US2684145A

US2684145A - Typewriter type bar action

Info

Publication number: US2684145A
Application number: US267234A
Authority: US
Inventors: Laurence B Hill; George R Kunzelman
Original assignee: Smith Corona Inc
Current assignee: SCM Corp
Priority date: 1952-01-19
Filing date: 1952-01-19
Publication date: 1954-07-20
Anticipated expiration: 1971-07-20

Description

July 20, 1954 L. B. HILL ET AL 2,684,145

TYPEWRITER TYPE BAR ACTION Filed Jan. 19, 1952 4 She'ets-Sheet l LAURENCE B. HILL.` GEORGE RKUNZELMAN BY M July 20, 1954 L. B. HILL ET AI- TYPEWRITER TYPE BAR ACTION 4 Sheets-Sheet 2 Filed Jan. 19, 1952 GEORGE/p U. AroRs NEY July 20, 1954 1 B. HILL ET AL TYPEWRITER TYPE BAR ACTION Filed Jan. 19, 1952 FIC-P3 4 Sheets-Sheet 5 INVENTORS" LAURENCE B. HILL. GEORGE R.,KUNZELMRN AfToRNEY July 20, 1954 L. B. HILL ET AL TYPEWRITER TYPE BAR ACTION 4 Sheets-Sheet 4 Filed Jan. 19, 1952 INVENTORS LAURENCE B. HILL GEORGE RKUN L Patented July 20, 1954 UNITED STAT -ATENT y OF FICE TYPEVVRITER TYPE BAB! ACTION- Application January 19, 1952, Serial No. 267,234

20 Claims.

Thev invention relates to improvements in typewriter type bar actions and, more particularly, to

vkeydriven and spring returned actions for acnormally are cumbent and arrayed in an arc` which curvesupward from the middle to the sides of the system.

Ther keys ofthe system ci' individual operating actions for such a system of type bars are commonly arranged in stepped and straight banks or rows, usually four banks, which extend transversely of the typewriter at the front thereof. Such type bar and key systems present eX- tremely difcultproblems with respect to attainment of such desirable ends as smooth and like rapid accelerationofthe printing strokes of all ofthe type bars withsharp printing impact and quicktype bar return, uniform operatingdip or depression of all keys, uniformand light or easy starting touch for all keys, a like progressively increasing key resistance to nger depression by all keys, and a like final cushioning absorption of the momentum ,of a typists finger by each actuated key at the end of the printing stroke of its associated type bar.

The invention provides an improved system of type bar actions and improved individual type bar actions for the attainment of the foregoing primary ends and other ends hereinafter pointed out.

Theimproved type bar action system also is characterized by provision for uniform-operation of all of the type bar actions ona straight universal bar, by .an improved arrangement of two sets of `type bar action returning springs, byimproved means whereby the typist may vary the key touch at will, by its compact and inexpensive construction, and by its adaptability for use in a typewriter in which the type bars are pivoted in a case shiftable segment and in a typewriter in which the segment is disposed in arearwardly inclined plane for increased-visibility of `the writing line and to reduce the overall height of the machine.

In the accompanying drawings:

Fig. 1 is a fragmentary vertical sectional View of an otherwise known typewriter equipped with a system of type bar actions embodying the invention in its preferred form, the View being taken medially of the system of actions on the lineI-l vof Fig..2; i

Fig. 2 is a fragmentary topvplan view of the typewriter with-.certain parts omitted, ,and-others broken away, rfor clarity of' illustration'` of features Vof the invention;

Figs. 3 and 4 are diagrammatic views illustrating the operation respectively of one of the` type baractions at the middle'of the system and'one of the actions adjacent a side of the system, both of which actions have second bank operating keys;

Fig. 5 is a diagrammatic View on an enlarged scale four times that of Figs. 1 to 4 and illustratingthe system of returning springs for the key levers supporting the four different banks of keys;

Fig. 6 is adiagrammatic lView on the same scale as Fig. 5 showing how the .actions are varied in accordance with the key bank in which their keys arelocated;

Fig. 7 is a diagrammatic view on a scale three times that of Figs. 1 to 4 showing how the actions are varied in accordance with their locations between the middle and sides of the system; and

Fig. 8 is a detail sectional view on the line 8 8 of Fig. 1 showing featuresof lthe means variably settable Yby a typist to uniformly and simultaneously vary the touch of all of the keys.

The-improvements are shown embodied in a knownkind of typewriter having a type bar segment` which is disposed in arearwardly inclined plane, which normally is positioned for lower case. typing, and which is case shiftable downtypewriter having a type bar segment which is disposed in a vertical plane. So.y muchv of the known typewriter shown, as is necessary to a clear understanding of the inventionnow will be described.

The typewriter has aplaten roller Il) supported by a platen carriage (not shown) to travel end- Wise transversely of the typewriter above the rear portion of av stationary main frame of the typewriter. The main frame comprises vertically disposed left and right hand side plates Il and l2 and a rearwardly inclined cross plate I3 connected `to said side plates with the upper edge of the cross plate underlying the platen roller. A type bar segment I4, having the usual arcuate fulcrurn rod l5 about which the type bars I6 swing, and also having the usual radial guiding and spacing slots Il' for the type bars, is xedly heldin known manner toa rearwardly inclined and case-shiftable carrier plate or segment support I8.. located. at the front face of the cross plate. The. carrier plate, the segment and the type bar fulcrum rod all' lie in rearwardly inclined planes parallel to that ofthe cross plate I3, said planes in the machine-shown being inclined rearwardly at an angle of twelve and onehalf degrees to the vertical.

The carrier plate is supported, by means not shown, for downward shifting from its normal position shown in ig. l to a lower position in the same plane to condition the machine for upper case typing. The normal position of the carrier plate is determined by the engagement of a stop I9 with a stop lug 23 which projects rearward from cross plate I3. Stop ld is carried by a lug 2l which projects rearward from the carrier plate through a clearance aperture 22 in the cross plate. Downward shifting of the carrier plate is arrested by the engagement of a stop 23 with the stop lug 2! on the carrier plate, the stop 23 being offset laterally relatively to stop i9 and carried by a lug 2li which projects rearwardly from the cross plate.

