US3598220A

US3598220A - Ribbon-lifting mechanism for a typewriter

Info

Publication number: US3598220A
Application number: US808570A
Authority: US
Inventors: Robert E Mcgrath
Original assignee: Litton Business Systems Inc
Current assignee: TRIUMPH-ADLER AG A CORP OF GERMANY; Western Atlas Inc
Priority date: 1969-03-19
Filing date: 1969-03-19
Publication date: 1971-08-10
Anticipated expiration: 1988-08-10

Abstract

A ribbon-lifting mechanism for a typewriter comprising a toggle mechanism the common ends of whose links are pivotally mounted on a drive arm, the other end of one link is fulcrumed on a bistable shiftable support, and the other end of the other link is pivotally connected to a ribbon lift crank. The drive arm is operable on each forward stroke to open or straighten and on each rearward stroke to close or break the toggle about its fulcrum. A bistable trip lever also pivotally mounted on the drive arm is conditioned on each forward stroke of the drive arm to shift the position of the bistable support on each rearward stroke of the drive arm, and as a result of the shifting movement of the bistable support a ribbon vibrator connected to the toggle mechanism is elevated alternately through full and partial strokes on succeeding forward strokes of the drive arm whereby in combination with ribbon movement a zigzag pattern is defined on a carbon ribbon to utilize the maximum area of the carbon ribbon.

Description

United States Patent 3,171,530 3/1965 ODanieletal............... 197/151 3,348,650 10/1967 Meinherz etal. 197/158 X Primary Examiner- Robert E. Pulfrey [72] inventor Robert E. McGrath Rocky Hill. Conn. 808,570

[21] Appl. No.

gg s 10 I971 Assistant Examiner-Stephen C. Pellegrlno Assign um) Business sysems hm AltomeysJ0seph R. Spalla and Cornelius P. Quinn New York, N.Y.

ABSTRACT: A ribbon-lifting mechanism for a typewriter comprising a toggle mechanism the common ends of whose links are pivotally mounted on a drive arm. the other end of one link is fulcrumed on a bistable shiftable support. and the other end of the other link is pivotally connected to a ribbon lift crank. The drive arm is operable on each forward stroke to open or straighten and on each rearward stroke to close or l A R m m M B m N n m M C 5M E m M 8 G u m m m em NW mnm wYCs RT6U H H U [51] Int.Cl...............r...................................1.....B4lj35/22.

break the toggle about its fulcrum. A bistable trip lever also pivotally mounted on the drive arm is conditioned on each for- Fie 01 ward stroke of the drive arm to shift the position of the bistable support on each rearward stroke of the drive arm, and as a result of the shifting movement of the bistable su pport a rib- [56] References Cited UNITED STATES PATENTS bon vibrator connected to the toggle mechanism is elevated alternately through full and partial strokes on succeeding forward strokes of the drive arm whereby in combination with ribbon movement a zigzag pattern is defined on a carbon ribbon to utilize the maximum area of the carbon ribbon.

3,139,964 7/1964 Fischer........................ 197/157 3.154.185 10/1964 l97/156X PATENTEDAUBIOISYI 9,598,220

sum 1 0r 6 STENCIL CARBON INVENTOR ROBERTE.McGRATH BY M ATT RNEY PATENTED AUG] 0 IBYI I sum 2 UF 6 INVENTOR ROBERT E. McGRATH KLQMQ a? 14 AT ORNEY PATENTEUAUBIOIQH $3,598,220

sum 3 or 6 INVENTQR ROBERT E. McGRATH ATTO NEY PATENIEU AUG] 0 mm SHEET 0F 6 INVENTOR ROBERT E. McGRATH ATTO NEY .ESQHZZO PATENTED AUG] 0 ISYI SHEET 5 0F 6 INVENTOR ROBERT E. MCGRATH yin M44.

ATTO NEY PATENTED AUG 1 0 I971 SHEET 8 BF 6 INVENTOR McGRATH ATT RNEY ROBERT E.

BY (TQM DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention is particularly directed to a carbon ribbon vibrator for use in a typewriter having the capability of switching between, a fabric ribbon operational mode, a carbon ribbon operational mode and a stencil operational mode, in accordance with the typewriter ribbon selector control apparatus described and claimed in copending U.S. Pat. application Ser. No. 808,516, of Ronald H. McLean filed concurrently on Mar. 19, 1969.

Referring now to the drawing wherein like reference characters designate like or corresponding parts throughout the several views, there is illustrated in FIG. 1 a type action, generally designated by the reference numeral 10, operable to power a U-bar 11 adapted to selectively drive appropriate ribbon vibrator assemblies for elevating a fabric ribbon vibrator, generally designated by the reference numeral 12, supporting a fabric ribbon FR and a carbon ribbon vibrator, generally designated by the reference numeral 13, supporting a carbon ribbon CR.

