US1641630A - Sound amplifier - Google Patents

Description

sept. 6, 1927. 1,641,630

J. B. HAWLEY SOUND AMPLIFIER Filed sept. 26, 1924 2 sheets-sheet 1 sept* 6,1927o 1,641,630

J. B. HAWLEY SOUND AMPLIFIER lFiled Sept. 26, i924 2 sheets-sheet 2 42A .az 36 36 4'6 A #413 l 4IJ 35 55 'I t 34 .34 .sa 3 41'@ 40 47 41 4,

.Patented Sept. 6, 1927.

UNITED STATES..

v 1,641,630 PATENT oFFics.

.resse B. HAwLEmfoF wILMETTE, ILLINOIS.

ivApplicatlon led September 26, 19584. Serial No. 740,009.

This invention relates to sound amplifying horns, particularly adapted for use with phonographs and radio apparatus, and. to -a new apparatus for making such horns.

The invention embodies certain improvements in the horn disclosed in my pending application Serial No. 620,579, filed Feb.

23, 1923, and in the apparatus therein set on a commercial scale in a simple, cheap and practical mannerand in a manner which readily lends itself to the production of any( vdesired type or designof horn;"`to Aprovide an improved sound amplifying horn composed relatively of soft material such as v laccretions of interlaced fiber, preferably, but

not essentially, of pulp fiber, wherein the superficialfibers forming the horn walls arel 'impregnated with a hardeningagent to render the. horn walls substantially nonresonant and more durable; to provide-an ing` horns suchV that thev density and, o r,

` thickness of the hornv wall can be varied at l A will and 'particularly a process for form"- ing a horn wall ofv variant densities; to pro- 'vide an improved horn made in accordance Y with such a process; to provide a sound amplifying horn composed of accretions of interlaced fiber, the superficial fibers being harder so that the .fiberhorn wall comprises 'an inner zone of 'relatively soft4 fibers and outer zone of relatively harder fibers, which l construction yis most ,eicient in dampening fresonance;'to` further provide ahorn thus superficial fibers withany desired har ening gether; Figure 4 is a perspective view of agent such as li. uid glue, resin, asphalt, dry-y constructedfand wherein the harder surface fibers are suitably finished to provide smooth sound reflecting surfaces for augmenting the amplification and 'for rendering the fiber walls more durable; to rovide a novel horn as hereinbefore set fort',v where'-:the hornas thus formed .of accretions of interlaced fibers is surface hardened by impregnatin the ing oils or the ike, Vwhere ly the areeom.- paci-,ed to not only 'render the vernmore urable but also to provide an eXterOPQOatf-f ing of fiber relatively harder than the central fiber portion of the horn wall; and in addition to vrender the horn wall surfaces relatively smoothand hard so as Ito reflect t-he sound waves emitted from the horn' to provide means for removing the blank fi'om la former wherein such means is provided with holding members or devices Such as hooks engaging with the former for holding the same upon the support when the pneu- -matic pressure is applied to release the blank from the former; to provide an improved surface for the preformed blank byl impregnating the surface with suitable substances' to provide a hard, finished and compacted surface; to provide for a hard and brilliant surface as above indicated and, further finishing if desired, by stippl-ing the surface material, and then coating with` varnish, paint o r other` substance upon the Aouter members with relatively finer mesh or improved process for making sound amplifythe interiorof the formers under the suction action, the members of the finer mesh holding thel fibers to be interlaced thereon to form the blanks; to provide the tone arm portion preferably with an addedI outer member of still finer mesh and being preferably a covering of linen orsimilar fabric; and, to provide for such'other'and further objects, capabilities and advantages .as will theI invention.

In the drawings, illustrating the invention, Figure 1` is a view partly invertical elevation and the apparatus or forming the blanks upon ater appear and are `inherently possessed by ai'tlyin vertical `section of a pluralityof formers; Figure 2 is adetailed and fragmentarv top plan view of a part of the same; Figure 3 1s a longitudinal sec-- tional view taken through the former'` with the portions thereof detachablyl secured 1 tothe apparatus for loosening or releasingl the blanks from the former; Figure 5 is a 'longiure 6 is a view in elevation ofthe two porl no vtudinal sectional view of a blank; andFigf I Itions of theformer ready to' be attached tosuspension in a suitable liquid, such as water,