The type bars l normally are supported in cumbent slightly upwardly and forwardly inclined positions in an arcuate array which is determined, as usual, by the arcuate fulcruin rod, by the radially slotted segment and by an arcuate rest 25 for the type carrying arms of the type bars. Said rest, as is usual in typewriters of the kind shown, is held to the segment carrier plate by a pair of side arms to shift with the carrier plate, one of said side arms being shown at in Fig. l. ln the typewriter shown, the rest 2d supports each of the type bars for a throw of 93 degrees from rest to printing position. The main type carrying arms of the type bars each carry a lower case type and an upper case type, and each type bar is extended rearward, as usual, beyond its fulcrum to form a type bar heel or short operating arm its for connection with an associated key-operated action which exerts a forward pull on the operating arm ltd to swing the type bar to printing position. The operating arms Hic are all of identical length and each makes the same angle with the type carrying arm of the type bar of which it is a part. The segment supports the bars, as is usual in the kind of typewriter shown, to print at a common printing point on a horizontal printing line which extends longitudinally of the platen roller somewhat above the level of the axial line of the platen roller. rhe two middle type bars of the system are located equidistant from the lowest point in the arc of the fulcrum rod l5 and from the medial vertical longitudinal plane of the machine containing the section line i-l in Fig. 2.

Certain features of the improved system of type bar actions which are known in the art rst will be described.

The heel of each type bar is connected by a pivot 2l with the rear end of a different one of a system of pull links 28, and the forward end of each link 2S is connected by a pivot 23 to the upper end of a different one of a system of sub-levers d@ of the third class. The sub-levers 33 are fulcrumed at their lower ends on a common straight and horizontal fulcrum rod 3l. Fulcrum rod 3l is held in a rear portion of a sub-lever fulcrum bar 32 which extends across the lower portion of the main frame below the system of type bars and is held to the main frame side plates il and I2 by screws 33, said rear portion of the bar being provided with vertical spacing slots 3d for the sub-levers 36. The two middle ones of the sublevers 36 of the System are located equidistant from the medial vertical longitudinal plane of the machine containing the section line l-l in Fig. 2, these two sub-levers being of equal length and 4 having their link pivot connections 23 equidistant from fulcrum rod 3 l.

The sub-levers 3d are graded progressively upward in length from the two middle sub-levers to the two side sub-levers of the system and the upper portions of the sub-levers are bent laterally to conform with the arc of the type bar heels, so that all of the pivots 29 lie in an arc which is concentric with the are of the type bar fulcrum rod and with the arc in which the pivots 2l lie. rihese arcs lie in parallel planes with the two pivots 2l, 29 of each link in substantially the vertical plane fore and aft of the machine. rlhe rear pivot 2l of each link is arranged to shif to points equal distances below and above a line normal to said parallel planes in case shifting the segment respectively from and back to normal position. The links 2S swing about their front pivots 2Q during case changing, and the distance between

pivots

2 and 29 is identical for all of these links.

First, second, third and fourth bank key levers 35a, 35h, 35C and 35d, respectively, of the system of key levers support the first, second, third and fourth bank type keys 33d, 35h, 35o and 35d, respectively, of the usual standard four bank keyboard. The key levers decrease in length from the first bank to the fourth bank, as usual, and all are fulcrunied at their rear ends on a common fulcrum rod lil' which is straight and extends horisontally across the machine. Rod 3l is carried by the upper portion of a key lever fulcrum bar which extends across the machine, which is held to the main frame side pla-tes by screws 3d, and which is provided with vertical spacing slots d for the rear ends' of the key levers. Adjacent the rear of the keyboard the key levers are spaced by a key lever guide comb lil which extends horizontally across the machine, which is held to the main frame side plates by screws 42, and which supports a straight horizontal cushioning stop 3, which stop extends transversely across the machine and normally is abutted by the upper edges of the key levers to determine their returned or rest positions.

The improved features of the individual type bar actions and of the system of said actions now will be described with reference to the preferred embodiment of the invention illustrated in the drawings.

To provide a more compact type bar action system located wholly forward of the intermediate across plate i3 of the main frame, the key lever fulcruin bar 38 preferably is located closely in front of the lower part of said cross plate and extends across the lower portion of the main frame below the system of type bar action links 28 and behind the sub-lever fulcrum bar 32. While the key lever fulcrum bar may be located adjacent the rear end of the main frame to there extend across the lower portion of the frame, as is more common in the art, the location shown is preferred notwithstanding the fact that it results in substantial shortening of the key levers, one advantage of the improved system being that it makes possible the successful use of short key levers while retaining a short uniform key dip and avoiding undue tilting of the keys on their printing strokes, as more fully hereinafter explained.

The sub-lever fulcrum bar 32 has a forward portion which carries a straight fulcrum rod ll-l that extends horizontally across the machine forward of and parallel to the fulcrum rod 3l and passes under the forward portions of the several type bars. Rod 44 is a common fulcrum for a gesamt 'second'system of sub-leversfwhich are levers of the rst'class andare engaged *in spacing slots 45 formedin said forward" portion of the vsublever' fulcrum bar. Each-offthese sub-levers is a bellcrank and,v in the normal rest positions of the type bar actions, one arm of each bellcrank extends rearward and upward from the bellcrank fulcrum rod andthe other arm extends forward and downward Vfrom said fulcrum rod. rIhese bellcranks are located behind the keyboard in a zone forward ofthe system of sub-levers 3l) and are spaced along their fulcrum'rod in accordance with the spacing of the sub-'levers 35i along their fulcrum rod.

Each bellcrank has its normally rearwardly and upwardly extendingarme 'connected to a different oner of the sub-levers 30 by aV different one of a system of 'normally rearwardly and upwardly extending pull links 41. These `links all are of identical lengths vand each link has a pivotal connection'll with a different one of said bellcrank arms 46 and a pivotal connection 48 with a different one of said sub-levers 35i, these pivotal connections being arranged as more fully hereinafter explained; For reasons hereinafter explained, the arms 46 of all of the bellcranks preferably are of identical size and shape and normally are in axial register across the machine.

