US1071976A - Shift mechanism for type-writers. - Google Patents

Description

A. W. WEEDEN.

SHIFT MECHANISM FOR TYPE WRITERS.

APPLICATION FILED MAY 20, 1912.

3 SHEETS-SHEET 1.

Patented Sept. 2, 1913.

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A. W. WEBDBN.

SHIFT MECHANISM FOR TYPE WRITERS.

APPLIOATION FILED MAY 20, 1912. 1,071,976. Patented Sept. 2, 1913.

3 SHEETS-SHEET 8.

wa'znesaesu A. W. WBEDEN.

SHIFT MECHANISM FOR TYPE WRITERS.

APPLICATION FILED M'AY 20, 1912. 1,071,976. Patented Sept. 2, 1913.

3 SHEETS-SHEET 3.

Inventor.- W W 77% y Wm Wit/726556 s ARTHUR W. WEEDEN, 0F SOMERVILL'E, MASSACHUSETTS.

SHIFT MECHANISM FOR TYPE-WRITERS.

emme.

Specification of Letters Patent. Patent ml Soptufl, 1913.

Application filed May 20, 1912. Serial No. 698,384.

1 b all whom 5t may concern Be it known that I, .An'rnnn \V. i vmcnnx, a citizen of the United States, residing at Somerville, in the county of liiiddlescx, State of Massachusetts, have invented a cor tain new and useful Improvement in Shift Mecl'ianism for Type-\Vriters, of which the following is a specification, referen e being had therein to the accompanying drawings My invention relates to mechanism employed in the construction of typewriting machines or the like, for shifting the position oi. the platen, or of the carriage carrying said platen, relatively to a type bar on which is carried a plurality of characters, so as to locate said platen in a proper printing position with respect to the character which it is desired to bring into printing action.

My invention more particularly relates to shitting mechanisms of a kind in which the change in position of the platen is accomplished through the depression of the key end of a key bar producing a swinging movement in a curved path of the free end of said key bar about a fixed pivot, which swinging movement is adapted to et'l'ect, through approximate mechanisms engaged by said free end, the desired shift in the position of the platen.

One object of the invention is to construct a mechanism having the capacity oli cttecting the shift of the platen in a noiseless manner.

Another object is to provide a means of supporting and pivoting the key bar so as to permit a (liSPlttCOtTitJit, with respect to its normal, of the cln'vcd path in which the il rec end of the key bar moves, when the key is depressed, which disp acement is rendered operative, through the connecting mechanisms, to effect a correimonding variation in the position to which the platen is shifted; the construction by which the displacement ot the path of movement of the free end is secured further being one which permits such displacen'lent without altering the level at which the key end of the bar is maintained on the key boa rd.

My invention therefore resides in a corn struction for shifting a platen with respect to the type bar, which embodies a means of adjustment permitting a variation in the position to which the platen is shifted without disturbing the normal or initial position of the same, such adiusting means being so constructed that the chan es in the position of the same by which the desired variation in the platen shift is secured is without appreciable etl cct upon the position of the key on the key board; the mechanisms employed further being of such nature as to have the capacity of performing their functions in a quiet and noiseless manner.

\Vhile my invention is capable of: embodiment in many varying forms ol shifting mechanisms it lends itself especially to that type of mechanism in which the free end of the key lever engages a cam-groove or cam-surface and in its swinging movement causes the part carrying such cam surface to swing or rotate with respect: to its support. My invention also is oil CSPPClfIl admitabilitv in mechanisms by which a double shift of the platen may he provided. I have, therefore, in the 'tollowing specification more particularly shown and described my invention as embodied in a double shift mechanism for the platens ot tiypcwriting machines, or the like. in which the platen derives its shifting movement from the change in position of a cam piece or member etiectcd through the swinging movement oil a cam-engaging member carried at the "free end of the key bar or key lever, and engaging a cam-surface or cam-groove carried by said cam-piece.

Referring to the drawings which aceon'ipany this specification and form a part oi? this application, F igurclshows in elevation aplatcn shitting mechanism of the doubleshift type, embodying my invention. Fig. 2 is a plan View of the portions of the mechanism shown in Fig. 1, which particularly relate to my invention, certain parts oil said mechanisms being shown in section. Fig. 3 is a side elevation of the bracket, on which are mounted the supports on which the key lever is carried. Fig. 4 is an elevation illustrating a modification in the manner oi? supporting the key lever. Fig. illustrates a Further modification in the manner of supporting the key lever, l ig. 6 being a sec tion 01 the same on the plane zr.r, of Fig. 5. Fig. 7 is a side elevation, partly in section, shmving another type of mechanism embodying my invention. Fig. 8 shows a )lan view of theinechanism shown in elevation in Fig. 7, certain portions of the same being shown in section to more clearly illustrate the construction thereof; Fig. 9 being an end elevation of the same. 10 is an elevation showing the construction of a part of the adjusting mechanism. Figs.

