US2633223A - Silent key mechanism for typewriters - Google Patents

Description

March 31, 1953 A. c. ZEAMER 2,633,223

SILENT KEY MECHANISM FOR TYPEWRITERS Filed Aug. 11, 1950 2, SHEETS-swam 1 AARON C. ZEAME R INVENTOR ATTORNEY March 31, 1953 I y A. c. ZEAMER SILENT KEY MECHANISM FOR TYPEWRITERS 2 SHEETSSHEET ,2

Filed Aug. 11, 1950 my 8, 3 X m mm M W r 5 f ,fr mm w mm gen 7 mm a W me 7 2 PM w m T Hm mm AARON C. ZEAMEIR INVENTOR ziBY v f ATTORNEY V Patented Mar. 31, 1953 UNITED STATES PATENT OFFICE SILENT KEY 'MECHANISMFOR TYPEWRIT-ERS Aaron 0. vZeam-er, Groton, N. 56., assignorto 'L. C. .Smith -& Corona Typewriters, Inc., Syracuse, L'N.'Y., a corporation of New 'York '2Application August11, 195o, :s.-eria12Nn.:rcsnoo critical marks.

A further object of the invention ;is to .;provide an improved and simple arrangement of type ac- 'ticnszand of a type action actuated universal bar randribbon vibrating ,means and carriage feeding :escapement :means operable "by said universal bar wherebya-ny one :or more selected. ones of the {type actions may beadapted for printing actuation without actuating the escapement meanslland whereby the throw of the universal bar .anay be very accurately and positively controlledcby each :of the selected type actions to cause the ribbon vibrator to move sufiiciently to cover ethe ;printi-ng point of the machine and at the same time prevent the universal bar from beingvmoved far enough to actuate the escapementsmeans.

A :f-urther object of the invention is to provide a silent typebar action-which will itselffirstrdrive and then positively arrest an escapemen-t tripping universal bar before driving said bar .far enough to trip the escapement.

\A tfurther object {of the invention is to provide a silent tf'ype bar v:action operable on an escapement ,trmping {universal bar at any point along the universal .bar to positively block :escapement trippingaction of the universal bar Without canting or twisting the universal bar.

A .furtherxobject of the invention :is to provide atypewriter having an improved-silentkey mechanism for positively blocking letter feeding :actionsof :the machine and also for =positively eontrollingthe operation of :assilent type bar action to reduce or limit the impact, force of the special type controlled by: the action.

.A further object of the invention .is to provide a visible typing typewriter having improved and simple means whereby any desired type bar action or actions of a typewriter may be readily converted to silent type bar actions which print with less force and through a different widthwise zone of the inked ribbon of the machine than do the other type bar actions.

(Other objectsand advantages of the invention will appearcfrom the iollowing description of the .2 preferred embodiment of the invention illustrated in the accompanying drawings.

in :the drawings :Figure ;1 is a fragmentary top plan view of a visible typing typewriter embodying the invention;

Fi ure 12 is a 'sectional view on the :line 2-2-oi Figure :1

Figure 3 is a detail sectional viewon-the line 33 of Figure -6 showing parts of the. escapement tripping means in their :escapement tripping position;

Figure 4 is a detail sectional view on the line 4-4 of Figure 1 vshowing the escapement .rin tripped position;

Figure .5 .is a detail view showing parts ofithe ribbon vibrator actuating and escapement tripping linkag and Figure '6 is a sectional view .on the line 6-6 of Figure l.

The improvements are shown embodied .in an otherwise known portable typewriting machine only so .much .of which is illustrated and will .be described as is necessary to .enable'those skilled in the .art to understand the present invention. Said fknown .machine has amain supporting framework l 0 for its moving parts. Mounted on this framework Illistaset of 'key operated type bar actions only some of which ares'hown. Each type bar action consists of a sheet metal key lever H pivoted on ared 12, a sheet metal qsublever 13 pivoted on a rod l land having upperand.

