US2986260A - Ribbon mechanism - Google Patents

Description

May 30, 1961 w. B. WHIPPO RIBBON MECHANISM 4 Sheets-Sheet 1 Original Filed Dec. 20, 1957 INVENTOR. WALTER B. WHlPPQ,

May 30, 1961 w. B. WHIPPO RIBBON MECHANISM Original Filed Dec. 20, 1957 16 FIG. 2

4 Sheets-Sheet 2 May 30, 1961 w. B. WHIPPO 2,986,260

RIBBON MECHANISM Original Filed Dec. 20, 1957 4 Sheets-Sheet I5 FIG.-4

y 1961 w. B. WHIPPO 2,986,260

RIBBON MECHANISM Original Filed Dec. 20, 1957 4 Sheets-Sheet 4 F I G. 5

I /m-s 186% United States Patent-C RIBBON MECHANISM Walter B. Whippo, Lexington, Ky., assignor to International Business Machines Corporation, New York,

7 N.Y., a corporation of New York Original application Dec. 20, 1957, Ser. No. 704,195,

npw Patent No. 2,902,136, dated Sept. '1, 1959. Digrodfgzgnd this application Apr. 21, 1959, Ser. No.

3 Claims. (Cl. 197-151) This invention relates to a cartridge'for an inked ribbon to be used with a printing mechanism, and more particularly to an improved cartridge which may be mounted as a single unit on a typewriter or similar printing machine and contains spools for a ribbon which may be advanced past printing elements. This application is a division of application, Serial Number 704,195, filed December 20, 1957, now Patent No. 2,902,136, for Ribbon Mechanism.

The usual construction of typewriter ribbon mechan isms includes a ribbon spool at each side of the typewriter, drive mechanism for feeding ribbon from one spool to the other past a printing position, and duplicate mechanisms at each ribbon spool for reversing the feed when ribbon is' exhausted from one spool whereby the exhausted supply spool becomes the driven take-up spool and the take-up spool becomes the supply spool.

By supporting the spools for rotation on axes closely adjacent to each other, it is possible to use a single feed mechanism like that of the above mentioned application for driving the two spools alternately. This may be accomplished by arranging the spools in a single container for rotation on spaced parallel axes. The ends of the spools are rotatably supported by opposite casing walls and open through the latter so they may be engaged at either end by driving means. This makes it possible tom ount the casing with either side up. By using flangeless spools, it is possible to arrange them closer to each other since the space required for the winding of ribbon on each may overlap with the other. As ribbon is unwound from one of the spools it is wound onto the other, and the spacing of the spools is made great enough only to avoid interference with winding operations. The upper and lower casing walls are spaced from each other a distance slightly greater than the width of the ribbon and perform the function of spool flanges in guiding the ribbon in overlapping turns on the spools. The ribbon passes through slots in the casing adjacent the spools to be supported in a position between a printing element and a platen. A typist may, without touching the ribbon, easily mount the casing on a typewriter with the spools connected to driving means and the ribbon passing through suitable guides. The complete unit including the casing and spools is inexpensive and may be discarded when the ribbon becomes worn out.

An object of this invention is to provide an improved ribbon cartridge.

Another object is to provide a ribbon cartridge comprising a casing enclosing a pair of spools having ribbon wound thereon and extending from one spool to the other through slots in the casing. Still another object is to provide a casing with a pair of flangeless spools enclosed therein, the ends of the spools being rotatably supported by opposite casing walls and extending through the latter for engagement by driving means, and including a ribbon wound on the spools and extending between them through slots in the casing.

Patented May 30, 1961 Yet another object is to provide an inexpensive ribbon cartridge including a pair of spools enclosed in a casing and adapted to be mounted on a typewriter with the spools engaging driving means while the ribbon extends through slots in the casing past a printing position.

Still another object is to provide an improved ribbon cartridge permitting clean and easy changing of ribbons.

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

In the drawings:

Figure 1 is a perspective view of the ribbon mechanism.

