US1229780A - Sound-box for talking-machines. - Google Patents

Description

W. OPEL. SOUND BOX FOR TALKING'MACHINES.

APPLICATION FILED MAR. 5. 1915.

Patented June 12, 1917.

j 66 01" may.

-WALTER OPEL, or LnIrzIe, GERMANY.

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rec ss To all whom it may concern: Beit known that I,- WALTER OPEL, a minzen of Germany, and a, resident of Leipzig,

Saxony, State of Germany, have invented certain new and useful Improvements in or relating to Sound Boxes for Talking Machines, of which thefollowing is a specification.

In order to increase or to weaken the tone action in talking machines use is made in connection with the sound-box of needles of appropriately greater or smaller thickness. It is, therefore, necessary to interrupt the playing when an alteration in the tone is to be obtained. Moreover, the exchange of the needles is not only costly but frequently results in inconveniences. 'Experiments have been made with a view to changing the tone action by enlarging or increasing the passage, in the sound tube by means of a closing member. The known devices of this kind, however, have the drawback that the individual oscillations of the closing member re- :sult in disturbing noises while at the same time the adjustment is socomplicated and diflicult that it cannot be efiected during playing.

The object of this invention is to avoid the above defects by controlling the clear passage of the sound-box casing with the aid of two superposed disks having perforations whlch are adapted to register with each other. This is accomplished by making one disk rotatable, that is to say, this disk is capable of oscillating about an axis so that its perforation more or less frees that of the other disk as will be more clearly underthe accompany-- stood from a description of ing drawings, in which Figure 1 is a front view of the improved sound-box,

Fig. 2 is a partial elevation and vertical section thereof, on the line a-b of Fig. I,

' Fig. 3 is a front view of a modified con-' struction.

In the example shown, the casing A of the sound-box has connected to it a socket B which is provided with a box-shaped enlargement O, as best shown in Fi 2. This enlargement serves as the soun chamber proper of the sound-box. The sound-box itself is closed by a disk D which serves also as a carrier of the socket B. The disk D is Specification of Letters Patent.

Patented June 12, ILQIL '3...

Application filed March 5, 1915. Serial No. 12,237.-

provided with perforations E through which the sounds produced by the diaphragm F about an axis G is a second disk H provided with perforations I. The perforations in the disk H and those in the disk D are so located with regard to one another as to enable the clear passage to be regulated by the rotation of the disk H.

The disk His journaled about a relatively light axis or bolt G. This disk H is easily rotatable on the adjoining face of the disk ]D. The disk H consists, by preference, of vulcanized fiber, felt or other material which is not liable to individual vibrations causing disturbing noises. In order to prevent oscillations of the disk H from being transmitted to the disk D, provision may be made also' between the two disks of a layer 0 of felt or like material. The contact, however, between the two disks may be insured by a weak spring K which is slipped over the axis G.

In this manner, while safeguarding a reliable bearing of the rotary disk H on the stationary disk D, an easy rotation of the disk H and thereby a ready variation'of the free passage for the sound is at all times assured. By introducing through a slot L in the casing C a bent pin M into the disk H so as to serve as a pointer or indicator, theextent of the adjustment of the disk H with regard to the disk I) may readily be read ofi from a dial N on the sound-box. It is, therefore, possible to vary the strength of the tone in talking machines of this kind by merely adjusting the pointer N on the dial and this may be effected even during the playing.

In the constructional example shown in 3, one of the disks is provided with three perforations E E E of gradually increasing diameter, thereby enabling the strength of the tone to be regulated from the finest pianissimo to the strongest fortissimo.

To this end the second disk is provided withthe disk m mm . In the constructional forms illustrated the axis G has a central arrangement, but it is obvious that it may have an eccentric'al arrangement partic arly in the case in which H is to perform merely an oscillating movement on the disk D.

I claim as my invention: 1. A. sound box for talkingmachines in which the regulation of the tone is elfected by superposed perforated disks, comprising the sound box casing with perforated rear wall, a box shaped enlargement provided on the rear wall of the sound box casingand adapted to house a perforated disk, a central 1 aao eo shaft for said disk "within the box and enlargement, and a spring on said shaft adapt.-

ed to press the perforated disk against the. vperforated rear wall of the sound box.

2. A sound box for talking machines, comprising the sound box casing with perforated rear wall, a box shaped enlargement provided on the rear Wall of the sound box casing, a central shaft within said casing and enlargement,.and means on said central shaft for regulating the tone.

Signed at Leipzig; Germany this 11" day of February 1915-.

. WALTER OPEL.

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