US3554349A

US3554349A - High-speed printer having improved ribbon tensioning and reversing drive mechanism

Info

Publication number: US3554349A
Application number: US734467A
Authority: US
Inventors: Donald G Hebert
Original assignee: General Electric Co
Current assignee: Genicom Corp
Priority date: 1968-06-04
Filing date: 1968-06-04
Publication date: 1971-01-12
Anticipated expiration: 1988-01-12

Abstract

A high-speed printer of the type having an inked ribbon traversing across a printing area and which is selectively movable to permit character impression and subsequent visibility of the character formed. A pair of pivoted cantilever arms are provided on each side of the printing area of the high-speed printer with a first ribbon guide being mounted adjacent the end of each pivoted cantilever arm. The inked ribbon is supported under tension between the two guides across the width of the printing area and pivoting means are provided for pivoting the cantilever arms in unison about a common pivot axis whereby the printing ribbon is selectively moved as a relatively rigid beam between the printing and viewing positions by pivotal movement of the cantilever arms. A second ribbon guide is mounted on each side of the high-speed printer for supporting the ribbon at points intermediate ribbon takeup and payout spools and the respective first ribbon guides. Each of the second ribbon guides are mounted with their peripheral surface supporting the ribbon in axial alignment with the pivot axis of the pivoted cantilever arm and the ribbon is twisted through substantially a right angle in the space between each second ribbon guide and its associated first ribbon guide so as to extend along a path that bisects the angular movement of the pivoted cantilever arms. Reversible, tensioning ribbon spool drive mechanisms are supported on opposite sides of the high-speed printer for moving the ribbon in either direction between the pair of takeup and payout spools. The spool drive mechanisms are selectively operable alternately to cause the spools to take up or pay out the ribbon and comprise rotatable supporting plates having driving and neutral freewheeling positions. A movable center gear and ratchet arrangement is supported on each supporting plate and coacts with a fixed center gear when the rotatable supporting plate is in its driving position. A spindle for supporting a ribbon spool is rotated by the fixed center gear and includes an actuable finger which is extended upon exhaustion of a ribbon from a spool under conditions where the spool is operating as a payout spool with the supporting plate in its neutral freewheeling position. An interposer lever is actuated by the extended finger upon exhaustion of the ribbon from the spool which then coacts with the ratchet to rotate the rotatable supporting plate from its neutral freewheeling position into a driving position thereby reversing the operation of the spool. A rotatable shaft interconnects the ribbon spool drive mechanisms on opposite sides of the printer with respective connecting links interconnecting the supporting plate of each spool drive mechanism with the rotatable shaft in a manner such that rotation of one of the supporting plates from the neutral freewheeling position to the driving position results in automatic rotation of the opposite supporting plate from the driving position to the neutral freewheeling position thereby providing jam-proof operation.

Description

United States Patent [72] Inventor Donald G. Hebert Rochester, N.Y. [2]] Appl. No. 734,467 [22] Filed June 4, 1968 [45] Patented Jan. 12, 1971 [7 3 Assignee General Electric Company a corporation of New York [54] HIGH-SPEED PRINTER HAVING IMPROVED RIBBON TENSIONING AND REVERSING DRIVE 'MECHANISM 17 Claims, 3 Drawing Figs.

[52] U.S.Cl 197/154, 101/96, [97/160, 101/336 [51] lnt.Cl ..B4lj33/02, B4lj33/5l [50] FieldofSearch 197/151,

154,155, 157, 160l65; 101/96RC,93RC, 100,

Primary Examiner-William B. Penn Attorneys-Lawrence G. Norris, Michael Masnik, Stanley C;

Corwin, Frank L. Neuhauser, Oscar B. Waddell and Melvin M. Goldenberg l ABSTRACT: A high-speed printer of the type having an inked ribbon traversing across a printing area and which is selectively movable to permit character impression and subsequent visibility of the character formed. A pair of pivoted cantilever arms are provided on each side of the printing areaof the.

high-speed printer with a first ribbon guide being mounted adjacent the end of each pivoted cantilever arm. The inked ribbon is supported under tension between the two guides across the width of the printing area and pivoting means are provided for pivoting the cantilever arms in unison about a common pivot axis whereby the printing ribbon is selectively moved as a relatively rigid beam between the printing and viewing positions by pivotal movement of the cantilever arms. A second ribbon guide is mounted on each side of the high-speed printer for supporting the ribbon at points intermediate ribbon takeup and payout spools and the respective first ribbon guides. Each of the second ribbon guides are mounted with their peripheral surface supporting the ribbon in axial alignment with the pivot axis of the pivoted cantilever arm and the ribbon is twisted through substantially a right angle in the space between each second ribbon guide and its associated first ribbon guide so as to extend along a path that bisects the angular movement of the pivoted cantilever arms. Reversible, tensioning ribbon spool drive mechanisms are supported on opposite sides of the high-speed printer for moving the ribbon in either direction between the pair of takeup and payout spools. The spool drive mechanisms are selectively operable alternately to cause the spools to take up or pay out the ribbon and comprise rotatable supporting plates having driving and neutral freewheeling positions. A movable center gear and ratchet arrangement is supported on each supporting plate and coacts with a fixed center gear when the rotatable supporting plate is in its driving position. A spindle for supporting a ribbon spool is rotated by the fixed center gear and includes an actuable finger which is extended upon exhaustion of a ribbon from a spool under conditions where the spool is operating as a payout spool with the supporting plate in its neutral freewheeling position. An interposer lever is actuated by the extended finger upon exhaustion of the ribbon from the spool which then coacts with the ratchet to rotate the rotatable supporting plate from its neutral freewheeling position into a driving position thereby reversing the operation of the spool. A rotatable shaft interconnects the ribbon spool drive mechanisms on opposite sides of the printer with respective connecting links interconnecting the supporting plate of each spool drive mechanism with the rotatable shaft in a manner such that rotation of one of the supporting plates from the neutral freewheeling position to the driving position results in automatic rotation of the opposite supporting plate from the driving position to the neutral freewheeling position thereby providing jam-proof operation.

