US2734614A

US2734614A - Proportional ribbon feed mechanism

Info

Publication number: US2734614A
Authority: US
Publication date: 1956-02-14
Anticipated expiration: 1973-02-14

Description

Feb. 14, 1956 R. E. PAGE PROPORTIONAL RIBBON FEED MECHANISM 's Sheets-Sheet 1 med June 18,,1952

INVENTOR Feb. 14. 1956 R. E. PAGE 'PROPORTIONAL RIBBON FEED MECHANISM Filed June 18, 1952 5 Sheets-Sheet '2 INVENTOR RAL PH E. PAGE R. E. PAGE 2,734,614

PROPORTIONAL RIBBON FEED MECHANISM Feb. 14. 1956 Filed June 18 1952 3 Sheets-Sheet 3 FIG. 3

INVENTOR RALPH E. PAGE ew am AGENT United States Patent PROPORTIONAL RIBBON FEED MECHANISM Ralph E. Page, Lagrangeville, N. Y., assignor to International Business Machines Corporation, New York,

N. Y., a corporation of New York Application June 18, 1952, Serial No. 294,160 13 Claims. (Cl. 197-151) This invention relates to machines for producing printed characters of different dimensionsan'd more particularly to typewriting machines in which "the characters are of a number of different widths.

It has been the practice in typewriting and like machines to advance a printing ribbon a uniform amount past the striking point each time a type bar is operated. This advancement took place immediately after a character was printed and in such an amount as to accommodate the width of the widest character "(usually a capital M or W) in the font of type being employed. These wide characters are seldom used when compared with the relatively narrow lower case letters such as a, e, i, and and with the narrow punctuation marks; and for this reason a considerable amount of wastage occurred in the use of ribbons, such as carbon ribbons, which are passed through the machine only once. Since carbon ribbons are a relatively expensive product, it is expedient that the unused area of a spent carbon ribbon be reduced to a minimum.

Accordingly, it is an object of this invention to produce a typewriter or like machine which makes the maximum use of the available area of a printing ribbon.

A more specific object of the invention is to provide a typewriter or like machine having a mechanism which advances the ribbon in proportion to the width of the character printed.

Another object of the invention is to provide a simple and compact variable ribbon advancing mechanism for typewriter or like machines that isaccurate and reliable in operation.

Yet another object of the invention is to provide a variable ribbon advancing mechanism which takes up little of the crowdedspace in a typewriting machine.

A further object of the invention is to .provide a variable ribbon advancing mechanism that utilizes as far as possible the existing elements of a typewriter or like machine and one which offers the least interference with thelocation and operation of other'mechanisms in the machine.

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

In the drawings:

Fig. l is a vertical section through a portion of a typewriting machine-in which the expressed invention has been embodied.

Fig. 2 is another vertical section through the typewriting machine showing the variable ribbon advancing mechamsm.

Fig. 3 is a plan view of theapparatus shown in Fig. 2.

Fig. 4 is an enlarged view of a portion of the apparatus shown in Fig. 3. v

The invention is disclosed in the drawings as applied to a well known form of an electrically driven power operated typewriting machine known commercially as the IBM Electric Executive. The IBM Electric Executive typewriting machine is provided with mechanisms for advancing the platen supporting carriage in a letter spacing direction in proportion to the width of the character printed, which mechanism are disclosed in the U. S. Patent No. 2,547 449,'issue d April 3, 1951, to R. D. Dodge. It will be understood, however, that the inven- 'in the side plates 1 of the machine.

2,734,614 Patented Feb. 14, 1956 tion may be applied to other forms of power operated typewriters and even to manually operated typewriters.

The typewriter shown is provided with side plates 1 constituting part ofla rigid machine framework, a pair of grooved front and rear carriage rails '2 and 3, a carriage 4 having a rotatable work platen 5 and suitably biased for movement in a letter spacing direction, and truck roller assemblies -6 for movably supporting a grooved channel spaced member 7 of the carriage on the rails 2 and 3. The typewriter also includes in addition to a power roller 10 continuously rotatable by a suitable electric motor (not shown), a key actuated type bar operating mechanism 12, a space selecting mechanism 14, and a variable escapement'mechanism 16 for the carriage. The cscapcment mechanism is operatively connected with'the type bar operating mechanism to release the carriage '4 for a movement proportional to the minimum character width (usually two units) each time a type bar operating mechanism is actuated. However, whenever a'type bar having a character of one of the three consecutive large widths (usually three, four and five units) in a font of type is struck, the space selecting mechanism operatively connected with each of the operating mechanism for the type bars bearings characters of the larger width, actuates the escapement mechanism to release the carriage ice "for additional movement proportional to the added width of the character.

'The numeral 18 designates one of the key levers of which there is-one for each set of characters. Each key lever 18 is pivoted on a cross rod 20 suitably supported Each key lever 18 is provided with a finger'button 24 and a restoring spring 26 which urges the key lever '18 in a counterclockwise direction (Fig. 1). The forward or right-hand ends of the key levers are guided in slots 28 in a key guide bail 30 which is also suitably mounted on the side plates 1.

A character printing type bar 32 is provided for each key lever 18. Each type bar, as is usual in the art, may be provided with two types 34 constituting a set of characters comprising respectively upper and lower case characters. The type bars 32 are supported in a type 'basket '36 which includes the usual segment 38 and the type bars are pivoted-in the segment by the usual curved 'pivot' wire-40. The segment 38 is slotted to accommodate the-type bars and, since thesegment is curved, the type bars recline on the type'rest 42 of the type basket at the angle shown in Fig. '1, but at different levels in the machine.

