US1844787A - Cone type speaker - Google Patents

Description

Feb. 9, 1932. E. B. NEwlLL 1,844,787

GONE TYPE SPEAKER Filed Dec'. 2S, 1950 2 Sheets-Sheet l Menmmwww INVENTOR u 4 ATTORN EYS Feb. 9, 1932.

E. B. NEwlLL 1,844,787

GONE TYPE SPEAKER Filed Deo. 26, 1930 2 Sheets-Sheet 2 -l 171l I 6l e572- 9*! 2:2 u

3 INVENTOR dvx/md5@ w/// umquluw 44,1 ATTORNEYS Patented Feb. 9, 1932 PATENTv OFFICE UNITED STATES EDWARD B. NEWILL, OF DAYTON, OHIO, ASSIGNOR T O GENERAL MOTORS RADIO COR- PORATION, OF DAYTON, OHIO, A CORPORATION OF OHIO GONE TYPE SPEAKER Application led December 26, 1930. Serial No. 504,707.

This invention relates to acoustical devices and articularly to that class of devices in the ra io ii'eld known as loud s eakers. The ideal cone in a loud speaker shou d move as a whole with a piston like action in order to reproduce the low notes or low sound frequencies. To produce a piston like action there is required a stiff cone which might ideally be one with a deep cross section, in the mechanical sense.v On the other hand the ideal cone, figuratively, should break off into sections which move at varying higher frequencies than is practical for the whole cone, in order to reproduce the higher notes. Obviously, and as works out in production, these two requirements Work against each other where resort is made to a single diaphragm only. Thus a single dia hragm is lncapable of accom lishing the esired result, because a uni orm structure throughout the diaphragm that being essential in order `to accomplish the desired movement of the diaphragm as a Whole, responds to a certain frequency depending on the sensibilty or' perhaps stiffness of the vibratory mem- By reason of the diillculties encountered, an acoustic device is provided that has more than one cone, and in which each may be specifically characterized for response to definite portions of the sound range. It is therefore one object of the invention to provide an acoustical device for use in connection with radio instruments that will respond with equal fidelity to the entire range of sound frequencies lmprcssed upon the instrument for reproduction. e

A further object of the invention is to provide a vibrat'ile means for acoustical apparatus, that will respond to the range of sound vibrations without unduly augmenting any particular field thereof.

A further object of the invention is to provide bailie means for a nested diaphragm acoustical device. l

A further object of the invention is to improve acoustical devices in general.

Further objects and advantages of the present invention will be apparent from the 50 following description, reference being had to the accompanying drawings wherein a preferred embodiment of one form of the present invention is clearly shown.v

In the drawings:

Fig. 1 illustrates a longitudinal sectional view of a radio loud speaker illustrating one form of the instant invention.

Figs. 2 and 3 each illustrate by similar sectional view modifications of the invention from that illustrated in Fig. 1.

By reference to Fig. 1 it will be seen that the acoustical instrument here disclosed, comprises a frame of somewhat conical form that supports at its base a grille plate 21, while an actuating motor 30 is secured at the smaller or opposite end of the frame 20'as at 22. The grille 21 may be secured to the frame 2() in any preferred manner as by means of the screws 23 threaded therethru and into a clamping ring 24. For purposes hereinafter to be pointed out, the grille 2l is apertured as at 25 and 26, thus leaving bridging portions 27. n

The motor may be of any desired form, but it is here preferred to illustrate it as of the electro-dynamic type in which there is a cu member 31 provided for a field frame, the ottom wall 32 thereof being apertured at 33 to receive a reduced portion 34 of a core of pole piece 35, also included in the magnetic circuit of the cup 31. For purposes of reenforcing and adding magnetic material to the device, a backing washer or clamp plate 36 is passed over the shank 34 of the core member against which the shank is Vturned over or riveted as illustrated at 37.

In the annular space defined by the side wall of the cup .31 and the core 35, there is deposited a ield winding 40 kprovided with leads 41 and 42, the winding 40 substantially filling the annular space except for a chamber 43 that is receptive of a compressible packing member 44 in the form of a ring just Iitting within the cup 31, and notched at 45 to make way for passage of the leads 41 and 42. The cup 31 is closed at its open end, and thus tends to complete the magnetic circuit by means of a magnetic ring 46, engaging the compressible member 44 and the edge of the cup 31 where it is secured in any desired manner.

` 70 is'also :attached to the intermediate por-.