HIGH-SPEED PRINTER HAVING-IMRROVED RIBBON 'TENSIONING AND REVERSING DRIVE MECHANISM BACKGROUND OF T'l-lE'lNVENTlON terminal printers for computer readout, and the like generally utilize electromechanically actuated ribbon positioning mechanisms, similar to those employed in :conventional typewriters, wherein a printing, inked ribbonnorrnally is in ,a lowered position to permit visibility of a line being printed when no printingsignal is being applied, and is selectively 1 raised to the printing position when printingaction is required.

In such high-speed printers, particularly the type employing a plurality of discrete printing hammers, the printingribbon must extend unsupported across the length-ofthe writing area,

generally a distance of about 17 to 20 inches, and must alsobe readily replaceable by an operator of the equipment. These requirements dictate that ribbon spools andguides be provided'cat accessible locations on the sides of the high-speed "printer in such a manner that theunsupported ribbon is maintainedwunder tension across the entire extent of the writing area in order that the-ribbon may beraised-andlowered as a relatively rigid beam. It is alsonece ssary that the ribbon .drive mechanismhave-automatic reversing capability.

The nature of the highspeed printer, due to its high speed of operation, precludes incremental movement of1the ribbon in the manner-employed in conventional :typewriters whereby 'ribbon indexingis accomplished as a byproduct of type-bar motion through mechanical association. Hence, the drive mechanisms for the ribbon spoolers on which the-printing ribbonispaidout and taken up must tensionythe ribbon, 'be

located for ready replaceability by'the operator onthe sides of the machine, be-automaticallyreversing and-mustbe independentlyidrivenata low speed; Reliabilityin operation,-further requires that the reversing and tensioning spool drive mechanism be-essentially jam-proof to :avoid ,or minimize mechanical-breakdown. Further, dueto thefact that the inked ribbon must be raised very 'rapidlyfrom the viewing togthe printing" position and then returned,-it is imperative thatthe tensioning of the ribbon be accomplished in such .a- -manner that-the tensioned ribbon does not contribute or add to the inertial force required of theribbon lifting arms.

5 SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a newand improved high-,speedprinter of the itype having an inked, :tensioned ribbonthat is 'reversiblytraversed, across a .printing area and that is:selectively moved ,upand'down to. permit character impression andsubsequentvisibility of the character formed, and wherein thewtensioned ribbon .is

. neutrally related to the ribbon lift arm insuchamannerthat the ribbon tension does not'adversely influence the ribbon lift arm torque Another object of the invention is the-provisionofa compact, simplified, preassembled ribbon-tensioning and: reversing spool drive mechanism. which is jam-proof andautomatically reversing, and which. does not contribute. to the. inertia or torque of the-associated ribbonlift arm. ln practicing the invention, a high-speed-printer is provided whichutilizes an inked ribbon traversingacross azprinting area with the inked ribbon being-selectively raisedand'loweredto permit character impressionand subsequent visibility. of the vided on each side of the printing area and firstribbon guides are mounted adjacent the end of eachpivoted cantilever arm. The printing ribbon is supported under tension between the two guides across the width of the printing area, andpivoting means are provided for pivoting the cantilever arms in unison about a common pivot axiswhereby the printing ribbon is selectively moved as a relatively rigid beam between the, printing and viewing positions by pivotal movement of the .cantilever arms. A second ribbon guide is mounted on each side of the high-speed printer for supporting the ribbon at the points intermediate the ribbon takeup and payout spools and the respective first ribbon guides. .Each secondribbon guide is mounted with its peripheral surface supporting the .ribbon in axial alignment with the pivot axis of the pivoted cantilever arm, and the ribbon is twisted through substantially a right angle in the space betweeneach second ribbon guide and its respective first ribbon guide so that it extends along a path that bisects the angleof movement of the pivoted cantilever arms. I

Nonjamming, reversible, tensioning ribbon spool drive mechanisms are supported on opposite sides of-the high-speed printer-formovingthe ribbon in either directionbetween the pair of ribbon takeup and payout spools undersubstantially constant tension and at some predetermined .low speed. The

spool drive mechanisms areselectively operable alternately to cause the spools to take up or pay out ribbon. Each of the spool drive mechanismscomprise a rotatable supporting plate having driving and neutral freewheeling positions. Amovable centercluster of gears and a ratchet is supported on the .supporting plate and coacts with fixed center gears under conditions where therotatable supporting plate is inits drivingposition. A spool supporting spindle meshes withand is rotated by the fixed center geararrangement, and includes an actuating finger which is released upon exhaustion of ribbon from the spool. This only occurs when the rotatable supporting plate is inits neutral freewheeling position and the-spool .is operating ,as a payout spool. lnterposer levermeans are provided which areactuated by the actuating finger upon the .ribbonon the spool being exhausted."The interposer.levenmeanscoactswith the ratchet torotate the rotatable supporting .plate from its neutral freewheelingposition into ,its driving position and thereby automatically reverses the operation of ,thmspool drive mechanism. A rotatable shaft is providedwhichjnterconnects the ribbon spool drivemechanism von :both sidespf the high-speed printenand connecting links interconnect the respective rotatable supporting plate of v each ,spopl. ,d,iji ve mechanismwith respective ends of the-rotatable shaft. result, rotation of zone =rof the supporting plates from, neutralfreewheeling .position, to thedriving,positionautomaticallyresults: in rotation of the opposite supporting; plate t'ro m the driving-position to the neutral freewheelingposition.

