US1468224A - Tone arm for phonographs - Google Patents

Description

Sept. 18 l1923.

1,468,224 A B. B. BLOOD.

, TONE ARM-FOR PHoNoGRAPHs Filed Jan. 16 1919 will! Patented Sept.Y 18, Y

BUI-'tn B. BLOOD, orgcHIcAGo, ILLINOIS, 'kssrenonfnr v-ivrns1\na Assrcfniann'rs,k To

ILLINOIS. y

YApplication filed Januaryiis, '-ieia srriai-Vnd; 27i;376

'T 0 all@ hom may'cofricera:

zenof theUnited States,v:and aVV resident jof fllinois,y have invented certain new andause'- ful Improvements in Tone Arms for Phonographs,V of which the following' is aV description, reference being had to the accompanyingjdrawing, which forms apart V,of my 1.0 specification. a My invention relates totone arms 'adapted foruse in connection'with phonographs proj4 vided with tone chambers; that is, in connection with phonographs wherein the tone vor sound Yis conveyed from the reproducer through thetone arm and thereby transmitted into the 'tone chamber usually formed in the phonograph cabinet Ybeneath the record-Y`4 `holding turn-table.- 1 Y @ne object vof my invention is to tone arm wherein thejreprodu'cer receiving end or elbow isprovided with aV pivotal connection which will enable thepproper movement of the reproducer jacross the record gf permitting the reproducer to have the de- A sired freedom duringits travel and yet at the same time provide a connection which willnot interfere with the tonequalityand will not produce a blast or' permit any chatten soV often encountered with tonel arms and connections ,at present employed. f The means employed for providing the piv! otal connection just .referred tois of suchv nature as to take up any'slight diieren'ces in' formation or dimensions, within a given range', that may 'occur between therepro-V 4 freeswing orroscillation of the'tone Varm stylus or needle by the shallow grooves of the record.V The invention atthe same timeY contemplatesY a `constructionv wherein the tone arm proper may be; easilyy and quickly lifted or disconnectedfrom'its base or pivot providing portion; i I y The above enumerated objects',V as well as theadvantages inherent in the construction,

` fronti nnnvroa'rnoiioenlarns.

p I ing, wherein 2+ Chicago; in the countyof Cook and State of provide 'a 5 and thus provide a" construction responsive to the delicate power of force applied to the following detailed; description of the drawp Y 'I 1F igure l'-is afsideelevation vofi my im- :proved tone Varm Vshownirprovided with a r'ef producer, Vthe styluswhereof lis shown in con- 'tactgwith a-portion of a :disc record; the

mainV portion ofthe Vtone arm andits basev being shown'in longitudinal section to. di'sy Y close thepivot-forming' elements;- Y

Figure 2' is a perspective: view vof the'v mamportionof the tone arm 1n inverted po-VV sition, that is lookingat the bottom thereon `to disclosethe' interiorconstructionat the ends.

-Figure 3 is a perspectiveviewof thefbase or pivot-forming portionof the tone arm turned up on its Vside'.

Figure e is la sectional viewttaken on the l line L-t of Figure 1, looking 'in the direction lof thefarrows.

FigureY 5 is a. detail-sectional" view 'of a` -mpodifiedform of the pivotal connection be-Y tweenthe main portion of the tone arfm and1 the reproducer-receiv'ing end or elbow;

In the particularexemplicationfof invention asshown inthe clrawingthe main :l A Y portion ofthe tone arm shown at, l0 is p referably flared toward'the base thereof Vand given a substantially right angular bend atf85 a point intermediate of its'ends whereby the reproducer-receiving end will be maintained at proper elevation; Thelower or base end ofthe arm is provided with an internal web 1l, preferably of comparative width .and thickness, which may be Vsweated7 or other-- wise secured to Vthe Vtone arm,V Yas more clearly shown in Figure. AThe web 11, in its ypreferred ,form as shown in the eXempliflcationj is disposed dialnet!Y rically ofthe tone arm, with theV central part thereof Yenlarged or formed with ahub-portion as shown at 12l andprovided with a longitudinal socket 13' coincident 1 with the yvertical axis of the base portion -ofiO the tone arm. Thesocket 13 is of length suflicient to receive apivot-pin 14 f disposed upwardly' from thespider or web 15 ofthe base portion or collar 16 which latter is made separate from thetone arm proper. The

pivot pin *liisyof course, disposed at theV vertical axis of the base portion of the tone .arm and is provided witha tapered end 'or' point as 'clearly shown in Figures lV and-3,V Y.

