US3239050A - Ribbon drive for typewriter construction - Google Patents

Description

J. E. THOMSON RIBBON DRIVE FOR TYPEWRITER CONSTRUCTION March 8, 1966 Original Filed March 21, 1960 par/V17 'INVENTOR. 7 was Z flomsofl,

March 3,1956 J. E. THOMSON 3,239,050

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March 1966 J. E. THOMSON 3,239,050

RIBBON DRIVE FOR TYPEWRITER CONSTRUCTION Original Filed March 21. 1960 5 Sheets-Sheet 5 ii 1 24 131! if [/4 [i7 oo QQQOOQ INVENTOR. 72177765 I7'%amsa7z United States Patent 3,239,050 RIBBON DRIVE FOR TYPEWRITER CONSTRUCTION James E. Thomson, Munith, Mich, assignor, by mesne assignments, to Western Stamping Corporation, Jackson, Mich., a corporation of Michigan Continuation of application Ser. No. 202,928, Apr. 23, 1962, which is a division of application Ser. No. 16,368, Mar. 21, 1960, now Patent No. 3,057,449. This application Oct. 20, 1964, Ser. No. 405,294

7 Claims. (Ci. 19715l) This invention relates to typewriters, and more particularly to a construction and method of manufacture of relatively inexpensive typewriters usable both as toys and for school and home purposes. This application is a continuation of application Serial No. 202,928 filed April 23, 1962, now abandoned, as a division of application Serial No. 16,368, filed March 21, 1960, now Patent No. 3,057,449.

It is an object of the invention to provide a novel and improved typewriter construction which incorporates a standard keyboard and platen arrangement, together with ribbon feed, paper release and other features found on standard ofi'ice machines, but which nevertheless may be mass produced at extremely low cost from inexpensively fabricated parts.

It is another object to provide an improved typewriter construction of this nature which has a novel ribbon feeding and reversing mechanism of inexpensive a n d efficient construction.

Other objects, features and advantages of the present invention will become apparent from the subsequent description taken in conjunction with the accompanying dr awings.

In the drawing:

FIGURE 1 is a top plan View of the improved typewriter of this invention, with the lid removed, showing the general contour of the base;

FIGURE 2 is a cross sectional view in elevation taken along the line 2-2 of FIGURE 1;

FIGURE 3 is a cross sectional view in elevation taken along the line 3--3 of FIGURE 2;

FIGURE 4 is a plan cross sectional view taken along the line 4-4 of FIGURE 2 and illustrating parts of the ribbon feed mechanism;

FIGURE 5 is a cross sectional view in elevation taken along the line 55 of FIGURE 1;

FIGURE 6 is a fragmentary sectional plan view corresponding to FIGURE 4 showing a second form of the invention; and

FIGURE 7 is a fragmentary cross sectional view in elevation, parts being broken away, taken along the line 7-7 of FIGURE 6.

Referring now to the drawing:

The carriage assembly is generally indicated at 85 and comprises a pair of carriage brackets 86 which are supported for parallelogram movement by carriage supporting frame member 38 mounted on base 31. The shape of carriage brackets 86 is best seen in FIGURES 2 and 5. Each bracket comprises a rearwardly extending arm 87 and a downwardly extending arm 88. A rear torsion link 89 comprising a bent wire has a central portion rockably supported by post portions 43 of frame "ice member 38 and a pair of forwardly projecting side legs 91 which have outwardly projecting end crank portions 92 passing through apertures in legs 87 of brackets 86. A forward torsion link 93 is similarly formed, being supported by post portions 42 of frame member 38 and connected to arms 88 of brackets 86 by out turned end crank portions 245. The configuration and arrangement of torsion links 89 and 93 are best seen in FIGURES 4 and 5.

Typewriter ribbon 84 is fed between two spools 205 and 206 which may be of standard typewriter construction. These spools are removably mounted on posts 207 and 208, respectively, being held on the posts by nuts 209 or similar securing means as seen in FIGURE 3. Carriage assembly brackets 86 are provided with pairs of spaced outwardly extending ears 210 and 211 through which shafts 207 and 208 extend, the ears thus supporting the shafts for rotational movement. Brackets 86 are also provided with a pair of upwardly extending angularly bent forked ribbon guides 212, best seen in FIGURES 3 and 5 for guiding ribbon 84 adjacent spools 205 and 206. The lower ends of shafts 207 and 208 are provided with toothed wheels 213 immediately below ears 211 of brackets 86 and cotter pins 214 are mounted on shafts 207 and 208 immediately above ears 211 to hold the shafts against axial movement.