As illustrated in FIG. 1, the U-bar 11 moves counterclockwise about a cross-shaft 14 as will hereinafter appear, in response to type action operation initiated by the depression of alphanumeric key levers such as a key lever 15. The key lever 15 is fulcrumed on a cross-shaft 16 secured to the typewriter frame and is formed with a depending finger 17 engaging the upper surface of a bent off shelf 18 formed on the forward end of a rigid or nonflexible intermediate control lever 19 pivotally mounted on a cross-shaft 20. An angularly extending rearward portion of lever 19 terminates with a tip 21 that normally underlies the lower edge of a tail 22 formed on a rockable cam 23. The cam 23 is pivotally mounted on a sublever 24 of an actuating linkage, generally identified by the reference numeral 25, pivotally mounted on the cross-shaft 14, and is biased in a counterclockwise direction by a spring 26. The counterclockwise limit of movement of the cam 23 relative to the sublever 24 is determined by the engagement of a bent-off ear 23a on the cam 23 with an adjacent edge 24a of sublever 24. The actuating linkage 25 is articulately connected by a link 27 to a type bar 28 pivotally mounted on a segment wire 29 and is adapted to drive the type bar 28 from a normal position on a headrest 30 into printing contact with a typewriter platen 31, and at the same time, through a tail 32, extending from the sublever 24 and overlying the U-bar 11, move the U-bar 11 counterclockwise.

In operation, the rockable cam 23 is displaced in a clockwise direction in response to the depression of the key lever.l5 so as to move into frictional driving engagement with a constantly rotating power roll 33, thereby initiating a powered printing stroke to the type bar 28 and counterclockwise movement of the U-bar 11. After typing impact, the type bar 28 and the sublever 24 are returned to their normal positions by means of a return spring 34, allowing the U-bar 11 to return to a normal clockwise position through the action of a biasing spring (not shown).

The fabric ribbon vibrator l2 and the carbon ribbon vibrator 13 are both positioned behind a type guide generally designated by the reference numeral which is fastened to a shiftable type bar segment 36 by a pair of screws 350. The fabric ribbon vibrator 12 has a pair of bent over ears 12a and 12b in slidable engagement with the spaced

vertical legs

35a and 35b of the type guide 35 and has a depending leg 121' whose lower end is rockably mounted on a stud 37 formed on a lever 38 rigidly mounted on a shaft 39.

The carbon ribbon vibrator 13 has a leg 40 whose upper end is bent and bifurcated forming a slot 40a by which it has guided association with the side edges of the upper portion of the fabric ribbon vibrator leg 12c, and whose lower end is formed in a generally inverted U-shape with its ends rockably mounted on studs 41 formed on a pair of levers 42 rigidly mounted on a vibrator elevating rod 43. Tension in the carbon ribbon, applied by a carbon ribbon drive mechanism (not shown), avoids forward and rearward movement of the carbon ribbon vibrator 13.

As illustrated in FIG. 2, a carbon ribbon vibrator drive assembly, generally designated by the reference numeral 44, is adapted to drive the carbon ribbon vibrator elevating rod 43, in response to counterclockwise movement of the U-bar 11 occasioned by a type action when a ribbon control selector dial 45, shown in FIG. 3 and manually rotatable about a crossshaft 46, is set to a carbon ribbon operational mode.

The carbon ribbon vibrator drive assembly 44 includes a drive link 47 having an elongated slot 48 in its forward end with an upwardly extending notch 480 formed in the rear of the elongated slot 48. A drive pin 49 extending laterally outward from an upwardly extending arm 11a of the U-bar l 1 and into the elongated slot 48, is received in the notch 48a when the drive arm 47 is held downwardly by a biasing spring 50 connected between the drive arm 47 and a frame mounted stud 50a. With the drive pin 49 in the detent 480, any counterclockwise movement of the U-bar 11 about the cross-shaft 14 will drive the drive arm 47 forward.

The detent 48a in the slotted end of the drive arm 47 is adapted to be lifted out of driving engagement with the drive pin 49 by a bellcrank, generally designated by the reference numeral 51, pivotally mounted on a frame-mounted stud 52. The bellcrank 51 has a depending cam follower arm 53 with an enlarged end portion 53a adapted to follow the surface of a cam 54 formed on the ribbon selector control dial 45 (shown in FIG. 3), as the ribbon selector control dial 45 is moved between settings, and another arm 55 with an enlarged end portion 55a underlying a laterally bent-out ear 56 on the bottom of the forward end of the drive arm 47. When the ribbon selector control dial 45 is moved from a carbon ribbon operational mode, the cam 54 pivots the bellcrank 51 counterclockwise, as viewed in FIG. 2, raising the slotted end of the drive arm 47 and the detent 48a so that the drive pin 49 is free to reciprocate in the elongated slot 48.