Figures 2 and 3 are operational plan views of the ribbon mechanism.

Figure 4 is a side elevation of the ribbon mechanism mounted on a carrier.

Figures 5 and 6 show a ribbon cartridge.

Referring to Figure 4, the ribbon mechanism generally designated 10 is mounted on a carrier 12 of the type illustrated in a copending application, Serial Number 653,806, title Keyboard Selection Mechanism, filed April 19, 1957, on behalf of Leon E. Palmer, now Patent No. 2,919,002, for use with a single print element typewriter wherein the platen is stationary and the single print element is moved across the platen to successive print positions. In the embodiment shown herein, the ribbon mechanism moves with the print head across the platen; however, the ribbon mechanism could be stationary for use with a conventional typewriter in which the platen moves to present successive print positions.

As described in the above cited patent application, a shaft 14 is rotated once for each print stroke and operates through a cam (not shown) to throw the print head 15 and a ribbon 16 against a platen 17 to effect printing of a character selected by rotation and tilting of the head 15. The same shaft 14 is utilized to operate the ribbon mechanism 10 in a manner described hereinafter. The ribbon mechanism 10 is adapted to receive a cartridge 18 containing two ribbon spools.

Referring to Figures 5 and 6, the ribbon cartridge 18 is shown with two flangeless spools 19. The cartridge 18 may be made of any suitable material, for example a transparent styrene. The cartridge comprises an upper wall 18-1, a lower wall 18-2 and a continuous side wall 18-3. The side wall 18-3 contains a pair of ribbon slots 18-4 to accommodate the ribbon 16 which extends from one spool 19 through one slot 18-4, through a ribbon guide, for example 30R, past a print position adjacent the platen 17, through another ribbon guide 30L through the other slot 18-4 to the other spool 19. The cartridge contains two slots 18-5 in the upper wall and two slots 18-5 in the lower wall for a purpose described hereinafter. The spools 19 have reduced end portions 19-1 which fit rotatably into holes 18-6 in the upper and lower walls of the cartridge 18. The upper and lower ends of each spool 19 contain a centering hole 19-2 and ten equally spaced holes 19-3 surrounding the hole 19-2. The slots 18-5 are for mounting the ribbon cartridge 18 on the ribbon mechanism 10 in a manner described hereinafter. The holes 19-2 aid in positioning the cartridge in the ribbon mechanism 10 whereas the holes 19-3 form' there are no flanges on the spools. The center distance between the spools is less than the full diameter of the ribbon on each spool. If flanges were provided on the spools, for example, for ratchet teeth the flanges would have to be as large as the full ribbon diameter and the center to center distance would have to be great enough to allow the flanges to clear each other. Since there are no flanges in the preferred embodiment, and only one spool can contain a full diameter of ribbon at a time, it is possible to bring the spool centers closed together. The upper and lower walls of the casing act in place of spool flanges for directing the ribbon onto the spools. The necessary spacing of the spool centers is such that, with half of the desired quantity of ribbon on each spool, there will be clearance between them.

Referring to Figure 1, the shaft 14 has a cam fixed thereto for operating the ribbon mechanism 10 during each revolution of the shaft. The ribbon mechanism 10 includes a base plate 22 having slots 24 adapted for mounting the ribbon mechanism on the carrier 12 by means of screws 26, shown in Figure 4. The base plate 22 has upturned flanges 27L and 27R adapted for .engaging the holes 18-5 in the upper or lower walls of the cartridge 18 for mounting said cartridge on the ribbon mechanism. The base plate 22 has a pair of turned up flanges 28L and 28R for use in a manner described hereinafter. A pair of ribbon tension arms 30L and 30R are pivotally mounted on the base plate 22 by respective studs 32L and 32R. The tension arms 30L and 30R have turned down flanges 34L and 34R, respectively. The tension arms 30L and 30R are connected together by a spring 36 fixed to studs L and 35R extending through arcuate slots 37L and 37R in the base plate 22, and the arms are biased by this spring in a counterclockwise and a clockwise direction, respectively. A reversing member 38 is freely mounted on top of the base plate 22 and carries a pair of turned down flanges 40L and 40R which rest adjacent the turned down flanges 34L and 34R of the tension arms. The reversing member 38 also carries a pair of turned up flanges 42L and 42R engaging a spring 44 which is retained in a notch 46L on the tension arm 30L and in a notch 46R on the tension arm 30R. The reversing member 38 is free floating as described hereinbefore and is retained in position between the flanges 28L, 28R, 34L and 34R by the spring 44.