Otherobjects, features and many .of the 'attendant d with the-accompanying drawings,-wherein likerpar p the several FIGS. are identified by {the same refe r ce character, and-.wherein:

FIG. 1 is a partiallybroken-away perspective viewpf qr lttghspeed-printerconstructed in accordance withthe invention;

FIG; 2 is a sideview of the high-speed printer shownjn ElG. l, and illustrates certain details of the constructionpf the nonjamming, reversible, tensioning ribbon;spooldrive rnechanism comprising apart of the invention; and

FIG. 3 is a partial sectional .view of the, spool ,driye mechanism shown in'FlG. 2 taken throughplane DETAILED DESCRIPTION OF THE PREFERRED EMBODlMENT F l6. 1, is a partially disassembled, aperspectivayiew ;Of, a high-speed ,printer constructed in accordance ,with thetinvencharacter formed. A pairof pivoted cantilever arms are protion. The high-speed printer shown-in FlG. l,-utilizes an inked printing ribbon 11 that is traversed back and forth across a printing area generally defined by a cylindrical platen 12. Ribbon 11 is selectively raised and lowered by a pair of cantilever arms 13 and 14 to permit character impression and subsequent visibility of the character formed by a suitable lift arm mechanism (not show.) for pivotally moving the cantilever arms 13 and 14 up and down to selectively place ribbon 11 in printing position adjacent the platen 12. The lift arm mechanism does not comprise a part of the instant invention but is described more fully in my copending US. application Ser. No. 734,469 entitled High-Speed Printer Having Controlled Acceleration Ribbon Positioning Differential Mechanism," filed concurrently herewith. The ribbon 11 is supported at the end of the cantilever arms 13 and 14 by a first pair of vertically disposed guides 15 and 16 between which the ribbon 11 is extended and tensioned so that in effect it can be moved up and down as a relatively rigid beam by the cantilever arms 13 and 14. The arrangement is such that with the cantilever arm and hence ribbon 11 in the lowered position, the printed characters formed on a recording medium 1 disposed over platen 12, can be viewed, and the ribbon 11 must be raised by the cantilever arms 13 and 14 to place the ribbon in printing position.

With the ribbon 11 in printing position, a high-speed rotating belt of flexible fingers (not shown) rotates the several printing fingers past the printing area formed by the surface of platen 12 along a line spaced outwardly from ribbon 11 with respect to platen 12. The printing fingers each have a known character such as one of the letters of the alphabet, punctuation mark, number, etc., formed thereon which are scanned past the front of the ribbon 11 at a known rate. At an appropriate point along the printing area where it is desired to form one of the characters on the recording medium disposed over platen 12, a selectively operated hammer (not shown) is actuated to cause the desired printing finger to be pressed against the recording medium by way of the inked ribbon 11. The result is to form an inked impression of the character appearing on the selected printing finger which was hit by the hammer. The details of construction of the rotating belt of printing fingers and the printing hammer together with required synchronizing circuitry to assure proper operation of the printer, do not comprise a part of the instant invention and are not shown. It might be noted, however, that the invention herein described need not necessarily be employed in conjunction with a high-speed printing arrangement utilizing separate printing fingers and printing hammers, but could also be employed with separately actuated hammers having desired characters formed on their face similar to the arrangement used in conventional typewriters, etc.

It will be appreciated from the foregoing description, that with a high-speed printer of the type envisioned in FIG. 1, the printing ribbon 11 must extend unsupported across the length of the writing area which may be a distance on the order of 17 to inches, and must also be readily replaceable by an operator of the equipment. These requirements dictate that the ribbon 11 be maintained under tension so that it provides rigidity to the unsupported ribbon section extending between the guides 15 and 16. It is also essential that the tensioned ribbon not contribute to or add to the initial force or torque required to lift the cantilever arms 13 and 14. To overcome this problem, the ribbon 11 is twisted through substantially a right angle as shown at 17 and passed over a set of second ribbon guides, one of which is shown at 18, mounted on each side of the high-speed printer. The second guides 18 support ribbon 11 at points intermediate the ribbon takeup and payout spools one of which is shown at 19 and the respective first ribbon guide, such as 15. As is best shown in H6. 2 of the drawings, each of the second ribbon guides 18 are mounted in such a manner that their peripheral surface which supports ribbon 11 is in axial alignment with the pivot axis of the pivoted cantilever arms 13 and 14. Additionally, ribbon 11 is twisted through substantially a right angle in the space between the second ribbon guide 18 and its respective first ribbon guide such as 15, and is caused to extend along a path that bisects the angular movement of the pivoted cantilever arms 13 and 14 as is best illustrated in FIG. 2. By reason of this arrangement, the tensioned ribbon will cause little, if any, additional loading or torque on the cantilever arm raising and lowering mechanism.