As illustrated in FIG. 2, in addition to extending into the elongated slot 48 of the drive link 47 of the carbon ribbon vibrator assembly 44, the drive pin 49 also extends laterally from the extension Ila of the U-bar 11 into an elongated slot 48(/) formed in the forward portion of a drive link 470) of a fabric ribbon vibrator drive assembly (the remaining portion of which is not shown). An enlarged end portion 55am on an arm 55(/) ofa bellcrank (not shown) underlies a laterally bent out ear 560) on the bottom of the forward end of the drive arm 47()) to raise and lower the slot 48(1) in relation to the drive pin 49 in order that the drive pin 49 is selectively free to reciprocate in the slot 48(f). A complete description of the operation of the ribbon control selector mechanism and the fabric ribbon vibrator drive assembly is set forth in the hereinabove-mentioned concurrently filed copending patent application of Ronald H. McLean.

During counterclockwise motion of the U-bar 11, the drive arm 47 is adapted to move forward (as shown by an arrow labeled A in FIG. 2) under the action of the drive pin 49 and return under the action of the spring 50 when the U-bar 11 returns to its normal position thereby driving a toggle assembly, generally designated by reference numeral 57, mounted on the drive link to rock the vibrator elevating rod 43 supporting the carbon ribbon vibrator 13.

The toggle assembly 57 of the carbon ribbon vibrator drive assembly 44 shown in FIG. 2, and as more clearly illustrated in FIG. 4, comprises two

links

58 and 59 pivotally jointed together by a stud 60 fixed to the drive link 47. The other end of the toggle link 59 is pivotally carried on a bistable shifting plate or support 62 by a pivot stud 61 for giving the lower end ofthe link 59 of the toggle assembly 57 one or another support location. The other end of toggle link 58, is pivotally connected to a ribbon lift crank in the form on an arm 63 fixed to and extending outwardly from the vibrator elevating rod 43.

As best viewed in FIG. 5, the shifting plate or support 62 is pivotally mounted on a stud 66 on a frame bracket 64 mounted on a typewriter frame member 65. The shifting support plate 62 is adapted to shift the end of the toggle link 59 pivoted on the pivot stud 61 back and forth between an upper limit stop 67 and a lower limit stop 68, both of which limit stop RIBBON-LIFTING MECHANISM FOR A TYPEWRITER BACKGROUND OF THE INVENTION This invention relates to a typewriter having the capability of switching between a fabric ribbon operational mode, a carbon ribbon operational mode and a stencil operational mode, and more particularly, to an improved carbon ribbon lift mechanism embodied therein.

While the quality of the copy produced by carbon ribbon is often preferred over fabric ribbon, one of the disadvantages inherent in the use of carbon ribbon in a typewriter has been its high rate of consumption and the resultant inconvenience occasioned by the frequent need to replenish the carbon ribbon supply.

As disclosed in Page U.S. Pat. No. 3,349,888, the consumption of carbon ribbon and the frequency of replenishing the supply of carbon ribbon in a typewriter may be materially reduced by using half inch carbon ribbon, slightly larger than conventional /l6-inch carbon ribbon, and having the type contact the /2-inch carbon ribbon in a zigzag" pattern. The zigzag pattern is attained by employing a vibrator mechanism in which the vibrator lifting the ribbon is alternately driven through full and partial strokes. On the full stroke the ribbon is raised to a maximum elevation so that the type strikes the lower half of the carbon ribbon, while on the partial stroke the ribbon is positioned so that the type strikes the upper half of the carbon ribbon. After each imprint, while the escapement mechanism of the machine advances the carriage so that the succeeding imprint is properly spaced from the preceding one, the ribbon feed mechanism advances the carriage so that the succeeding imprint is properly spaced from the preceding one, the ribbon feed mechanism advances the ribbon only one-half of a normal escapement space, resulting in a staggered letter character relation on the ribbon. Thus, with a carbon ribbon only slightly wider than a conventional ribbon, the printing capacity and the lift of a spool of carbon ribbon is substantially doubled. Since the cost of /2-inch ribbon is substantially the same as the cost of 5/l6-inch ribbon, the economy and convenience attained by this method of printing is apparent.

While the ribbon-lifting mechanism in the hereinabovementioned Page patent for driving a vibrator alternately through full and partial strokes functions very satisfactorily in a matrix-type machine, it is not readily adaptable for use in a type bar machine or in a typewriter possessing the capability of selectively switching between a carbon ribbon mode and a fabric ribbon mode by the mere turning ofa selector dial.

