US3317018A - Manual type action with rolling point contact - Google Patents

Description

y 2,1967 A. R. JOHNSON 3,317,018

MANUAL TYPE ACTION WITH ROLLING POINT CONTACT Filed Oct. 22, 1965 I 2 Sheets-Sheet l Reflepted INVENTOR ARTHUR R. JOHNSON ATTORNEYS May 2, 1967 R. JOHNSON MANUAL TYPE ACTION WITH ROLLING POINT CONTACT 2 Sheets-Sheet 2 Filed Oct. 22, 1965 INVENTOR ARTHUR R. JOHNSON BY v ATTORNEYS United States Patent 3,317,018 MANUAL TYPE ACTION WITH ROLLING POINT CONTACT Arthur R. Johnson, Wethersfield, C0nu., assignor to Royal Typewriter Company, Inc., New York, N.Y., a corporation of Delaware Filed Oct. 22, 1965, Ser. No. 501,305 3 Claims. (Cl. 197-27) This invention relates to a manual type action having a novel motion transmitting system between key lever and type bar; more particularly it relates to a manual type action having a novel motion transmitting system characterized by levers having rollingly engaged surfaces for translating key lever movement into accelerated type bar motion. 7

All efforts of the prior art have been directed to the provision of a type action having elements between key lever and type bar which serve to provide a light key touch and to provide increasingly accelerated motion of the type bar. In such actions the leverage of a key lever, which diminishes as the key lever isdepressed through its full stroke, is greatest at the begining of key depression thus to slowly overcome the inertia of the type bar as seen from the key lever, further key depression aided by momentum increasingly accelerating the type bar. This reduction of type bar inertia as seen from the key lever is however purchased at the expense of time requiring a higher rate of acceleration of the type bar during the terminal portion of key lever depression, Le. a greater and noticeable application of power over the terminal portion of key lever depression.

In accordance with the present invention a motion transmitting system characterized by levers having rollingly engaged camming surfaces comprising an intermediate lever driven by a key lever and driving a type bar sublever in turn is provided whereby the inertia of the system opposing key lever depression at the start is minimized and whereby optimum acceleration is imparted to the type bar. The camming surface contours are such that the work required to accelerate the type bar is distributed over the entire stroke of the key lever. In other words, type bar acceleration may be control-led throughout key depression such that the progressively increasing power requirement or progressive increase in reflected inertia is imperceptible to an operator. A further feature of the invention resides in the fact that the action characterized by double cam surfaces is suited to a segment shift machine and more particularly a segment shift machine wherein a forward pull drives the type bar rearwardly.

An object of the invention is to provide an improved type bar action.

Another object of the invention is in the provision of an improved action which is easily manufactured and assembled with a minimum of time consuming and costly adjustment.

Still another object of the invention is in the provision of an action that, except for the type bar, may comprise a single sub-assembly wherein the elements may be accepted in a single saw cut in a fulcrum bar common to all the actions.

A further object of the invention is in the provision of an action characterized by a very light key touch and optimum type bar acceleration by virtue of double camming levers whose camming surfaces are designed to effect substantially rolling motion during transmission of motion.

A still further object of the invent-ion is to provide a motion transmitting system between key lever and type bar characterized by camming levers that is suited to a segment shift machine.

3,317,018 Patented May 2, 1967 Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings in which like reference numerals designate like parts throughout the figures thereof and wherein:

FIGURE 1 is a sectional elevational view of a center action associated with a key in the highest bank of key levers;

FIGURES 2 and 3 are fragmentary elevational views showing elements'of FIGURE 1 in active positions corresponding to the midflight and printing position of a type bar; and

FIGURE 4 is an exemplary curve showing reflected inertia as viewed from the key lever.

Referring now to the drawings wherein like reference numerals designate like or corresponding elements throughout the several views and wherein a preferred embodiment only is shown there is shown in FIGURE 1 a cast or extruded fulcrum bar generally designated by reference numeral 10 which extends from side to side of the typewriter and is secured to the side frame plates (not shown) of the machine. As viewed in FIGURE 1 the bar has an arcuate substantially semi-cyindrical or cup shaped cross section and is secured on the machine with the lips 11 and 12 facing downwardly; the forwardmost lip 11 higher than the rear lip 12.

