US1823457A - Wave reproducing device and process concerning the same - Google Patents

Description

Sept. 15, 1931. c. P. MADSEN 2 WAVE REPRODUCING DEVICE AND PROCESS CONERNING THE SAME Filed Aug. 5, 1924 2 Sheets-Sheet l A TTORNE V mmy/A INVEN TOR c. P. MADSEN 1,823,457

Sept. 15, 1931.

WAVE REPRODUCING DEVICE AND PROCESS CONCERNING THE SAME Filed Aug. 5, 1924 2 Sheets-Sheet 2 Patented Sept. 15, 1931 UNITED STATES PATENT @FFICE CHARLES P. MADSEN, OF NEW YORK, N. Y., ASSIGNOR, BY MESNE ASSIGNMENTS, TO WILLIAM W. VARNEY, OF BALTIMORE, MARYLAND WAVE REPRODUCING DEVICE AND PROCESS CONCERNING THE SAME Application filed August 5, 1924. Serial No. 730,152.

The object of my invention is to simplify the construction of mechanical devices for transforming the mechanical vibrations given the needle by phonograph record or other mechanically operating device into air vibrations, thus generating audible sound and to improve the perfection of this transformation.

While the invention is intended primarily for phonographs and more particularly in connection with lateral cut records, it may also be used with hill and dale type of record, and is also useful in connection with generating sound from other sources than that of the phonograph record, as, for instance, it may be used in connection with electro-magnetically operated devices, such as the loud speaking telephone and used in connection with public address systems, or in connection with radio devices.

In the usual re-production of sound a diaphragm or other vibrating body secured at or near its periphery and vibrated at or near its center, is used, which device is the best that was known and gives results not altogether satisfactory, producing in many cases distortion and impure tones. The above difficulties I have in a great measure overcome.

A further object of my invention is the direct production of wave vibrations and their dispersion in space, thus avoiding amplification.

A further object of my invention is an im proved means of mounting the wave producing appliance.

A further object of my invention is an im proved means of detachably connecting the mechanically operated sound producing appliance to facilitate transportation requirements.

A further object of my invention is an improved vibration producer.

VVith the foregoing and other objects in view, my invention consists of the methods employed, combination and arrangement of systems, apparatus and means as hereinafter specifically provided and illustrated in the accompanying drawings wherein is shown the preferred embodiment of my invention, but it is understood that changes, variations and modifications may be resorted to which come within the scope of the claims hereunto appended.

For practical reasons, devices for transforming the grooved configurations of a phonograph record. or other mechanical de vice, into air vibrations or other vibrations are made of metal, and serious defects are caused thereby. When a metal, or other resonant rocker-arm, is mounted as is usual upon a metal or other resonant support for the diaphragm and air chamber or other vibrating means, molecular vibrations are transmitted from the rocker-arm supporting the needle, or other mechanical device, into the frame or support. Since the sound conductivity of this system is greater because of its greater mass than that of the system comprising the rocker arm and mica disc, the air vibrations imparted to the air column from the two diflerent sources will be out of phase or step, thus resulting in discord and distortion.

Giving a concrete example of the above, I have discovered that by completely insulating the rocker-arm from the sound box metal container by a system of rubber gaskets that the above defect is almost completely overcome and other new and most unexpected results are produced. If the washers be placed under a high compression instead of resisting the vibrations of the rocker-arm, as would be expected, it instead transmits the motion more effectively, but it cannot, on the other hand, turn more than a very small are. It can thus be subjected to enormous shock without injury to the vibrating appliance or other parts to which it is connected, and thus becomes fool-proof. But, furthermore, the resistance to motion of the order of that produced by the record groove is so very slight that it diminishes record wear and surface noises materially.

