US1762184A - Acoustic device - Google Patents

Description

June 10, 1930. s. w.v M KELLIP ACOUSTIC DEVICE Filed April 1, 1926 INVENTOR:

ATTORNEYS.

sound waves.

Patented June 10, 1930 SPENCER W. MCKELLIP, OF PHILADELPHIA,

PENNSYLVANIA, assre von 'ro wm'r 00K- IANY, 0]! GERMANTOWN, PENNSYLVANIA, A CORPORATION 01' MAINE acousrrc DEVICE Application filed April 1,

My invention relates to a novel construction of. an acoustic device or instrument adapted to be vibrated to reproduce sounds, and to which the vibrations may be imparted'by a loud speaker electromagnetic element, the arrangement of the instrument being such that the original sound waves or vibrations transmitted to the driving element so as to substantially correspond in amplitude, pitch and timbre to the original sound waves without distortion.

By my novel device the vibrations produced by the driving device or electromagnetic element are directly transmitted by a floating tympanum, cone or conical shaped body in such a manner that the latter excites directly in the surrounding free air, sound waves of an intensity and amplitude substantially correspondingto the original M invention in its broad as ects consists in t e provision of a novel oating tympanum or conical body of novel construction and having its free or large end loosely held by but disconnected from a support, whereby the side walls of said cone may accurately respond to the high frequency. vibrations employed in the retproductmn of sounds and im arts said vi rations to a relatively large ody of unconfined air. In carrying out my invention, I employ a novel construction of a floating cone which has its apex reinforced in a novel manner and has its vforward or open end provided with an annular, ripheral, reversely inclined, continuous integral lip or flange, said, tympanum or cone being constructed of light considerable rias hot pressed vibratile material havi gidity within itself, suc

paper, fiber, compressed fibrous material,

parchment, thin animal skin or any other similar membrane capable of producing the desired results. I further construct my novel floating cone, so that the latter as a whole will be extremely light and have as little inertia as possible without a weakenn car g out my invention I mount the repro ucer with an adjustable connection between it and the driving element and 1926. Serial No. 98,987.

seat its periphery against a yielding cushion in such a manner that it is entirely free and unconfined.

With the above ends in view, my floating cone member is provided with an apex reinforced in a novel manner, while theop osite or free end of the cone is provided with a reversely inclined, annular, peripheral flange faced'at its front surface with a felt annulus, the latter being adapted to contact with and be centered in the bevelled wall of a stationary feltannulus sup orted in any convenient manner, as in the f inet, the latter if desired being provided with a grille having a facing of Sllk or other material behind said rille.

My invention furt er consists of other novel features of construction, all as will be hereinafter fully set forth and pointed outin the claims appended hereto.

For the purpose of illustrating my invention I have s own in the accompanying drawings the preferred form thereof, since the same has been found in practice to give Satisfactory and reliableresults, although it is to be understood that the various instrumentalities of which my invention consists can be variously arranged and or anized and that my invention is not limite to the precise arrangement and organization of the mstrumentalities as herein shown and described. In the accompanying drawings Figure 1, represents a erspective viewof an acoustic device, embo ying my invention,

inclosed in a suitable cabinet.

Figure 2 represents a vertical section on line 22 Figure 1.

Figure 3, represents on an enlarged scale a sectional viewof the outer peripheral portion of the floating cone, showing the reversely inclined annular peripheral flange,

the felt attached thereto and the coacting stationary felt annulus. 4

Figure 4, represents on an enlarged scale a sectional view of the apex of the cone,.its reinforcing devices .and the means for ad justing it relatively to the driving element. Figure 5, re resents on, a reduced scale .a front view of t e apex of a cone.