Each key lever of the system of key levers is a lever of the second class; each key lever being connected intermediate its key and fulcrurn with the normally forwardly and downwardly extending arm of a different one of the system of bellcranks by a diiferent one of a system of pull links Eil. The pull links 50 all are of identical length, and each link has a pivotal connection l with a different one ofthe key levers and a pivotal connection 52 with' a different one of said forwardly and downwardly extending bellcrank arms. Each link 56 lnormally extends forwardly and upwardly from its pivotal connection 5| to its pivotal connection 52.

Preferably, and as shown, to save metal and still permit an arrangement of the sets of pivotal downward inclination, all of those bellcranks which are linkedv to the second bank key levers 35h have arms llbL of identical length and of identical normal forward and downward inclination, all of those bellcranks which are linked to the third bank key levers 35C have arms 46c' of identical length and of identical normal forward and downward inclination, and all of those bellcranks which are linked to the fourth bank key levers 35d have arms 46d of identical length and oi identical normal forward and downward inclinationy but the lengths of the arms 46a, 46h, 6c and dtd, and also their normal downward inclinations, are increased slightly in the order of recitation of said arms, arms 46a being the shortest and having the least normal downward inclination and arms 46d being the longest and having the greatest normal downward inclination. However, it will be obvious from the following description that all ofthe bellcranks of ie type bar action system may have those arms thereof which are linked to the key levers by the system of links Evalso formed of identical size and shape and located in axial -register across theisystemvinthe normal positionsrof the type Vthat of the bellcrankfulcrum rod Ml.

be such as to permit of the hereinafterdescribed arrangement Aof said arms and links and the link pivots.

In typewriters having a/system of graduated sub-levers of the third class connected by a'system of links to an arcuatesystem-of type bars to impart printing strokes of identical amplitude to' the-type bars, the angles of -throwof thesublevers must-decrease asthe lengthsof the sublevers increase, and yall ofthe pivots connecting said' links to the sub-levers must swing through arcs of identical chordallength. Since said` link pivots allv normally lie in a planeparallel lto that containing the arcuate fulcrum rod for the type bars,- theymust swing to positions ina second and' parallel' plane to complete the printing strokes of the type-bars. In the'machinefshown, link pivots 29 throw from the plane Pl tdthe plane P2, as indicated in Fig- '7, these planes ibeing parallel to that containing the type-bar Afulcrum rod and being inclined rearward at an angle of 121/2 degreesto the verticali. i An important feature of the invention resides in the arrangement of the bellcranks [i6-45a, the links 4l and the link pivots 43 and ein iaccordance with a principle by which there is provided a system of congruent toggles by which the sub-levers 30 and pivots 29 areA sov driven that all of the Apivots 29 vwill travelffrom'plane Pi to plane P2 in time intervals of'identical duration and at identical accelerating rates of speed in response to identical angular throws of the bellcranks at any 'singlespeed rate, and by which all of said toggles are connected to sublevers Sli .between their fulcrum and pivots f2s at constant leverage ratio points affording an identical-purchase -of all toggles on' said sublevers. The aforesaid principle now will be described with particular reference to the typewriter shown in the drawings wherein the togglesy exert a pulling action on the sub-levers to impart printing strokes to the type bars.

The link pivots 49 constitute the movable anchors of the toggles, and the link` pivots 4-8 constitute the hinge pivots connecting the toggle arms, which arms in turn comprise the links 4l andthe bellcrank armse, respectively. Arms le have a commoniixedly located pivotal anchor which comprises the bellcrank fulcrum rod M.' and is parallel to, and forward of, thevfulcrum rod 3l of the sub-levers Sil. The axes of the pivots 9 all lie on a cylindrical locus which is the periphery of ari-imaginary cylinder Cl whose axis is coincident with that of the bellcrank fulcrum rod 44. The pivots 4s normally lie on said locus at points between the sub-levers and bellcranks where the respective constant leverage arcs for the graduated sub-levers 30 intersect said locus, said arcs being struck about lthe sub-lever fulcrum rod 3l and some of them being indicated by the'reference letter A in Fig,k 7.- In the machine shown, a constant leverage ratio of a fraction under 3 to l is selected asdesirable, but of course a different ratio couldbe provided.v

The link pivots t8, or hinge pivots of the toggles, are all located on a second cylindrical locus which is the periphery of a second imaginary cylinder C2 whose axis also is coincident with To provide pull toggles, the radius of the cylinder C2 is smaller than that of cylinder Cl. Pivots 48 are located on the locus or cylinder periphery C2 Aat the points where-straight lines of equal length will connect the axes of eachpa'ifr' of pivots e8-'49,

By this arrangement, the eiective lengths of all links lll are identical and the effective lengths of all arms d6 are identical. Also the toggles will fold from congruent normal or starting conditions to congruent actuated or nnal folded conditions in actuating the sub-levers 35 to impart printing strokes to the type bars.

While an effective link length may be selected which is equal to the radial distance between the peripheries of the two cylinders Cl and C2, and thereby afford congruent toggles which normally are fully straightened and consequently normally would serve as anti-rebound toggle locks for the type bars, it is preferred to select a greater eifective link length, as shown, so that said congruent toggles will have congruent slightly folded normal conditions in which the hinge pivots are displaced identical distances forward and upward from straight lines connecting the movable and fixed anchorages of the respective toggles. The preferred normal condition of the toggles irnproves the key touch. Pushing toggles could be provided` according to the same principle by, for example, using a greater radius for cylinder C2 than for cylinder Cl, or by locating the axis 44 of these cylinders behind axis 3 l, as will be obvious from the above explanation ofthe embodiment of the principle in the typewriter illustrated in the drawings.

