US2465111A - Audible electric signaling apparatus - Google Patents

Description

March 22, 1949. c. MILLER AUDIBLE ELECTRIC SIGNALING APPARATUS Filed Dec.

@q 32 INVENTOR CMe/sr/A/v ffmzfie ATT Patented Mar. 22 1949 AUDIEILE ELECTRIC SIGNALING APPARATUS Christian -Miller, Norwalk, Gonna, assignor to E6- OFFICE wards and @ompany, 51nd, Norwallk, Conn, a corporation of New York Application December 21, 1945,'Serial No. 636,479

8 Claims.

This invention relates to audible electric signalling mechanisms, and more particularly to electrically-actuated bells and buzzers.

One of the objects of this invention is to provide a compact, strong, durable, and inexpensive construction of the above-mentioned character. Another object is to provide an electricallyactuated audible signalling device that will be of reliable action and well adaptedfor-manufacture and installation. Another object is to provide a device of the above-mentioned character in which the actuating mechanisms will bedependably 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-responsive coacting parts such as an armature to achieve the desired signalling action of the device. Another object is to'carry out the last-mentioned object in a manner to facilitate such adjustment either during manufacture and assembly or after installation of the device. device so constructed that it may be readily and easily set for selection of one of several diiierent kinds of audible signals, such 'as musical or belllike signals and buzzer-like signals. Another'object is to provide a combined [bell and buzzer construction in which selection of either bell or buzzer action may be achieved in a simple and dependable manner. Another object is to provide a bell and buzzer construction in which the operating mechanisms are efiiciently housed within a bell-shaped or gong-shaped sounding element, yet so constructed that the mechanism be selectively set for either bell action or buzzer action. Another object is in general to provide an improved bell or buzzer construction, and other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts as will be exemplified in the structure to be hereinafter described and the scope of the application of which will be indicated in the following claims.

th accompanying drawing, in which is shown illustratively a preferred form of the varione possible embodiments of my invention,

Fig. 1 is .a top or plan view, on a small scale, of the complete device as it appears when installed;

Fig. 2 is a top plan view, on a larger scale,

Another object is to provide a signalling fill) showing the device with certain parts, including a-frame part, removed so as to show more clearly how the device may 'be mounted in position and electrical connections madethereto;

Fig. 3 is a top plan view showing the construction with the gong broken away and with a frame part removed; a

Fig. '4 is a vertical transverse section as seen along theline 4-4 of Figs. 3'and 1';

Fig. 5 is a bottom plan view as seen from the bottom in Fig. 4, with certain parts broken away;

Fig. 6 is a central vertical sectional view on a larger scale as-seen along the line =EE of Figs. 3 and 1; and

Fig. '7 is "a fragmentary or detached sectional view as seen along the line l"'l of Fig. 6.

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

Referring first to Figs. 4, 5, and 6, I provide a frame element ill, which is preferably round where the gong or bell element 1 I is round; it is preferably of sheet metal and has a reinforcing s-ide flange W2, the edge of which can rest against the wall or surface to which the device is to besecured, and it is preferably of a diameter greater than that of the gong ll so as to provide a marginal area, generally indicated at A in Figs. 2 and 3, which is annular where the frame 10 and the gong H are circular. Within the marginal area -A of the frame ID are positioned andlocated certainparts later described in detail and including slot 13 which is given the shape -of an inverted T, in the vertical leg portion of which may be accommodated theshank of a securingscrew l4 and through-the'horizontal portion o'fwhich (see Fig. 2') the electrical conductors may "be passed for connection to the binding " posts 15 and 16 insuch cases where the wiring is concealed and underlies the frame Ill. Diametrically opposed from the slot i3 is a hole I in the marginal portion A to receive another fastening device, such as a screw it (Figs. '3 and 2') Underneath the gong element 1| I provide suitable means for supportingit from theframe i9 and also suitable electro-magnetic actuating mechanism, the latter preferably comprising an electro-m'agnet 19 having a winding 26 and a core 2! (Fig. 6). In the embodiment shown the electro-magnet 195s preferably positioned considerably to one side of the center and underneath the gong H, and particularly where it is desired to achieve greater diminutiveness of construction I am enabled to arrange "the core 21 in relation to a magnetic circuit or circuits,

