US2998496A - Loudspeaker construction - Google Patents

Description

Aug. 29, 1961 J. A. HASSAN LOUDSPEAKER CONSTRUCTION 2 Sheets-Sheet 1 Filed April 29, 1958 FIG.3

Aug. 29, 1961 J. A. HASSAN 2,998,496 LOUDSPEAKER CONSTRUCTION Filed April 29, 1958 2 Sheets-Sheet 2 United States Patent 2,998,496 LOUDSPEAKER CONSTRUCTION Joseph A. Hassan, 818 Main St., South Weymouth, Mass. Filed Apr. 29, 1958, Ser. No. 731,694 3 Claims. (Cl. 179115.'5)

The present invention relates to acoustic devices and,

more particularly, to loudspeakers of the type comprising a frame carrying a voice coil, and a diaphragm integrally including a tapering piston portion, the apex of which is associated with the coil, and a peripheral convoluted portion, the outer edge of which is connected. to the frame. Generally, if the piston portion is to generate frequencies within a desirable sound range, particularly bass frequencies, its diameter should not be too small. Generally, the peripheral convoluted portion, if it is not to restrict unduly the diameter of the piston portion or otherwise affect adversely its operation, must be carefully designed to occupy minimum space and to vibrate freely.

Primary objects of the present invention are to provide, in a loudspeaker of the foregoing type, a plurality of novel components, which are capable of cooperating individually with associated conventional components or collectively with each other in a compact unit of exceptional acoustic range. These components include: novel diaphragm means having straight peripheral edge portions and curved peripheral edge portions; a novel speaker coil construction, and a novel frame construction for carrying the speaker coil construction within the space defined by the diaphragm.

Other objects of the present invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the device possessing the features, properties and relation of elements which will be exemplified in the devices hereinafter described and the scope of which will be indicated in the appended claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following description taken in connection with the accompanying drawing wherein:

FIGURE 1 is a top plan view of a loudspeaker embodying the present invention;

F.G. 2 is a cross-sectional view of the loudspeaker of FIG. 1, taken substantially along the lines 22;

FIG. 3 is a perspective view of a'component of the loudspeaker of FIG. 1;

FIG. 4 is a fragmentary, cross-sectional view of the loudspeaker of FIGS. 1 and 2, taken substantially along the lines 44; I

FIG. 5 is a fragmentary, cross-sectional view of the loudspeaker of FIGS. 1 and 2, takensubstantially along the lines 5--5;

FIG. 6 is a fragmentary, cross-sectional view of an alternative loudspeaker embodying the present invention similar in all respects to the loudspeaker of FIGS. 1 and Lin particular the section analogous to section 4-4 of FIG. 1 being identical thereto, except that the section analogous to section 5-5 is shown in FIG. 6.

, FIG. 7 is a top plan view of an alternative loudspeaker embodying the present invention;

FIG. 8 is a cross-sectional view of the loudspeaker of FIG. 7 taken substantially along the lines 7-7;.

FIG. 9 is a fragmentary cross-sectional view of the loudspeaker of FIGS. 7 and 8, taken substantially along the lines 9-9; and

FIG. 10 is a fragmentary cross-sectional view of the loudspeaker of FIGS. 7 and 8, taken substantially along the lines 10-10.

The loudspeaker of FIGS. -1 and 2, in accordance with the present invention, comprises the rearward frame portion 20, a forward frame portion 22, a generally tapered "ice 2 diaghragm 24, and a coil assembly 26 supported by forward frame section 22 within the dish-shaped space defined by diaphragm 24.

Diaphragm 24, the apex portion of which is connected to coil assembly 26, diverges forwardly with respect to the diaphragm axis at an angle of 20 to 45. Inward portion 28 of diaphragm 24, extending approximately from the apex to the circle partially shown in phantom lines at 30, is substantially conical. The medial portion of diaphragm 24, extending outwardly from circle 30, includes four main panels 32 and four corner panels '34. Main panels 32, the inner portions of which are generally conical and the outer portions of which are generally planar, have straight outer extremities 36. Corner panels 34, both the inner and outer portions of which are generally tapering, have curved extremities 38. The construction is such that the junctions between the main and corner panels are not sharp. Outer extremities 36 of main panels 32 are joined integrally to a series of linearly developed, convoluted portions 40, each of which includes in integral sequence, as best shown in FIG. 4, a. forwardly concave peripheral trough 42, a spacing continuation 44, and a flange 46, which is secured to the frame in a manner to be described below. The outer extremities of corner panels 34 are joined integrally to a series of curvilinearly developed, convoluted portions 48, each of which includes in integral sequence, as best shown in FIG. 5, a forwardly convex peripheral ridge 50, a fiorwardly concave peripheral trough '52, a spacing continuation 54, and a flange 56, which is aiiixed to the frame in a manner to be described below. As shown in FIGS. 4 and 5, the thickness of convoluted portion 40 is less than the thickness of panel 32 and the thickness of convoluted portion 48 is less than the thickness of panel 34 for the purpose of maximizing the flexibility of the convoluted portions and the rigidity of the inward and panel portions which constitute the diaphragm piston. A web 53, connected at its center to magnet 86 and at its periphery to diaphragm 24, serves to rigidify the overall diaphragm support construction.