A pair of ratchet wheels 48L and 48R are rotatably mounted on the base plate 22. Each ratchet wheel carries a spindle 50L and 50R in the center of therespective ratchet wheels and a pair of pins 52L and 52R on opposite sides of the respective spindles 50L and 50R. The spindles 50 engage the centering holes 19-2 of the spools 19 whereas the pins 52 engage the pairs of holes 19-3 to lock the spools 19 for rotation with the ratchet wheels 48L and 48R. The holes 19-25 are sufliciently close together that beveled edges of adjacent holes intersect in a manner whereby the pairs of pins 52 readily engage pairs of holes 19-3 for easy mounting of the cartridge 18 on the ribbon mechanism 10.

A cam follower 54 is oscillatably mounted in a'bracket 56 fixed to the carrier 12 by a screw 57. The cam follower 54 is pivotally joined to an indexing pawl ,58 by a stud 60. The pawl 58 is mounted in a bracket 62 fixed o the bottom of the base plate 22. The pawl 58 is freely mounted in the bracket 62 by means of a bevelled hole 64 whereby the pawl 58 may pivot about a horizontal axis running parallel to the shaft 14 in response to the movement of the cam follower 54, as 'well as about a horizontal axis running at 90 to the shaft 14 as described hereinafter. In Figure 1, the bracket 62 is shown detached and spaced from the base plate 22 for clarity and the pawl 58 is broken.

A detent member 66 is mounted on the base plate 22 by means of a pivot 68 and is connected to the upper .end of the pawl 58 by a spring 70. Each revolution of the shaft 14 and the ribbon feed cam 20 eflects an oscillation of the pawl 58 thereby effecting an indexing movement of the ratchet wheel 48L or 48R then engaged by the pawl 58. The detent member 66 engages the driven ratchet wheel 48L or 48R to prevent backward movement thereof. The reversing member 38 has three arms 72L, 72R and 74 on the end opposite the flanges 42L and 42R. The ribbon 16 carries a grommet 76, Figures 2 and 3, near each end of the ribbon, adapted to actuate the ribbon tension arms 30L and 30R. When the ribbon is exhausted, for example, from the spool 19 on the ratchet wheel 48R, as indicated in Figure 2, the grommet 76 in the ribbon 16 passing through an open end slot 77R, Figure 1, engages the ribbon tension arm 30R and, as the ribbon continues to feed onto the left hand spool 19, the arm 30R is pivoted counterclockwise about its pivot 32R as shown in Figure 2. As the arm 30R pivots counterclockwise, the flange 34R moves away from the flange 40R of the reversing member 38 and the tension of the spring 44, increased by the counterclockwise rotation of the ribbon guide 30R to which the right end of the spring 44 is fixed, draws the reversing member 38 in a clockwise direction about a pivot point formed at the flanges 34L and 40L. The right hand arm 72R of the member 38 swings to the left and moves behind an upturned flange 78R formed on the detent member 66. At the same time the arm 74 moves to the left and is interposed in the path of oscillation of the pawl 58 as shown in Figure 2. If the pawl 58 is in its advanced position at the time the arm 74 swings to the left, the arm 74 rests against the side of the pawl 58 until the pawl 58 is retracted at which time the arm 74 is interposed as described.

