US3147703A

US3147703A - Columnar rack printer with ribbon shift alternator

Info

Publication number: US3147703A
Application number: US232199A
Authority: US
Inventors: Donald J Smithbauer
Original assignee: Burroughs Corp
Current assignee: Unisys Corp
Priority date: 1962-10-22
Filing date: 1962-10-22
Publication date: 1964-09-08
Anticipated expiration: 1981-09-08

Description

p 1964 D. J. SMlTHBAUER COLUMNAR RACK PRINTER WITH RIBBON SHIFT ALTERNATOR 3 Sheets-Sheet 1 Filed Oct. 22, 1962 EQU N IN VENTOR. DONALD J. sun/mum.

A T TORNE X COLUMNAR RACK PRINTER WITH RIBBON SHIFT ALTERNATOR Filed Oct. 22, 1962 Sept. 8, 1964 D. J. SMITHBAUER 3 Sheets-Sheet 2 INVENTOR. 00mm J SMITHBAl/ER.

ATTORNEY Sept. 8, 1964 D. J. SMITHBAUER 3,147,703

COLUMNAR RACK PRINTER WITH RIBBON SHIFT ALTERNATOR Filed Oct. 22, 1962 3 Sheets-Sheet 5 (\I N u:

gr QD co an L0 -J 2 5 fl 0 N5 :5 W j 3 i :2, r- 4.

co 2; co

ro*\ n H) g I. :2 co

"' INVENTOR. DONALD J SMITHBAUER.

AT TORNEK thereon.

.of the ribbon lift spindles. "part of a cyclically operable ribbon advancing mechanism United States Patent 3,147,703 CQLUMNAR RACK PRINTER WITH RIBBON SIEHET ALTERNATQR Donald J. Smithbauer, Detroit, Mich, assignor to Barroughs (Iorporation, Detroit, Mich, a corporation of Michigw Filed Get. 22, 1962, Ser. No. 232,199 7 Claims. (6!. 101 336) This invention relates to ink ribbon printing devices, and, more particularly, to ribbon field selection apparatus for ribbon lifting mechanisms.

The invention seeks generally to improve the uniformity of printing density across an entire printing line and to prolong the serviceability of inked ribbons from the standpoint of ribbon wear and life in printing devices using an inked ribbon.

Towards the accomplishment of these aims and objects, the invention provides an alternator for a ribbon shift mechanism that automatically alternates the shift or lift of the ribbon to the upper half and to the lower half thereof on successive printing cycles or operations of a printing device.

For an appreciation of the manner in which the above and other objects of the invention are attained, reference is made to the following description and attending drawings, in which:

FIG. 1 is an exploded, isometric view, with parts broken away, of a part of a printing apparatus embodying the essential elements of the ribbon shift alternator mechanism of the present invention;

FIG. 2 is a side elevation view taken from the right of FIG. 1;

FIGS. 3 and 4- are views illustrating different positions of the subject alternator mechanism to explain the operation of the invention, and

FIG. 5 is a top plan View showing the relative lateral spacings of the parts of the subject alternator mechanism.

Referring to the drawings, FIG. 1 illustrates an improved ribbon lift and control mechanism for a full line, word printer of the type described more fully in copending US. application S.N. 17,200, filed March 23, 1960, for

William W. Deighton, of common ownership herewith,

the side frames is a pair of supporting guide brackets 14,

15 for a pair of ribbon lift spindles 16, 17. Each spindle mounts a ribbon spool 19, 20 carrying an ink ribbon 21 extending therebetween and of such width relative to the printing type faces of the printer as to provide two printing field corresponding to the upper half 21U and to the .lower half 21L of the ribbon. Mounted rearwardly of the ribbon is a platen 22 having a print receiving record medium 23, such as a ledger card, journal roll or tape, rolled Iournalled in and extending through the side frames is a rotatable ribbon lift shaft 24 having fixed to each end thereof a rearwardly extending

lift arm

25, 26, each having a slotted end attached by an adjustable stud and nut 27, to the intermediate portion of a respective one Also shown in FIG. 1 is a 28, which is similar to that employed in T. M. Butler Patent No. 2,629,549 and operates in conjunction with the ribbon shift alternator mechanism herein although forming no part thereof.