SUMMARY In accordance with the present invention a selectively operable carbon ribbon vibrator assembly is provided in an electric typewriter. The carbon ribbon vibrator assembly includes a vibrator supporting a carbon ribbon and a toggle mechanism connected thereto pivotally mounted on a drive arm. The toggle mechanism is fulcrumed on a bistable shiftable support and operable on each forward stroke of the drive arm to open or straighten and on each rearward stroke of the drive arm to close or break about its fulcrum. A bistable trip lever also pivotally mounted on the drive arm is conditioned on each forward stroke of the drive arm to shift the position of the fulcrum support on each rearward stroke of the drive arm whereby the carbon ribbon is elevated alternately through full and partial strokes on succeeding forward strokes of the drive arm.

It is a principal object of the present invention to provide an improved ribbon-lifting mechanism for effecting movement necessary to drive a vibrator alternately through full and partial strokes.

Another object of the present invention is to provide an im proved ribbon-lifting mechanism for use on a typewriter ofthe type bar type.

Still another object of the present invention is to provide a ribbon-lifting mechanism incorporating a positively driven toggle action for driving a carbon ribbon vibrator alternately through full and partial strokes.

Other objects and advantages of the present invention will be apparent from the following description, as illustrated in the accompanying drawing, which discloses by way of example the principles of the invention and a preferred embodiment thereof.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. I is a perspective view of a portion of an electric typewriter employing twin vibrators.

FIG. 2 is a perspective view of a carbon ribbon vibrator elevating assembly in accordance with the present invention.

FIG. 3 is a perspective view of a manually controlled ribbon selector dial for coupling and uncoupling drive to the carbon ribbon vibrator elevating assembly illustrated in FIG. 2.

FIG. 4, like FIG. 2 is a view showing the carbon ribbon vibrator elevating toggle assembly in a rest position with its fulcrum in its lowermost position and conditioned to elevate and position the upper half ofa carbon ribbon shown in FIG. 1 opposite a printing point.

FIG. 5 is a view showing the drive arm in forward motion and the carbon ribbon vibrator elevating toggle assembly straightening or opening about its fulcrum positioned in its lowermost position and a trip lever positioned to be conditioned to shift the fulcrum support to position the toggle assembly to its uppermost position during the rearward movement of the drive arm.

FIG. 6 is a view showing the drive arm at the end of the forward drive started in FIG. 5, with the fulcrum of the carbon ribbon vibrator elevating toggle assembly in its lowermost position locating the upper half of the carbon ribbon viewed in FIG. 1 opposite the printing point, and the trip lever conditioned to shift the bistable support and position the fulcrum of the toggle assembly to its uppermost position on the next rearward stroke.

FIG. 7 is a view showing the drive arm in rearward motion and the carbon ribbon vibrator elevating toggle assembly being broken with its fulcrum still in its lowermost position and the trip lever commencing shifting of the bistable support to position the fulcrum of the toggle assembly to its uppermost position.

FIG. 8 is a view showing the drive arm in a rest position at the end of the rearward motion started in FIG. 7, with the bistable support shifted and the fulcrum of the toggle assembly in its uppermost position whereby the toggle assembly is conditioned to elevate and position the lower half of the carbon ribbon shown in FIG. I opposite the printing point.

FIG. 9 is a view showing the drive arm being driven forward from the FIG. 8 position and the toggle assembly straightening or opening about its fulcrum which is still positioned in its uppermost position, and the trip lever positioned to be conditioned to shift the fulcrum to its lowermost position on the next rearward stroke.

FIG. 10 is a view showing the drive arm at the end of the forward drive started in FIG. 9, with the fulcrum of the toggle assembly in its uppermost position locating the lower half of the carbon ribbon viewed in FIG. 1 opposite the printing point, and the trip lever conditioned to shift the bistable support and position the fulcrum of the toggle assembly to its lowermost position on the next rearward stroke.

FIG. I1 is a view showing the drive arm being driven rearwardly from the FIG. 10 position and the toggle assembly being broken with its fulcrum still in its uppermost position and the trip lever commencing shifting of the bistable support to position the fulcrum of the toggle assembly to its lowermost position at the end of the rearward stroke (FIG. 4).

extend outwardly from the frame carried bracket 64. An overcenter spring 69 mounted between the shifting support 62 and the frame bracket 64 alternately biases the shifting support plate 62 into contact with either the upper limit stop 67 of the lower limit stop 68. With the end of the toggle link 59 is pivoted on stud 61 and the shifting plate 62 in contact with the upper limit stop 67, the pivot stud 61 of the toggle assembly 57 is located in its uppermost position and whereby then the toggle assembly 57 is conditioned to elevate and position the lower half of the carbon ribbon CR shown in FIG. 1 opposite the printing point of the type bar' 28 during the forward stroke of the drive link 47. With the shifting plate 62 stud 61 in contact with the lower limit stop 68, the pivot stud 61 of the toggle assembly 57 is in its lowermost position whereby during the toggle straightening stroke of the drive link 47 the toggle assembly 57 will elevate and position the upper half of the carbon ribbon CR shown in FIG. 1 opposite the printing point of the type bar 28. The opposite shifting of the end of the toggle link 59 pivoted on the stud 61 between the upper limit stop 67 and the lower limit stop 68 commences as a result of movement applied to the ends of forwardly extending upper and

lower arms

70 and 71 respectively of the shifting plate 62 overcoming the bias of the overcenter spring 69.

