US923048A - Mechanically-actuated acoustic apparatus and method. - Google Patents

Description

M. R. HUTGHISON.

MBGHANIGALLY AGTUATED ACOUSTIC APPARATUS AND METHOD.

APPLIOATION FILED MAR.14, 190e.

923,048. Patented May 25, 1909.

2 SHEETS-SHEET 1.

M. R. HUTGHISON., MBGHANICALLY AGTUATED ACOUSTIC APPARATUS AND METHOD.

Patented May 25, 1909.

APPLICATION FILED MAR-14, 1906. 923,048.

` 2 SHEETS-SHEET 2.

PATENT o EEroE.`

MILLER REESE HUTCHISON, OF BRQNXVILLE, NEW YORK.

MECHANICALLY-ACTUATED ACOUSTIC APPARATUS AND METHOD.

l To all whom it mag/"concern: I

Be it known that I, MILLER REEsE HUTcnI- SON, acitizen of the United States, and a resident of BronXville, in the county of Westchester and State of New York, have inf vented certain new and useful Improvements in Mcchanically-Actuated Acoustic Apparatus and Methods, of which the following is a specification. A

'l`his'inventionrelates to signaling or alarm horns particularly such as are used onautomobiles, fire engines, launches, steam boats, y

light houses, factories, etc.

My object is to produce -a device of this type capable of utilizing as much power and of producing as loud a sound asmay be desired. Y

Another object is to obviate the necessiti.f

4:for refinements of construction and adjust;

ment usually found in devices of this class Vand also to insure reliable positive operation of the device, under all the eXigencies of practical every day use. p

^ In the accompanying illustration I have shown, more or less diagrammatically, 'sunf dry embodiments of niy invention.

'tration of a modification having different In this showings- Figure 1 is a view, partly in section and partly in elevation, of a complete acousticy apparatus under the present invention; Fig. 2 is a diagrammatic illusdrive means; Fig. 3 isa view oi an eccentrically mounted `pitman having a lost-motive manner connecting pitman and diaphragm; Fig. 8 shows still anotherv alternative connection; and Fig. 9 shows a-cam actuated diaphragm.

The 'invention may be embodied inmanj-. dierent speciiic forms but I usuallyprefcr to employ a horn 1 and some form of clase,

as 2, though any form oiresonantamplifier may be employed or may be omitted" alto gether, as may also the case 2.,v v These, parts .of the device may be oi any knniwnyorde-y 4.eccentric position by means of the sleeve 14 sired construction.

As shown in Fig. 1 the horn is screwed into n Specification of Letters Patent. Application filed. March 14, 1906. Serial No. 306,933

l shown-in Figs. 3, 4 and 5.

Patented May 25, 1909.

i a nipple 3 in an end closing cap screwed on to the case 2. The horn is secured by a set screw 5 and the end. closure 4 may be provided with any desired locking means. l

The vibrator for exciting the horn may be heldin any desired Way and may be a diaphragm 5, held b y suitable washers 6a, which may be clamped between the front end ofthe case 2 and the end closing cap 4.

The diaphragm is caused to execute its to and fro movements through a suitable mechanical connection, a preferred form of which is shown in Figs. 8, 4 and 5. As a source oi' power, I may utilize any reciprocating or rotary motor but preferably a rotary motor with a link and crank, or eccentric or other'device for changing rotary into reciprocating motion.

In Fig. 1 I have shown the link 6, mounted on the crank pin or eccentric 7, and connected to the diaphragm 5 through a pitman 8. The link 6 and the pitman 8 together form an articulated thrust member or element, rigid in the line of action. When this articulated thrust member is employed sbme form of guide such for instance as shown at 9 is'necessary. This is held in position by a suitable support 10, which may be formed as a tight partition. In any case the support may be adjustable, as shown, and in the case of a tight partition, this serves to vary the resonance space back of the diaphragm 5, so that it may operate as an adjustable resonator, in addition to. serving its function as guide for the pitman8.