y which extends into a tapered or `tlared socket formed in the bushing 17 placed'atithe upper end of the longitudinal 'socket'Y in the l"hub or enlarged portion 12pt web 11. As the tone arm and its web 11are usually made out ofV stamped orfcast'metahl .prefer to employ a A bushing 17. of sullicient hardness to provide a pivotal bearing which lwill not be affected bythe constant oscillations of the tone. arm.

The outer perimeteriofthe main portion of the tone arm 10, at the lower end thereof adjacent 7its orifice, 'isp'rovided with a segf' mental slo't or depression, as at 18, see Figure 2, which is intended to receive a boss 19 formedon the interior of the base yportionV or collar 16, see-Figure 3; -it being understoodY` that-the 'lower endf ot the main vportion of the tone arm extends int-o the base portion or ring '16 as shown in Figure .1, but with sutlicient play to permit free oscillatory movement ot' the tone arm and at the same time convey the tones orsounds into the tonechamber notshown. .The Vbase portion 16 is intended tobe secured to the top ofthe phonograph cabinet about the throat or oritice leading to the tone chamber and is 'therciiore provided with the horizontally disposed flange 20 which maybe secured by means of screws or otherwise to the cabinet.

The smaller or outer end ot the main portion yl() ot the tone armis shown bent or "curved laterally in a direction substantially .at right angles to the longitudinal axis' of the main portion of the tone arin. The oriticeY at this end is preferably made beveled or tlared,as shown at 21 in Figures 2 and 4e,

" tey receive the beveled vshoulder or portion 22 Vof the, reproducer-receiving connection or elbow 23 or' the tone arm andthus enable a smooth, flush connection to be provided between the main Aportion of the tone arm and said` elbow which will permit vertical oscillatory movement of said -elbow or reproducer' holder connection 23 of the tone arm. The end ofthe elbow portion 23 beyond the beveled portion or shoulder 22 is adapted to extend into the main portion of the` tone arm, as shown at 24 in. Figure .4, so as to pro-vide sufficient bearing or purchase and also ensure transmission of all pulsations `or vibrations from the reproducer to the main portionV of the tone arm;-

the tones or sounds being ensured free passage by providingy said end ,portion 2e with" a cut-away portion, as shown in Figure ft at 2da, which is disposedtoward themain part ottlietone armjwhen the elbow 23 is inb playing position.

'1n order to properly secure the reproducen holding end or elbow 23 to thevmain portion o't'the tone arm, 1 provide a pivot member or pin 25, adapted to `extend through the side wall ol: the elbow portion23 and into contact with. the inner or far side of the main portionbf the vtone arm; where .the

pin 25 isrpreterably taperedior pointed and.

extends into a suitable` bore yorlhole provided onlthe'inner wall ot' theniain'portiono the tone arm, as shown at 26 in Figure Lt. In

order to raintain.t he pro-perpivot .relation between the A pin 25. and "the inner "wall ofttithe main portiony of the tone arm at, 'the 'point '26, 1 `prcwidethe elbow portion23'-witha set-screw'27 disposed .transversely to pin V25 .and Yadapted to lhave .binding rrelation with pin 25 when set-screw 27 has been sufiL Ycientlyscr'ewedY down finto place.v ..Thefpin 25v extends: Vbeyond; the outeriwall of. `th'eelbow portion 23so.v as'.tti-receive.the-'endofaV bowed strap. .28. Tliez opposite. end-Qt .Strap-v strapin a directionlengthwiseot pin 25 may begmade-so as tofcompensate Vfor slight ditllerencesin' construction; or; thicknesses .of l

metal when `the Vrespective parts of the tone-f arm are being assembledIny order to preif;

vent any sidewise movement of the bracket' 28, 1 show the outer end ofthe main portion 10 of the tone arm provided withlugs or:l