Each type bar 32 is moved by a corresponding type bar operating mechanism '12. Each type bar operating mechanism '12 includes a sub-leverv 44 connected by a link 46 to an extension'SZizformed in the associated'type bar 32. ;It will be evident that rocking of a sub-lever 44 clockwise, acts through a link. 46 to rotate the corresponding type bar 32 in a counterclockwise direction'to engage one or the other of-the type characters34 with a worksheet on the platen 5, the type striking through the usual ribbon. At theprinting point the'types are guided by a type guide 48 which is secured to thefrontface of the segment 38. The type guide 48 slidably supports a ribbon vibrator 5,0 which is mounted on the'upper end of a link 52pivoted at 'its'lower end to a lever 54. A suitable means (not shown) is used for actuating the ribbon lever 54.

The lower end of ,eachsub-lever 44 is formed with a deep notch at 44a which cooperates with a fulcrum strip 56 having a rounded nose 56a. The nose 56a is kept seated in the notch 44a by means of a spring 58 anchored to'the lowerend of 'the'sub-lever 44 below the notch and to a lug 56b formed on thefulcrum strip 56. The spring 58 not'only serves to'hold'the sub-lever 44 on the pivot or nose 4412, but also tends to restorethe sub-leverwhen it has been actuated as hereafter described and, in- I cidentally, assists in restoring the type bar 32 after it has made its impression.

Each type bar operating mechanism also includes a somewhat L-shaped cam element 60 pivoted at 62 on the sub-lever 44. This cam element 60 is provided with a restoring spring 64 which is anchored to an ear 60a formed on the cam element and to a lug 44b struck from the sublever 44. The cam element 60 is provided with a spiral tread at 6012 designed to cooperate with the power roller which rotates continually in the direction of the arrow (Fig. 1) while the machine is in use. Normally, however, the upper end of the tread clears the power roller with the parts in the position shown which is the normal position.

Each cam element 60 has an elongated tail piece 660 which ordinarily is held in engagement with a lug 66a on a release member or interposer 66 by the spring 64. The release member 66 is provided with a slot 66b through which passes a stud 68 carried by an arm 44c forming part of the sub-lever 44. A spring 70, connected to an ear 66c formed in the release member 66 just below and to the right of the stud 68 and to a lug 44d formed in the arm 44a of sub-lever 44, holds the release member 66 with the stud 68 at the right-hand end of the slot 66b and also normally holds member 66 with its extension 66d up against the lug 44d. The member 66 has a lug 66c which lies in the path of a short extension or lug 18a on the character key lever 18.

When the character key lever 18 is depressed, the member 66 will be rocked slightly counterclockwise by the engagement of the lug 18a with the lug 66a. This rocks the cam 66) slightly clockwise sufficiently to bring the upper end of the tread 60b into engagement with the surface of thepower roller 10. Thereafter, the power roller 10 drives the cam 60 in a clockwise direction and, due to the eccentric shape of the tread 60b with respect to the cam member pivot 62, pushes the stud 62 to the right in a short arcuate path, thereby swinging the sub-lever 44 in a clockwise direction on pivot 56a and, through the link 46, operating the type bar 32 to effect an imprint from one of the types 34.

The variable escapement mechanism, operative to release the biased carriage in a letter spacing direction each time a type bar is actuated for a limited movement proportional to the width of the character printed, comprises a series of biased pawls 72 mounted in a block 74 on the rear carriage rail 3 of the typewriter so as to engage an escapement rack 76 carried by the carriage 4 on the bottom of the channel-shaped member 7. The pawls 72 are disposed transversely of the machine (that is,

parallel to the escapement rack) and are slidably and pivotally mounted on a vertically extending stud by means of slots having an effective length equal to the pitch of the rack. The pawls 72 differ from each other in length by one unit of spacing and the slots are spaced the same distance from the toothed end of each pawl. It results that the toothed end of the pawls will engage one or both of two adjacent teeth on the escapement rack when the latter is being held stationary and that the free or other ends of the pawls will be spaced from each other by one unit of spacing.

The amount of movement for which the carriage is released by the escapement mechanism is dependent on the number of pawls 72 having the farthest extending ends that are swung out of engagement with the rack 76. If the pawl, whose free end extends the farthest, has its toothed end swung clear of the rack, the carriage will be permitted to undergo a movement equal to one unit of spacing. Similarly, if the pawl, whose free end is spaced one unit from the farthest extending free end also has its toothed end swung out of the rack, the carriage will be permitted to undergo a movement equal to two units of spacing. Hence, whenever all the pawls whose free ends extend beyond a selected point are swung out of engagement with the rack, the carriage will be released V 4- to move a number of units of spacing corresponding to the number of pawls that were swung.

