US3891078A

US3891078A - Ribbon shifting arrangement

Info

Publication number: US3891078A
Application number: US450560A
Authority: US
Inventors: Friedrich Jung
Original assignee: Triumph Werke Nuernberg AG
Current assignee: TA Triumph Adler AG
Priority date: 1973-04-27
Filing date: 1974-03-13
Publication date: 1975-06-24
Anticipated expiration: 1992-06-24
Also published as: JPS5516680Y2; JPS5097511U

Abstract

A bichrome ribbon is carried in an upwardly biased ribbon fork for movement between a lowered position and a raised position to bring different colored portions adjacent one of a plurality of characters on a print wheel for being impacted by a platen carrying a recording medium. The print wheel is rotatably driven by a pivoting gear segment to position a selected character for printing, and the ribbon fork is normally limited to the lowered position by an armature of an unenergized control magnet which is spring biased into blocking relation with a control pawl linked to the ribbon fork. The ribbon is moved to the raised position by first energizing the control magnet to pull the armature from the control pawl, and to minimize the required strength of the control magnet the control pawl is held out of frictional engagement with the armature by a stop on the gear segment engaging the ribbon fork and holding it slightly below the lowered position when the gear segment is at its rest position. The subsequent movement of the ribbon fork to the raised position is in accordance with the movement of the gear segment, and the upward movement is limited by a stop pin engaging an end of an elongated slot in the control pawl as the ribbon fork reaches the raised position. After printing, the ribbon fork is returned to the lowered position by the stop on the gear segment as it moves to the rest position, whereupon the control magnet is deenergized to return the armature to blocking relation with the control pawl.

Description

21 Unites tates atet 1 1 1111 3,891,078

Jung June 24, 1975 RIBBON SHIFTING ARRANGEMENT [57] ABSTRACT I [75] Inventor; Friedrich Jung, Erlangen, Germany A bichrome ribbon is carried in an upwardly biased ribbon fork for movement between a lowered position [73] AsslgmeZ Tnumph werke Numberg and a raised position to bring different colored por- Numberg Germany tions adjacent one of a plurality of characters on a [22] Filed; Man 13 1974 print wheel for being impacted by a platen carrying a recording medium. The print wheel is rotatably driven [21] PP N 450,560 by a pivoting gear segment to position a selected character for printing, and the ribbon fork is normally lim- F i n A li ti Pri it D t ited to the lowered position by an armature of an un- Apr 27 1973 Germany 7316036 energized Control magnet which is Spring biased blocking relation with a control pawl linked to the rib- [52] U S Cl 197/156 97/151, 197/157. bon fork. The ribbon is moved to the raised position 197/159 by first energizing the control magnet to pull the ar- 51 1m. 01 B4lj /22 mature from the comm] Paw, and to minimize the [58] Field n 197 /49 51 55 144 151 quired strength of the control magnet the control pawl 97/154 156 157 d is held out of frictional engagement with the armature by a stop on the gear segment engaging the ribbon 56] References Cited fork and holding it slightly below the lowered position when the gear segment is at its rest position. The sub- UNITED STATES PATENTS sequent movement of the ribbon fork to the raised po- 3,304,859 2/1967 Schemc l97/l5l X Sition is in accordance with the movement of the gear spatgeutnyl. 192/9253; segment, and the upward movement is limited by a 3 1 5/1970 i g z d' 97/151 stop pin engaging an end of an elongated slot in the 366607O 5/1972 Schaefer "l97/49 X control pawl as the ribbon fork reaches the raised po- 3 795 3/1974 shimodai'r' iiilii 11 101 93 0 SitiOn- After Printing, the ribbon fork is returned t0 the lowered position by the stop on the gear segment Primary ExaminerEdgar S. Burr as it moves to the rest position, whereupon the control Assistant Examiner-R. T. Rader magnet is deenergized to return the armature to Attorney, Agent, or FirmJoseph R. Spalla blocking relation with the control pawl.

6 Claims, 2 Drawing Figures l7 I9 23 l /5 29 I Q; \r 7 1 37 I6 :F l :7

RIBBON SI-IIFTING ARRANGEMENT This invention relates to a printer, for example an electric calculating machine, and more particularly to an arrangement for shifting a conventional composite bichrome ribbon from a lowered position to a raised position to effect printing with different colored portions of the ribbon.

In the past, there have been ribbon shifting arrangements wherein a conventional composite bichrome ribbon is carried in a fork and moved from a lowered position to a raised position under the urging of a spring. The ribbon fork is normally held in the lowered position by a control pawl latched in engagement with the armature of a control magnet, and the ribbon is shifted to the raised position by energizing the control magnet to pull the armature from engagement with the pawl.