making it possible to make winding 20 and hence magnet I9 as a whole, smaller, and in this connection I may employ the gong supporting means and also certain parts uniquely coacting therewith and with the vibratable armature, which is generally indicated by the reference character 22. The supporting means preferably comprises a frame 23, conveniently in the form of a sheetmetal stamping and preferably made of a magnetic material such as iron or steel. It has a horizontal portion that is stepped, principally because of the shape of the gong I I, to provide a part 24 of higher elevation than the other part 25; to the higher part 24 the gong II is secured, preferably in a manner to permit the gong to be manually given a rotary movement or displacement. Thus I may employ a screw 26 passing through a central hole in the gong II and threaded in the supporting part 24, and 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 be radially expanded or partially headed over to 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, nevertheless it is preferably of such a character as to permit the gong I I 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 substantially 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 I I near its center.

The horizontal portion 2425 of the frame 23 has opposed and preferably parallel, vertical or upstanding arms or parts 30 and 3I, or the part 30 is preferably cut out, as at 33 to provide transversely spaced end legs 35' and 30 (Fig. 4) which are secured to the frame I in any suitable way, as by ears 33 and 33 which pass through suitable holes in the frame I0 and which are bent over against the underside thereof, as shown in Fig. 5. The opposed vertical part M is also shaped to provide transversely spaced legs 3I and 3|, which terminate in lugs or ears 3| and 3| which pass through holes in the frame I0 and are bent over against the underside thereof. In the case of the part 3I, the transversely spaced legs 3I and 3| 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 3I which may, if desired, h stepped, as is better shown in Fig. 6. The bracket 3W 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 I0. As is better shown in Fig. 6, the bracket part 3I=- may thus extend beyond and underneath the side wall portion II of the gong II.

Bracket 3I forms the support or mounting for the armature 22 (Fig. 6 and preferably by way of a, flat leaf spring 32 which is riveted flatwise against the underside of the bracket 3|, as by rivets 33, and has the right-hand end of the armature 22 secured thereto, as by rivets 34 (Fi 6). Where it is desired to have the bracket 3N form part of the magnetic circuit or circuits of the electromagnet, I may in this manner, and is better shown in Fig, 6, bring the right-hand end of the armature 22 into close proximity to the bracket 3I thus diminishing the magnetic reluctance of the flux paths that make it possible to utilize a very small air gap which, however, is bridged by the flat spring 32 which can be of magnetic material. The bracket 3I moreover, provides a mounting for the armature that is considerably displaced to one side of the vertical axis of the gong II and thus, by providing the left-hand end of the armature 22 with a striker arm 35 and a gong striker 36 which is juxaposed to a diametrically opposed portion of the side wall II of the gong II, I am enabled to give the resiliently or spring-mounted armature 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 striker 36 may be formed integral or in one piece with the armature 22, as by a suitable stamping or punch-press operation.

The right-hand end of the armature 22 thus extends between the rather widely spaced legs 3| and 3| of the frame part 3|, and the lefthand portion of the structure extends between the spaced legs 30 and 30 of the opposed frame part 39, thearmature structure lying above the plane of the wall I ll of the frame Ill. The armature 22 is thus held substantially parallel 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 2| vertically and with its lower end juxtaposed to the armature 22. To mount the electro-magnet, the core 2| may be provided with a reduced end portion 2| that extends through a hole in the frame part 25 and is headed over as shown, thus forming a good magnetic connection between the core and the frame.