The swinging of the desired number of pawls is obtained through the use of a group of four flat interposers '78, each one unit of spacing in thickness and held in side by side sliding contact by a cage 80. The cage is provided with a stud 82 on which all the interposers are pivotally mounted. The three right hand interposers are mounted on the stud 82 by means of slots 73a whereby they may also be shifted vertically to dispose a portion 78b in the path of movement of a common operating member 84. The left hand interposer is not recessed at 780' as are the three right hand interposers and for this reason it will be shifted each time the operating member 84 is swung on its pivot 84a. By disposing the interposers so that the left hand interposer engages only the two pawls 72 whose free ends extend the farthest and by connecting the operating member E4 through a link 86 with a universal bar 88 disposed in the path of all of the type bars 32, provision will have been made for releasing the carriage to move the minimum two units of spacing each time a character is printed. Such a disposal of the left hand interposer locates each of the three right hand interposers so that they will engage respectively when swung the three pawls, the four pawls, and the five pawls whose free ends extend the farthest. Hence, by raising the second, third or fourth interposer from the left hand end of the group of interposers, the carriage will be released respectively-for three, four, or five space units of travel after a type bar is struck.

The raising of the three right hand interposers is elfected through the space selecting mechanism 14 which, as shown in Figs. 1 and 2, is mounted underneath the keyboard just in front, that is, to the right in Fig. 1, of the power roller 10. It includes a series of three

bail members

90A, 90B, 90C, respectively connected to the three right interposers '78, a series of bail member operating bars 92 respectively shiftable by the operating mechanism of each type bar bearing a lower or an upper case character of more than two units of width, a pair of vertically shiftable plates 94.- for supporting the bail members and efiecting operating connections between the bail members and their operating bars when an upper case letter is printed that is different from those eifected when a lower case letter is printed, and a rockable shaft 96 for locating the bail member support plates according to the case of the character being printed.

The cross shaft 96 is journalled in the side frames of the typewriter underneath the front ends of the key levers 18. Adjacent the side frames the shaft 96 is circumferentially grooved to receive and guide the vertically slotted upper ends 94a of the support plates 94 in which the ends of the three selector bails are pivotally received. To compel the support plates 94 as a whole to move vertically and linearly, any suitable additional guide means may be provided such as studs fixed to the end platesand slidably received in vertical slots in the lower ends of the support plates. Each bail depends from the support plates and consists of a bight portion extending across the key board and cranks for mounting the bight portion in offset relation upon crank pins pivoted in the end plates. Fixed to the shaft 96 near its ends to shift the plates vertically upon rotation of the shaft are parallel levers 960 each of which has a pin that is pivotally and slidably received in a horizontally extending slot 94b formed in the corresponding support plate 94.

To rock the shaft 96 another lever 96!) is fixed to it. The free end of this lever is connected by a link 93 to a lever 99 mounted on a shaft 100 that forms part of the usual shift mechanism (not shown) of the typewriter. Whenever the shift mechanism is actuated to enable the typewriter to print upper case letters, the shaft 100 is rotated clockwise to rock the shaft 96 counterclockwise and raise the support plates 94 and bails 90' vertically.

The

bail members

90A, 90B, 90C are operatively connected with respective ones of the three right hand interposers 78 through similar sets of arms 101, links 102, and bell cranks 103. The arms 101 are pivotally mounted at their upper ends on the rockable shaft 96 and are pivotally connected at their lower ends to respective ones of the links 102. The arms 101a, 1015, 101s are formed so as to lie directly behind corresponding ones of the

bail members

90A, 90B, 90C and be moved by them when they are rocked. The links 102 are connected at their rearward ends to depending arms of corresponding ones of the bell cranks 103. The other arms of the bell cranks extend horizontally rearward from the fixed bell crank pivot 103a and are bifurcated at their free ends to receive lugs formed on corresponding ones of the three right hand interposers 78. It results that rearward swinging of one of the bail members 90 rocks the corresponding arm 101 to shift a link 102, rock a bell crank 103, and raise a corresponding interposer 78 into the path of the common operating member 84. In the embodiment shown, the bail member 90A has been operatively connected with the three unit interposer, the bail member 90B with the four unit interposer, and the bail member 90C with the five unit interposer. A spring 104 and a cooperating stop member 104a engage each of the bell cranks to urge the respective arms 101 to a normal position in which they hold the bail members slightly forward of their gravitational positions.

One of the series of bars 92 is shifted to operate one of the bail members 90 whenever a character having a width of more than two units is printed. Each bar 92 extends horizontally and rearwardly from beneath the bail members and is guided for endwise movement at its front end by a slot 92a slidably received on a cross-bar 105. The rearward ends of the operating bars 92 are pivotally connected at 106 with the lower ends of the sub-levers 44 of the respective type bar operating mechanisms 12. It will be evident that the rocking movement undergone by a sub-lever 44 when a type bar operating mechanism is actuated will first act to move the corresponding operating bar 92 rearwardly from a normal position and then to restore it.

Rocking of the bail members is obtained by disposing their bight portions in the paths of lugs 108 formed on the operating bars 92. Each operating bar is provided with an individual lug for each bail member that is to be operated by it, and these lugs are disposed directly in front of the bight portion of the corresponding bail member so that when the operating bar is pulled rearward, the bail member will be swung clockwise as seen in Fig. 1. Hence by providing the operating bar with a lug in front of the bail member 90A when the corresponding type bar bears a character having a width of three units, or in front of the bail member 90B when the corresponding type bar bears a character having a width of four units, or in front of the bail member 90C when the corresponding type bar bears a character having a width of five units, the main carriage will be released for an escapement proportional to the width of the character printed.

