US1225331A - Type-writing machine. - Google Patents

Description

W. F. HELIVIOND.

TYPE WRITING MACHINE. APPLICATION FILED MAYE. 1915.

Patented May 8, 1917.

releasably connecting applications, tor connecting the line-space wheel to'the 'WILLIELM F. HEL'MOND, GF HARTFORD, GUN

VJBJETER CQIILPADTY,

OF HE W KGB/Eli, 311 321, A GUBJPQB,

t .LE Ambit. l 1a Specification c Application filed may 1915.

To all whom it may concern:

Be it known that l, lViLLiAM llnniirono, a citizen of the United States, residing in Hartford, in the county of rlartford and State of Connecticut, have invented certain new and useful lmprovenients in Type-- ll riting Machines, is a specification. r

This invention relates to mechanism for the platen and linespace wheel or a typewriting machine to per ni-it the platen to be rotated independently of the line-space wheel to any desired position of adjustment.

lhe invention involves improvements over the mechanisms shown in my co-pending aplications Nos. 837,658, filed May 11, 1914:, and 735,611, filed December 9, 1912. In said I have shown a friction clutch platen, said clutch comprising a druni and a pair of clutch arms or grips within the drum. Said grips are expansibleinto gripping engagement with the inner periphery of the drum by means which forces apart adjacent ends of the grips; the opposite ends of the grips bear against a split block, which may be expanded by an adjusting device, shown as a tapered screw, to regulate the power with which said grips hold the drum.

In practice, it is found that there is a tendency for the adjusting screw to work loose and thereby reduce the holding power of the clutch. A feature of the present invention relates to means for preventing the adjusting screw from work ng loose. Such means may comprise a binding screw by which the two parts of the split bearing block may be drawn toward each other to grip the adjusting screwand therebyprevent it from working loose. The parts of the split block in which the binding screw is mounted may project through an opening in the cover plate of the drum, so that the binding screw is accessible for adjustment. The tapered adjusting screw may also be accessible for adjustment through an opening in the cover plate.

A further feature of the invention relates to the use of the platena'elease clutch between the platen and line-space wheel, in combination with mechanism, such as a billing attachment, for intermittently rotating the platen throu h a predetermined distance,

8 greater than a line-space of which the following distance. The bill-- Letters Patent.

Serial No. 36,218.

ing device is designed to rotate the platen backwardly and forwardly at each operation, through fixed distanceawhich are generally a whole number of line-space intervals; and for this purpose may comprise an operating lever and pawl to rotate a ratchet wheel fixed to the platen, said ratchet wheel having the same number of teeth as the line? space wheel. The exact position assumed by the platen when it has been rotated by the billing device, is determined by the usual spring detent in engagement with the linespace ratchet wheel. it is desirable that the line-space ratchetwheel shall be in register with that of the billing device, so that said detent will be properly seated on its ratchet wheel at the conclusion of the forward stroke of the billing device, and also so that the driving pawl of the billing device will be timed to register with its ratchet wheel. Flt has been found 'in practice that when the friction clutch is employed for releasably connecting the line-space wheelwand platen, the operation of the billing device has a tendency to cause slight creeping; orrelative rotation of the line-space wheel and platen. Theextent of thiscreeping at each operation of the billing device be extremely small or imperceptible and negligible for one or a few operationa'but such creeping is cumulative, and when the billing device is operated many times, the creeping may become an objectidnable feature. Thatis, the position of the platen relative to the line-space wheel, and therefore the position in which the platen is held by the linespace wheel and its detent, even if correctly adjusted to the billing mechanism at the commencement of the billing operations, is gradually shifted, and the ratchet wheel of the billing device is moved out of register with the line-space wheel, and out of adjustment relative to the driving pawl. As a result, the distance through which the platen is rotated by the billing device is varied, the positioning and holding of the platen by the line-space wheel detent is rendered unreliable, and the driving pawl for the ratchet wheel of the billing device cannot be depended upon to engage the proper tooth of its wheel, so that the distances through which the platen is rotated by two consecutive operations of the billing devicemay differ bya full line-space.

in the present linvention, this difficulty is overcome by the provision of means for positively locking the clutch parts against rela tive rotation, and in such relation that the line-space ratchet wheel is in register with the ratchet wheel of the billing device. For,

, inafter appear.

In the accompanying drawings,

Figure 1 is a perspective view, partly broken away, showing the platen of an Underwood typewriting machine with the present invention applied thereto.

Fig. 2 is a sectional perspective view of the clutch parts disassembled.

Fig 3 is view of the tapered adjusting screw.

Fig. 4 is a face view, showing the clutch parts released.

Fig. 5 is a similar view, showing the clutch parts in operative position.

Fig. 6 is a perspective view of the adjustable spacing block for the clutch grips.

Fig. 7 is a part sectional elevation view of the mechanism shown in Fig. 1.

