycle of selectively setting up the type wheels, automatically printing this set-up, and then automatically restoring the recorder parts for a later printing operation, is repeated as long as any energized box continues to repeat its signaling cycle, and in .the event of a group of boxes operating concurrently the recorder apparatus will go through this same general cycle, modifying the set-up of the numeral and condition wheels, however, to correspond with the number and condition of the box then having the line so that the printed record will show exactly the sequence in which any number of boxes came into operation and the number of times and the order in which they repeated, all without interfering with the operation of the boxes.

With reference to the recorder apparatus, other obiects' of the invention are to provide improved automatically operating means for: (1) effecting the printing operation at the proper time in the cycle: (2) restoring the type wheels to their initial positions preparatory to again being set-up by the code impulses; (3) advancing the paper tape to its next succeeding printing position; (4) advancing the inked printing ribbon (and automatically reversing the direction of advance of the ribbon near the ends thereof) (5) indicating when the supply of paper on the feeding roll is low; and, (6) protecting the system during the interval of substituting a new roll of paper tape by opening the box-operating circuit and the selector or signaling circuit so as to prevent the transmission of any signaling impulses from any box which might be energized during this temporary non-operative condition or the recorder apparatus.

The selecting or sequence controlling function, by which the code impulses are selectively transferred to or made effective on first one and then another of the-several type wheels, involves a unique relation between the circuit for operating the boxes and a second selecting or signaling circuit, together with certain selector or sequence appartus cooperating with the circuits. One group of code impulses is transmitted to a step-up electromagnet which steps up one of the printing wheels to its printing position, then a selector or sequence electromagnzt operates to render the advancing pawl of this wheel inoperative and to render the advancing pawl of another printing wheel operative, whereupon succeeding impulses advance this second wheel to its printing position, etc. This operation of having the step-up electromagnet advance the ,printing wheels and haying the selector electromagnet determine the wheel which is to be advanced is followed until all of the wheels are stepped up to 'their printing positions, whereupon the printing operation follows. This selector function and its apparatus constitute one of the principal features of the invention.

Another object of the invention is to provide an improved system of the above general description wherein definite and positive synchronization is established between the operation of any signaling box and the operation of the recorder. This synchronization is effected electrically by a synchronizing device which is common to all of the boxes on the circuit and to the recorder; in the preferred embodiment herein disclosed such synchronizing device being the above mentioned oscillating circuit breaker or pulsator which transmits current impulses to the operating box and to the recorder. Diificulties of major importance have heretofore arisen in endeavoring to establish and maintain synchronized timing between the prior types of clock spring driven boxes and the prior types of recorders. Mechanical escapements have been associated with such boxes to control their speed of operation, and mechanical escapements and other like mechanical timing devices have been associated with the recorders to govern the selection or change-over from the energization of one coil to the energization of another .0011. For example, when one of these prior signaling boxes is transmitting code impulses corresponding to two or more digits, it is the intention that in each group of impulses designating one of these digits there shall be a uniform time interval of relatively short duration between the successive impulses in this group, and that there shall be a relatively longer time interval between any two such groups of impulses. The timing device at the recorder is intended to distinguish between the length of .time interval between impulses of a group and the length of time interval between groups of impulses, in order to select the proper coil for energization. Manifestly, however, there is always a great deal of uncertainty in the time intervals between impulses transmitted from a clock spring driven signaling box, arising from wear of the parts, changes of temperature afiecting the lubrication, foreign matter collecting in the working parts, etc.; and these sameconditions and uncertainties prevail in the case of the time measuring device at the recorder. Hence, there is no definite' and positive synchronization between the box and the recorder, and errors frequently arise in the performance of the recorder, and always remain as potential sources of unreliability. These objections have all been avoided in my improved system wherein the oscillator functions as a synchronizing element common to the boxes and to the recorder for insuring that precisely the same time interval shall exist between successive operations of the box and the transmission of successive impulses to the recorder.

tinuous test so that in the event of breakage of any of the conductors, or a ground being established on any of the circuits, or a fault arising in any of the apparatus, a trouble signal will instantly be energized to indicate that the system is not in its normally operative condition, and to designate the source of the trouble.