11 and 12 are respectively an elevation and a plan view, shown partly in section, of a further modification of my invention, Fig. 13 being an end view of the platen shifting lever and cams actuating the same. Figs. 1a and 15 present a modification of certain portions of the mechanism shown in Figs. 11, 12 and 13.

Referring to the drawings 1 represents a part of the frame or bed of the typewriting machine, on which are carried the frame journals 2, 2, having rotatably mounted therein a shaft 3. On said shaft 3 is carried a lever 1 which is securely fixed thereon as by means of a pin 4. The free end of said lever l engages the lower end of a link 5 leading to and secured at its upper end, as by a pin 12 to a vertically movable rail 6 on which the carriage 7, carrying the platen 8, travels; said carriage being preferbly supported upon said rail 6 by a ballbearing or other appropriate construction. in the normal position of the platen the same is positioned in proper printing relation with respect to a character 10 carried on a type bar 11, the position of the platen with respect to said character being susceptible to adjustment if desired by means of a. slot 12, in which the pivot 12, through which the link 5 engages the rail 6 may be adjustably positioned, or in other appropriate manner. The type bar 11 carries besides the character 10, the characters 13 and 1 1-. The mechanism hereinafter de scribed is designed to raise the platen either to the dotted position 8, in which it is in proper printing position with respect to the character 13, or to lower the same into the dotted position 8 in which the platen is in proper printing position with respect to the character 14. The mechanism preferably adopted to effect the shift in position to the platen either to the posit- ion 8 or 8 includes, in the embodiment now being described, cam piece 15 which is rigidly secured to the shaft 3 as by a pin 16. The upper portion of said cam is provided with two cam grooves 17 and 18, in which grooves the rollers 19 and 20, respectively, are designed to travel. Said rollers 19 and 20 are respectively carried at the free ends of the key levers, 21 and 22, which are provided with suitable manipulating keys, 23 and 24, located in the key board of the machine. The rollers 19 and 20 are preferably revolubly mounted, as by pins 19 and 20, secured in forked ends 25 and 26 formed on said keys, said forked ends of said keys be- Fig.

ing so formed that either of the same may swin upwardly without interference from the other. For this purpose preferably the forked end 25 carrying the roller 20 and straddling the edge 15 of the cam isoffset, as shown, permitting the upward movement of the same without interference from the forked end 26 of the lever 21, carrying the roller 19 and straddling the forward edge 15 of said cam; said forked end 26 being in a similar manner free to swing upwardly without interference from the end 25. In Fig. 1 those parts of the forked ends 25 and 26 nearest the observer are broken away, to show more clearly the relations of the lower ends of the grooves 17 and 18, and the rollers 19 and 20 lying therein in their normal position.

The key levers 21 and 22 are independently supported respectively on the brackets 27 and 28, through the combined action of the supporting pins 29 and 30 and of the adjustable pivot rolls 31 and 32. For the sake of clearness the supporting bracket 27 is not shown in Fig. 1, only the pin 29 and the pivot roll 31 being there shown in section. The pin 29 is preferably formed integral with said bracket 27, although the same may be formed and supported thereon with a capacity for change in location or adjustment forward provided if desired, in any approved manner. The bracket 28 is secured to the frame 1, as by cap bolts 28 and 28 engaging said bracket 28 and passing through openings in the said frame, which are preferably slotted to permit an adjustmentin the position of the bracket on the frame, if so desired.

The pivot rolls 31 and 32 are carried upon the pins 33 and 34, pin 34: being mounted upon a block 35 adapted to slide within a curved slot 36 formed in the supporting bracket 28, in which slot it may be fixedly secured if desired through a nut 37 engaging a threaded extension 38 of the same, and clamping the block 35 within said slot. Pin 33 is similarly mounted on a block 35 located in a slot formed in bracket 27, although not shown in Fig. 1. The pivot roll 31 is preferably eccentrically mounted upon the pin 33 and is adapted to be fixedly secured in a desired position of rotation upon said pin by means of the nut 39. A similar construction is employed to secure the pivot roll 32 on the pin 34.

