US1881109A - Electric pick-up for phonographs - Google Patents

Description

, O 9 6 o w 2 R E 1 E w W 00 m N O 1 E 1 W W A W a m H WEINER ELECTRIC PICK UP FOR PHONOGRAPHS Filed April 18. 1930 Oct. 4, 1932.

Fatented Oct. 4, 1932 in referring to Figure 2,

v UNITED STA noco WIENER, or issau, mzone ELECTRIC PICK-UP FOR PHONOGRAPHS Application filed April 18, 1930. Serial No. 445,399;

My invention relates to improvements in electric pick ups for phonographs, and it ,slsts in the comb1nat1ons, constructions,

arrangements herein con- and described and claimed.

An object of my invention is to provide an I .electric pick up for phonographs in which novel means is provided whereby sound waves as represented on be converted into impulses, thereby a phonograph record may exactly similar electrical provlding an eflicient converting mechanism.

A further object is to provide a device of the type described embodying means for reproducing the audio frequencies with uni formity and free from distortion.

A further obj ect is to provide a device of the type described in which a novel electromagnet is provided and having its pole pieces characterized by a circular opening, and in which a movable c relation with the oil is disposed in operative electromagnet and within said opening whereby a peculiarly sensitive construction is attained.

'Other objects and advantages will appear in the following specification, and the novel features of the invention will be particularly pointed out in the appended claim.

My invention is panying drawing, plication, Figure in which 1 is an 'GlBVfitlOIlOIE a tone arm emillustrated in the accomforming part of this apbodying my invention,

Fi ure 2 is a sectional view taken along the line 22 of F igure 1, and

. Figure 3 is a sectional view taken substantially In carrying out along the line 33 of Figure 2.

my invention I make use of a tone arm 1 provided with a head 2 which,

comprises a casing opening of its sides. The

iand a it will be noted 3 having a relatively large central opening 5 in one casing is provided with a pin 6 which is concentrically positioned with respect to the have shown a by any sui conductors 8.

In Figures 1 lugs. 9 as beings opening 5. In Figure 2 I field coil 7 as being mounted upon the pin 6. The coil may be energized table source of current through and 2 I have shown rubber ecuredto the face of the casing 3 having the opening 5 therethrough.

The lugs 9 mov ably support a shaft .10 which in turn carries a staif 11 provided with a needle 12.

The shaft 10 is mounted for rotation about its longitudinalaxis which, of

course, permits a similar action of the staff 11. V A movable coil 13 is mounted upon the upper end of the staff 11.

prises a tub lar member The coil com- 14; which is made from sultable insulating material and is provided with spokes 15,

whereby the tubular member may be secured to the staff through the medium of a pin or rivet 16. The tubular member is provided with the required number of turns of suitable wire as indicated at 17.

The movable coil may be operatively connected with an amplifier through the medium of leads 18.

It will be noted in referring to Figure 2 that the movable coil is c tioned with respect to the supported in its proper a members 19 having their on'centrically posiopening 5 and the pin 6. The coil is accurately centered and ligned position by means of a centering device comprising strap outer ends secured to the face of the casing 3 by means of rivets or screws 20. The strap members are connect cured to the stafi through rivet 16. The centering from a suitable material inner ends of the ed together and sethe medium of the device is formed which will permit the movable coil to move in parallelism with the longitudinal axis of the pin 6, but which at all times prevents lateral movement of the coil. 7 I

In operation, the head 2 in connection with the coil 7 provides an electromagnet having its pole pieces magnetic defined by the opening 5. field of great density is built up in the opening 5 by reason of the field coil. The relatively low number of turns of the wire in the movable coil inertia and reactance of 13 provides a low the movable coil.

The undulations on the record cause a relative movement of the staff 11 which in turn is conveyed to the movable coil 13. Due to the fact that the vibrating coil is positioned within a dense magnetic field, the coil will,

of course, in the winding of the coil.

induce a corresponding potential This alternating otential inbein ro erl arn lified b suit-' ble mechanismj llbt shov in, v ill pro ide a perfect reproduction through a loud speaker.

5 A device of the character described comprising a hollow electromagnet having an annular airgapitherein and a stationary mag netic pin centrally disposed in said airgap,

a moving coil member disposed in said air- 510 gap and surrounding said. pin, two rubbers 7 lugsattached to said magnetand having aligned openings therein, a circular rodlhavl 1 ing one end loosely'mounted in eachof said openings, a needle supporting strap-support-V l ed shaft operatively connected to said coil member mounted loosely on said rod at a substantially central portion of-said shaft and said rod, said movable coil member comprising a tubularinsula ting body disposed in said 29 airgapyanda helical coil rigidly attached to the cylindrical insulating member, said rubber lugs resiliently and loosely supporting saidrod i i Signed atBisbee, Ariz in the county of Cochise and State'of Ariz'., this 11th day of AprilAQD. 1930. i s HUGO WIENER

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