Since an upper case letter may be of a width different from that of a lower case letter, provision is made for varying the effectiveness of lugs between the lower and raised positions of the'bail members. In the embodiment shown, this has been obtained by cutting away portions of full lugs, such as lug 1080, which is operative to rock the bail member 90C whether the typewriter is printing upper or lower case letters. Lug 108a is exemplary of a lug that is operative to shift its corresponding bail member only when a lower case letter is being printed. It is inoperative when the bail members have been raised because it lacks the top portion of a full lug. Its top surface inclines rearwardly'to guide the corresponding bail 'case letter is being printed.

member back to it's normal position when the support plates 94 are lowered. Lug 108b is typical of those which rock the corresponding bail member only when an upper It represents a full lug that has had the bottom of its rearward side cut away, leaving nothing to shift the bail member for lower case letters. It should be remembered that whenever an operating bar has a lug of the 108a or 108b type, the carriage will escape only two units in the other case, unless the other of the 108a or 108b type is provided for another bail.

In the embodiment shown, the variable ribbon advancing mechanism utilizes the space selecting mechanism 14 originally provided for the variable carriagespacing mechanism for indicating the amount. of movement that should be imparted to the ribbon after a given character of a font of type having characters of a number of different Widths is printed. The variable ribbon advancing mechanism also includes a ribbon feeding mechanism 110, a power operated mechanism 112 for automatically driving the ribbon feeding mechanism after a character has been printed, and a mechanism 114 for controlling the amount of. motion imparted by the power operated mechanism to the ribbon feeding mechanism in accordance with the indications of the space selecting mechanism.

The ribbon feeding mechanism includes a pair of contacting

rollers

116 and 118 between which the carbon ribbon is passed so that rotation of the rollers effects a drawing of the ribbon through the machine. One of the rollers 116 is fixed on a shaft 120 carried in a bearing housing 122 fixed in a plate 124' mounted in laterally spaced relation to the left side plate 1 of the machine by bracket members 126. The roller 116 is formed by covering a portion of the shaft with hard rubber and carries a gear portion 116a secured to rotate with it.

The other roller 118 is also surfaced with rubber and fixed to rotate with a gear portion 118a. Unlike roller 1 16 however, it is freely rotatable on a shaft 128 which is rigidly secured upon the free upper end of an arm 130 pivotally mounted at its lower end upon a stud 132 fixed upon the plate 124. A spring 132 anchored at one end to a lug 124a formed on the plate 124 pulls upon an extension 130a beneath the pivot point of the arm, 130 to urge the upper end of the arm so that the rubber surfaced rollers engage each other or are placed in such proximate relation with each other that they will coact upon a ribbon placed between them to grasp it, and so that the teeth of the gears mesh to transmit a rotational force applied upon one of them to the other.

The

rollers

116 and 118 are rotated through a one way clutch connection between the shaft 120 and a lever 134 rotatably mounted thereon. The lever 134 is forked at one end 134a to slidably and pivotally embrace a bushing 136 to which it is rigidly but adjustably secured by a fastening 138 extending through a slot formed in it to engage an apertured lug 136a formed on the bushing 136. The bushing 136 is rotatably mounted on a reduced portion 1200 of the shaft 120 and is provided with a shoulder 136b having an outer surface flush with the outer surface of the non-reduced portion of the shaft. A coil spring 140 surrounds the shoulder 136b of the bushing and an adjacent portion of the abutting shaft to where a clip washer 142 seated in a circum ferential groove 144 formed in the shaft 120 locates the shaft 120 with respect to the fixed sleeve 122. The internal diameter of spring 140 is such that it is snugly yet frictionally mounted on the bushing and the nonreduced shaft portion. Thus when the lever 134 is swung upwards as seen in Fig. 2, the rotation of the bushing in a direction counter to the winding of the spring tightens the spring about the bushing and shaft in a well known clutching manner so that the shaft and rubber surfaced roller 116 secured upon the shaft are rotated counterclockwise, as seen in Fig. 2, in unison snags with the bushing and the lever. However, a later clockwise restoring of the lever and the bushing uncoils the spring and allows the bushing and lever to rotate freely of the shaft. The shaft 120 is kept from following the lever and the bushing during the clockwise restoring of the latter by a cambered-disk or spider friction spring 137. The friction spring is provided with a central aperture by which it is mounted on the shaft 129 in a compressed condition between an enlarged end 122:: of the fixed non-rotatable bearing housing 122 and the ad jacent end of the rubber-coated roller 116. It will be evident that the rollers will actupon the ribbon to move it in one direction only and that the amount of this movement will be proportional to the degree of restoration permitted the lever before it is swung upwards again as seen in Fig. 2.

The power operated mechanism 112 drives the ribbon feeding mechanism by rocking the lever 134 to and fro. It embodies a biased U-shaped member 144, a cam unit 146 for moving the U-shaped member 144 against its bias, and mechanism 148 for actuating the cam unit each time a type bar is struck. The U-shaped member 144 is inverted and pivotally mounted at the end of its rearward leg 144a on a stud 150 rigidly mounted on the left side plate 1 of the machine. A spring 152 pulls upon a lug 144a formed on the U-shaped member 144 to bias the member clockwise as seen in Fig. 2 and urge its forward leg 144b downward.

The cam unit 146 for moving the U-shaped member includes a suitable frame 153 pivoted on a fixed stud 154 and biased counterclockwise by a spring 155 to a normal position in which it rests on a fixed support 156, a cam 158 rotatably mounted on the frame, and a trip lever 1611 biased by a spring 161 to a normal position in which it is active to hold the cam out of contact with the power roller in a well known way. A detailed explanation of the construction and operation of such cam units may be found in the U. S. Patent No. 2,540,031, issued to W. P. Hazelton on January 30, 1951. It suffices here to point out that actuation of the trip lever releases the cam 158 into engagement with the power roller 10 which then rotates the cam and, due to the eccentricity of the cam, acts to rotate the frame in a clockwise direction about the stud 154. The spring 155 restores the frame 153 to its normal position when a recessed portion of the cam is rotated into a position opposite the power roller 10.