The ring 46 is notched at 4:7 to make way for the leads 4l and42, and is centrally apertured concentric with, and suiiiciently larger than, the core 35 so'as to provide an air gap ,Hi8 of annular form between the ring 46 and the core 35. rlhe structure thus described denes the passive elements of the motor, completing the magnetic. circuit about the ield coil, the latter of which isV firmly held against axial movement of the core 35 by the' compressible member i4V interposed between the ring 46 and winding 40.

The active elements of the motor, include a flared cylinder 50 forming a support for a voice coil 5l, and thatis disposed for movement in the air gap 48 hereinbetore referred to; The voice coil is provided with leads 52 thatV are Aappropriately supported, and provide communication lwith binding posts 54 from which connection be made to an appropriate `part of the instruments as by leads'55. The flared portion of the cylinder 50 is concentric with and secured to the apex portion- 56 of a conical diaphragm 57, and

to this in any appropriate manner is secured a driving spider 58 being centrally supported Vby a reduced portion 59 coa-xially of the core 35, as by a screw 80 as is well known in the usual practice. lThe spider 5.8 is periph-v erally flanged at 6l that makes provision for the union vwith the apex portion of diaphragink 57, and tends to 'reduce the member to a piston like structure. Exterior of the vflanged portion vof the cylinder 5() there is secured asecond spider which may b-e in- Y wardly iianged or flared at 66 Jfor-attachment with the cylinder 50, and its peripheral edge may be flanged or otherwise turned up at 67 for attachment to the apex portion 68 of aV diaphragm 69. Y An intermediate diaphragm tion of the `spider as by means of its apexial ilange 71. :The remote or base portion oi K used to provide ardriving reiationbetween the voice coil and the apex portion of the various diaphragme, insteadof using the composite Storm as illustrated. n However, itis Abelieved that the constructional form illustrated isV preferable since it produces the results sought after, in Ythat a fairly rigid piston-like structure is provided in accordance with the above sta-ted objects.

y ln Figs. 2 and 3 there are illustrated modiiications Vof the diaphragm arrangement-v In Fig. 2 the free edge diaphragm of Fig. 1 has been replaced by a diaphragm 57a that has its base portion attached to the grille 21 as at 80, substantially in the saine manner as the attachement 7 2 and 7 3 of the diaphragms 65 land 70. The structure illustrated in Fig. 2,in substance is a stepin al progression from the structure of Fig. l to thatof Fig. 3, since the form there illustrated is substantially the saine as illustrated in Fig. 2, except for the intermediateV diaphragm v,TOLwhich has been omitted. The elements of themotor, includ- Yin'gthe voice coil and spiders are essentially the same in each of the three forms illustrated. rlhe remaining essential difference from those'stated above reside in the piercing or formation of the grille 2l,l ,e In eachV instance the grille.' is apertured as at 25 to provide a seriesl of apertures inV ywhatihight be called a peripheral row and openingl into the space between the concentric jdiapliragms, the apertures in each instance extending over anl appropriate Vportion of the grille between the points or" attachment substantially as illustrated so Vthat the diaphragins may be loaded'only to the extent desired. Depending on whether two or inore'diaphragmsare attached to the grille, the apertures Vconform to one or morecircular rows of openings in accordance therewith and the diaphragm bases are attached at the bridging portions 27. In eachV of the forms illustrated, the cen`V tral area or region of the grille is provided with an enlarged openingor sound aperture 26 that is substantially vconcentric with the one or more rows of apertures 25A, and aside from this the central aperture is'V so designed `as to be of a diameter vcoiriinensurate of the base of the smallest" diaphragm attached thereto. It will be noted as in the instance.

oi Fig. 2 where there has been shown a nest ot' three diaphragms, namely5'2a, 70 and69, l

that the apertures of oneannular row are staggered with respecttoethe Vapertures 25 of a concentric. row. By so positioning thel apertures in the grille the'iree dow of airV movement `from one side of theV diaphragm to the other is substantially interrupted, which in eiiect increases'the path oiair movement thereof, thus actingin thenature 'ot a baille plate; That'is to say,` staggering the apertures of `the grille, i air Vmovement from the space between the dia ihra'm 69y and 7G, over the forward edgeof the diaphragm 70 tothe space between it Vuid the diaphragm 5764,01' vice versa, is hindered sufficiently to produce the desired results, since the air movement must take'soniewhat acircuitous path inorder to manifest in that phenomena, rand undesirable' reverberation and mechanical noise of operation are therebyy dainpenedjout, making for a-cleare'r tone product. p Y l When an acoustical device of the form.

illustrated is operatively coupled with a radio receiver, movements of the voice coil 50 will be transmitted to the spiders 58 and (35 or to the single spider if such be used which due to the union with the several diaphragms of the vibratile assembly, will reproduce with exactness the full range of sound impression to which the instrument is subjected. In the form illustrated, particularly that of Fig. l, the spider 58 with its attached diaphragm 57 is more responsive to sound impressions of high frequencies than are those diaphragms concentric and larger than it, and in turn the largest of the nested diaphragms is slower to respond to motor movement-s and is thereby particularly adapted to reproduce sounds of low frequency, while the intermediate diaphragm is well adapted to the reproduction of sound frequencies of an intermediate range.