lower arms, a type Tbar l5 piv oted on .an arcuate pivot wire 16 in a type bar'segment 11, a 'wire link [8 connecting theflower arm of "the sub-lever with the type bar and a type bar action return spring 19 connected to the flower arm of the sublever iand to framework [0. The keyflevers areo'f bellcrank yiornneach having :a forwardly extending key carrying arm and a pendant arm. The pendant arms of the key levers are engaged in front of the upper arms of the sub-levers. The key levers are normally held rocked against a stop illla onframework Ill and the type barsare' connected with an escapement ratchet wheel 26, said pinion and wheel being rotatively journaled on bracket 23. An escapement dog rocker 21 is provided with a fixed dog 28 and a pivoted dog 29. Dog 29 is pivoted on the rocker at 30 and is connected with the rocker by a spring 3| which normally holds the dog rocked against a stop 32 on the rocker. A dog rocker return spring 33 is connected with the bracket 23 and the dog rocker and normally holds the rocker arrested in the position shown in Figures 1 and 6 by a stop 34 carried by the bracket. In this normal position of the rocker the dog 28 is below theplane of ratchet wheel 23 and the dog 29 is engaged with a tooth of said ratchet wheel. The rocker is pivoted on the bracket at 3535 and is trippable about its pivot into the position shown in Figure 4 to disengage dog 29 from the ratchet wheel and engage dog 28 with the wheel. Tripping move-' ment of the rocker is arrested by engagement of a stop portion 33 of the rocker with bracket 23, as shown in Figure 4.

The known machine also has a part 31 fixedly held to the main framework Ill, and has a ribbon vibrator or ribbon guide 38 slidably held to said part for reciprocation substantially in an up- Wardly and rearwardly inclined plane in front of the platen 20 to vibrate the inking ribbon 39 of the machine to cover and uncover the printing point of the machine. The ribbon is attached to the usua1 left and right hand ribbon spools (not shown) which are actuative to feed the ribbon back and forth through the vibrator.

The improvements, as shown, whereby the known machine is adapted to type ordinary and silent characters conveniently and speedily now will be described.

. The keys shown for the ordinary type actions are designated 40 and those for the silent type actions are designated 40a.

A sheet metal universal bar of bail-like form has two integral end portions or side arms lla. pivoted on the pivot rod I4 and has its main portion or cross-bar ll extending horizontally across 7 the machine in front of the lower portions of the sub-levers I3. This universal bar is normally urged by gravity to engage its cross-bar against the forward edges of pendent lugs [3b of the sublevers l3 which form parts of the type actions which actuate the ordinary types. The sub-lever l3 of each of the silent type actions preferably has the front edge of its pendent lug [3b cut back as shown at [30 so that the front edge of said lug is normally spaced slightly rearward from the universal bar. The sub-lever lugs are permanently bendable toward and from the universal bar for adjustment. The cutting back of the lugs 13b of the silent type action sub-levers is advantageous in the machine shown for reducing the throw imparted to the universal bar by those sublevers.

A sheet metal link 42 extends fore and aft of the machine adjacent the right hand side of the machine and is pivoted at 43 to the right hand sidearm of the universal bar below the level of pivot rod l4 and also is pivoted at 44 to a pendent rock arm 45 fixed to a horizontal rock shaft 46. Shaft 43 has reduced end portions journaled at 41 and 48 respectively on the shift frame 22 and the bracket 23 fixed to said frame. Adjacent the medial fore and aft vertical plane of the machine the shaft 46 has fixed thereto a second pendent rock arm 49 to which there is pivoted at 50 a for- Wardly extending sheet metal link 5|. The front end of link 51 is pivoted at 52 to the lower and 4 rearward end of a ribbon vibrator reciprocating lever 53. Lever 53 extends upwardly and forwardly from link 5| to the lower end of the ribbon vibrator 38. The lever is pivoted between its ends on bracket 23 by a horizontal pivot 54 and has its foremost and higher end pivoted to the lower end of the ribbon vibrator 38 by a horizontal pivot 55.

It will be obvious from the foregoing that the universal bar is positively connected with the ribbon vibrator to vibrate the ribbon. The escapement is also adapted to be tripped by actuation of the universal bar by escapement tripping means which now will be described. This escapement tripping means, as more fully hereinafter explained, is ineifective to trip the escapement to letter feed the platen carriage when any one of the silent type keys is actuated.

An escapement tripping lever 56, which extends tranversely of the machine and is pivoted on the bracket 23 by a pivot element 51, has its left hand arm engaged in a hole 58 in the dog rocker 21 above the dog rocker pivot 35 and is normally held rocked by the dog rocker and the dog rocker return spring 33 into a position in which its right hand arm is spaced a short distance forward of a forwardly facing shoulder or abutment 59 formed on link 5 I, as more clearly shown in full lines in Figure 2. It will be obvious that when the tripping lever 56 is rocked into the position shown in Figure 3 by thrust action of the shoulder 59 it will rock the dog rocker into the tripped position shown in Figure 4 to letter feed the platen carriage.

