US2306820A - Sound signal apparatus - Google Patents

Description

Dec. 29, 1942. J. R. M cKAY SOUND SIGNAL APPARATUS Original Filed March 14, 1938 4 Sheets-Sheet 1 M w a v INVENTOR. JZkn R fiat/fag W C. Km

HTTOIFNE) Dec. 29, 1942. J MacKAY 2,306,820

SOUND SIGNAL APPARATUS Original Filed March 14, 1938 4 SheetsSheet 2 IN V EN TOR.

65 [76 166 fa/mfi Manfaq WM QKW Dec. 29, 1942. J, R, Ma CKAY 2,306,820

'SOUND SIGNAL APPARATUS Original Filed March 14, 19:58 4 Shets-Sheet 3 I I/ IMF INVENTOR.

.fflim if. Mar/fay 252 BY WCMKMA Patented 29, 1942 Jolm R. MacKay, West Caldwell, N. 1., assignor to Wallace & Tier-nan Products, Inc., Bellevllle, N. 1., a corporation or New Jersey Original 1940, Serial No. 329,060

11 Claims.

This invention relates to sound Si nal apparatus, and more particularly to signalling or alarm devices of electrically operated t pe, such as horns, and to control means for signalling apparatus of the character stated. An'e'specially advantageous use or embodiment of the invention is in fog horns, wherein ruggedness, power of sound, and dependability over long periods} of application March 14, 1938, Serial No. Divided and this application April 11,

and without conflict between the signal current controlling and current reversing means. 4

Other objects are to provide, relative to fog horns and like signal apparatus, generally sturdier and more reliable arrangements of operating and control elements.

v Other objects and advantages include those .which are hereinafter stated or apparent, or

time are important criteria. Such horns are I often used on floating buoys, and the require ments of a satisfactory horn for such use are particularly severe. suitable for use on buoys, where they will be subject to continuous operation, exposure to the-elements and to frequent submergence, and to operation at all angles due to the swinging and listing of the buoy. As buoys are frequently collided with, all parts of the horn'and program mechanism must be of such construction that they will not be damaged or operation aflected by any jar or bump which'the buoy may receive, other than one where the horn or mechanism is actually hit and damaged in consequence. It is a common requirementof horns so used, that they must sound from two to four blasts of All parts must be of a type about-one second per minute, and that this operation is continuous for 24 hours-per day for each day of the year.

In general, sound signals such as fog horns have comprised an 'electromagnet, an armature, a diaphragm associatedwith the armature, and make-and-break contacts operated. buzzer fashion, by the armature.

One object of the invention is to provide apparatus of the character described having satisfactory power and pitch characteristic, which is at ing means for synchronously controlling both the signal characteristic and a reversal of current flow through the horn contacts and associated current controlling contacts, periodically the enclosed parts, including the elements 25.

which are incidental to the invention. The nature. of the latter will be conveniently explained by reference to the following description and accompanying drawings, which set forth, by way of example, certain presently preferred embodiments of the invention.

In the drawings:

Fig. 1 is an elevation of a complete fog horn and control unit embodying the invention;

Fig. 2 is an enlarged longitudinal section of the horn and its operating parts;

Fig. 3 is a plan of the upper end of Fig. 2;

Fig. 4 is a section on line 4-4 of Fig. 2;

Fig. 5 is a general wiring diagram; and

Figs. 6 to 8 inclusive are diagrammatic views of other modifications, including various arrangements for automatic current reversal.

As generally shown in Fig. 1, the sound signal device and its associated control instrumentalities may be conveniently combined in a single unit, comprising an open-mouthed trumpet or bell 20, bolted to a housing 2| for the'homdriving elements, the housing being in turn secured to a case 22. The latter encloses an electricmotor unit 23, having associated program cams and contacts as hereinafter described, and