As intimated above, this device makes it practical to transmit the vibrations direct to the air without the intermediary of a diaphragm of the usual type. This is made possible by the fact that although the rubber washer when under compression will permit motion to the degree imparted by the record i with the groove.

with almost no resistance, its resistance to motion beyond this degree is extremely high and it permits of the support thereon or connection therewith of relatively heavy or clumsy members, which cannot be done when a rocker arm is used tensioned or supported by springs or otherwise as is now common in the art.

In the drawings of the herein-described embodiment of one application of my invention, Fig. 1 is a perspective view of a small, portable phonograph, or talking-machine; Fig. 2 is an enlarged view of a section of a portion of the same taken through line 22 of Fig. 1; Fig. 3 is an enlarged sectional view taken through the center of the securing cone:

Fig. 4 is a development of the resilient cone shown mounted in the above figures. Fig. 5 is an enlarged view taken through line 5 of Figs. 1 and 2; Fig. 6 is a view similar to that shown in Fig. 5 before the several parts are Compressed into position. Fig. 7 shows a modification of the means of maintaining in position the support 5 when vibrated in a rectilinear movement for hill and dale repro duction; Fig. 8 shows a view in elevation of the tone arm carrying support 5, and Fig. 9 shows a modified means of securing the resilient vibrating means together and Fig. 10 shows an enlarged sectional view of the clamping cups and a portion of the cone in relative position before clamping.

Similar numerals refer to similar parts throughout the several views.

1 is a phonograph box containing the driving mechanism and means of revolving disc 2.

3 is a surface to be vibrated, oscillated, or otherwise moved to cause or engender waves and may be made of any suitable flexible material. which will give a maximum of surface for a minimum of weight as, for instance. aluminum, hard rubber, celluloid, bakelized or plain paper. I have found paper, formed as shown in 4 and provided with a gummed edge 4 or secured as shown in Fig. 9 when made of stiff material, to be most desirable, convenient and economical. In this specification when I use the term surface. I mean that which is vibrated in contact with a medium to form desired waves, and include in such term such necessary thickness or body as to maintain the same in shape.

The support, or rocker-arm, 5 carries the member upon which is surface 3, and said support 5 may be made of any suitable material. I use an alloy of aluminum and magnesium known commercially as duraluminum. It is preferably fulcrumed and gives an oscillating movement to surface 3. This in the case of lateral cut records is accomplished by placing the bell crank at right angles to the groove of the record as shown in Figs. 1, 2, 5 and 6, while in the case of hill and dale records, it can be placed parallel This fulcrum is, however,

not absolutely essential, and pleasing results, although not so eflicient, can be obtained by translating the motion into direct rectilinear motion by means of the modification shown in Figure 7.

6 is the re-producer carrier, fulcrumed at 7 to post 19 which is revolvably mounted in the cover of phonograph box 1, as is sometimes done in small portable phonographs.

8 is the fulcrum pin which carries rockerarm 5 by means of rubber bushing 9. rubber washers 10 and 11, metal washer 12, and nut 13. 8 as shown is a stud screwed into arm 6. Upon setting up nut 13, bushing 9 and rubher washers 10 and 11 are highly compressed and cause the various parts to appear substantially rigid, which is not the fact, as heretofore explained.

To obtain the best results, the bushing 9 is made considerably longer than the thickness of the rocker-arm 5, as illustrated in Fig. 6, and, furthermore, fits both the hole in the rocker-arm and the fulcrum 8 very tightly. hen the washers and bushings are compressed by the nut 13 the tension of the bushing and washers will be sufficient to properly support the bell-crank 5. I find it also preferable to use for this bushing a rubber having considerable filler, as, for instance, a

grade of stock used for the outer tires, or

shoes, of automobiles, while for the side washers 10 and 11, I prefer to use a substantially pure vulcanized gum like that from which ordinary rubber bands are made. Other materials will answer for the purpose, and I do not wish to limit my invention to the specific use of rubber; for instance, guttapercha, balata, vulcanized chicle, or any of the vulcanized vegetable oils, as, for instance, corn oil, will answer, although not quite so permanent under high compression as pure vulcanized caoutchouc.

