US3014571A - Ribbon drive reversing mechanism for keyboard operated impression machines - Google Patents

Description

Dec. 26, 1961 A. PATEIMAN 3,014,571

RIBBON, DRIVE REVERSING MECHANISM FOR KEYBOARD OPERATED IMPRESSION MACHINES Filed June 5, 1959 4 Sheets-Sheet 1 INVENTOR ARTHUR PATEMAN w wm ATTORNEYS Dec. 26, 1961 A. PATEMAN 3,014,571

RIBBON DRIVE REVERSING MECHANISM FOR KEYBOARD OPERATED IMPRESSION MACHINES Filed June 5, 1959 4 Sheets-Sheet 2 INVENTOR ARTHUR PATE/VIAN ATTORNEYS Deb. 26, 1961 A. PATEMAN 3,014,571

RIBBON DRIVE REVERSING MECHANISM FOR KEYBOARD IMPRESSION MACHINES OPERATED 4 Sheets-Sheet 3 Filed June 5, 1959 ARTHUR p/a f/ m /i iv y WM ATTORNEYS Dec. 26, 1961 A. PATEMAN 3,014,571

RIBBON DRIVE REVERSING MECHANISM FOR KEYBOARD OPERATED IMPRESSION MACHINES Filed June 5, 1959 4 Sheets-Sheet 4 INVNTOR ARTHUR PATEMAN 39 WWW ATTORNEYS States Patented Dec. 2%, i961 land Filed June 5, ESQ, Ser. No. 818,455 Claims priority, application Great Britain June 6, 1958 6 Claims. (Cl. l97-l6) This invention is for improvements in or relating to typewriting and like machines, which expression is intended to include in addition to typewriters, other keyboard operated machines in which a type impression is made through a ribbon, such as adding and accounting machines. The invention has for one of its objects to provide an improved controlling means for reversal'of ribbon actuation in such machines.

In typewriting and like machines, the ribbon by which the first or top type impression is made is advanced step by step between spools at opposite sides of the typing station so that different parts of the ribbon are used for successive type impressions in order to maintain substantial uniformity of clearness of the impressions, the ribbon movement being reversed periodically so that the exhaustion of the ink or the like on the ribbon occurs substantially uniformly throughout its length. The reversal of ribbon feed occurs as soon as one spool has been substantially emptied and the other is correspondingly full, but as the ends of the ribbon are attached to the two spools, a length of unused ribbon necessarily extends at each end from the appropriate spool to the typing station. Unless reversal of the ribbon feed occurs accurately when the same portions of the ribbon are at the typing station, there is a liability for unequal typing impressions to occur round about the time of reversal,

and it is found that known forms of reversal mechanism operated by feelers bearing radially inwards against the ribbon wound on the spools or by droppers which detect the unwinding of the innermost turn or" ribbon on the spools are liable to suffer from this disadvantage. The invention seeks to provide reversal mechanism which will operate accurately and promptly in such manner as to avoid the disadvantage just referred to.

In accordance with the invention there is provided in a typewriting or like machine the combination with ribbon drive mechanism and means for reversing the ribbon drive of a dropper arranged to be released by the ribbon when reversal is required, and keyboard operated means for positively actuating said reversing means in response to movement of the dropper.

Thus the dropper can be arranged to detect accurately and with regularity the position of the ribbon at which reversal is needed, and the next actuation of the keyboard immediately brings about reversal of the feed so that a substantially instantaneous reversal occurs always at the same position of the ribbon. In practice there will of course be two droppers associated respectively with the spools to which the ends of the ribbon are attached.

In a preferred construction each dropper comprises a weighted lever pivoted to a spool holder and arranged to bear outwardly against the innermost coil of the ribbon on a spool placed on such holder so that as this coil unwiuds from the spool, the dropper is released and is caused thereby to vary actuation of a lever operated from the keyboard in such manner as to efiect reversal of the ribbon feed.

A preferred form of mechanism in accordance with the invention is illustrated in the accompanying drawings in which FIGURE 1 is a plan view of those parts of a typewriter which are concerned in the ribbon mounting and feed,

FIGURE 2 is an enlarged side view of certain of the parts,

FIGURE 3 is an enlarged front view of certain details as seen in the direction of arrow A in FIG. 1,

FIGURES 4 and 5 are enlarged detail plan views corresponding to portions of FIG. 1 showing the left hand and right hand spool holders respectively, and

FEGURE 6 is an enlarged detail side view corresponding to part of FIG. 2.

