US2594759A - Ball point needle for phonographs - Google Patents

Description

April 29, 1952 H. A. FISCHER BALL POINT NEEDLE FOR PHONOGRAPHS Filed Oct. 28, 1949 ATTORNEYS Patented Apr. 29, 1952 UNITED STATES P'EENT OFFICE BALL POINT NEEDLE FOR PHONOGRAPHS Herbert A. Fischer, Langdon, N. Dak. Application October 28, 1949, Serial No. 124,210

1 Claim.

This invention relates to phonograph needles, and more particularly to a phonograph reproducing needle of the permanent type.

A main object of the invention is to provide a novel and improved phonograph needle which is simple in construction, which will resist Wear, and which provides accurate tracking in the grooves of phonograph records on which the needle is employed.

A further object of the invention is to provide an improved permanent phonograph needle which is inexpensive to manufacture, which prolongs the life of records on which it is employed, and which minimizes needle scratch noises in the sound reproduction of the record.

Further objects and advantages of the invention will become apparent from the following description and claim, and from the accompanying drawings, wherein:

Figure 1 is a side elevational view of an improved phonograph needle constructed in accordance with the present invention;

Figure 2 is a vertical cross-sectional view taken on line 22 of Figure 1.

Referring to the drawings, ll designates the shank portion of the needle, said shank portion being formed with a flattened upper portion I2 adapted to be engaged by the set screw of a phonograph pick-up cartridge with which the needle is to be employed. Shank II is formed with an enlarged skirt portion I3 which is internally threaded, as at I 4, and has secured therein an axial stem member I5 formed at its end with a recessed head I6. Designated at I! is a hollow cap member formed with threads I8 engaging within the threads I4 of skirt member I3. Cap member I 1 is formed with a conical tip portion I9 in the end of which is seated a rotatable contact ball 20 which projects through an aperture formed in the end of tip portion I9. Positioned in the tip portion I9 and bearing on the ball member 29 is a commercial diamond 2i, and bearing on the commercial diamond 2i is a conical member 22. Designated at 23 is a generally-conical seat member formed with an axial stud 24 engaging in an axial recess formed in the member 22, as shown in Figure 2, the member 23 having seated in its axial recess, shown at 25, a spring 26 Whose opposite end is seated in the head member I 6. Spring 26 is of a stiffness only sufi'icient to prevent ball 20 from moving upwardly under the weight of the arm of a phonograph during the playing of a record. However, said spring yields slightly, permitting the ball 20 to freely rotate, whereby record wear is reduced during the playing of a record.

Spring 26 exerts an axial force on members 22 and 23, as well as on diamond 2| to maintain contact of the diamond with the inside wall surface of tip I9, even under the weight of the phonograph arm. The diamond 2I is arranged to provide sufficient clearance for the ball 29.

whereby substantially free rotation of the ball 29 is allowed during the playing of a record.

The undulations of the record grooves are transmitted to the ball 20 and through tip I9 and skirt portion I3 to the shank II, and thence to the pick-up cartridge in the well-known manner.

While a specific embodiment of a phonograph needle has been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore, it is intended that no limitations be placed on the invention except as defined by the scope of the appended claim.

What is claimed is:

A phonograph needle comprising a shank having one end formed for securement to a phonograph pickup cartridge, a skirt projecting from the other end of said shank and secured thereto, a hollow cap member having one end open and having the other end formed with a conical tip portion, interengaging means formed exteriorly of said cap member contiguous to the open end thereof and interiorly of said skirt for adjustably securing said cap member in end to end relation with respect to said skirt, the apex of said conical tip portion being provided with an aperture, a record engaging contact ball positioned within said conical tip and seated within said aperture, a bearing element disposed within said conical tipportion and abutting against the walls of the latter for loosely supporting said ball for rotation within said aperture during the playing of a record, a stem disposed axially within said skirt and hollow cap member and having one end secured within said skirt and having the other end terminating in said cap member adjacent to and spaced from said bearing element, and spring means disposed axially within said hollow cap and having one end operatively connected to said bearing element and having the other end supported within said terminating end of said stem for urging said bearing element into abutment with said conical wall.

HERBERT A. FISCHER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 783,389 Roussel Feb. 21, 1905 860,666 Iszard July 23, 1907 949,991 Thoma et al. Feb. 22, 1910 1,915,426 Kohler June 27, 1933 2,485,224 Wahl Oct. 18, 1949 FOREIGN PATENTS Number Country Date 461,361 France Oct. 27, 1913

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