As shown in Figure 2, there is a component of force of the spring holding the pawl 58 in engagement with the ratchet wheel 48L. At the next forward movement of the pawl 58, the pawl advances the wheel 48L as before, but also engages the end of the arm 74, driving the reversing member 38 ahead of it. As the member 38 is driven back toward its normal position, a surface 79R on the arm 72R engages the upturned flange 78R on the detent member 66, thereby pivoting the member 66 in a counterclockwise direction. The detent member is driven against increasing tension of the spring 70 until such time as the spring 70 crosses the pivot point 68 (see dotted outline in Figure 3), at which time, the tension of the spring 70 then acts to snap the detent member 66 into engagement with the ratchet wheel 48R and to snap the pawl 58 to the right pivoting it about the horizontal axis referred to hereinbefore whereby it will engage the ratchet wheel 48K. The driving engagement of the pawl 58 with the ratchet wheel 48L is suflicient to maintain the panel 58 to the left as shown in dotted outline in Figure 3, as the leftward component of force of the spring 70 diminishes and then becomes a rightward force, until after the spring 70 crosses the pivot point 68. At the end of the power stroke of the pawl 58 when the driving engagement is released, the pawl 58 snaps over the ratchet wheel 48R. As the pawl 58 and the detent member 66 are both removed from engagement with the ratchet wheel 48L, the wheel 48L and the left hand spool 19 are free to rotate thereby relieving the tension of the ribbon 16 and permitting the ribbon tension arm 30R to return to its normal position and restore the reversing member 38 to its nor mal position. It will be noted that the complete reversal of the ribbon feed pawl 58 has taken place during the idle time between feed strokes.

One of the drawbacks to the conventional reversible ribbon feed mechanisms is that the last used point on each end of the ribbon is subjected to more wear than the intermediate points, due to the sluggish operation of these mechanisms, resulting in holes being worn at those end points. The life of the ribbon therefore is limited by the life of the end points, which is shorter than the useful life of the remainder of the ribbon. The ribbon mech anism illustrated and described herein permits only one print stroke at the end points of the ribbon thereby subjecting -the end points to actually less wear than the intermediate points of the ribbon and prolonging the useful life of the ribbon. This also reduces operating costs due to additional ribbons and time required to change ribbons.

The pawl 58 Will step the ratchet Wheel 48R in a wind ing direction during each rotation of the cam 20 until the spool 19 on the ratchet wheel 48L is exhausted, at which time, an operation similar to that described hereinbefore will take place to return the pawl 58 from the wheel 48R to the wheel 48L. In this operation, the ribbon tension arm 30L is pivoted clockwise permitting the reversing member 38 to pivot about a point formed by the flanges 34R and 40R to swing the arm 72L behind the lug 78L whereby the next oscillation of the pawl 58 will drive the reversing member 38 causing the detent member 66 to flip to the wheel 48L and draw the pawl 58 also to the wheel 48L.

It will be apparent that this invention may be practiced without departing from the spirit of the invention, by using ribbon spools, either in or out of a cartridge, having toothed flanges rather than by mounting flangeless spools on the illustrated ratchet wheels, or by using flangeless spools without the cartridge.

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 following claims.

What is claimed is:

1. An inked ribbon cartridge comprising, in combination, a casing having upper and lower supporting walls extending parallel to each other, a side wall permanently connected at its edges to said upper and lower walls to form a single enclosed chamber, a pair of spools arranged in said chamber and having ends supported by said upper and lower walls for rotation on spaced parallel axes, at least one end of each of said spools extending through one of said supporting walls for engagement by driving means, ribbon slots formed in said side wall, and an inked ribbon wound at its ends on said spools and extending between the latter through said slots.

2. The cartridge of claim 1 in which said spools are flangeless and are spaced from each other a distance less than twice the radius of a coil of ribbon when fully wound on one of said spools.

3. The cartridge of claim 1 in which both ends of said spools open through said supporting walls for engagement selectively by driving means.

References Cited in the file of this patent UNITED STATES PATENTS 928,001 OConnor July 13, 1909 2,304,498 Hart Dec. 8, 1942 2,359,502 Wyrick Oct. 3, 1944 2,764,934 Kaplan Oct. 2, 1956

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