A generally T-shaped trip lever 72 (as seen in FIG. 4) pivotally mounted at its approximate midpoint on a stud 73 provided on the drive link 47, has a pair of

arms

74 and 75 with individual bent-out

ears projections

76 and 77 at their respective ends, adapted to apply the necessary force to the end of arm 70 or to the end of arm 71 of the bistable shifting support 62 to overcome the prevalent bias of the overcenter spring 69 during the rearward stroke of the drive link 47.

An ear 78, bent out from the drive link 47, is received in an arcuate cutout portion 79 in the trip lever 72 between

arms

74 and 75. The arcuate cutout portion 79 has an upper and a lower shoulder identified by numerals 80 and 8I. The trip lever 72 is provided with a central leg 82 having an overcenter spring 83 mounted between it and the drive link 47 to alternately bias either of the

shoulders

80 and 81 into abutment with the ear 78. Movement of the

shoulders

80 and 81 relative to the ear 78 occurs as a result of the force of contact between the trip lever ear 77 and a projection 84 extending upwardly from the end ofa lower forwardly extending arm of the frame bracket 64, or as a result of the force of contact between the trip lever car 76 and a projection 85 extending downwardly from the end of an upper forwardly extending arm of the frame bracket 64, when the trip lever 72 through the stud 73 is carried forward by the drive link 47 as the latter is being actuated.

The correct path of the drive link 47 is assured by a stud stationary 80 on to the frame bracket member 64 which extends into a bifurcated slot 87 formed in the rear end portion of the drive link 47. Thereby it is assured that the connection of the drive link 47 by its notch 48a with the stud 49 in the bail arm Ila does not accidentally become disrupted. Rearward, restoring movement of the drive link 47 is limited by a stop 88 formed on the frame bracket 64.

In operation when the ribbon selector control wheel 45 is set to a carbon ribbon operational mode of operation as illustrated in FIG. 3, and the carbon ribbon vibrator elevating toggle assembly 57 is in the rest position wherein its pivot stud 61 is in its lowermost position as illustrated in FIGS. 2 and 4, the carbon ribbon vibrator elevating toggle assembly 57 is conditioned to elevate and position the upper half of the carbon ribbon CR shown in FIG. 1 opposite the printing point ofthe type bar 28 incident to the next type action.

When such next type action occurs, and the U-bar 11 and its upwardly extending arm Ila pivot counterclockwise about the cross-shaft, the drive link 47 moves forward.

As illustrated in FIG. 5, as the drive link 47 moves forward in the direction of arrow A, from the position in FIG. 4 where it abuts the stop 88, the bent out ear 77 extending from the arm 75 of the trip lever 72 strikes the projection 84 extending upwardly from the end of the lower forwardly extending arm of the frame bracket 64, to pivot the trip lever 72 counterclockwise until the biasing action of the overcenter spring 83 takes over to complete the started movement so that thus the lower shoulder 81 formed by the arcuate cutout portion 79 in the trip lever 72 abuts the bent-out ear 78 on the drive link as illustrated in FIG. 6. Thus the trip lever 72 is now positioned so that subsequently during the restoration of the drive link 47 the bistable shifting plate 62 is forcibly moved clockwise so that the toggle assembly 57 assumes the position seen in FIG.

As the drive link 47 arrives at its forwardmost position shown in FIG. 6 with the lower end of the toggle link 59 residing (in its lowermost position) in contact with the lower limit stop 68, the toggle assembly 57 is straightened is pivoting the arm 63 and the vibrator-elevating rod 43 clockwise and thus is raising the carbon ribbon vibrator 13 through a partial stroke so as to position the upper half of the carbon ribbon shown in FIG. 1 opposite the printing point of the type bar 28.

After reaching the forwardmost position shown in FIG. 6, the drive link 47 restores to the rear by the spring 50, causing the toggle assembly 57 to break or to the condition seen in FIG. 8 causing the return of the vibrator-elevating rod 43 and the vibrator 13 to their normal positions.

