US2501117A - Feed-roll release mechanism for typewriting machines - Google Patents

Description

March 21, 1950 H. c. YAEGER 2,501,117

FEED-ROLL RELEASE MECHANISM FOR TYPEWRITING MACHINES Filed Dec. 30, 1946 IN VEN TOR.

HARRY C YAEGER ATTORNEY Patented Mar. 21, 1950 FEED-ROLL RELEASE MECHANISM FOR TYPEWRITING MACHINES Harry '0. Yaeger, West Hartford, Conn, assignor to Underwood Corporation, New York, N. Y., a corporation of Delaware Application December 30, 1946, Serial No. 719,275

4 Claims. (Cl. 197-138l This invention relates to feed-roll release mechanisms for typewriters and the like.

In the regularly manufactured Underwood Standard typewriter the feed-rolls which engage the underside of the platen are collectively released by a crank or cam-shaft, which to perform its function, requires about one-quarter turn. See, for example, the patent to Helmond, No.

being shown. These frame ends 12 have a tierod I3 extending therebetween underneath the platen. On this tie- -rod l3 there are pivotally carried, at spaced locations therealong, a plurality of forwardly extending arms M, for supporting front feed-rolls l5, and a plurality of rearwardly extending arms 46 for supporting rear feedrolls ll. Springs 18 bear resiliently against 1,392,940. Prior to the present invention, the the underside of the arms l4 and IE to press the said cam-shaft was given a quarter turn by a feed-rolls l5 and i! into feeding contact with feed-roll release lever which was directly com the platen Ill. municative with a crank arm of said cam-shaft Below the tie rod 13 there extends parallel by means of a link. Due to the arcuate operating thereto a cam-shaft 2! which at several spaced path of the point of connection between said link p s e e g has pivotal support in hangers and the crank arm, the line of action of the link, 15 '2, rigidly carried on the e od O y ne of with respect to the crank-shaft, was of necessity these hangers being shown. unfavorably close to the crank-shaft axis at the The fo w y and w r y n in feedbeginning of the feed-roll releasing operation r011 Carrying ms l4 a d 6 constitute P s O when resistance offered to the turning of the levers including p ively also arms 23 and 24 crank-shaft was at a maximum. The initial ac- 2Q reaching downwardly in back and front of the tion or touch of the feed-roll release lever was Gem-Shaft 2 Sa d cam-shaft is formed with thus very harsh and objectionable. The harsh fiat faces 25 and 26 r oamming p ra ion with action suggested often that the feed-roll release the arms 23 and the arms 24, respectively- The was functioning improperly, and, in fact, it re-, arms 23 d 24 Stand normally Slightly O said sulted often in distortion, fatigue and breakage 25 cam faces as is Wn er t d in Figure 1, of the link or its operating lever. thereby to assure normally full-pressure feed- According to e invention, a twomart 1inkage ing contact. 'In order to effect release of the feedis provided between the feed-roll release lever T0115 from the platen, See igure 3., the camand the crank arm of the crank-shaft, and pro- Shaft is given approximately 90 ees turn. Vision is made so that the part of the linkage 30 During u m nt the -faces 25, 26 are which has connection with the crank arm will active to Spread the arms 24 d thereby act as an extension of the crank arm at the out lower the feed-rolis- It W ll be Seen that the set of the feed-roll releasing operation when the resistance to the turning of t e Shaft is greatest resistance offered to the turning of the crank- When 0am faces 25, 5 S art to act on the shaft is the greatest. Maximum leverage upon arms 23, 24 and that thereafter, the resistance the crank is thus had at the beginning of the against turning diminishes radually. feed-roll releasing operation and the leverage de- The Structure described to t s point is concreases thereafte ventional in Underwood machines and the in- 1; is therefore an Object of t invention t vention provides in association therewith an effiprovide a feed-roll release mechanism which is Fiehl? and easily p e echanism for turnoperable with ease and which mechanism is efilmg the -S t This mechanism comcient and simple in structure and peration. prises a feed-roll release handle 28 which has It is another object of the invention to provide P a Support up One Of the carriage ends I: an eflicient feed-roll release mechanism which on a Stud 30, the handle ng a branch 3-! acts with maximum leverage atthe beginning Wherefrom there depends pivotally a pitman 32. of the feed r 11 releasing peration and in Pivotal connection Of the branch 15 had the leverage decreases thereafter through a hole in the end 12- Referring now to the drawings: At the lower end of said .pitman, a short link 33 Figure 1 is a Sectional Side devation f a has pivotal connections at one end with said pit-, platen supporting carriage, as seenfrom th left man and at another end with a crank 34 which of the machine, and including the mechanism Preferably is formed as an integral bent-Off p of the invention in paper feeding condition 1710].). Of the crank-shaft 21. The normal rela- Figure 2 is a fractional front elevation of the tion 0f the parts is established y the abutment right l t n ,fram end seenin Figure I of a finger extension 38 of the 'pitman 32 with an Figure 3 is a View Showing some of the pal-ts 5 abutment 39. The crank 34 and the link 33 form seen in Figure 1 operated to release the feed-rolls. normally ayheht knee ch points downwardly,