The cam unit moves the U-shaped member 144 through a link 162 and a bail 164. The bail 164 is an L-shaped piece rigidly mounted on a shaft 166 rotatably supported on the side plates 1 of the machine by the fixed studs 150 so that its offset portion 164a extends between the legs of the U-shaped member 144. The link 162 is pivotally connected at its respective ends to the cam unit frame member 153 and the bail 164 so that clockwise rocking of the cam unit effects a counterclockwise or upward movement of the bail member. It results that upward movement of the offset portion 164a of the bail 164 causes it to engage the lower surface 144d of the bight portion of the U-shaped member 144 and swing it counterclockwise against the bias of spring 152. By inserting a link 168 between the U-shaped member 144 and the lever 134, the power operated mechanism is operatively connected to drive the carbon ribbon feeding mechanism 110. In the event that the machine is provided with an alternately useable cloth ribbon feeding mechanism such as that disclosed in the Hazleton patent, supra, a link 170 may be provided between such a mechanism and a lug 144 formed on the U-shaped member, thereby enabling the one power operated mechanism 112 to drive both types of ribbon feeding mechanisms.

The mechanism 148 for actuating the cam unit 146 each time a type bar 32 is struck, comprises a vane 172 rockable by each of the type bar operating mechanisms 12 and a link 174 for moving the trip lever 160 of the cam unit 146 when the vane is rocked; The vane is formed with a sleeve portion 172a whereby it is rotatably mounted on the shaft 166 and from which it projects upwardly into the path of movement of lugs 176 formed on the lower end of each sub-lever 44 of the type bar operating mechanism. Hence, whenever the sub-lever is rotated clockwise to actuate a type bar 32, it also rocks the vane 172 counterclockwise. This rocking of the vane acts through a lever 178 rigidly connected to it to pull downward upon the link 174 and. actuate the trip lever 169. Spring 161 which biases the trip lever also acts through the link 174 to urge the vane to its normal clockwise position. A slot 180 formed in the trip lever permits the trip lever to move independently of the vane when the frame member is rocked clockwise by the operation of the cam.

Since the lever 134 of the ribbon feed mechanism 110 and the U-shaped member 144 of the power operated mechanism 112 are interconnected by the link 168, it will be appreciated that the clockwise position to which the U-shaped member is permitted to move under the influence of its spring 152 before the operation of the cam unit 146 determines the amount of ribbon feed effected each time a character is printed. Stated otherwise the amount of counterclockwise movement induced in the U-shaped member 144 and hence the amount of rotation applied to the

feed rollers

116 and 118 by the lever 134 will be proportional to the nearness of said surface 144d of the U-shaped member to the offset portion 164a of the bail 164 when the cam unit 146 is operated.

The motion control mechanism 114 determines the clockwise position of the U-shaped member 144 before it is acted upon by the cam unit 146. It consists of an operating bar 182 shiftable from a normal position by the space selecting mechanism 14 and a lever 184 normally disposed in the path of movement of the farthest extension of the forward leg 144b of the U-shaped member but movable thereout by the bar to where it may be engaged by a stepped portion 144e of the U-shaped member upon further clockwise movement thereof or to where it is completely out of the path of the leg 144b. The lever thus establishes respectively, the first, second and third clockwise positions to which the U-shaped member may be moved by its spring 152.

The operating bar 182 extends horizontally and rear- Wardly from beneath the bail members of the space selecting mechanism 14 and is guided for endwise movement at its front end by a slot 182a slidably received on the cross-bar and at an intermediate point by a projection 182d slidably received in a vertical slot 183a formed in a cross-bar 183. The rearward end of bar 182 is supported by and pivotally connected to the right hand end 184a of the lever 184 which rests upon the upper surface of a support bracket 186 secured to the inward surface of the left side plate 1 and is pivoted intermediate its ends upon a stud 188 extending upwardly from the upper surface of the support bracket 186. A spring 190 biases the operating bar 182 to a normal position determined by the engagement of a lug 1820 formed on the bar with the five unit bail 90C in its normal position. The operating bar 182, the lever 184, and the U-shaped member 144 are so proportioned that when the operating bar is in normal position, the left hand end 1841; of the lever 184 is disposed in the path of movement of the farthest extension of the forward leg 144b and acts to hold the U-shaped member 144 in its first position.

it will be evident that U-shaped member 144, the link 168, and the parts of the ribbon feed mechanism may be so proportioned and arranged that the counterclockwise angle through which the U-shaped member is rotated from its first position by the operation of the cam unit 146 will cause the ribbon feed mechanism to ad vance the ribbon the minimum amount desired. While this minimum amount could be made proportional to the width of the smallest character in the font of type,-namely two units, it is undesirable to do so as they are few in number and their use occurs at such widely separated intervals that very little ribbon is wasted by making I this minimum amount proportional to the three unit width of the next larger and much more predominant characters. This elimination of the two unit ribbon feeding increment simplifies the construction of the-device and thereby renders-it easier andcheaper of manufacture and more reliable in operation. These advantages more than offset the very slight waste of ribbon resulting from a ribbon advancement proportional to three units when only a two unit character is printed.

