US2875880A - Cycling device for power driven typewriters - Google Patents

Description

March 3, 1959 L. EPALMER 2,875,880

CYCLING DEVICE FOR POWER DRIVEN TYPEWRITERS Filed Dec. 29, 1954 I 2 Sheets-Sheet 1 LEON E. PALMER W @112 avo ATTORNEY INVENTOR.

L. E. PALMER March 3, 1959 E FOR POWER DRIVEN TYPEWRITERS CYCLING DEVIC Filed Dec. 29, 1954 2 Sheets-Sheet 2 INVENTOR. LEON E. PALMER wwm ATTORNEY 2,875,880 Patented Mar. 3, 1959 ice CYCLING DEVICE FOR POWER DRIVEN TYPEWRITERS Application December 29, 1954, Serial No. 478,240 Claims. (Cl. 197-17) This invention relates to typewriters and more particularly to a device for controlling the cyclic operation of the power operated mechanisms of a. power driven typewriter.

In average typing, a typist will operate at a rate of approximately 10 characters per second, but when she deals with familiar words wherein the fingers seem to work automatically, it is reasonable for her to get up to speeds of 20 or 30 characters per second. In some instances, during this flurry typing, wherein familiar words are typed at a much higher rate than average, two type bars will be driven towards printing position with such a short time interval between them that the second bar will clash into the first one. For this reason, it has been necessary to make type bars of very sturdy expensive material, and it has been necessary to provide type bars with bumpers positioned to engage the intercharacter space of a colliding type bar to prevent mashing of the type faces.

It can be appreciated, that if the type bar driving rate could be controlled to prevent type bar clashing, it would be possible to use a less expensive material and thereby reduce the cost of type bar construction. Accordingly, it is a first object of this invention to provide a new control for a power driven typewriter, wherein the type bars will be driven to printing position, in a predetermined or pre-selected cyclic operating time.

It is a further object of this invention to provide a control for power driven mechanism of a typewriter that will prevent end clashing of type bars.

In dealing with power driven typewriters, another problem is to make sure that the carriage has spaced the proper distance, that is, the pitch distance between the rack teeth before a character is printed. If the carriage has been properly spaced, then over printing will be prevented and character spacing will be correct thereby meeting the rigid requirements of modern business.

Accordingly, it is a still further object of this invention to provide an improved synchronizing mechanism for a power driven typewriter operable to insure correct inter-character spacing.

Another object of this invention is to provide an improved synchronizing mechanism for a power driven typewriter operable to insure a suitable frequency of operation of machine functions.

In conventional power driven typewriters, it is recognized in the art that a ribbon vane is operated at every print stroke to feed inking ribbon past the printing position. The ribbon vane is operated by the type bar driving mechanism, while the escapement mechanism above mentioned, is operated by the type bar itself. In the latter instance, the type bar in its flight towards the typewriter printing position strikes a well known U-bar which operates the escapement mechanism. If a second type bar is driven towards printing position, before the ribbon vane or the U-bar respectively have been restored to their rest positions, then the type bar driving mechanism, or type bar must overcome the momentum of the ribbon vane tion with respect to a shoulder 26 of the cam and/or U-bar, bring it to a halt and then reverse its direction towards operative position. When the momentum of these parts has to be overcome, an additional load is placed on the type bar and/or its driving mechanism which diminishes the striking force with which the type bar prints, thereby reducing the color density of the character printed, since the color density is proportional to type bar speed.

Accordingly, it is a still further object of this invention to provide a new synchronizing control for a power driven type bar wherein the U-bar and ribbon vane will have been restored to their rest positions before a second type bar can be driven towards printing position.

Other objects of the invention will be pointed .out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principle of the invention and the best mode, which has been contemplated, of applying that principle.

In the drawings:

Fig. 1 is a perspective view of an improved cycling device shown with a type bar driving mechanism.

Fig. 2 is a side elevation of the mechanism shown in Fig. 1.

'Fig. 3 is a section through plane 3-3.