For the sake of simplicity only those parts of the typewriting machine which are necessary for a proper understanding of the provisions of the invention are shown in the drawings. The mountings for the various parts shown are of orthodox construction and arrangement and do not need specific illustration or description as they will readily be understood by persons skilled in the art.

As shown in FIG. 1 the spool cups 30 at the two sides of the machine have central hollow spool spindles 31 which are adapted to be driven step by step when required from side shafts 8 geared by bevel gears 32 and 7 to a transverse shaft 6 at the back or" the machine. The shaft 6 is rotated step by step by a cup gear 5 connected by a clutch to the shaft and meshing with a small gear 4 driven by a larger spur gear 3 which in turn is driven by a pin 2 from the spring drum 1 which drives the platen carriage. Thus, at each step of movement of the carriage the drum moves a corresponding step and causes, step by step, rotation of shaft 6 and side shafts 8. Each side shaft 8 has a continuation portion 8 coupled to it by a universal joint 33, E68. 2 and 6, and the shaft portions 8 have freely rotatable on them bevel gears lil (also forming clutch parts) meshing with bevel gears 34 secured to the spindles 31. Each shaft portion 8 carries a slidable clutch member 9 keyed to rotate with it for coupling its bevel gear N to the shaft. The clutches 9 are so arranged that only one is engaged at a given time and the particular clutch engaged drives the bevel gear iii to rotate, through the corresponding bevel gear 3 the appropriate spool spindle 31. Intermittent rotation of the spool spindle serves gradually to wind the ribbon on to that spool and withdraw it from the other spool at the opposite side of the machine.

As can be seen from FIGS. 2 and 6 each spool cup 30 contains a hollow spool holder 11 secured to the end of spindle 31, and the holder ll supports within it a pivoted drop lever 21 having a tail carrying a dropper plunger 22 which is slidable within the spindle and the lower end of which is caused to project from the lower end of the spindle and its bevel gear when the lever 21 is released. Normally lever 21 is held raised by engagement with the innermost turn of ribbon wound on a slotted sleeve (not shown) mounted on holder 11. Associated with the dropper plunger 22 is a reverse operating lever 20 pivoted to a further lever 23 by a pivot screw 28 The lever 23 is provided at the left hand spool mounting as shown in FIGS. 1 and 4 and has a tail through which it is coupled by a connecting bar 24 to a similar lever 25, FIGS. 1 and 5, at the right hand spool holder and pivoted to a fixed part by a pivot screw 25 The lever 25 also carries a reverse operating lever 20 and in addition it is formed with an extension piece 25 formed with two detent recesses and an interposed hump with which there engages a spring urged roller 26 to determine two alternative settings of lever 25 and therefore of lever 23 since the two levers move in company. The reverse operating levers 2t are respectively capable of rocking movement to carry projections thereon across the line of the dropper plungers 22 and serve to detect in a manner about to be described when their respective dropper plungers have fallen.

The reverse operating levers it are arranged to be operated by keyboard action by means of side links 19 coupled between levers 2t and outward ends of levers 18 pivoted at 18 The inner parts of levers 18 are coupled to other levers on the same pivots which extend to the center of the back of the mechanism and they are engaged by a common link 17 which is operated as followsv from the keyboard. As shown most clearly in FlG. 2 the key levers one of which is shown at 12 operate a ribbon frame 13 extending across the machine and pivoted at 13* so that, when a key is depressed, link 14 coupling the ribbon frame 13 to a bell crank lever 15 is operated causing lever 15 to rock and by engagement with a roller on a roller lever in pivoted at 16 causes rocking movement of the latter. The link 17 is anchored to one arm of the lever 16 so that on depression of a key it is moved rearwardly thereby rocking both of lovers 18 and moving side links 19 to rock the reverse operating levers 2%. If both droppers are raised the levers 2t) wili turn idly about their pivots 2th but when one dropper has fallen due to substantial emptying of its spool the corresponding lever 2%) will engage the dropper plunger and be prevented from turning further on its pivot Zit so that the further movement of link 19 is transmitted to lever 23 or 25 which is thereupon rocked on its pivot sufficiently to cause roller 26 to move over the cam hump on lever extension 25' and snap into the opposite cam recess. Thereby levers 25 and 23 are moved in company to their opposite setting and this movement is arranged to reverse engagement of the clutches Q.