Near the inside of the right side frame 13, a dual arm and cam follower assembly, comprised of a short arm 30 and a long, cam follower arm 31 is provided on the ribbon lift shaft 24. The short arm 30 is pinned to the shaft through a hub portion secured to the upper end thereof and is forwardly tensioned by spring 33 secured to a stud on the right side frame, thereby urging the ribbon spindles to limit downwardly on their mounting brackets and positioning the ribbon in an inactive position below the printing line indicated by the dashed and dotted line on the record medium 23 in FIG. 1. The longer arm 31 is pivotally mounted through its center on a stud 34 secured to and passing through the lower end of the shorter arm and includes an elongated opening 35, shown in FIGS. 2, 3 and 4, in its upper end through which passes the lift shaft 24. The lower end of the arm 31 carries a cam follower roller 37 and is forwardly biased by spring 38 to tension the roller to the cam surface of a cam 40 secured to and carried on the cam drive shaft 39 of the printing device. The drive shaft is journalled in and extends through the side frames and is belt driven from a continuously running motor (not shown) through a onerevolution clutch 41, the tripping of which initiates a printing cycle.

In order that a print take place on the upper half or field of the ribbon, the lift arms receive the lesser of two possible elevating or vertical lift motions. During an upper ribbon field print cycle, the cam 40 attached to the main cam shaft 39 causes the follower arm 31 to pivot about stud 34 in a counterclockwise direction, as viewed from the right side of the printer device as in FIG. 2, without imparting motion to the stud, until such time as the right or rearwardly disposed end wall of the elongated slot 35 limits against the ribbon lift shaft 24. Upon a further camming of the follower arm 31, it no longer pivots on stud 34, but transfers its counterclockwise motion through the stud to the short arm 30, which, being pinned to the lift shaft, rotates the shaft counterclockwise to swing the

lift arms

25, 26 upwardly and lift the ribbon from an inactive position, 1, below the print line to a first raised position, R1, where the upper ribbon field 21U is in line with the active type, the inactive and raised ribbo positions being indicated in FIG. 2.

In order to provide a greater lift to the ribbon so that the lower half or ribbon field 21L thereof will be presented to the printing line, there is provided an interposer 43 in the form of a bail that is pivotally mounted on a stud 44 secured to and extending inwardly from the right side frame 13. The interposer includes an extended tab portion 46, which in FIGS. 2 and 3 is shown out of the path of a stepped notch or cut-out portion 47 provided on the upper end of the cam follower arm 31. By displacing the interposer tab downwardly to engage the shouldered cutout portion of the follower arm, the follower arm is prevented from shifting as much in the slot 35 and the interposer tab 46 acts as a limit stop or fulcrum for the follower arm. Since there is not as much lost motion of the follower arm on the lift shaft than in the previously described upper ribbon field printing cycle or operation, a greater motion is transferred to the shorter arm 30 and to the lift shaft with a consequent greater lift of the ribbon spindles to a higher elevation or second raised position, R2, where the lower half 21L or field of the ribbon will be aligned with the line of active printing type.

In accordance with the present invention, the interposer is automatically rocked into and out of the path of the follower arm 31 on successive printing cycles or operations by an alternator mechanism 56 which causes the upper half and lower half of the advancing ribbon to be alternately presented to the print line in order to provide uniform printing density thereacross and to prolong the service life and decrease the wear of a monochrome ribbon. The ribbon lift alternator is a bistable type reversing device, which in the illustrated form of the invention, is a mechanically actuated spring toggle mechanism comprising a rocker element 51, a cyclically operable driver arm 52 and an over-center compression spring 53.

As defined by the dictionary and common usage, the terms alternate and successive both mean one following the other. Also, the dictionary definition of the term alternate includes the meaning of successive. Accordingly, as used herein, alternate connotes change of position; whereas, successive connotes a time relationship.

The rocker element is a semi-circular disc having a pair of contiguous, upper and lower scallop-

shaped camming surfaces

55, 56 formed therein and located above and below its central mounting on a stud 57. Stud 57 extends inwardly from and its mounted on the right side frame 13 and carries a bracket 58 fixed thereon for guiding the toggle spring 53 of the alternator mechanism. The intersection of the cut-out

camming portions

55, 56 of the rocker element forms a rearwardly directed, centrally located peaked or nose portion 59, the tip of which is on a line passing through the pivot center of the rocker element. Integrally formed on the forwardly facing diametrical edge or surface of the rocker element is a downwardly canted protuberance 60 for receiving one end of the compression spring 53 thereon.

The driver arm 52 has a forwardly pointed end, which is adapted to engage and to be positioned in either of the camming surfaces of the rocker element, and is connected at its other end by a centering spring 61 to a rod or stud 62 carried on an end bracket arm 63 secured to the existing hammer latch bail 64 of the printing device shown in the aforementioned Deighton application.