The armature mounting spring 32 has an extension 32 (Fig. 6) which can be of considerable or appropriate length, due to the structural features of the armature and its mounting as above described, and at its end has a contact element 32 of a suitable alloy resistive to sparking action. With the mounting spring 32 normally holding the armature 22 spaced from the end of the core 2 I, the spring contact 32 engages a contact element 38 (see also Fi 7) that is carried by part 39 of a stepped bracket 39 (see Fig. 7) part 39 being accommodated in some of the space provided by a large rectangular hole Ill provided in the top wall I0 of the base I0, whereby the part 39 may extend below the plane of the wall Ill; the other part 39 of the bracket 39 overlies the wall I ll and is insulated therefrom by two sheets 4| and 42 of insulating material which extend radially outwardly (see Fig. 3) to the periphery of the base frame I0 so they may also serve to insulate the binding post I5 from the frame. Part 39 (Figs. 7 and 3) is provided with ears 39 and 39 by which the frame 39 is clamped to the insulating plates 4|, 42, and at the outer end of the latter there is similarly clamped thereto a connector plate 43 by ears 43 and 43 connector plate 43 having a threaded hole therein for supporting the binding screw I5 when one of the external circuit wires is connected thereto. Between the two insulating plates 4I and 42 extends a wire 44, which may be'bare and which at one of the just-mentioned clamping ears extends, so as to bring the end of the wire underneath the connector plate 43; the other end of the wire M can emerge from inbetween the insulating plates 4lt2 at any suitable point, as through a hole in the upper plate at (see Figs. 3 and '7) to expose it for making connection to the winding 20. The clamping action of the ears of the .parts 23 and 39 thus not only completes the electrical contact with the end of the wire, but also holds all of these parts together as a single unit or entity which may be separately assembled and, as a unit, put into position and assembled to the base it The latter is provided with suitable holes Hi and H3 (Fig. to accommodate the bentover ears 355 and 3m and thus prevent the latter from contacting the base to, portions of the sheet metal forming these holes being shaped to provide ears IN and lli (Fig. 3) which pass upwardly through suitable holes in the insulating sheets 41 and 42 and are bent over to clamp the unit against the upper face of the frame l b. The unit is thus secured adjacent its inner end; at its outer end it is secured by cars W and lil formed out of some of the metal that is struck out to form a hole I0 (Fig. 5) that underlies the ears #3 and 43 of the shank of the binding screw l5 so that these parts do not contact the base it.

With the insulating unit comprising the plates 4l42 thus assembled to the base ill, the pigtail insulated lead wires ZH' -Zil projecting from the velectro-magnet l9 may now be soldered respectively to the wire M and to the part 39 (see Figs. 7 and 3) and thus circuit of the winding 20 is completed to the binding screws and it, through the interrupter formed by the spring part 32 and the part 39* of Figs. 7 and 6. More specifically, the circuit may be traced as follows: From insulated -g screw i5, insulated wire pigtail winding 26, pigtail 28 interrupter contact part 39, and thence to the spring 32* which is grounded to the frame 23, which is in turn grounded by its mechanical connection to the base ill in the annular portion A of which (see Figs. 3 and 5) the binding screw it is threaded and likewise grounded thereto.

When electrical energy is supplied to this circuit, the electro-magnet i9 is energized to attract the armature 22 upwardly (Fig. 6) and whips the striker 36 upwardly to strike the gong ii at an appropriate point, which conveniently is a peripheral edge portion of the depending side wall l-l of the gong H, the upward movement of the armature 22 interrupting the energization of the winding 20 at the contacts 32" and 38, whence the spring 32 whips the armature and striker downwardly again to close the energizing circuit at the interrupter contacts, the process being repeated to rapidly vibrate the striker structure for so long as the energizing circuit external to the joining screws l5 and l 6 is maintained closed.

As a result, the bell rings; however, it may be preferred to have the device function as a buzzer instead of emitting a musical note, and to convert its action to buzzer action I provision for permitting the above-described vibrating action of the armature and striker to take place, but without setting the gong ll into sound-emitting vibration. A preferred manner of carrying out this provision comprises a controllable change-over device, preferably in the form of a lever, generally indicated by the reference character 46 and better shown in Figs. 4 and 6; it is conveniently in the form of a heavy sheet-metal stamping and may be constructed of steel, par;- ticularly Where it is desired that it coact in the magnetic circuit of the device, and conveniently is carried by the vertical part 33 of the frame 23, against the upper part of which it rests fiatwise and to which it is pivotally connected as by an eyelet 1H 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 58, which has an upward extention 35 to form a short lever arm that projects above the horizontal part :2-4 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 H and covered over by the spring washer 21 as above described. Accordingly a relatively small rotary movement of the gong l l about its vertical axis as seen in Fig. 4 is eiiective, through the driving connection formed by the lever part 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 4t (Fig. 4) a multiplied swing or movement in a plane that intersects the striker arm 35. The lower and longer lever arm 4t is provided with a horizontal open-ended slot Mi preferably tapered or progressively enlarged at its open end (see Fig. l), the internal portions of the slot 56 being of a vertical dimension appropriately related to the thickness of the striker 35 and to the stroke of its vibrating movements, as is later described.