In order to provide a proper tension to the ribbon 11 and to cause it to be reversibly moved across the printing area, nonjamming, reversible, tensioning ribbon spool drive mechanisms, one of which is indicated generally at 21, are provided and are supported on opposite sides of the highspeed printer for moving the ribbon 11 under tension in either direction between the ribbon takeup and payout spools 19. The spool drive mechanisms 21 are selectively operable alternately to cause the spools 19 to take up or ay out ribbon, and are shown in greater detail in FIGS. 2 and 3 of the drawings. As is best shown in H6. 2 of the drawings, each of the spool drive mechanisms 21 comprise a rotatable supporting plate 22 having driving and neutral freewheeling positions illustrated by solid and dotted lines, respectively. The rotatable supporting plate 22 is pivoted at 23 and suppons a movable centercluster of gears and a ratchet which coact with first pinion gear 24 centered at the pivot point 23 and rotated by a suitable drive shaft coupling 25 (shown in FIG. 3) that in turn is driven by a constant speed jack shaft to which the coupling 25 is secured. The cluster of movable center gears and ratchet is comprised by a first driven gear 26 that meshes with and is driven by the first pinion gear 24. The first driven gear 26 is clustered with a second pinion gear 27 and a ratchet 28, all of which are rotated in unison about a common center 29D secured to and movable with a rotatable plate 22. The arrangement is such that the first driven gear 26 is rotatably movable in an are between a driving position of the rotatable plate 22 and a neutral freewheeling position for the rotatable plate 22 (shown in dotted outline form) in a manner which permits continuous meshing of the first driven gear 26 with the first pinion gear 24.

With the rotatable plate 22 in its driving position shown in solid line, the second pinion gear 27 meshes with and drives an intermediate driven gear 31 that is clustered and rotates in synchronism with a third pinion gear 32. The third pinion gear 32 meshes with and either drives or is driven by an output gear 33 which is clustered and rotates in synchronism with a spindle 34 to which the ribbon spool 19 is secured by means of a clip spring 35 as best seen in F10. 03 of the drawings.

in operation, assuming that the rotatable plate 22 is in its driving position as shown in solid line in H0. 2, then the spool drive mechanism 21 on the left-hand side of the high-speed printer will operate in the following manner. As will be described more fully hereinafter, the spool drive mechanism 21 on the opposite or right side of the high-speed printer, will have its rotatable plate 22 in the neutral freewheeling position, and hence will function as the payout spool. The spool 19 shown in FIG. 2 for the purpose of the following description will be assumed to be the takeup spool. The jack shaft to which coupling 25, as shown in FIG. 3, and hence pinion 24 is secured is assumed to be constantly rotating in a clockwise direction as shown in FIG. 2. Pinion 24 is constantly meshing with the first drive gear 26 which rotates about the center 29 in synchronism with the second pinion 27 and ratchet 28. Since it has been assumed that plate 22 is in the driving position, pinion 27 will mesh with and drive the intermediate driven gear 31. This results in rotating third pinion 32 in synchronism with the rotation of intermediate driven gear 31 and consequently will result in rotating output gear 33. Rotation of output gear 33 results in rotation of the spool spindle 34 so as a consequence the ribbon spool 19 will function to take up ribbon 11.

In order to tension the ribbon ll properly while it is traversed across the printing area in the above briefly described fashion, the spool spindle 34 is designed to be resiliently rotatable relative to the output gear 33 by reason of a combined compression and torsion spring 41, as shown in g f h HG. 3, supported within the core of spindle 34. The spring 41 is compressed between the hub of spindle 34 and output gear 33 as best shown in FIG. 3 of the drawings, and serves to press output gear 33 against the supporting plate 42' comprising a part of the chassis ,of the ribbon drive. As a result, tensionirig of theribbon 11 is act mplished by the frictional drag of output gear 33 against the supporting plate 42 by reason of the compressive urging of the spring 41. Hence, it will be appreciated that whichever one of the two spools 19 is operating as the payout spool, this frictional dr'ag will serve to tension the ribbon 11 a predetermined amount in a desired fashion.

In addition to being compressed, the spring 41 also is preloaded torsionaily between the output gear 33 and the spindle 34. Upon the. ribbon spool 'l9being placed upon spindle in the manner best shown in FIG. 3, it is retained in place by the clip 35. Assuming now that the spool is operating as a payout spool, as the ribbon 11 commences to unwind,the spring 41 is abutment 47 of interposer lever 45 is physically disengaged by subjected'to additional torsional deflection due to'the factthat the spindle'34 is allowed to'r'otate' relative to output gear 33 for a predetermined angulandistance, approximately 60", at the end of which the spindle 34 and-output gear 33 commence to rotate as a unit when the lugon 34 reaches the end of the slot on 33. This relative rotation is made possible by appropriate design of the torsional characteristics of the spring '41 so that the compression due to the spring causes the frictional torque of gear 33 to exceed the wound torque of the same spring. The resiliency. of spindle 34 relative to output gear 33 thus provides a slack 'takeup characteristic for the purpose of preventing instantaneous slackening of the ribbon 11 (particularly during reversing) while the frictional dragof the output gear 33 limits the ribbon tension. i

For the purpose of the following description, now it will be assumed that the spool drive mechanism 21 shown-in FIG. 2 has its rotatable plate 22 rotated to the neutral freewheeling position shown in dotted lines and that the spool 19' is being operatedas a payout spool. Under these conditions, it will be appreciated therefore "that thesecond pinion gear 27 will be rotated toits dotted'line position, and hence is out of mesh with the intermediate driven gear-31. As a consequence, the ribbon spool 19, its, spindle 34; output gear 33,-third pinion 32, and the intermediate driven. gear 31, are all free to rotate in a direction reverse to that previously assumed so that the tape 11 can be moved in a payout direction. Under these assumed conditions, the ribbon 11 on. spool 19 will eventually be exhausted or completely unwound therefrom.