The key lever 21 is supported upon the supporting pin 29 and the adjustable pivot roll 31, and the key lever 22 upon the pin 30 and pivot roll 32 in the following manner: Said pin 30 is adapted to slidingly fit within a longitudinal slot 10 provided in the key lever Adjacent said slot and a little to one side of the same, at the right as shown in Fig. 1, there is formed, in a central enlargement ll of said key lever 22,

a curved slot 42 oi a width adapted to permit the pivot roll 3? to freely slide throughout its entire length. The curvature o't' said slot 12 corresponds with that of the arc of a circle described about the center oi the roller 20 when the same is at the normal position adjacent the lower end of the camgroove .18 as shown in Fig. 1. In like mannor a curved slot L3 is formed in the key lever 21 having a curvatin'e coincident with that oi? the are of a circle described about the center of the roller 19 carried at the end of the key lever 21. The curvature of the slot 36 -i'ormed in the supporting hracket 28, and in which the block carrying the pivot roll 32 slides, is also concentric with that oi the curved slot 41-2 of the key lever 22. Similarly the curvature of the slot formed in the hracket 27 is concentric with that of the key lever slot 43. As in the case of lever 22, the pin 29 slid'ingl'y [its within a longitudinally elongated slot 14i. From this construction it is apparent that the pivot rolls 2:31 and 32 may he located either near the center of the key lever slots 1O and 44, as shown in Fig. 1, or they may he raised or lowered, within the range of movement permitted, without disturbing the position of the rollers 19 and 20 carried at the ends of said levers, by reason of the fact that said rollers are centrally located with respect to the circular arcs defining the slots in which the pivot rolls 31 and 32 move.

From the method of supporting the key levers hereinheitore described it is evident that the pins 29 and 30 will operate to position the keys 23 and 2 1 always at the desired elevation in the key heard. It is also evident that pivot rolls 31 and 32 will serve to control the longitudinal position of the key levers 21 and and oi the rollers 19 and 20 carried at the free ends of the same. it is :iurther apparent that the engagement of said lcngiiiulinally immovable rollers 11) and 20, each against the side of the groove in which it is located, will prevent the cam piece from swinging in either direction, and will hold the cam piece rig dly fixed in its normal position, in which position the platen will he located in its proper printing relation with respect to the character 10. It will also he seen that the (lOIHPSSlOH of the key 253 oi the levcr 21 will cause the tree end oi? the lover to move upwardly, the swinging oi the lover, at the same time causing the slot i to move downwardly tor a, slight amount with reference to the pivot roll 31, Moreover the free end oi said lover will swing ahout the center of which the exact location more or less dependent upon the relative position of the pin 29, and the pivot oller iii. although such location is more 0S1)0(.1nlly controlled by the pos tion (it the pivot roll 31. The swinging of the lever 1 about the pivot roll 31 will in turn cause a slight longitudinal movement 01' pin 29 in the slot 44;; which movement, although oi? almost unapprcciahle amount in the normal position oi? the roll 31, as shown in Fig. 1, will materially increase as the location of the said pivot roll is changed so that it occopies the dotted positions indicated at 31" and 31." and locatcd respectively near the upper and lower ends oi? the slot 13. The swinging movement oi the tree end of the key lever 21 is arranged to produce a lowering of the platen into the position 8', and that of the end oi? key lever 22 to produce an elevation oi the platen into the position oi S in the following manner: The cam groove 17 is oii such term that as the roller 19 swings ahoui its support, moving in the curved path (1, indicated hy the dotted line, which path (I, may he assumed to suhstaniially coincide with an arc centered at the normal position oi the pivot roll 2,1, such movement will cause a rotation oi? the cam piece 15 in an anti-clockwise manner. The said groove is further so designed that at the limit oi? the swinging movement of the roller 19 a rotation oi the cam groove will have been produced suil'icicnt to cause a downward movement of the lever -.iof such extent that the platen will he lowered into position 8" opposite the character 14-. To permit this rotation oi the cam piece with respect to the roller 20, which during the swinging movement oi. the key lcver 21 and roller 19 will remain stationary, the lower ends oi? the grooves 17 and 18 are interconnected. as shown, hy the connecting groove 187. Such groove 18? has a length great enough to permit a rotation oi? the cam piece 15 suilicient to produce the desired lowering oi the platen S, hci ore the position at the lower end oi the slot 17, previously vacated hy the roller 19 as it is swung upwardly, coincides in position with that of roller 20; the fitil'h' 23 at the end oi? the lever 22, 'iurther hcing oi suiiicicni depth to permit such rotation of the cam piece without hringing the edge 1-3 oi" the cam piece. into interiierence with the same. In a similar mannor the cam groove '19 is so designed that: the upward swinging movcnmnt oi the roller 20 through its range oi movement will prodncc a clocliwiso rotation oi the cam piece 15. which will he transmitted through the lover i and move the platen S into position 8, the intorcoimccting groove 197 at the same time permitting the rotation of the cam piece without interference irom the roller 19.

