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Publication numberUS2573924 A
Publication typeGrant
Publication dateNov 6, 1951
Filing dateDec 31, 1948
Priority dateDec 31, 1948
Publication numberUS 2573924 A, US 2573924A, US-A-2573924, US2573924 A, US2573924A
InventorsChristian Miller
Original AssigneeEdwards And Company Inc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Audible electric signaling apparatus
US 2573924 A
Abstract  available in
Previous page
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Claims  available in
Description  (OCR text may contain errors)

Nov. 6, 1951 C, MlLLE-R 2,573,924

AUDIBLE ELECTRIC SIGNALING APPARATUS Filed Dec. 31, 1948 Patented Nov. 6, 1951 UNITED/STATES PATENT OFFICE Y 2,573,924 j l AUDIBLE ELECTRIC SIGNALINIG APPARATUS if VChristian 'Miller-,v Norwalk; Genn., assignor to Edwards andCompany, Inc., Norwalk, Conn., a

corporation of New York y Application December 31, 1948, Serial No. 68,698

iciaims. (c1. mm)

This invention relates to audible electric sig:- nalling mechanisms. and more particularly to electrically actuated ,bells and bliZZerS Midis a division of my application Serial Number 636,479, matured into Patent No. 2,465,111, of March 22., 1949...

Qne of the objects of this inventionV is to provide a compact, strong, dura-ble, and inexpensive .QQDStIuction of the above-mentioned character. Another objectisv to provide an electrically-actuated audible signalling device that will be of reliable action and Well adapted for manufacture and installation. Another object is t provide a, device of the abovementioned character in which the actuating mechanisms will be dependably housed and' in which access to the parts necessary for installing or mounting the device may be gained in a simple and facile manner. Another object is to provide a simple, inexpensive, and easily operable means for adjusting the relationship between an electro-magnet and its magnetically-responsiver coacting parts such as an armature to achieve the desired signalling action vof the device. Another object is to carry out the last-mentioned object in a manner to i of the complete device as it appears when infacilitate such adjustment either during manufacture Vand assembly or after' installation lof the device` Another object is to provide a signalling device so constructed that it may be readily'and easily set for selection of oneof severalv diierent kinds of audible signals, such'as musical or belllike signals and buzzer-like signals. Another object isV to. provide a combined bell and buzzer construction in which selection ofv either bell or buzzer action may be. achieved in a simple and dependable manner. vide a bell and buzzer construction in Which the operating mechanisms are eiciently housedV WithinY a bell-shaped or gong-shaped sounding element, yet so constructed that the mechanism.

Another object isk to DI,Q

may be selectively set for either bell action-"or buzzer action. Another object is. in general

provide an improved bell or buzzer construction, i

and other objects will be in part obvious or in part pointed out hereinafter.

The invention accordinglyconsists in the fea-V tures, of construction, combinations of elements, and arrangements of parts asrwill: be exemplified in the -structures to be hereinafter described `and indicated in the followingr claims.

In the accompanying drawing, which, is shown illustratively va preferred formcf thelvarious; possible `ambod-imeni's.of my invention.

Eialgis a t0n or plan: view, onA a. small-.scala the scope yof theapplication ofl which will be ,-5,0


2 is a. top plan view, on a larger scale, showing the device With certain parts, including aframe part, removed so as to show more clear'- m1y how,` the device may be mounted in position and electrical Yconnections made thereto;

Eig." 3is1a 'top plan view showing the construction With the gong broken away 'and with a frame part removed; f

Fig. l4 isla vertical transverse section as seen .along the line 4 of Figs. 3j and' l I v Fig. 5 is a bottom plan view as seenfrom the bottom in Fig. 4, with certain parts broken away;

is a'central vertical sectional View on a larger scale as seen along the linje i-S of Figs. 3 and l; and

Fig'. '7 isa fragmentary or detached sectional View as seen along the line 1-1 of Fig. 6.

' Similar reference characters refer to similar partsthfroughout the several views of the drawing.