The resonator partition is less necessary in my present device because I am able to apply greater power to the diaphragm and thus` make it less important in practice to have the refinements which .arev highly desirable in the arrangement oi less posif tively acting devices of this type. I may use a simple link connection between the eccentric and the vibratory diaphragm 5. as

movement necessary for vibration of diaphragm 5 is provided by the adjustable crank pin 7 carried by the head 11 adjustable vin groove 12 which is under cut as at 13 to' '..iitsaid head. The crank pin presents a .bearing surf-ace eccentric to the drive mem; baril. The crank is' clamped the desired the annular collar 16 of which engages the In such case the face of the rotary disk 15. It forced into clamping relation therewith by means of the nut 17, thus binding the head 11 against the under cut portion 13 of groove 12. The sleeve 14 serves as the journal for the link. The disk 15 may be rotated in any desired manner from any desired source of power. As shown in Fig. 1 it is supported in a suitable standard 17 Within the case 2 and is connected by a iexible shaft 18, with a friction wheel 19, adapted to engage the iiywheel or shaft or any other rotating part preferably rotated by the prime motor of the automobile or launch. Such rotating part is diagrammatically indicated at 20.

The friction Wheel 19 is arranged or constructed to have its movement controlled by the operator so that the diaphragm 5 may be vibrated and the horn lsounded at will. The friction wheel 19 may be mounted in a movable journal 21, for movement into and out of contact with 20. The journal 21 may be carried by a reciprocating member 22 slidably held in a guide 23 which may be in the form of a bushing secured by a nut 24 as shown. -A collar or other stop 25 may be employed to limit movement away from the driver and a s ring 26 may be provided for normally holding the arts in retracted position. A fixed brake s oe 27 may be arranged to bear upon 19 in the retracted posi tion to prevent prolonged dying away effect of the sound in the horn when the power is shut off. The reciprocating member 22 is provided with a head 28 arranged in a suitable position for control by the operator preferably in the floor 29 within reac of his foot.

In Fig. 2 I have shown another desirable means for causing and controlling the rotation of the disk 15 to agitate the diaphragm 5. In this arrangement the disk 15 is -mounted upon the shaft of an electric motor 30 which may be mounted within a case 2 (Fig. 1) in any suitable manner. The motor may be quite small and lconsume but little current and may have an operating voltage so low as to be readily supplied from the storage or other batteries used for igniting the engine or if desireda small generator drivenfrom any desired rotating point of the engine may be used as the source of power. Circuit leads 31, 32 connect the motor with any such source as, for instance, the battery indicated at 33 and there may be bridged thereacross any desired number of circuit closers 34, the closure of any of which will serve to start the motor and sound the horn. An adjustable impedance 35, may be ineluded in this circuit and mayl be either an inductive or an ohmic resistance or both and ma be designed and regulated either to limit the maximum normal operating current orto prevent too sudden and toogreat instantaneous current at starting or to accomplish both functions. This form of lthe same against shoulder 42.

' phragm member.

drive is more specifically shown, described and claimed in my application Serial No.

The reciprocating movement imparted to the link'or pitman 8, whether from one of the above described sources of power or from any other desired source, may be applied to the vibrating diaphragm in avariety of volving the exertion of considerable power` the wear on the diaphragm would be excessive, it is better to provide the diaphragm with a member to serve as a Wear piece in such engagement or impact. This member may be, and referably is, rigid with the diaphragm itself and participating in its movement. Such movements may be imparted by a lost motion connection, such as shown in Figs. 3 and 4, or by positive connection, such as shown in Fig. 6. In the present embodiment of my invention I refer the lost motion connection shown in igs. 3 and. 4. In said figures the diaphragm is provided with a member for engagement in such con. nection, this member consisting of an ear 40 provided with a screw shank 41 and formed with a shoulder 42' is rigidly secured to the center of the diaphragm by lock nuts 43, screwed down uponthe diaphragm, to clamp This ear is provided with a transverse pin 44 which plays in slots 45 in the bifurcated head 46 of the driving member, 6. This element 6 is a thrust member provided toward its outer end with rigid unyielding surfaces which engage With similar surfaces carried bythe dia- In the structure of Figs. 3 and 4, 6 is a thrust member in its outward movement and a tension member in its inward movement, and is the equivalent of the articulated thrust member formed by 6 and 8 in Fig. 1.

