US1765586A - Reproducing device - Google Patents

Description

June 24, 1930. J. s. HIGH REPRODUCING DEVICE Filed June 24, 1927.

INVENTOR Jz//y'e/l YH/yh.

A'TTORNEY Patented June 24, 1930 UNITED STATES PATENT OFFICE JURJEN S. HIGH, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA REPRODUCING DEVICE Application led June 24,

My invention relates to reproducing devices, and it has particular relation to phonograph reproducers and to reproducers of the type known as pick-up devices.4 One object of my invention is to provide, in a phonograph reproducing device, means for removing the disagreeable scratching noises that are caused by the oint of the needle scraping the bottom o the record groove.

Another object of my invention is to prol vide, in a phonograph reproducing device, means for absorbing needle vibrations caused by irregularities in the bottom of the record groove, without appreciably lowering the response of the device to intenti ally recorded vibrations of the same filuencies; Numerous attem ts have been' made to eliminate the scratc ing noises from phonographically reproduced music, among which may be mentioned the addition of a soundproof cover that may be lowered over the record andreproducer when the phonograph is operated, and the provision of recordmaterials that aresubstantially grainless in texture. Although both of these schemes accomplish a certain amount of good, a definite amount of noise is stil noticeable, even in connection with phonographs that are among the best on the market.

I have established the fact that the noise just mentioned is caused by minute irregularities in the bottom of the record groove that are made during the process of forming the record, which irregularities tend to actuate the needle-point in a plane substantially perpendicular to the plane in which the needle is moved by the undulations representing the sounds it is' desired to re roduce.

In order that the undesired vi rations initiated by the aforementioned irregularities shall be absorbed and prevented from causing the objectionable background noise, I have, by the present invention, provided a. phonograph reproducer with a needle-holding device so constructed as to dam out all movements of the needle-in the sai perpendicular plane. Specifically, I prefer to mount the needle 50 by a plurality of springs that Hex under the older on the sound box 1927. Serialv No. 201,048.

infiuence of the scratch-irregularities but which are rigid in a direction to transmit the desired vibrations to the diaphragm, `or to the moving armature or coil of a pick-up device. In addition, I associate damping means, such as soft rubber, with the said springs, which absorbs and dissipates the scratch-energy and assists in preventing it from reaching the diaphragm or analogous device.

Among the novel features of my invention, are those particularly set forth in the appended claims. 'Ihe invention in its generic aspect, however, willbest be understood by reference to the following description of certain specific embodiments, taken in connection with the accompanying drawings, in which:

Figure 1 is an end view of a phonograph reproducer embodying a preferred form of my invention;

, Fig. 2 is a view of the device as seen from .below, the `needle-holding elements being shown as sectionalized along a line corresponding to the line II-II of Fig. 1;

Fig. 3 is an end view of""a modified form of my invention, partly in cross-section, and

Fig. 4 is a sectional 'View of they modification shown in'FigJS, taken alon a line corresponding to the line IV-IV o that figure.

Referringv specifically to Figs. 1 and 2,

a preferred vembodiment of'my inventioncomprises a housing 1 provided with .a tubular extension 2 by meansof which 1t ymay be aixed to va phonograph tone arm and which also carries a bearing device 3' 7 and 8 and carrying a lever arm 10 which is connected to a diaphragm 11, is rotatably mounted between the bearing elements.

,J The shaft 6 is provided with a plurality of depending abutment members 12 and 13 lwhich extend -in a direction diametrically opposite to that of the lever arm 10.

A spring 14 of U shape, preferably extremely thin and of high-quality steel, is mounted in a depression in the lower surface of the shaft 6, and is held in position by a small block 15 which is brazed or soldered in place. The legs of the spring 14 extend in a direction parallel to the depending abutment members 12 and 13.

A needle-holding block 16 is suspended between the depending portions of the spring 14 and is clamped thereto by a plurality of screws 17 and washer members 18. The block 16 is provided with an upward extension 20, in which an opening is formed of suiicient size to receive and hold a phonograph needle 21 of the usual type.

Small pieces 22 of resilient material, preferably rubber, having a fairly low sulphur content, are inserted between the depending members 12 and v13= of the shaft and the spring 14, and also between the spring and the upward extension 20 of the needle-carrying block 16. v

Referring specifically to Figs 3 and 4, a modification of the needle-holding assembly comprises an oscillatory shaft 30 to which are affixed, by screws 31 or otherwise, two depending flat springs 32.

A needle-carrying block 33 having a lower rectangular portion 34 and an upper cylindrical portion 35, is mounted between the springs 32 and affixed thereto by means of a plurality of screws 36.

The block 33 is provided with an axial opening 37 having a diameter just sufficiently large to accommodate a phonograph needle of the usual type. A threaded opening 40 is also provided in the block for the accommodation of a needle-holding set screw 41, opening 40 being perpendicular to the opening 37 designed to accommodate the needle, as is customary in devices of this character.

A ring 42 of damping material, such as soft rubber, surrounds the cylindrical extension 35 of the needle-carrying block 33 and is maintained slightlycompressed between the springs 32 and the said extension.

In the operation of the modification of myanvention, shown in Fig. 1, movements of the needle-carrying block in a plane parallel to the iiat sides of the U shaped spring will be transmitted directly to the diaphragm through the lever arm. These are the movements whichrepresent the musical or 'other sounds that have been intentionally recorded on the phonograph record. Other vibratory movements of the needle in planes substantially perpendicular to the aforementloned plane will cause the spring to ex. When the spring iexes to either the one or the other side,the small pieces of rubber. will be more or less compressed, and the energy tending to cause the flexure will be absorbed therein to a very great extent.

