US1775057A - Power-operated typewriter - Google Patents

Description

Sept. 2, 1930. R. G. THOMPSON POWER OPERATED TYPEWRITER Filed May 2, 1929 UPPER CASE fiflgo n D\REC.T\ON OF Hmmemficmp W S 3 Patented Sept. 2, 1 930 UNITED ,STAT'ES' PATENT oFFICE RUSSELL G. THOMPSON, OI ROCHESTER, NEW YORK, ASSIGNOR ELECTROMATIC.

TYPEWRITERS, INC., OF ROCHESTER, NEW YORK, A CORPORATION OF NEW YORK rownn-ornm'rnn 'rvrnwnrrna Applicationfiled May 2, 1929. Serial No. 359,950.

' tor, under the control of keys.

In machines of thekind, as in all ordinary typewriters, it is 'desirablethat the capital or upper-case letters be struck with "greater force than the small or lower-case letters, owing to the greater superficial area of the capitals. In a hand-operated machine this can be done by the operator, by striking the keys with greater force in writing capitals. In power-operated machines however, as ordinarily constructed, the force imparted to the type-bars is independent of the pressure upon the keys and is the same regardless of the,position of the case-shift.

The object of the present invention is to so construct a power-actuated typewriter that the upper-case characters shall automatically be struck with greater force than the lower;

case characters. 4

I have found that this can be accomplished very simply, in the case of a machine of the basket-shift type, by a relative position of ,parts such that the changes inangular position of a link connecting the type mechanism with the power mechanism, which changes are caused by the case-shifting movement of the type basket, result in the transmission of more force or power through this link in one case position than in the other.

In the accompanying drawings Fig. 1 is a partly sectional side elevation of typewriter mechanismernbodying the present invention, v the figure showing a single type bar, together with the mechanism immediately associated therewith. Fig. 2 is an enlarged detail from Fig. 1.

The invention is illustrated as embodied in a typewriter having the usual platen roller :5, and type bars 6. The type bars,of which only one is shown, are mounted on ,the usual pivot rod-,7, supported by a type basket indicated by: rear and front members. 8 and '9. The type basket is shown only diagram matically the rigid connection of thefor- Y ward and'rear members being indicated by dotted lines connecting them, in Fig. 1. p

The illustrated-machine is of the basketshift type, the normal or lower-case position being that in which the typebasket is elevated, and the upper-case position being reached by depressing the type basket. The means for shifting the type basket and for guiding. its movements are not shown, as they may be of any well known or suitable form, but the direction of the case-shiftin movement is indicated by the dot-and-dasfi line 1010. I p

The type bar 6 is actuated through the medeum of a toggle mechanism comprising a link 11 and a lever 12, which are pivotally connected together. The forward end of the toggle link 11 is pivoted on the basket member 9, while the toggle lever 12 is connected with the type bar, by means of a pivot 13. The toggle lever has a depending short arm 14, to which is connected a link 15 by which the toggle mechanism is actuated.

A spring 16, attached to the rear end of the toggle lever, tends to draw it rearwardly, in a direction to straighten the toggle, and this movement is limited by the engagement of theforward end of the toggle lever with a lateral lug 17 on the toggle link. In this normal position of the parts the toggle is substantially straight, and the type bar is swung forwardly into position to rest upon a cushion 18 on the basket member 9. This type bar mechanism is similar to that disclosed in my application filed February 11,

1928, Serial No. 253,727. and is therefore not.

claimed herein, but it is illustrated as it lends itself particularly well to an embodiment of the present invention.

The power mechanism, for moving the link 15 to actuate the type bar mechanism, may be.

of various forms known to the prior art, but is preferably of the type illustrated ii United States Letters'Patent No. 1,688,364 granted to me October 23, 1928. As its details are of no consequence in the present connection,-

.50 the position reached by them at the extreme which ispivoted, at on a stationary frame [member 23 of the machine. The cam is normally disengaged from the roller, but its operation is controlled by a key- 24:, mounted upon a key lever 25 which is pivoted, at 26, on a) stationary frame member 27. The arrangement is such that when the key is depressed the cam is causedto engage the power roller and make substantiall a half rotationin rolling contact therewith, thus causingthe vcam lever to be swung through an angle determined by the height oi?v the cam lobe. 'The lever is then free to return to its originalposition, with the cam arrested inposition to be I is accomplished may be similar tothose dis-.

the cam mechanism operatesthe bell-crankinto engagement with the platen. This operout ofengagement with the roller. .The details of the mechanism b which this result closed in the said, patent. p

The cam lever 21 isconnected, by a link 29, with a bell-crank lever 28, which" is pivoted at 26, and the upper armof thislever is. at-

tached to the link 15. Consequently, when lever is swung in the direction to pull upon the link 15, thus bending and shortening the? toggle mechanism and swinging the type bar ation of the arts is illustrated in Fig. 1,

