US1830801A - Magnetic pick-up device - Google Patents

Description

Nov. 10, 1931. S. MCCLATCHIE 1,830,801

MAGNETIC PICK-UP DEVICE Filed Dec. 7, 1929 2 Sheets-Sheet 1 ,HVEHTOE' BY 6tanleg me C'IaZc/vie HTTORNEYT Nov. 10, 1931. s. MCCLATCHIE MAGNETIC PICK-UP DEVICE Filed Dec. 7, 1929 2 Sheets-Sheet 2 IHVEIYTO/i SfanIeq me Clafchie HTTORHEY Patented Nov. 10, 1931 UNITED STATES PATENT OFFICE STANLEY MCCLATCHIE, or neanin-wrmvmnsnonr,GERMANY MAGNETIC lICK-UP DEVICE v 1 Application flled December 7, 1929, Serial No. 412,490, and in Germany July 5, 1929.

This invention relates to magnetic pick-up devices, especially for use for reproducing sound from phonograph records. 7

Phonograph pick-ups as hitherto known, have the drawback that it is difficult to assemble, interchange and adjust individual parts. This is particularly objectionable in the case of the esential moving part of the pick-up, the armature with its associated damping means of rubber. As is well known, rubber rapidly loses its original elasticity, so that in the course of from four months to one year, the operation of thepick-up is markedly impaired.

It is the object of this invention to overcome the afore-mentioned drawbacks and to provide -a sound-box which consists essen tially of two parts, 1) a casing with themagnet, spool and pole-pieces, and (2) a readily detachable and adjustable supporting member for the armature with its rubber damping in providing simple clamping means for keep ing the needle in its supporting element,

which clamping means are arranged so as not to oscillate with the needle.

Further objects of the invention will b'ecome apparent fromthe following description taken in reference to the appended draw ings and disclosing, by way of illustration,

some practical forms of embodiment of the invention. 7

Referring to the drawings, Figure 1 shows 'a preferred form of pick-up in accordance I with my invention, in a longitudinal section.

Figure 2 is a cross-section taken at right angles tothe section of Figure 1.

Figure 3 is an enlarged cross-section of a idftail of Figure 2, taken at the section-line -B. Figure 1 illustrates an alternative construction.

fastening of the spool flange to the separating i Figure 5 is a fragmentary section of a de-, vice as shown 1n Figure 4, but with modified means for holding the needle in an operating wall between the main casing and its detachable part, by means of eyelets, which,'at the same time, serve as terminal connections for the coil. j v I Figures 8 and 9-show respectively, sections taken on' the section-lines A-'B and 'C-'D of Figure 4. r 1 Similar reference numbersreferto similar elements throughout, the different views of the drawings. 7. y j c Referring to Figures land 2, a magnet 1, which is preferably a permanent magnet and which may be rotated by means, of a knob 26, is mounted attheupper part of-a .0255 ing 2, and 2a, with a resilient spacing Inem-j ber placed between. The spool 4 has flange 5, whichis clamped, together with the pole-pieces :6 and tl1Qd1SC37, between the two;

halves of the ,casing2'and 2a. The casing bushings 10, 11. The disc,7. serves to pre-' A- further object of my 1nvent1on conslsts surrounded by a rubbercushion13,which is held by air inward tubular extension 1 of the supporting member 15. The upper" part of the armature tube. 12 ,is provided with I indentations 16, which serve as a stop for. the needle, which thus can only be. inserted to a predetermined depth. The needle 17 is held in operating position in the armature .12 by means of a clamp 18, which, through the spring 19, exerts a pressure against the needle at the point which is theaxis of oscillation. At'this point, the clamp does not inter ferewiththe needles movement. The clamp has a'press-button portion 20 and atongue 21, which latter serves to. force the needle into the wedge-shaped-polition 12a of the armature 12.. (See Figure 3.) Infthe embodiment shown in Figures 4 and 7 the clamp consists of a bent elastic wire 21a, carried by the member; 15 and having anoutside extension through a slotof the casing. In this embodiment, the armature holder 15 is extended to form the cup-shaped lower casing portion, whichin Figure 1 is, the separate'part 2a. The spoolflange 8 is here secured to the casing 2 by the eyelets 22, shown on an enlarged scale in Figure 7.

In the embodiment, according to Figures 5 and 6, the pressure member for the needle 17 consists of a tongue 26 of a slider 18a, which is forced against the needle 17 through the action of a rubber cushion 23. Vhen it is desired to exchange needles, it is merely necessary to de'pressthe portion 20 of the slider 18a.

The detachable part 15 with associated armature system, is secured to the main casing by means of the set- screws 24 and 25. A resilient gasket 28 is interposed. The washer 27 of Figure 1 servesto strengthen the holder 15 where the screws force the holder against the gasket. l

The various forms just described have, in common, that the armature system, with an associated supporting structure,is detachably and adjustably secured to the main body of the pick-up. Provision is thus made for readily renewing the armature system as soon as the rubber damping begins to deteriorate.

In practice,the dealer selling the device would carry in stock fresh armature systems for renewal. He has merely to remove the two setscrews 24 and 25 and attach a new system. The positi on of the armature between the pole pieces is readily adjusted by means of a phonograph needle inserted in one of the transverse holes shown in the screw This adj-ustment ma y be carried out 'while the picle up is'actu'ally playing-,which makes the operation simple even for a layman, as he may thus gauge the correct adjustment by ear.

Furthermore, the interchange of needles is greatly'facilitated by the use of a clamp, instead of a set-screw, as has heretofore been customary. This construction has the further advantage of relieving the armature of the undesirable additional weight of the setscrew with its associated threaded holder.