Another object of the invention is to provide an improved electrically operated step-by-step transmitter for use in each of. the boxes or control stations, which requires less energy to operate, which is more reliable in its operation, and which embodies other controlled and controlling functions not disclosed in prior types of transmitters.

Another object is to provide an improved signallng system and improved box transmitter in which the current impulses transmitted over the box operating circuit are operative to actuate the transmitter armature, but wherein the code wheel or rotor element of the box is not advanced by the attracted movement of the armature on the current impulse, but instead is advanced by the recessional movement of the armature upon the cessation of the current impulse. This mode of operation has numerous advantages which I shall hereinafter describe.

Other objects and advantages of the invention will appear from the following detailed description of a preferred embodiment thereof. In the accompanying drawings illustrating such embodiment:

Figure 1 is a fragmentary circuit diagram illustrating schematically a series of signal boxes or control stations and the circuit wires connecting with these boxes, this figure representing the line portion of the system;

Figure 2,is a fragmentary circuit diagram illustrating the circuits and apparatus constituting the control panel or central station of the system, this diagram being adapted to be joined with the right-hand edge of Figure 1 for completing the entire system circuit;

Figure 3 is a rear elevational view of one'of the step-by-step electromagnetic motor units employed in each of the signal boxes;

Figure 4 is a side elevational view of the same;

Figure 5 is a front elevational view of this device; l

Figure 6 is a horizontal sectional view taken approximately on the plane of the line 6-6 of Figure 5;

Figure 7 is a view diagrammatically illustrating the electrical connections in a typical signaling box, particularly where such box has a flow indicating or fire alarm signaling duty;

Figure 8 illustrates the control circuit connections of a box having a typical supervisory duty;

Figure 9 is a front elevational view of the pulsator or oscillator which transmits the current impulses to the signaling boxes and to the recorder and system;

Figure 10 is a perspective view of the selecting switch or relay which directs these impulses selectively either to the selector coils or to the type step-up coils of the. recorder;

Figure 11 is a perspective view of the other side of this same selecting or directing switch;

Figure 12 is a front view of the recording ap paratus, a portion of the casing thereof being broken away to illustrate certain operating parts;

Figure13 is a transverse sectionalview through the mechanism for selecting and advancing the type wheels of the recording apparatus, this view 75 corresponding to a section taken approximately on the plane of the line "-18 of Figure 14;

Figure 14 is a view taken approximately on the plane of the line i4ll of Figure 13, and with the front and top portions of the housing removed, showing in front elevation this same mechanism for selecting and advancing the type wheels;

Figure 15 is a transverse sectional view taken approximately on the plane of the line l5l5 of Figure 14;

Figure 16 is a view from the same side as Figure 15, but also illustrating certain of the mercury tubes associated with the recording apparatus, and showing some of the mechanism which controls the tilting of these tubes;

Figure 17 is a sectional view on a larger scale, taken between the planes of Figures 15 and 16, approximately as indicated by the section plane li-i'l on Figure 14;

Figure 18 is an end elevational view of one of the type wheels, showing the return spring which restores the wheel to its normal position;

Figure 19 is a side elevational view of the same;

Figure 20 is an inverted view looking upwardly under the aforesaid mercury tubes, illustrating their mountings and some of their actuating mechanisms;

Figure 21 is a plan view showing the mechanism within the base portion of the recording apparatus, below the mechanism which selects and advances the type wheels;

Figure 22 is a transverse sectional view taken approximately on the plane of the line 22-22 of Figure 21, showing the operating relation of the parts which enter into the printing operation;

Figure 23 is a fragmentary transverse sectional view taken approximately on the plane of the line 23-43 of Figure 21, showing the pawl apparatus which advances the roiler parts feeding the p p r t p Figure 24 is a fragmentary view showing a portion of the paper tape having typical data recorded thereon; and

Figures 25 and 26 are diagrammatic views of modified constructions.