The Form oi the cam grooves necessary to eil'ect the results just descrihcd can he rcadilv designed hy any competent dra'itsman. having in mind the desirahility oi oii'cciing the rotation oi the cam to the desired amount hy means of the travel oi the roller with a gradual movement oi the cam sur- V ersed by the roller.

face at the start and finish of the path trav- A cam piece having cam grooves of the nature shown in Fig. 1 presents one form which such cam grooves may take. Preferably there is a dwell, or portion of the groove which is so designed that the swinging movement of the roller is without effect to move the cam, at the beginning 17"-, 18 and at the finish 17*, 18 of each of the cam grooves, such dwell at the beginning of such grooves carrying the lower ends of said grooves somewhat below the rollers traveling therein, so that the lower edge of the connecting groove 187 is somewhat below the rollers 19 and 20. The purpose of such dwell is to permit the rotation of the cam to be completed before the roller impinges against the extreme end of the cam groove. in consequence, stops 45 and 46, secured respectively to frame at 1 and at 1*, with a capacity for adjustment in height, either by screw 47, or through shims 48, and carrying pads 49 and 50, adapted to absorb the impact of the key lever 21, thereagainst without noise or shock, may be employed to limit the swinging range of the roller 19 so that its travel in the groove may be stopped without impact of said roller against either upper or lower end of the groove. Thus from the construction just described there results a platen shifting mechanism which efiects a change of posi tion of the platen in a quick and easy manner, and without accompanying noise or shock incident to operation.

\Vhen it is desired to alter the position into which the platen is raised or lowered by the action of the shifting mechanism, the desired result can by accomplished by a change in the position of the pivot roll about which the proper key lever swings. Thus assuming it to be desired to increase the lowering of the platen, the pivot roller 31 may be raised by loosening the nut 37 car ried on a threaded extension 38 of the block 35*, and moving the block 35 upwardly in the curved slot formed in the bracket 27, wherein it may be again clamped by retightening said nut 37*, so as to locate said pivot roller in a new position, for example that indicated at 31". This change in position of the pivot roll 31 will not disturb the normal position of the roller 19, as shown in Fig. 1, since by assumption said roller 19 is at the center of the are upon which said curved slot is defined and through which said pivot roll 31 has been moved. The change will however cause the path in which the roller 19 is carried, as the free end of the lever swings upwardly, to follow substantially along the path Z) inclining at its upper end to the left of the original path (4. Thus the rotative movement of the cam piece 15 will be greater for a given angular movement of the roller 19 than originally, and the position into which the platen will be shifted will consequently be somewhat lowered. Similarly a relocation of the pivot roll 31 in the position 31 near the lower end of the curved slot 43 will cause the free end of the lever and the roller 19 to follow substantially along thepath a inclining to the right of the original path a, thus lessening the amount of rotative movement of the cam piece and causing the position into which the platen will be shifted to be slightly higher than before.

Figs. 4, 5 and 6 are designed to illustrate modifications in the manner of supporting the key levers, the supporting pin 30 and slot 40 of the construction shown in Figs.

1 and 2, being replaced, in Fig. 4, by a swinging link 51 pivoted to the lever at 52 and to the bracket 53 at 54, while in Figs. 5 and 6 the lever 55 slides in a yoke 56 which is adapted to swivel with respect to bracket 58 upon a cylindrical projection 57.