' It will be noted that, with respect to the axis of diaphragm 24, the slope of trough 42 immediately adjacent to main Panels 32 is greater than the slope of the main panels themselves. It will be noted that, with respect to the axis of diaphragm 24, the slope of ridge 50 immediately adjacent to corner panels 34 is less than the slope of the corner panels themselves. Furthermore, the cross-sectional length of the inner half of trough 42 is less than the combined cross-sectional lengths of the outer half of trough 42 and spacing continuation 44. Likewise, the cross-sectional length of the inner half of trough 52 is less than the combined cross-sectional lengths of the outer half of trough 52 and spacing continuation 54.

' As shown in FIG. 6, in a modification of diaphragm 24, only the outer half of initial ridge 55 is thinned out for the purpose of increasing overall rigidity.

As shown, rearward frame portion 20 is in the form of a dish-shaped basket that includes a rear inward base 60 of relatively small extent and a front outward rim 62 of relatively great extent. Rim 62 is integrally joined to base 60.by rearwardly converging webbing 64. Rim 62 presents a forward face 66 lying in a plane that is perpendicular to its axis. Rim 62 includes a tube 68, substantially hexagonal in cross-section, disposed about the axis of the rim and extending longitudinally thereof a considerable distance for the purpose of accommodating the combined cross-sectional lengths of the outer half of trough 42 and spacing continuation 44 and the outer half of trough 52 plus spacing continuation 54. The edges of rim 62 generally are disposed along the four sides of a square. At the corners of the square, extending outwardly from rim 62 at intervals, are four mounting extensions 70. The medial edges 72 of rim 62 merely constitute the unflanged, free edges of tubular portions 68. Forward frame portion 22 comprises a rim 74 across which extends mounting strip 76. Rim 74 is generally similar in shape to rim 62, comprising four mounting extensions 78 and four medial edges 80. The cooperation between rim 74 and rim 62 is such that flanges 56 of diaphragm 24 are clamped between mounting extensions 70 and 78 and flanges 46 are clamped between edges 72 and 80.

Forward frame portion 22 is secured to rearward frame portion 20 by tubular rivets 82 integral with mounting extensions 70. These rivets initially extend through registered openings 84 in mounting extensions 78 and thereafter are peened outwardly to secure forward frame portion 22 to rearward frame portion 20.

Speaker coil means 26 is mounted within the dishshaped space defined by diaphragm 24 at the rearward end of a permanent magnet 86, the forward externally threaded end of which is turned into an internally threaded ring 88 at the center of forward frame section 22. Magnet 86 includes an inner core pole 90 and an outer annular pole 92, between which is an annular region for receiving the voice coil 100 of coil means 26.

Voice coil 100, in accordance with the present invention, is wound about a tubular element generally designated by 102. As shown, the tubular element, which preferably is composed of aluminum, includes a hollow, cylindrical portion 104, the forward end of which is open and the rearward end of which is provided integrally with a corrugated portion 106. Portion 106 is joined to tubular portion 104 by a convoluted junction 108. As is shown in FIG. 2, portion 106 is secured to the rearward end of core pole 90 and cylindrical portion 104 is disposed between core pole 90 and annular pole 92. This design eliminates the necessity for cementing the usually required dust cap to the apex of the diaphragm.

The loudspeaker of FIGS. 7, 8, 9 and comprises a rearward frame portion 120, a forward frame portion 122, a generally tapered diaphragm 124 and a coil construction 126 and a magnet 127 supported by forward frame section 122 within the dish-shaped space defined by diaphragm 124.

