US2126356A - Typewriting machine - Google Patents

Description

Aug. 9, 1938. l R. G. THoMPsoN l v 2,126,356 TYPEWRITING MACHINE FiledvFeb. 2o, 1957 ATTORNEY Patented ug. 9, 1938 PATENT OFFICE TYPEWRHTHNG MACHINE Application February 20, 1937, Serial No. 126,902

17 Claims.

This invention relates to typewriting machines and with regard to certain more specific features thereof, to a carriage mounting and distance regulator for such machines.

The invention has a particularly useful application to noiseless typewriters of the character involving a controlled thrust or pressure of the type bars toward the platen, as distinguished from. machines in which the writing is effected l0` by uncontrolled impact of the type bars on the platen.

In noiseless typewriters the type heads are given their final movement toward the paper on the cylindrical platen by hammers, sometimes called momentum accumulators and each type bar moves to a fixed printing plane and exerts a typing pressure within the range of approximately l5 to 25 pounds. Difficulty has been experienced in obtaining a sharp and uniform write and good manifolding results and this is due in large part to the failure of the platen to resist the normal type-action pressures. Some or all of the imprints are blurred and the rearlward yield of the platen destroys the full typepressure effect and limits the number of legible copies.

Not only does the platen yield rearwardly under type-bar pressures but it has a tendency to yield laterally or twist when the carriage is `moved rapidly to a distant stop and this, in accentuated cases, produces a banking-over of the platen carriage at the left margin of the machine. When this happens the rst letter of a line of typing is positioned in advance of the first letters of previous lines, and the regularity of the left margin of the sheet is destroyed.

The objectionable features above stated are believed to be due in major part to the construction and mounting of the center tie of the ma- 40chine which is slidably mounted in ways machined in a cross bar of the frame and in a comb attached to said cross bar. Under the most careful machining obtainable with reasonable tolerances to suit commercial practice the slide mounting allows a slight fore-and-aft rock and a lateral twist of the center tie. An arm upstanding from the rear of the center tie is depended on to'resist rearward movement of the platen and this resistance is oifered in the rst instance with the movements allowed by the slide clearances to the end that rigidity of the center tie is lacking.

That these difculties have been recognized is evidenced by the fact that a complicated series of adjustable stops has been employed to set the center tie up as closely as it is possible to do so and still permit the sliding movement of it to regulate the distance of the platen in respect to the printing plane. This distance regulation is deemed necessary for the accommodation of varying numbers of sheets around the platen. If a single sheet is to be typed the carriage and its platen are set forwardly to suitably present the sheet to the type bar at the end of its stroke where its pressure is predeterminately correct for imprint. If several copies are to be made the carriage and its platen must be set rearwardly so that the outermost sheet on the platen will not be unduly advanced into the Xed path of movement of the type bar and thus Vary the pressure to the sacrifice of good writing and maniiolding.

In machines employing the slidable center tie a series of curved springs are mounted on the cross bar of the main frame at either side and their free ends bear on the center tie to urge it rearwardly. An eccentric operated from a handie at the front or side of the machine is used to urge the center tie forwardly in opposition to these springs. Thus the necessary fore-and-ait adjustment of the center tie and the platen carried thereby is obtained. clearances must not be too greatly reduced by any set-up screws or other adjustments or the springs must fail to perform their function.

So it has become a matter of extremely nice adjustment of set screws to minimize the foreand-aft rock of the center tie, and of other adjusting devices on either side of the upstanding arm to minimize the lateral twist, and at the same time leave a capability of bodily adjustment of the center tie toward and from the printing plane. Certain of the adjusting devices are set up to hold with a small surface friction and after carefully making them at the factory as a necessary precedent to test they must be immediately remade in the eld after transportation of the machine. If the machine receives any considerable shock in use these adjustments must be made again by someone experienced in typewriter servicing. The making and remaking of these adjustments adds greatly to the cost of manufacture, marketingand maintenance of the machine.

Obviously the slide The invention has, therefore, for one of its objects, to provide a machine securing better writing and manifolding, which machine may be produced and maintained with less expense.

It is another object of the invention to provide a means of avoiding the previously described marginal banking-over of the carriage.

It is another object of the invention to eliminate the necessity for frequent adjustments and provide a machine which may be subjected to the rigors of transportation and delivered in the field without necessity for adjustments by the consignee.

The invention accordingly consists in the various features of construction, combination of elements and arrangements of parts which will be exemplified by the description of a preferred form of the invention hereinafter set forth and the scope of the application of which will be indicated in the appended claims.