The spindle 34 is designed so that it includes a ribbonsensor 411s shown in Fl GSQ2'and 3, which'is pivotallyand resiliently. mounted within the spindle 34 by means of a pivot 49 anda spring 4,8..The spool l9 is designed to include a slot through which the finger or ribbon sensor 43 is free to emerge upon the ribbon 11 being completely unwound from the spool. Upon this occurrence, the finger 43 will move outwardly to the position shown in FIG. 3.

As'the spool 19 continues to unwind, the sensing finger 43 moves from a position shown at 43A where it emerged in FIG. 2 to the position shown at 438. At position 438, the sensing finger comes into contact with one end 44 of an elongated interposer lever 45 pivotally supported on the mounting plate 42 v at 46. Upon end 44 of interposer lever 45 being engaged by the emerged sensing finger 43, interposer lever 45 pivots so as .to place an abutment 47 formed on its opposite end into the periphery of the rotating ratchet 28. As a result, a tooth of the ratchet 28 becomes interposed, causing the rotatable supporting plate22 to be pivoted about point 23 through the action of the continuously rotating pinion 24 that continues to drive gear 26and hence ratchet 28 in a counterclockwise direction as shown in FIG. 2. The result is to rotate supporting plate 22 into its driving position so that the second pinion gear 27 is causedto mesh with. androtate the intermediate driven gear 31.

After the rotatable plate 22 has rotated through approximately two thirds of the distance between its neutral freewheeling position and itsdriving position, the interposed the following edge of the tooth of the ratchet wheel 28 acting against the inner portion of the interposer lever arm on which abutment 47 is formed. To assure that the rotatable plate 22 continues its motion into the driving position and is held there, an overcenter spring 51 is provided which urges the rotatable plate the remainder of the distance into the driving position and maintains it there. Upon being subsequently switched to its neutral freewheeling position, as will be described more fully hereinafter, the overcenter spring 51 will serve to maintain the plate in the neutral freewheeling position.

In order to reverse the position of the rotatable plate on the opposite spool drive mechanism which previously'had been in the driving position, a connecting link 52 is connected between one end 53 of movable plate 22 and a crank arm 54L that is secured to and rotates a rotatable shaft 55. The rotataplate 22 to its neutral freewheeling position. Hence, it will be appreciated that it is impossible for both plates to be simultaneously in the driving position, and hence nonjamming of the apparatus is guaranteed. Reversal of, the supporting plates in the above manner, automatically will bring about a reversal in'the direction of travel of ribbon ll acrossthe printing area of the high-speed printer.

From the foregoing description, it will be appreciated that the present invention makes available a new and improved high-speed printer of the type having an inked,tensioned ribbon that is reversibly traversed across a printing area, and that is selectively moved up and down to permit character impression and subsequent visibility of the character formed, and wherein the tensioned ribbon is neutrally related to the ribbon lift arm mechanisms in such a manner that the ribbon tension does not adversely influence-the lift arm torque. The invention also makes available a compact, simplified,,preassembled ribbon tensioning and reversing spool drive mechanism which is jam-proof and automatically reversing, and'which does not contribute to the inertia or torque of the associated ribbon lift arm mechanism.

Having described a preferred embodiment of a high-speed printer having an improved ribbon tensioning and reversing drive mechanism, it is believed obvious that other modifications and variations of the invention are possible in the light of the above teachings. It is therefore to be understood that changes may be made in the particular embodiment of the vention described which are within the full intended scope of the invention as defined by the appended claims.

I claim:

1. A nonjamming, reversible, tensioning ribbon spool drive mechanism for moving a ribbon in either direction en a pair of ribbon spools supported on opposite s ides ofa ork area under substantially constant tension and at i predetennined speed, said drive mechanism being opera temately to cause its spool to take up or pay out n and comprising first pinion gear means secured to and rotatedv by suitable drive shaft means, first driven gear mean with and driven by said first pinion gear means, porting plate means having said first driven ns rotatably supported thereon and rotatably .movahl i an .e between a driving position and a neutral freewheeling n in a manner which permits continuous meshing of. first driven gear means with thefirst pinion gear means, a het wheel means and second pinion gear means rotatably sup.- ported on said rotatable supporting plate and rotated in synchronism with said first driven gear means, intermediate driven gear means for meshing with and rotation by said second pinion gear means upon Said rotatable supporting plate being rotated to the drivingposition third pinion. gear means rotated by said intemiediate driven gear means, output gear means meshing with and driven by said third pinion gear means, spindle means for supporting a ribbon spool rotated by said output gear means, said spindle means including spring loaded finger means held in a depressed position by a ribbon spool having ribbon wound thereon, the ribbon spool having a slot therein for emergznce of said finger means upon the ribbon being completely unwound therefrom under conditions where the spool is operated to pay out ribbon and the rotatable supporting plate means associated therewith is in the neutral freewheeling position, and pivoted lever means having one end engaged by said finger means in the emerged position, the remaining end of said pivoted lever means engaging said ratchet wheel upon the lever means being pivoted by the finger means and serving to rotate the rotatable supporting plate means from the neutral freewheeling position to the driving position whereby said second pinion gear means, which is maintained out of engagement with said intermediate driven gear means with the rotatable supporting plate means in the neutral freewheeling position, is brought into engagement with said intermediate driven gear means to thereby reverse the action of the spool and cause it to take up ribbon.

2. A ribbon spool drive according to claim 1 further including overcenter spring means connected to each of said rotatable supporting plate means for holding the supporting plate means in either the driving or neutral freewheeling position.