also encloses fuses and a relay 24 for operating the horn. Certain adjustable elements of the horn proper, generally designated 25, may be disposed within the casing 22, and the face oi the latter shown in Fig. 1 may conveniently comprise a door or cover plate hinged (at 26a) to open upon release of the toggle bolts 26, for access to For convenience -of access and adjustment the parts generally designated-23 and 24 are mounted on the inside of the door and are swung out of the casing with it. It will be understood that particularly where the apparatus is to be used at sea or ofl shore, as on a floating buoy, or where it is otherwise to be exposed to weather or moisture, the entire assembly of casing 22, housing 2| and the inner end 21 of bell 20, must be thoroughly water-tight. To that end, the peripheries ofdiaphragms, interposed gaskets, and other Joined elements, may be embedded in waterproof plastic material, such as glyptol'lacquer'. A coneportions 32 terminating in the same plane as the pole ii, to provide adjacent pole elements of opposite polarity, for powerful signal action; the magnet winding 33 is conveniently disposed about the central pole member 3|, as shown. The central portion of the field core, via. the pole member 3|, is conveniently provided with a longitudinal hole or tunnel, to admit a tubular shaft or connecting member 34 which is part of a the vibrating assembly hereinafter described. The hole or tunnel is conveniently lined with a copper tube 34a, pressed in place, to, prevent displacement of the laminations of the member 3i and to guard against an accumulation of rust in the hole, which might otherwise interfere with free movement of member 34.

The diaphragm structure of the horn advantageously comprises a plurality of relatively thin diaphragms disposed in parallel and preferably.

arranged so that the distance between the diaphragms at the respective ends or the entire set is of substantial extent. For example, in the construction shown, there are provided two groups of diaphragms 35 and 36, separated by a substantial space; the inner diaphragm group 35 conveniently comprises three diaphragms 35a spaced slightly apart, while the group 38 comprises two diaphragms 36a; likewise spaced slightly apart. The diaphragms are peripherally retained to the housing 2| by a plurality of bolts 31, circumferentially spaced around the assembly. Thin supporting rings 38 serve to space the diaphragms within the respective groups, and the groups are separated by a cylindrical spacing member 33, and all parts are preliminarlly retained in place by the bolts 31 and securely clamped to the housing 2| by a plurality of bolts 43 spaced around and passing through a flange on the bell or trumpet 23, whereby the latter is also clamped against the diaphragm assembly and housing 2|. It will be noted that the annular face of the bell which abuts against the diaphragm assembly, specifically the outer diaphragm group 36, is provided with a relatively wide annular groove 4|, so that the area of contact between the hell or horn proper, and the diaphragm assembly, is confined to a pair of spaced, concentric and relatively narrow annular paths 42 and 43, affording an extremely close fit of the bell 23 against the diaphragm assembl and the housing.

' The several diaphragms a. and 36a. are centrally piercedby-and secured to a sleeve 45,

having its interior in threaded engagement with the outside of tube 34. Intermediate the several diaphragms of each group on the sleeve 45, central spacing washers s are provided for accurately spacing the diaphragms at the center, and when the assembly is made up, the ends of the tube 45 are advantageously upset or riveted against the heavy terminal washers 45b, whereby each diaphragm group is firmly secured against its corresponding shoulder 450 on the tube 45. The oppodte end of the tube 34 on the other side of the electro-magnet 33, is seated in an armss,soo,sso

ture 43, which comprises laminations of iron or preferably steel in the same plane as laminations of the neld core 3i, 32, and which is disposed in proximity to the poles of the latter. A long bolt 41 extends through the tubular shaft 34 into threaded engagement with a member 43, which provides an extension for the shaft 34 beyond the armature 43, and into which the bolt 41 may be tightened so that the head of the latter engages a lock washer 48a against a large knurled washer 49 which is keyed to the shaft 34 and abuts the end of sleeve 48, and the sleeve is locked in adjusted position on the shaft 34. Before the bolt 41 is tightened, the knurled washer 48 may be turned to screw the sleeve 34 longitudinally in the sleeve 45 so as to adjust the air gap between armature 46 and the core 3|. 32.