Briefly, this invention relates to an improved synchronizing control for a power mechanism of a typewriter, wherein the depression of a key lever operates an interposer that releases a cyclic driving device, which controls the operation of the power driven mechanism for any type bar so that there is a maximum operation of one type bar being driven towards printing position every 60 milliseconds thereby giving a type bar, the ribbon vane and U-bar time to get from the rest position to operative position and return before a second type bar is operated.

Referring to the drawings, the well known motor driven power roll 2 of an IBM typewriter is shown mounted for a continuous clockwise rotation. A key lever 4 is shown pivotally mounted about a bearing point 6 for movement into and out of operative position under control of a key button 8. Actually, the key lever is provided with an operating finger 10 which engages a bent over car 12 of an interposer trip latch 14, which is pivotally supported by a pin or shaft 16 for both pivotal and transverse motion within the limits of a slot 18. The pin 16 extends across the typewriter to support a plurality of individual trip interposers, one for each of the power driving mechanisms of the typewriter.

\Vhen the trip interposer 14 is pivoted about the pin 16, a rearward extension 20 engages a bail 22 while a cam ear 24 simultaneously is moved into operative posi- 28. While in its operative position, if the cam car 24 is pulled transversely to the left, as viewed in Fig. 2, it will strike' shoulder 26 to rock the cam 28 counterclockwise about a pivot pin 30 carried by a cam lever 32. Such an operation, as is well understood in the art, will move a serrated surface 34 of the cam 28 into driving engagement with the power roll 2, and since the cam has an ever increasing radius with respect to its center 30, the cam lever 32 will be rocked counterclockwise about its pivot support 36 thereby moving its outer end 38 counterclockwise about the pivot pin 36 and in opposition to a spring 39 which motion is utilized in a well known mane net to drive a type bar into printing position.

Bail 22-is pivotally supported in the typewriter frame:

by rivets or stub shafts 40, 42 and accordingly, when the interposer extension 20 engages the will be rocked clockwise with respect to belt or other suitable driving means 46 to a pulley bail 22, the latterthe rivets 40, 42.

A pulley 44 which is mounted for rotation in response to the operation of the power roll, is connected by a amid until the second'ear omega-a sp'rin'g'clutch so, drives an auxiliary ainSWWhichis rotatablymount d on a hub 53 f pulley 48 and engages one end of the-spring of clutch-50 and is-norm'ally blocked from rotation by a trip latch 56 which is pivotally supported on the rivet or stub shaft that mounts one end of the bail 22. When" bail 22 is pivoted about'its' supporting rivet '42, however, an arm 58 of the trip latch {56 which underlies can 22, is roeked eloekwise in opposition to "the force of af'spring 60 thereby lifting the no'se 62 o f th'e "trip latch 56 out ofth'e path or the two lobe cam 54. As this action' takes place, there "is no longer'fa restraining force the cam54, therefore-the spring clutch 'will grip the hub 53 to rotate=shalftf52clockwise in Fig. 1 undenthe influence oflth'e pulley '48. g g The shaft 52 has rigidly attachedthereto,a fluted member 64, which provides a pair of oppositely disposed flutes 66, 68 which normally are @free to rotate'withshaft 52 clear of anyof the hooks 70 of any of the trip ititerposers '14. However, ifone of the trip interposers has been pivoted clockwise about its supporting .pin 16, under the i nfiuence of the key 'leve'r trip 'finger'lO, then t'hefhook -'70 is in the path of one of the flutes 66, '68 whereupon, during: the rotation of shaft '52, "a flute will engage the hook 70 pulling i upon the'shoul'd'er 26 of 'the latter into engagementwith the "power 'rollto institute a driving eyclefor the cam lever 32 and its associated type ba'r (not shown). v

