US1760306A - Reproducer arm - Google Patents

Description

May 27, 1930. A. N. GOLDSMITH REPRODUC ER ARM Filed July 29 1925 INVENTOR ALFRED. N. GOLDSMITH TORNEY Patented May 27, 1930 UNITED STATES PATENT OFFICE ALFRED N. GOLDSMITH, OF MOUNT VERNON, NEW YORK, ASSIGNOR TO RADIO COR- PORATION OF AMERICA, A CORPORATION OF DELAWARE REPRODUCER ARM Application filed July 29, 1925. Serial No. 46,702.

My invention relates to reproducers commonly used with phonographs in connection with radio receiving circuits. It has for its object the adaptation, improved operation and simplification of apparatus commonly used with these two types of devices.

For further object it is intended to aid in the manipulation, adjustment and modification of tone which is derived from a phonom graph in a simpler and more eflicient manner than heretofore.

It is well known that an ordinary phonograph is incapable of accurate and minute adjustment by the means furnished with the instrument and particularly so for a person not skilled in the art. My device furnishes means which are simple, readily accessible and easily operated. I accomplish this by locating the tone modifier in the shape of Variable inductance, transformer or potentiometer in a portion of the tone arm or base where it can be reached and manipulated easily. This modifier acts upon a current which is generated directly from the reproduoing device itself. The reproducing device has an electromagnetic arrangement which produces currents according to the sound vibrations. It can be seen in this way that any changes in the control of the output circuit through such a modifier may directly effect any apparatus which is attached to it.

Further and more definite objects may be observed in connection with the annexed drawing, specification and claims.

Fig. 1 of the drawing shows my reproducer, tone arm and support combined with the tone modifier.

Fig. 2 shows a detail of the reproducer.

Fig. 3 shows a section taken on line III-III of the reproducer.

1 shows the electromagnetic arrangement for sending electric currents corresponding to the tone according to the motions of needle 9 on the record 15. This needle is held in socket 10 or by any other suitable means.

3 is a pivoted connection to a rotatable tone arm 16 having a counter-weight 2 mounted on the opposite side from the reproducer 1 in order to counteract some of the weight on the record 15. 16 is free to nicnt of this apparatus and the result is indicated on the scale 19.

Current which is generated in the reproducer 1 is carried along the conductor 17 and into the current varying apparatus 6. Here the conductivity, or the coupling, as the case may be, is varied according to the setting on the indicator 19 and the resultant current is sent out on the conductor 7 to suitable amplifiers or loud speakers as desired.

8 in Fig. 2 shows the shape of the permanent magnet which causes a flow of current in the coil 20 as the armature 11 vibrates back and forth between its respective pole pieces 12 and 13 according to undulations or variations in the record 15. The coil 20 is more clearly shown in Fig. 3. '14 is a flexible mounting piece to allow the armature 11 to vibrate in theproper way.

In the ordinary phonograph reproducing horn, the volume and quality of the tone is often times modified by introducing a sound absorbing body into the throat of the horn by means of a simple shutter. The disadvantage of this arrangement is that it produces reverberation and undesirable resonance periods from such stoppage or reflection of the sound waves. The only way of regulating the actual volume of sound produced is by changing the size and stiffness of the reproducing needle as at 9. This method, too, has its disadvantages which will not be discussed in detail here. It is sufficient to say, however, that a needle of one particular size produces the best results.

lVith this invention a proper size needle may be always used and a direct control of the sound output without resonance, undesirable reverberations or other disagreeable results is possible. It has also been found that the mounting pedestal as 5, should have a large flaring base in order to give it sufficiently rigid support upon its mounting board. In most all casesthis base is made hollow in order .to give the requisite rigidity and to conduct away the sound as has been the custom in the ordinary phonograph. It thus provides convenient location of any sound modifying apparatus.

It hasbeen found that this apparatus may be installed in the ordinary type of phonograph without much difiiculty. It requires only the substitution of the electromagnetic reproducer in place of the diaphragm reproducer and the drilling of mounting holes for the modifying apparatus in thixpedestal. The conducting wire 17 can be run through the ordinary tone arm in the space provided for conducting sound.

In Patent No. 1,677 ,806, granted July 1'}, I

1928, assigned to the same assignee there is described a method of controlling and modifying the tone of electrical phonographs and the circuits therefor. In the present application I desire to claim the incorporation of such apparatus in an electrical phonograph and the structural arrangement therefor.

' Thus having described my invention, I do not wish to be limited to the exact modification shown but only in so far as it would'involve invention to substitute equivalent elements or arrangements of those shown and as indicated in the following claims 1. In a phonograph the combination of, an electromagnetic reproducer, a reproducer arm and pedestal,-an electro-magnetic controlling means constructed and arranged to control the output of said. electro-magnetic reproducer, said means being mounted within said pedestal, means carried by said pedestal to vary the controlling means, and means associated with said last mentioned means to indicate the character of adjustment on said controlling means.

2. In a phonograph the combination of,

an electromagnetic reproducer, a reproducer arm and pedestal, controlling means constructed and arranged to control the output of said electro-m'agnetic reproducer, said means being mounted-within said pedestal, means carried by said pedestal to vary the controlling means, and means associated with said last mentioned means to indicate the character of adjustment on said controlling means.

7 ALFRED N. GOLDSMITH.

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