As has been pointed out "hereinbefor'e, each time a character having a width of five unitsis printed, the corresponding type bar operating mechanism 1-2 rocks the front bail 90C of the space selecting mechanism 14 rearward. Since the lug 1820 on theoperating bar 182 abuts the bail member 900 when the operating bar is in normal position under the influence of the spring 190, the operation of the bail member 90C will shift the operating bar its maximum distance rearward and rotate the lever 184 completely outof the path of the leg 144b. Hence the U-shaped member will be permitted to rotate clockwise a maximum distance to its third position in which its surface 144a rests upon the bail 164. The U-shaped member, the link 168, and the parts of'the ribbon feed mechanism are also so proportioned and arranged that the rocking of the U-shaped member through'the same counterclockwise angle that the bail 144-undergoes when "the cam unit 146 is operated causes the ribbon feed mechanism to advance the ribbon an amount proportional to the five unit width of the largest characters in the font of type.

When -a character having a 'width of four units is printed, the intermediate bail member 908 is swung rearward. A portion of this movement of 'the bailmember is utilized to shift the operating bar-182m an intermediate position in which it locates the lever 184 where "it will be engaged by the stepped portion 144e of the U-shaped member. Engagement of the stepped portion 1442 with the lever 184 establishes the U-shaped member 144 in its second position from which it willbe moved by the operation of the cam unit 146 through an arc suflicient to cause the ribbon feed mechanism to advance the ribbon an amount proportional to the width of the four unit characters. The portion of the movement of the bail member 90B necessary to shift the operating bar to its intermediate position is obtained by forming on the operating bar a lug 182b whose forward vertical edge is spaced from the bail member 9013 when the operating bar is in normal position. -Hence,'the bail member will undergo some movement before .it engages the .lug 182k and the effective portion of its movement upon 'the operating bar will be less than that of the bail member 906 with the result that the operating bar will be. moved to its intermediate position.

The lug 182i) is of reduced width and may be thought of as being a full lug such as '182c whose forward portion has been cut away. The reduced width is necessary to insure that the rearward edge of the lug does not interfere with the bail 90A when the operating bar 182 is shifted rearward.

If it is desired to further-simplify the motion control mechanism, the lug 18% may be formed of full width as indicated by the dotted line in Fig. 2 so as to abut the bail 903 when the operating bar is in normal position. With this construction, the operatingbar will rotate the lever clear of the leg 14% when a character having a width of 'four units is printed to cause the U-shaped member to operate the ribbon feed mechanism so as to advance the ribbon an amount proportional to the width of afive unit character. Such a variable .ribbon advancing mechanism would then have two unit characters is comparatively small in'proportion to the number of three and five unit characters.

On the other hand, if it is desired to advance the ribbon in proportion to the width of each character printed, the first position of the U-shaped member as determined by the normal position of the operating bar is chosen so that operation of the power unit drives the ribbon feed mechanism so as to advance the ribbon an amount proportional to the width of a two unit character. Two stepped portions are formed on the U-shaped member and these are so chosen that the ribbon will be advanced amounts proportional to the width of the three and four unit characters. An additional lug is formed on the operatlng'bar so as to be spaced a proportionately greater amount in back of the bail member A than the lug 1821) is spaced in back of the bail member 90B. Lug

1820 and hail member 90C would continue to move the lever entirely'out of the path of the forward leg.

Typewriters are often used for stencilling operations and to this end they are provided with a control for retaining the ribbon out of the path of the types 34 on the type bar. Such a control includes a shaft 192 which is rocked clockwise from its position shown in Fig. 2 to inactivate the ribbon lever 54 which actuates the ribbon vibrator 50.

Since a carbon ribbon is fed through the machine only once, it is highly desirable that the ribbon feed be discontinued during the stenciling operations. To this end, provision is made for inactivating the cam unit 146 of the variable ribbon advancing mechanism. A bell crank 194 is mounted on a shaft 196 located rearward of the power roller 10. One arm 198 of the bell crank extends upward and is provided on its forward face with an ear 200 which may be disposed underneath an offset portion 202 of the cam unit frame member 153 that normally rests on the stud 156. This ear is urged forward toward that position by a spring 204 anchored on the stud 156 and connected to the other arm 206 of the bell crank so as to urge the bell crank clockwise about the shaft. A second spring 208 is connected to the bell crank to urge it counterclockwise. At one of its ends it engages theupstanding arm 198 on which the car 200 is mounted, and at its other end it engages a lever 210 fixed on the control shaft 192 to rotate with'it. The

springs

204 and 208 are so tensioned that when the control shaft 192 is in the counterclockwise position shown in which the lever is active to move the ribbon vibrator,

the spring 208 exerts a force on the bell crank sufiicient to overcome the tension of the'spring 204-and move the bell crank counterclockwise until the upstanding arm 198 thereof engages 'a fixed stop member 212. When,