14 is the tracing member, needle, or pin, ordinarily used in phonograph reproduction.

I have found that a ery efficient and pleasing result is obtained by mounting directly upon support 5 a cone-shaped object of paper or other light material. To do this I preferably fasten on top of the rocker-arm 5 a very light, small metallic cone 16 having a vertical threaded stem 15 on the inside. I provide another removable small metallic cone 17, with a threaded nut 18, to fit stem 15 and the relatively large, thin resilient material cone is clamped between the two. Cone-shaped objects may be supplied to the user flat with a triangular section cut out and a hole in the center, as per sketch shown in Fig. 4, when plain paper is used as the material of the cone, or as shown in Fig. 9 I

when stiffer material is used. One side of the flattened cone from which the triangular section is cut is provided with a material 4 which will become adhesive by moistening. These cones may be of various sizes, but preferably are in the flat the same size as the record, which is from ten to twelve inches in diameter. A quantity of them can, therefore, be carried in the record container. The balance of the re-producing system is very small and light and can be carried in the confines of a very small portable machine.

To set up the device for operation it is only necessary to moisten the gummed edge of the flattened cone and set it up and insert it between the cups 16 and 17, securing it in position with screw nut 18 when the device is ready for use. In transporting the device this paper cone is removed and can be flattened again by moistening the joints, but since they are so cheap it is preferable to dis card it and use another one for the neXt set up.

I may also instead of the paper cone provided with a gummed edge, as described above, use a cone of other resilient material with a permanent fastening means which can be readily demounted and set up again. I have found, for instance, that very thin hard vulcanized rubber can be used in this way. In this case I provide one edge with an extra flap between which and the body of the cone the other edge is inserted. If, now, the cone is of slightly greater angle than that of the holding cups, the edges will, in compressing the cups, be forced together and in removing the cups will readily come apart again as shown in Fig. 10.

Having thus described my invention, what I claim and desire to secure by Letters Patent is 1. A phonograph sound reproducing device comprising a rocker arm supported by an organic, resilient material, a small metallic cup rigidly mounted thereon, a removable cup fitted within said first named cup, means for clamping said two cups together, and a relatively large cone diaphragm clamped between said two cups.

2. A phonograph reproducer comprising a supporting means provided with an elastic element within which is positioned a member provided with a needle-holding device, and a diaphragm mounted on the said member, said elastic element being in a compressed condition, and means for compressing said elastic element.

3. A reproducer for a phonograph provided with a carrier mounted to swing over a record to be played, a bell-crank carried by said carrier fulcrumed thereto said bellcrank having secured at one end thereof a stylus and at the other end thereof a vibrating member rigidly secured thereto and wholly supported thereby, said vibrator being substantially of a conoidal shape a side of which is substantially parallel to the disc to be played.

4. In an organized phonograph a reproducer member in part consisting of a vibrating conically shaped member, a reproducer carrying arm pivoted to swing over a record to be played and carrying said conically shaped vibrating member and means for mounting said conically shaped vibrating member with reference to said carrying arm so that said carrying arm and a side of said vibrating member are substantially parallel, a stylus operating said conically vibrating member rigidly attached thereto by means of a carrying member provided to receive a stylus and the axes of said stylus and the said conical vibrating member being substantially parallel.

5. A phonograph reproducer consisting of a supporting member, a vibrating member, a vibrating adjusting means, a fulcrum between the supporting member and the vibrating member said fulcrum having an elastic element positioned between the said two members and means for changing the density of said elastic element.

6. A phonograph vibratory member adjuster consisting of a stylus carrying member and fixedly secured thereunto, an air vibrating member forming substantially a single unit floated in an elastic element, an elastic element floating said stylus carrying member, and means for varying the density of said elastic element.

CHARLES P. MADSEN.

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