As viewed in FIG. 7 as the link is restoring to the rear from the FIG. 6 to the FIG. 8 position, as shown by arrow B, and since the trip lever 72 is conditioned to shift the fulcrum 61 of the toggle assembly 57 to its uppermost position, (the lower shoulder 81 of the arcuate cut out portion 79 of the trip lever 72 being in abutment with the ear 78), the ear 76 extending from the arm 74 of the T-shaped trip lever 72 strikes the end of arm 70 of the bistable shifting support 62, causing the shifting plate 62 to pivot clockwise about stud 66 until the biasing action of the overcenter spring 69 takes over and moves the shifting support 62 so that the toggle stud 61 moves to its upper position in contact with the upper limit stop 67 as shown in FIG. 8, thus conditioning the toggle assembly 57 to have capacity to elevate and position the lower half of the carbon ribbon shown in FIG. I opposite the printing point of the type bar 28, in response to the next type action.

With the next type action operation, the drive link 47 is actuated forward in the direction of arrow A as shown in FIG. 9 from the rearwardmost position illustrated in FIG. 8, in response to the action of the U-bar ll pivoting counterclockwise about cross shaft 14. During this forward movement of the drive link 47, the ear 76 extending from the arm 74 of the trip lever 72 strikes the projection 85 extending downwardly from the end of the upper forwardly extending arm of the frame bracket member 64, pivoting the trip lever 72 clockwise until the biasing action of the overcenter spring 83 takes over so that the upper shoulder of the arcuate cutout portion 79 in the trip lever 72 moves into abutment with the bent-out stop ear 78 on the drive arm as illustrated in FIG. 10, thus conditioning the trip lever 72 to shift the fulcrum support 62 to position the toggle assembly 57 in its lowermost position on the next actuating movement of the drive link.

As the drive link 47 becomes actuated to its forwardmost position shown in FIG. I0, with the toggle link 59 anchored on pivot stud 61 (in its uppermost position) in contact with the upper limit stop 67, the toggle assembly 57 straightens about its joint 60 pivoting the arm 63 and the vibrator elevating rod 43 clockwise through a greater distance than before, thereby raising the vibrator 13 through a full stroke so as to position the lower half of the carbon ribbon shown in FIG. 1 opposite the printing point of the type bar 28.

After reaching the forward position shown in FIG. 10, the drive link 47 is restored again to the rear (in the direction of arrow B) by the spring 50, causing the toggle assembly 57 to fold about its joint 60 and return the vibrator-elevating rod 43 and the vibrator 13 to their normal positions.

As viewed in FIG. II, the link 47 is being restored rearwardly since the trip lever 72 during the actuation of the link 47 was conditioned to shift the shift plate and 62 to position the toggle assembly 57 to its lowermost position (the shoulder 80 of the arcuate cutout portion 79 of the trip lever 72 being in abutment with the car 78), the ear 77 extending from the arm 75 of the trip lever 72 strikes the end of the arm 71 of the shifting plate 62, causing the shifting plate 62 to pivot counterclockwise about stud 66 until the biasing action of the overcenter spring 69 takes over and moves the shifting plate 62 and the toggle link 59 anchored on pivot stud 61 to its lower most position in contact with the lower limit stop 68, returning the parts to the positions shown in FIG. 4 thus conditioning the toggle assembly 57 to elevate and position the upper half of the carbon ribbon CR shown in FIG. I opposite the printing point of type bar 28 in response to the next type action. The above describes the sequence for two type action operations whereby the carbon ribbon is elevated alternately to low and high positions and in conjunction with effecting a half letter space ribbon feed, whereby the type impressions on the ribbon define a zigzag pattern and utilize the optimum ribbon area.

lclaim:

l. A ribbon-lifting mechanism comprising,

a frame,

vibrator-elevating means pivotally supported on said frame,

a ribbon vibrator mounted on said vibrator-elevating means,

a toggle mechanism including a first link having a first end pivotally joined to said vibrator-elevating means and a second link having a first end pivotally connected to a second end of said first link and forming therewith a toggle linkage,

bistably shiftable support means,

means on said bistably positionable support means carrying said second link pivotally at a second end thereof,

drive means connected to said toggle joint, operative in an actuating stoke to straighten the toggle mechanism and operative in a return stroke to fold said toggle mechanism,

automatic means operable in response to each return stroke of said drive means to shift the position of said bistably shiftable support means, whereby said ribbon vibrator is elevated alternately to one another positions incidental to alternate actuating strokes of said drive means,

said bistably shiftable support means including a pivotally mounted shifting plate movable in one direction from one position to a second position and movable in a counterdirection from said second position to said first position,

bias means connected to said shifting plate for alternately biasingsaid shifting plate to each of said positions after a partial movement thereto,

said automatic means including a two-armed, pivotally mounted bistable trip lever on said drive means, said trip lever in one bistable position on said drive means being capable in return stroke of said drive means to engage one portion of said pivotally mounted shifting plate to move it pivotally from said first to said second position and being capable in another bistable position to engage another portion of said shifting plate to move it pivotally from said second to said first position,

means cooperative between said drive means and said bistable trip lever to provide limits of pivotal movements for said trip lever,

an overcenter spring oppositely connected to said trip lever and said drive means for biasing said trip lever bistably to each of said pivotal limits after partial movements thereto,

a frame-supported projection in the path of one of said arms of said trip lever effective in successive alternate actuating strokes of said drive means to position said trip lever in one of its bistable positions,

and a frame-supported other projection in the path of the other of said arms of said trip lever effective in the other actuating strokes of said drive means to position said trip lever in its other bistable position.