A further important feature of the invention resides in the arrangement of the key levers, the bellcrank arms lla, Lith, itc and lld, the links 59, and the link pivots 5I and 52 in accordance with a principle now to be described. These parts are so arranged that the links lill and pivots 5i and 52, and the portions of the key levers extending from link pivots El to the key lever fulcrum rod 3i' afford four sets or groups of toggles, one for each bank of keys, to actua'te the bellcrank arms Caa., 45h, llc and 6d to impart printing strokes to the type bars. On the down strokes of their acting keys these toggles act with rearward and downward pulling actions on the -bellcrank arms to which they are connected.

Each toggle includes a link 5G and that portion 0f a key lever which extends from the key lever fulcrum to the link pivot 5i, the link 5@ forming one arm of the toggle, said key lever portion forming the other arm of the toggle, the pivot 5l forming the hinge pivot of the toggle, the pivot 52 forming the movable anchor' of the toggle, and the key lever fulcrum rod 3l forming a xedly located pivotal anchor for al1 of the toggles and lying parallel to the bellcrank fulcrum rod tl.

The parts forming the said four sets of actuating toggles for the bellcranks are arranged so that the links 5B form toggle arms of identical effective length, that said key lever portions form toggle arms of identical effective length, and that all those toggles connected to keys in the same key bank are congruent toggles which have congruent slightly folded normal or starting conditions and which fold farther to congruent actuated or nal conditions on the down strokes of the keys. rlhe arrangement further is such that, although the lengths of the key levers vary in accordance with the banks in which are located the keys they carry, depression key strokes of like extent, like force and like speed will rock the bellcranks through like angles at like speeds and like rates of acceleration to effect complete printing strokes of the type bars, and that all of the keys will offer the same gradually increasing resistance to depression.

To the attainment of the ends just above set forth, al1 of the pivots 5l are connected to the key levers of the four

banks

35a, 35h, 35o and 35d so as to be equidistant from the key lever fulcrum rod Si' and normally to be in axial alignment across the machine. All of the pivots 52 have their axes normally located on a locus which is the periphery of an imaginary cylinder C3 (Fig. 6) whose axis is the axial line in which the pivots 5l normally are located. This locus intersects four constant leverage arcs Al (Fig. 6) which are of different radii and are struck about the axis of 'the bellcrank fulcrum rod 44. There is thus one of said arcs for each bank of keys.

The links 5G connected tothe first bank key levers 35a have their pivots 52 connected to the bellcrank arms 56a to swing in that one of the arcs Al having the shortest radius, the links 50 connected to the second bank key levers 35h have their pivots 52 connected to the bellcrank arms lh to swing in the next succeeding one of the aros Al, the links 53 connected. to the third bank key levers Sile have their pivots 52 connected to bellcrank arms itc to swing in the next succeeding one of the arcs Ai, and the links 5i? connected to the fourth bank key levers 35d have 'their pivots 52 connected to the bell crank arms 8d to swing in arc Al having the longest radius.

All toggles of any group connected to key levers carrying keys in the same bank thus have congruent slightly folded or downwardly broken normal or starting conditions, the toggles in the group connected to the first bank or longest key levers being normally folded more than those in the other three groups, the extent of normal fold decreasingl from group to group of toggles connected to the second, third and fourth bank key levers 35h, 35e and 35d in the order just recited. The toggle hinge pivots 5i are each carried downward and rearward upon depression of its connected key lever on a cylindrical locus which is the periphery of an imaginary cylinder C4 (Fig. 6) whose axis is coincident with that of key lever fulcrum rod 3l, the extentl of such movement being the same for all toggles connected to any one bank of key levers, and being least for rst bank key levers and increasing from bank to bank for the second, third and fourth bank key levers. The additionally folded final or actuated conditions of all toggles of any group connected to key levers of the same bank are congruent but the extent of added folding Varies with the key lever banks to which the group of toggles are connected, being least for the toggles connected to first bank key levers and increasing from key lever bank to key lever bank for toggles connected to the second, third and fourth bank key levers.

By the above-described arrangement the key purchase on the bellcranks through the medium of the bellcrank actuating toggles progressively decreases on the down strokes of the keys since the links 5t on said strokes move nearer into parallelism with the bellcrank arms to which they are pivoted. The key purchase on the bellcranks through the medium of said toggles also is the same for all keys regardless of the banks in which they are located, since the toggle purchase on the bellcranks varies for each bank of key levers in direct proportion to relative lengths of the key levers of different banks, such toggle purchase being least for the rst bank, or longest, key levers and increasing for the second, third and fourth bank key levers.

From the foregoing description it will be obkey is depressed. As indicated in Figs. 3

.l 9 served that, as indicated in Figs. 3 and 4, a full depression of any type key at a constant rate will actuate the sub-lever 30 connectedv to said key, and consequently the type bar connected to that sub-lever, at a speed which accelerates throughout said key depression. It also will be observed that the rear portion of the actuated key lever acts through connected link 59 to impart an accelerated throw to the conne ted belcranhand that this acceleration is greatly augmented by the accelerating action of the arm 45 of the bellcrank and the link 41 which connects it to the sub-leVer'Sll. This compound,y cr two-stage, acceleraton assures a high speed type impact even for a relatively slow and easy depression of the key and thus enhances-the clarity of the type irnpressions and permits the making of a maximum. number of good carbon Copies with a minimum key depression effort. lt further contributes to successful use of short l-:ey levers with short key dip, since the extent of angular drive' of any sublever 3i! per equal increment of key dip is progressively and grcatly augmented as its actuating and 4, depression of a key at a constant rate and in, for example, four equal steps, will cause the actuated bellcrank to rock through four progressively increasing steps and will cause the actuated sublever E@ to rock through four still greater and progressively. increasing steps. The normal and final positions of the actions shown :in Figs. 3 and 4 are indicated respectively in full lines and in dotted lines, and the termini of the iirst, second and third steps of movement of the key, bellcrank and sub-lever .30 are indicated by correspondingly numberedr short lines.

Further features of the invention comprise the two sytems of returning or retracting springs for the system of type bar actions, and the provisions for adjusting the normal tension of the springs of the two systems.