3. A ribbon spool drive according to claim 2 further including rotatable shaft means interconnecting the ribbon spool drive mechanisms on opposite sides of the work area and respective connecting link means interconnecting the respective rotatable supporting plate means of each spool drive mechanism to respective ends of the rotatable shaft means in a manner such that rotation of one of the supporting plate means from the neutral freewheeling position to the driving position results in rotation of the opposite supporting plate means from the driving position to the neutral freewheeling position.

4. A ribbon spool drive according to claim 3 further including compression spring means for forcing the output gear means into frictional engagement with a supporting member for creating frictional drag that serves to tension the ribbon.

5. A ribbon spool drive according to claim 4 wherein said compression spring means also comprises a torsion spring and is supported within said spindle means, and said spindle means is coupled to the output drive gear means at least in part through the medium of said combined compression and torsional spring means, said spindle means being relatively rotatable a predetermined amount with respect to the output gear drive means for torsionally preloading the spring means prior to said spindle means and output drive gear means rotating as a unit to thereby provide resiliency to the spindle means relative to the output drive gear means and prevent instantaneous slackening of the ribbon.

6. A nonjamming, reversible, tensioning ribbon spool drive mechanism for moving a ribbon under substantially constant tension and at some predetermined speed, in either direction between a pair of ribbon spools supported on opposite sides of an intermediate space, said drive mechanism being selectively operable alternately to cause its spool to take up or pay out ribbon, said spool drive mechanism comprising rotatable supporting plate means having driving and neutral freewheeling positions, movable center gear and ratchet means supported on said supporting plate means, fixed center gear means coacting with said movable center gear means with the rotatable supporting plate in the driving position, spindle means for supporting the ribbon spool and rotatable by said fixed center gear means, said spindle means including finger means actuable by the exhaustion of ribbon from a spool supported thereon where the rotatable supporting plate is in the freewheeling position and the spool is operating as a payout spool, and interposer lever means actuable by said finger means upon the ribbon on a spool being exhausted, said interposer lever means coacting with the ratchet means to rotate the rotatable supporting plate means from its neutral freewheeling position into its driving position thereby reversing the operation of the spool.

7. A ribbon spool drive according to claim 6 further including overcenter spring means connected to each of said rotatable supporting plate means for holding the supporting plate means in either the driving or neutral freewheeling position.

8. A ribbon spool drive according to claim 7 further including rotatable shaft means interconnecting the ribbon spool drive mechanisms on opposite sides of the work area and respective connecting link means interconnecting the respective rotatable supporting plate means of each spool drive mechanism to respective ends of the rotatable shaft means in a manner such that rotation of one of the supporting plate means for the neutral freewheeling position to the driving position results in rotation of the opposite supporting plate means from the driving position to the neutral freewheeling position.

9. A ribbon spool drive according to claim 8 further including compression spring means for forcing the output gear means into frictional engagement with a supporting member for creating frictional drag that serves to tension the ribbon.

10. A ribbon spool drive according to claim 9 wherein said compression spring means also comprises a torsion spring and is supported within said spindle means and said spindle means is coupled to the output drive gear means at least in part through the medium of said combined compression and torsional spring means, said spindle means being relatively rotatable a predetermined amount with respect to the output gear drive means for torsionally preloading the spring means prior to said spindle means and output drive gear means rotating as a unit to thereby provide resiliency to the spindle means relative to the output drive gear means and prevent instantaneous slackening of the ribbon.

11. In a high-speed printer including an inked ribbon traversing across a printing area and which is selectively movable to permit character impression and subsequent visibility of the character formed, a pair of pivoted cantilever arms, one mounted on each side of the printing area, a first ribbon guide mounted adjacent the end of each pivoted cantil ever arm, the ribbon being supported under tension between the two guides across the width of the printing area, and pivoting means for pivoting the cantilever arms in unison about a common pivot axis whereby the printing ribbon is selectively moved as a relatively rigid beam between the printing and viewing positions by pivotal movement of the cantilever arms, the improvement comprising a second ribbon guide mounted on each side of the high-speed printer for supporting the ribbon at points intermediate ribbon takeup and payout spools and the respective first ribbon guides, each second ribbon guide being mounted with the peripheral surface thereof supporting the ribbon in axial alignment with the pivot axis of the pivoted cantilever arms, the ribbon being twisted through substantially a right angle in the space between each second ribbon guide and its respective first ribbon guide and extending along a path that bisects the angle of movement of the pivoted cantilever arms, said high-speed printer further including nonjamming, reversible, tensioning ribbon spool drive mechanisms supported on opposite sides of the high-speed printer for moving the ribbon in either direction between the pair of ribbon takeup and payout spools under substantially constant tension and at some predetermined speed, said spool drive mechanisms being selectively operable alternately to cause the spools to take up or pay out ribbon, each of said spool drive mechanisms comprising rotatable supporting plate means having driving and neutral freewheeling positions, movable center gear and ratchet means supported on said supporting plate means, fixed center gear means coacting with said movable center gear means with the rotatable supporting plate in the driving position, spindle means for supporting the ribbon spool and rotatable by said fixed center gear means, said spindle means including finger means actuable by the exhaustion of ribbon from a spool supported thereon where the rotatable supporting plate is in the freewheeling position and the spool is operating as a payout spool, and interposer lever means actuable by said fingerrneans upon the ribbon on a spool being exhausted, said interposer lever means coacting with the ratchet means to rotate the rotatable supportingplate means from its neutral freewheeling position into its driving position thereby reversing the operation of the spool.