Extending forwardly of the laterally extending hammer latch bail and connected to the aforesaid rod 62 on the end bracket 63 thereof is a drive link 65 which is pivotally connected near its forward end to the upper end of a cam follower rocker arm 66 that is pivotally mounted intermediate its ends to the lift shaft 24. The lower end of the rocker arm 66 carries a roller 67 and is forwardly tensioned by a spring 68 against another cam 69 carried on the main cam shaft 59. The driver arm 52 is coupled to the drive link 65, which drives the hammer latching bail, through a broken joint connection which includes a rod 70 slidably mounted in and extending through an elongated slot 71 in the drive link. A drive spring 72 for the broken joint is connected at one end to an inwardly extending stud 73 on the forward end of the drive link, the other end of the spring being connected to one end of the rod 70 thereby urging the rod 70 against the forwardly disposed wall of the slot provided in the link. The rod 76 provides a pivot mounting for the drive arm 52 through a centrally located hub 54 provided on the latter member.

The toggle spring 53 is connected between the downwardly canted protuberance 6ft projecting from the rocker element 51 and a rearwardly projecting protuberance 77 on an arm portion 78 of the interposer bail 43. The spring coupling the rocker element and interposer bail is under compression therebetween and exerts continual pressure against them. Therefore it acts as an over center toggle displaced above or below a line drawn through the respective pivot centers of the rocker element and interposer bail, and, thus holds these two parts in their last position.

With reference to FIGS. 2, 3 and 4, the rocker element 51 is forcibly tipped into one position or the other by the driver arm 52, which is urged forward under strong spring tension by the drive spring 72 to position the spear pointed end thereof in one or the other of the scalloped cut-out

camming portions

55 or 56 of the rocker element under which conditions the driver arm will be tipped on its pivot above or below the center of the rocker element. At the beginning of each print cycle or operation and prior to the movement of the lift shaft 24 through the follower arm 31, the driver arm 52 is moved rearwardly out of the rocker element without displacing the setting or position of the rocker element and interposer. As the driver arm is withdrawn from the rocker element, which is shown as being tipped downwardly in FIG. 3, the arm will rock slightly clockwise about the pivot rod as the arm is withdrawn from the lower cut-out camming portion 56 of the rocker element, and is restored to a center position established by the centering spring 61 and pivot rod, under which conditions the pointed end of the driver arm will be directed toward the pivot center and above the downwardly tipped nose 59 of the rocker element, as shown in FIG. 2.

The rearward movement of the driver arm is effected through the action of the cam follower rocker arm 66, which is pivoted clockwise at the beginning of the print cycle by the tensioned spring 68 and causes the drive link 65 carrying the pivot rod 7 ii of the driver arm to shift rearwardly and thereby to remove the tipped end of the latter from the rocker element 51. During the subsequent rotation of the cam 6h, the motion of the rocker arm 66 is reversed, and it is pivoted counterclockwise to cause the drive link 65 and the centered driver arm 52 to shift forwardly until the point of the driver arm engages the upper cam surface 55 of the rocker element 51. As the driver arm is shifted forwardly, it switches or reverses the rocker element to the opposite position, carrying the interposer 43 and toggle spring 53 therewith. The latter then holds the parts in their transferred position of FIG. 4 in which the interposer tab 46 is positioned in the path of the shouldered cut-out portion 47 of the follower arm 31.

This action is illustrated diagrammatically in FIGS. 2, 3 and 4 in which FIG. 3 illustrates the position of the interposer, rocker element and driver arm at the completion of an upper ribbon field printing cycle during which the lift arms received the minimum or lower lift by reason of theinterposer having been positioned out of the path of the cam follower arm 31. The elongated slot 35 in the follower arm is seen to provide a substantial amount of lost motion of the arm relative to the lift shaft 24 as the arm is swung counterclockwise by cam 40 and clockwise by the spring 38.

FIG. 2 illustrates the driver arm pulled rearward out of the upper scalloped cam portion 55 of the rocker element and nearly centered, the spear tipped end of the driver arm rising slightly above the downwardly tipped nose 59 of the rocker element to a position where it will engage the upperside of the nose portion 59 and be directed into the upper scalloped cam portion 55 of the rocker element. Thus, as the driver arm is driven forwardly, the upper cam portion will be presented thereto and will be cammed thereby above center to rock the rocker element counterclockwise about its pivot to the position approximated in FIG. 4, switching the toggle spring below center with concomitant downward or clockwise rocking of the interposer into the path of the follower arm 31. The retraction and repositioning of the driver arm was effected by the rocker arm 66, which, as previously described, positions the drive link 65 and hammer latch bail 64 prior to the movement of the lift shaft 24 by the follower arm 31, but during the same printing cycle.