However, such an arrangement is disadvantageous because it necessitates a control magnet strong enough to overcome the frictional engagement of the armature with the control pawl. In addition, the sudden release of the ribbon fork may cause the ribbon to move at a speed resulting in travel past the desired upper position and consequently cause poor printing. Moreover, such a shifting of the ribbon is accompanied by undesirable noise.

Accordingly, an object of the invention is to provide a spring powered ribbon shifting arrangement which effects shifting under the control of a magnet without having to overcome the frictional engagement of a magnetic armature and a control pawl which also prevents movement of the ribbon beyond the upper position.

Still other objects, features and advantages of the present invention will be apparent to those skilled in the art from areading of the following detailed description of a preferred embodiment of the invention, taken in conjunction with the accompanying drawing, wherein:

FIG. 1 is a partial diagrammatic view ofa printer having a ribbon shifting arrangement constructed in accordance with the present invention and illustrating the arrangement in a rest condition with the ribbon conditioned for elevation to a first or black ribbon position; and

FIG. 2 is a view similar to FIG. 1 and illustrating the arrangement in an operated condition with the ribbon elevated to a second or red position.

Referring now in detail to the figures in the drawing, there is shown a printer, generally indicated 11, of an electric calculator for printing characters, such as numerals, on a recording medium 13. The recording medium 13 is supported on a platen 15 adjacent a print wheel 17 having a plurality of different characters 19 spaced along the periphery, and selected characters 19 may be positioned for printing by moving a gear drive, generally indicated by the arrow I in FIG. 1, to rotate the print wheel 17 and bring a desired character 19 into printing relation with the platen 15 such as shown in FIG. 2. Between the platen l and the type wheel 17, an inked ribbon 23 is mounted on conventional guide rollers 25 of a ribbon fork 27, and printing is effected by moving the platen in the direction indicated by the arrow II in FIG. 1 to impact the recording medium 13 along with the ribbon 23 against the desired character 19. After printing, the platen 15 is returned to its rest position and the print wheel 17 is reversely rotated as the gear drive 21 returns to the rest position shown in FIG. 1. In addition, the recording medium 13 may be advanced along the platen l5 and the ribbon 23 may be moved along the guide rollers 25.

As shown, the recording medium 13 is carried on a cylindrical platen 15 supported by a shaft 16, and the print wheel 17 is concentrically mounted on a rotatable shaft 29 along with a gear wheel 31. The gear wheel 31 forms a part of the gear drive 21 and meshes with a gear segment 33 mounted on a shaft 35 which may be rotatably driven by suitable means, not shown. The ribbon fork 27 is pivotally mounted on a shaft 37 with an arm 27 extending toward the gear segment 33, and the ribbon fork 27 is resiliently biased for movement to a raised position by a spring 39 stretched between the arm 27 and a suitable portion 40 of the printer 11.

As is conventional, the ribbon 23 may be a composite bichrome ribbon of red and black longitudinally extending stripes with the characters 19 normally being printed in black. The ribbon 23 is supported on the guide rollers 25 of the ribbon fork 27 with the black portion on top, and the ribbon fork 27 is adapted to be raised from the rest position shown in FIG. 1, to a first position or to a second higher position so that the upper black portion or the lower red portion of the ribbon 23 respectively is impacted against the selected character 19 during printing. As more particularly shown in FIG. 1, the spring-biased ribbon fork 27 moves from the rest position to the first or black position established by an armature 41 of a control magnet 43 normally positioned in blocking relation with a hook portion 45 of a control pawl 47 pivotally linked to the ribbon fork 27. The control magnet 43 is normally deenergized to present the black portion of the ribbon 23 for printing and the armature-41 is pivotally supported and resiliently biased into blocking relation with the control pawl 47 by a spring 49 suitably stretched between the armature 41 and the control magnet 43.

When it is desired to print a character in a different color, for example red, the ribbon 23 is raised to a second or red position, as shown in FIG. 2, to bring the lower or red portion of the ribbon 23 into printing relation with a selected character 19. To enable the ribbon fork 27 to rise to the second or red position under the urging of the spring 39 and as permitted by movement of the gear drive 21, the control magnet 43 is energized to pull the armature 41 away from the control pawl 47 against the urging of the spring 49.