12. A high-speed printer according to claim 11 further including rotatable shaft means interconnecting the ribbon spool drive mechanisms on opposite sides of the printer and respective connecting link means interconnecting the respective'rotatable supporting plate means of each spool drive mechanism to respective ends of the rotatable shaft means in a manner such that rotation of one of the supporting plate means from the neutral freewheeling position to the driving position results in rotation of the opposite supporting plate means from the driving position to the neutral freewheeling position.

13. A high-speed printer according to claim 11 further including nonjamming, reversible, tensioning ribbon spool drive mechanisms supported on opposite sides of the printer for moving a ribbon in either direction between the pair of ribbon takeup and payout spools under substantially constant tension and at some predetermined speed, each of said drive mechanisms being operable alternately to cause the spools to take up or pay out ribbon and comprising first pinion gear means secured to and rotated by suitable drive shaft means, first driven gear means meshing with and driven by said first pinion gear means, rotatable supporting plate means having said first driven gear means rotatably supported thereon and rotatably movable in an are between a driving position and a neutral freewheeling position in a manner which permits continuous meshing of said first driven gear means with the first pinion gear means, ratchet wheel means and second pinion gear means rotatably supported on said rotatable supporting plate and rotated in synchronism with said first driven gear means, intermediate driven gear means for meshing with and rotation by said second pinion gear means with said rotatable supporting plate rotated to the driving position, third pinion gear means rotated by said intermediate driven gear means, output gear means meshing with and driven by said third pinion gear means, spindle means for supporting a ribbon spool rotated by saidoutput gear means, said spindle means including spring loaded finger means held in a depressed position by a ribbon spool having ribbon wound thereon, the ribbon spool having a slot therein for emergence of said finger means upon the ribbon being completely unwound therefrom under conditions where the spool is operated to pay out ribbon and the rotatable supporting plate means associated therewith is in the neutral freewheeling position, and pivoted lever means having one end engaged by said finger means in the emerged position, the remaining end of said pivoted lever means engaging said ratchet wheel upon the lever means being pivoted by the finger means and serving to rotate the rotatable supporting plate means from the neutral freewheeling position to thedriving position whereby said second pinion gear means which previously had been maintained out of engagement with said intermediate driven gear means while the rotatable supporting plate means was in the neutral freewheeling position is brought into engagement with said intermediate driven gear means to thereby reverse the action of the spool and cause it to take up ribbon.

14. A high-speed printer according to claim 13 further ineluding overcenter spring means connected to each of said rotatable supporting plate means for holding the supporting plate means in either the driving or neutral freewheeling posi tion.

15, A high-speed printer according to claim 14 further including rotatable shaft vmeans interconnecting the ribbon spool drive mechanisms on opposite sides of the printer and respective connecting link means interconnecting the respective rotatable supporting plate means of each spool drive mechanism to respective ends of the rotatable shaft means in a manner such that rotation of one of the supporting plate means from the neutral freewheeling position to the driving position results in rotation of the opposite supporting plate means from the driving position to the neutral freewheeling position.

16. A high-speed printer according to claim 15 further including compression spring means for forcing the output gear means into frictional engagement with asupporting member for creating frictional drag tat serves to tension the ribbon.

17. A high-speed print er according to claim 16 wherein said compression spring means also comprises a torsion spring and is supported within said spindle means, and said spindle means is coupled to the output drive gear means at least in part through the medium of said combined compression and torsional spring means, said spindle means being relatively rotatable a predetermined amount with respect to the output drive gear means for torsionally preloading the spring means prior to said spindle means and output drive gear means rotating as a unit to thereby provide resiliency to the spindle means relative to the output drive gear means and prevent instantaneous slackening of the ribbon.

Claims

1. A nonjamming, reversible, tensioning ribbon spool drive mechanism for moving a ribbon in either direction between a pair of ribbon spools supported on opposite sides of a work area under substantially constant tension and at some predetermined speed, said drive mechanism being operable alternately to cause its spool to take up or pay out ribbon and comprising first pinion gear means secured to and rotated by suitable drive shaft means, first driven gear means meshing with and driven by said first pinion gear means, rotatable supporting plate means having said first driven gear means rotatably supported thereon and rotatably movable in an arc between a driving position and a neutral freewheeling position in a manner which permits continuous meshing of said first driven gear means with the first pinion gear means, ratchet wheel means and second pinion gear means rotatably supported on said rotatable supporting plate and rotated in synchronism with said first driven gear means, intermediate driven gear means for meshing with and rotation by said second pinion gear means upon said rotatable supporting plate being rotated to the driving position third pinion gear means rotated by said intermediate driven gear means, output gear means meshing with and driven by said third pinion gear means, spindle means for supporting a ribbon spool rotated by said output gear means, said spindle means including spring loaded finger means held in a depressed position by a ribbon spool having ribbon wound thereon, the ribbon spool having a slot therein for emergence of said finger means upon the ribbon being completely unwound therefrom under conditions where the spool is operated to pay out ribbon and the rotatable supporting plate means associated therewith is in the neutral freewheeling position, and pivoted lever means having one end engaged by said finger means in the emerged position, the remaining end of said pivoted lever means engaging said ratchet wheel upon the lever means being pivoted by the finger means and serving to rotate the rotatable supporting plate means from the neutral freewheeling position to the driving position whereby said second pinion gear means, which is maintained out of engagement with said intermediate driven gear means with the rotatable supporting plate means in the neutral freewheeling position, is brought into engagement with said intermediate driven gear means to thereby reverse the action of the spool and cause it to take up ribbon.

