US736948A - Stylus or needle for sound-reproducers. - Google Patents

Description

'PATEN'EED AUG. 25, 1903.

V. H. EMERSON. STYLUS 0R NEEDLE FOR SOUND REPRODUGERS.

PATENTED AUG. 25, 1903. V. H. EMERSON. STYLUS 0E NEEDLE FOR SOUND REPRODUGERS.

are. 736,948

UNITED STATES Patented August 25, 1903.

PATENT OFFICE.

VICTOR EMERSON, OF NEWARK, NEW JERSEY, ASSIGNOR TO AMERICAN GRAPHOPHONE COMPANY, OF WASHINGTON, DISTRICT OF COLUMBIA, A CORPORATION OF WEST VIRGINIA.

STYLUS OR NEEDLE FOR SOUND-REPRODUCERS.

SPECIFICATION forming part of Letters Patent No. 736,948, dated August 25, 1903. Application filed June 27,1902 Serial No. 118,431. (No model.)

To all whom it may concern:

Be it known that I, VICTOR H. EMERSON, a resident of Newark, New Jersey, have invented a new and usefullmproved Stylus or Nee- 5 dle for Sound-Reproducers, which invention is fully set forth in the following specification.

In reproducing sound from flat-disk records, in which the sound-waves are represented by I lateral undulations in a groove of even depth formed in a flat disk of rubber composition or similar hard substance, a pointed stylusneedle' composed entirely of a hard metal, such as steel, has heretofore been employed 1 5 to track the record and transmit vibrations to the diaphragm. This pointed stylus or needle is removably secured in the end of a stylus-arm, which communicates the vibrations to the diaphragm by a lever-like action.

Although the fine point of the stylus or needle is at first sufficiently sharp to engage in the groove and between the side walls thereof, said point rapidly wears away until a part of the conical or tapered point is reached which is of greater diameter than the width of the groove. The result is that shoulders are formed which rest and bear upon the upper flat face of the record contiguous to the groove. As is well known an objectionable 3o sharp grinding, grating, gritting, or scraping noise accompanies the sound reproduced from records of the type above referred to, due to the hard metal of the stylus or point bearing against and riding over the surface of the 3 5 hard substance composing the record-disk. This noise, which is not so objectionable when the reproduction is commenced with a fresh fin ely-pointed stylus orneedle, becomes louder and more objectionable as the point 0 is rapidly worn away and the shoulders above referred to formed thereon. Effort has been made to minimize this objectionable noise by frequent changes of the stylus or needle; but this is-an unsatisfactory expedient, being not only tedious, but ineffectual, the sharp point of the stylus being very materially worn away before the reproduction of a single record has been completed. It is impracticable to reduce the stylus or needle to a uniform diameter approximating the width of he groove, because it would not then have sufficient rigidity to properly transmit vibrations from the record-groove to the diaphragm.

The object of my present invention is to overcome or at least to minimize the objectionable noise above referred to, at the same time avoiding the necessity of frequent. changes of the stylus or needle.

To that end the invention comprises a stylus or needle having a hard core which is supported by, surrounded by, incased, or embedded in a support, body, or covering of softer material. The core, at least at its end which engages the record-groove, is of a uniform diameter approximating the width of the record-groove and is preferably made of hard steel, though other suitable metal or material may be employed. Fine piano-wire has given good practical results. The sup-= port, body, or covering, which is of sufficient thickness ordimensions to impart to the stylus the required rigidity, is made of a softer metal or material than the core, so that it will be readily worn away by contact with the record disk or tablet without producing objectionable noise. An alloy composed of equal parts of bismuth and lead has been found to give good results.

The invention will be more fully understood by reference to the accompanying draw ings, wherein- Figure 1 is a perspective view showing part of a record-disk, a reproducer, and associated part-s. Fig. 2 is alongitudinal sectional view 85 through a stylus or needle embodying my invention. Fig. 3 is a transverse section on line 3 3 of Fig. 2. Fig. 4 is a sectional tlBW showing my improved stylus in engagement with a record-groove. Figs. 5 to 10, inclusive, are views in section and elevation, illustrating other forms in which the invention may be embodied; and Figs. 11 and 12 are views showing a stylus or needle such as heretofore used in engagement with a rec- 5 ord-groove. Figs. 2, 3, 4., 11, and 12 are drawn on a much-enlarged scale, the ordinary dimensions of the sound-groove shown in several of the figures being about five onethousandths of an inch in width by two rco groove.

one-thousandths of an inch in depth. Figs. 5 to 10 are also enlarged views,.but on a smaller scale.

Referring to Fig. 1, A is a reproducer mounted on the outer end of arm 13, which is supported at its other end (not shown) on a universal joint. 0 is a portion of the horn leading into the reproducer. D is the stylusarm of the reproducer, and E is the stylus or needle removably secured in the outer end of the stylus-arm by a set-screw e. The stylus or needle engages and tracks the grooves in the sound-record F, said grooves having lateral undulations corresponding to sound-waves.

