US1414104A - Blanket stretcher for printing rollers - Google Patents

Description

E-. E. STRAWN. BLANKET STRETCHER. FOB PRINTING ROLLERS- APPLICATION man JULY 1.1. mm.

1,414, 1 04, Patented Apr. 25,- 1922.

' fiza'erzz of' 64W mp Z az/z /zmw em stares I nnvms: STRAWN, oFnEs MOINES, IOWA, ASSIGNOR TO THE oMNIGRABH COM'EA'NY,

estes;

i or, nus MOINES, IOWA, A conrona'r-ron;

BLANKET srnn'rcririn r03 PRINTING, noLLEBsf;

Application filed July 11,

To all wj hom it may concern 5 ;Be it known that I, ERV'IN 1E. Sr'na wN, a

citizen oftheU'nited States, and a residentof Des Moines, in the fcounty of Polk and State of Iowa,-have' invented a certain new and useful'BlanketStretcher for Printing Rollers, of'which the following is a specifipationauy r f The object of my invention isito provide 'afbla'nket stretcher of simple, durable and inexpensive construction, designed to be used in connection with a printing roller for sungly stretching and holding a blanket on Such roller. v

More particularly, it is myv object to pro.- vide such a stretcher of the kind hereinafter explained inf-greater detail, whereby 'the blanket will be stretched evenly and held taut during'the' printing operation; A further object is to provide such a stretcher whichcan be mounted in'an ,eX-

'1 tremely' emu space 'withinthe body of the roller. 1 With these and "other objects inview, my

invention, consists Ithe constructioigi ar rangement and comb nat on of the various partsof my device, whereby the obiects contemplated are'attained, as hereinafter more fully set forth, pointed out in my claims, and

illustrated infthel accompanying drawings, in which: p

Figure 1 shows a perspective view '01"- the printing roller equipped with a blanket stretcher embodying my invention.

Figure? shows'a transverse, vertical, sectio-iia'l view through the roller and part of the stretching mechanism; and Figu'ieB shows a Vertical, sectional view through the shaft of one, of the stretcher rollers, the stretcher roller being shown in end elevation.

' Inistret-ohing and tightening and holding a blanket on a printing roller as for instance in ofllset printing, it. is highly desirable, that the blanket-should be evenly stretched and held snug against the roller at all points thereof. The blankets of the kind under consideration may be ordinary rubber blankthe roller.

ets or may be metal or paper sheets. 7

Especially where metal sheets are employed, it is a difficult problem to stretch them evenly and hold them snugly against on the roller by hand, one end will stand Specification of Letters Patent.

For instance, it is frequently 7 found that when a metal blanket is placed i921. Serial No. 433,801;

its length and then when the edges of the" Patented Apr. 251, .1922;

blanket are gripped and pulled, the blanket will not be evenly stretched, and the portion which stood away from the roller will never be snugly engaged against the roller, orj-if the blanket is stretched tight enough to' bring all parts snugly'against the roller, it will be found .thatrcertain parts of the blanke'tliave stretched'or have been pulled out of their true shape] 7 1 It ismy purpose to' provide-a blanket stretcher, whereby any blanket and'particu larly a metal sheet mavbe so st'retche'dthat j the sheet will snugly fit against therollerat. all points and yet will not be pulled out of 1 shape. I i l In the accompanying drawings,'I have v i used the reference numeral 10 toindicate generally a. printing roller of an ordinary type, which roller is mounted on a shaft 11. The roller has in its surface a longitudinal slot 12 and; on opposite sides of said: slotarev stretcher rollerslfi andla mountedo'n shafts The shafts "'15 and- 16 project a 15, and 11 6.

fromthe 'ro'llerlO'jat onefi end thereof, as

shown for instancein Figure (1. e

Onjthe outer eiids ofthe shafts 15 and16- arepinions 17 and 18, whichare arrangedf in mesh with each other. On the shaft 16',

for instance, outside the pinion 18is' aworm wheel'19, which meshes with a worm 20 on sha "t 21 mountedin suitable bear1ngs22 and 23 substantially at right angles witli relation to the shaft 16. f

The shaft 31 has an angular head .24

adapted to be'fengage'dby a socket wrench. The rollers 13' and 1 1, which I have called tened sides 25 and 26, as shown in Figure 2.

the stretching rollers are provided with flati 'F or convenience in description,-the parts will be described as: though the printing roller 10"we re inpos'ition with the slot 12 upwardly.