Referring rst to Figs. 4, 5 and 6, I` provide a trame element It, which is preferably round where'the'gong or bell element Il is round; it is preferably ofV sheet metal and has a reinforcing `-side Harige' l?, the edge of which can rest against the 'Wall' or surface to which the device is to be secured, Yand it is preferably of a diameter greater thanthat ofthe gong H sov as to provide a marvginal area, generally indicated at A in Figs. 2 and '3ft/nien is' annular While the frame w and the gong il' are circular. Within the marginal area A oithe' frame |0- are positioned and; located certain parts later described in detail andr includ'- ing SlOt I3 Which is given the shape of an inverted T, in the vertical leg portion of which may vbe accommodated'. the shank of a securing screw Underneath the gong element i l I provide suitable means for supporting it from the frame lil and' also, suitable electro-magnetic actuating mechanism, the latter preferably comprising an Aelectroirnagnet is having 'a Windingv 20. anda core 27.1Y (Fig. c), In the embodiment. shown. the Velectro-magnet IQ is preferably positioned considerabiy to oneiside. of the center and! underhe gong ligand particularly Where'it is net I9 as a whole, smaller, and in this connec- 5 tion I may employ the gong supporting means and also certain parts uniquely coactingtherewith and with the vibratable armature, which is generally indicated by the referenceVv character 22.

The supporting means preferably comprises a A10 frame 23, conveniently in the form of a, sheetmetal stamping and preferably madeV ofa magi-f netic material such as iron or steel.V It has a horizontal portion that is stepped, principally Y because of the shape of the gong Il, toY providea part 24 of higher elevation than the other part 25; to the higher part 24 the gong His secured', f

preferably in a manner to permit the gong .to be manually given a rotary movement or displacement. Thus I may employ a screw 26 pass- 20 ing through a central hole in the gong AIl and threaded in the supporting part 24, andV where greater permanency of assembly is desired, the screw may fit very tightly into the threaded hole of the part 24 or its shank, after assembly, may 25 be radially expanded or partially headed over t0 give the effect of a rivet. Such permanency of mounting may-be had particularly where, as in the present invention, access to parts underneath the gong, for adjustment or the like, need not be had by removal of the gong, and thus also consistency of musical action of the gong may be better assured. Though the fastening may thus be made substantially permanent, neverthe- Y less it is preferably of Vsuch a character as to permit the gong il to be manually grasped and turned somewhat about its axis and to be frictionally held in the position to which it is thus turned; this action may be aided by the use of a spring washer 21, which is preferably shaped '4o Vsubstantially as shown in Fig. 6 and preferably has a sufficient radial extent to overlie and thus cover an arcuate slot 28 (see also Fig. 2) provided in the top wall of the gong YIl near its center.

The horizontal portion 24-25 of the frame 23 has opposed and preferably parallel, vertical or upstanding arms or parts 3l) and 3l, or the part 30 is preferably cut out, as at 30B, to provide transversely spaced end legs 3l)b and 3IJc (Fig. 4) 50 which are secured to the frame l0 in any suitable way, as by ears 3l)d and 30e whichv pass through suitable holes in the frame l0 and which are bent over against the underside thereof, as shown in Fig. 5. The opposed vertical part"3'l 55 is also shaped to provide transversely spaced legs 31h and Sic, which terminate'in lugs or ears 3|d and 3le which pass through holes in the frame I0 and are bent over against the underside thereof. In the case of the part 3l, the transversely 60 spacedr legs 311 and 31 are formed by vertically slitting and bending a substantial portion of the sheet metal outwardly (to the right in Fig. 6) to form a laterally and horizontally projecting bracket 3la Iwhich may, if desired, be stepped, 65

as is better shown in Fig. 6. The bracket 31a is of substantial width, and hence of substantial cross-section, and it extends into overlapping relation to the annular area A (Fig. 2) of the base frame l0. bracket part 3la may thus extend beyond and underneath the side 4wall portion Il of the gong Bracket 3lEL forms the support or mounting for the armature 22 (Figs. 6 and 5), preferably by 75 As Vis better shown in Fig. 6, the

form part of the magnetic circuit or circuits of' the electro-magnet, I may 4in this manner, and

vas isbetter shown in Fig. 6, bring the right hand end ofthe armature 22 into 'close proximity to the bracket Sla, thus diminishing the magnetic reluctance of the flux paths that make it possible I to utilize avery small air gap which, however,

is bridged by the flat spring 32 which can be of magnetic material. The bracket 3W, moreover,