Referring first to Figures 1 and 2, the main operating units of the system consist of a series of signal boxes A, B, C, etc. and a control station or panel generally indicated at X, this control station or panel comprising a grouped arrangement of apparatus for recording the impulses transmitted from the boxes, for transmitting the intermittent current impulses over the circuit, for maintaining the circuit under continuous test, and for performing the various other functions hereinafter described. While Figure 1 only illustrates three boxes A, B and C, it will be understood that any number of boxes may be included in the system depending upon the number of locations or operating stations from which an alarm or supervisory indication is to be transmitted. The entire group of boxes is connected in series relation to a circuit consisting of three conductors P, N and S. It will be noted that these conductors loop back from both ends of the circuit, or from both ends of the' series of boxes, to the control panel X. The circuit of the entire system is completed by placing Figure 2 in juxtaposition to the right-hand edge of Figure 1. v

I shall first describe the structural details of one of the signal boxes, and then of the recording apparatus and of the other mechanical devices associated with the control panel, and shall then describe in detail the various circuit functions and operations intheir relation to the several units of the apparatus. The explanation of the entire system will be most easily understood if we assume the system to be operating on direct current with certain conditions of polarity or directions of current feed, as this will enable the circuits to be traced through with respect to positive and negative. However, the same operation occurs when the system is operating on alternating current, and accordingly it will be understood that where I refer to positive" and negative in this description and in the appended claims I am not using these terms in a limitative sense, but only for the purpose of diflerentiation and to facilitate understanding the invention. The system might be operated entirely oil an ordinary lighting or power circuit but it would then be fallible because of the possibility of interruptions in the service line, and to avoid this I prefer to employ a battery 33 (Fig. 2) for energizing the more essential circuits of the system, this battery being floated across any suitable type of charging means. Leading from this battery are positive and negative feeders or buses I4 and 35 respectively, which have connection with the various devices and terminals at the control station X. The conductor P and N represent a box operating. circuit for supplying operating current to the severalboxes A, B, C, etc., and either polarity may be impressed on these conductors. It will be assumed, however, that positive polarity is impressed on conductor P, this polarity being supplied from the battery feeder 84 to the terminal designated PL ("positive line") on the control panel x From here the polarity is fed through conductor P in a direction extendin down through boxes A, Band C in the order named, and is thence conducted back to the terminal PR (positive return) on the control panel. It will be observed that this corresponds to a counter-clockwise direction of flow'in the particular circuit connections illustrated. It will also be assumed that the negative polarity from the negative battery feeder 85 is being placed on the opposite end of the conductor N through negative line terminal NL on the panel so that this polarity is being fed up through the series of boxes C, B, and A in the order named, and is being returned to the negative return te inal NR on the panel. It will be observed that such corresponds in the diagram to a clockwise direction of impressed polarity. The positive return PRis connected, to one end of the winding of a positive line test relay 36 and the other end of this relay winding is connected through a pulsator and other apparatus to the negative feeder 35 of the battery. The negative return NR is connected to one end of the winding of a. negative line test relay 38, and the other end of this winding has connection through positive polarity feeder 34 with the positive side of the battery 33. The arrangement is such that under normal conditions a small current flow is being pulsations are also transmitted to the actuating coils of the recorder mechanism for advancing the type wheels. The conductor 8 functions as a signaling or selecting conductor, extending in alo'opthrough the seriesofboxesandconnectingatitsendswiththetermin'alsfl ands on the control panel 1: Normally a testing current is being passed continuously through this conductor, the positive polarity oi this testing current being conducted through positive feeder branch 84' and being impressed on the conductor 8 at the terminal BI, and the negative polarity being conducted through resistance element It and being connected to the signal conductor at the terminal 82. This conductor 8 controls a signaling ,or selecting relay. CI. The control panel connections between the various relays. pulsator, recorder actuating coils, etc. will be hereinafter described in the more specific description of the circuit connections.