- which shows-t em in the position of extreme movement of the cam lever.;

Since the bell-crank lever 28 is pivoted on a stationary frame member, the position. of the pivotal connection between the link 15. and this leveris always the same in any given" position of the cam mechanism. The posltion of the pivotal point of the. rear end of the link, however, is changed in consequence of the case-shifting movement. of the type basket. The' object of the present invention is accomplished by so designing the mechanisin, as toits dimensionsand the relative lo-. cations of the. various ivotal points, that this change hasthe resu t of causing a more powerful stroke to. be imparted to the type bar when the type basket is in its depressed or upper-case position. As shown particularly in Fig. 2, ,the jiangle between the line 10 -10 and the length of the link 15 is acute,

.in both the upper-case and the -lower-case positions. Thisfi'gures' shows the parts: in

' throw-of the cam mechanism, and the parts I position, and that in consequence, the-movev point results in a positive bending movement are shown, .in'fulllines, as in their uppercase position, while thed'otted lines show them as in the lower-case position. Itwill be apparent that in the upper-casepos tlon the angle between the line 10-610 and the link 15 is more acute than in the lower-case ment of the bell-crank lever-28 to a given of the toggle mechanism through a greater angle. If,'therefore,.the arrangement is such I that in the up er-case'position the type bar will be move positively into engagement p The invention claimed is:

with the platen, a shorter positive movement will be imparted to the typebar in the lowercase position, so that the stroke will be completed only' through the momentum of the' 'parts, against the opposition of the spring 16, and thus the impact of the type Wlll be less powerful. ,Assuming that the type bar,

determined by' its positive interconnect-ion witlithe. type-bar mechanism. Under these] conditions the cam will have its full or maxlmum eifective operation. When the arts are shifted to lower-case position the c ange in.

the location of the rear pivotal point of the link 15 will cause a slight forward movement of the upper arm of the bell-crank lever 28, with the result of movin the cam away slighly 'from the power rol er, so that when the cam is thereafter 'thrown into operation itwill impart a swing of; less amplitude to the cam lever, and henceto the type-bar mechanism.

1 A power-operated typewriting machine I comprising a shiftable type basket, a: typebar mechanism'carriedgthereby, a relatively stationary key-controlled power unit, and a' link connecting the power unit with'the type- *bar- I mechanism; characterized by the fact that the pivotalpoints. of theflink are, in both case-shift positions, in lines lying, with respect to the direction .of. the case shift, in acute anglesat thesanie side-eta right-angle position, so that in axgiven position of'the power-unit the pivotal connection-of the link withthe typeother case-shift position.

2. A power-o erated typewriting machine comprisin 'a's iftable type-basket, a typepivoted to and connectin the power unitand are, in both I case-shiftv positions of the type basket, in lines lying, with respect to t e direction of the case shift, in acute angles at the same side of a right angle, with the more,

acute angle corresponding to the upper-case position of the type basket; 7 i Y 3. A power-operated typewriting machine comprising a shiftable type basket, atype bar carried by the type basket, a relatively stationary key-controlled power unit, 1 and means, connecting the power unit with the ar mechanism ismore ad -vanced 1n onecase-shlft position than 1n the ins '1'15' i the toggle-mechanism; c aracterized by thev factfthat the-pivotal points of the pull-rod type bar, comprising a link of which one end is swung about the. pivotal point ofthe other 110 bar carried by the type basket, a toggle mechanis'm, for actuating the type bar, also carried 4 I by the type basket, 0. relativel stationary key-controlled power unit, an a pull-rod end in Consequence of a shifting movement of the type basket, the link being arranged, with respect to the line of shift, so that it forms, with said line, a substantially more acute angle in one case position than the other.

4. A power operated typewriting machine comprising a shiftable type basket, a platen, a type bar carried by the type basket, a key controlled lever pivoted on a fixed part for I actuating the type bar into engagement with the platen, and a link operatively connecting said key controlled lever and the type bar, the arrangement being such that the shifting movement of the type basket so changes the direction of the application of power to the type bar that it is impelled with greater force in one shift position than in the other. 5. A power operated typewriting machine comprising a shiftable type basket, a platen, a type bar carried by the type basket, a key controlled lever pivoted on a fixed part for. actuating the type bar into engagement with the platen, a link operatively connecting said 5 key controlled lever and the type bar, a

power driven ,roller, a cam normally free from said roller but movable into rolling engagement therewith, and a link operatively connecting said cam with said key controlled 3o lever, the arrangement being such that the shifting movement of I the type basket to upper' case position moves said cam to advallicethe point at which it engages the driven ro er. a RUSSELL G. THOMPSON.

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