2. In a machine having a selective typing mechanism operable to effect character imprints at a typing line,

a ribbon vibrator for projecting a ribbon from a retired position to either one of two positions over a printing line,

an element connected with said vibrator to operate it,

a mechanism responsive to the selective operation and restoration of said typing mechanism to effect respectively an operating and restoring movement of said element and connected vibrator and comprising,

a normally folded toggle linkage having a first link and a second link,

a pivotal joint between said links,

a pivotal joint connecting said element with said first link at a location spaced from the pivotal joint which connects it with said second link, 4

a means bistably positionable in one or another position for pivotally supporting said second toggle link in one or another basic pivot location at the link end thereof which is opposite to where it has a pivotal joint with said first toggle link,

and means respectively responsive to each selective operation of said typing mechanism followed by a restoration thereof, to impart respectively a straightening movement and a folding movement to said toggle,

and means operatively associated with said responsive means to effect in connection with each consecutive toggle-folding movement a movement of said bistably positionable supporting means from the bistable position it has occupied to its other bistable position,

said responsive means including a drive link to impart to said toggle linkage in conjunction with each selective operation and restoration of the typing mechanism a toggle straightening stroke followed reversely by a togglefolding stroke,

said responsive means including means conditionable in response to each toggle-straightening stroke of said drive link, so that said bistably positionable means in dependency of its then prevalent bistable position will in the following toggle-folding stroke of said drive link become operated to the other bistable position.

3. The invention defined in claim 2,

said drive link being pivotally jointed with said toggle linkage so that said drive link in its toggle-straightening stroke moves in the direction of the straightening action of the toggle linkage to either one of two positions dependent on the prevalent basic pivot location said bistably positionable means then affords to the second toggle link,

and a trip means carried on said drive'link and controllable thereby during the conclusion of its toggle-straightening stroke, due to the position to which said drive link moves in the direction of the straightening action of the toggle linkage, to become potent in the toggle-folding return stroke of said drive link to act on said bistably positionable means to reverse its bistable position.

4. The invention defined in claim 3,

two frame-supported abutments,

said trip means being a two-armed bistable member pivotally carried on said drive link, and the arms of said two-armed member during alternate toggle straightening strokes of said drive link being adapted to engage alternately one or the other of said abutments to cause opposite rocking movements of said two-armed bistable member, said two-armed bistable member, due to being alternately rocked in the toggle straightening strokes of said drive link, being effective in the toggle folding return strokes to act on said bistably positionable means to reverse its bistable position.

5. In a machine having a selective typing mechanism operable to effect character imprints at a typing line,

an element connected with said vibrator to operate it,

a mechanism responsive to the selective operation and restoration of said typing mechanism to effect respectively an operating and a restoring movement of said element and connected vibrator and comprising,

a normally folded toggle linkage having a first link and a second link,

a pivotal joint between said links,

a pivotal joint connecting said element with said first link at a location spaced from the pivotal joint which connects it with said second link,

and means respectively responsive to each selective operation and restoration of said typing mechanism, to impart to said toggle respectively a straightening movement and a folding movement,

and means opcratively associated with said responsive means to effect in consequence of each consecutive toggle folding movement following a toggle straightening movement, a movement of said bistably positionable supporting means from the particular bistable position it has occupied to the other one of its bistable position.

6. The invention defined in claim 5,

said responsive means effecting during the restoration of said typing mechanism each time a forced partial movement of said bistably positionably means from whichever of said two positions it has occupied toward the other position,

and spring means cooperative with said bistably positionable means to complete each ofits said started movements.