It is obovius that a mere reversal of this arrangement, either as to the slot and in or as to the bifurcation, would not invo veI departure from the spirit of my invention,

'but the arrangement shown has the advantage that it puts the greatest possible proportion ofV the weight and of thev wear on the driving member rather than on the diaphragm member, the male engaging memers being from the nature of things, less -massive in design for e ual strengths than the female members. 'l e pin 44 maybe easily renewed whereas a worn slot in 45 would require an entirely new part and unless made undesirably heavy the wear would be very rapid.

By reason of the comparatively large amount of power available the diaphragm may be made of relatively great diameter, stiffness. and amplitude of vibration. It may be clamped and may be put under buckling stress in one direction or it may be a plane sheet arranged to be normally free from such stress. With a 6 inch diaphragm the amplitude of vibration may be 1/32 to 3/32 of an inch. These figures are merely illustrative of one possible set of proportions. In practice Wide variations are possible.

'lhe lost motion connection' is preferably `.sed in connection with a diaphragm having only one normal position of rest, as for instance, a plane diaphragm )referably under nostress though 1t may e permanently buckled in one direction. rthe arrangement will be such that one .end of the slot will engage the pin 44 and forcibly displace the diaphragm in one` direction from its normal position, bringing it back again to normal,

then after a slight interval the other end of the slot will engage the pin 44 and forcibly displace -and restore the diaphragm from normal, in the opposite direction.

W ith the tight connection shown in Fig. 6,

a the movements of the diaphragm are forced and the crank throw and the amplitude of vibration of the diaphragm are equal. In certain cases a useful, though less efficient signal f this purpose.

or alarm, may be produced by so selecting i the area of the diaphragm and distribution of stresses thereupon that the forced movement at the center thereof will cause semiindependent elastic vibrations localized or distributed in zones about the rigidly sec-u1 d center and between it and the periphery. A large diaphragm, especially if thin or of less resilient material, is likely to vibrate in this way When the driver is operated at very high speeds, so as t-o force the main central portions of the diaphragm more rapidly than the movement can. be transmitted to the other vibratory portions more remote from l the center.

By applying power to the vibrating diaphragm mechanically in accordance with my present invention, I am enabled to select the material of such diaphragm with a view solely to securing the elastic qualities and acoustic properties most desirable in such a j the rotary driving member or by the reclpmember without reference to the electromagnetic qualities which must be considered Where the power's to be applied magnetically. I. may make the diaphragmof any desired diameter and thickness and of any de.- sired quality of elastic material, as, for instance, soft iron, spring steel, Wood, etc.

W here the material selected is sufficiently elastic and durable the pin connection 44'd (Fig. 6) may be dispensed with and connections such as shown in Figs. 7 and 8 maybe employed. In Fig. 7 link 6 is clamped directly to the diaphragm thus causing a certain amo-unt of angular lexure thereof. The

Fig. S' the annular flexure may be almost eny tirely avoided.

By sparing apart the engaging surfaces of the arrangements of-Figs. 7 and 8, a lost motion connection is produced which may be proportioned and utilized after the manner described for Vsuch connections with reference to Figs. 4 and 5., 'lhis spacing is not specifically shown as it may, and usually would, be too small to be shown without exaggeration. A mere loose fit of the diaphragm-engaging members is sufficient for In Fig. 9, I have shown the disk 15 formed with cam projections 54 arranged to engage a suitable surface 55 on the diaphragm 5, to forcibly displace the latter in one direction without the necessity of a separate reciprocating member. The use of cams in this ,Way permits of a lost motion engagement due to the abrupt radial faces on the back side of the cam, which permit the free elastic return of the diaphragm at its own natural rate'.

In practice the design and proportion of part-s may vary Widely from those shoyevn in the drawing and in making such variations it -will generally be advisable to avoid too great mass or Weight in the design of parts carried by the diaphragm and also of reciproca-.ting parts such as the link 6. If the speed of rotation is 'extremely high, the latter member if too heavy may have a serious pounding eflect in directions parallel both to the plane of the diaphragm 5 and to the plaire of the disk 15. This is further undesirable, in most cases, as tending to impart too much lateral component to the force eX- erted upon pin 44.

In operating any of the various forms of my invention, the rate or frequency of the movements forced upon the diaphragm by rocating driving member,'may be independent of the natural frequency of free vibration of the diaphragm, the diaphragm being` given a positive or forced drive, but great resonant sound eflectwith small expenditure of power will be attained Whenthe -forced movement and the natural movement are of the same frequency.