The means for driving ribbon 84 includes a ribbon drive shaft 215 extending across the interior of the typewriter above the key levers and supported by a pair of forwardly extending tabs 216 on brackets 86, these tabs having rearwardly facing open ended slots 217 as seen in FIGURE 2 within which shaft 215 is disposed. Fixedly mounted on shaft 215 are a pair of helical wires 218 and 219, these wires being adjacent shafts 207 and 208 respectively, Wires 218 and 219, which may in practice simply be standard coil springs except that one has a left hand helix and the other right hand, as shown, acts as worms in that they have the same pitch as, and are adapted to mesh with, toothed wheels 213 for rotating the ribbon shafts. The sense of turning of worm 218 is opposite to that of worm 219, so that with shaft 215 intermittently rotated in the same direction, shafts 207 and 208 will be driven in opposite directions, these shafts being driven alternately depending upon which of the two worms 218 and 219 is engageable with its corresponding toothed wheel 213. In the illustrated embodiment, worm 218 is so arranged that it will rotate spool 205 counterclockwise, as seen in FIGURE 1, whereas worm 219 will rotate spool 206 clockwise in FIGURE 1.

The means for driving shaft 215 comprises a toothed ratchet wheel 221 fixed to one end of the shaft and engageable by a reciprocating pawl member 222, as seen in FIGURES 3 and 5. Pawl 222 may be of channelshaped cross section, thus being retained on ratchet 221, and teeth 223 of the pawl are preferably pressed or stamped from the central portion of the pawl in a sawtooth shape such that movement of pawl 222 to the right, as seen in FIGURE 5, will cause clockwise rotation of shaft 215, while retraction of pawl 222 to the left will cause teeth 223 thereof to ride over the teeth of ratchet 221. Pawl 222 may be formed of sheet metal and has an arm 224 extendingfrom one end thereof, this arm being pivotally connected at 225 to a side leg of universal bar 136. Upon counterclockwise swinging of the universal bar 136, as seen in FIGURE 5, pawl 222 will be retracted to the left, and upon return movement of the universal bar under the urging of springs 137, shaft 215 will be rotated to advance the ribbon. The universal bar is actuatable by the spacer 234 and also by the key lever linkages consisting of key levers 45 and bellcranks 54 which are actuated by the typing keys 46 and which actuate type bars 59 through links 58. The detailed arrangement of such components is described in my aforementioned Patent No. 3,057,449.

In order to reverse the ribbon, a handle 226 is provided which projects through an aperture in front housing plate 60. This handle is connected by a bent rod 227 with a lever 228 pivotally supported at 229 on a tab 231 extending from one end of bracket 86, as seen in FIGURE 4. A detent leaf spring 232 is secured at one end to bracket 86 and is engageable at its outer end with lever 228 to hold the lever in either one of two positions, as shown in the solid and dot dash lines of FIG- URE 4. The opposite end of lever 228 has a downturned portion 233 having an aperture into which the adjacent end of shaft 215 extends, as seen in FIGURE 3. The end of lever 228 which is engaged by spring 232 is rounded so that the spring exerts an over-center action on the lever. With this arrangement, movement of lever 228 to its solid line position in FIGURE 4 will cause worm 219 to engage its corresponding toothed wheel 13 while movement of lever 228 to its dot dash line position will cause worm 218 to mesh with its wheel. In order to insure proper engagement in either drive position, the inner ends of slots 217 which support shaft 215 are so located that they will alternately act as fulcrums for the rocking movement of shaft 215 between its positions. The inner ends of the slots are in effect defined by the worm wheels 213.

It should be observed that the illustrated construction of the ribbon drive is extremely inexpensive since no machined parts are required even though a reversing gear drive is provided. Moreover, since worms 218 and 219 will be resiliently urged against their corresponding toothed wheels 213, manual rotation or adjustment of spools 205 and 206 will still be permitted, worms 218 and 219 yielding as their corresponding toothed wheels are rotated. When the carriage 85 is shifted up and down as by shift keys 241 or 242, pawl 222 rocks on its pivotal connection at 225.

Although the ribbon feeding mechanism of FIGURES 6 and 7 is similar to that employed in the first disclosed embodiment, and the ribbon reversing lever 228a, corresponding to the lever 228 is similarly actuatable by means of a link 227a to shift the position of the worm shaft 215a to drive one or the other of the ribbon feeding worm wheels 213a in similar fashion, the link 227a, instead of extending through the front of the case, as in the first embodiment, is pivotally attached to an actuating lever 355 pivoted on the bellcrank pivot rod 55a and projecting upwardly inside the case behind the guide 62a. Lever 355 is fitted with a suitable terminal handle portion 356 at its upper extremity which is readily accessible when the lid 262 is raised. Thus the ribbon can easily be reversed simply by lifting the lid and pushing the finger piece 356 toward the front or rear. Other portions of the embodiment of FIGURES 6 and 7 will be seen to be similar to those of the first embodiment and to require no redescription, similar reference characters being employed with the addition of the letter a to denote corresponding parts.

While it will be apparent that the preferred embodiments of the invention disclosed are well calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.