In the accompanying drawing wherein is shown one of various possible embodiments of the inventiont- Fig. 1 is a view in right side elevation, broken at the rear into vertical central section, of a type- Writing machine embodying the improved carriage mounting and distance regulator.

Fig. 2 is a view in top plan of the carriage mounting and distance regulator shown in Fig. 1.

Fig. 3 is a view in rear elevation of the typewriting machine shown in Fig. 1, with a part of the rear plate broken away to show more clearly the carriage mounting means, and

Fig. 4 is a fragmentary View in side elevation of the upper portion of the rear plate showing the means for opposing return and tabulating movements of the carriage.

Referring now more particularly to the drawing a main frame is indicated at 3D having a left side wall 3| and a right side wall 32. Projecting inwardly from these side walls are spaced lugs 33 to which are secured, by dowel pins 34 and screws 35, the lower ends of substantially flat sheet metal springs 36.

The lugs 33 on each side wall are spaced apart preferably on an angle of 10 from the horizon.- tal, as shown in Fig. l of the drawing, and springs 36 extend upwardly in parallelism from the front face of the forward lug and the rear face of the rear lug at right angles to the alignment of the lugs fore-and-aft of the machine. Thus two sets of spring supports are provided, one at each side of the machine.

Across member indicated generally at 40 is preferably a casting having a lateral plate portion 4| terminating in somewhat enlarged ends 42 and 43, and these ends have their front and rear faces machined to fit between the upper ends of the springs 36 of each set and be secured therein by dowel pins 44 and screws 45. Thus the cross member 46 is securely held in position within and between the side walls of the frame with a capability of fore-and-aft movement owing to the resilience of the springs 35.

The cross member 40 has a central upstanding arm 46 at the rear thereof preferably cast integral with the cross plate 4|. In the region of an elbow 41 spaced webs 48 extend rearwardly and turn outwardly at the extreme rear to form flanges 50 to which is secured a tabulator casing The webs 48 continue upwardly reinforcing the arm 4G and defining a channel in cross section of the upper part of said arm.

The cross plate 4| is provided with upstanding ears 52 at each of its ends 42-43 and each ear has threaded therethrough a pivot screw 53 for pivotally supporting a case-shift or balancing frame indicated generally at 54. The frame 54 is in the form of a cast cross bar 55 with enlarged ends 56 to the outer faces of which are xed adjustable plates corresponding to the one shown in Fig. l at 51. Rearward extensions 58 at opposite ends of the case-shift frame are pivotally connected with ears 68 depending from a track 5| which supports a carriage rail 62 for transfer movement on suitable anti-friction rollers indicated at 63. The case-shift frame 54 may be moved pivotally on screws 53 to raise the carriage to upper case position by either manually operated or manually selected power driven means and in its movement it may be suitably counterbalanced by conventional spring means not shown. Adjustable stop means indicated generally at 64 limits the upper case throw of the carriage and adjustable stop means indicated generally at 65 limits the lower case position of the carriage.

A carriage is schematically indicated in Fig. 1 of the drawing and has the usual oppositeend frame members 1| to which is secured a rigid bar 12. This bar and the carriage bar 62 complete the carriage frame and a roller platen 13 is journaled in the opposite ends 1| of the frame.

The upper end of the upstanding arm 46 of cross member 40 has a vertical central slot 15, and a sheet metal angle member 16 having a corresponding slot 11 is iitted over the upper end of arm 46 and secured in position thereon by screws 19 which also secure a bridge 18 to the rear of said arm in the channel heretofore referred to as being formed by the continuation upwardly of webs 48. The front face of angle member 16 has a finished surface against which rail 12 of the carriage slides both in the transverse movement of the carriage and in the up-and-down case-shifting movements thereof. The rail is guided in these movements by an organization of parts comprising an angle member 88 having a rear down-turned end 8|.

A bolt 82 passes rearwardly through a washer 83, a slot 84 in the down-turned end 8|, a square nut 85 arranged in slot 11, a clip 86, a Washer 81 and a nut 88. The rear end of bolt 82 is slotted for rotation of the bolt in nut 85 which latter is loosely but non-rotatively fitted in slot 11. To adjust the angle member 80 toward and from the face of angle member 16 the nut 88 is loosened by a hollow socket wrench and a screw-driver is inserted through the wrench to turn bolt 82. When the proper adjustment is obtained the bolt is held by the screw-driver and the nut 88 is turned up tight by the socket wrench.