provides a mounting for the armature that is Yconsiderably displaced to one side of the vertical axis of the gong- Il and thus, by providing the left-hand end of the armature 22 with a striker arm 35 and a, gong striker 36 which is juxtaposed toa diametrically opposed portion of the side wall IlaV of the gong l i, I am enabled to give the resiliently or spring-mountedarmature and striker structure a very considerable length, thus insuring an efficient whipping action thereof for producing the musical note of the gong when the armature and striker structure are set into vibration by the electro-magnetic mechanism. The striker arm 35 and a striker 36 may be formed integral or in one piece with the armature 22, as by a suitable stamping or punchpress operation. y Y l The right-hand end of the armature 22 thus extends between the rather widely lspaced legs 3|b and 3|c of the frame part 3|, and the lefthand portion of the structure extends between the spaced legs 30b and 30C of the opposed frame part 30, the armature structure lying above the plane of the wall llia of the frame l0. The armature 22 is thus held substantially lparallel to the horizontal part 25 of the frame 23, and with that arrangement the electro-magnet I9 is mounted, preferably to the part 25, so as to support the core 2l vertically and with its lower end juxtaposed to the armature 22. To mount the electro- 5 magnet, the core 2| may be provided with a reduced end portion Zia that extends through a rbetween the'core and the frame.

The armature mounting springY 32 has an extension 32a (Fig. 6) which can be of considerable or appropriate length, due to the structural features of the armature and its mounting asn above described, and at its end has a contact element 32b of a suitable alloy resistive to sparking action. `With Vthe mounting spring 32 normally holding the armature 22 spaced from the end ofthe core 2l, the spring contact 32a engages a contact element 33 (see also Fig. '7)V that is carried by part 352L ofa stepped bracket 39 (see Figf), part 39% being accommodatedgin some of the space provided by a large rectangular hole H31 provided in the top wall Iof the base li), whereby the part 39a may extend below the plane ofthe wall 10a; the other part 39h of the bracket 39 overlies the wall IllEL and is insulated'there-from by two sheets 4| and 42 of insulating material which extends radially outwardly (see Fig. 3) to the periphery of the base frame l0 so they may also serve to insulate thebinding post I5 from the frame. Part'39b (Figs. 7 and 3) is provided with ears 39c and 39d by which the frame-39 is clamped to the insulating plates 4I, 42, and at the outer end of the latter there is similarly clamped thereto a connector 'plate 43 by Vearsfia and 43B, connector pla-te 43 havingl a threaded hole therein for supporting the binding screw l5 when one of the external circuit wires is connected thereto. Between the two insulating plates 4l and 42 extends a wire44, which may be bare and whichk at its end is snaked through ythe hole through which one of the just-mentioned clamping ears extends, so as to bring the end of the wire underneaththe connector plate 43; the.

together as a si-ngle or enti-tywhichl may be separatelyY assemble-d and, as a'uni-t, put into position and assembled to the base I0. The latter `is provided with suitable holes IIIIc and Il)e (Fig.

5) to accommodate the `bent-over ears 379d `and 3!!c and thus prevent the latter from contacting `the base I0, portions of the sheet metal forming these holes being shaped` to provide ears Illf and Ig (Fig. 3) which pass upwardly through suitable holes in the insulating sheets 4l and 42 and are bent over to clamp the unit against the upper face ofthe frame Il). The unit is thus secured adjacent its inner end; at its outer end it is secured by ears Ih and II)k formed out of some of the metal that is struck out to form a hole |61 (Fig. 5) that underlies the ears 4.3%and 43h of the shank `of the binding screw I5so that these parts do not .contact the base I0.

With the insulating unit comprising the plates 4.!-42 thusassembled to the base I3, the' pigtail insulated lead wires k 23h-w208L projecting from the electro-magnet I9 may now be soldered respectively to the. wire 44 and tothe part 39b (see Figs. 7 and 3) and thus circuit of the winding 26 is completed to the bind-ing screws I5., and I6, through the interrupter formed bythe spring .part 322L and the part 39a of Figs. 7 and 6. More specifically, the circuit may be traced as follows:

From insulated binding screw I5, insulated wire 44, pigtail h, winding 2Q, pigtail, 20% interrupter contact part 39 and thence tothe spring 32BJ which is grounded to the frame 3, which lis in turn grounded by its mechanical connection to the base I0 in the annular portion A of which (see Figs. 3 and 5) the binding screwY I6 is threaded and likewise grounded thereto.