What is claimed is:

1. In a typewriter having a base, a paper carriage on the base, a plurality of type bars, key means for actuating the type bars, an ink ribbon adapted to coact with the type bars and paper carriage, means supporting the ribbon including a pair of spools spaced from each other on parallel axes, reversible means for driving the spools to actuate the ribbon including a pair of gear wheels, one for driving each spool, a cross shaft extending between the gear wheels and bodily movable transversely of its axis in a plane toward and from the gear wheels, all portions of the shaft being so bodily movable transversely in such plane a pair of gears on the cross shaft individually movable to and from meshing engagement with the respective gear wheels by transverse movement of said shaft, and means for rotating the cross shaft about its longitudinal axis to selectively drive the gears and spools comprising a pawl actuatable by the key means in a line substantially parallel to said plane and having a plurality of teeth serially arranged along said line.

2. In a typewriter construction which, includes a pair of shafts individually rotatable about spaced parallel axes and each of which is adapted to support a ribbon spool and wherein a ribbon connected at its opposite ends to such spools is alternatively actuatable in opposite directions, means for alternatively rotatively driving each of said shafts to so actuate a ribbon, comprising a pair of spaced parallel coplanar worm wheels, one of such worm wheels being connected to each of said shafts, a cross shaft extending substantially parallel to the plane of said worm wheels, a pair of worms carried by said cross shaft and one meshable with each of said worm wheels, means carrying said cross shaft comprising a pair of fixed sup ports spaced from each other and from the center of said cross shaft and also spaced from said worms and having slots therein through which said cross shaft extends for axial rotation and for movement along said slots, the slots extending toward and away from said worm wheels and all portions of the cross shaft being unrestrained against movement laterally of its axis in the plane of the slots, whereby each end of the cross shaft is movable toward and away from one of the worm wheels to carry each of the worms into and out of mesh with its respective worm wheel, and overcenter spring means reacting against said cross shaft at a position spaced from the mid-portion of the cross shaft and urging said cross shaft along the plane of the slots toward and away from the worm wheels, the slots being of limited effective length and at least one end of the shaft extending beyond the worm wheel whereby the cross shaft may pivot about a portion at the end of a slot when such end of the cross shaft is urged laterally toward or away from a worm wheel.

3. In a construction as defined in claim 2, a ratchet wheel on the cross shaft, and a multitooth pawl engageable with the ratchet wheel to impart rotation to the shaft and having its teeth serially disposed in a direction lengthwise with respect to said slots and transversely to the axis of the shaft, and means for reciprocating the pawl in such direction.

4. In a construction as defined in claim 2, a ratchet wheel on the cross shaft, and a multitooth pawl engageable with the ratchet wheel to impart rotation to the shaft and having its teeth serially disposed in a direction lengthwise with respect to said slots and transversely to the axis of the shaft, and means for reciprocating the pawl in such direction, said ratchet wheel and pawl also being spaced from the mid-portion of the cross shaft.

5. In a typewriter construction as defined in claim 4, a universal bar, said pawl being pivotally connected to and actuatable by said universal bar and being of angular form and including a longitudinally serially toothed portion resting on top of said ratchet wheel.

6. In typewriter construction as defined in claim 4, a universal bar, and means connecting the pawl to said universal bar for rocking movement about an axis gencraly parallel to and horizontally spaced from said shaft.

5 7. A typewriter construction as defined in claim 1 wherein said worm wheels, slots and shaft are coplanar and said overcenter spring means reacts against an end portion of the shaft located outside the area between the worm wheels.

References Cited by the Examiner UNITED STATES PATENTS 1,049,291 12/1912 Clayton 197-151 X 1,254,501 1/1918 Henry 197-151 X 1,455,110 5/1923 Crawley 197-151 Hess et a1. 197-151 Going 197-151 Barr 197-151 Garbell 197-151 X Dobson 197-151 X Garbell 197-161 DAVID KLEIN, Primary Examiner.

ROBERT E. PULFREY, Examiner. ERNEST R. WRIGHT, Assistant Examiner.

Claims (1)

1. IN A TYPEWRITER HAVING A BASE, A PAPER CARRIAGE ON THE BASE, A PLURALITY OF TYPE BARS, KEY MEANS FOR ACTUATING THE TYPE BARS, AN INK RIBBON ADAPTED TO COACT WITH THE TYPE BARS AND PAPER CARRIAGE, MEANS SUPPORTING THE RIBBON INCLUDING A PAIR OF SPOOLS SPACED FROM EACH OTHER ON PARALLEL AXES, REVERSIBLE MEANS FOR DRIVING THE SPOOLS TO ACTUATE THE RIBBON INCLUDING A PAIR OF GEAR WHEELS, ONE FOR DRIVING EACH SPOOL, A CROSS SHAFT EXTENDING BETWEEN THE GEAR WHEELS AND BODILY MOVABLE TRANSVERSELY OF ITS AXIS IN A PLANE TOWARD AND FOM THE GEAR WHEELS, ALL PORTIONS OF THE SHAFT BEING SO BODILY MOVABLE TRANSVERSELY IN SUCH PLANE A PAIR OF GEARS ON THE CROSS SHAFT

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