, A rotary platen 11 is fixed to an axle 12 journaled in the platen frame 13, mounted in the carriage 14. Line-space rotations of the platen may be effected by the operation of a line-space lever 15 on a pivot 16, and having an arm 17 to actuate a slide bar 18, to which is pivoted a pawl 19 to drive a line-space ratchet wheel 20. A spring-actuated detent 20 is arranged to seat between adjacentteeth of the wheel 20 and hold the latter at line-space intervals.

The wheel 20.may be connected to the platen through the intermediary of a friction clutch, comprising a clutch part or drum 21, and a disk 22 within the drum. The disk 22 is provided with a hub 23 fixed to the platen axle 12, as by a locking pin 24. The hub 25 of the drum 21 is journaled on the hub 23 and is fixed to the line-space wheel 20, as by means of a pin 26. A pair of clutch arms or grips 27 within the clutch drum 21 and lying against the face of the disk 22, may be spread or expanded into frictional clutching engagement with the inner peripheral face of the drum 21. The lower. ends of the grips 27, Figs. 4 and 5, abut against an adjustable spacing block 28, which may be secured to the disk 22 by pins 29, The block 28 is bifurcated or split by ing the grips 27 and thereby regulating the holding power of said grips.

The grips 27 are spread into gripping en-,

gagement with the clutch drum by means of a pair of levers 32 fulcrurned on a floating pin 33 movable laterally to equalize the pressure on the grips 27; said pin being seated in notches in said levers. Interposed between the levers 32 and the grips 27 are pins or rollers 34 which seat in recesses in the said levers and grips, thereby forming knuckle joints connecting said levers and grips. The actuating levers 32 extend to opposite sides of the platen axle 12, and when they are in contact with the axle, as shown in Fig. 4, the grips 27 rest against the drum, so that said with it the line-space wheel are tate relatively to the grips 27.

The lower or inner ends of the actuating levers are spread to effect a clutching engagement of the grips with the drum by means of a clutch-operating cam The cam is slidable longitudinallyon the platen axle, and the inner end of the cam is tapered to enter between the. axle 12 and the clutchactuating levers 32 to spread the latter to the Fig. 5 position when the cam is moved inwardly. The grips 27 may be made of cast iron or other practically rigid or non-elastic material, to insure positive action, and the levers 32 maybe made of elastic material, permitting the levers to yield slightly when spread by the operating cam. The spring in the levers 32 insures an easy operation of the cam 35, and within certain limits compensates for wear, uneveness or other variations, while insuring an effective gripping action of the clutch parts. The cam 35 is operated by a button 36 to which are connected rods 37, 38, extending through the hub of a hand wheel 39, fixed drum, and free to roto the platen axle, said rods slidable longitudinally in said hub, and at their inner ends having a lost motion connection with the cam 35. Said lost motion connection may be provided for by. heads 40 on the inner ends of said rods; said heads working in a cup or hollow enlarged end 41 of the cam;

The clutch-operating cam 35 is locked in its operative position by a latch 42, which when the cam is moved inwardly, drops over the outer end of a pin 43 connected to said lightly cam, and thereby prevents the cam from moving outwardly. The latch may be thrown to locking position by a spring (not shown) and while in locking position seats in a I'QdllL'id portion 44 of the rod 38. When the button 36 is drawn outward to release the clutch, the latch 42 is cammed outward by the rod 38, to release the pin 43 while the lost motion between the cam and the button 86 is being taken up. The continued outward movement of 'sa id button then withdraws the cam 35 and releases the clutch.

A cover plate 45 for the clutch drum 21 is spaced from the disk by spacing blocks 46 and secured in place by screws 47 extending through the cover plate and threaded into the blocks 46.

It has been found in practice that there is a tendency for the adjusting screw 31 to work loose and thereby weaken the clutch. To overcome this ditiiculty, a, binding screw 48 is provided which may extend freely through an opening spacing block 28, the end of thescrew being threaded into a threaded opening 50 in the opposite side of the block. The binding screw is set up so that its head bears against 7 the block and the latter is caused to tightly grip the adjusting screw 81 and prevent it from working away from its. adjusted position. The openings 49 and 50 may be lo- 'cated in lugs 51 and 52 formed on the block 28, whereby the binding action of the screw 4S is increased, and as said lugs project outwardly through an opening in the cover plate 45, the binding screw is brought into convenient position for manipulation.

The invention provides means for locking the clutch parts together, so as to positively prevent relative rotation of the platen and line-space wheel. Said locking means may comprise a locking screw 53 which may extend through openings in the drum 21 and disk 22. The screw has a close it in said openings, so that relative rotation of the clutch parts is positively prevented. The threaded end of the locking screw may enter a correspondingly threaded bore 54 in said screw. in place.

The locki 1g means just described of special value when used in combination with a billing device or other means for intermittently rota 'ng the platen through predetermined fiXe' distances reater than linespace distances. The billin device may be of the construction shown i1 the patent to VVoodford 923,749, to which reference may be had for a detailed description and illustration thereof. It will be understood that the present invention is not limited to use with any particular form of billing or like mechanism, the present form being chosen 55 for the purpose of illustration.