With the interposer tab 46 positioned to engage the notch 47 in the follower arm 31, as shown in FIG. 4, the amount of lost motion of the follower arm will be decreased, thus causing the short arm 30 to initiate rotation of the lift shaft at a somewhat earlier time than that obtained by the orientation shown in FIG. 3. Accordingly, the lift spindles will receive a greater lift and be positioned to a higher lift position corresponding to the lower ribbon field. On the following printing cycle or operation, the previously mentioned ribbon advancing mechanism 28 advances the ribbon longitudinally a slight distance and the alternator mechanism reverses the position of the rocker element, toggle spring and interposer back to the minimum lift controlling position shown in FIG. 3 to cause printing through the advanced ribbon on the opposite printing field thereof, it being understood that the ribbon is advanced on each printing cycle.

What is claimed is:

1. In a printing device including a ribbon having two printing fields corresponding to respective halves of the ribbon, the combination of, a mounting frame, a ribbon supporting means mounted for movement on the frame, movable shifting means coupled to said ribbon support means to shift the latter from an inactive ribbon printing position to an active ribbon printing position in which one of said ribbon printing fields is positioned for printing therethrough, interposer means mounted on said frame and operable to be interposed in the path of movement of said shifting means to alter the movement thereof and modify the shift imparted to the ribbon supporting means to another active ribbon printing position in which the other one of said ribbon printing fields is positioned for printing therethrough, a mechanically positionable toggle mechanism mounted on said frame and coupled to said interposer to position the latter in the path of said shifting means in one position of the toggle mechanism and out of the path of the shifting means in another position thereof, and driver means alternating the position of the toggle on successive printing operations of said printing device to control the operation of said shifting means through said interposer means for printing on alternate halves or fields of the ribbon on successive printing operations of said printing device.

2. In a cyclically operable printing device including a ribbon having two printing fields corresponding to the upper half and to the lower half of the ribbon, the combination of a mounting frame, a ribbon supporting means mounted for vertical movement on the frame, a cyclically operable moveable lift means coupled to said ribbon supporting means to lift the latter vertically from an inactive ribbon printing position below an established printing line to an active ribbon printing position in which one of said ribbon printing fields is positioned at said line, interposer means mounted on said frame and operable to be interposed in the path of movement of said lift means to alter the movement thereof and modify the vertical lift imparted to the ribbon supporting means to another active ribbon printing position in which the other one of said ribbon printing fields is positioned at said line, a rocker element pivotally mounted to the frame and rockable to either of two positions, a compression spring coupling between said rocker element and said interposer, and a cyclically Operable driver arm drivingly engaging the rocker element and alternating the position of the latter on successive printing cycles of said printing device to control the operation of said lift means through said interposer means for printing on alternate halves of the ribbon on successive printing cycles of said printing device.

3. In a cyclically operable printing device including a ribbon having two printing fields corresponding to the upper half and to the lower half of the ribbon, the combination of a mounting frame, a ribbon supporting means mounted for vertical movement on the frame, a cyclically operable moveable lift means coupled to said ribbon supporting means to lift the latter from an inactive ribbon printing position below an established printing line to an active ribbon position in which one of said ribbon printing fields is positioned at said line, interposer means pivotally mounted on said frame and operable to be interposed in the path of movement of said lift means to alter the movement thereof and modify the lift imparted to the ribbon supporting means to another active ribbon position in which the other one of said ribbon printing fields is positioned at said line, a rocker element pivotally mounted on said frame to either of two positions and spaced from the said interposer means, a compression spring of greater length than the spacing between said interposer means and rocker element and connected therebetween to form an over-center toggle mechanism therewith, and a cyclically operable driver arm drivingly engaging the rocker element and alternating the position thereof on successive printing cycles of said printing device to control the operation of said lift means through said interposer means for printing on alternate halves of the ribbon on successive printing cycles of said printing device.

4. The combination in accordance with claim 3 above wherein said rocker element includes a pair of camming surfaces located above and below the pivot center thereof and alternately cooperating with said driver arm.

5. In a printing device including a ribbon having two printing fields corresponding to respective halves of the ribbon, a mounting frame, a ribbon supporting means mounted for movement on the frame, and movable shifting means coupled to said ribbon support means to shift the latter from an inactive ribbon printing position to an active ribbon printing position in which one of said ribbon printing fields is positioned for printing therethrough; a shift control mechanism controlling the shifting of the ribbon from said inactive ribbon printing position to alternate ones of two different ribbon printing positions on successive printing operations of said device, said shift control mechanism comprising, interposer means mounted on said frame and operable to be interposed into the path of movement of said shifting means for altering the movement thereof and modifying the shift imparted to the ribbon supporting means to another active ribbon printing position in which the other one of said ribbon printing fields is positioned for printing therethrough, a bistable element coupled to said interposer to position the latter in the path of said shifting means in one position of the bistable element and out of the path of the shifting means in another position thereof, and driver means alternating the position of the bistable element on successive printing operations of said printing device to control the operation of said shifting means through said interposer means for printing on alternate halves or fields of the ribbon on successive printing operations of said printing device.