Referring now to Figures 1 and 2 of th dr in a direction opposite to the feed-roll releasings, a cylindrical platen I0 is turnably supported ing t on of the pitman 32 which is in an up by means of a platen l II t th opposite nds ward direction. The link 33 is formed with a of the platen, in platen frame ends It, in a con- 6 transverse abutment shoulder '35 which is notventional manner, only the right hand frame-end mally in contact or virtually in contact with the crank 34 above its pivotal connection therewith, as shown in Figure 1, so that during initial feed-roll releasing motion given to the feedroll release lever 28, the link 33 moves as a leverage increasing extension of the crank 34, unitarily therewith. Preferably, the pivotal point of connection between the pitman 32 and the link 33 is normally at a point where a line from the crank axis is substantially normal to the initial line of action of the pitman 32. Moreover, said point of connection is preferably at a greater distance from the crank axis than the point of connection of the link 33 with the crank. Greater leverage is thus had for turning the crank-shaft at the beginning of the feed-roll releasing action. In the course of moving the feedroll release lever 28 from Figure l to Figure 3 position, the pitman 32 aligns itself with the link 33, and the alignment will prevail during a-later part of the feed-roll releasing motion, forthe reason that, as viewed in Figure 3, some capacity for the link to turn anti-clockwise with respect to the crank 34 is provided for by a slight trimming of the crank at 31. In effect, the link 33 functions as part of the pitman after it assumes aligned relation therewith. It follows thus that during the latter part of the feed-roll releasing motion the crank is turned by a line of action which is directly through the pivotal points of the pitman and the link 33. This provides that during the latter part of the feed-roll releasing motion the turning leverage for the crank 34 is reasonably maintained, it being noted that if the normal relation of the link 33 with the crank were maintained throughout the feed-roll releasing action, the direction of force would at the conclusion of the action be too closely in line with the axis point of the crank 34.

In Figure 3 the feed-roll release lever 28 is shown fully operated. The limit of operation of the lever 28 is determined by the upper edge of the frame hole 35, see Figure 1. In the Figure 3 position the feed-rolls are held in cast-off position inasmuch as the arms 23, 24 are then contacted by the peripher of the crank or camshaft 2|.

It will be noted that in the described structure the final line of action of the pitman 32 and the link 33 is nearlyat full crank-length from the crank axis, and that this is so despite the fact that the initial action is applied at somewhat more than crank-length from the said axis.

To restore the feedrolls, the release lever 28 is moved upwardly from its Figure 3 position and the link 33 will tilt away from the tie rod 13, the, motion being transmitted from the link 33 .via the abutment shoulder 36 which contacts the. trimmed portion 3! of the crank, the link being then moving unitarily with the crank. As the crank approaches normal position, the normal position stop finger 38 on the pitman is arrested but the crank thereafter turns a little further under the influence of the arms 23, 24 acting on the faces 25, 26 under the tension of'the springs l8, the final relation of the partsbeing then as shown in Figure 1. It will be noted that the restoration of the feed-roll mechanism is efiecte under favorable leverage conditions.

. What is claimed is:

l. The combination with a feed-roll mechanism comprising a feed-roll releasing crank requiringa rocking movement to release feed-roll means, of means to rock said crank, comprising, a feedroll release lever, a pitman operable by said lever, a link having apivotal connection with said crank and having another pivotal connection with said pitman farther from the axis of the crank than the first said pivotal connection, and means to cause said link to move for a first part of the feed-roll releasing movement as a leverage increasing extension of the crank, and to cause said link to move for a later part of the feedroll releasing movement as an extension of the pitman and no longer as an extension of the crank.

2. The combination with a feed-roll mechanism comprising a feed-roll releasing crank requiring not appreciably less than 90 degrees actuation to move feed-rolls from an applied to a released state, of means to actuate said crank, comprising, a manually operable feed-roll release lever, a pitman operable by said lever, a short link having a pivotal connection at one end with said pitman and having another pivotal connection at another end with said crank, said link and said crank forming normally a bent knee pointing away from the direction of feed-roll releasing action of the pitman, and abutment means oppositely on said link and said crank limiting pivotal motion of the link with respect to the crank in at least one direction and providing that the link constitutes a leverage increasing extension of said crank during an initial feed-roll releasing motion of said release lever, the possible pivotal motion of said link with respect to the crank permitting said link to assume and remain in an aligned relation with respect to said pitman during a later part of the feed-roll releasing motion, thereby to turn the crank without undue decrease of leverage which otherwise would result from continued swing of said link with said crank.

3. The invention set forth in claim 2, said abutment means limiting the pivotal motion of said link with respect to said crank also in the other direction to provide that reverse actuation of the feed-roll release lever will restore the crank.

'4. The combination with a feed-roll mechanism comprising a feed-roll releasing crank requiring not appreciably less than 90 degrees actuation to move feed-rolls from an applied to a released state, of means to actuate said crank, comprising, a manually operable release lever, a pitman operable by said lever, a short link having a pivotal connection at one end with said crank, being outreaching therefrom, and having a pivotal connection with said pitman at a point where a line from the crank axis is substantially normal to the initial line of action of the pitman, said link and said crank forming normally'a bent kneepointing away from the direc tionof "feed-roll releasing action of the pitman, and abutment means limiting pivotal motion of the link with respect to the crank in one direction soithat the link initially moves the crank as a leverage increasing extension thereof until the link assumes an aligned relation with the pitman, and functions thereafter as an extension of said. pitman to turn the crank at a not too -The following references are of record in th file of--.this patent:

g UNITED STATES PATENTS Number Name Date Smith Dec. 29, 1925.?

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