Claims

1. A ribbon-lifting mechanism comprising, a frame, vibrator-elevating means pivotally supported on said frame, a ribbon vibrator mounted on said vibrator-eleVating means, a toggle mechanism including a first link having a first end pivotally joined to said vibrator-elevating means and a second link having a first end pivotally connected to a second end of said first link and forming therewith a toggle linkage, bistably shiftable support means, means on said bistably positionable support means carrying said second link pivotally at a second end thereof, drive means connected to said toggle joint, operative in an actuating stroke to straighten the toggle mechanism and operative in a return stroke to fold said toggle mechanism, automatic means operable in response to each return stroke of said drive means to shift the position of said bistably shiftable support means, whereby said ribbon vibrator is elevated alternately to one and another positions incidental to alternate actuating strokes of said drive means, said bistably shiftable support means including a pivotally mounted shifting plate movable in one direction from one position to a second position and movable in a counterdirection from said second position to said first position, bias means connected to said shifting plate for alternately biasing said shifting plate to each of said positions after a partial movement thereto, said automatic means including a two-armed, pivotally mounted bistable trip lever on said drive means, said trip lever in one bistable position on said drive means being capable in return stroke of said drive means to engage one portion of said pivotally mounted shifting plate to move it pivotally from said first to said second position and being capable in another bistable position to engage another portion of said shifting plate to move it pivotally from said second to said first position, means cooperative between said drive means and said bistable trip lever to provide limits of pivotal movements for said trip lever, an overcenter spring oppositely connected to said trip lever and said drive means for biasing said trip lever bistably to each of said pivotal limits after partial movements thereto, a frame-supported projection in the path of one of said arms of said trip lever effective in successive alternate actuating strokes of said drive means to position said trip lever in one of its bistable positions, and a frame-supported other projection in the path of the other of said arms of said trip lever effective in the other actuating strokes of said drive means to position said trip lever in its other bistable position.

2. In a machine having a selective typing mechanism operable to effect character imprints at a typing line, a ribbon vibrator for projecting a ribbon from a retired position to either one of two positions over a printing line, an element connected with said vibrator to operate it, a mechanism responsive to the selective operation and restoration of said typing mechanism to effect respectively an operating and a restoring movement of said element and connected vibrator and comprising, a normally folded toggle linkage having a first link and a second link, a pivotal joint between said links, a pivotal joint connecting said element with said first link at a location spaced from the pivotal joint which connects it with said second link, a means bistably positionable in one or another position for pivotally supporting said second toggle link in one or another basic pivot location at the link end thereof which is opposite to where it has a pivotal joint with said first toggle link, and means respectively responsive to each selective operation of said typing mechanism followed by a restoration thereof, to impart respectively a straightening movement and a folding movement to said toggle, and means operatively associated with said responsive means to effect in connection with each consecutive toggle-folding movement a movement of said bistably positionable supporting means from the bistable position it has occupied to its other bistable Position, said responsive means including a drive link to impart to said toggle linkage in conjunction with each selective operation and restoration of the typing mechanism a toggle straightening stroke followed reversely by a toggle-folding stroke, said responsive means including means conditionable in response to each toggle-straightening stroke of said drive link, so that said bistably positionable means in dependency of its then prevalent bistable position will in the following toggle-folding stroke of said drive link become operated to the other bistable position.

3. The invention defined in claim 2, said drive link being pivotally jointed with said toggle linkage so that said drive link in its toggle-straightening stroke moves in the direction of the straightening action of the toggle linkage to either one of two positions dependent on the prevalent basic pivot location said bistably positionable means then affords to the second toggle link, and a trip means carried on said drive link and controllable thereby during the conclusion of its toggle-straightening stroke, due to the position to which said drive link moves in the direction of the straightening action of the toggle linkage, to become potent in the toggle-folding return stroke of said drive link to act on said bistably positionable means to reverse its bistable position.

4. The invention defined in claim 3, two frame-supported abutments, said trip means being a two-armed bistable member pivotally carried on said drive link, and the arms of said two-armed member during alternate toggle straightening strokes of said drive link being adapted to engage alternately one or the other of said abutments to cause opposite rocking movements of said two-armed bistable member, said two-armed bistable member, due to being alternately rocked in the toggle straightening strokes of said drive link, being effective in the toggle folding return strokes to act on said bistably positionable means to reverse its bistable position.

5. In a machine having a selective typing mechanism operable to effect character imprints at a typing line, a ribbon vibrator for projecting a ribbon from a retired position to either one of two positions over a printing line, an element connected with said vibrator to operate it, a mechanism responsive to the selective operation and restoration of said typing mechanism to effect respectively an operating and a restoring movement of said element and connected vibrator and comprising, a normally folded toggle linkage having a first link and a second link, a pivotal joint between said links, a pivotal joint connecting said element with said first link at a location spaced from the pivotal joint which connects it with said second link, a means bistably positionable in one or another position for pivotally supporting said second toggle link in one or another basic pivot location at the link end thereof which is opposite to where it has a pivotal joint with said first toggle link, and means respectively responsive to each selective operation and restoration of said typing mechanism, to impart to said toggle respectively a straightening movement and a folding movement, and means operatively associated with said responsive means to effect in consequence of each consecutive toggle folding movement following a toggle straightening movement, a movement of said bistably positionable supporting means from the particular bistable position it has occupied to the other one of its bistable position.

6. The invention defined in claim 5, said responsive means effecting during the restoration of said typing mechanism each time a forced partial movement of said bistably positionable means from whichever of said two positions it has occupied toward the other position, and spring means cooperative with said bistably positionable means to complete each of its said started movements.