US1786188A - Method and apparatus for stretching fabrics - Google Patents

Description

Dec. 23, 1930. A. BOSSHARD 1,736,183

METHOD ANITAPPARATUS FOR STRETCHING FABRICS Filed July 7, 1928 IN V EN TOR.

' 15 scribed.

Patented Dec. "23, 1930.

' meane- UNITED STATES PATENT o Frce ARNOLD BOSSHARD, OF ARBON, SWITZERLAND, ASSIGNOR T SIR- J'AMES FARMER NORTON & COMPANY LEMITED, OF LANCASHIBE, ENGLAND, A BRITISH COMPANY METHOD AnnAPPARArUs FOR s'ran'rcnme FABRICS Application filed July 7, 1928, Serial No. 290,961, and in Germany Februai-y 3, 11928.

and useful method and device for stretching:

a web of. fabric in breadth. V Objects and advantages of the invention will be set forth in part hereinafter and in part will be obvious herefrom, or may be learned by practice with theinvention, the same being realized and attained by means 19 of. the instrumentalities and combinations pointed out in theappended claims.

The invention consists in the. novel parts, constructions, arrangements, combinations and improvements herein shown and de- The accompanying drawings, referred to herein and'constituting a part hereof, illustrate oneembodimentlof the invention and together. with the descriptiomserve to ex- 1 as plain the principles of the invention.

7 .Of the drawingsse- V Fig. 1 is a fragmenjary, vertical section of a chainless merce izing machine embodying the invention;

, Fig. 2 isa detail stretching and plan view of a broadroller embodying the .-invention 40 very thorough, efficient and evenly distrib:

uted stretching action, utilizing all the power of the machine; eliminatingthe warping of the tissue and displacement of the threads in the fabric and preventinga shoving effect by the stretching devices' with consequent injury. and disfiguring of thefabric.

The usual-apparatus forstretching a web of fabric in breadth, employed in machines 'ofthetype indicated, consists of a series of breads e chz ea oll r eac comprising. a

Fig. 3 is a diagrammaticshowingof the curvedaxle with a plurality of roller segments or cylindrical, members rotatively mounted and adapted to turn freely thereon.

The roller segments are ordinarily interlocked by clutching-teeth or by frictional engagement so that they turn together, and may be positively driven by suitable driving mechanism. The web of; fabric to be stretched ifn'breadth is progressed longitudinally through the'seriesrof rollers passing over each broad-stretching roller in sequence, the curvature of the axle causing the fabric to be stretched laterally as the web moves forwardly through the rollers. V V e r In the broad-stretching rollers at present employed, each roller segment or cylindrical section is of uniform diameter throughout its length and all the segments on the axle are of the same diameter, whereby any element of the periphery of a given segment is substantially parallel tothe part of the axle about which it rotates. Hence, each roller segment has the same peripheral velocity in a direct-ion perpendlcular to its respective portion of the axle, each segment being of the same diameter and having the same number of revolutions about the axle as every other segment As a result of this construction, the web of fabric in passing over the broadstretching rollers is not stretched evenly throughoutits width, but receives a different longitudinal and lateralstretching force at different points across the web, so that the fabric is warped or distor ed in the direction of the weft threads. V The reason for the warping or distortion of thefabric will be clear when it is considered that different parts ofthe web progressing through the series of broad-stretching rollers are subjected to different; stretching effects. The centraljportion of the web, which runs overthe center roller segment, issubjected to a forward progressing force proportional to the forward peripheral velocity of that seg-.

ment. Since the axle of the stretching roller is curved rearwa-rdly on both sides of the center, the forward'peripheral velocities of the roller segments on either side of the center segment willbe less than that of -the center segment, because, being-of the same diameter and turning with the same angular speed about an axis inclined to that of the center segment, the forward progressing force of the side rollers will be only a component of their peripheral velocity. In other words, the maximum peripheral velocity of each roller segment is not truly forward in the direction of progression of the web, but is in a. direct 1 perpendicular to the axis about which the n segment turns.