It will be understood that in the preferred construction shown, the passage of shaft 34 through the hole in pole 3| (strictly speaking, through the tube 34a) is completely freei.e., there is no contact anywhere-and indeed the shaft is entirely clear of supporting engagement or abutment at any point above the diaphragm assembly as seen in Fig. 2. That is, the spaced groups of diaphragms 35 and 38, serve alone, and very satisfactorily, to support the remainder of the vibrating assembly, including shaft 34 and the driving armature 46. Frictional, spring or other supplementary supports for the vibrating instrumentalities are thus entirely eliminated, and at the same time the arrangement is such that the respective positions of the various parts carried by or connected to the shaft 34 may be readily adjusted and the parts accurately locked in adjusted position. Furthermore, by virtue of the inclusion of a plurality, and preferably a multiplicity, of spaced parallel diaphragms which are each relatively thin, an eminently desirable stiffness is obtained for the diaphragm structure without tendency of breakage on the part of its individual constituents. In other words, the diaphragm arrangement may safely be stiff enough to provide a desirably high pitch, although a relatively heavy armature 46' is used to obtain powerful driving action. For example, a horn of, the type shown has been satisfactorily constructed to produce a note of 205 to 210 cycles per second, yet strong enough to be heard clearly for several miles, under average listening condit ons.

The outer end of the member 48 carries one contact "a 'of' a pair of contacts generally designated 50, and arranged to open or close in accordance with longitudinal displacement of the shaft 34. The other contact 53b of the set is mounted on a spring 5|, conveniently secured to but insulated from the casing 22. To avoid flexing of its end portion, the spring 5i may have a reinforcing plate, or it may preferably have integral upwardly turned ears 52 along its sides, which not only reinforce the end of the spring, but enlarge its end area so as to prevent breakage adjacent the hole where contact b is mounted. The contact 5012, moreover, preferably has a tubular shank 50c whereby it is riveted in the hole of the spring, so that when the contact heats up in use, the shank may expand inwardly and avoid straining the spring ii. The outerwend of the spring 5| extends beyond the contacts and is adapted to strike an anvil member 53 which is thus arranged to limit the motion of the spring downward as seen in Fig. 2. The anvil member 53 advantageously comprises a worm gear mounted on a shaft which is threaded into a cross member 54 that is suitably insulated from the housing 2| and case 22 .(it being understood'that the housing and case are convenient- 1y bolted together at 55a, as shown). The lower end of the worm gear shaft has threaded on it a leaf spring 53a, which has its ends-abutting the under side of the member 54 and which strongly biases the worm gear in a downward direction to prevent play and chatter. A pin 53b, carried by member 54, engages a slot in the leaf spring 53a to prevent rotation of the latter.

A'worm .55 is journaled in suitable supports on' the member 54, for .rotative engagement with the gear 53, and is provided with a milled or engages'the teeth of the wheel 56; and the arrangement is such that by inserting a screw driver in the slot of member 51, and turning the same, the worm 55 will rotate the gear 53 and raise or lower the upper or anvil face of the latter with respect to the outer end of spring 5|. During suchadjustment the check 58 clicks over the teeth of wheel 55, but serves to lock the assembly in any adjusted position. The slotted shaft or head 51 is preferably insulated from the assembly of wheel 56 and worm 55, so as to prevent electric shock to the operator making. adjustments, or' inadvertent grounding should his screw driver also touch the metal casing. Preferably both the anvil 53 and contact spring 5| are of hardened steel construction, for maximum wear resistance. It may now be explained that the parts generally designated 25 in Fig. 1 may comprise the elements 51, 55, 53, 5| and 56, which and past its original position as shown in- Fig. 5, and the cycle is repeated. Other things being equal (except the current consumption) the amplitude of diaphragm vibration is dependent upon the space 62 intermediate the upper surface of anvil 53 and the outer end of spring 5| in its neutral or rest position; that is, the wider the space the longer the contacts 50 are closed during each stroke, and the greater the force exerted on the armature 46. It will now be seen that the described horn structure, including the worm 55 for varying the position of anvil member 53 with respect to the spring 5|, is provided with effective means for adjusting the amplitude of diaphragm vibration, so as to obtain and maintain the desired amplitude at all times and without excess current consumption.