The clip 86 bears against the rear face of angle member 11 and has a forwardly-turned upper end 90 which projects through slot 11 and overhangs the rear edge of the rail 12. A stud 9| secured to the front center of the angle member 80 has a flange 52 which overlies the forward upper edge of rail 12. Thus the adjusting device is supported at the front and rear of the rail. Suitable anti-friction rolls 93 on the angle member 80 bear loosely against the front edge of the rail and as the bolt is adjusted in one direction these rollers urge the rail against the front face of angle member 16.

Thus it will be seen that the carriage rail 12 is tied to the upstanding arm of the cross member by means which maintain this relation throughout the case-shifting movements of the rot carriage and throughout the carriage transversing operations.

j A rigid back plate 94 is attached to the rear ends of the opposite side walls as indicated at .95,and 'rises to La position approximately opposite the top of the roller platen I3. In the up-per portion of this back plate an adjusting screw 9S is threaded to abut the point of the screw against the bridge 18 on the arm 16. The screw has a knurled head 97, the inner face of which has a circumferential series of spaced indentations 98 adapted to be engaged by a spring-pressed detent located in the rear ofthe upper portion of the back plate. Around the periphery of the screw head are numerical indications corresponding to the number and-position of the indentations 98 (see Fig. 4). The adjusting-screw head has a top |0| which limits its rotation to slightly less than 360 byjengagement with the detent |00. Thus it will be seen that the axial movement ofthe adjusting screw is limited to substantially the pitch of one thread and that this movement may be dividedY into a multiplicity of increments inrotating the knurled head to present one indentation 98 after another to the detent Hill." By this means the cross member 46 may beiZ moved forwardly `a very limited extent to advance and will carry with it the carriage rail 12 and the entire carriage frame and the platen mounted thereon so that the platen will be advanced toward the eXtreme of movement of the type bars, one of which is indicated at m2 in Fig. l,',or, in other words, toward the` printing plane. It is to be noted that the rigid back plate 94 carries the screw 9B at a point approximately opposed to the direction of thrust of the type bar and that the carriage rail 12 is in approximately this line of thrust. For purposes of visibility this line is at an angle of 10 degrees inclination from the horizontal and the adjusting screw S6 and the rail 'l2 are both adapted to this inclination. The lugs 33 on the side walls of the frame are so shaped and positioned that the flat spring supporting members must be exed forwardly approximately elle when the adjusting screw Se is advanced to its most forward position. Thus the entire carriage support is under a constant bias rearwardly forcing the bridge 18 at all times against the end of the adjusting screw Sii. Therefore as the screw is turned in a direction to cause retreat of its end the springs 36 continuously urge the carriage arm into engagement with the end of the screw. When it is desired to accommodate a large number of copies on the platen the adjusting screw is let oif to desired position and the springs 36 cause a retreat of the carriage from the printing plane.

The springs 36 are preferably of steel about 3" in height by 1l wide by .04 thick and as supported andengaged with the cross member provide substantial opposition to torsion, but in order to further reinforce the upstanding arm of the cross member spaced ears |03, which are cast on the forward face of the back plate at the upper portion, embrace the upper end of the upstanding arm 46 and are provided with inwardly projecting threaded members H34 having flanges |05 which bear against sheet metal keepers |06 secured to opposite sides of the arm by screws |l!'|, the Shanks of which pass through slots |08 in the keepers and thread into the webs 48 of the arm. Each keeper is provided with a fore-and-aft slot Ill] extending forwardly from the rear edge of the keeper, and in these lslots are located ends I I2 which project beyond the flanges |05 of the screw members |04.

By the above described means tabulator and carriage return shocks are substantially opposed yet fore-and-aft adjustment oi the cross member is permitted by the slot ||0 by reason of the fact that the screw members are set up to bring the iianges |05 very lightly against the keepers |06.

By the above described relatively inexpensive construction the roller platen 13 is rigidly held to resist type bar pressures and the shocks of tabulation and carriage return on the upstanding arm 46 are stoutly opposed. The first writing on the paper is extremely sharp, clear and uniform, and a large number of carbon copies can be satisfactorily made. As the sliding mounting of a center tie is eliminated all clearances consequent thereto are eliminated and accordingly the necessity for nice adjustments to minimize these clearances is eliminated, thus doing away with the expense of making these adjustments at the factory, remaking them in the field and making them from time to time to maintain the machine in appropriate working condition.

Vihat is claimed isi- 1. In a typewriting machine, platen-carriage supporting means comprising, a spring-supported cross-member, a case-shift frame pivoted on the cross-member, a carriage-supporting track on said frame, and a platen-carriage on said track.

2. In a typewriting machine, platen-carriage supporting means comprising, a main frame, upstanding spring pieces fixed to the main frame, a cross-member fixed to the upper ends of said spring pieces, case-shifting means pivoted on the cross-member and including a track, and a platencarriage on said track.