The clutches 9 are operated from the levers 23 and 25 by links 27 which are each anchored at one end to the appropriate lever, and carry pins 28 on their opposite ends to engage in perpiheral grooves in the respective clutch members 9. Thus when the levers 23 and 25 are rocked one way about their pivots 23 and 25 one clutch member 9 is engaged and the other is disengaged. When the levers are rocked the other way, reverse engagement and disengagement occur.

With the arrangement described operation of any of the keys on the keyboard causes shifting of the side levers 19- and rocking of the reverse levers 29 without effect until ribbon reversal is required whereupon the ribbon spool about to become empty will release its dropper lever 23. immediate'ry the innermost coil of the ribbon or ribbon holder commences to be unwound thus allowing the corresponding dropper plunger 22 to fall into the path of the corresponding reverse lever 20. Immediately this occurs reversal of the ribbon feed will be positively effected by the next depression of a key on the keyboard. Consequently an accurate and constant gauging of the position of ribbon reversal is secured.

What I claim is:

1. In a keyboard operated ribbon impression machine, a ribbon drive reversing mechanism comprising a pair of rotatable ribbon carriers for having a ribbon extend therebetween with an end wound thereon, a drive mechanism connected to said machine for being operated there by and having oppositely rotating members, a lever mechanism operatively connected to said keyboard, clutch means operatively connected to said lever mechanism and detachably connecting each of said drive mechanism oppositely rotating members to one of said ribbon carriers for rotating said carriers, and dropper means associated with each ribbon carrier for detecting when ribbon reversal is required and capable of causing said lever mechanism to operate said clutch means for connecting .said drive mechanism to one carrier at a time.

2. In a keyboard operated ribbon impression machine, a ribbon drive reversing mechanism comprising a pair of ribbon spool holders rotatably mounted on said machine .for having the ribbon extend therebetween, dropper means :associated with each spool holder for detecting when ribbon reversal is required, a pair of spool drive spindles each on one of said holders, clutches connected to said spindles, means operativcly connected to said machine and said clutches for driving each clutch in an opposite direction, clutch operating levers associated with said iOidQIS for operating said clutches, linkage connecting said clutch operating levers for operating said clutches at the same time with one clutch being engaged and the other disengaged, levers pivoted respectively to said clutch operating levers and positioned for being engaged by said dropper means associated with each spool holder, and means operable by said keyboard for rocking said last mentioned levers in such a manner that if one lever is engaged by said dropper means, said clutch operating levers are actuated to disengage one of said clutches and simultaneously engage the other of said clutches.

3. In a keyboard operated ribbon impression machine, a ribbon drive reversing mechanism as claimed in claim .2, wherein lever mechanisms are operatively connected to said keyboard and each to said lever carried by said clutch operating levers of each spool holder for rocking said levers simultaneously in opposite directions.

4. In a keyboard operated ribbon impression machine, a ribbon drive reversing mechanism as claimed in claim .2, wherein each of said dropper means has a plunger and said levers carried by said clutch operating levers have tail portions arranged to move across the path of said plungers for being restrained when engaging a plunger and caused by further movement to rock their respective clutch operating levers.

5. In a keyboard operated ribbon impression machine, a ribbon drive reversing mechanism as claimed in claim 2, wherein a detent device is associated with one of said spool holders and locating means is carried by one of said clutch operating levers for cooperating with said detent device to determine opposite settings of said clutch operating levers wherein one clutch is engaged and the other disengaged.

6. In a keyboard operated ribbon impression machine, a ribbon drive reversing mechanism as claimed in claim 2, wherein a yieldably mounted roller is associated with one spool holder and one of said clutch operating levers has a cam surface and recesses for cooperating with said roller to determine opposite settings of said clutch operr ating levers wherein one clutch is engaged and the other is disengaged.

References Cited in the file of this patent UNITED STATES PATENTS 1,937,692 Going Dec. 5, 1933

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