Different springs 53 of a system of helical tension springs of identical size, length and inherent power constitute the primary retraction springs for the type bar actions. tend fore and aft of the machine parallel to the medial fore-and-aft vertical plane of the inachine, have their rear ends hooked in anchor holes E@ in the rearwardly inclined upstanding flange portion 55o of a spring anchor bar 55, and

have their forward ends hooked in anchor holes 5S in the respective euh-levers it@ below the laterally vbent upper portions of the sub-levers. Flange portion tichas arcuate upper edge curved upwardly from its middle to its ends with the holes adjacent said edge and equidistant therefrom. The anchor holes 5d all are located in one and the anchor' holesli all are located in a second arc. These arcs have the saine radii, lie respectively in planes P3 and Ft (Fig. 7) parallel to piane Pi, are concentric with the arc inv-nich lie the pivots 2t at the upper ends of sup-levers and have their lowest points in the `medial fore-and-aft vertical plane of the typewriter. The twofanchor holes 56 for any one sprinfr 53 occupy like positions in the arcs in which the respective holes are located, the holes 5t being spaced according to the spacing of the lor-fer portions of the sub-levers By the aforesaid arrangement of the system of springs 53, all of said identical springs have the sametension in the retractedpositions of the type bar actions7 have their anchor holes t6 arranged to shift from plane Ps to a second and parallel plane P5(Fig. 7) through arcs of like The springs 53 all eX- chordal lengths to stretch the-springs like extents on the printing strokes of the type bars, and have their anchor holes 56 arranged relatively to the sub-lever fulcrum rod 3i at constant leverage ratio points for application of like effective power to the sub-levers. On the printing stroke of any type bar, the stretching of the retracting sprinfy 53.01? the actuated type bar action is accelerated in direct proportion to the acceleration of the type bar so thatthe accelerated acquisition of kinetic energy by the type bar aids the stretching of the spring in such manner that a substantially constant resistance to key depression is offered by the spring which contributes to ease and lightness of the key touch.

While the spring anchor yloar may be xed immovably to the main frame of the typewriter, it preferably is mounted for adjustment by the means shown intol different selected positions to permit a typist to vary at will the normal key touch by varying simultaneously and uniformly the extent to which all of the springs 53 are stretched in the normal returned positions of the type bar actions.

To permit such adjustment of the normal stretch of springs 53, the anchor bar 55 is supported for adjustment in a path which is normal to the planes PI, P2, P3, P4 and P5 (Fig. '7) thereby to shift the spring anchors 55, while maintaining them in a plane parallel to the planes Pfl and Ps in which the spring anchors 56 lie in the normal and actuated conditions respectively of the type bar actions. To so support and adjust the anchor bar the following described means are provided, said `means being shown in Figs. 1, Zand 8 and set for minimum key touch.

Extending fore and aft of the typewriter, and riveted, or otherwise xed, to opposite ends of the anchor bar 55, are two end bars 5l having in their rear ends slots 53 which extend normal to the planes Pl, F2, P3, Pd and P5 (Fig. 7) and also to the plane of flange portion 55a of the anchor bar. The key lever fulcrum rod 3l eX- tends through slots 53 to support the end bars El at their rear ends to shift in the aforesaid path. To prevent lateral shifting of the slotted rear ends of the end bars, they are guided in slots 59 (Fig. 2) in the key lever fulcrum bar 3d. To support the forward ends of the end bars to shift in said path, and to aiford ready detachment of the anchor bar with its end' bars, there is provided a rock shaft S6 which extends horizontally across the typewriter and has reduced ends toc, and there are provided a pair of bearing brackets Si which are xed to the sub-lever fulcrum bar 32 and in which the reduced ends of said shaft are journalled, a pair of upstanding rock arms 62 and 63 iixed to said shaft, a pair of headed pivot studs 61% xed to said rock arms equidistant from said shaft, and a pair of rearwardly extending slots 55 in the forward ends of the end bars 5l in which said studs 64 are engaged. Slots e8 and 65 are open at the adjacent ends of the end bars til to permit ready demounting of the anchor bar.

The springs 53 urge the anchor bar forward to maintain the studs 4 at the rear ends of slots Se. The rock arms S2 and 53, and the headed studs 64, prevent lateral shifting of the forward ends of the end bars 5l of the anchor bar. The shaft is rockable to swing the rock arms 52 and 63 downward and rearward dieren't distances from their limit position shown in the drawings and to carry the studs Gil rearward and downward in 1l a path substantially parallel to slots 58 and sub stantially normal to the planes Pi, P2, P3 and Pf3.

To enable the typist to rock the shaft and rock arms, and to latch them in different selected positions to maintain the anchor bar in selectively adjusted positions, the left hand rock arm s2 is extended upward to a point adjacent the top of the typewriter and is formed at its upper end with a finger-piece or handle portion 52a. rfhis nger-pieceextends through a foreand-aft slot Sii formed in a bracket 8l, this bracket being fixed to the top portion of the left hand Vside plate ii of the main frame. Arm Q2 is a sheet metal arm having sufficient inherent resilience to maintain finger-piece 62a releasably latched in any desired one of a series of notches formed in the bracket 5i' along the right hand edge of slot t5, Vthe bracket shown having five notches with the setting indicating numerals l, 2, 3, 4 and 5 provided on the bracket opposite the respective notches. Preferably, arm 522 is formed with a bent portion B2b which contacts the inner face of the main frame side plate i I intermediate the bracket 6i and the stud 64 which is carried by said arm. This arrangement permits resilient flexing of the portion of the arm 62 above said bent portion @2b to unlatch the nger-piece 52a without straining or bending the end bar 5l with which said stud 6ft on arm 62 is engaged. rThe end walls of slot 66 in bracket 61 are abuttable by the finger-piece to determine the limits of adjustment of anchor bar 55. In the position shown, the bar 55 is adjusted for light touch and anchors springs 53 so that they are slightly stretched while the several type bar actions are in normal returned condition.

