US1406046A - Sound recording and reproducing machine - Google Patents

Description

T 0 LOVELAND scum) RECORDING AND REPRODUCING MACHINE.

APPLICATION FILED JUNE 10, I919.

Patented Feb. 7, 1922.

L L L L K L L L u l I N ll' UNITED STATES PATENT OFFICE.

THEODORE 0'. LOVELAND, or IOWA CITY,

IOWA.

SOUND RECORDING AND REPRODUCIN G MACHINE.

T 0 all 10 from it may concern Be it known that I, THEODORE 0. Love- LAND, a. citizen of the United States, residing at Iowa City, county of Johnson, and State of Iowa, have invented certain new and useful Improvements in Sound Recording and Reproducing Machines; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make" and use the same. 1

This invention relates to sound recording and reproducing machines of the cabinet phonograph type which employ, in addi tion to the usual sound box and tone arm, an amplifying. or tone chamber that is in coupled communication with the tone arm through the medium of a sound conveying conduit, commonly termed the throat, and the specific improvement embodied herein more particularly resides in a novel departure as to the structural treatment of the throat itself. 7

Such throats formed wholly of metal have been, and to a minor extentmay still be, employed in some machines, but it seems impossible to avoid the resultant metallic tones therefrom, and for the transmission of superior tone values it is generally conceded, in this and other musical industries, that wood is the very best material that may be adopted.

These hollow throats, therefore, are preferably formed with walls of a carefully selected wood, and their interior surfaces, must be of a continuously smooth or unobstructed character as their acoustic properties are of the utmost importance, in the transmission of sound waves as constant values from thesound box to the tone chamber of the machine, to insure a delicately accurate reproduction of the record being translated.

It has been observed, however, that in the course of time, regardless of the quality of theseasoned woodor any attempted varnished protection thereof as may have been heretofore practiced, the sound reverbating life and responsive or attuned pitch of the interior surfaces of these wooden walls seem to materially deteriorate, in the sense that they become deadened, as it were, while the walls themselves become slightly warped, separated or otherwise affected, which distorts the continuously smooth or uniform evenness requisite for their proper function Specification of Letters Patent.

Patented Feb. '7, 1922.

1919. Serial No. 303,036.

largely to an excess or an unequal absorption or distribution of moisture, and also by thermal conditions from variable temperatures.

It is manifest, therefore, that such conditlons cause serious alterations, impairment and depreciation of and the primary object of the present invention is to overcome the foregoing and other defects, while at the same time promoting maximum efficiency, in a simple and lasting manner as herein provided for, by the preservation of proper pitch and tone qualities, the maintenance of the sound waves as constant values in their passage from the tone arm to the tone chamber, and the perfection generally of the acoustic qualities of the intermediate throat, the utility and novelty of which latter will be so clearly apparent, as incidental to the following disclosure, that it would only be undesirable surplusage to enlarge further upon the same initially.

With these prefacing remarks, and for a clearer conception of the improved features claimed, reference will now be had to the accompanying drawing, illustrating a practical embodiment thereof, in which drawing the single figure shown is a perspective assembled view of a sound box, its tone arm and a tone chamber, as associated with my improved throat, the latter being partly broken away at its rear and one side wall, and illustrating in section, o an exaggerated scale, my invention as applied.

The numeral 5 designates generally the throat, providing the communicating conduit between the tone arm 6 and the amplifying or tone chamber 7, the said tone arm supporting and communicating with the usual sound box 8, whether of a graphophone, a gramophone, or other type.

The forward wall of the throat, which may also be conveniently designated by the numeral 5, and the rearward wall 9 thereof curve downwardly and forwardly in divergently spaced or flaring relation, for gradually increasing the volume space from the upper or inlet end to the lower or outlet end. The sidewalls are indicated by the numeral 10 and as a rule are very thin, while the forward and rearward walls may be and generally are of comparative heavier thickness.

11 indicates a horizontal support or board disposed within. the cabinet head just below the tone values emitted,

by said board 11 and secured thereto as by the flange member 12, with suitable fastening means therefor.

Thecupper or inlet end of the throat 5 is not positively connected directly to the vertical branch of the tone arm 6, but seats snugly up against the lower face of said board support 11 in encompassing relation with said aperture, and hence in communieating vertical registration with the vertical branch of the tone arm, as is apparent. The lower or outlet end of the throat is somewhat analogously mounted to register with a 'rear or inlet opening ofthe tone chamber 7, and the throat may conveniently by the upper and the lower guide or centering elements 13 and let,

respectively.

15 designates, on an exaggerated scale for clearness of illustration, a metallic resurfacing lining or coating, for the interior surfaces of the throat, which incorporates ajmetallic layer or leaf, of film-like thinness, in the finish, and which comprisesthe primary essential of the present invention, although I may and generally do apply an analogous coating 16 to the exterior surfaces also, with highly beneficial results especially as to the exclusion of moisture.

It might be contended that it would be a full equivalent tosmoothly lay and secure a sheathing of metal over the surfaces, but it should be distinctly borne in mind that such is not the case, for. in that event the lining would have a limited or dampered vibration with a consequent flat metallic or so-called tin-panny resonant quality, which would be quite as objectionable as if the throat was of all-metal formation, when its freer vibrations would cause either harsh grating metallic twangs'or ringing. tones, largely dependent upon the resonance of the metal, and at all events any such concitions would defeat the perfected acoustic properties sought for, in maintaining the desired purity of tone values.

It is to be emphasized, therefore, that the said lining 15 is in fact a true resurfacing agent, in that it becomes an incorporate part 5 of the interior wooden surfaces themselves,

closing the wall joinders and filling up the pores of said interiorwall surfaces in the manner of a hermetic seal, and forming as it were a stratified film-like 'metallic facing,

5 which serves both inthe capacity of a moisture and air proof reinforcing veneer as well as improving or at least maintaining constant the tone values to be emitted. ()bviously the same may be said of the exterior be held po-' sitioned in any suitable way, illustrated coating 16, excepting that the latter is not contacted by the sound waves.

This broad metallic resurfacing feature might possibly be accomplished in other equivalent ways, but in actual practice I have found and demonstrated that a suitable veneering agent may simply comprise a coating of gold or aluminum leaf or their equivalent, which maybe applied to either the interior wall surfaces alone, or both interiorly and exteriorly, by any of the meth- V ods usually employed in causing the adhesion of metallic leaf.

lVhether or not I have exactly stated the proper reasons therefor,experimental and commercial use have assuredly proven that my discovery is of superior importance, in point of preserving the purity of tone values, as has been evidenced by careful comparisons between the same machines,

under exactly the same conditions and trans lating the same identical records, excepting that in one instance themachine has been specification and understood equivalents,

and having thus made a full disclosure of my invention'as now practiced, what I do claim as new and patentable is 1. In machines of the character disclosed,

the employment of a wooden throat, em-

bodyinga sound wave conducting passage,

which is internally and externally resur faced, with a suitable positively adhering metallic leaf, to provide uniformly smooth solidly Wfiflflil-lJZ-Ullifid metallic surfaces. of him-like thinness. both interiorlv and eX- teriorly thereof. 7

In machines of the character disclosed, the combination witl'i a sound box and tone amplifying chamber spaced therefrom, of intermediatemeans providing a sound wave conveying conduit, leading from said sound box to said tone amplifying chamber, which conduit includes a woodenthroat that is internally resurfaced, with a suitable positively adhering metallic leaf, to provide a uniformly smooth and solidly wood-backed film-like metallic lining surface for the interior thereof.

In testimony whereof, I aflix my signa-.

This was true also whether or not

Images