Suitable stop means are provided to limit the range of swinging movement of the lever Q6, and these may comprise lateral extensions or arms 38 and 46 (Fig. i) bent over at their ends to provide stops 48 and @6 adapted for alternate ccaction with the side edges of the vertical frame part fill, and they thus also limit the extent of rotary movement which may be manually given to the gong l l If the gong H is swung in clockwise direction as viewed in Fig. 2, it swings the lever 46 into the position shown in Fig. 4, stop 46 engaging the frame part 30. The frictional resistance provided by the pivotal mounting of the gong H, and this may be aided by the frictional resistance offered also by the pivotal mounting of the lever arm ti; itself, holds the parts in these re spective positions, the lower end of lever 46 being thus held laterally displaced (Fig. l) 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 H and cause it to emit its musical tone.

If, however, the gong H is turned in counterclockwise direction in Fig. 2, the lever it is swung in clockwise direction in Fig. 4 to the extent permitted by the engagement of stop lii with the frame part 38, and in that position of the changeover lever 46 the striker arm 36, entered through the diverging mouth of the slot 46, becomes restricted in its moving strokes during vibration,

e the lower horizontal wall of the slot 46 just underlying the striker arm 35 (see Fig. 6) pref,- erably without engaging the arm 35 and'thereby, restricting the stress with which the spring 32 presses the contact 32* into engagement with the contact 38, the upper horizontal wall or edge of the slot 45 becomes positioned at a height so that the upward strokes of the striker arm 35 are sufficient in length to interrupt the energizing circuit at the contacts 32 and .38, but are shortened so that the striker 36 does not impact the rim of the gong l l 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 46, 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 N of the gong H is cut away, as at H, throughout a short portion of the depending peripheral edge, forming in effect a recess or slot in the lower edge of the gong. This recess H is so positioned in relation to the arcuate slot 28 in the gong H that, upon turning the gong to set the change-over device 46 for buzzer action, the recess H is moved into position above the striker head 35 (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 ll.

Whipping action is highly desirable for ringing the gong, and the elongated armature structure and its laterally displaced mounting, even though 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 W of the frame I!) (Fig. 6), in line with the elongated wide slot 10 is displaced at H) underneath and along the line of the striker 36 and its arm 35, thus giving the striker 36 more range of downward movement during vibration and thus enhancing the whip ping action. The depressed portion E (Figs. 3, 5, and 6) is preferably curved in transverse crosssection, providing an upwardly concaved space (Figs. 3 and 6) into which the striker 36 may swing, and to cover over the slot ifl (Figs. 5 and 6) so as not to downwardly expose the interrupter and armature parts, I provide two opposed pairs of ears l949 and 5fl50 (Fig. 5) which are struck downwardly (upwardly in Fig. 5) out of the frame plate ill at acute angles to the plane of the plate It, and into the opposed pairs of angles is inserted a sheet 5! of insulating material such as hard fiber, the sheet being manually flexed 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 5| 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 1) completes the assembly, the ring 52 comprising a cylindrical side wall 52 which telescopically interfits with the flange [2 of the base l0 and may be detachably interlocked therewith by providing the parts 52* and I2 with suitable interfitting internal and external beads, as at 12 and 52 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 52 which overlies the annular area A (see Figs. 2 and 3) of the base plate H] and thus covers over the parts that are accommodated in that annular area A. The annular portion 52 (Figs. 4 and 6) may be given any desired ornamental configuration, and it terminates with its inner periphery closely spaced about the gong side wall I l somewhat above the lower edge of the latter. As indicated in Fig. 1, the resultant structure would appear to comprise only the gong H and the frame ring 52 and their concentric relationship and their respective configurations with the structure in neat and compact appearance.

In the annular portion A of the frame plate II] I provide an aperture I3 (Figs. 3 and 6) which underlies the right-hand end portion of the armature mounting, particularly the part 3 l which is bent out of the vertical frame part 3| of the frame 23, and in the part 3P I provide a transverse slot 3 I dimensioned to receive therein a tool such as an average-sized screw-driver. Such a tool may be inserted from underneath into the slot 3| by passing it through the aperture I0 or it may be inserted from above if the frame ring 52 is first removed. In either case, by using the screw-driver as a lever, the arm part 3P may be bent to set it at such an angle to the frame part 3| 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 46 in the change-over lever 46, so as to insure proper buzzer coaction between the walls of the slot 46 and the striker arm 35 and to insure the desired bell action of the striker 36 upon the gong. Slot 31 may thus be employed during assembly and testing, or even for adjustment of the device after installation. If necessary, the insulating cover plate 5| may be removed to gain access to the arm 39 that carries one of the interrupter contacts, so that the arm 39* 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 circuit of the electro-magnet, the principal flux path comprising the core 2| (Fig. 6), the right-hand part of frame part 25, frame part 3!, arm 21 and the armature 22; while another path comprises the core 2|, frame part 24, change-over lever 46, striker arm 35, and armature 22. With the device t6 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 flux circuit, and with the first flux circuit then essen tially effective, the whipping action of the armature and striker structure is enhanced. When the device 46 is set for buzzer action, during which whipping action is less material, the lower hook-shaped 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 46, can coact to increase the intensity of the impacts of the striker arm 35 against the walls of the slot and thus enhance the intensity of the buzzer action.