. lith the tight coupling of driving member and diaphragm such as shown in Figs. 6, 7 and 8, the weight or inertia of the reciprocating driver is in effect a load upon the diaphragm, at all speeds below that corresponding to the natural rate of vibration of the diaphragm, when free or unloaded. With a given ldiaphragm, as with any other elastic vibrator, the rate of vibration is dependent on the elasticity and on the mass of metal to be moved, or its inertia, and with the structure of Figs. 6, 7, and 8 where there is no play between the diaphragm and driver, when the parts are in a position of rest, the inertia of the diaphragm, or the opposition to vibration, is increased by an amount corresponding tothe mass of the driving parts since in order to move in vibration, the center of the diaphragm must take with it the attached arts of the driver. But where the driver is itself kept in reciprocating motion,

Y if the reciprocation corresponds to the natural frequency or rate of the diaphragm then the lat-ter behaves as if unloaded and free to move normally. At any lower rate of vibration, the driver constitutes a load. If the driver be speeded up sufficiently, this load will be taken off from the diaphragm in accordance with the increase of speed. The efficiency will therefore, in general, be greater where the speed of the driver is equal to the natural free period or rate of movement of the free diaphragm.v These considerations are of practical importance in con. nection with diaphragms having a natural fundamental rate of vibration corresponding to the lowermost audible notes because the use of a crank imposes practical limitations as to the rate of the forced impulses. The limit is higher in the case of a construction like that of Fig. 9 because the periphery of the disk 15 may be greatly increased and the number of cams 54 greatly multiplied, but in this case, the coupling is loose, and the rate of positive outward displacement of the diaphragm is necessarily limited by the time required for the elasticity of the diaphragm to bring it back into position to be again forced outwardly. In this case, also, the full swing of the diaphragm can only be attained where the cam contacts are separated by intervals sufficient to permit the diaphragm to effect its elastic return, and 'Where the cam contacts occur more frequently than the natural period of free elastic vibration of lthe diaphragm, the amplitude of the movement will be cut short. Hence, it will be understood that while the specific form of cam withan abrupt shoulder on the back side thereof will always permit a high velocity elastic return of the diaphragm, no matter how slow the outward movement may be, nevertheless, in this case also, the best result will be attained where the times and velocities of the cam forcing movements in one direction are harmonizedwith the times and velocities of the free elastic return.

In .the case of the loose link coupling shown in Figs. 3 and 4, the same principles apply. It will be obvious that the operation of this device may be very much the same as that of the cam, except that a forcing impulse may be applied once per revolution, either. on the outgoing thrust movement or on the incoming tension movement, or, if. desired, both the outgoing thrustvand the incoming tension impulses may be applied so that part of the movement in each direction is forced. In either case, the movement is partly forced and partly free, so that the best operation is obtainable by harmonizing the time and velocities of the forced 'part of the movement of the diaphragm with the natural times and velocities of the free part of the movement thereof.

the natural frequencies of the horn, so that Within limits, the natural frequencies of the diaphragm become the same as the natural frequency of the horn. This is of particular value in connection with a friction or electric motor drive where the speed is free to vary proportionally to the work done, since with suc motive power, the displacement tends to set itself in synchronism or harmony with one of the natural resonant frequencies of the device, so that in turning on or turnin off the motive power, the note tends to dwe at one natural frequency until the power increases toa point where it can jump to the next natural frequency.

The resonant qualities of the horn and the natural periodicities of the dia hragm may be harmonized by making the undamental or the prominent harmonic of the one correspond to a fundamental or a harmonic of the other.

In many cases it will be found sufficient to select a diaphragm of large diameter and force thereon a desired frequency independent of its natural period, the latter being suppressed. In such case the forced eriodicity may correspond to a fundamenta or a harmonic of the horn. If a prominent harmonic of the diaphragm be in accord with a natural period of the horn, the forced eriodicity may be arbitrarily, selected wit out' particular reference to the period of either the horn or the diaphragm.