Figs. 7, S, 9 and 10 illustrate another embodiment of my invention, in which the single cam piece 15, of Figs. 1 and 2, having two cam grooves, is replaced by two independent cam pieces, each carrying a single groove, and in which the method of effecting an adjustment by varying the path in which the free end of the key lever is compelled to move is carried into effect by mechanism diflering somewhat in details of construction from that previously described. Referring to said Fig. 7, 61 and 62 represent key levers operated through the keys 68 and 64. The end of key lever 61 is forked as shown more clearly in Fig. 8, and carries at its end the roller 65; lever 62 being similarly forked at its end and carrying a roller 66. The roller 65 engages and slides within a cam groove 67 formed in a cam piece 68, roller 66 in a similar manner engaging and sliding within the cam groove 69 carried in a cam piece 70. Both said cam pieces are fixedly mounted as through pins 71 upon a shaft 72 which is adapted to rotate in journals 73 carried by the frame 74 of the typewriter in any approved manner. Said shaft also carries, preferably pinned thereon, the lever 75, which corresponds to the lever 4 of Fig. 1, and may be connected with the platen by means similar to that shown in Fig. 1. Said means and said platen, however, are not shown in said Fig. 7. The cam levers 61 and 62 are respectively supported on brackets 7 6 and 7 7 which are carried on the frame 74, and. are secured thereto preferably by cap bolts 78 engaging the bases 76 and 77 of said brackets and having capacity for longitudinal movement with respect to the frame by reason of slots 79 provided in the. base or frame for that purpose. The said levers 61 and 62 are respectively supported on the sides of the brackets 76 and 77 by means of pins 80 and 81 passed through slots in the .key lever, of which slots only that formed in lever 62 is shown, as at 8'2. Said pins 80 and 81 support the key levers and position the keys (33 and (3-1 at the desired elevation on the key board. For controlling the longitudinal position of the key lever (32 a link 83 is provided, said link being pivoted at one end through a pin 8 1; with said key lever 62. At its other end the link 83 is pivoted, as by bolt 85, with a sliding stud 86 carried on said bracket 77 with a capacity :lior being secured therein in various positions. The 1nret'erred construction of said sliding stud and the manner of adjusting the position of the same upon the bracket 77 are more clearly shown in Fig. 8, in which said stud S6 is shown in section on the plane Q 1 in Fig. 7. Said bracket 7 7 is curved at its upper part and is provided with a slot 87, shown more clearly in Fig. 10. The faces of said slotted portion of the bracket are pretferably beveled as shown in section in Fig. 8. Against one of such faces is located the trout portion S6 of the stud 8G and against the back :tace is located the back portion 86" of the stud, the bearing surfaces of each such portions being preferably titted to the beveled faces of the bracket adjacent the slot. By a screw 86 the front and the back portions of the stud may be drawn together, clai'nping the stud 86 as a whole upon the beveled faces of the slotted portion of the bracket 77 in the desired position. Said slotted portion of the bracket 77 is finished so that its faces coincide with an arc circumscribed about the pivot S-t at a center. Thus the movement of the stud 86 upon the bracket 77 will not cause any longitudinal movement of the lever (32 which will disturb the position of the roller (36 carried upon the free end of said key lever. In a similar manner a stud 88 is slidingly mounted upon a curved and slotted portion of the bracket 76, and is connected, as by a link 89, piv- .cted to the stud St) at 90 and to the key lever or at 91, is adapted to control the longitudinal position of the said lever 61. The faces of that slotted portion of said bracket To on which said stud 88 is adapted to slide is in the form o't an are described about 91 as the center so that a change of position of said stud will not disturb position of the roller 65. From the method of supporting the key levers hereinbetore (lcscribed it will be understood that the pins 80 and 81 will locate the keys (3?) and (3% always at the desired elevation in the key board, and furthcr that as said keys are depressed, the "tree ends oi? the key levers and the rollers carriedv theretm will swing about centers of which the exact locations are dependent upon the relative positions of the pins 80 or 81 with respect to the stud pivots 90 or 8:); said centers however being more particularly determined, as heretofore mentioned in connection with Fig. l by the position of the stud pivots 85 and 90. Thus as the key (53 is depressed the roller (35 at the end of the lever (51. will swing upwardly in a path which substantially that oil an are described about the stud pivot 90 as a center. in such movement it will traverse the cam groove (37 in the cam piece (38, such groove being designed in a manner similar to that hereinbetore described in connection with the groove 17 oi? Fig. 1, so that when the roller (55 reaches its upward limit of travel of movement in the cam groove 7 will have caused the cam piece (58 to rotate in an anticlockwise direction by an amount adapted to cause the lever 75 connected with said :am piece through the shaft 753 to move (.hmunvardly sutl'icient to cause a lowering of the platen to the required position. In a similar manner the depression of the key (it will cause the roller (36 to swing upwardly in a path which is 'n'ineipally controlled by the position of the pivot 85, in which upward movement it is adapted to slide in the groove (39 of the cam piece and to rotate said cam piece 70 in a clockwise direction by an amount sullicient to cause the upward movement oi? the lever 75, and the elevation of the platen to the desired position. At the bottom of each of said grooves (57 and (39 are provided the lateral extensions (37 and 69 which permit the rotation of the cam piece in the cam groove of which the roller carried by the idle key lever is located, with respect to such roller, when the other key lever is actuated. It will Further be seen that as the studs 88 and so are moved toward the upper end oi the slotted portions of the brackets on which they are carried the ell'ect will be to raise the points about which the rollers (35 and (it) swing, thus inclining the paths in which said rollers travel toward the left with respect to the normal paths tollowed by said rollers when the said studs are located near the center of said slotted portions. in a similar manner the lowering o'l. said studs will cause paths to incline toward the right as compared with said normal paths. Thus the change of location of tho pivots 85 and 9t) through the positioning ol the studs 86 and 8S allords a means for adjustment in the position to which the platen is raised or lowered in a manner analogous to that as hereinbe'lorc described in conncc tion with Fig. 1.