The fulcrum bar 10 is transversely sawed to provide a plurality of equally spaced parallel slots or openings 13 each of which is adapted to accommodate elements of a type action in a common vertical plane. The fulcrum bar is also cast or slotted from end to end at three spaced points substantially apart which are adapted to accommodate a fulcrum rod 14 which pivotally supports all of the key levers 15, a fulcrum rod 16 which pivotally supports all of intermediate levers 17, and a fulcrum rod 18 which pivotally supports all of the type bar sub-levers generally designated by reference 19. As viewed'inFIG- URE 1 the intermediate and sub-lever fulcrum bars 16 and 18 respectively are located adjacent the forward and rear lips 11 and 12 of the fulcrum bar, and the key lever fulcrum rod 14 is located in the base portion of the inverted cup shaped fulcrum bar.

As in conventional machines the typewriter keyboard comprises four banks of keys 21; the highest bank of keys having the shortest lever arms 15. In FIGURE 1 key lever 15 is one of the upper bank of key levers. The key levers in each bank are identical and are pivotally mounted at their rearwardmost end on the fulcrum bar 14 and are biased in a preferred design upwardly as by a spring ,22 secured to the upper edge of the key lever and to a bracket 23 secured to the forward side of a rib 24 extending upwardly from the base portion of the fulcrum bar; an upstop 25 also secured to the bracket limiting the clockwise rotation of the key levers.

As shown in FIGURE 1 the lower edge of each key lever from a point close to and forwardly of the fulcrum rod 14 curves downwardly and upwardly to define a predetermined compound curve constituting a cam surface 26. 'The upper edge of the-intermediate lever which extends rearwardly from its fulcrum 16 curves upwardly, downwardly and substantially rearwardly from its fulcrum to define a compound curve constituting a reaction surface 27 which is in point contact with cam surface 26. The radius of curvature of cam surface is such that the starting contact point SCP of the upper bank of keys is as close as possible to the key lever fulcrum 14 as it is this contact point which determines the reduced mass of the type bar as viewed from the key lever at the start of motion and thus the touch characteristics. Further therelative.

contour of these surfaces 26 and 27 is such that the point of contact shifts along the line AA between the centers of fulcrums 14 and 16 and toward fulcrum 16 as the key lever is depressed.

To obtain the same optimum touch characteristics from bank to bank, the starting contact point SCP of banks having longer key levers is displaced further from fulcrum 14 an amount which is proportional to the differences in key lever lengths.

As shown in FIGURE 1 each of the sub-levers 19 is formed with arms 28 and 29 extending upwardly and forwardly respectively from the pivot 18. The end of the upwardly extending arm 28 is connected as by a link 31 to the tail of a type bar 32 which is pivotally mounted for rotation on an arcuate fulcrum rod 33 supported in an arcuate slotted segment 34. When the type bar tails increase in length from center to end bar, all of the sublevers will be driven through substantially the same angle. The segment together with the type bar rest 35 which defines an arc which is flatter than that of the segment is conventionally mounted for case shifting movement along line C-C whereby the pivotal connection between type bar and link swings downwardly through an are from the lower case position shown to an upper case position without disturbing the pivotal connection between sub-lever and link; hence case shifting does not affect the geometric relationship of the elements of an action.

The upper arm of the sub-lever is biased rearwardly as by a spring 36 thus to return the type bar 32 to the headrest position as well as to return the intermediate lever 17, and to return, where spring 22 is not employed, or aid in the return of the key lever 15', to inactive position upon release of a key lever.

The sub-lever fulcrum rod 18 also pivotally supports a conventional universal bar 37 located below legs 38 depending from all of the forwardly extending arms of the sub-levers so as to be driven when any of the sub-levers 19 are rocked counterclockwise.