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

As many possible embodiments may be made of 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 accompanying drawing, is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. A signalling construction comprising a gong, a frame having a pivotal support for said gong and carrying electro-responsive striker mechanism accommodated in the space underneath the gong and having a striker for striking the gong, a vibration-limiting stop movably carried by said frame and adapted in one position to limit the movement of the striker relative to said gong, said gong being coupled to said stop whereby movement of said pivotally-supported gong will move said stop into and out of said striker-limiting position.

2. A signalling construction comprising a gong, frame means having means movably supporting the gong, said frame carrying a striker and striker-actuating mechanism for giving the striker a path of movement to impact said gong, means movably carried by said frame means and provided with means for limiting its range of movement and having a part which is movable into or out of a position to intersect the path of gong-approaching movement of the striker, and means forming a mechanical connection between said movable means and said movable gong whereby the former may be moved by the latter and the range of movement of the gong thereby limited, said gong presenting a portion for coaction with said striker at one end of the range of gong movement for striking coaction therewith and having said portion moved out of striking coaction with said striker upon movement in a direction toward the other limit of its range of movement.

3. A bell and buzzer construction comprising a striker and an arm therefor, said arm having a spring mounting to effect whipping action, electro-magnetic means for actuating said arm, a gong, means mounting said gong in a first position to be struck by said striker to produce a musical note, said gong being movable to a second position substantially out of the path of said striker, and a stop coupled to said gong to be moved into the path of movement of said striker arm by said gong to be thereby adapted to emit a non-musical sound when struck by said striker.

4. A signalling construction comprising a base frame, an inverted U-shaped frame having its arms bifurcated, the ends of the bifurcations being secured to said base frame, a gong supported by said U-shaped frame and overlying both frames, an electro-magnet supported by said U-shaped frame, striker means having means mounting it for vibrating movement in a plane parallel to the axis of said gong and having a striker head underlying a peripheral portion of the gong, and armature means coacting with said electro-magnet for actuating said striker means.

5. A signalling construction as claimed in claim 1 in which said striker means extends along and through the spaces provided by the bifurcated arms, said mounting means for the striker means including a bracket-like frame extension substantially underlying a peripheral portion of the gong that is juxtaposed to said first-mentioned peripheral portion.

6. A signalling construction as claimed in claim 4 in which the arms of said U-shaped frame are bifurcated and said striker means extends along and through the spaces provided by the bifurcated arms, said mounting means for the striker means including a bracket-like frame extension substantially underlying a peripheral portion of the gong that is juxtaposed to said first-mentioned peripheral portion, said bracket-like extension comprising at least a portion of the metal of one of said arms bent out of its plane to bi-furcate it.

'7. A signalling construction as claimed in claim 4 in which said gong is of lesser lateral expanse than that of said base frame, at least a portion of the mounting means for said striker means extending laterally beyond the gong, and a housing element secured to said base frame and laterally enveloping the gong.

8. A signalling construction as claimed in claim 4 in which said gong is of lesser lateral expanse than that of said base frame, at least a portion of the mounting means for said striker means extending laterally beyond the gong, terminal means in the electrical connection with said electro-magnet and carried by said base frame in a portion thereof beyond the lateral expanse of said gong, and a housing element detachably secured to said base frame and overlying those portions, and the parts carried thereby, of the base frame that are beyond the lateral expanse of said gong.

CHRISTIAN MILLER.

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

UNITED STATES PATENTS Number Name Date 496,690 Kolbe May 2, 1893 833,741 Hansen Oct. 23, 1906 1,697,057 Edwards Jan. 1, 1929 1,831,037 800% Nov. 10, 1936 2,014,237 Miller Sept. 10, 1935 2,140,577 Gaynor Dec. 20, 1938 FOREIGN PATENTS Number Country Date 87,616 Austria Mar. 10. 1922

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