When the horn is used for marine signalling purposes, for which it is notably adapted, it must draw a relatively substantial current in order to produce a signal sumciently powerful to be heard, say, for several miles. Under such circumstances for example, where the horn is located and hooked up, as on a floating buoy, to operate automatically at frequent intervals-long continued use is apt to wear down the surfaces of the rapidly operated contacts 50 (even though "a condenser 63 or a condenser-resistor unit, is

are thus readily accessible, through the door of casing 22, for inspection and adjustment. 1

It will be understood that the lower contact I also diagrammatically shown at the upper part of Fig.5, except that for purposes of simplicity the diaphragm structure is shown as a single dia-' phragm member 66. It will here be seen that the internal wiring arrangement of the horn is simply such that the winding 33 is connected in series with the contacts 56 across the input terminals 6|, the path from the contacts 56 to the lower one of the-terminals 6| being conveniently through ground as diagrammatically indicated. Actually, in the apparatus of Figs. 1 to 4, this grounded path extends from contact 50a through the shaft 34 and the diaphragm assembly, to housing 2|.

Assume for the time being that a suitable source of current, such as a storage battery, is connected across the terminals 6|. Contacts 56 are normally in closed position, and the winding 33 being thus energized, the armature 46 is attracted by the field poles 3| and 32. The contacts remain closed, i. e., the spring 5| follows the downward displacement of the armature" (Fig. 5), until the outer end of the spring strikes the anvil 53. The downward stroke of the armature and diaphragm assembly 4666 then continues, as will now be well understood, and upon the return stroke (initiated by the energy stored in the diaphragm), contacts 50 again tive positions in operation.- Fig. 5 accordingly shows a particularly advantageous arrangement for automatic intermittent operation of the horn, and at the same time, for avoiding or greatly reducing the wear on the contacts.

It has been explained hereinabove that the casing 22 may contain a motor 23, together with an associated cycling mechanism and a'horn controlling relay 24. As shown diagrammatically in Fig. 5, the electric motor 23, which may be energized from a pair of storage batteries and 66, connected in series, is adapted to drive a pair of cams 61 and 68. Although other motors may be satisfactorily employed in many cases, I prefer to use a motor of the type described and claimed in United States Patent No. 1,985,357, to Charles F. Wallace, for Electric motor apparatus; it will be understood that where the device is expected to operate continuously for long periods of time and without attention, it is desirable to employ a motor having the low current consumption, constant speed and general dependability characteristic of the patented motor.

Cam 6! is provided, for example, with two oppositely disposed rises or high spots 69, and a pair of normally open cam contacts 10 are arranged to be closed by each passageof a rise 69-thus in the instance shown, twice during each revolution of cam 61. Cam 68, which may be assumed close, and under a presently preferred adjust- 'ment with respect to the natural period of the to rotate at the same speed as cam 61, is provided with a single rise H, which is longer in extent than either rise 69 of cam 61, and -which is so disposed that it shifts at contact-operating follower l2 shortly before contacts 10 are closed by one rise 69 of cam 61, and keeps the follower in shifted position until after the same rise 69 (on cam 6'!) has passed the contacts 10 and permitted them to reopen. When shifted, the follower 12 is adapted to open the normally closed contacts 13 and to close the normallyopen contacts 14.

One of the input terminals 6| of the horn is and 66, and it will now be appreciated that, as-

suming contacts H to be closed, the horn is connected to battery 65 or battery 06 respectively according to whether contacts 13 or 14 are closed. Furthermore, since the sides of the batteries 65 and 66 which are connected together through the common connection 16 are opposite in sign, the current flow through the horn when contacts I3 are closed is in the reverse direction from the flow when contacts 14 are closed. The low-current relay 24 is conveniently used to avoid the association of heavy duty contacts with the timing cam 61 (although in some cases, heavy duty contacts may beused at and the relay 24 omitted) and the winding of the relay may be connected as shown, through contacts 10 to the midpoint I6 of the batteries, and also through the contact arm 12a and selectively through contacts 13 or H, to the other side of one or the other of the It will be appreciated, of course, that the number of rises 63 on cam 81 and correspondingly the use of one or more rises II on cam 68 may be varied to suit requirements of design or operation. In one embodiment of the invention, the arrangement has been that shown in Fig. 5, with the rises 89 of such length, and with the motor 23 driving the cam 61 at such rate (2 R. P. 101.), that the horn makes four one-second blasts each minute; and with continuous operation of that char- 'acter for a period exceeding six months-four blasts per minute, day and night-there was no appreciable deformation of the contacts 50 and very little appreciable wear.

It will be understood that the capacity of condenser 63 (for ease in mounting, two condensers 63 are shown in Fig. 3 and will be understood as connected in parallel) may be readily selected to coordinate the period of the electrical circuit with the natural period of the mechanical elements.