` shouldersBl, see Figure 2,y spaced 'apart-a distance su'lticient-to receive'the strap 28 therebetween. The strap 28,-Vreceiv'1ng the outer end of pin 25,1 as shown in B`igure{1,4

.will maintain the portionsot'- the tone armv` in proper pivotalV relationuand also provide proper support for :the vertically oscillating port-ion Q1'k elbow wlilletl lSllOlllCleIS.3lY

will prevent sidewise mmfeinent,.'ofV thestrap4 2S. yAt the Sametime, the strap 28 will prof videA proper: support orrest. ;tor theA .elbow portion` 23 when thereproducer has been lifted and swunglbaclrfinto inoperative .pQL Y sition. ,i

1n Figure .5 1 i illustrate modifica-fv tion so tar as'the agivotal connection between the elbow or reproducer` holdingportion oiil the tone-arm and the main portion ofv the toneuarm is concerned. .1n this modi-z lied form, the'main portion 10 ot .thetone l arm .is provided with ai flared orifice the same asin the construction shown in Figure t, adapted to receive .thebeveled shoulder adjacent the end of the yelbow portion 23.; and the elbow portion is provided with apin 32, preferably removably securedA thereinV and disposed lengthwise of the y.end offelbow portion 23 so as tofcontactjwiththe"inneru wall att-he opposite or? fariside. of themain portionro theftone army` The pin 32'is shown held a in placeVV .means of. a setfscrew 2.7 which .pr.even ts moveinent ,ofthe pinin.

a directionflengthwisethereot andfthe outer;

end of the pin 32 is substantially H ush with the outer wallof theelbow portion23; with this outer end ofthepinprovided with a.

socket coincident with the longitudinaliaxis thereof adapted to receive the point of pivotforming screw or member 33 which is dis-Y posed through a suitablenut or washerl 3l and an' aperture in the bowed end of bracket 28.V Bracket 28 is secured to the main portionV lO'of the tone arm by the slot and screw' connection as in the construction shown in that disclosed in lFigure 4 in that the actual pivot for the reproducer receiving end orf elbow portion 23 is formed by means of pin 32 and pivot screw y; whereas in the construction shown in Figure 4 thepivotal connection for said sections of the tone arm is formed bythe pin 25 andthe inner wall of the tone arm section 10.

The construction shown in Figure 5 permits of adjustment of the pivotal connection without necessitaing the release of set-screw v 27 in its binding relation withthe pin. Both constructions, howeverenable a firm pivotal connection being formed between the respective sections of thertone arm so as to eliminate any chatter or vibration between the parts and yet at the same time permit free vertical oscillations of the tone arm section or elbow to which the reproduceris connected.

I have shown and described what I' believe to be the simplest and best adaptations of my invention, but modifications may be possible without, however, departing from the spirit of my invention.

waar nim 15;; f

. 35 I A phonograph tone arm comprising a main section havingfan outer laterally disposed end, the inner wall of said end, at the l j O e axis thereof,.being provided with--a'socketed -boss while the lower Vouter surface fis pro-V videdwith alpair of parallel spaced'lugs, a U Y Vreproducer receiving endor elbow having 1 Figure el. VThis construction differsV from? a reduced portion adapted to extend into the laterally Vdisposed end of the main section,V the elbow Vportion ofsaid end beingexternally provided `with anf apertuied boss' in axial alignment with the .socketv on the inner posed through said aperture Yin the elbow,

main section, ineanssecuredVv to said elbow .wall of the `main Section5 a pivotV pin dis'- `V for rholding thefpin against longitudinal Y' movement andfto induce said pin to' rotate with .the elbow, a bowed strap securedbewith said section so as' to *permitv adjustment lengthwisefof the strap, the other endof the strap being bent upwardlyv across theaxis of saidpivotV pin,` andra pivot providingfVVV Witnesses:

G. HEIDMANQ F. AQ

' BURR B. -BLoo-D.

551,' tweenfsaid spacedlugseon the' lowersurface 3 of the main section in adjustable relation

Images