Whenever the key 40 of one of the ordinary type bar actions is depressed far enough to drive its connected type bar to strike the platen, as shown in dotted lines in Figure 2, the sub-lever I3 of that type bar action drives the universal bar 4| into the position shown in dotted lines in Figure 2. This movement of the universal bar lifts the ribbon vibrator and ribbon beyond the position shown in dotted lines in Figure 6, in which the upper half of the ribbon covers the printing point, into a position in which the lower half of the ribbon covers the printing point of the machine, the vibrator and ribbon reaching the lifted position shown in Figure 6 as, or just before, the shoulder 59 on link 5| makes contact with the escapement tripping lever 56 and. as the universal bar reaches the position shown in dotted lines in Figure 6. As the universal bar thereafter completes its movement into the position shown in dotted lines in Figure 2, the shoulder 59 rocks the lever 56 and trips the escapement while the ribbon vibrator and ribbon rise to cover the printing point with the lower half of the ribbon and the actuated type bar completes its printing stroke.

Each silent type bar action is operable to print through the upper half of the ribbon without tripping the escapement. Referring particularly to Figures 1, 5 and 6, the key lever of each silent type bar action is provided with a flat sheet metal stop bar 60 pendent from the forwardly extending key-carrying arm of the key lever. While the stop bars 60 obviously may be formed integrally with the silent key levers they are in the construction shown welded at their upper ends to the key levers at 6|. Each stop bar 69 has a rearwardly extending lower end portion 69a for abutment as hereinafter described with the forward edge of the universal bar 4|. Portion 60a of each stop bar is preferably of reduced width as shown to facilitate up and down bending adjustments of said portions to accurately regulate the point of collision of the universal bar and the respective stop barstt. The stop bars tllare normallyout of the path of movement of the'universal-bar ll :and offer no obstruction to 'full driving of the universal bar bythe ordinary type bar actions.

When any silent type bar action is actuated its stop bar 69 'moves downward andrearwardinto the pathof upward and forward movement-of the universal bar by the sub-*levenof that type bar action. As,=or just before, the shoulder=59 makes contact with the escapement tripping lever -56, as shown in 'olotted'lines of Figure 5, the universal barancl stop bar-60 of theactua'tedsilent type bar action collide, as shown in dotted lines in [Figure 6, and the universal bar is positively gripped at substantially directly opposite points along its front and rear edges between stop bar 60 and the universal .bar driving .lug H?) of the sub-lever of the type bar action. The key lever and subelever of the type lbar action and alse the universal bar thus are all positively arrested .in the positions thereof indicated :in dotted lines in Figure 6. No matter how violent or strong the force applied to the key may be, the universal bar can not swing or be swung beyond this point of arrest nor will the universal bar be twisted or canted by key lever pressure or sub-lever pressure. The ribbon vibrating linkage thus'will be positively arrested in the position shown in dotted lines in Figures and 6 and prevented from tripping the escapement. In this arrested position of the ribbon vibrating linkage the ribbon vibrator and ribbon are held in the partially lifted position shown in dotted lines in Figure 6 with the upper half of the ribbon covering the printing point.

The arrest of the universal bar by stop bar Bil of each silent type bar action occurs as the type bar of the silent type bar action reaches the position shown in dotted lines in Figure 6 from which position it is movable by momentum to print. All silent types print through the upper half of the ribbon and with less force than do the ordinary types which print through the lower half of the ribbon. Silent types have a tend ency to cut the ribbon and to print heavier than ordinary types. In the construction shown, the silent types print with less force than the ordinary types and print through a different widthwise zone of the ribbon.

The ribbon feeding mechanism, not shown, of the known machine in which the improvements are shown embodied may be operable, if desired, from the universal bar M in the improved machine by links 6262 shown in part in Figures 1, 2 and 6.

It will be obvious that any desired number of silent type actions may be provided without ref-- erence to the locations thereof in the set of type bar actions of the machine merely by securing a stop bar 60 to the key lever of each selected type bar action and, preferably, also cutting back the front edge of the lug Hit of the sub-lever of each selected type bar action.