The arrangements shown in Figs. 6, 7 and 8 are, generally stated, modified forms of the current-reversing instrumentalities shown in Fig. 5.

- Referring first to Fig. 6, the horn is generally inbatteries in the same manner as the horn itself.

Assume now that the motor 23 is rotating the cams 61 and 68, in a counterclockwise direction, from the position shown in Fig.5. The rise ll of cam 68 first shifts the follower 12 so as to close contacts 'I4 and open contacts 13. Thereafter one rise 69 of cam 61 causes contacts 10 to close and the relay 24 is accordingly energized from battery 86. Energization of relay 20 closes its contacts 17, so that current is supplied to the horn, through its input terminals 6|, from bat tery (SS-contacts 14 being now closed. The horn continues to blow until the rise 69 passes contacts 10. opening them, thereby de-energizing relay 24 and opening its contacts 11 in the supply circuit to the horn. Thereafter, the follower 12 drops down from the rise 1|, and contacts 13 are closed. They remain closed during the time that the other or opposite rise 69 of cam 67 closes the contacts I0; and it will now be understood that when the contacts 10 are thus again closed to energize the relay 24 and operate the horn, both the relay and the horn are supplied from battery 65, and current fiows through the horn in the reverse direction from that during the immediately previous period of energization. In other words, as the motor 23 continues to drive cams 61 and 68, the horn is periodically sounded and the direction of current flow through it is reversed each time, so thatwear or other disturbance of the horn contacts 50, particularly as occasioned by transposition of metal between these contacts, is very greatly reduced; the action at the contacts 50 is thus, so to speak, a series of brief tendencies to carry the metal first one way and then back again respectively, so that over a long period of time the contacts are relatively unaffected by metal transposition.

It will be noted that the arrangement of cams 61 and 68 is such that contacts 13 and 14 are operated at times when no current is flowing, so as to avoid wear of these contacts by arcing. At the same time, it will be noted thatthe program contacts 10 and the heavy duty relay contacts 11 both benefit by the same reversal of current flow which is provided for the horn; in consequence, wear or other deformation of contacts 10 and TI is greatly obviated.

dicated at 200, the program cam at 20l, and the cam-driving motor at 202. Although a motor of thetype specifically illustrated in Wallace Patent No. 1,985,357, maybe employed,'I have indicated a form of motor shown and described in the patent of Wallace and MacKay, No. 2,181,841, granted November 2 8, 1939, for Motors and motor operated apparatus, wherein, a plurality of field windings are provided, successively energized by a plurality of batteries 203 and 2". The program cam MI is adapted to operate apair of contacts 205, which, when closed, cause energization of the winding 206 of a control and reversing relay. The circuit of winding 200 extends from ground, through contacts 205, conductor 208, winding 208, alternatively through contacts 209 or M0 to the positive side of battery 203 or the negative side of battery 204, and from the common return side of the batteries back to ground. Energization of relay winding 206 causes attraction of its armature 2H, and when the same is fully attracted, effects consequent closure of a set of contacts 2l2. Closure of contacts 2l2 causes energization of the horn 200, the circuit being from ground through the horn, contacts 2l2, alternatively through contacts 209 or 210 to the positive side of battery 203 or the negative side of battery 204, and from their common return point back to ground.

The armature 2| I carries a spring pressed pawl 2l3, which is adapted to engage the teeth of a ratchet 2H mounted for efi'ecting rotation of a reversing cam 2l5. The contacts 209 and 2| 0 are operatedby a follower 2| 6, on cam 2l5, whereby the contacts are alternatively closed in accordance with the position of the follower on a high spot or low spot of the cam. The arrangement of the pawl 2l3 and ratchet 2 I4 is such that upon downward displacement of the armature 2 (when it is attracted by the relay magnet 206) the pawl clicks idly past the ratchet teeth, and is pulled back by its springuntil a stop-arm 2| 8 carried by the pawl comes to rest against a pin 2|9a on the armature 2| I. By the instrumentalities just described, the pawl is so disposed on the downstroke of the armature, that upon a succeeding up-stroke it will not come into operative engagement with a tooth of the ratchet wheel 2| 4 until after contacts 2I2 have been opened by the release of the armature. Further upward displacement of the armature (under the influence of its spring 2l9 about a pivot 220) causes the pawl 2| 3 to engage the ratchet wheel 2M and rotate it, with its cam 21 5, in a counter-clockwise direction as seen in Fig. 6.