It is evident that my invention may be embodied in other forms and in other associations of elements than thosehere shown, and that the scope of the invention is not to be construed as limited to the particular structures and combinations described and illustrated.

What I claim is':

1. A sound reproducing pick-up device for phonographs and the like, comprising, in combination, a main supporting structure, a

detachable part of said structure, a phonograph needle to be subjected to mechanical oscillations corresponding to the oscillations of sound to be reproduced-ii cushion of'elastic material carried by said detachable part to simultaneously serve for "holding said needle in operating position and acting as a dampening means for said mechanical oscil-' lations.

In a sound reproducing pick-up device, tor phonographs and'the like, comprising, in

combination, a main casing structure, a detachable part of said casing, an element subjected to mechanical vibrations corresponding to the vibrations of sound to be reproduced and a cushion member of elastic material carried by said detachable part to serve as a support of said element and as a dampening means of said mechanical vibrations.

'3. In a sound reproducing pick-up device for phonographs and the like, comprising, in combination, a main casingstructnre, an operating magnet, a detachable part of said casing, .a phonograph needle subjected to mechanical oscillations corresponding to oscillations of sound to be reproduced, a cushion member of elastic material carried by said detachable part, a magnetic armature cooperating with said magnet held by said cushion member and engaging said needle in a clamping position, whereby said cushion, simultaneously serves as a pivotal support of said needle and as a dampening-means of said mechanical oscillations.

4. Ina sound reproducing pick-up device for p'honographs and the like, comprising. in

combination. a main casing, a detachable part of said casing. a magnet structure carried by said casing, a cushion member of elastic material carried by said detachable part. a

phonograph needle to be subjected to mechanical oscillations corresponding to the oscillations of soundto be reproduced, a ma gnetic armature cooperating with said magnet, being held in a clamped position within said cushion member. and engaging said needle, said cushion serving as a support for said armature and as a means for dampening its oscillations. p

In an electro-magnetie sound re- 'n-oducing'pic'k-up device for phonographs and the like, comprising, in combination, a main casing structure, a magnet carried b v said structure, pole pieces of said magnet. a detachable part of said main structure, a phonograph needle to be subjected to mechanical oscillations corresponding to the oscillations of sound to be reproduced, a cushion of elastic material carried by said detachable part and arranged between said pole pieces, said needle being supported by said cushion. serving at the same time as a dampening member for said mechanical oscillations.

6. In an electro-magnetic sound 'reproduc ing pick-up device for phonographs and the like, comprising, in combination, a main casing structure,a magnet carried by said struc V material carried by said detachable part and" arranged between said pole pieces, a sleeve-- like magnetic armature held in a clamped position Within sa d cushion and engaging to be subjected to mechanical oscillations corresponding to the oscillations of sound to be reproduced, a metallic sleeve within said rubber tube to serve as operating armature of said pickup device and holding said needle in operating position, said rubber tube simultaneously serving as a dampening member of said mechanical oscillations 8. In a phonograph sound reproducing pick-up device, as described in claim 7, wherein said detachable part is adjustably con-' nected to said main structure by means of intermediate layers of elasticmaterial.

9. In an electro-magnetic sound reproducing pick-up devicefor phonographs and the like, comprising, in combination, a main casing structure, a magnet within said casing, a detachable part of said structure, pole pieces of said magnet, a rubber tube element carried by a tubular extension of said detachable part and arranged between said pole pieces,

a metallic sleeve within said rubber tube to serve as operating armature of said pick-up device, a phonograph needle to be subjected to mechanical oscillations corresponding to the oscillations of sound to be reproduced, said needle being carried by said sleeve in clamped position, whereby said rubber tube simultaneously serves to support said needle in operating position and to dampen said mechanical oscillations. I

10. In a phonograph pick-up device, as described in claim 9', wherein. said detachable part is adjustably connected to said main casing structure by means of lntermediate elastic layers.

11. In an electro-magnetic sound reproduc- 7 by a tubular extension of said detachable needle in said armature sleeve, said pressure element being arranged to be movably mounted to apply its pressure to said needle and to hold it in its armature.

12. In an electro-ma etic phonograph pickup device, as descri ed in claim 11, in which. said pressure element consists of a slider associated with said main casing provided with a slot for receiving needle armature and a spring member between said slider and said main casing pressing said needle against the inside of its armature.

13. In an electro-magnetic sound reproducing pick-up device for phonographs andthe like, comprising, in combination, a main cas-' ing structure, a magnet within said casing, a detachable cup-shaped part of said structure, pole pieces of said magnet arranged within said detachable part, a rubber tube element carried by an inward tubular extension of said detachable part and arranged between said pole pieces, a metallic sleeve within said rubber tube to serve as operating armature of said pick-up device, a phonograph needle to be subjected to mechanical oscillations corresponding to the oscillations of sound to be reproduced, said needle being carried by said sleeve in operating position, whereby said rubber tube simultaneously serves as a pivotal support for said needle and as a dampen ing member of said mechanical oscillations and a pressure element, together with a spring for holding said needle in said armature sleeve, said pressure element being arranged to be inovablyi mounted against the action of said spring on said detachable part to apply its pressure to said needleand to hold it in its armature. i g

14. In an electro-magnetic phonograph pick-up device, as described in claim 13, in which said pressure element consists of a metal plate with a bent over part and an elastic member co-operating with said bent over part to exercise pressure of said needle to retain it in its position within said armature. In testimony whereof I affix my signature.

STANLEY MCCLATCHIE.

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