Before the blanket is placed on theoroller, the stretching rollers are broughtto position where their flat sides 25 and 26 are adstand just below and radially inwardly from the slot 12.

j acent to-and parallel with each other and The surfaces' of the rollers 13 and 1% for a shortwdistance from the upper as at 27 and 28. Theisurfaces of therollers 13 and 14 for a certain distance just beyond the smooth portions 27 and 28 are knurled as at 29 and 30.

The smooth portions 27 and 28 are slightly closer to the longitudinal axes of the stretching rollers than the knurled portions 29. The difference in radius, at the smooth portions and the knurled portions is brought out clearly in somewhat exaggerated showing in Figure 3.

In the practical use of my improved device, the blanket 31 is placed on the roller and the edges of the blanket are forced into the slot 12 until they project adjacent to each other between the rollers 18 and 14.

The shaft 21 is then rotated for imparting rotation to the stretcher rollers in the directions indicated by the arrows in Figure 2. a

It will be seen that when the rollers 13 and 14 are rotated for a very short distance, the smooth portions 27 and 28 will engage and grip-between them the ends of the plate or blanket 31. r i

If the blanket is evenly placed on the roller at both ends and entirely around the roller, the blanket will be stretched evenly until the knurled portions engage and grip the blanket. The rollers 13 and 14 are rotated until the blanket is tightly stretched and smoothly and snugly engages the roller 10. v

If, as sometlmes occurs, the blanket 31 when placed onthe roller 10 byhand does not fit in against the roller 10 snugly at all points, but stands away from the roller 10 at one end' for instance more than at the other end, it will be seen that if the blanket were then stretched by pulling the edges evenly around the rollers 13 and 1a, the end of the blanket which had been looser than the other end would not be stretched tightly, or. the other end of the blanket would be overstretched and pulled out of proper shape. With my device, however, it have found in practical use thatv by providing Vthesmooth surfaces 527 and 28, which first engage the blanket, tlie blanket is then pulled taut, and if one end is a little looser than the other end on the roller 10, the edges'of the blanket nearer the tighter end thereof'will slip somewhat on the smooth surface until the blanket has the same tautness at all points in its length end to end of the roller 10. Thereafter the blanket is engaged by the knurled portions 29 and 30 and drawn tight and snug to a proper position on the roller 10.

On account of the use of the Worm gear and worm. Wheel, the parts are held tight when the blanket has once been stretched to snug position on the printing roller.

Some changes may be made in the details ofstructure of my improved stretcher device without departing from the real-spirit and purpose of'my invention, and it is my intention to cover by my claims, any modified forms of structure or use of rmechanica l equivalents, which may be reasonably included within their: scope.

- I claim as my invention:

1. A blanket stretcher comprising in combination with a roller having a slot therein a pair of parallel stretching rollers adjacent to said slot in the first roller, having flattened faces adapted to stand adjacent to and substantially parallel with each other at one point in the rotation of the stretching rollers, said stretching rollers having adjacent to their flattened faces, corresponding smooth surface portions andadja'cent to said smooth portions knurled surface portions,

whereby when the ends of a blanket are between said flattened faces and the'stretching rollers are rotated, the blanket ends may be first gripped between said smooth portions for PBIIIIIttIIIg SOIHG slippage, and sub'se:

quently by the said knurled portions for proper stretching; v p 2. A blanket stretcher comprising incombination with a roller'having a slot therein 7 a pair of parallel stretching rollers adjacent to saidslot in the first roller, having flattened faces adapted to stand adjacent to and substantially parallel with each otherat one point in the rotation of the stretching rollers, said stretching rollers having adjacent to their flattened faces, corresponding smooth surface portions and adjacent to said smooth portions knurled surface portions, whereby when the ends of a blanket are between said flattened faces and the stretching rollers are rotated, the blanket ends may be first gripped between said smooth portions for permitting some slippage, and subsequently by the said knurled portions for proper stretching, the radia of the stretching rollers atthe parts having smooth" surfaces being slightly less than theirradia at their parts having knurled surfaces. Des Moines, Iowa, May 12,1921. I

j ERVIN E. STRAWN';

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