and in more or less homogeneous condition. Suit-able stirring or agitating means is used to maintain a thorough suspension of the fibrous material in the solution. At the upper ends of the walls of the tank inlet conuits 3 are provided through which the fibrous materialis fed to the container 1. Upon the end walls of the container are also provided channels 4 which act as guides for a support 5 having end tongues 6 capable of'sliding vertically in the tracks- 4. rPhe support 5 extends the length of the container and is provided with a plurality of ports 6 over which may be located a plurality of porous horn-shaped formers 7 Aarranged as clearly shown in Figure 1 ofthe drawings. The ports 6 are connected to a `common conduit 8 to an end of which may be connected a fiexible tubing -or hose 9 in turn connected to an outlet pipe 10 secured to and passing through an end wall of the container 1. is suspended at the lower end of Vbales 11 secured to the ends of the support by nuts 12 as shown in Figure 1 of the drawings. The center portion 13 of the bale is connected by a link 14 to a hoisting means or block and tackle 15 supported by a hook 16 to an eye bo'lt 17 fastened to the ceiling 18 of a room. The block and tackle may be operated in an obvious manner for raising and lowering the support 5 from and into the container 1. When lowered into the container 1. the support 5 and the formers 7 thereon, are immersed in the fluidal mass 2. Upon producing a suction by the suction means so that it will be transmitted to the hose 9 and ports 6 into the space interiorly of the formers, the vacuum thus created therein will cause the fluidal mass to press against the exterior of the formers, permitting the 'liquid or water to pass through vthe perforations of the former and interiorly thereof and be drawn from the interior thereof into the pipe 8, hose 9 and pipe 10`to be drained away. The amount of fiber deposited upon the formers and the thickness of the fiber accretion may be regulated by the time or duration of the suction 'action and the amount of vacuum produced within the formers In order to aid the fibers to suitably interlace on the former, the container 1 is preferabl given a vibratory movement as well as 't e mass therein to- .in interlaced accretions whereby to The support 5 v gether with the formers and supports. Due to the suction the fibers will take up a definite relation with each other' on the former so that the fibers will be de osited horn wall of substantiallyuniform fiber arrangement and vofrelatively soft texture which lends itself admirably to the modulation and amplification of the sound waves. It will be apparent that the thickness of the horn wall may be directly controlled by the degree of suction and its duration.

And it is further manifest that since the` initial stagesV of the suction are stronger, due to the fact that the pores of the former are lessfree from clogging the density of the wall will be greater.l

orma

The type of former illustrated is preferably made of two portions, one of bell shape or forming a be'll portion of the former and the other the -tone arm 2,0 of the former. The bell portion 19 preferably has an inner member 21 provided with relatively large perforations and an outer member 22 of foraminous or reticulated material such as.

wire mesh of relatively finer openings .or meshes than the'perforations in the member 21. The tone arm is similarly provided with an inner member 23 having relatively large erforations and .an outer member 24 of oraminous or reticulated material such as wire mesh of relatively smaller mesh or openings than the inner member. Upon the exterior' of the member 24'is preferably provided a -covering or sheathing 25 of fine mesh, such as a, stripof linen or like textile fabric. portions for the purpose of facilitating the removal of the same from the interior of the blank when the blank surrounds the same. These parts 4are made detachable -by providing the bell portion with an ear 26 These formers are made in two j suit-ably threaded or perforated to receive a rod 27 which extends longitudinally through the tone arm' and through an end wall 28 thereof and threaded to receive thumbinuts 29 and 30. By placing the two portions of the former together and with the rod 27 extending through the ear 26 and the j end member 28 the thumb nuts may then be threaded in place and tightened so as to securely hold the tone arm to the bell portion rigidly.

A pluralityof these formers may be placed upon the support-5, as shown, with the tone arms extending '1aterally,`as shown in Figure 1 of the drawings. The formers shown in thisfigure are in transverse section through the'be l port-ion of the formers. 4

The'gradual accretion of the fibers on the porous former produces the roughl shaped horn Blas shown in Figurel of t e drawings. liquid'and the Suction continued until the fibers are consolidated, and slightly dried.4

The formers are now raised out of the I lities, or they may be rolled with wheels havnected a pipe 43 leading to a pressure tanklng designs on their peripheries, or the horns may be left naturally rough. In some instances the horns may be subjected to a com- .pacting, smoothing pressure by means of pneumatic rubber bags in the form of a twopart horn-shaped mould. In this case the horn is placed within the mould sections and the air pressure turned on to inflate the rubber bag sections of the mold to press the mold .walls against the horn. Preferably. this operation is assisted by suction. The suction being turned lon after the bagl mold is placed in position, which increases the sucking head and permits les bag pressure since the pores of the fiber horn are substantially closed by the vrubber bag. If desired, the horn may be given Aany suitable design by forming thebag walls with such a design.