in Figs. '11, i2 and. 13, is shown another embodiment of my invention ol which the general construction is similar to that shown in l igs. 7, S, S) and it), with the difi'crcncc however, that there is a mechanical inversion with relation to the cam-grooves and the cam-rollers engaging the same; the canrgrooves being in Figs. ll, 12 and 1;), being carried upon the ends of the key levers and being adapted to slidingly engage with the rollers by which the platen shifting lever is actuated. Referring to said Figs. 11, 12 and 18, 92 and 93 represent key levers operated through keys 9 1 and 95, which are supported respectively on the brackets 96 and 96 in a manner preferably as shown and described in connection with Fig. 7. The platen shifting mechanism may be connected with the platen by means of mechanism preferably similar in construction with that shown in Fig. 1, and receiving its shifting movement from the lever 97 which corresponds to lever a, of Fig. 1. The said platen and means connecting the same with said lever 97' are omitted in Fig. 11, as an operative arrangement of the same is fully shown in Fig. 1. Said lever 97 comprises a horizontal arm forming prefer ably an integral part of a bell crank lever, pivoted upon shaft 98 rotatably supported in the journals 99, and having a vertical extension 97, carrying atits upper portion a cylindrical member 97 projecting on either side from said vertical arm 97 as shown. At the end of said cylindrical mem- 97 is carried rollers 100 and 101, preferably rotatably mounted thereon as by screws or studs 102 and 103. Preferably the head of each screw is somewhat larger than the diameter of the roller mounted thereon. Furthermore washers 104; and 105 are located between the cam roller and the end of the roller carrying support 97 For the sake of clearness however, the said washer 105 and the head of the screw 102 are omitted in the elevation shown in Fig. 11. At the free end of key lever 92 is provided preferably as an integral part of the same, as shown, the cam piece 106, in which cam piece is formed a cam groove 107 within which the roller 100 is adapted to slide.

In a similar manner the free end of key lever 93 is provided with the cam piece 108 having the cam groove 109 formed therein, and slidingly engaging the roller 101. The cam groove 107 is so formed that as the key 9 1 is depressed, tilting the key lever 92 and carrying its free end with the cam piece 106 located thereon upwardly, such upward movement of the cam groove 107, with respect to roller 100 will cause said roller to move toward the right, as shown in Fig. 1, and so produce a clockwise rotation of the vertical arm 97" and of the horizontal lever 97, in consequence of which the platen will be elevated. In a similar manner the depression of the key 95 will cause an upward movement of the cam groove 109 carried in the cam piece 108 at the free end of said key lever 93, which will cause a left ward motion of the roller 101 and an anticlockwise rotation of the arm 97 and the lever 97, resulting in a lowering of the platen. As hereinbefore explained in the embodiment of my invention, the cam groove 107 is provided with a lateral elongation 107 situated at its upper end which permits the roller 100 to move leftward with respect to said cam piece 106 as the lever arm 97, carrying the said roller, is rotated in anti-clockwise direction in consequence of the upward movement of the cam piece 108. In a similar manner the groove 109 is provided with a lateral elongation .109 at its upper end which will permit the movement toward the ri ht of the roller 101 with respect to cam piece 108 when the key 92 is actuated and key 93 is in its normal position, both such lateral extensions being wider than the roller for the reasons explained in a previous portion of this specification. The washers 10a and 105, in coiiperation with the heads of the screws 102 and 108, prevent the cam pieces from lateral displacement with respect to the rollers sliding within the cam grooves formed in such cam pieces. The key lever 98 is supported upon the bracket 96* through the screw 110 fitting slidingly within a laterally elongated slot 111. A similar construction is adopted in supporting key ever 92 upon the bracket 96. The key lever 92 is secured against lateral displace ment by a link 1'12 pivoted at one end to the key lever 92 at 113, and engaging at its other end through a bolt 114' with a stud 115 slidable up and down upon the bracket 96 and adapted to be clamped in the desired position thereon through the screw 116, all being constructed and arranged as hereinbefore described in connection with Figs.

7, 8, 9, and 10. By loosening the screw 116 l e height at which sald stud'1l5 may 1 be s-cured upon the bracket 96 may be varied, such a change 1n position operating to change the location of the center about.

which said lever swings, in manner hereinbefore explalned in connection with Figs.

7, 8, 9, and 10. Thus a means is provided.

by wiich the range of movement of the rollers carried upon the arm 97 a and through which the lever 97 is caused'to swing, may be more or less varied, thus providing a means for the adjustment of the position to which the platen is shifted. Padded stops 117 and 118 are provided to limit the swing of lever 92 and to stop such swing before impact of the roller against the ends of the slot 107 can occur. Appropriate means, as for example the spring 119, is provided to normally retain the lever 92 at its lower limit of rotation, at the same time permitting the same to swing upwardly when desired. Similar means not shown in Fig. 11 is employed to define the limits of movement of the lever 93 and to yieldingly retain the same in its normally lowered position.