In Fig. 11, F is the point of the ordinary pointed steel stylus now commonly used, showing its condition when the operation of reproduction begins. Fig. 12 is a similar view showing the condition of the point after it has been in operation for a short time. The point has Worn away, forming shoulders ff at opposite sides thereof. bear upon the upper flat face of the recorddisk contiguous to the groove,thereby greatly increasing the objectionable sharp scratching, grating, or gritting noise, as above explained.

As shown in Figs. 2, 3, and 4, my improved stylus comprises a core g, preferably of hardsteel wire (such as piano-wire) of a uniform diameter approximating the width (ordinarily five one-thousandths of an inch) of the record-groove, so that no matter how much the end of the core is worn away it will continue to engage between the side walls of the h is a support of softer material, preferably an alloy of equal parts of bismuth and lead, surrounding the core and imparting to the stylus or needle the required ri gidity. The covering may be applied to the core either by dipping it into the alloy while the latter is in a liquid molten state or by molding. As shown in Figs. 2, 3, and 4, the support or covering is elliptical in cross-section, the greatest diameter thereof being preferably disposed transversely to the groove. These figures also show the lower end of the covering tapered to the lower end of the core, so that the latter will readily'en gage the groove at the beginning of the operation. As will be readily understood, as the end of the core is worn ed the support or covering of softer material will also be readily worn away, as indicated, for example, in Fig. 4:, the character of the covering being such that no appreciable sound will result from the wear thereon. The stylus or needle thus constructed can be repeatedly used. In fact, it can be used as long as a sufficient length thereof projects from the stylus-arm.

In Figs. 5 and 6 the covering iis cylindical and of uniform diameter throughout.

It is not necessary that the core be embedded in the center of or be entirely surrounded by the support. Figs. 7 and 8 show the core m embedded in the support at the pe- These shoulders riphery of the latter, while Figs. 9 and 10 show core 0 soldered to the peripheral surface of the support 10.

As will be apparent, modifications may be made within wide limits without departing from the invention.

The term core as used in the specification and claims is intended to designate the hard part of the needle irrespective of whether it is surrounded by and embedded in the softer support, body, or covering or merely secured to the support in such manner as not to be surrounded thereby.

What I claim is- 1. A stylus or needle for use in sound-reproducing instruments composed of a hard core and a support or body of softer material extending along and secured to the core.

2. A stylus or needle for use in sound-reproducing instruments composed of a hard-wire core and a body or support of softer material extending along and secured to the core.

3. A stylus or needle for use in sound-reproducing instruments composed of a core of hard metal and a body or support of softer metal extending along and secured to the core.

4. A stylus or needle for use in sound-reproducing instruments composed of a hard core and a support or body of softer material extending along and in which the core is embedded.

5. A stylus or needle for use in sound-reproducing instruments composed of a hard-metal core and a support or body of softer metal extending along and in which the core is embedded.

6. A stylus or needle for use in sound-reproducing instruments composed of ahard core and a support or covering of softer material extending along and surrounding the core.

7 A stylus or needle for use in sound-reproducing instruments composed of ahard-metal core and a support or covering of softer metal extending along and surrounding the core.

8. A stylus or needle for use in sound-reprod'ucinginstruments composed of a hard-metal core and a support of softer metal containing lead extending along and secured to the core.

- 9. A stylus or needle for use in sound-reproducing instruments composed of a hard-metal core and a support or body of bism nth-lead alloy extending along and secured to the core.

10. Astylus or needle for use in reproducing sound from a groove containing a record thereof, comprising a hard core of a thickness approximating the width of the groove, and a support of softer material secured to the core.

11. A stylus or needle for use in reproducing sound from a groove containing a record thereof, comprising a hard core of a thickness approximating the width of the groove and a support of softer material in which the core is embedded.

12. A stylus or needle for use in reproducing sound from a groove containing a record thereof, comprising a hard core of a thickness approximating the width of the groove and a support of softer material surrounding the core.

13. A stylus or needle for use in reproducing sound from a groove containing a record thereof, comprising a hard-metal core of a thickness approximating the width of the groove and a support of softer material for thereof comprising a hard-steel core of a thickness approximating the width of the record-groove surrounded by a covering of softer metal.

17. A stylus or needle for use in reproducing sound from a groove containing a record thereof comprising a hard-steel core of a thickness approximating the width of the record-groove surrounded by a covering of bismuth-lead alloy.

18. The combination with a record-surface having a, groove therein containing a record of sound, of a reproducer stylus or needle composed of a hard core adapted to engage in the groove and a support of softer material for the core adapted to bear upon the surface of the record adjacent to the groove.

19. The combination with a record-surface having a groove therein containing a record of sound, of a reproducer stylus or needle composed of a hard core adapted to engage in the groove and a support of softer material for the core adapted to bear upon the surface of the record at opposite sides of the groove.

20. A stylus or needle for use in reproducing sound from a groove containing a record thereof, comprising a hard-metal wire core of a diameter approximately the width of the VICTOR H. EMERSON.

Witnesses:

ELISHA K. CAMP, O..A. L. MASSIE.

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