The horn is now ready for drying. Heretofore, itl has been customary to place the blank, still on the former, in an oven Vor otherl heating apparatus. This necessitated ya large number` of formers. In lieu thereof the fiber horn is removed from the porous forlner and placed on a single drying'form during the drying operation. This is cheaper because 1t requires fewer formers to be used.

Means is provided for quickly stripping the fiber horn from` the porous former. Such means is shown in Fi ure 4 of the drawings. It comprises a tale 32 having supporting legs 33 and brackets 34. In the brackets 34 are slidably mounted Shanks 35 of hooks 36 extending above the-table 32. The lower ends of the shanks are connected by a cross rod 37 passing through a pedal 38 lpivotally l supported in floor brackets 39. Coiled springs 4() may be interposed between the brackets 34 and collars 41. secured to the Shanks 35. By operating the pedal 38 the hooks `36 may be moved upwardly over the table 32 and upon releasing the pedal the springs 40 will operate to lower the hooks. In the center of the` table 32 is provided a port 42 to which is con- 44 or other suitable source of air pressure, the y pipe 43 being provided with a control ,-7 Valve'45 having an operating lever 46 connected by a link 47 pivotally connected to a --foot pedal 48. pivotally supported in fioor brackets 49. `By operating the pedal 48 the valve .may be opened or closed to permit the pressure of air to'pass through pipe 43 and port 42. In the operation of this device a former with a blank is placed upon -the table 32 and the hooks-36 made to engage with the vmarginal portions of the former, such as the edge 50 of the bell portion there- Vmesh of the former.

of. Releasingrthe pedals 38 will permitthe spring 40 to hold the hooks in place and hence the former upon the table. The springs 40 are sufiiciently strong to hold this in place for this operation. Inasmuch as the y fibers are more or less intimately in engagement with the mesh of the outer members of the former, it is lordinarily difficult to remove the blank from the former. In this invention this is easily effected by opening the valve-45 and permitting air pressure to be admitted into the interior of the former and blank. This pressure immediately slightly extends the horns, thus releasing `the internal fibers of the blank from the wire p Inasmuch as the covering 22 is of finer mesh the tone arm portion will be easily removed by reason of there being less intimate engagement between the internal fibers of the horn and this part of the former. After the hornhad thus been loosened or released, the foot pedal 38 may be operated to release the hooks 36 from the former and the thumb nuts 29 and 30 removed from the rod 27 so that the bell portion 19 of the former may be removed from the interior of the ,larger endrof the horn. With this bell portion removed the tone arm portion may then be withdrawn toward and through the larger portion of the horn, thus leaving the horn in self-supporting and selfsustaining condition. The horns may be dried in open-air or in an oven with or without heat and with or without more or less moisture content in the atmosphere or surroundin air of the horns. f

The ber horn is next given a surface smoothing operation, in whichy the edges of the horn mouth are sanded to smooth them and if the horn is to be of smooth finish,

the horn. walls'both inside and outside are also given a sanding operation. In addition the stem oi"y the horn isfitted for the ferru'le.

The horn is now ready for the surface hardening treatment. This consists of a chemical treatment of the Superficial fibers of the horn wall to harden them and giver .them .tensile strength. Preferably this 1s accomplished by .immersing the horn in the desired substance.. In the present instance the .horn is dipped in a vat of glue for a desired length of time suitable to impregnate these fibers, the impregnation extending substantially one-sixteenth to one-thirtysecond of an inch. :This treatment not only hardens' these fibers but also compacts them and laysthe fibers better. In lieu of liquid glue, rosin, asphalt, drying oils or equivalent substances may be used.4v After gluing, the hor-n is dried and is then again sanded to smooth condition, the ferrule is positioned and the horn is then given a surface finishing treatment, as, for instance, by stippling, and paintingior by shellac, varnishing or the like lto give the horn walls a hard smooth lUO finish best suited for refiectin i the sound waves and for preventing the a sorption of the sound. y I

, Rather recent acoustical researches and investigations have shown that the modification, distortion or other alteration of the true sound waves emitted by the dia hragm ire the result of causes other than t e resol, nance of the sound horn itself. It has been found that irrespective of the resonance of the horn or diaphragm there is another tone produced by any particular horn which tone varies with .each material and is due directly to the material itself. In ordero to properly identify this characteristic tone modifying property of the horn wall I have termed itpersistency. Investigational measurements 'of this characteristic have shown that this effect is directly proportional to the density of the material used in the horn and is independent of shape or size of the amplifying horn. It is also dependent upon the thickness of the horn walls; by varylngv the thickness of this. wall or different portions thereof, it is possible to increase or decrease theeffect at will. Furthermore, by