The drag of the phonograph needle in the bottom of the recor-,l groove transmits motion to the needle-carrying block which tends to cause it to vibrate in planes in which the springs are flexible. It is this energy which, as previously pointed out, tends to cause the disagreeable background of scratching noise and, since it is absorbed by the rubber or other damping material, it is transmitted to the shaft which carries the lever arm to a very slight extent only. p

The operation of the modification shown in Fig. 3 is substantially the same as the operation of the first described modification. Vibrations of the needle occasioned by sounds intentionally recorded on a record are such as to be transmitted to the shaft through the springs in a plane which may be passed through the lever armand the needle perpendicular to the shaft. To such vibrations, the springs are rigid, inasmuch as the plane referred to is parallel to the flat sides ofthe said springs. Vibrations in planes, other than the plane referred to, tend to cause flexure of the springs and are absorbed and damped out by the rubber ring which encircles the cylindrical portion of the needle-carrying element.

In either modification, I prefer to so construct the springs and the needle-holding block carried thereby that the assembly has a natural period of vibration well above the highest frequency necessary for satisfactory phonograph reproduction. In a commercial embodiment of my invention, I have found that a frequency of 5000 cycles per second is quite desirable.

It is, accordingly, apparent that a phonographv reproducer or a pick-up device constructed according to my invention will have the characteristics of an acoustic filter. Vibrations imparted to the needle by the undulations of the record which represent intentionally recorded sounds are transmitted, unimpaired, to the diaphragm. On the other hand, the vibrations imparted to the needle by the drag of the point thereof in the bottom of the record groove are absorbed by the flexible springs and the rubber damping means. As a consequence, the back-ground of scratching noise is noticeably1 absent from the music or other sounds reproduced by a phonograph equipped with my invention.

The invention is also applicable to magnetic pickups without modification, inasmuch as such pick-up devices are equipped with a needle-carrying assembly `which is substantially the same as that employed in most phonograph reproducers.

The pri-ncipal advantage of my invention lies in the fact that it greatly improves the sound output of either an ordinary phonograph or an electrically actuated phonograph. There is also an additional advantage in that the record itself is subjected meuse to somewhat less wear than when it is uti-y lized to actuate a reproducer ofthe usual type, the semi-resilient mounting of the needle-carrying assembly of my lnvention pick-up devices of t e ordinary type. It

has been customar to connect such a filter, comprising an in uctor and condenser in series, in shunt to the output circuit of an electrical ick-up device and to tune the filter to a requency of approximately 4,000-

cycles per second in order to eliminate the scratch noises. When th1s 1s done, however,

-the filter also eliminates certain desired frequencies from the sound output itself and, consequentl although it lowers the scratch back-ground', it, at the same time, im airs the quality of the music or other soun being reproduced. On the other hand, a device constructedaccording t'o my invention eliminates the scratch frequencies directl at their source without, in any way, impeding the transmission from the record to lthe diaphragm of equivalent frequencies representing musical tones. Y

The device is quite inexpensive to manufacture, and, if dampin means of highquality rubber are utilized, it will have substantially as long a life as a reproduoerof any of the usual types.

Although I have illustrated only two specific forms in which my invention may be embodied, I am fully aware that many modifications thereof are possible. M invention` therefore, is not to be limite except in so far as is necessitated by the prior art and by the spirit of the appended claims. I claim as my invention: c 1. In a reproducing device, a disphragm, a needle-carl` ing assembly rigi con-A nected to sai tions of a phonograph record representin sound intentionally recorded thereon an iexibly connected to said diaphragm in planes approximately perpendicular to the first-mentioned plane. i'

2. In a reproducing device2 a needlecarrying assembl constructed 1n the form of an acoustic ii ter, said filter comprising spring elements having natural eriods higher han those necessary for satis actory phonographic reproduction.

' 3. In a reproducing device a needlecarrying assembly constructed 1n the form of acoustic filter, saidfilte'r comprising damping elements spring elements having "a natural period. above ve thousand cycles per second.

diaphragm 1n the p ane in which the needle is actuatedby the undulan 4. In a reproducing device a needlecarrying assembllyI constructed 1n the form of an acoustic ii ter, said filter comprising springs, and damping elements associate with said springs to limit .the flexing thereof.

45. Ina reproducing device, a diaphragmi a needle-holding device, means interpose therebetween for rigidly transmitting vibrations in one plane only, and further means for absorbing 'vibrations in other lanes.

6. Inv a sound-reproducingl evice, a dia hragm, a stylus-bar aiiixed at one end to sai diaphragm, a st lus-receiving device, and a mechanical ter connecting saidy stylus-receiving device and the other end of! said stylus bar, said filter being resilient il one laneand being rigid in a plane substantially-at right angles thereto.

7. In a vibratory s stem, a shaft, bearings in which said shaft 1s rotatably mounted, a

needle holder affixed to the shaft by means rigid n a plane perpendicular to said shaft and resilientV in a plane parallel to said shaft, and means for damping oscillations of said aixing -means in said last mentioned plane.

In testimony whereof, I have hereunto subscribed my name this.16th day of June,

- JURJEN S. HIGH.

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