When electrical energy is supplied to this circuit, the electro-magnet I9 isenergized. togattract the armature 22 upwardly (Fig. `6) and whips the striker 36 upwardly to strike the gong II at" an appropriate point, which Vconveniently isa peripheral edge .portion of the depending side wall IIa of the gong I I, the upward movementy of the armature 22 interrupting the energizaticn of the winding 20 at the -contacts 32b and 38, whence the spring 32 whips the armature .and striker downwardly again to close the energizing circuit at the interrupter contacts, the processv .being repeated to .rapidly vibrate the. striker structure for so long as the energizingv circuit external to the joining'screws I'5 and I6 is maintained closed.

` As a result, the Vbell rings; however, it may be preferred to have the device function as a buzzer. instead of emitting a musical nota, and to convert its action'to buzzer action 1 makeipro- Y' vision for permitting 'the above-described `vibrat- .lLng 7action.'o the armature and striker tatalse "place,'but without setting the gong V"I Iinto soundconveniently in the form of a heavy sheet-metal stamping andv may be constructed of steel, particularly where itis desired that it coact in the magnetic circuit of the device, and conveniently iscarried by the vertical part 30 of the frame 23, against'the upper part of which it rests flatwise and to whichiit is'pivotally connected as by an eyelet 41 that passes through suitable registering holes, and is headed over as indicated in Fig. 6. This pivotal support is preferably close to the upper end of the lever part 46, which has an upward extention 46a to form a short lever arm that projects above the horizontal part 24 of the frame 23, and is shaped to project into the arcuate slot or hole 28 (see Figs. 2, 4 and 6) provided in the gong II and covered over by the spring Washer v2'I as above described. Accordingly a relatively small rotary movement of the gong II about its vertical axis as seen in Fig. 4 is ef,- fective, through the driving connection formed by the lever part 46a and the hole 23 in the gong, to swing the lever 46 about its horizontal axis and give the lower end of the long lever arm 46h (Fig. 4) a multiplied swing or movement a plane that intersects the striker arm 35. The lower and longer lever arm 46b is providedv witha horizontal open-ended slot 46C, preferably tapered or progressively enlarged at its open end (see Fig. 4), the internal portions of the slot 46 being of a vertical dimension appropriately related to the thickness of the striker 35 and to the stroke of its vibrating movements, asis later described.

Suitable stop means are provided to limit the range of swinging movement of the lever 46., and these may comprise lateral extensions or arms 46e and 46f (Fig. 4) bent over at their ends to provide stops 46g and 46h adapted for alternate coaction with the side edges of the vertical frame part 30, and they thus also limit the extent of rotary movement which may be manually given to the gong II.

If the gong II is swung in clockwise direction as viewed in Fig. 2, it swings the lever 46 into the position shown in Fig. 4, step 46g engaging the frame part 30. The frictional resistance provided by the pivotal mounting of the gong Il, and this may be aided by the frictional `resistance offered also by the pivotal mounting of the lever arm 46 itself, holds the parts in these respective positions, the lower end of lever 46 being thus held laterally displaced (Fig. 4) from the path of up and down vibrating movement of .the striker arm 35 and the latter is free to .be rapidly whipped up and down to repeatedly strike the gong I I and cause it to emit its musical tone.

If, however, the gong II is turned in counterclockwise direction in Fig. 2, the lever '416,is swung in clockwise direction in Fig.4A to thev extent permitted by the engagement of stop 46h with the frame part 30, and in that position of the change-over lever 46 the striker arm 36, entered through Ythe diverging mouth of theV slot 46c, becomes restricted in its moving strokes 'during vibration, the lower horizontal wall of the slot 46c just underlying the striker arm 35 (see Fig. 6) Apreferably without engaging the arm, 35 and thereby restrictingthe stress with rwhichthe spring 32 presses` the contact 32b into engagement with the contact '38, the upper horizontal wall orredge of the slot 46 becomes positioned at a height so that the upward strokes of the striker arm 35 are suicient in length to interrupt the energizing circuit at the contacts 32b and 38, but are shortened so that the striker 36 does not impact the rim of the gong II. The vibration and whipping of the striker arm 35, with its length of stroke thus restricted, results, however, in the striker arm 35 repeatedly or in rapid succession striking against the upper and lower horizontal walls of the slot 46C, emitting a buzzing noise from the resultant action and impacts of the parts. Fig. 6 shows the parts positioned for the just-described buzzer action, whereas in Figs. 2-5 the parts are shown positioned for bell-action; as better appears in Figs. 2 and 3, the lower edge of the side wall IIa of the gong II is cut away, as at I Ic, throughout a short portion of the depending peripheral edge, forming in eiiect a recess or slot in the lower edge of the gong. This recess I Ic is so positioned in relation to the arcu- I ate slot 28 in the gong I I that, upon turning the gong to set the change-over device 46 for buzzer action, the recess I Ic is moved into position above the striker head 36 (see Fig. 6) to better make sure that as the striker 36 is whipped up and down during buzzer action, any springiness in the striker arm 35 or its mounting will not permit the striker 36 from actually striking the gong II.