The lower edge of each intermediate lever curves from its fulcrum 16 downwardly and upwardly to define a predetermined compound curve constituting a camming surface 41. The upper edge of the forwardly extending sublever arm from its fulcrum 18 curves upwardly, downwardly and substantially in a forward direction to define a compound curve constituting a reaction surface 42; the forward portion thereof being in point contact with the arcuate portion of camming surface 41. Inasmuch as the upwardly extending arms 28 of the sub-levers associated with the end bars are the longest and since the end bars must move farther from the arcuate headrest 35 to the platen, the starting contact points SCP' of the cam surfaces of the sub-lever and intermediate lever associated with the end bars are closest to the intermediate lever fulcrum 16 with the contact points associated with actions closer to the center action receding therefrom.

As hereinbefore noted the cam and reaction surfaces 26 and 27 between key lever and intermediate lever are so contoured that the point of contact moves along line A--A between the key lever and intermediate lever fulcrum centers. Similarly the contours of the cam and reaction surfaces 41 and 42 between intermediate lever 17 and sub-lever arm 29 are such that the point of contact moves along line BB' drawn between intermediate and sub-lever fulcrum centers. Thus substantially pure rolling engagement between these engaging surfaces is attained, eliminating all frictional resistance as would otherwise result from sliding engagement. In view of the above geometry, i.e. the progressively decreasing moment arm of the key lever 15 and corresponding increase in the angular velocity of the intermediate lever 17 as the point of contact between surfaces 26 and 27 shifts along line AA', and the progressively increasing moment arm of the intermediate lever 17 and corresponding progressive angular displacement of the sub-lever 19 as the point of contact between surfaces 41 and 42 shifts 4 along line BB', there results a very sensitive and light key touch and optimum type bar acceleration; the cam and reaction surfaces being so predeterminedly contoured that the work required to effect acceleration is distributed throughout the full key lever stroke in a manner as illustrated in FIGURE 4.

As noted hereinbefore it is essential to an action with optimum touch characteristic i.e. low reflected type bar inertia at the start and high reflected type bar inertia at the end of motion as illustrated in FIGURE 4, that the starting contact points of upper bank actions must be as close to the key and intermediate lever fulcrums as possible.

As viewed in FIGURE 3 the final contact points PCP and PCP between key and intermediate levers and between intermediate and sub-levers respectively are close to the intermediate lever fulcrum 16 and the sub-lever fulcrum 18. Thus a toggle condition which is required in a conventional lever and link action is avoided and substantially all of the energy is transferred to the type bar to produce useful print work.

In view of this essential requirement it is evident that any change in orientation of the various levers will severely affect the starting contact points. Such changes in orientation will arise as a result of normal manufacturing tolerances which produce play in the action train. In accordance with the invention the reaction surfaces 27 and 41 are designed i.e. the angles from fulcrums to all points on the reaction surfaces are rotated a small increment such that the starting contact points SCP and SCP are above the line of centers, AA', BB', a distance which will allow for normal manufacturing tolerances thus to maintain the starting contact points constant. Although this correction will give rise to initial sliding motion over a distance d at the beginning of key lever depression as illustrated in FIGURE 4, it is not objectionable because the contact points are close to the fulcrums 14 and 16 and the finger on the key has a very large mechanical advantage; also the amount of sliding is infinitesimal since the displacement of the contact point above the line between fulcrum centers is very small. Accordingly the engagement of the cam and reaction surfaces is substantially rolling motion along the line of centers A-A' and B-B'.

In operation then depression of a key lever 15 results in clockwise movement of the intermediate lever 17 by virtue of the rolling contact therebetween surfaces 26 and 27 starting from point SCP, and counterclockwise movement of sub-lever 19 by virtue of rolling contact be tween surfaces 41 and 42 starting at point SCP'. Thus maximum mechanical advantage and a low reflected type bar inertia viewed from the key lever is attained at the beginning of the cycle and a high rate of acceleration is subsequently attained in a progressivee manner throughout the remainder of the stroke as the contact points trace line A-A' and B-B' from the FIGURE 1 to the FIGURE 3 position.

It should be understood that the foregoing disclosure relates to only a preferred embodiment of the invention and that it is intended to cover all changes and modifications of the example of the invention herein chosen for the purposes of the disclosure which do not constitute departures from the spirit and scope of the invention.