Diaphragm 124, the apex portion of which is connected to-voice coil assembly 1126, diverges forwardly with respect to the diaphragm axis at an angle of 20 to 45. The inward portion of diaphragm 124 extending approximately from the apex to the line shown in phantom lines at 130 is generally curved. The medial portion of diaphragm 124 extending outwardly from circle 130 includes two relatively flat panels 132, 132 and two relatively curved panels 134, 134. Flat panels 132, the inner portions of which are generaly curved, and the outer portions of which are generally planar, have straight outer extremities 136. Generally conical panels 164, both the inner and outer portions of which are generally curved, have curved outer extremities 138. The folds at the junctions of the flat and curved panels are not sharp. Outer extremities 136 of flat panels 132 are joined integrally to a series of linearly developed convoluted portions 140, each of which includes in integral sequence, as best shown in FIG. 9, a forwardly concave peripheral trough 142, a spacing continuation 144 and a flange 146, which is secured to the frame in the manner described above in reference to FIGS. 4 and 5. The outer extremities of curved panels 134 are joined integrally to a series of curvilinearly developed convoluted portions 148, each of which includes in integral sequence, as best shown in FIG. 10, a forwardly convex peripheral ridge 150, a forwardly concave peripheral trough 152, a spacing continuation i154, and a flange 156, which is aflixed to the frame in the manner described above in reference to FIGS. 4 and 5. As shown in FIGS. 9 and 10, the thickness of convoluted portion 140 is less than the thickness of panel 132, and the thickness of convoluted portion 148 is less than the thickness of panel 134 for the pur pose of maximizing the flexibility of the convoluted portions and the rigidity of the inward and panel portions which constitute the diaphragm piston. A web 153, connected at its center to magn t 127 and at its periphery to diaphragm 24, serves to rigidify the overall diaphragm support construction.

It will be noted that with respect to the axis of diaphragm 124 the slope of trough 142, immediately adjacent to the flat panels 132, is greater than the slope of the flat panels themselves. It will be noted that with respect to the axis of diaphragm 124 the slope of ridge 150, immediately adjacent to curved panels 134, is less than the slope of the curved panels themselves. Furthermore, the crosssectional length of the inner half of trough 142 is less than the combined cross-sectional lengths of the outer half of trough 142 and spacing continuation 144. Likewise the cross sectional length of the inner half of trough 152 is less than the combined cross-sectional lengths of the outer half of trough 152 and spacing continuation 154.

In operation, the illustrated loudspeakers are characterized by relatively large piston area within a relatively small frame, the novel convolutions making possible wide acoustic range of exceptional fidelity. In fabrication, the novel voice coil mounting means is assembled with great facility and accuracy.

Since certain changes may be made in the above device without departing from the scope of the invention herein involved, it is intended that all matter contained in the above description and shown in the accompanying drawing shall be interpreted in an illustrative and not in a limiting sense.

What is claimed is:

1. A loudspeaker comprising a frame, a tapering diaphragm having outer extremities secured to said frame, a speaker coil connected to the apex of said diaphragm, a magnetic core, a support mounting said core within the space defined by said diaphragm, and leads extending from said speaker coil, said diaphragm having an inward portion that is generally conical, a medial portion, a plurality of edgewise linearly developed convoluted portions along the outer extremities of said medial portion, a plurality of curvilinearly developed convoluted portions along the outer extremities of said medial portion, said speaker coil being wound about a tubular element one end of which is open and the other end of which is provided integrally with a web, said web being attached to an end of said core, said frame comprising a forward portion and a rearward portion, said forward portion and said rearward portion providing blade-like edges clamping said edgewise linearly developed convoluted portions and said edgewise curvilinearly developed convoluted portions therebetween.

2. A loudspeaker comprising a frame, a tapering diaphragm having outer extremities securedv to said frame, a speaker coil connected to the apex of said diaphragm, a magnetic core, a support mounting said core within the space defined by said diaphragm, and leads extending from said speaker coil, said frame comprising a forward portion and a rearward portion, said forward portion and said rearward portion providing blade-like edges clamping said outer extremities therebetween, said diaphragm having two edgewise linearly developed convoluted portions and two edgewise curvilinearly developed convoluted portions, said linearly developed convoluted portions and said curvilinearly developed convoluted portions being interspersed.

3. A loudspeaker comprising a frame, a tapering diaphragmhaving outer extremities secured to said frame, a speaker coil connected to the apex of said diaphragm, a magnetic core, a support mounting said core within the space defined by said diaphragm and leads extending from said speaker coil, said frame comprising a forward portion and a rearward portion, said forward portion and said rearward portion providing blade-like edges clamping said outer extremities therebetween, said diaphragm having four edgewise linearly developed convoluted portions and four edgewise eurvilinearly developed convoluted portions, said linearly developed convoluted portions and said curvilinearly developed convoluted portions being interspersed.

References Cited in the file of this patent UNITED STATES PATENTS 1,984,019 Hawley Dec. 11, 1934 1,995,080 Shotwell Mar. 19, 1935 2,534,040 Lindley Dec. 12, 1950 2,537,723 Ward Jan. 9, 1951 France Apr. 12, 1951

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