Referring now to the general adaptation of thepresentsignaling and supervisingsystemtoa typical fire prevention sprinkler installation, the riser of such an installation is indicated at 44 in Figure l. Thisriserextendsupthroughthe different floor levels of the building, such floor levelsbeingindicated atll,andservestoconduct the water to horizontally extending floor branch mains 46 which extend out from the riser generally below the ceiling of each floor level. These fioor branch mains may have the conventional sprinkler heads 41 mounted thereon. although most generally they connect to various "stringers" 4B radiating out in different directions, which stringers have these sprinkler heads mounted thereon. As is well known. these sprinkler heads are designed to open automatically in the event of fire to produce a sprayed discharge of the water over the fire area. In a building of even moderate size there are usually several risers M from which radiate floor branch mains 48 at each fioor level. The present invention contemplates associated an individual signal box with each iioor'branch main leading from each of these risers.-so that when any sprinkler head in the system begins operating such fact is indicated by the present alarm system, and the location of this particular head is also signaled in the alarm, as by a code which designates the particular riser and the floor branch main with which this head is associated. Similarly, if different heads in different parts of the building commence operating either simultaneously or in sequence the alarm signal will designate the different sections of the building in which these heads are located. This feature of announcing or signaling the exact location of the operating head or heads is obviously of great advantage as it enables the flre to be located at once, which is of extreme importance in large or widely scattered buildings, and moreover in the event of a sprinkler head opening accidentally, it enables this head to be located promptly before great water damage can be done. As will hereinaiter appear, the designation of the particular floor branch main is effected by an individual code in which the alarm is sounded and also recorded. If desired; separate signal boxes might also be associated with each stringer 48, but this is not usually necessary. The main fire alarm duties of the system are exercised by boxes associated with each floor branch main, and made responsive to the flow of water through that main, under the control of flow responsive switches generally indicated at 49. In Figure 1 I have shown the boxes A and B as having this alarmduty in connection with fioor branch mains with which they are associated. In exercising its supervisory duties in connection with a sprinkler system,

separate mailboxes may be associated with different apparatus and having to do with a typical installation, whereby the system will have a supervisory function in indi-- adjacent to the riser ll so that the fioor branch main can be cut off in the event of an accidental opening of one of the sprinkler heads, or for the purpose of making repairs, extensions, etc. Naturally, a critical hazard is immediately introduced if this manually controlled valve should be closed and then forgotten. The present system provides means for positively preventing any such possibility by exercising a. supervisory control for indicating the condition oi each of-these valves. For example, in Figure 1 I have shown the box C in a supervisory duty for indicating when the valve ii is closed and for indicating when thisvaive is opened. As I shall hereinafter explain, this particular supervisory duty is merely typical of a large number of other supervisory functions which may be embodied in the present system, as for indicating high and low water levels in a storage tank, the existence of air pressure on a pressure fed system, and such other supervisory iunctions as I have generally referred to in the i'orepart of this specification.

Signal'boxes Theterm "signal box" or signal station" is hereinafter usedin its generic sense as designating each of the devices from which the signal or control function emanates when said device is energized either manually or automatically. The

operating parts of all of these signal boxes A. B, C, etc. are duplicates, with the single exception of the arrangement of the code or signaling contacts, and hence a description of one box will suffice for all. Referring to Figures 3, 4, 5 and 6, the principal elements of each box include an electromagnetic coil M, an armature 55, a pawl 56 oscillated by the latter, and a rotary element 51 having a ratchet wheel 68 to which a stepby-step advancement is imparted by the pawl 56, and which rotary element 51 governs the coaction between certain contacts associated with the box operating circuit and with the signaling or selecting circuit. Referring more specifically to the detailed construction, the device is assembled upon a supporting or base plate III having a downturned flange 62 at one side by which the plate can be secured to any suitable support. Secured to the bottom of said plate in an insulating connector block 64 in which are mounted the connector terminals adapted for connection with the box operating and signaling circuits and with the circuit or circuits which govern the energi zation of the box. Wires extending from these terminals pass up through an insulating bushing 65, passing through the base plate, and extend up to their respective contacts and connections associated with the rotary element 51, as I shall hereinaftei describe.

The coil and armature assembly is carried by a O-shaped plate 66, the lower arm of which is secured to the base plate 6| by the insulated bolts or studs 61. The electromagnetic coil 54 is suspended from the upper arm of the c-shaped bracket 68 by a screw 68 passing down through said arm and threading into the core 69 of the coil. A cap Ill composed of copper or like nonmagnetic material is secured over the projectin

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