however, the control shaft is rotated clockwise so as to inactivate the ribbon lever '54 and the ribbon vibrator 50, the clockwise swinging of the lever 210 decreases the tension in the spring 208 to a point where it is overcome by the tension in the spring 204 and the bell crank 194 is rotated clockwise until the car 200 engages the side of the offset .portion 202. Thereafter, the ribbon can be advanced but once after the stencilling operation is initiated, for'the car 200 will move to a position underneath the offset portion to prevent the return of the cam unit to its normal position in which the cam 158 can engage the power roller 10'when released. The stud 156 is disposed in the path ofmovement of the upstanding arm 1'98 and serves as a stop to limit the clockwise movement "of "-the bell'cra'nk. Theuppe'r end of the upstanding arm 198 of said bell crank is curved away from said rearward portion of the cam carrier to provide a camming surface for directing the power unit toward the ear.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention. it is the intention, therefore, to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. In a typewriter or like machine having a series of type bars bearing respectively characters of a number of different widths, and a ribbon bearing a transfer medium operatively disposed at the printing point in the common path of movement of said type bars, a power actuator, power units drivable by said actuator and operatively connected with the respective type bars, a series of initiating means for actuating selectively the respective power units, feed means operable to advance said ribbon, another power unit drivable by said actuator upon operation of any of said type bars, and means responsive to the operation of any of said type bars to couple said feed means with said another power unit for a movement proportional to the width of the character printed.

2. In a typewriter or like machine having a series of type bars bearing respectively characters of a number of different widths, and a ribbon bearing a transfer medium operatively disposed at the printing point in the common path of movement of said type bars, a power actuator, power units drivable by said actuator and operatively connected with the respective type bars, a series of initiating means for actuating selectively the respective power units, feed means operable to advance said ribbon, another power unit drivable by said actuator, means operable to actuate said another power unit upon the operation of any of said first named power units, and control means responsive to the operation of any of said first named power units to couple said feed means with said another power unit for a movement proportional to the width of the character printed.

3. In a typewriter or like machine having a series of type bars bearing respectively characters of a number of different widths, and a ribbon bearing a transfer medium operatively disposed at the printing point in the common path of movement of said type bars, a power actuator,

power units drivable by said actuator and operatively connected with the respective type bars, a series of initiating means for actuating selectively the respective power units, feed means operable to advance said ribbon, another power unit drivable from a normal position through a fixed range by said actuator upon operation of any of said type bars, means driven by said another power unit to operate said feed means in a ribbon advancing direction only, and control means operable upon actuation of those type bars printing characters of different widths than the rest to vary the drive imparted to said feed means operating means by said another power unit.

4. In a typewriter or like machine having a series of type bars bearing respectively characters of a number of different widths, and a ribbon bearing a transfer medium operatively disposed at the printing point in the common path of movement of said type bars, a power actuator, a series of power units for operating respectively each of the type bars and each having an element movable into engagement with said actuator, a series of character keys for moving respectively the elements of the power units for the corresponding type bars, feed means operable to advance said ribbon, another power unit to be driven by said actuator through a predetermined path of movement, a first member movable from a normal position by said another power unit through a fixed range, a second memher having a one-way connection with said feed means and a portion disposed in the path of movement of and biased toward the first member, a third member shiftable between positions in which it is disposed in and in which it is disposed out of the path of movement of said second member, and means operable by any of said first named power units to shift the third member between its positions according to the width of the character printed.

5. In a typewriting machine or the like having a series of type bars bearing respectively characters of a number of different widths, and a ribbon bearing a transfer medium operatively disposed at the printing point in the common path of movement of said type bars, a power actuator, a series of power units for operating respectively each of the type bars and each having an element movable into engagement with said actuator, a series of keys for moving respectively the elements of the power units for the corresponding type bars, feed means operable to advance said ribbon, another power unit operable through a predetermined path of movement and having an element movable into engagement with said actuator, a first lever operatively connected with said power unit for movement through a predetermined are from a normal position, a stepped lever having a one-way connection with said feed means and a portion disposed in the path of movement of and biased toward said first lever, biased means shiftable from a normal position in which it limits the biased movement of the stepped lever to a minimum to positions in which it can be engaged by the stepped portion of the lever and in which it is out of the path of movement of said lever, and means having elements re spectively operable upon the printing of characters having different widths to move said biased means from its normal position to its other positions.

6. In a typewriting machine or the like having a series of type bars bearing respectively two characters of a number of different widths and normally operative to print one of said characters, and a ribbon bearing a transfer medium operatively disposed at the printing point in the common path of movement of said type bars, a power actuator, a series of power units for operating respectively each of the type bars and each having an element movable into engagement with said actuator, a series of keys for moving respectively the element of the power units for the corresponding type bars, case shift mechanism selectively operable to cause said type bars to print the other of their characters, feed means operable to advance said ribbon, another power unit operable through a predetermined path of movement and having an element movable into engagement with said actuator, a first lever operatively connected with said power unit for movement through a predetermined arc from a normal position, a stepped lever having a oneway connection with said feed means and a portion disposed in the path of movement of and biased toward said first lever, biased means shiftable from a normal position in which it limits the biased movement of the stepped lever to a minimum to positions in which it can be engaged by the stepped portion of the lever and in which it is out of the path of movement of said lever, and means having elements positionable by said case shift mechanism to form different operating connections with the first named power units by which they are respectively operable according to the width of the character being printed to move said biased means from its normal position to its other positions.

