US1415361A - Reproducer - Google Patents

Description

M. JONES. REPRODUCER- APPLICATION FILED JUNE 19, I917- lAl 5,36 1 Patented May 9, 1922} MARTIN JONES, 0F PHILADELPHIA. PENNSYLVANIA, ASSIGNOR O'F' ONE-HALF TO' JOSEPH S. MAOLAUGHLIN, OF PHILADELPHIA, PENNSYLVANIA.

BEPRODUCER.

Specification of Letters Patent.

Patented May 9, 1922.

Application filed June 19, "1917. Serial No. 175,628.

To all whom it may concern:

Be it known that I. MARTIN JoNns, a citizen of the United States. residing in Philadelphia, Pennsylvania, have invented a Reproducer, of which the following is a specification. I

One object of my invention is to' provide a sound box or reproducer for talking machines which shall be capable of so affecting the sound waves as to produce the required volume of sound without being as heavy as is at present the practice. By reason of the resulting lightening of the reproducer structure there is a reduction of the pressure upon the record and a consequent increase in the useful life of the latter.

A further object of the invention is to so construct a sound box that it shall be capable of giving a more perfect and clearer reproduction of a given .record than is now possible by the use of sound boxes of a similar p I The invention also contemplates a novel arrangement and form of intermediate diaphragm whereby the above noted desirable results are obtained and also a construction whereby vibration of the body of the box is prevented or damped, as are also certain objectionable metallic noises commonly produced when records of a certain class are played.-

These objects and other advantageous ends I secure as hereinafter set forth, reference being had to the accompanying drawings, in which,

Fig. 1 is a plan of a sound box or reproducer constructed according to my invention;

Fig. 2 is a vertical section on the line 2-2, Fig; 1; and

Fig. 3 is a plan of the auxiliary diaphragm forming part of my invention. p In the above drawings, 1 represents the body of a sound box which consists of a flat disk or plate having a tubular boss 2 projecting from the center of one of its facesfor attachment to the tone arm or horn of a talking machine. The opposite fiace of the body 1 has an outwardly projecting flange 3 whereby there is formed a shallow cylindrical cavity whose circular bottom has cemented or otherwise closely held to it a thin, annular sheet 4: of dampening material such as hard or soft rubber, asbestos, gutta. percha, or the like.

Parallel with but spaced away from this lining by a rubber gasket or washer .5 within the cavityof the body. is an auxiliary diaphragm 6, preferably consisting of a circular body ofvulcanized fibre or equivalent material, of less diameter than the cavity of the body but having at opposite points projections 7 which rest upon the washer 0r gasket 5. A second gasket or washer 8 rests upon these projecting portions 7 and upon the intermediate portions of the washer 5 and this has the customary mica diaphragm 9 held to it by a metal ring 10 threaded into the cavity of the diaphragm ;there being a third washer or gasket 11 interposed between this ring and the mica disk.

A stylus lever 12 of any desired construction has one end cemented to the center of the mica diaphragm and if necessary the auxiliary diaphragm 6 is centrally perforated to avoid contact with the adjacent projecting portion of its end. Said stylus lever extends radially outward from the center of the face ofthe sound box and has a transverse portion 13 engaged by a pair of trunnion screws 14 which pass loosely through a pair of lugs 15 respectively projecting up from the outer edge of the flange 3. Each trunnion screw however, has threaded upon it a pair of nuts 16 which cooperate with the lug 15 to immovably hold said trunnion inany adjusted position. The outer portion 17 of the stylus lever is provided with an axial passage or recess for the reception of a needle and has a clamping screw 18 whereby said needle may be rigidly held in place.

By repeated tests I have found that a sound box f the above described construction possesses advantageous features totally lacking in similar devices at present in use, it appearing that the intermediate diaphragm 6 has such an effect upon the sound waves so that the most perfect reproduction of a record is obtained. As shown in the drawings, the diameter of the body of this auxiliary diaphragm is such that there is an annular opening between the spaces in front and at the back ofit, which-opening is of course bridged by the supporting projections 7.

' By the use of the rubber or other dampen. ing lining the blare or metallic noise fre quently heard in reproducing certain records are eliminated, this apparently being due to the fact that th Vibration of the body of the sound box is in a large measure prevented or damped. Moreover by the construction employed no metallic part of the sound box is exposed to the direct action of the sound Waves produced.

By providing lugs 15 through Which the trunnions pass loosely, but to which they are rigidly clamped by their respective pairs of jam nuts, I have found that the loosening of the trunnions' and their gradual disengagement from the stylus lever has been effectually prevented.

I claim v The combination in a sound box of a body having a cylindrical cavity closed at one end'; a main diaphragm mounted across said cavity; a stylus lever attached to said diaphragm; an auxiliary diaphragm in the form of a relatively thin light disc of vulgcanized fibre less in diameter than the cavity MARTiN JONES.

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