11. In a high-speed printer including an inked ribbon traversing across a printing area and which is selectively movable to permit character impression and subsequent visibility of the character formed, a pair of pivoted cantilever arms, one mounted on each side of the printing area, a first ribbon guide mounted adjacent the end of each pivoted cantilever arm, the ribbon being supported under tension between the two guides across the width of the printing area, and pivoting means for pivoting the cantilever arms in unison about a commOn pivot axis whereby the printing ribbon is selectively moved as a relatively rigid beam between the printing and viewing positions by pivotal movement of the cantilever arms, the improvement comprising a second ribbon guide mounted on each side of the high-speed printer for supporting the ribbon at points intermediate ribbon takeup and payout spools and the respective first ribbon guides, each second ribbon guide being mounted with the peripheral surface thereof supporting the ribbon in axial alignment with the pivot axis of the pivoted cantilever arms, the ribbon being twisted through substantially a right angle in the space between each second ribbon guide and its respective first ribbon guide and extending along a path that bisects the angle of movement of the pivoted cantilever arms, said high-speed printer further including nonjamming, reversible, tensioning ribbon spool drive mechanisms supported on opposite sides of the high-speed printer for moving the ribbon in either direction between the pair of ribbon takeup and payout spools under substantially constant tension and at some predetermined speed, said spool drive mechanisms being selectively operable alternately to cause the spools to take up or pay out ribbon, each of said spool drive mechanisms comprising rotatable supporting plate means having driving and neutral freewheeling positions, movable center gear and ratchet means supported on said supporting plate means, fixed center gear means coacting with said movable center gear means with the rotatable supporting plate in the driving position, spindle means for supporting the ribbon spool and rotatable by said fixed center gear means, said spindle means including finger means actuable by the exhaustion of ribbon from a spool supported thereon where the rotatable supporting plate is in the freewheeling position and the spool is operating as a payout spool, and interposer lever means actuable by said finger means upon the ribbon on a spool being exhausted, said interposer lever means coacting with the ratchet means to rotate the rotatable supporting plate means from its neutral freewheeling position into its driving position thereby reversing the operation of the spool.

12. A high-speed printer according to claim 11 further including rotatable shaft means interconnecting the ribbon spool drive mechanisms on opposite sides of the printer and respective connecting link means interconnecting the respective rotatable supporting plate means of each spool drive mechanism to respective ends of the rotatable shaft means in a manner such that rotation of one of the supporting plate means from the neutral freewheeling position to the driving position results in rotation of the opposite supporting plate means from the driving position to the neutral freewheeling position.

13. A high-speed printer according to claim 11 further including nonjamming, reversible, tensioning ribbon spool drive mechanisms supported on opposite sides of the printer for moving a ribbon in either direction between the pair of ribbon takeup and payout spools under substantially constant tension and at some predetermined speed, each of said drive mechanisms being operable alternately to cause the spools to take up or pay out ribbon and comprising first pinion gear means secured to and rotated by suitable drive shaft means, first driven gear means meshing with and driven by said first pinion gear means, rotatable supporting plate means having said first driven gear means rotatably supported thereon and rotatably movable in an arc between a driving position and a neutral freewheeling position in a manner which permits continuous meshing of said first driven gear means with the first pinion gear means, ratchet wheel means and second pinion gear means rotatably supported on said rotatable supporting plate and rotated in synchronism with said first driven gear means, intermediate driven gear means for meshing with and rotation by said second pinion gear means with said rotatable supporting plate rotaTed to the driving position, third pinion gear means rotated by said intermediate driven gear means, output gear means meshing with and driven by said third pinion gear means, spindle means for supporting a ribbon spool rotated by said output gear means, said spindle means including spring loaded finger means held in a depressed position by a ribbon spool having ribbon wound thereon, the ribbon spool having a slot therein for emergence of said finger means upon the ribbon being completely unwound therefrom under conditions where the spool is operated to pay out ribbon and the rotatable supporting plate means associated therewith is in the neutral freewheeling position, and pivoted lever means having one end engaged by said finger means in the emerged position, the remaining end of said pivoted lever means engaging said ratchet wheel upon the lever means being pivoted by the finger means and serving to rotate the rotatable supporting plate means from the neutral freewheeling position to the driving position whereby said second pinion gear means which previously had been maintained out of engagement with said intermediate driven gear means while the rotatable supporting plate means was in the neutral freewheeling position is brought into engagement with said intermediate driven gear means to thereby reverse the action of the spool and cause it to take up ribbon.

14. A high-speed printer according to claim 13 further including overcenter spring means connected to each of said rotatable supporting plate means for holding the supporting plate means in either the driving or neutral freewheeling position.

15. A high-speed printer according to claim 14 further including rotatable shaft means interconnecting the ribbon spool drive mechanisms on opposite sides of the printer and respective connecting link means interconnecting the respective rotatable supporting plate means of each spool drive mechanism to respective ends of the rotatable shaft means in a manner such that rotation of one of the supporting plate means from the neutral freewheeling position to the driving position results in rotation of the opposite supporting plate means from the driving position to the neutral freewheeling position.

16. A high-speed printer according to claim 15 further including compression spring means for forcing the output gear means into frictional engagement with a supporting member for creating frictional drag tat serves to tension the ribbon.

17. A high-speed printer according to claim 16 wherein said compression spring means also comprises a torsion spring and is supported within said spindle means, and said spindle means is coupled to the output drive gear means at least in part through the medium of said combined compression and torsional spring means, said spindle means being relatively rotatable a predetermined amount with respect to the output drive gear means for torsionally preloading the spring means prior to said spindle means and output drive gear means rotating as a unit to thereby provide resiliency to the spindle means relative to the output drive gear means and prevent instantaneous slackening of the ribbon.