US1748790A - Loud-speaker - Google Patents

Description

Feb. 25, 1930. M. v. OSBORNE LOUD SPEAKER Fig d April 6, 1927 Patented Feb. 25, 1930 MARK V. OSBORNE, OF MASSILLON, OHIO LOUD-SPEAKER Application filed April 6, 1927.

My inventionrelates to loud speakers for amplifying sounds delivered thereto as by the reproducing unit of a radio or thelike and the objects of my invention are to provide a compact, easily and economically manufactured loud speaker which will amplify sounds very efliciently and through a relatively large range of wave lengths.

These objects are attained by a construction and arrangement hereinafter set forth in detail and which may be stated in general terms as including a sound delivery horn communicatinginto but not contacting with one cup shaped deflecting chamber having an open end and whose inner surface preferably conforms to a surface of revolution, and the cup shaped deflecting chamber communicating into but not contacting with an annular deflecting chamber having an open end and an inner surface preferably conforming to a surface of revolution and the annular deflect- I ing chamber similarly communicating with one or more similar annular deflecting chambers.

A preferred embodiment of the invention is illustrated in the accompanying drawing forming part hereof, in which Figure 1 is a part front elevation and part sectional view of the improved loud speaker as on line 11, Fig. 2; and

Fig. 2, an axial sectional view thereof as on line 22, Fig. 1.

Similar numerals refer to similar parts throughout the drawing.

The improved loud speaker indicated generally at 10 includes preferably in the form of an integral casting or the like, an outer shell 11 including preferably concentric and tapered tubular walls 11 11 and 11, the intermediate wall 11 being spaced from and encircling the inner wall 11, and being itself spaced from and encircled by the outer wall 11, and there being a common end closure 11 between one end of the walls 11, 11 and 11.

The inner surfaces of the shell 11 preferably conform to surfaces of revolution about the longitudinal axis XX, and the inner surface 12 of the wall 11 forms a central tapered horn 13 preferably having a smaller outer end 60 14 for sound receiving connection with a Serial No. 181,446.

source of sound as the sound reproducing unit 15 of a radio or the like, indicated in dotted lines in Fig. 2.

The outer surface 16 of the wall 11 together with the inner surface 17 of the wall 11 and the preferably curved inner surface 18 of the end closure 11 form an annular defleeting chamber 19 about the horn 13, the annular deflecting chamber 19 having an open end 20 adjacent the open larger end 21 of the horn.

Another open ended annular deflecting chamber 22 is formed in the shell 11 about the chamber 19 by the outer surface 23 of the wall 11, the inner surface 24 of the wall 11, and the preferably curved inner surface 25 of the end closure 11.

The open end of the wall 11 preferably extends longitudinally beyond the open ends of the wall 11, and preferably terminates in a curved flare 26.

In addition to the outer shell 11, the loud speaker includes also an inner shell 27 preferably in the form of an integral casting or the like, and including preferably concentric and tapered tubular walls 27 and 27, the inner wall 27 being spaced from and encircled by the outer wall 27', and there being a common end closure 27 for one end of the walls 27 and 27 The inner surfaces of the shell 27 preferably conform to surfaces of revolution about the longitudinal axis XX and the inner surface 28 of the wall 27 together with the preferably curved inner surface 29 of the end closure 27, having a central apex 30 outwardly extending therefrom, form a cup shaped deflecting chamber 31 in the shell 27, and the chamber 31 has an open end 32.

An open ended annular deflecting chamber 33 is also formed in the shell 27 about the cup shaped deflecting chamber 31 by the outer surface 34 of the wall 27*, the inner surface 35 of the wall 27*, and the preferably curved inner deflecting surface 36 of the end closure 27 The open end 37 of the annular chamber 33 is preferably spaced slightly back of the open end 32 of the cup chamber 31; and the outer surface of the end closure 27 d is preferably in the form of a tapered cone 38.

The shell 27 is preferably arranged within the shell 11 so that the shells are coaxial, and the open ends of the shell 27 extend in the opposite direction to, and fit over the open ends of the inner walls 11 and 11 of the shell 11, and means are provided which may be sleeves 39 and 39 for laterally spacing the shells from each other, and screws 40 and 40 may be passed through the wall 11, and the sleeves 39 and 39, and screwed into the wall 27 for securing the shells to each other, and the wall 11 is preferably provided with longitudinally extending slots 41 through which the screws extend for providing longitudinal adjustment of the shells with reference to each other.

The sound delivering horn 13 thus communicates into but does not contact with the cup shaped deflecting chamber 31 which itself communicates with but does not contact with the annular deflecting chamber 19, and the chamber 19 communicates with but not contact with the annular deflecting chamber 33 which finally communicates with but does not contact with the annular deflecting chamber 22.

In other words as best illustrated in Fig. 2, the arrangement of the shells 11 and 27 provides for transmitting sound waves and the like, a plurality of reversely directed annular ring passageways communicating with each other and having curved sound deflecting surfaces at the communicating, openings.

By reason of the fact that the tubular walls are tapered as illustrated, a sound wave entering the loud speaker through its horn 13 will travel substantially the total ;,longitudinal distance which it would travel if the loud speaker were in the form of a straight tapered horn having a total length equal to the total length of all of the straight tapered sections of the two shells, and such a straight horn would in itself provide a certain amplification for the sounds entering therein.

In addition to this horn effect, the improved loud speaker is provided with the deflectin efiect on the sound waves of the severa curved deflecting surfaces 29, 18, 36 and 25, successively, which tend to smooth out, for example, musical sounds which may enter the horn 13 and to eliminate to a certain extent undesirable sounds intermingled therewith.

The shell 11 may be provided with suitable feet 42 for supporting the loud speaker on a table or the like.

The arrangement of the solid common end closure 11 for the outer shell 11, and of the conical solid end closure 27 d of the inner shell 27 prevents vibration therein which otherwise might be set up by the sound waves being deflected by the curved inner surfaces thereof.

Moreover the outer conical form of the end closure 27 of the inner shell 27 has been found to deliver the ring-like sound waves issuing from the loud speaker more smoothly than when the outer surface of the end closure is made flat.

I claim:

A loud speaker including an outer shell having walls forming a horn and a deflecting chamber, an inner shell having walls forming a deflecting chamber for receiving sound waves from the outer shell, and means for radially spacing the shells from each other and for adjusting the longitudinal axial distance between the shells.

In testimony that I claim the above, I have hereunto subscribed m name.

MA K V. OSBORNE.

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