To avoid frictional engagement between the armature 41 and the control pawl 47 as well as to control upward movement of the ribbon 23 to the raised position positions, in accordance with the present invention the ribbon shifting arrangement includes a projecting stop 51 on the gear segment 33 which engages the downwardly extending inwardly bent arm 27 of the ribbon fork 27 and holds it in rest position slightly below the first or black position when the gear segment 33 is in the rest position. Accordingly, when a character 19 is selected for printing using the upper or black portion of the ribbon 23, the movement of segment stop 51 away from arm 27' will permit the ribbon fork 27 to rotate about its pivot 37 clockwise until the hook portion 45 of the control pawl 47 engages the armature 41 of the deenergized magnet 43. However, when it is desired to print a character 19 using the lower or red portion of the ribbon 23, the control magnet 43 is energized to pull the armature 41 from blocking relation with the control pawl 47 and then the gear segment 33 is moved to position a selected character 19 for printing, thereby controlling, as stop 51 on the gear segment raised position, the control pawl 47 has an elongated slot 53 slidably receiving a stop pin 55 which engages an end of the slot 53 when the ribbon fork 27 reaches the second raised position.

After the character 19 is printed, the ribbon fork 27 is returned to the rest position shown in FIG. 1 by the engagement of the stop 51 with the arm 27' as the gear segment 33 returns to the rest position. Subsequently, the control magnet 43 is deenergized to enable the armature 41 to again move under the urging of the spring 49 into blocking relation with the control pawl 47.

What is claimed is:

1. In a printer, the combination comprising:

a print wheel supported for rotation about an axis and having a plurality of characters on the periphery with associated gear means for rotation therewith,

a gear segment cooperating with the gear means of said print wheel and being pivotally movable relative to a rest position for rotating the print wheel to position the different characters for printing,

a ribbon fork pivotally supported for movement from a rest position to a first raised position and a second raised position to bring different portions of the ribbon into printing relation with a selected character on the print wheel,

resilient biasing means urging said ribbon fork to a raised position,

a control pawl connected to said ribbon fork,

an armature of a control magnet normally located in blocking relation to the movement of said control pawl to limit the movement of said ribbon fork to said first raised position and being movable from blocking relation with said control pawl for en- 4 abling movement of said ribbon fork to the second raised position, and

said gear segment having an abutment thereon engaging said ribbon fork in the rest position prcventing movement of said ribbon fork to a raised position and permitting movement of said ribbon fork to a raised position only as the gear segment moves from its rest position to rotatably position a type character for printing.

2. In a printer according to claim 1, said ribbon fork being moved from a raised position to the rest position as said gear segment returns to its rest position.

3. In a printer according to claim 2:

said ribbon fork being held in said rest position with the control pawl spaced from said armature of the control magnet upon return of the gear segment to its rest position.

4. In a printer according to claim 3, the combination further comprising:

said control pawl having an elongated slot formed therein extending in the direction of movement of said ribbon fork between said rest and a raised position, and

a pin stop slidably received in the slot formed in said pawl and limiting the movement of said ribbon fork to the second raised position.

5. In a printer according to claim 1, the combination further comprising:

said pawl having an elongated slot formed therein extending in the direction of movement of said ribbon fork between said rest and a raised position, and

a pin abutment slidably received in the slot formed in said pawl and limiting the movement of said ribbon fork to the second raised position.

6. In a printer according to claim 1:

Claims

1. In a printer, the combination comprising: a print wheel supported for rotation about an axis and having a plurality of characters on the periphery with associated gear means for rotation therewith, a gear segment cooperating with the gear means of said print wheel and being pivotally movable relative to a rest position for rotating the print wheel to position the different characters for printing, a ribbon fork pivotally supported for movement from a rest position to a first raised position and a second raised position to bring different portions of the ribbon into printing relation with a selected character on the print wheel, resilient biasing means urging said ribbon fork to a raised position, a control pawl connected to said ribbon fork, an armature of a control magnet normally located in blocking relation to the movement of said control pawl to limit the movement of said ribbon fork to said first raised position and being movable from blocking relation with said control pawl for enabling movement of said ribbon fork to the second raised position, and said gear segment having an abutment thereon engaging said ribbon fork in the rest position preventing movement of said ribbon fork to a raised position and permitting movement of said ribbon fork to a raised position only as the gear segment moves from its rest position to rotatably position a type character for printing.

3. In a printer according to claim 2: said ribbon fork being held in said rest position with the control pawl spaced from said armature of the control magnet upon return of the gear segment to its rest position.

4. In a printer according to claim 3, the combinatin further comprising: said control pawl having an elongated slot formed therein extending in the direction of movement of said ribbon fork between said rest and a Raised position, and a pin stop slidably received in the slot formed in said pawl and limiting the movement of said ribbon fork to the second raised position.

5. In a printer according to claim 1, the combination further comprising: said pawl having an elongated slot formed therein extending in the direction of movement of said ribbon fork between said rest and a raised position, and a pin abutment slidably received in the slot formed in said pawl and limiting the movement of said ribbon fork to the second raised position.

6. In a printer according to claim 1: said ribbon fork being held in said rest position with the control pawl spaced from said armature of the control magnet upon return of the gear segment to its rest position.