7. In a typewriter or like machine having a carriage, a platen mounted on said carriage, a series of type bars bearing respectively characters of a number of different widths, a ribbon bean'ng a transfer medium operatively disposed in front of said platen and in the common path of movement of said type bars, and spacing mechanism embodying space selecting means for advancing the carriage in proportion to the width of the character printed, at power actuator, a series of power units for operating respectively the type bars and each having an element movable into engagement with said actuator, a series of character keys for moving respectively the elements of the power units for the corresponding type bars, feed means operable to advance said ribbon, another power unit to be driven by said actuator through a predetermined path of movement, a first member movable from a normal position by said another power unit through a fixed range, a second member having a one-way connection with said feed means and a portion disposed in the path of movement of and biased toward the first member, a third member shiftable between positions in which it is disposed in and in which it is disposed out of the path of movement of said second member, and means embodying the space selecting means of the spacing mechanism and operable to shift the third member between its positions according to the width of the character printed.

8. A variable ribbon advancing mechanism comprising a pair of rollers in driving relationship to each other for advancing a ribbon placed between them, a member movable in a fixed path from a normal position, a power unit having a fixed cycle of operation and connected to said member to move it through a predetermined range, a second member having a one-way connection with one of said rollers to rotate it and disposed in the path of movement of said first member, means biasing said second member toward said first member, and a third member movable from a normal position in the path of movement of said second member to another position in which it permits the second member to further approach said first member.

9. A variable ribbon advancing mechanism comprising a pair of rollers in driving relationship to each other for advancing a ribbon placed between them, a power unit pivotally mounted for swinging movement through a fixed are from a normal position, a lever connected with said power unit for movement thereby, a stepped lever having a one-way connection with one of said rollers and a portion disposed in the path of movement of said first lever, spring means biasing said stepped lever toward said first lever, and a member shiftable from a normal position in which it limits the biased movement of the stepped lever to a minimum to positions in which it can be engaged by the stepped portion of the lever and in which it is out of the path of movement of the stepped lever. 10. A variable ribbon advancing mechanism comprismg a pair of rollers in drivingrelationship to each other for advancing a ribbon placed between them, a power unit pivotally mounted for swinging movement through a fixed are from a normal position, a lever connected with said power unit for movement thereby, a stepped lever having a one-way connection with one of said rollers and a portion disposed in the path of movement of said first lever, spring means biasing said stepped lever toward said first lever, a member shiftable from a normal position in which it limits the biased movement of the stepped lever to a minimum to positions in which it can be engaged by the stepped portion of the lever and in which it is out of the path of movement of the stepped lever, control means operable to move said member if an amount of ribbon advancement greater than the minimum is desired, and means for actuating said power unit to operate said first lever thereafter.

11. In a typewriter or like machine having a series of type bars bearing respectively characters of a number of difierent widths, and a ribbon bearing a transfer medium operatively disposed at the printing point in the common path of movement of said type bars, a power actuator, power units drivable by said actuator and operatively connected with the respective type bars, a series of initiating means for actuating selectively the respective power units, feed means operable to advance said ribbon, another power unit drivable by said actuator upon operation of any of said type bars, means responsive to the operation of any of said type bars to couple said feed means with said another power unit for a movement proportional to the width of the character printed, a ribbon color control mechanism, and means shiftable upon the movement of said color control mechanism to stencil position to render said another power unit inoperative.

12. In a typewriter or like machine having a carriage, a platen mounted on said carriage, a series of type bars bearing respectively two characters of a number of different Widths and normally operative to print one of said characters, a ribbon bearing a transfer medium operatively disposed in front of said platen and in the common path of movement of said type bars, and spacing mechanism embodying space selecting means normally operative to advance the carriage in proportion to the width of the character on the type bar that is normally printed; a power actuator, a series of power units for operating respectively the type bars and each having an element movable into engagement with said actuator, a series of character keys for moving respectively the elements of the power units for the corresponding type bars, case shift mechanism selectively operable to cause said type bars to print the other of their characters and to adjust said space selecting mechanism so that the spacing mechanism advances the carriage in proportion to the width of the other characters, a ribbon feed mechanism comprising a pair of rollers in driving relationship with each other and having said ribbon placed between them, another power unit pivotally mounted for swinging movement through a fixed arc and having an element movable into contact with said actuator, a first lever connected with said power unit for movement thereby, a second lever having a one-way connection with one of said rollers and a portion disposed in the path of movement of and biased toward said first lever, a biased member shiftable from a normal position in which it limits the biased movement of the second lever to a minimum to a position in which it permits the second lever to further approach said first lever, means embodying the adjustable space selecting means of the spacing mechanism and operable to shift the biased member to its other position before said another power unit is operated if a character having a greater width than the rest is printed, means responsive to the operation of anyof said type bars to move the element of said another power unit into contact with said actuator, a ribbon color control mechanism, and means shiftable upon the movement of said color control mechanism to stencil position to render said another power unit inoperative.

13. In a typewriter or like machine having a carriage, a platen mounted on said carriage, a series of type bars bearing respectively characters of a number of different widths, a ribbon bearing a transfer medium operatively disposed in front of said platen and in the common path of movement of said type bars, and an escapement mechanism for advancing the carriage after each operation of a type bar; selectively actuable power means for operating the respective type bars and the escapement mechanism, feed means operable to advance said ribbon, means operable upon operation of any of said power means to drive said feed means so as to advance said ribbon, and control means distinct from said feed means drive means and said escapement mechanism and operable upon operation of the respective type bars to vary the operation of said feed means by its drive means according to the width of the character printed.

References Cited in the file of this patent UNITED STATES PATENTS 2,224,766 Dodge Dec. 10, 1940 2,411,723 Hausman Nov. 26, 1946 2,506,702 Chisholm May 9, 1950 2,609,077 Schroeder Sept. 2, 1952