3. In a typewriting machine, a platen-carriage support comprising, a main frame, spaced sets of substantially parallel leaf springs secured to the frame, a cross-member xed upon the upper ends of the springs of each set, and a platen-carriage pivotally Ysupported by said cross-member for case-shifting movement. v

4. In a typewriting machine, a platen-carriage support comprising, a main frame having side walls, a set of upstanding substantially parallel leaf springs inside each side wall, each spring having its lower end secured to the frame, a cross-member having its opposite ends fixed to the upper ends of the springs of each set, and a platen-carriage supported on said cross-member.

5. In a typewriting machine, a main frame having side walls, .a set of upstanding parallel springmetal members supported by the side walls of the machine, a cross-member held on the upper ends of the spring sets, a case-shift frame pivoted on the cross-member, a carriage track on the caseshift frame, a carriage on the track, anti-friction bearings between the track and carriage, and a cylindrical platen journaled in said carriage.

6. In a typewriting machine, a main frame, a platen-carriage having spring supports which bias it rearwardly, and an adjustable abutment rearwardly of the platen-carriage for moving said carriage forwardly to different adjusted positions against the action of said'spring supports.

7. In a typewriting machine, a main frame, a platen-carriage having parallel spring supports which bias it rearwardly, and an adjustable abutment rearwardly of the platen-carriage for moving said carriage forwardly to different adjusted to said track, a cross-member, upon which said upstanding spring pieces having ends secured to positions against the action of said spring supports.

8. In a typewriting machine, a main frame having an adjustable abutment, a platen-carriage having two sets of parallel spring supports, one at either side of the machine, which'spring supports bias the platen-carriage rearwardly against said abutment, and means for moving said carriage forwardly to different adjusted positions against the action of said spring supports.

9. In a typewriting machine, a main frame having side walls and a back wall, a platen-carriage having end walls and having a track bar and a rail between the carriage end walls, a track for said carriage, a case-shift frame connected case-shift frame is pivotally mounted, having an arm extending upwardly, a pair of substantially parallel leaf springs secured to the main frame inside each side wall with their upper ends secured to the` cross-member, and an adjusting device in the back wall of the main frame behind the carriage railfor forwardly moving the upwardly extending arm.

10. In a typewriting machine, a main frame,

said frame, a cross-member having its ends secured to the other ends of said springs and having an upwardlyv extended arm, a carriage supported by said cross-member, a platen on said carriage, a rail on said carriage bearing against the upwardly extended arm of the cross-member, and means for adjusting said arm forwardly against the action of said springs.

11. In a typewrit'ing machine, a main frame having side walls and a back wall, upstanding substantially parallel leaf spring sets xed adjacent each side wall, andy having free ends, a cross-member secured tothe free ends and biased rearwardly by the springs, a case-shift frame on the cross-member, a supporting track, a carriage slidably mounted on said track, a roller platen journaled in said carriage, a rail on said carriage, an arm on said cross member against which the rail bears, and means on the back Wall for adjusting the cross-member forwardly.

12. In a typewriting machine, a main frame having a rear wall, a cross-member, spring means for supporting said cross-member from said frame, said cross-member having an upstanding arm at the rear of the machine, a platen-carriage pivotally supported on said cross member having a rear rail bearing against the upstanding arm, and means for maintaining the relation of the rail and arm during case shifting Operations.

13. In a typewriting machine, a main frame having side walls and a rear wall, a platen-carriage, iiexible supporting means for said platencarriage, an adjustment device supported in the rear wall adapted to resist rearward movement of the carriage and to be moved to adjust the carriage in a forward direction.

14. In a typewriting machine, a main frame having side walls and a rear wall, a platen carriage having arail, parallel motion means for supporting said platen-carriage, 'and means in the rear wall approximately directly behind the rail for moving the carriage forwardly on said sup-- porting means to different positions of adjustment.

15. In a typewriting machine, a main frame having side walls and a rear wall, a platen-carriage having a rail, springs supporting said platen-carriage adapted to bias it` toward the rear wall, means in the rear wall approximately directly behind the rail for moving the carriage forwardly against the action of said springs to different positions of adjustment, and types movable to a printing point substantially in line with said rail and said carriage moving means.

1G. In a typewriting machine, a platen, a frame, and upstanding spaced parallel spring members adapted to support the platen on the frame with capability of adjustment relative to the printing plane.

17. In a typewriting machine, a platen, a frame, and upstanding spaced iiat sheet-metal parallel spring members adapted to support the platen on the frame with capability of adjustment relative to the printing plane.

RUSSELL G. THOMPSON.

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