The invention claimed is:

1. A type action for a manual typewriter having a type bar supporting segment,

a type bar pivotally mounted on said segment,

a pivotally mounted sublever having a reaction surface,

a link connecting said sublever and type bar whereby said type bar will be driven when said sublever is rotated about its pivot,

a pivotally mounted key lever having a camming surface,

and a pivotally mounted intermediate lever having a reaction and a camming surface in point contact with and contoured relative to said key lever carnming surface and said sublever reaction surface respectively such that upon key lever depression said key lever camming surface acts by rolling contact with said intermediate lever reaction surface to rotate said intermediate lever about its pivot at a progressively increasing angular velocity and said intermediate lever camming surface simultaneously acts by rolling contact with said sublever reaction surface to rotate said sublever about its pivot at a progressively increasing angular velocity.

2. An action as recited in claim 1 wherein the starting and final contact points between cam and reaction surfaces of said key and intermediate levers are adjacent the pivot of said key lever and adjacent the pivot of said intermediate lever respectively, and the starting and final contact points between reaction and cam surfaces of said intermediate and sub-levers are adjacent the pivot of said intermeediate lever and adjacent the pivot of said sublever respectively.

3. An action as recited in claim 1 wherein said segment is shiftable between upper and lower case positions, wherein said sublever is pivoted forwardly by said intermediate lever to drive the type bar upwardly and rearwardly, and wherein said link between sublever and type 6 bar extends substantially horizontally whereby shifting of said segment does not disturb the pivotal connection of sublever and link and the contact relationship between said cam and reaction surfaces.

References Cited by the Examiner UNITED STATES PATENTS 657,438 9/ 1900 Mosher 197-28 970,076 9/ 1910 Merritt 19727 1,011,924 12/1911 Daugherty 19728 1,021,513 3/1912 Felbel 19727 1,025,752 5/1912 Latta 197-28 1,269,200 6/ 1918 Mosher 197-28 1,619,391 3/1927 Woodruif 19728 1,710,751 4/ 1929 Von Reppert 19727 1,841,112 1/ 1932 Garbell 19727 2,002,395 5 1935 Hess 19727 2,008,384 7/1935 Benzing 19727 2,142,375 1/1939 Reppert 19727 3,164,085 1/1965 Hawkins 10193 ROBERT E. PULFREY, Primary Examiner.

E. S. BURR, Assistant Examiner.

Claims (1)

1. A TYPE ACTION FOR A MANUAL TYPEWRITER HAVING A TYPE BAR SUPPORTING SEGMENT, A TYPE BAR PIVOTALLY MOUNTED ON SAID SEGMENT, A PIVOTALLY MOUNTED SUBLEVER HAVING A REACTION SURFACE, A LINK CONNECTING SAID SUBLEVER AND TYPE BAR WHEREBY SAID TYPE BAR WILL BE DRIVEN WHEN SAID SUBLEVER IS ROTATED ABOUT ITS PIVOT, A PIVOTALLY MOUNTED KEY LEVER HAVING A CAMMING SURFACE, AND A PIVOTALLY MOUNTED INTERMEDIATE LEVER HAVING A REACTION AND A CAMMING SURFACE IN POINT CONTACT WITH AND CONTOURED RELATIVE TO SAID KEY LEVER CAMMING SURFACE AND SAID SUBLEVER REACTION SURFACE RESPECTIVELY SUCH THAT UPON KEY LEVER DEPRESSION SAID KEY LEVER CAMMING SURFACE ACTS BY ROLLING CONTACT WITH SAID INTERMEDIATE LEVER REACTION SURFACE TO ROTATE SAID INTERMEDIATE LEVER ABOUT ITS PIVOT AT A PROGRESSIVELY INCREASING ANGULAR VELOCITY AND SAID INTERMEDIATE LEVER CAMMING SURFACE SIMULTANEOUSLY ACTS BY ROLLING CONTACT WITH SAID SUBLEVER REACTION SURFACE TO ROTATE SAID SUBLEVER ABOUT ITS PIVOT AT A PROGRESSIVELY INCREASING ANGULAR VELOCITY.

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