ront of a cab- I Referrin to the drawings in which like reference characters indicate like arts, 1 designates my novel construction 0 a conical sound reproducer or acoustic device, the same comprisin the conical body 2 of paper, parchment or ot er material, having the apex 3, and the opposite open floating end, having its outer peripheral reversely inclined flange 4:, whose outer surface is faced with or has secured thereto the annulus or annular felt ring 5. 6 designates a stationar felt ring or annulus having the inner bevel ed wall 7 of the same inclination as the floating felt annulus 5, said annuli 5 and 6 bein disconnected but in contact as seen in igures 2 and 3. The front wall of the annulus 6 is secured to the front plate 7 x and the o ening 8 through said plate 7 is substantia l the same diameter as the opening 9, throug the stationary felt annulus 6, which latter is relatively thick and forms a cushioned body against which the floating annulus 5 contacts. Through the apex 3 of the cone passes the threaded stem 10 of the head 11, which has the axial passage 12 therethrough for the reed 13, which is held in the desired position by the set screw 14. 15 designates a cone shaped washer positioned at tne inner apex of the cone 2, which is held in position by the nut 16 engaging the threaded stem 10. The outer ortion of the cone at its apex is reinforced by the thin sheet metal star 17 having the radiating arms 18. This construction gives the necessary reinforcement to the outer apex of the cone, with a minimum amount of metal. The front plate 7" may be secured in the front of a suitable cabinet 19, having anopen front in which is the removable grille 20, seated in the upper and lower grooves 21 and 22, said grille having behind it the sheet of silk or other fabric 23, seen in Figure 2, but omitted from Figure 1 for clearness of illustration. The rear of the cabinet as at 24 is open so that there is no confined body of air on either side of the cone to retard or dampen the vibrations thereof.

A very satisfactor regeneration of sounds from the sound vibrated element will be had and the volume thereof may be governed by increasing or decreasing the diameter of the floating annular peripheral flange and the diameter of the apertures 8 and 9.

The altitude of the conical portion 1 may likewise be varied with the diameter to produce the desired pitch of fundamental notes.

In practice I prefer to cement the parts 17 and 15 to the apex of the cone b preferably a suitable acetone cement, an I also prefer to braze or solder the joint between the star 17, and the head 12 at about the point 19 so that the apex of the cone will be tightly and rigidly clamped in position between the parts 17 and 15, so that all the above mentioned elements vibrate as a unit.

In the formation of the floating cone, after blanking out the cone body from paper or other material, I score or crease the same on about the line 20 (see Figs. 2 and 3) and then bend the flange 4 into the position shown, whereby an integral eripheral reinforcement is formed which orms a convenient facing on which to mount the felt strip 5, and affords the latter sufiicient width to form a seat against the cooperating felt ring 6. One object in providing an appreciable area of contact between the two felt rings resides in the fact that the fibers of the two felt pieces interlock, and without ap reciable pressure betwen them it is possi le to support the entire weight of the cone and thus relieve the reed 13 from any lateral displacement.

By the collocation of the stationary, relatively thick felt annulus 6, having its bevelled edge 7 facing and contacting with the inclined floating front annulus 5, said stationary annulus serves at all times as centering means for the free floating end of the cone 1, and so retains it at all times that it is flexible and may move in any direction in accordance with vibrations imparted to it by the reed 13. This arrangement of the parts renders the cone extremely responsive and sensitive at all times to the minutest vibrations and said reed, so that the reproduced sounds are regenerated in and by said cone with remarkable fidelity to the ori inal sound waves. While I have describe the annuli 5 and 6 as being preferably of felt, it will be understood that other similar or equivalent materials may be employed, al though I have attained t e best resu ts from felt annuli. Especial attention is called to the fact that the free end of my novel cone is entirely unsupported in the sense that it is not rigidly attached or secured in any manner to outer rings or other extraneous supporting devices to a support, the vibratile material of which the cone is constructed is free to respond throughout to the movements imparted by the reed or driving element, an at the same time the free edge of the cone is damped against movementi imparted to it by low frequency vibrations beyond the point where discordant notes will be created.

Having thus described my invention,what I claim as new and desire to secure by Letters Patent, is V 1. An acoustic device comprising a support having an opening and a ring of yieldmg material surrounding it and forming a cushion, of a cone of vibratile material having an edging of similar material resting against the cushion and means for vibrating the cone. I

2. An acoustic device comprising a support having an opening and a felt ring surrounding it, of a vibratile cone having a. felt binding strip on its free edge contacting with said ring, and means for vibrating the cone.

3. An acoustic device comprising an apertured support, a felt ring surroundin the aperture and beveled outwardly there rom, of a cone of vibratile material having a flange on its free edge similarly beveled and provided with a strip of felt fitting within the inclined surface of said ring, and means for vibrating said cone.

4. An acoustic device comprising aroma of vibratile material having its open end provided with an annular reversely inclined 'flange, a support, cushioning means positioned between the flange and the support, and means to vibrate the cone.

SPENCER W. McKELLIP.

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