Whipping action is highly desirable for ringing the gong, and the elongated armature structure and its laterally displacedmounting, even though g many of the structural parts are compacted to be accommodated underneath a very small gong, bring about excellent whipping action during vibration and in order to give such action freer play, the plate portion Iiia oi the frame I (Fig. 6), in line with the elongated wide slot Ib, is displaced at Ille underneath and along the line of the striker 33 and its arm 35, thus giving the striker 36 more range of downward movement during vibration and thus enhancing the whipping action. The depressed portion IIIe (Figs. 3, 5, and 6) is preferably curved in the transverse cross-section, providing an upwardly concaved space (Figs. 3 and 6) into which the striker 3S may swing, and to cover over the slot I6b (Figs. and 6) so as not to downwardly expose the interrupter and armature parts, I provide two opposed pair of ears 49-46 and 50-50 (Fig. 5) which are struck downwardly (upwardly in Fig. 5) out of the frame plate I6al at acute angles to the plane of the plate |63, and into the opposed pairs of angles is inserted a sheet 5I of insulating material such as hard iiber, the sheet being manually iieXed or curved to get it into position, whence its tendency to straighten out maintains its opposed edges seated in the above-mentioned angles. Thus the sheet or cover 5I is detachably held in closing position and may be easily removed for access to parts thereunder.

Upon completion of assembly of the abovedescribed parts, an annular sheet-metal and preferably ornamental frame ring 52 (Figs. 6, 4 and l) completes the assembly, the ring 52 comprising a cylindrical side wall 52gv which telescopically interi-lts with the ange I2 of the base I0 and may be detachably interlocked therewith by providing the parts 522l and I2 with suitable intertting internal and external beads, as at I2B and 521, so. as to releasably spring or snap the parts together for holding them assembled or to `spring them apart for disassembly. The frame ring 52 has an upper annular wall portion 52c which overlies the annular area A (see Figs. 2 and 3) of the base plate IU and thus covers over the parts that are accommodated in that annular area A. The annular portion 52c (Figs. 4 and 6) may be given any desired ornamental conguration, and it terminates with its inner periphery closely spaced about the gong side wall I I somewhat above the lower edge of the latter. As indicated in Fig.. 1, the resultant structure would appear to comprise onlythe gong I I and the frame ring 52 and their concentric relationship Vand their respective congurations with the structure in neat and compact appearance.

In the annular portion A of the frame plate I0al I provide an aperture Il)k (Figs. 3 and 6) which underlies the right-hand end portion of the armature mounting, particularly the part 3IEL which is bent out of the vertical frame part 3I of the frame 23, and in the part 3|a I provide a transverse slot 3 Ik dimensioned to receive therein a tool such as an average-sized screw-driver. Such a tool may be inserted from underneath into the slot 3lk by passing it through the aperture Ik, or it may be inserted from above if the frame ring 52 is iirst removed. In either case, by using the screw-driver as a lever, the arm part 3la may be bent to set it at such an angle to the frame part 3I as will in turn properly position the armature 22 and striker arm 35 in relation to the parts with which they respectively coact, particularly with respect to the slot 46C in the change-over lever 146, so "as to insure proper buzzer coaction between the walls of the slot I6c and the striker arm 35 and to insure the desired bell action of the striker 36 upon the gong. Slot 3Ik may thus be employed during assembly and testing, or even for adjustment of the device after installation. If necessary, the insulating cover plate 5I may be removed to gain access to the arm 36a that carries one of the interrupter contacts, so that the arm 32a may be adjusted by bending to obtain the desired interrupter action for the setting given to the armature and striker.