-As the trip 'interposer is drawn transversely in the direction of the arrow under the influence of 'one of the fiutes 66, 68, the ear 12 will be drawn behind the finger whereupon a spring 72 rocks the. trip "interpos'er 14 counterclockwise about-pin 16 to "disengage hook 70 from the engaging flute, and movethe extension 20' up into engagement with a stop 74 supported by some means, not shown, on the typewriter frame. If, perchance, the operator has not taken her finger olf key button 8, then since trip interposer l4 was rocked counterclockwise by spring, 72, the ear-12 will be blocked by the trip finger 10 and consequently, the trip interposer 14 cannot be restored to its restpositionshownin the drawings. How. ever, when the operator lifts her finger from key button 8, the key lever 4 will be raised to its rest position, whereupon spring 72 will restore the trip interposer 14 to its rest position shown in Figs. 1 and 2 whereupon it Will-be readyfor an operating cycle the next time its associated key lever is depressed.

With reference again to the two ea'red cam '54 which isirotatably mounted on the hub 53, it will be noted that the trip latch 56 is first rocked clockwise to permit an eat 78 of the cam 54 to' ride under the nose 62, then when=lpressure is removed from bail 22, the spring 60 willapull "the nose 62" into :peripheral contact with the 76 abuts the nose 62 thereby 'disengaging the shaft 52 from the hub 53 and pulley 48 hy unwinding the spring clutch 50.

specifically the spring clutch 50*comprises the ttro IOBedeam' SE-and the single lobed cain 55 intercom seetea'bymm of a coil'spring-SZ Cam 54 is free abouthub 53 while 55 is pinned to shaft '52. A "is moun'tcdc'onveniently on "the typewriter frame toien ga'ge the lobe on earn '55 to prevent it from turncoun'te'rclockwisedirection (as viewed in Figs. 1' 2). -The 'ai'ran'gementbf is 'eu'ch tharwhen 15638 0 5 engages the lobe. onc amIS S and when the nine of trip-lateh- 56 engages" one. of the lobes onlc'am' 54, the coil spring 57 is unwound thereby permitting pulley 48 andhub 53 to rotate freely of the spring clutch and, consequently, of shaft52. When nose 62 is lifted away from the lobes on cam 54, spring 57 tightens toward its normal diameter and grips hub 53 to drive shaft 52 via cam 55. When one of the lobes of cam 54 again engages nose 62, the-lobe on cam 55 normally would not have travelled far enough to get under the stop 59, but the momentum of the cam is sufficient to unwind the spring 57 enough for the lobe on cam 55 to engagethe stop 59, thereby unlatching the spring clutch.

It will be noted too that the bail '22 is rocked, notby thekey lever directly but rather-by the key lever acting through the trip interposer 14. More specifically, the extension 20 rock's' the-bail22 and consequently, as soon as one of the flutes 66, 68 picks up the hook 70 to move the trip interposer transversely of pin 16 in the direction of-th'e airow,--'the eiiten'sion 20 will be slid'o'if the bail 22, wherea en ihe -s'pring"60"will" actto interposie the nose 62 "to block cam-54 ana 'resterethe bail 22 to it's rest position. In this respect, the flutes 66, 68 are in alignment with the ears 76,-'78 on the cam"54 but rather are advanced so thatthe eXteiision 20" *of"trip inposer will keep the second half revolution of cam 54,

, a half revolution,

terposer 14 will have been disengaged '-frorn"the;-bail 22' long before cam '54 makes a half revolution. accordingly, spring '60 will act to restore bail '22 and position nose 62in peripheral-contact "with cam *54 to engage the aextear 76, 78 thereby releasing spring clutch 50,

If a second key lever has been depressedfbefore the spring 60 restores the trip latch "56', the transverse moveinent ofthe first trip interposer will slide its"exteiision 20 offbail 22, but the extension of the 'sec'on'd trip 'inte'rthe bail 22 rocked to its'operative'po'sition blocking the effect of spring 60. Under these Eircumstances, cam 54 will make another half revolution since nose 62 will not be in its blocking position. During one of the flutes 66, 68 will pick up the book of the next succeedingt'rip interposer to institute another type bar drive action. The time between any 'two successive type bar drive actions will be 'that period of time it takes the shaft 52 to make and the free speed of shaft 52 is regulated to be 500 --R. P. M. or one half revolution every 60 ms.