J varying the density of different portions of the horn wall, various effects of modifications of persistency can be secured, such for instance as varying the ratio of the relatively soft center to the harder exterior Wood. These investigations have proven l that persistency or variation of the true sound waves emitted by the diaphragm by the horn itself, is much less in a horn composed of interlaced fiber and especially one wherein the outer fibers are compressed or compacted, than in the case of metallic horns, wooden horns or compressed fibers. These results have been confirmed by actual use of a horn constructed in accordance with this invention which makes it quite obvious that with such a hornthe music or speech is comparatively easier to listen to over a period of time and does not become tiring to the listener'as in the .ordinary commercial horn. 'Hence it must b e .manifest that the foregoing process is most peculiarly adapted to the production of sound am l1- fying horns. And this is directly due, rst to the manner in vwhich the horn is formed,

that is, by accretions of interlaced fibers on'l qualities of the sound and tends to eliminate sustained resonance. The adaptability of the foregoing process is also due to the iml' ysofter fibers. This combined relatively so t and relatively hard Wall construction still more reduces sustained resonance, since an vibrations which tend to be set up in the Wa l are substantially at once damped out by these alternate layers. This aids, much, in maintaining an even range of amplification. In addition, in those horns which are given the smooth, hard polished finish on the exterior surfaces of the walls, the reflection of the sound Waves is 'considerably' augmented.,

This also assists amplification `and also increases the durability vand strength of the horn.

In some instances instead of' com acting the outer fibers of the horn wall y impregnation with liquid glue or the like, a somewhat similar tonal quality can be'secured by forming the walls of an inner layer of pulp fiber and outer layers 'of ground leather. The latter is hard and provide's .aj

hard compact surface wall for the horn. The pulp fiber and ground leather are preferably formed by suction. The leather is first sucked on, then the pulp and then the i leather, to provide an even softer zone enf lou closed by harder zones.

vvVhile'I have herein described and upon the drawings shown one way of carrying out the invention, it is to be understood that the invention is not limited to the particular details, construction and arrangement of parts described and shown, but that the invention comprehends other constructions, details and arrangements .of parts without departing from the spirit thereof;y

Having thus described my invention, I claim:

1. 'A sound amplifying horn having walls composed of accretions of interlaced fibers, the superficial fibers of the horn walls being compacted and hardened by impregnation with a suitable material.

2. A sound amplifying horn having walls composed of accretions of interlaced fibers, the fibers of the horn walls being impregnated'i-vi-th a fiber hardening and compacting material. A f

3. A soundamplifying horn having walls composed of accretions of interlaced fibers, the superficial fibers of the horn walls being impregnated with liquid glue to harden and compact the same.

lll

4. A sound amplifier horn composed of I interlaced fibrous accretions, the superficial fibers being impregnated with a suitable liquid.

5. A sound amplifier havin its walls..

composed of accretions of inter aced bers, the supercial fibers forming the inner and 6. A sound amplifier having its walls' com-' posed of accretions .of interlaced fibers, the supercal fibers forming the inner and outer surfaces being harder than the intermediate bers whereby to substantially dampen resonance and rovide durability.

7. A sound amplifier iiaving its .walls composed of accretions of interlaced fibers, the superficial fibers forming the `inner and outer surfaces being impregnated with gluelike material.

8. A sound amplifying'horn having walls composed of accretions of interlaced bers, the superficial fibers of the walls being impregnated with a compacting and hardening agent and suitably smoothed' to form ei- 25 cient sound reecting surfaces.

9. A sound amplifying horn having walls 10.l An accoustic horn comprisin walls 'composed of accretions of interlace fibers,

the accretions of bers being of different densities atA different points between the inner and outer surfaces of said walls.

11. An accoustic horn comprisin walls composed'of accretions of interlace fibers,

thev accretions in one zone having a different density than the accretions in another zone.-

12. A horn com rising walls composed of in various parts of thehorn having different densities, and a surface of the hornbein compacted to produce a hard, efficient soun reflecting surface. v

In witness whereof, I hereunto subscribe my name to this specication.

JESSE B. HAWLEY.

accretions of inter aced bers, the accretions

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