It is highly desirable that the diaphragms each be selected of a material, or fashioned, or formed, or otherwise prepared so that the independent range of sound response of each diaphragm of the vibratile assembly will overlap the range of one or more of the others of the assembly, thus providing a blending of the sound products of each diaphragm which tend to eliminate the specific prominence of either frequency, whereby the ult-imate sound products of the acoustic device will be natural and pleasing throughout all points in its range of reproduction. In Fig. 1 the vibrating response characteristics are represented by varying the mass and length of the diaphragms 57 and 70, and the pitch of the diaphragm 69, relative to the other two. In Figs. 2 and 3, the result is contributed to by varying the pitch of the cones, and may include use of different and appropriate materials, as for instance papers of different firmness or texture, represented by the various cross hatching of said cones.

Vhile the form of embodiment of the present invention as herein disclosed, constitutes a preferred form. it is to be'understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. In a radio loud speaker, the combination comprising; a motor, a vibratile mechanism actuatable by said motor, said vibratile mechanism comprising a plurality of conic diaphragms having their bases and apices concentric; means securing the bases and apices with respect to said motor so as to b driven thereby.

2. In a radio loud speaker, the combination comprising; a frame; a grille and a motor supported by said frame; a spider supported by the motor, a plurality of diaphragms responding to widely separated sound frequencies and each independently driven by said spider, one or more of said diaphragms being secured to said grille and spider.

3. In a radio loud speaker the combination comprising; a frame; a grille and a motor supported thereby; a driver operable by said motor, a spider yieldingly supportingl the driver; a plurality of diaphragms of conical form secured at their opposite ends to the grille and to the driver, the diaphragms being arranged conoentrically and responding to the same operative impulses of the said motor in different degrees according to high, low and intermediate sound frequencies.

4. In a radio loud speaker, the combination comprising; a motor and means for supporting the same; a plurality of diaphragms actuatable by the motor, some of which diaphragms are secured to the supporting means; a voice coil; a spider connected to the said coil providing an operable connection between the motor and the diaphragms; said diaphragms arranged concentric with the said voice coil, and means securing them to the said spider at increasingly remote portions thereof.

5. A radio loud speaker comprising in combination a frame supporting a motor, said motor including a movable part; a grille covering the frame and spaced from the moter; a plurality of concentric conical diaphragms of truncated form located between the grille and motor and secured to said grille t0 be actuated by said movable part, said grille being apertured at regions intermediate the attachment of the concentric diaphragms whereby said grille will provide a baffle for the same.

6. In a radio loud speaker the combination comprising; a grill-e plate; a plurality of diaphragms secured at their bases to said grille; and a motor connected to drive all of said diaphragme; said grille providing a baffle plate for said diaphragms.

7. The combination set forth in claim 6, wherein, the diaphragms are truncated cones of different diameter and nested one about the other, a spider; and means securing the smaller ends of said cones to the spider so as to be conicidentally responsive to each operative impulse of the motor.

8. In a radio loud speaker having a motor and a driver actuated thereby, a vibratile assembly, comprising in combination; a plurality of truncated cones; a grille supported in parallelism with, but spaced from said driver; means nesting the cones in concentric form between the `driver and the grille; and means securing said cones at their respective ends to the grille and the driver.

9. In a radio loud speaker having a motor and a driver actuated thereby, a vibratile assembly, comprising in combination; a plurality of truncated cones; a grille supported in parallelism with, but spaced from said driver; means nesting the cones in concentric form between the driver and the grille; and means securing the truncated end of each cone t0 the driver at substantially concentric rings `from a central point.

l0. In a radio loud speaker having,` a motor and a driver actuated thereby, a vibratile assembly, comprising' in combination; a plurality of truncated cones; a grille supported in parallelism with, but spaced from said driver; means mounting said cones in the space between the grille and the driver; and means securing the bases and truncated portions ofthe conesto the grille and driver respectively,. at substantially the same respective planes of attachment. l

In testimony whereof I hereto aiix my signature. f EDWARD B. NEVVlLL.

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