Figs. 14!. and 15 show a modification in the manner of supporting the rollers engaged by the cam pieces 106 and 108, which modification is more especially adapted to typewriting machines in which the platen elevating mechanism is ope 'ated through a shaft which extends transversely across the machine, instead of upon a short sha'lt as shown at 98 in Fig. 13. In such case it may become necessary to pr wide an ollset in the shaft in order to prevent interference between said shaft and the :am pieces. Thus in llig. 1'-l-, shaft 120 may he carried in bearings 121 and 122 suitably mounted on the trame ot the machine in usual manner, on said shat't being secured a lever 12 i, corresponding in function to the lever 97 ot l ig. ll, tor actuating the platen. tin said shalt are fixedly mounted two vertical arms 152i, and 125, on the ends of which is carried a bar 126 lying substantially in alinemcnt with the shaft 120. On such bar are rotatahly mounted rollers 197 and 128, which rollers may be retained on said bar 126 with out lateral (,llS]')liLC(!1TlClll1 by any approved means. On either side of each of said rollers are pre'te'ably provided washers 199. Said rollers 127 and 'lQfv tit and slide with in cam grooves provided. in the arm pieces 106 and 108, which may be assumed to be similar to those shown in Fig. It. To avoid interference with the shaft 120 by the lower ends of said cam pieces when the same are in their normal lowered positions as shown in Fig. 1 1', the shaft 190 is otlset at 120 by an amount sntticient to afford the necessary clearanc in other respects the mechanism and mode of operation is similar to that shown in Figs. 11, 12 and 13.

llaving described my invention I claim 1. In a typewriter, a vertically movable carriage carrying a platen normally located in a mid position, a movable lever arm, means connecting the said arm with said carriage tor shitting the same to a higher or lower position in response to a predetermined movement of said lever arm, a. pair of am pieces having tam grooves formed therein, a pair ot lcey levers carrying rollers and eiigaging said -am groove id rollers being each normally positioned ad'iacent one end ot the cam groove engaged thereby and being adapted to swing in a tixed path about a centr: 1 point as its key lever is operated and to traverse said groove, each ot said cam grooves being so 'lormed in its cam piece with relation to the path oi. the roller engaging the same that the traverse ot one roller in its cam groove will *anse the cam piece carrying the same to rotate in one direction and the traverse ot the other roll-er in its groove will cause the cam piece 'arrying said groove to rotate in the other di-- reetion, connections whereby the rotative movement of the cam pieces is transmittwl to said lever arm, and means tor independently changing the paths of said rollers.

2. n], a typewriter, a vertically mo able carriage carrying a platen normally located in a mid position, a movable lever arm, means c nnecting the said arm with said carriage tor shitting the same to a higher or lower position in response to a predetermined movement ot said love arm, a pair of cam pieces having cam grooves formed therein, a pair of key levers carrying rollers and engaging said cam grooves, said rollers being each normally positioned adjacent one end ol? the cam groove engaged thereby and being adapted to swing in a lixed path about a central point as its ltev lever is ope 'aled and to traverse said groove, Each o'l said cam grooves being so formed in its :am pieze with relation to the path ot' the roller engaging the same that the traverse of one roller in its ram groove will cause the cam piece rarrying the same to rotate in one direction and the traverse ot the other roller in its groove will cause the tam piece -arrying said groove to rotate in the other direction, connections whereby the rotative movement ol? the cam pieces transmitted to said love arm, and means for independently changing the point about which each roller swings.

ii. in a typewriter, a vertically mo able carriage carrying a platen normally lo :ated in a mid position, av movable lever arm, means connecting the said arm with said carriage :lor shifting the same to a higher or lower position in response to a predetermined movement o'l said lever arm, a pair of cam pieces having cam grooves termed lhereima pair of key levers -ar 'ying rollers engaging said cam grooves-,said rollers being \ach initially positioned adjacent one end ot the am groove engaged thereby and being adapted to swing in a fixed path about a central. point as its key lever is operated and to traverse said groove, each of said cam grooves being so Formed in its cam piece with relation to the path of the roller cngagi;- ing the same that the traverse (it one roller in its .:am groove will cause the cam piece carrying the same to rotate in one direction and the traverse ot the other roller in its groove will c; use the cam piece carrying said groove to rotate in the other direction, each cam piece being cut away adjacent the normal position o'l the roller lying therein to permit the movement cl? one cam piece with respect to the roller engaging its cam groove when the lever carrying the other member is operated, connections whereby the relative movement oi" the cam pieces is transmitted to said lever arm, and means ior indepcmlenll v changing the direction ot the paths in which said rollers swing.

4-. ln a t-ypinmiter, a. vcrlicallv movable carriage carrying a platen normally located in a mid position, a movable lcvcr arm, means connecting the said arm with said carriage for shifting the same to a higher or lower position in response to a predetermined movement of said lever arm, a pair of cam pieces having cam grooves formed there/n, a pair of key levers carrying rollers and engaging said cam grooves, said rollers being each normally positioned adjacent one end of the cam groove engaged thereby and being adapted to swing in a fiXed pat-h about a central point as its key lever is operated and to traverse said groove, each of said cam grooves being so formed in its cam piece with relation to the path of the roller engaging the same that the traverse of one roller in its cam groove will cause the cam piece carrying the same to rotate in one direction and the traverse of the other roller in its groove will cause the cam piece carr' ing said groove to rotate in the other direction, each cam piece being cut away adjacent the normal position of the roller lying therein to permit the movement of one cam piece with respect to the roller engaging its cam groove when the lever carrying the other member is operated, connections whereby the rotat-ive movement of the cam piece is transmitted to said lever arm, and means for independently changing the point about which each roller swings.