The billing device may comprise an operating lever 55, mounted for rotation about the platen axis, and carrying a driving pawl 56, to drive a ratchet wheel 57 having a fixed relation to the platen. .The number and angular spacing of the teeth 57- on the wheel 57 correspond ratchet wheel 20. The throw of the lever 55 may be limited in both directions'by suitable 5 stops. One of these stops 58. is shown as .terminesv the rotary 49 in one side of the the adju ing screw 31, thereby locking both a wheel of the billing to those of the line-space carried on an arm 59 mounted for rotary adjustment about the platen axis and which may be held in any position 0t adjustment by means of a pin carried thereby to enter stop openings 60 in a stationary disk 61 which may have an adjustable connection 62 with the platen frame. The openings 60 are preferably spaced at angular intervals equal to those of the ratchet teeth 57*.

It will be noted that the locking screw 53, which is used to lock the clutch parts together while the billing device is in use, dc-

position of the disk 22 and platen relative to the line-space wheel, and therefore determines the relative position of the two ratchet wheels 20 and 57. This relation is such that the two ratchet wheels are in register. The platen, therefore, when in any line-space position, determined by the spring detent 20 hearing between adjacent teeth of the line-space wheel 20, holds the ratchet wheel 57 in operative relation to the driving pawl 56. In

other words, the driver 55 and its pawl 56' when returned to starting position after each operation is always in the same operative position relative to the teeth of the wheel 57, as any creeping of the platen relative to'the line-space wheel is positively prevented. The distance through which the platen is rotated by the driver 55 also remains constant, and the platen and linespace wheel are always brought by the driver to a position for the detent 20 to seat squarely between adjacent teeth without the platen being forced by the'detent to such position. It will thus be seen'that the locking screw serves gaging means by which the line-space wheel is brought into register with the ratchet device, thereby insuring an operative and correct adjustment, and in the second place, positively prevents the line-space wheel from creeping or being moved out of adjustment.

Variations may be resorted to within the scope of the invention, and portions of the improvements may be used without others.

Having thus described my invention, I claim:

1. The combination with a platen and a line-space wheel, of clutch mechanism connecting said platen and wheel, comprising clutch parts movable into and out of gripping engagement and means forming an inclosing casing for certain of the clutch'parts, an adjusting device within the casing for adjusting the clutch parts to thereby regulate the holding power of the clutch, and locking means located externally of the easing, and thereby accessible for locking said adjusting device in its adjusted position.

2. The combination with a platen and a line-space wheel, of clutch mechanism con necting the platen and line-space wheel,

in the first place as a said. mechanism comprising clutch parts movable into and out of gripping engagement, means forming an abutment for one of said parts, a wedge for adjusting said abutment, means forming an inclosure for certain of said clutch parts, and a locking device operable to lock said wedge in ad justed position, said locking device located externally of said inclosure, and thereby accessible for operation.

3. The combination with a platen and a comprising lugs or projections extending through an opening or openings in said inclosure, and a locking screw mounted in said projections and accessible for operation from the outside of the inclosure, to clamp or look saidexpansible parts to said wedge and thereby lock .the latter in its adjusted position.

4:. The combination with a platen and a line-space wheel, of clutching mechanism for connecting the platen and said wheel, said mechanism comprising a drum having a peripheral bearing surface, a pair of grips extending along opposite sides of said bearing surface and movable into and out of frictional holding contact with said surface,

I a split block against which adjacent ends of the grips bear, an operating device for moving the opposite ends of said grips into position to cause them to grip said surface, an adjusting screw, the opposing faces of said block having threaded sockets to receive said screw and in which the screw is adjustable to expand said beaing block and thereby change the position of the grips relatively to the operating device to regulate the pressure with which said grips will engage said surface when moved to gripping 'while the platen is in any position of rotary adjustment relative to the line-space wheel;

, a device for rotating the platen through distances greater than a line-space distance, said device comprising a driving ratchet connected to rotate with the platen, a driver having a pawl to engage said ratchet and thereby rotate the platen through a predetermined fixed distance, and means to positively lock the line-spaceratchet wheel to rotate with the platen, said locking means arranged to hold the line-space ratchet wheel in register with said driving ratchet. 6. In a typewriting machine, the combi-' nation with a roller platen and a line-space ratchet wheel, of a detent to yieldingly hold the ratchet wheel at line-space intervals, a

friction clutch comprising parts connected I to the platen and wheel respectively, means for frictionally holding said parts together to cause the platen and line-space wheel to rotate together while in any relative position of rotary adjustment, a billing device comprising a driver, means connected to rotate with the platen and operated by the driver to rotate the platen a predetermined fixed distance at each operation, and a locking screw to lock the clutch parts together and positively prevent creeping or relative rotation of the platen and line-space wheel during the operation of the platen by said billing devic WILLIAM F. HELMOND.

Witnesses SHIRLEY E. GLEDHILL, JOHN J. BASKERVILLE.

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