The system of auxiliary type bar action returning or retracting springs 68 is provided to insure quick and full retraction of the key levers into contact with the key lever stop d3 and to insure normal maintenance of contact of the key levers with the stop. The auxiliary springs 68 are constructed, arranged and anchored as is now to be described for action of all of the springs with like effective force on the key levers and for simultaneous and uniform adjustment to vary their effective force. For over-all lightness of key touch, it is preferable to use springs 68 of a minimum force sufficient to slightly more than counterbalance the eifect of gravity on the key levers.

Springs 68 are helical coil springs all of the same size, strength and length. Each spring is hooked at one end in an anchor hole 69 in the key lever it is to return, and is hooked at its other end in one of a series of anchor holes 'lil in an adjustable spring anchor bar li. Anchor holes "it are arranged in a horizontal row across the typewriter adjacent the upper edge of anchor bar 'Il and are spaced in accordance with the spacing of the key levers. The springs 63 extend downward and rearward from holes 'i0 to holes t9. With the type bar actions all in normal position, the anchor holes 6@ are so arranged that all holes 59 in key levers carrying keys in the same bank are in axial register in a row across the typewriter, but the four rows of holes for the four diiferent banks of

key levers

35a, 35h, 35e and 35d are arranged progressively closer to the key lever fulcrum 3l in the just w recited order of said banks of key levers, as indicated in Fig. 5.

All four rows of holes t9, in the normal returned conditionY of the system of type bar actions, are located on a cylindrical locus C5 (Fig. 5) the axis of which is the line on which the row of holes 'l0 is located. Said rows of holes 69 are equally spaced on said locus in direct proportion to the respective effective lengths of the banks of key levers and are so located on said locus that a straight line can be drawn from the line of the row of holes 'lil which will be normal to a chordal line of said locus and will intersect the locus midway between the rows of holes 69 in the nrst and fourth bank key levers and midway between the rows of holes 69 in the second and third bank key levers.

in the machine shown, the anchor bar il extends across the typewriter between the key lever fulcrum bar 38 and the sub-lever fulcrum bar 32 in a rearwardly tilted position aiording a compact arrangement of these bars. While thc anchor bar 'ii may be fixedly supported in various ways, it preferably is supported for slight adjustment of the position of the row of anchor holes it in a path at least substantially normal to a chordal line of the locus of the rows of holes 59 intersecting the two outermost rows of holes 9 which path will, of course, be normal to a chordal line or the locus intersecting the two innermost rows of holes 6s. For this purpose the rearwardly tilted anchor bar is provided along its lower edge with a forwardly projecting flange Ha the straight front edge of which is rockably seated in a horizontal groove or channel 'i2 formed in the rear face of the sub-lever fulcrum bar 32. Adjusting and retaining screws 'i3 pass loosely through holes lli in bar il and are screwed into holes tapped into the fulcrum bar 32 at the rear face of bar 32, By screwing the screws 'i3 more or less into said holes, the anchor bar may be rockably adjusted. Springs 58 will maintain the anchor bar rocked against the heads of screws 13.

A further feature of the system of type bar actions above described resides in the fact that it affords means for imparting uniform strokes to a straight universal bar for actuating a ribbon vibrator. Afstraight universal bar i5 depends from, and is fixed on, a rock shaft 'i5 which journalled at Ti in side plate ii and is journalled at 'i8 in a bracket 'it xed to side plate l2. A rock arm Sii xed on said shaft carries a universal bar return stop 8i which normally en gages a stop finger 82 on bracket 19. A universal bar return spring 83 is attached to a rock arm 84 fixed on the shaft. The spring normally holds the universal bar rocked into Contact with the rounded upper ends Lite of the bellcrank arms iii with stop ill engaged with stop iinger 32. Rock arm 84 is connected by suitable linkage (shown in part at 85) to a ribbon vibrator (not shown) to actuate the vibrator at the type strokes.

We claim:

l. In a typewriter, a type action comprising a pivoted front strike type bar, an upstanding sub-lever of the third class connected at its upper end to the type bar to swing the bar into printing and rest positions, a sub-lever of the nrst class forward of the third class sub-lever, a fore and aft extending key lever of the second class carrying its key at its forward end, said sub-levers and key lever having their respective fulcrum axes extending horizontally across the machine in parallelism, a link connecting the third class sub-lever between its ends with one arm of the first class sub-lever to form with said arm a normally extended toggle arranged to fold to exert a continuously accelerating pull on the third class sub-lever throughout the`printing strokes of the type bar, and a link connecting theothcr arm of thefirst class sub-lever with the key lever forward of the keylever'fulcrurn axis `and second arms extending from a pivot parallel to that of the key lever, a nrst link connected by transverse horizontal pivots to the key lever and the rst arm of said iirst sub-lever, a second sub-lever extending upward from a pivot between and parallel to those of the key lever and iirst sub-lever, a second link connected by transverse horizontal pivots to the second arm of the rst sub-lever and to the second sub-lever be tween the ends of the second sub-lever, a front lstrike type bar pivotally mounted in the :typewriter and connected with the upper end of the second sub-lever to be swung throughra printing stroke of fixed length by downward rocking of the key lever, and spring means for restoring the aforesaid parts to a normal condition of rest in moving from which, into a condition in which the type bar is in printing position, the first link `becomes decreasingly inclined to the key lever f and increasingly inclined to the first arm of the rst sub-lever while the secondlink becomes decreasingly inclined to the second arm of the first sub-lever.

3.In a typewriter, a type action comprising a key lever and first and second sub-levers each rockable aboutV a different one of three parallel horizontal fulcrum axes which extend transversely of the typewriter, said first sub-lever having rst and second arms and said second sublever vhaving a single and upstandingfarm, va first link connected by horizontal transverse pivots to the key lever between the key and the fulcrum axis of the key lever and to the rst arm oi the iirst-sub-lever, a second link connected by horizontal pivots to the second sublever between the upper end and the fulcrum axis of that sub-lever and to the second arm of the first sub-lever, and a normally cumbent front strike pivoted type bar having a type carrying arm and a heel portion-, athirdilink having a forward end pivotally connected to'the upper end of the second sub-leverl and a rear end pivotally connected to the heel portion of the type bar, the pivots of the rst link being so arranged that a normal inclination of said link to the key lever decreases and a normal inclination of said link to the rst arm of the first sub-lever increases throughout printing strokes of the type bar in response to downward rocking movements of the key lever, and the pivots of the second 'link being so arranged that a normal inclination of said link to the second arm of the rst sub-lever decreases throughout printing strokes of the type bar in response to downward rocking movements of the key lever.