It may be explained that the arrangement of the pawl and ratchet is conveniently such that for each upward displacement of the armature the ratchet wheel and cam are rotated sufficiently for the follower 2H5 to move from a high not to a low spot or vice versa. For example, if the pawl is adapted to move the ratchet a distance corresponding to one tooth on each upward displacement of the armature 2| I, and if the cam 2l5 is provided with, say, six high spots, the ratchet wheel should have twelve teeth to effect the desired action.

It will now be seen that each time a high? spot of the program cam closes the contacts 205, the relay winding 206 is energized, and the contacts 2l2 are closed to eifect operation of the horn. Upon subsequent opening of the contacts 205, the relay is de-energized, the horn is first turned off by the opening of the contacts M2, and thereafter the upward operation of the armature'2l lso steps or displaces the reversing cam 2I5 as to by contacts 230, it will be readily seen that the reversing switch 233 is operated intermediate all successive closures of contacts by cam 61, and current flows through the horn in a reverse direction each time it is sounded. For convenience of illustration in Fig. 7, the circuit has not been shown so as to effect reversal of current through contacts 15, but it will be understood in view of the description of the preceding figures, that current reversal through these contacts may be easily provided. It will be further noted that, as in the case of contacts 73 and It in Fig. 5, the switch 233 is operated at a time when no current is flowing in the circuit of the horn motor, so as to avoid wear of the contacts of this switch.

In Fig. 8 a somewhat simplified arrangement is shown, which I now believe to be preferable the horn and through the winding of relay 206 is reversed for each operation of the horn, the reversing contacts 209 and 2H! being operated only at times when there is no flow of current, so as to avoid injury to these contacts, as explained in connection with contacts I5 and Id of Fig. 5. Furthermore," in the arrangement of Fig. 6 the reversing cam need not be specially designed for synchronism with the program cam 20!; that is, the program cam 20! may be readily modified or changed so as to provide any desired program of contact closure and horn operation, without in any way having to modify the structure of the reversing cam. It will be noted that as in the case of contacts '10 and ll of Fig. 5, the apparatus of Fig. 6 provides not only a reversal of current flow through the contacts in the horn mechanism 200, but also a reversal of current flow through contacts 205 and 2 l2, after each interval of horn operation.

The arrangement of Fig. 7 is in a number of respects similar to that of Fig. 5, with certain exceptions, including the provision of a separate reversing relay, arranged for operation of the system from a single battery or source of power.

The motor 23 rotates a program cam '51 and a reversing cam 68, as in the case of Fig. 5, and energization of the horn 20B is controlled by the contacts 1'! of a control relay 25, likewise similar to the relay 25 of Fig. 5. Instead of providing a set of reversing contacts mechanically associated with the reversing cam '58, the arrangement of Fig. 7 includes a single pair of normally open contacts 230 adapted to be closed by the high spot of cam 58. Closure of these contacts connects the winding of a relay 23!, across the battery 232, to energize the relay. The contacts of this relay are arranged as a double-pole. doublethrow switch, disposed in the circuit of the horn 200 and the battery 232, to provide for a reversal of the current through the horn, and also through the horn controlling contacts ll, each time the I switch is operated by energization or de-energization of the relay. Since the contacts 230 are timed by cam 58 in the same manner, with respect to cam 51, as contacts 13 and 14 in Fig. 5, and since the reversing switch 235 is controlled in a number of respects. The program cam 255 is driven continuously by the motor 23. which may be of the type of the Wallace patent previously mentioned, and which is energized from the battery 25!. A double-pole double-throw reversing switch 252 is provided intermediate the battery 25l and the horn 200, the latter being in series with its control contacts 253 that are closed by the high spots of the cam 250. It will thus be seen that through a ground connection, the horn 200 and contacts 253 are connected across the shiftable elements 255 and 255 of the reversin switch 252; and depending upon the position of the shiftable switch elements relative to their associated contacts, the horn is energized by a flow of current in one direction or the other from the battery 25l, when contacts 253 are closed.