The crank and link are specially adaptedv 92eme generating surface is substantially sinusoidal and particularly adapted for periodic movements in which elasticity and inertia are factors. Certain of my -claims herein are broad enough to cover the cam arrangement for vibrating the diaphragm as shown in Figi) and also the rotary electric motor drive exi plained in connection with Fig. 2 but the more specific claims hereof are directed to the crank and link arrangement for vibrating the diaphragm and to the friction drive shown in Fig. 1. The cam of Fig. 9 is ineluded illustratively as an alternative form in my application, Serial No. 373,946, but the specific claims therefor' are found only in my divisional application Serial No. 457,710, which said application also contains broad claims for the rotary electric motor driving arrangement shown in. Fig. 2 hereof.

I claim:`

1. In an alarm or signaling apparatus of the class described, a horn or resonator and a f diaphragm in combination with a shaft, a member presenting a bearing surface placed eccentrically of and rotated from said shaft, and a thrust member driven by said eccentric surface and arranged toforcibly displace said diaphragm in a direction normal to the surface thereof, together With high-speed means for rotating said shaft at a ratesufficient Ito produce a loud note, substantially as described. 2. In an alarm or signaling apparatus of the class described, a hornor resonator and a diaphragm having a member adapted for engagement in combination with a shaft, al

member presenting a bearing surface placed I eccentrically of and rotated from said shaft and a thrust. member engaging said eccentric Surface and adapted to cause positive engagement with and positive displacementbf said diaphragm member in one period of the motion of the diaphragm while permittingV free movement of such diaphragm in another period of said motion.

3. In an alarm ci signaling'device of the class described, a horn or resonator, a diaphragm, a rotary member and high-speedmeans forrotating said rotary member, in

combination with a body rigid in the line of.

'horn or resonator and a diaphragm therefor,

motion and ada ted to apply the power of said rotary mem er to adiaphragm element in such manner as to cause a positive displacement of the diaphragm in one period of motion and permit a free movement'in another, said parts being so relatively dimensioned, proportionedfand arranged asl to cause a plurality of rotations of said rotary member to be necessary' to cause anaudible note to bey emitted by the diaphragms 4. In-an alarm or signaling device of the class described, a horn or resonator, a diaphragm, a rotarymember and high-speed means for rotating said rotary member, in

combination with a body rigid in the line of motion and having a lost motion connection With a diaphragm element, said parts bein so relatively dimensioned, proportioned, an arranged as to cause a plurality of rotations lof said rotary member to ybe necessary to cause an audible note to be emit-ted by the diaphragm.

5. In an alarm or signal of the class described, a horn or resonator, a diaphragm and a rotary shaft arranged with its axisapproximately parallel to the diaphragm, in combination with means for applying the power of the shaft to vibrate the diaphragm, said means including a member eccentrically pivoted to the shaft for movement in a plane at right angles to the shaft and diaphragm, said means being provided toward its outer end with a hard and unyielding surface adapted to strike against an element of the diaphragm. V

6. In an alarm or signal of the class described, a horn or resonator, a diaphragm and a rotary shaft arranged with its axis approximately parallel to the diaphragm, in 90 combination with means for .applying the power of the shaft to vibrate the diaphragm, said means including a member secured to the shaft by means adapted to permit movement of said member eccentrically of the shaft axis in a lplane perpendicular to the shaft and diaphragm, said means bein formed toward its outer end with a hard an( unyielding surface adapted to strike against an element of the diaphragm.

7. In an alarm or signaling apparatus, a horn or resonator and an air vibrating member, in combination with a reciprocating driving member having a lost motion engagement therewith.

.8. In an alarm or signalin apparatus, an

air vibratin member, in com ination with a rotary mem er and a reciprocating vmember driven by the latter and having a lost motion connection with said air vibrating member.

9. In an alarm or signaling apparatus, a horn or resonator and a diaphragm therefor, in combination with an eccentric and pitman for forciblydisplacing the same in one direction and then in the other alternately.

10. In an alarm or signaling apparatus, a

in combination with a reciprocating driving member operatively connected therewith to forcibly move the same and to permit fur- 12o ther movement thereof by free elastic vibra-v i tion.

y11. In an alarm or signaling apparatus of the class described, a. horn orresonator and a diaphragm, in combination with a reciproeating member, provided with a rigid surface adapted to engagelthe diaphragm and means for reciprocatin said member at a rate harmonizing with t e rate of elastic vibration of the diaphragm.