The effect of the hereinbefore-described differences in forward progressing force of the roller segments at different points along the curved roller is to feed the portions of the web at different speeds. The lateral edges of the web are progressed much more slowly than the center portion, and conse quently the forward movement of a weft thread is different at different parts thereof, so that the fabric is distorted, warped or pulled out of line in the direction of the weft thread. Since the broae-stretching rollers are usually ar 'anged in series, the warping effect is cumulative. each roller adding its displacing force to the progressing web. Of course, the warping only goes as far as the lasticity of the tissue will permit. The remaining unused power, or more properly, the difference in power at the different parts oi the roller, applies itself to shoving the fabric through the rollers, which further distorts the fabric and greatly injures and disfigures the cloth. Furthermore, due primarily to the displacement of the warp thread, the brezul-stretehing effect is greatly reduced and the mechanism does not realize its full eiiiciency in this direction.

The above-mentioned disadvantages and defects in the operation of the usual type of broad-stretching roller have long been recognized in the art and in order to remedy the results thereof, auxiliary mechanisms and arrangemeins nave been resorted to for restor ing the adjustn'ient of the threads in the fabric after removal from the broad-stretchmachine.

The present invention overcomes the d: advantages of the present ln'oad-stretcl-iing rollers and does away with the necessi y for auxiliary d vices for the purpose described. The present preferred embodiment of the invention, broadly considered. comprises a br l-strctchinq roller provided with'a plurality of roller ments, the diametersof the 'incnts being 11 that the power of all the nents, effective in the direction of the warp thread, is equally great. The diameters of the rollers acrease toward both sides of the axle in proportion to the radius. of the curve of the axle on which they rotate. In other words, all the segn'lents of the broadstretching roller of the present invention move the fabric in the warp thread direction with the same rapidity, so that the weft threads can no longer become warped.

By virtue of the present invention, not only are the injurious effects of the usual broadstretching rollers eliminated, but the actual stretching effect is much stronger, as the remaining power, or component of the stretching roller in the lateral direction can be really effective in the direction of the weft thread, which is not possible when the threads of the fabric are displaced as hercinbeforedescribed.

It will be understood that the fore oing general des/ 'iption, and the follmvn detailed description as well, are explanatory and exemplary of the invention but are not restrictive thereof.

Referring now in detail to the embodiment oft-he invention, illustrated by way of example in the accompanying drawings, Fig. 1 shows an exemplary embodiment of the invention as applied to the broad-stretching rollers of a chainless mercerizing machine, such for instance as that disclosed and described in my copending application, Ser. No. 119,137, filed June 28, 1926. It will be understood, however, that the embodiment shown is explanatory and illustrative but not restrictive of the invention, which may be employed in any kind of machine for handling fabric or the like.

The machine frame 1 is provided with a plurality of broad stretching rollers mounted on curved axles 2, suitably fixed in the frame and arranged sequentially in a substantially horizontal row, whereby they web of fabric passes through the machine from left to right, being sequentially subjected to the broadstretchiug effect of each roller. The roller segments 3, d, 11, 12, 13, 14: and 15 are mounted to turn on the axles, the curvature of the axle bringing the abutting ends of the roller segments into frictional engagement along the inner or concave side of the curve, whereby the segments are adapted to turn together to propel the web of fabric forwardly through the machine while stretching it in breadth.

Suitable driving mechanism may be provided for rotating the roller segments on the axles. As embodied, the driving gears 6 and 7 mounted on shafts 8 and 9 and driven from any suitable driving source, are adapted to mesh with gear wheels 10 at the ends of the axles. The gear wheels 10 of the axles are likewise adapted to intermesh with each othr, whereby all the broad-stretching rollers are operatively connected.