The timing of the mechanism is such that approximately 10 milliseconds elapses from the depression of a key lever until the next succeeding flute, for. example, the flute 68, Figs. 1 and 2, engages'the hook 70 of'the tripinterpos'er that the key lever has rocked to operative'po'sition. Accordingly, if a second key "is depressed 10 milliseconds later "than the first key, or'any time thereafter, then the cyclic operation 'of the type bars being 'driven'into printing position will be governed bythe half revolution rate of shaft 52. Since 10 milliseconds between key lever strokes is a rate of approximately 100 a "second, which is practically'impossible to attain, ithas been found that for all'practical purposes, this improved cyclically controlled operation prevents all clashing of type bars and under any circumstances, it minimizes collision of type bars of the sort that would damage "the type faces.

It is admitted that it is possible to depress two keys sion whieh does'not have the deleterious or type smashing effect that is produced when the type face of a second't'ype ba'rs'trike's a first type bar.

Whilethere have been shown and described and'pointed out the fundamental novel features of the"invention, as appliedlto a preferred embodiment, it vvill be understood that various omissions and 'substitutions and changes in v the term and details of the device illustrated and in its v H A bythose skilledin'the artwithout departingfroin the spirit of the invention. It isthe inten V tion, therefore, to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. In a typewriter having a type bar and a power driving mechanismoperable selectively to drive said type bar to printing position, a cycling ,device for regulating the timing between type .bar print strokes comprising a fluted shaft, means mounting the same for rotation, selectively operable means for connecting said fluted shaft for driving relation with a power source, a trip lever having a flute hook mounted in said typewriter for both pivotal and transverse movement, a key lever for selectively pivoting said trip lever into engagement with the fluted shaft, means operable in response to the rocking of said trip lever for operating said fluted shaft connecting means to provide for the rotation of said fluted shaft and the consequential transverse movement of said trip lever, and means responsiveto a transverse move ment of said trip lever for conditioning said power driving mechanism to drive a type bar into printing position.

2. In a typewriter having a type bar, a power driving mechanism selectively operable to drive the type bar to printing position, a cycling device for regulating the timing between type bar print strokes comprising a shaft having a flute thereon, means mounting the same for rotation, clutch means selectively connecting said fluted shaft to a power source, a trip lever having a flute hook mounted for pivotal and transverse movement, a key lever positioned for engagement with said trip lever to rock the latter into position to be engaged by said flute of said fluted shaft, means responsive to the pivoting of said trip lever for operating said clutch means to connect said fluted shaft to the power source thereby driving said trip lever transversely in response to the rotation of said fluted shaft, and means responsive to the transverse movement of said trip lever for actuating said power driving mechanism to drive a type bar into printing position, whereby the cyclic rate of operation of said power driving mechanism is controlled by the rate of rotation of said fluted shaft.

3. In a typewriter having a type bar, a power driving mechanism selectively operable to drive said type bar to printing position, a cycling device for regulating the rate of selective operation of said power driving mechanism comprising a shaft having a flute thereon, means mounting the shaft for rotation, clutch means interconnecting said shaft with a continuously rotating power source, a trip lever having a flute hook mounted for pivotal and transverse movement whereby said trip lever can be pivoted into the path of the flute on said shaft, means responsive to the pivotal movement of said trip lever for operating said clutch means, a key lever, means responsive to the operation of said key lever for pivoting said trip lever to operate said clutch means to engage said fluted shaft with said continuously rotating power source with the inter-engagement of said flute and said trip lever moving the latter transversely, and means releasing the said trip lever from said flute after a predetermined transverse movement, said trip lever having integral means operable in response to the transverse movement of the trip lever for conditioning said power driving mechanism to operate through one cycle, whereby sequential power driving mechanisms are operated at a rate controlled by the rate of rotation of said fluted shaft.