12. In a signaling apparatus for motori conveyances, a horn and a diaphragm closure therefor in combination With a reciprocating member having a lost motion connection With the diaphragm, a rotary member imparting power to said reciprocating member and -rotary driving means for said rotary member adapted to derive power from the moving parts of a' motor vehicle.

13. In a signaling apparatus for motor conveyances, a horn and a diaphragm closure therefor, said diaphragm carrying a Wear piece rigidly secured thereto, in combination with the motor apparatus of said vehicle and a reciprocating member energized from the latter and having a lost motion engagement with said'vvear piece in the diaphragm.

14. In an alarm or signaling apparatus of the class described, a diaphragm in combination with a rotary member having an eccentric thrust element, a thrust member driven by said eccentric element and having a rigid surface adapted for loose engagement with a diaphragm element to forcibly' displace the same in' a direction normal to the surface thereof While ermtting free elastic movement beyond t e forced movement, together with higli-speed means for rotating said shaft at any desired rate corres onding to the frequency of the fundamenta of any desired note to be produced.

15. In an alarm orsignaling -apparatus of the class described, a diaphragm in combination with a rotary member having an cccentric 'bearing element, a thrust member driven by said eccentric element and having a rigid surface adapted for loose engagement with a diaphragm element to forcibly displace the same in a direction normal to the surface thereof While iermitting free elastic movement beyond t e forced movement, together with high-speed means for rotating said shaft at such rate as to cause said forcible displacements to harmonize with the loose or free elastic movement ofthe diaphragm.

16. In an alarm or signaling apparatus of the class described, a horn or resonator and a dia hragm, in combination with a rotary memfier and diaphragm actuating means actuated thereby and adapted to positively displace said diaphragm in one direction and then to permit elastic movement thereof, and high-speed means for'driv ing said rotary member at such rate that the displacements and the elastic, movements correspond to a frequency of said horn or resonator.

17. In an alarm or signaling apparatus of the class described, 'a dia hragm m combination with a rotary mem e'r and diaphragm actuating means actuated thereby and de signed and arranged to vpositively dis lace said diaphragm in one direction, and ighspeed means for driving said rotary member at such speed that the frequency of displacements harmonize with the 'natural elastic movements of the diaphragm.

1.8. In an alarm or signaling apparatus of the class described, a diaphragm in combination with a reciprocating member for positively displacing the diaphragm in a direction perpendicular to its surface and means for reciprocating said member at a rate synchronizing with the "elasticity of the diaphragm.

19. In an alarm or signaling apparatus of the class described, a diaphragm in combination with a rotary driving member, and means actuated thereby and arranged to positively bend the central portions of said diaphragm in one direction and then to permit free movement thereof, together with high-speed means for. driving said rotary member at a speed sufficient to effect said movements at velocities determined by and harmonizing with a natural frequency of said device.

20. In an alarm or signaling apparatus of the class described, a diaphragm in combination with a rotary member having a member presenting a bearing surface, placed eccentrically, .and tension and thrust connections driven by said eccentric member, adapted toy engage and positively displace the diaphragm in a direction normal to the surface thereof, together with high-speed means for rotating said rotary member so as to displace said tension and thrust connections at a rate corresponding to .the frequency of the fundamental note to be prof duced, substantially as described.

21. In an alarm or signaling apparatus of the class described, a diaphragm in combination with a rotary member having a member presenting a bearing surface, placed eccentrically, tension and thrust connections driven by said eccentric member and loosely engaging a diaphragm member to positively displace the diaphragm in a direction normal to the surface thereof and to permit free elastic movementthereof, together with high-speed means for rotating said rotary member at such rate as to cause displacement-s to occur at a frequency determined by the rate of loose or free elastic movement of the diaphragm.

22. In an alarm or signaling apparatus of the class described, a diaphragm m combination with a rotary member having a member presentinga bearing surface, placed eccentrically, and a tension member driven by said eccentric member, adapted to engage and positively displace a diaphragm member in a direction normal to the surface of the diaphragm, together with high-speed means for rotating said rotary member at a rate corres ending to the frequency of the fundamenta note to be produced, substantially as described.

leo

23. In an alarm o r signaling apparatus of the class described, ar dia jhragm in'y combination with a rotary mem er having a inem-k ber presenting 4a bearing surface, placed eccentrically, .a tension. member driven by, said eccentrlc member and loosely engaging a diaphragm member to positive y displace the `dlaphragm ina direction normal to the surface thereof and to -permit free elastic` movement thereof,together with high-speed means for. rotating said 'rotary member at such rate as to'cause displacements to occur at' a frequency determined by the `rate of loose or free elastic movement of the diaphragm. I