6. In a device for printing a full line at a time, said device including a shiftable support for a ribbon having at least two ribbon printing fields thereon, a shift mechanism operable on successive operations of said printing device to shift the ribbon support from an inactive ribbon printing position on one side of an established printing line to different ones of at least two active printing positions each corresponding to a different one of said printing fields of said ribbon, said shift mechanism including control means settable to at least two different conditions each corresponding to a different one of said ribbon printing fields and controlling the extent of movement of said shiftable ribbon support from said inactive ribbon printing position to any one of said active ribbon printing positions in accordance with the condition of said settable control means, and setting means coupled to said settable control means and actuatable upon initiation of each printing operation to change the condition of said settable control means from its previous condition to a successive one of its conditions on different similar printing operations of said printing device.

7. In a cyclically operated printing device employing a ribbon having a plurality of printing fields dividing the width of said ribbon into a plurality of parallel bands for printing on an established print line, a shiftable ribbon supporting mechanism, means for shifting said mechanism, lost motion means between said shifting means. and said ribbon supporting mechanism enabling the shifting of said ribbon variable amounts on successive cyclical operations of said printing device from an inactive printing position on one side of said established print line to active printing positions superimposed upon said print line corresponding to diflerent ones of said ribbon printing fields, said shifting means including a cyclically actuated lost motion varying means having plural stable states coupled to said lost motion means for variably shifting said ribbon amounts corresponding to each of said active printing positions, and cyclical drive means coupled to said lost motion varying means and altering its stable state once during each cycle of said printing device.

References Cited in the file of this patent UNITED STATES PATENTS UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,147 703 September BTHI964 Donald J. Smithbauer It is hereby certified that error appears in the above-numbered patent requiring correction and that the said Letters Patent should read as corrected below,

Column 6, line 72, for "successive" read. diiferent line 73, for "different" read successive Signed and sealed this 20th day of April 1965,

'(SEAL) 1\Ltest:

ERNEST W. SWIDER v EDWARD J. BRENNER Attesting Officer Commissioner of Patents

Claims

1. IN APRINTING DEVICE INCLUDING A RIBBON HAVING TWO PRINTING FIELDS CORRESPONDING TO RESPECTIVE HALVES OF THE RIBBON, THE COMBINATION OF, A MOUNTING FRAME, A RIBBON SUPPORTING MEANS MOUNTED FOR MOVEMENT ON THE FRAME, MOVABLE SHIFTING MEANS COUPLED TO SAID RIBBON SUPPORT MEANS TO SHIFT THE LATTER FROM AN INACTIVE RIBBON PRINTING POSITION TO AN ACTIVE RIBBON PRINTING POSITION IN WHICH ONE OF SAID RIBBON PRINTING FIELDS IS POSITIONED FOR PRINTING THERETHROUGH, INTERPOSER MEANS MOUNTED ON SAID FRAME AND OPERABLE TO BE INTERPOSED IN THE PATH OF MOVEMENT OF SAID SHIFTING MEANS TO ALTER THE MOVEMENT THEREOF AND MODIFY THE SHIFT IMPARTED TO THE RIBBON SUPPORTING MEANS TO ANOTHER ACTIVE RIBBON PRINTING POSTION IN WHICH THE OTHER ONE OF SAID RIBBON PRINTING FIELD IS POSITIONED FOR PRINTING THERETHROUGH, A MECHANICALLY POSITIONABLE TOGGLE MECHANISM MOUNTED ON SAID FRAME AND COUPLED TO SAID INTERPOSER TO POSITION THE LATTER IN THE PATH OF SAID SHIFTING MEANS IN ONE POSITIN OF THE TOGGLE MECHANISM AND OUT OF THE PATH OF THE SHIFTING MEANS IN ANOTHER POSITION THEREOF, AND DRIVER MEANS ALTERNATING THE POSITION OF THE TOGGLE ON SUCCESSIVE PRINTING OPERATIONS OF SAID PRINTING DEVICE TO CONTROL THE OPERATION OF SAID SHIFTING MEANS THROUGH SAID INTERPOSER MEANS FOR PRINTING ON ALTERNATE HAOVES OR FIELDS OF THE RIBBON ON SUCCESSIVE PRINTING OPERATIONS OF SAID PRINTING DEVICE.