4. In a typewriter having a type bar, power driving mechanism operable selectively to drive the type bar to printing position, a cycling device for regulating the rate of operation of said power driving mechanism comprising a shaft having a flute thereon, means mounting the shaft for rotation, clutch means selectively operable to interconnect said fluted shaft and a power driving source, a trip lever having a rest position and an actuating position, key lever means operable to move said trip lever from its rest to its actuating position, means responsive to the movement of said trip lever into its actuating position for operating said clutch means to drive said fluted shaft and for interconnecting said trip lever with said fluted shaft, means responsive to the interconnection between said trip lever and said fluted shaft for operating said power driving mechanism, and means releasing said trip lever from said fluted shaft after said power driving mechanism has been actuated.

5. In a typewriter having a plurality of type bars, individual power driving mechanism for said type bars selectively operable to drive a respective type bar to printing position, a cycling device for regulating the timing between sequential operations of said power driving mechanisms comprising a plurality of trip levers one for each of said power driving mechanisms, a shaft having an elongated radial flute thereon, means mounting said fluted shaft transversely of said trip levers, clutch means selectively operable to interconnect said fluted shaft with a power driving means, individual key lever means operable to rock an associated trip lever into engagement with the said fluted shaft, a bail positioned transversely of all of said trip levers, means interconnecting said bail and said clutch means for operating the latter to drive said fluted shaft in response to the rocking of a trip lever, and means responsive to the inter-engagement of said trip lever and fluted shaft for actuating the associated power driving mechanism to drive a type bar to printing position whereby the rate of operation of said trip levers is controlled by the rate of rotation of said fluted shaft.

6. In a typewriter having a power driving mechanism, an improved printing rate control for regulating the periodicity of print strokes comprising a shaft having a flute thereon, means mounting the same for rotation in the typewriter, selectively operable means for connecting said fluted shaft for driving relation with a power source, a trip lever having a flute hook thereon, key lever means for engaging said trip lever hook with said fluted shaft, means operable in response to said engaging for connecting said fluted shaft with said power source, and

' means operable in response to the consequential rotaacting through said trip lever driving mechanism to effect a tion of said fluted shaft for actuating said power print stroke.

7. In a typewriter having a plurality of type bars, power driving means, individual cam means operable when coupled to said power driving means to drive a respective type bar to print position, engaging means operable to selectively engage a predetermined one of said cam means with said power driving means, a cycling device operable when actuated to operate said engaging means and thereby cause a selected type bar to be driven to print position, and a key lever operable both to condition a predetermined engaging means for operation and to actuate said cycling device.

8. In a typewriter having power driving means, cam means operable when engaged with said power driving means to perform a typewriter function, a cycling device operable for limiting the rate of successive engagements of said cam means with said power driving means, means operable for engaging said cam means with said power driving means and a key lever operable both to actuate said cycling device and to engage said operable means with said cycling device for operation thereby.

9. In a typewriter having power driving means, individual cam means operable when engaged with said power driving means to perform typewriter functions, a cycling device operable for limiting the rate of successive engagements of said cam means with said power driving means, means operable selectively to engage corresponding said cam means with said power driving means, and a plurality of key levers operable for actuating said cycling device and for engaging said operable means with said cycling device for operation thereby.

10. In a iypewriter having :.power driving means,.cam meansoperable; when e'ng agad-with said pown'di'iving means for performi-ng a typevvritefffunbtioh a trip 'l'evi' having; a rest position and a co ridition e d iabs'it'ion and oporable in said conditioned position for Engaging said cam p eanswit h said power driving means, ake'y lever operable for moving said t riia Iver fronilsaid 'rest pos'ition to said conditioned position, a Cycling 'd'vic opcrablea for operating said conditioned -trip lvei' and for limiting fherate of siiccssive engagements 'of said Cam mansfivith said 'pow r driving means, and means oprable in response to. the movement of said tip. lover. to

said conditionedbdsitioi for a tiia'tihg said eyeing 'devf.

Rgferences Cited in the file o f his paieiit

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