4. A typewriter, as claimed in claim 3, wherein the type bar carries lower and uppercase type, and wherein means are provided for bodily case shifting the type bar relatively to said key lever and to the two sub-levers into positions for lower Cil .ably connecting the key levers supporting keys and 4upper case typing, in both of which positions the pivotal connection of the third link with the heelportion .of the type bar is equidistant from the pivotal connection of said link with the upper end of the second sub-lever.

5. A typewriter having a system of type actions which comprises a system of type keys arrayed across the typewriter in a plurality of fore and aft spaced and horizontal transverse rows, a system of key levers carrying said keys and extending rearwardto a common straight and horizontal transverse fulcrum axis, a system of sub-levers ulcrumed at one end of each sublever to rock about a common fulcrum axis parallel to that of the key levers, said sub-levers vincreasing in length from the middle to the sides of the sub-lever system and having their other ends normally arrayed in an arc across the typewriter, a system of pvoted type bars normally arrayed in an arc concentric with that of said other ends of the sub-levers and connected with said ends for movement through like printing strokes to a common printing point, a system of congruent and parallel toggles extending from the sub-levers to a common fulcrum axis parallel to those of the key levers and sub-levers, said toggles having hinge pivots and anchoring pivots to the sub-levers which are equally spaced and respectively normally located on different ones of two cylindrical loci concentric with the toggle iulcrum axis, said anchoring pivots of said toggles being connected to the sub-levers at univform leverage points, and connections between the respective key levers and toggles for actuating the toggles to the same extent in sub-lever accelerating direction by equal depressions of the respective keys to drive the respective type bars through complete printing strokes.

6. A typewriter having a system of type actions which comprises a system of key levers extending orward from a straight and horizontal .transverse fulcrum axis and supporting their keys in fore and aft spaced transverse rows, a system of normally cumbent and forwardly extending type bars pivotally supported in an .parallel to that of the key levers, a system of links each having a pivotal connection with one arm of a diirerent one of the iirst class sublevers and a pivotal connection at a constant leverage point with a diierent one oi the third class sub-levers, the two pivotal connections of .all of said links being equally spaced and aru ranged on diiierent ones or" two cylindrical loci .which are concentric with the iulcrum axis of the rst class sub-levers, and a system of links variin diierent rows to the other arms of said iirst class sub-levers to rock those sub-levers through angles of the same amplitude per unit depth of key depression.

i7. A typewriter having a system of front strike type actions comprising a system of key levers extending forward in the typewriter from a straight and horizontaltransverse iulcrum axis and presenting'fore and aft spaced horizontal rows of keys parallel to said axis, a system of upstanding sub-levers of progressively increasing heights from the middle to the sides of the system and having a horizontal fulcrum axis at their lower ends parallel to and forward of that of the key levers, a system of pivoted front strike type bars connected with the upper ends of the sub-levers to be swung through printing strokes of identical amplitude by forward movements of the upper ends of the sub-levers through arcs of identical chordal amplitude, a system of congruent toggles radiating from a xedly located fulcrum axis parallel to and forward of those of the key levers and sub-levers to pivotal connections with said sub-levers located at uniform leverage points on the sub-levers and on a cylindrical locus concentric with said fulcrum axis of the toggles, all of said toggles normally being identically and substantially fully straightened, and means connecting the key levers and toggles for folding of the toggles identical extents by identical depression strokes of the keys.

8. A typewriter, as claimed in claim 7, wherein the means connecting the key levers and togy gles includes means for equalizing the initial purchase on the toggles of keys in different key rows.

9. A typewriter, as claimed in claim 8, wherein the means connecting the key levers and toggles further includes means to progressively olecrease the key purchase on the toggles through the depression strokes of the keys.

10. A typewriter having a system of front strike type actions comprising a system of upstanding sub-levers having their upper ends arranged in an arc which curves upwardly from the iniddle toward the sides of the typewriter and having at their lower ends a common straight and horizontal transverse fulcrum axis, a system of pivoted front strike type bars connected with the upper ends of the sub-levers to be swung through printing strokes of identical amplitude by forward movements of the upper ends of the sub-levers through arcs of identical chordal amplitude, a system of congruent toggles each having first and second members connected by a hinge pivot, the first members of the toggles having a ixedly located common fulcrum axis forward of and parallel to that of the sub-levers and having extensions forward oi their fulcrum Y axis, the second members of the toggles having pivotal connections to the sub-levers at uniform leverage points on the sub-levers which normal- 1y are located on a cylindrical locus concentric with the fulcrum axis of the first toggle members, the hinge pivots of the toggles normally being located on a second smaller cylindrical locus concentric with the first mentioned locus, a second system of congruent toggles having pivotal connections at one end to said extensions of the first toggle members of the other system of toggles and extending rearward therefrom to a common xedly located fulcrum axis parallel to that of said first members of the other system of toggles, and a system of type keys carried each by a diiferent toggle of said second system of toggles for folding the latter toggles as the keys are depressed.

l1. A typewriter, as claimed in claim 10, in which the keys are arranged in fore and aft spaced straight and horizontal rows, and wherein the pivotal connections of the toggles of the second toggle system with said extensions of the rst toggle members of the other toggle system are arranged to decrease the normal initial purchase of said toggles on said extensions in accordance with the increase of the distance of the key rows from the rear one to the front one of said rows from the fulcrum axis of the toggles of the second system and also to progressively decrease the initial toggle purchase on said extensions throughout depression strokes of the keys.