For operation of the contacts 253 and other instrumentalities presently to be described, the cam 250 is Provided with a follower member 260 pivoted at 26l, and biased toward the cam by a spring 252, the arrangement being such that contacts 253 are not closed until the follower isapproximately fully lifted by a high spot of the cam, and are opened as soon as the follower starts to descend from a high spot. The reversing switch 252 is operated by displacement of a follower 253 on a reversing cam 25.5 which is incchanically connected for rotation by a ratchet wheel 265. A spring-pressed pawl member 266 is pivoted to and extends upwardlyfrom the program follower member 260, and is provided with an interior slot 26'! whereby it surrounds a group of teeth of the ratchet wheel 265, and is adapted, when pulled down by member 265, to rotate the ratchet wheel in a clockwise direction by engagement of the upper edge of its slot 261 with atooth of the ratchet. The arrangement is thus such that when the member 260 is moved up by a high spot of cam 250, the contacts 253 are eventually closed, but the pawl 255 clicks idly by the teeth of the ratchet. On the subsequent downward displacement of the member 26!), contacts 253 first open and thereafter the pawl 256 effects a predetermined step of rotation of the ratchet wheel and cam 26% as heretofore described. The arrangement of the ratchet wheel and cam 254 may conveniently be the same as that of corresponding parts 214 and 215, in Fig. 6, i. e., so that there is a reversing action of the switch 252 each time that the pawl is operated.

It will now be seen that the structure of Fig. 8 provides a simple and'eifective mechanically controlled arrangement for automatically reversing the flow of current through the horn and through its control contacts 253 after each interval of horn energization. Furthermore, as in the case of Fig. 6, the configuration of the program cam 250 may be varied or changed at will to provide any desired program of horn operation, without any modification of the reversing cam 264 or of the other instrumentalities for effecting the automatic current reversal.

The arrangement of Fig. 8 has certain advantages of economy and efiiciency over that of Fig. 6 and over other arrangements herein described: for example, all of the control apparatus is operated by the single motor mechanism 23, which may be of the notably efficient Wallace type (or Wallace and MacKay type) as hereinabove described, having exceptionally economical operating characteristics. No supplementary relays or magnetically controlled devices are needed and the current drain from the battery or other power source 25l is reduced to a minimum.

It will now be appreciated that the present invention not only affords a horn which is relatively simple in construction, dependable in operation, and easily built, to have any predetermined pitch within a wide range, but also affords distinctively improved control arrangements for such horns so as to avoid contact wear and impairment of normal operation. The advantages realized by the invention are, furthermore, of special importance where the signal device is to be automatically intermittently operated at frequent intervals and iii a location (as on a marine buoy) where it must give reliable service without frequent attention. On the one hand, the working vibration of the diaphragm and associated driving assembly is necessarily powerful, and tends to set up disturbing vibrations in every part that is mechanically connected with the apparatus; on the other hand, the electrical parts, notably contacts, are subjected to driving or control operation on each of the many hundred or often several thousand separate occasions on which the signal is operated every day. The invention is particularly effective in obviating or minimizing the wear or other derangement which would otherwise inevitably result from the strenuous operating conditions just described.

In accordance with the provisions of the patent statutes, I have herein described the principle of operation of my invention, together with the apparatus which I now consider to represent the best embodiments thereof, but I desire to have it understood that th apparatus disclosed is only illustrative and that the invention can be carried out by other means. Also, while it is designed to use the various features and elements in the combinations and relations described, some of these may be altered and others omitted and some of the features of each modification may be embodied in the others without interfering with the more general results outlined, and the invention extends to such use within the scope of the appended claims.

This application is a division of my copending application Serial No. 195,893, filed March 14, 1938, for Sound signal apparatus.

I claim:

1. Control apparatus for an electrically operated device having a supply circuit therefor, comprising switch means for effecting control of said supply circuit to operate the said device, said switch means being operable for successively effecting initiation and interruption of current supply in said supply circuit, said switch means having associated program means for repeatedly operating said switch means, for successively initiating and interrupting operation of said device in accordance with a program, means for reversing the direction of current flow in said supply circuit, and means controlled by said switch means and responsive to each operation thereof which interrupts current supply in said circuit, for operating the reversing means after each time the program means has caused operation of the said device.