If the change-over device 45 is made of a magnetic material, it can take part in forming part of the magnetic circut of the electro-magnet, the principal flux path comprising the core 2I (Fig.6) the right-hand part of frame part 25, frame part 3l, arm ZIE, and the armature 22; while another path comprises the core 2I, frame part 24, change-over lever 46, striker arm 35, and armature 22. With the device 46 set for bell action as in Fig. 4, a substantial air gap is interposed between it and the striker arm 35, diminishing the effect of the second-mentioned iiux circuit, and with the rst flux circuit then essentially eiiective, the whipping action of the armature and striker structure is enhanced. When the device 66 is set for buzzer action, during which whipping action isless material, the lower hookshaped portion of the lever 46 is brought into enveloping relation to` the striker arm 35, the air gap is diminished, and the second abovementioned flux path, with the air gap varying as the striker arm 35 vibrates between the upper and lower horizontal walls of the slot 66, can coact to increase the intensity of the impacts of the striker arm 35 against the walls of the slot and thus enhanceV the intensity of the buzzer action. Y

It will thus'be seen that there has been provided in this Vinvention a construction in which the various objects above mentioned, together with many thoroughly practical advantages, are successively achieved. It will be seen that the construction is of a thoroughly practical character, is of eicient and reliable action, and is compact and ornamental in appearance.

As many possible embodiments may be made of Y the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth, or shown in the accompanyingl drawing, is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. In a signalling construction, in combination, a sheet-metal frame carrying an electro-magnet and having an arm-like extension that is bendable relative to the rest of the frame, said extension having secured thereto a fiat spring element carrying an armature element for coaJction with said electro-magnet, signalling means responsive to actuation of said armature, and means forming an enclosure for said electromagnet and said arm-like extension, said frame extension having means engageable by a tool for bending it relative to the rest of the frame and thereby to fix the relationship between the armature element and said electro-magnet and said enclosure means having aperture means -through which said tool may be introduced and engaged with said frame extension.

2. In a signalling construction, in combination, an electro-magnetic element and a coacting armature element, means forming a mounting and enclosure therefor, and signalling means responsive to actuation of said armature element, said armature element having means mounting it for movement relative to said electro-magnetic element including a bendable bracket-like part which, upon being bent, alters the coacting relationship between said two elements, said bracket-like part having a hole therein for the reception of a lever-like tool such as a screwdriver for bending said part, and said enclosure means having aperture means through which to pass the tool for insertion into said hole.

3, A signalling construction comprising means forming an enclosure and having therein an electro-magnet and an armature element for coac- 10 tion therewith with means for supporting said electro-magnet, said armature element being supported in operative relation to said electromagnet by a bendable member which has a hole therein for the reception of a tool for bending said support member and thereby affect the coacting relationship between the armature element and the electro-magnet, said enclosure means providing a passageway for the entry of said tool into the hole in said bendable support member, and signalling means responsive to actuation of said armature element.

4. A signalling constructionr comprising an electro-magnet having an armature, signalling means responsive to actuation of said armature, support means for said electro-magnet, an armature-carrying element connected to said support means to position said armature in operative relation to said electro-magnet, the portion of said electro-magnet support means to which said .armature-carrying element is connected being movable to adjust the position of said armaturecarrying element and thereby change the position of said armature relative to said electromagnet, said armature-carrying element having an aperture therein to receive a tool adapted to effect change of position of said armature-carrying element, and means forming an enclosure for said electro-magnet and said armature support means and said armature-carrying element, said enclosure means having aperture means in a wall thereof juxtaposed to said aperture in said electronmagnet support means for the passage therethrough of a tool adapted to be received in said aperture to adjust the position of said armature-carrying element.


REFERENCES CITED The following references are oi record in the le of this patent:


Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1729284 *Jul 16, 1926Sep 24, 1929North East Electric CoElectromagnetic horn
US1804195 *Aug 25, 1926May 5, 1931Butler AmesElectric signaling apparatus
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3696410 *Feb 17, 1971Oct 3, 1972Long Raymond WHorn with buzzer
U.S. Classification340/397.1, D10/118
International ClassificationG10K9/00, G10K9/15, G10K1/00, G10K1/063
Cooperative ClassificationG10K1/063, G10K9/15
European ClassificationG10K9/15, G10K1/063