I claim: 7

1. A typewriter having, in combination, ribbon vibrating means, letter spacing means, a universal bar drivable through one extent of throw to effectively actuate both the ribbon vibrating means and the letter spacing means and drivable through a fixed lesser extent of throw to effectively actuate only the ribbon vibrating means, and key operated type bar actions each having a part directly active on the universal bar to drive said "bar on "the printing strokes of the actions, -ceritain rot-said type bar actions each having -a second part directly engageable with the universal bar-to limit -'dr'i ving of the universal bar 'tosaid fixed lesser extent ol throw.

2. typewriter having, in com'binatiom a un'i-' said key and typ'e barihavinga1part which/arrests the universal bar when theikey "is depressed :and a part which drives the universal lbar against said arrestingpart lbefore athe iuniversa'l barrtrips the escapement :an'd :a fterwsaid vibrator has shifted into its aforesaid positi'on;.-said'=two'.:parts being-arranged for transmission of motion ;-by.:one thereof through the other one thereof to the time bar when the .key is depressed.

3. .A typewriter, .as claimed in :claim :2, wherein said twoiparts of .said :actuating train gareaaarranged for engagementwith:thezuniversal barsat substantially directly :opposed points.

A. A typewriter, :as claimed in :claim '2, WHERE- in said universal bar arresting part is a key lever supporting said key, and wherein said universal bar driving part is a sub-leveroperable by said key lever and having a driving connection with said type bar.

5. A typewriter having, in combination, a diacritical symbol printing type action including a key lever and a sub-lever drivable by the key lever to impart typing strokes to the diacritical type, a ribbon vibrating universal bar mounted to be first driven directly by said sub-lever and then clamped between the key lever and sublever to arrest driving of the universal bar, letter spacing means operable only in response to further driving of the universal bar, and additional type actions operable directly on said universal bar to drive the universal bar beyond its point of arrest by the first-mentioned type action to operate the letter spacing means.

6. A typewriter having, in combination, a universal bar, at least one key operated type action having a part for driving said universal bar and a second part mounted to move on the typing strokes of said action to grip said universal bar therebe-tween at a predetermined driven limit of motion of said universal bar, escapement mechanism trippable by additional driven movement of said universal bar beyond said limit, ribbon mechanism operable to position an inked ribbon for typing therethrough both when said universal bar is driven to said limit and beyond said limit, and additional type actions each operable on said universal bar to drive said bar beyond said limit to trip said escapement mechanism.

'7. A typewriter, as claimed in claim 6, wherein said ribbon mechanism presents one widthwise zone of the ribbon for typing therethrough when said universal bar is driven to said predetermined limit and presents a different widthwise zone of the ribbon for typing therethrough when said universal bar is driven beyond said limit.

8. A typewriter having, in combination, ribbon vibrating means, letter feeding escapement means, universal bar mechanism drivable to first actuate the ribbon vibrating means to effect ribbon coverage of the printing point of the machine and to thereafter trip the escapement means, type bars, key levers, and connections between the key levers and type bars to drive the universal bar mechanism and to actuate the type bars, certain of said key levers each having a portion thereof movable into arresting collision with the universal bar mechanism on the printing strokes of those key levers to prevent tripping of the escapement means.

9. A visible typing typewriter having, in combination, a silent type actuating key lever and a universal bar connected and pivotally mounted for swinging thereof into mutually arrestive abuttive contact on the printing strokes of the key lever, means operable by said universal bar to shift an inked ribbon to cover the printing point of the machine when said key lever and universal bar are swung into such arrestive contact, and escapement mechanism trippable by swinging of the universal bar beyond said point of arrestive contact of said key lever and universal bar.

10. A visible typing typewriter, as claimed in claim 9, having a ribbon vibrator, a link reciprocable by the universal bar and positively connected with the universal (bar and the ribbon vibrator to shift an inked ribbon to cover the printing point of the machine, an escapement 8 tripping lever, and an abutment on said link for actuating the escapement tripping lever and normally spaced from said tripping lever.

11. A visible typing typewriter having escapement tripping means, ribbon vibrating means drivable to shift an inked ribbon to cover the printing point of the machine and thereafter actuate said escapement tripping means, and a diacritical symbol printing type action and other type action each having a driving part for said ribbon vibrating means, said diacritical symbol printing type action including a key lever mounted to move into blocking engagement with said ribbon vibrating means on the typing strokes of the diacritical symbol printing type action to prevent actuation of the escapement tripping means.

AARON C. ZEAMER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,203,255 Petermann Oct. 31, 1916 1,428,325 Davidson Sept. 5, 1922 1,437,241 Harmon Nov. 28, 1922

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