12. A typewriter having a system of front strike type actions comprising a system of first, second, third and fourth bank key levers of the second class, a system of fore and aft extending sub-levers of the first class, a system of upstanding sub-levers of the third class increasing in height from the middle to the ends of the system, means affording common straight and hori- Zontal transverse fulcrum axes for the three lever systems with the axis for the system of upstandng sub-levers intermediate those for the key levers and the fore and aft extending sublevers, a iirst system of links of identical lengths having pivotal connections with the upstanding sub-levers and the rear arms of the fore and aft extending sub-levers, the pivotal connections of said links with the upstanding sub-levers being located at uniform leverage points on said sub-levers and on a cylindrical locus concentric with the axis of the fore and aft extending sublevers, the pivotal connections of said links with the rear arms of the fore and aft extending sub-levers being located on a smaller and concentric cylindrical locus, a second system of links of identical lengths having normally axially aligned pivotal connections with all of the key levers and having pivotal connections with the forward arms of the fore and aft extending sub-levers which normally are axially aligned for those links connected to any one bank of key levers but which normally are located at distances from the fulcrum axis of the fore and aft extending sub-levers which increase for links connected to each bank of key levers following the first bank, and a system of pivoted front strike type bars connected with the upper ends of the upstanding sub-levers to be swung through printing strokes by depression strokes of the key levers.

13. A typewriter, as claimed in claim 12, wherein the type bars are connected to the upstanding sub-levers by links of like lengths, and wherein the system of type bars is mounted for case shifting movements relatively to the three lever systems.

14. A typewriter, as claimed in claim 12, wherein the two systems of sub-levers and the two systems of links both extend across the typewriter and below the system of type bars, the fulcrum axis of the key levers extends across the typewriter and below the system of type bars, and the keys of the four banks of key levers extend in rows across the typewriter adjacent the system of type bars.

15. A typewriter, as claimed in claim 12, having a system of type action returning springs of like lengths and power anchored at one end to the upstanding sub-levers at uniform leverage points on said sub-levers and normally extending parallel to each other, and also having means stationarily anchoring the other ends of said springs, the anchored ends of the system of springs normally lying in two parallel planes.

16. A typewriter, as claimed in claim 15, havhand lever adjustable means for shifting the plane of the stationarily anchored ends of the springs toward and from the plane of the other anchored ends of the springs and in a path normal to the latter plane.

17. A typewriter, as claimed in claim 16, having for the key levers a system of counterbalancing springs of like length and power which are stationarily anchored on a line .parallel to the fulcrum axis of the key levers and are an- Choi-ed to the respective banks of key levers at points on a cylindrical locus concentric with said line, the spring anchor points to the key levers Y of different 1oanks approaching the key lever axis in order from the rst to the fourth bank key levers.

18. In a typewriter, a system of front strike pivoted type bars supported for identical printing strokes from normally cumbent positions in an arcuate array of said bars that rises toward the sides of the machine, a system of type key levers extending rearward from a multiple row keyboard to a straight and horizontal transverse key lever fulcrum axis, a rst system of sub-levers upstanding from a fulcrum axis par-- allel to that of the key levers and having their upper ends arrayed in an arc concentric with that of the type bar array, means connecting the upper ends of said sub-levers with the type bars to swing the type bars through printing strokes and return strokes, a second system of subdevers having front and rear arms extending from a rulcrum axis forward of and parallel to that of the first system of sub-levers, a system of links having identically spaced horizontal pivotal connections with the upstanding sub-levers and the rear arms of the other sub-levers, said pivotal connections being located on two cylindrical loci which are of different diameters and are concentric with the fulcrum axis of the second system of sub-levers, the pivotal connections with the upstanding sub-levers being located on the locus of greater diameter and at uniform leverage affording points on said upstanding sublevers, connections between the key levers and the forward arms of the second system of sublevers for rocking said arms downward by depression strokes of the key levers, the rear arms of the second system of key levers being of identical size and shape and normally being in register across the typewriter, and a straight universal bar extending across said identical sublever arms and supported for actuation by said arms on depression strokes of the key levers.

1S. A typewriter having a system, of type actions comprising a system of upstanding sublevers rockable about a common straight horizontal fulcrum axis which extends transversely of the typewriter with the upper ends of the sublevers normally arrayed in an arc which curves upwardly toward opposite sides of the typewriter, a system of pivoted front strike type bars connected with the upper ends of the sub-levers to be swung through printing strokes of identical amplitude by forward movements of the upper ends of said sub-levers through arcs of identical chordal amplitude, a system of congruent parallel toggles extending from a common fixed fulcrum axis which is forward of and parallel to that of the sub-levers to pivotal anchorages which are located at uniform leverage points on the respective sub-levers, said toggies normally being in identically extended conditions in which their hinges are located on one cylindrical locus concentric with the toggle fulcrurn axis and their anchorages to the sub-levers are located on a second and concentric cylindrical locus of larger radius, and a system of depressible keys connected with the respective toggles to swing the toggle hinges upwardly and forwardly about the toggle fulcrum axis on the depression strokes of the keys to impart printing strokes to the type bars.

20. A typewriter having a system of type actions comprising a system of upstanding sublevers rockable about a common straight horizontal fulcrum axis which extends transversely of the typewriter, said sub-levers having their upper ends normally arrayed in an arc which curves upwardly toward opposite sides of the typewriter, a system of pivoted front strike type bars connected with the upper ends of the sublevers to be swung` through printing strokes of identical amplitude by forward movements of the upper ends of said sub--levers through arcs of identical chordal amplitude, a system of congruent and parallel toggles having a common xed fulcrum axis parallel to the sub-lever axis, said toggles normally being identically and substantially full straightened and having pivotal anchorages to the sub-levers at uniformi leverage points on the respective sub-levers which normally lie on a cylindrical locus which is concentric with the xed fulcrum axis of the toggles, a system of key levers which extend forward from a fixed fulcrum axis parallel to that of the toggles and support a plurality of fore and aft spaced rows of keys at the front of the typewriter, and a system of individual connections between the key levers and toggles for folding the toggles identical extents at identical accelerating speed rates by depression strokes of the keys of identical extents and identical constant speed rates.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 1,028,214` Hess June 4, 1912 1,034,154 Smith July 30, 1912 1,689,888 Myers et al Oct. 30, 1928