5-. The combination with a key lever having a key and carrying a cam engaging member adapted to swing in an upwardly inclining path, of cooperating supports for said. lever; one support being vertically fixed and controlling the height of the lever key and the other support having capacity for vertical adjustment in position and con trolling the inclination of said path through change in its vertical position.

6. The combination with a key lever having a key and carrying a cam engaging member adapted to s *ing in an upwardly extending path, of cooperating supports for said lever, comprising a vertically fixed support carrying said lever at a fixed height and having capacity for lateral play with respect thereto, and a vertically adjustable support controlling the lateral position of said lever and having a capacity for vertical play with respect thereto and determining by its position of adjustment the point about which the cam engaging member swings.

7. The combination with a key lever having a key and carrying a cam engaging member adapted to swing in an upwardly extending path, of cooperating supports for said lever, comprising a vertically fixed support carrying said lever at a fixed height and having capacity for lateral play with respect thereto, and a vertically adjustable support controlling the lateral position of said lever and having a capacity for vertical: play with respect thereto and determining'by its position of adjustment the point about which the: cam. engaging member swings, said adjustable support being movable in an are described about a fixed point on said lever as a center.

8. The combination with a key lever having a key and carrying a cam engaging roller, of supporting means for said lever comprising a bracket, a supporting screw or stud fixed on said bracket and engaging said key lever with a capacity for lateral movement with respect thereto, a stud slidable upon said bracket and securable therein in various positions of vertical adjustment, and link pivotally attached at one end to said stud and at the other end to said lever, said stud being movable upon said bracket in an are centered at the point of attachment of said link with said lever.

9. In a typewriting machine, or the like, the combination, with a movable platen normally located in an initial position, mechanism for shifting said platen to another position, such mechanism including a member carrying a cam surface and a cooperating member engaging said cam surface and adapted to slide therein, one of said members being arranged to swing in a prescribed path and being adapted in the course of such swing to effect a shift of the other or shiftable member into a predetermined location; of means for changing the direction of the path taken by said swinging member after leaving its normal position to vary the shifted. position of the shiftable member..

10. In a typewriting machine, or the like, the combination, with a movable platen normally located in an initial position, mechanism for shifting said platen to anther position, such mechanism including a member carrying'a cam surface and a cooperating member engaging said cam surface and adapted to slide therein, one of said members being arranged to swing in a prescribed path and being adapted in the course of such swing to eifect a shift of the other or shiftable member into a predetermined location, and means for communicating the movement of said shift-able member to the platen; of means for displacing the path of the movement of said swinging member to vary the shifted position of the shiftable member.

11. In a typewritingv machine, or the like,

the combination, with a movable platen normally located in an initial position, mechanism for shifting said platen to another position, such mechanism including a member carrying cam surface and a cooperating member engaging said cam surface and adapted to slide therein, one of said members being arranged to swing about a central point and being adapted in the course of such swing to effect a shift of the other or shift-able member into a predetermined location, and means for communicating: the

movement of said shiftable member to the platen; of means for changing the location of the point about which said swinging member turns to vary the shifted position of the shiftable member.

12. In a typewriter, a movable platen normally located in an initial position, a cam piece having a cam groove formed therein, a key-lever having a portion engaging said cam groove, said portion being adapted to swing in a prescribed path as said key-lever is operated and in such swing to traverse said cam groove, said groove being so formed in the cam piece with relation to the swinging portion of the key-lever engaging the same that the traverse of said portion in the cam groove will cause the cam piece to rotate, connections whereby the rotative movement of said cam piece communicates a shifting movement to the platen, and means for displacing the path of the movement of this swinging portion of said key-lever to vary the amount of rotative movement of said cam piece.

13. In a typewriter, a movable platen normally located in an initial position, a cam piece having a cam groove formed therein, and a key-lever having a portion engaging said cam groove, said portion being adapted to swing about a central point as said keylever is operated and in the course of such swing to traverse said cam-groove, said groove being so formed in the cam piece with relation to the movement of the swinging portion of the key-lever engaging the same that the traverse of said portion in the cam groove will cause the cam piece to rotate, connections whereby the rotative movement of said cam piece communicates a shifting movement to the platen, and means for changing the location of the point about which the said key-lever swings to vary the amount of the rotative movement of said cam piece.

In testimony whereof I aflix my signature in presence of two witnesses.

ARTHUR W. WEEDEN. Witnesses:

NATHAN B. DAY, CHAs. F. RANDALL.

Copies 01' this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. 0."

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