2. The combination of claim 1, in which the last-recited means comprises electromagnetic means electrically responsive to said switch means upon operation of the latter to interrupt current supply to the aforesaid device, whereby the reversing means is operated only when no current is flowing in the supply circuit.

3. The combination of claim 1, in which the switch means includes a control element shiftable by the program means to effect closure of the supply circuit, and in which the means for operating the reversing means is mechanically responsive to the return displacement of said control element after the supply circuit has been opened.

4. Control apparatus for an electrically operated device having make-and-break contacts in an energizing circuit thereof, comprising circuitcontrolling contact means for opening and closing said energizing circuit at desired times, relay means for operating said contact means. a second contact means for controlling operation of the relay means, associated circuit-controlling means for intermittently reversing the flow of current through the make-and-break contacts and the circuit-controlling contact means and the second contact means to prevent impairment of operation of said device by wear of any of said contact means, and program means for'operating said second contact means and said associated circuitcontrolling means in accordance with a selected program.

5. Control apapratus for an electrically operated device, comprising means to connect said device with a source of current and including a set of contacts having means displaceable to close and open said contacts, and means operated by contact-opening displacement of said last-mentioned means for reversing the polarity of the source of current with respect to the aforesaid device and said contacts.

6. Control apparatus for an electrical device which is to be operated intermittently in accordance with a desired program and which has a current supply circuit therefor, comprising program cam means having selected camming characteristics, follower means intermittently displaced by the cam means and in accordance with the characteristics thereof, and circuit controlling means for the supply circuit, operated only in response to displacements of the follower means and including switch means for controlling operation of the electrical device, said circuitcontrolling means also including reversing switch means for intermittently reversing the direction of current flow through said electrical device and said first-mentioned switch means, in intervals intermediate operations of the electrical device. both said switch means being controlled by the follower means and operated only in response to displacements of said follower means and being arranged for operation in timed relation, under control of the cam means, whereby the reversing switch means is operated only when the firstmentioned switch means is open.

7. In combination, a circuit adapted to supply current to an electrical device, a program cam, a member displaceable by the cam, a switch operable by said member upon displacement thereof in one direction for closing said circuit, and for opening said circuit upon return displacement of the member, a switch connected in said circuit for reversing the direction of current flow through the electrical device and the first-mentioned switch, and means actuated by said member upona displacement thereof and timed to operate when said first-mentioned switch is in open circuit osition, for operating said reversing switch.

8. The combination of claim '7 wherein the re- .versing switch has a single operating member second-mentioned cam through said predetermined distance.

9. In combination, a current supply circuit, a switch having contacts in said circuit to be closed or opened, a control member therefor shiftable in one direction to close the contacts and in another direction to open the contacts, a reversing switch associated with said circuit for reversing the direction of current flow therein and through said contacts, and means operated by said control member upon displacement of same in one of said directions, for operating the reversing switch.

10. Control apparatus for an electrically operated device having a supply circuit therefor, comrising switch means for opening and closing said supply circuit to operate said device, means ineluding a programcam, for operating said switch means, means for reversing the direction of current flow in said supply circuit, means including a program cam, for operating said reversing means, and common driving means for actuating said cams in synchronism, said second-mentioned cam being arranged and timed relative to said first-mentioned cam, for operating the reversing means only at predetermined times when the supply circuit is open.

11. Control apparatus for operating, in accordance with a selected program, an electrical device having make-and-break contacts rapidly and repeatedly operated during each operation of said device, said apparatus comprising program cam means having selected camming characteristics, follower means intermittently displaced by the cam means and in accordance with the characteristics thereof, a current supply circuit for supplying the electrical device, and circuit controlling means for said circuit operated only in response to displacements of the follower means and including switch means for opening and closing said supply circuit in accordance with a program determined by the cam means, said circuitcontrolling means also including reversing switch means operated in response to said cam means and timed to operate only at times when the supply circuit is open at the first mentioned switch means, for intermittently reversing the polarity of electricalsupply in said supply circuit, to reverse the direction of current flow through the electrical device. JOHN R. MacKAY.

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