Referring now to the construction of the broad-stretching roller itself, the invention provides a plurality of roller segments rotatably mounted on the axle 2, the centrally disposed segment 3 being substantially a true circular cylinder of the same diameter throughout. The roller segments 4 on either side ofthe segment 3 are of varying diame-.

ter, comprising preferably frustra of a cone,

whose smaller base is substantially of the diameter of segment 3 and whose diameter is increased proportionately to the radius of the curve of the axle 2. That is, the diametric increase of the segment is proportional to the sharpness or rate of curvature of the particular axle on which it is mountedfThe roller segments 11 next in the lateral sequence outwardly from the center of the axle have bases substantially equal in diameter to that of the outer bases of segments 4, the diameters of segments 11 increasing along the axle in the proportion indicated. The remaining laterally disposed segments, 12, 13 and 14 likewise comprise cone frustra whose diameters increase toward the endsof the axle sequentially in the same proportion.

Referring now to the operation of the invention, under the turning influence of the driving mechanism, central roller 3 rotates with a forward peripheral velocity of the value V and progressesthe central portion of the web forwardly with a corresponding force, as indicatedin Fig. 3. The segments 15, at the extremities ofthe axle rotate with a peripheral velocity V which is exerted in a direction perpendicular to that portion of the axle about which section 15 revolves. There is consequently a resolved force C in the forwardly progressing direction. Ac-

cording to the invention, the diameters of seg- V ment 15, and of the intervening segments 11-14l are so proportioned that the forward 7 component C of the peripheral velocity and progressing force will always be equal to that V of circular roller segment Hence, there is provided a broad-stretching roller having a forward peripheral velocity and forward progressing force which is the same atrall points alongthe roller;

The vector C represents the breadthstretching eflect or power of the roller segment 15 in the lateral direction. It will be noted that this vector also increases laterally of the roller so thatthe breadth-stretching effect in the roller of the present inventionis much greater than that developed in the old type of roller where the roller segments were all of the same diameter.

The invention in its broader'aspects is not limited to the specific mechanisms shown and described but departures may be made therefrom within the scope of the accompanying claims without departing from the principlesv .ofthe invention and without sacrificing its chief advantages. r

What I claimis 1. A breadth stretching device for fabrics comprising a curved axle, a plurality of V roller segments of different diametersrotatively mounted on the axleffor progressinga web of fabric forwardly while stretching it in breadth, the diameters of said segments increasing progressively toward the lateral edges ofthe web of fabric whereby the roller segments are adapted to progress the web forwardly with substantially equal velocity grossing velocity substantially equal at all points along a transverse thread.

3. In a fabric stretching mechanism hav ing a plurality of curved-breadth-stretching rollers arranged in juxtaposed sequence whereby a web of fabric progresses under and over alternate rollers to be stretched in breadth as it progresses lengthwise, the coinbination'of conical roller segments on the curved axles of said roller members for imparting a substantially equal forward-progrossing force to the web at all points across theroller, and means for driving said'segments together. i

4. A breadth stretching device for a web I of-fabric comprising aplurality of rollers mounted on a curved shaft, the diameters of adjacent rollers increasing outwardly'from the smallest roll at the mid-portion of the shaft, the distances from the shaft to the pe riphery of each roller measured on lines parallel to the forward movement of the web being substantially equal.

5. A breadth-stretching device for a wet of fabric comprising a plurality of rollers V of different diameters mounted on a curved shaft and adapted to turn together, the diameters of the rollers'being so proportioned to their distances from the midsection of the shaft that the peripheral velocities of; the rollers in the direction of the web travel are substantially equal.

6. A breadtl1-tensioning device for a web of fabric comprising'a curved axle, a plurality of conoidal roller segments rotatively mounted thereon for progressing a web of fabric forwardly while stretching it transversely, the diameters of said'conoidal segmerits increasing progressively outwardly from a median point on the axle in such proportion that the forward component of the peripheral velocity of each segment is substantially equal, and means for rotating said segments together.

In testimony whereof, I have signed my name to this specification.

ARNOLD BOSSHARD.

ISO

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