24. In an alarm or signaling apparatus of the4 class described, a horn or resonator and a dia hragm, in combination with a rotary mem er means actuated by said rotary member ada ted to cause bodily movement of said diap ragm on both sides of normal by positively displacing the same in one direction and then permitting elastic movement thereof, and high-speed. means for driving said. rotary member at such rate that the displacements and the elastic movementsharmonize with a natural-frequency of the device.

- 25. ln an alarm or signaling apparatus of the class described, a diaphragm in combination .with crankand link arranged to vibrate said diaphragm alternately on both sides of normal, and means for rotating ,said crank at a rate sufficient to force upon said diaphragm a movement of high velocity, great amplitude, and of frequency sufficient to thereby generate' a loud note, as and for the purpose described.

26; In an alarm or signaling apparatus of the class described, a diaphragm in lcombination with a crank and link arrangedjo vibrate said diaphragm in a direction pert'o t e natural ytime of movementin the free pendicular to its surface at a rate 'sufficient to generate an audible note.

27,.` The method of generating an alarm note of desired pitch and amplitude by means of an elastic diaphragm which comprises periodically applying and removing a positive outward thrust to saidvdiaphragm, dur-- ing its outward vibratory movements, said periodicityof application being at intervals corresponding approximately to thev natural times of outward movement in the free elastic vibrations of said diaphragm.

28; The method of Generating an alarm note of desired pitch an am litude .by means of an elastic diaphragm W ich consists in vpositively and periodically applying and removing 'an outward thrust and an inward vtension-to said. diaphragm, said periodicity of 'a plication corresponding vapproximately elastic vibrations of said da vhragm.

29.y In the generation of a arm notes of desired' pitch kand amplitude, the lmethod of amplifying the vibrations of a diaphragm which comprises' mechanically and positively forcing a portion of each vibration while allowing another portion of such vibration to be free. I

30. In a signaling apparatus for motor conveyances, a case, a hornor resonator secured thereto, a diaphragm and a crank and link driving means therefor within said case,

in combination with a driving connection for the latter extending outside said case and 'including a shaft provided with a nonepositive or slip connection with a source of power.

31. In a signaling apparatus -for motor conveyances, a case, a horn or resonator secured thereto', a diaphragm and a rotary driving member therefor within said case, in combination with a driving connection for the latter extending outside said case and in-.

cluding a shaft provided with a non-positive or s'lip connection with a source of power.

32. vIn a signaling apparatus for motor conveyances, a horn or resonator secured to a suitable case, a diaphragm and mechanical driving means therefor within said case, in combination with a driving connection for the latter extending outside said case and including a shaft provided with a non-positive or slip connection with a sourceof power.

33. In a signaling apparatus for motorv -in combination with a driving connection for the latter extending outside said case andincluding a flexible shaft, a friction wheel, and means for throwing said wheel into and out of driving relations with a motor mechanism of said conveyance.

35. In a signaling apparatus for motor vconveyances, a horn or resonator secured to a suitable case, a diaphragm and mechanical driving means therefor within said case, in combination with a driving connection for the latter extending outside said case and including a flexible shaft, a friction wheel, a bearing therefor and a slidable support for said bearing controlled by the operator for throwing said wheel into and out of driving relation with a motor mechanism of said conveyance.

36. In a signaler alarm of the class described,` an elastic diaphragm, in combina--` tion. with means for bodilyv displacing the ycentral portions of said diaphragm so as to iro put them under elastic stress and for removoutward movement of the diaphragm in the ing said displacing means fast enough to peri same direction by inertia against increasing mit a free elastic reverse movement of saidkelastic stress. l diaphragm. Signed at N eW` York city in the county of 5 37. The method of producing an alarm or signal of the class described which comprises mechanically and positively forcing` a dia- MILLER REESE HUTCHISON.

I phragm in repeated outward vibration be- Witnesses: yond its normal position to a predetermined K. A. MORRIS, 1o position at such a velocity as to cause further L. V. KING.

New York, and State of New York. l5

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