US2695440A - Loom heald - Google Patents

Description

Nov. 30, 1954 M. M. TAYLOR 2,695,440

LOOM HEALD Filed Sept. 20, 1950 FIG. I

Q II n 2 s II u FIG. 2. FIG. 3.,

2o 7 2 M-M'TAYLOR 22 FIG. 4.

U d States Patent LOOM HEALD Matthew Michael Taylor, Spondon, near Derby, England, assignor to British Celanese Limited, a corporation of Great Britain Application September 20,1950, Serial No. 185,709

Claims priority, application Great Britain September 30, 1949 5 Claims. (Cl. 28-72) This invention relates to looms for weaving and is particularly concerned with the healds employed in looms for controlling the warp threads to form the shed.

Healds are commonly made from cotton yarns, the yarns used being generally of high quality cotton and made by doubling and redoubling fine yarns (e. g. 50s-l00 count) to impart strength and roundness to the resulting product. Each heald consists of a loop of yarn stretched between two parallel staves, which carry a series of healds constituting a heald shaft, and formed with or carrying an eye midway between the staves for the passage of a warp thread. After the yarn is formed into a series of loops (an operation known as knitting the healds) the healds are given several coatings of varnish while held stretched between two bars, and it is necessary that each coating should be stoved so as to dry it thoroughly before the next coating is applied. After each'stage of varnishing, healds that have been stuck together in the course of varnishing must be separated from one another, as by a combing operation and by brushing with a stiff brush to remove rough places where the healds have been separated from one another. The varnishing of the healds is thus a very expensive and time-consuming operation, and it is an object of the present invention to-provide a yarn for the making of coalescible fibres are preferably high tenacity filaments,

i. e. filaments which have been so stretched in the course of their manufacture as to impart to them a substantial degree of molecular orientation and consequently a high tensile strength. Thus there may be used continuous filaments produced by stretching filaments of cellulose acetate in the presence of moist steam or other agent adapted to facilitate stretching to 5, 10 or more times their original length and then saponifying the stretched filaments. 0r again, continuous filaments of a high-melting synthetic linear polymer, such as a polyamide, that have been oriented by drawing can be used, either as non-coalescible filaments in association with other fibres that can be coalesced without afiecting the high-melting filaments, or as filaments which can themselves be partly coalesced. An advantage of using continuous filaments is that they can be used in the form of a heavy yarn having very little twist, whereby the full advantage is obtained of the tenacity of the continuous filaments, while the resulting heald yarn is very limp and flexible and is easy to knit.

The different fibres of which the yarn is made can be associated in the yarn in any appropriate way. Thus, singles yarns may be made from a mixture of fibres of non-coalescible substance with fibres of a coalescible substance, and these singles yarns may be used as such, or doubled with one another or with yarns consisting wholly of non-coalescible fibres, to form the yarn from which the heald is made. As previously stated, however, the yarns are preferably made of continuous filaments, for which purpose multi-filament yarns of a coalescible substance may be doubled with multi-filament yarns of a non-coalescible substance and the resulting doubled yarns may be further doubled or cabled with one another to give a final yarn that is round and compact, proper- Y ties that are highly desirable in heald yarns.

healds, by the use of which this operation can be eliminated.

-'According to the present invention amethod of making healds for'use in weaving looms comprises'forming healdsfrom yarns of which some or all of the fibres consist of a substance that is coalescible'by a coalescing treatment and, after the healds are formed, subjecting them to "said coalescing treatment so that a part of the substance of the yarn is coalesced to form a continuous coating over the yarn constituted by the uncoalesced part of the fibres. If the fibres consist wholly of a coalescible substance the coalescing treatment must be closely controlled so that only part of the fibres are coalesced. It is preferred, therefore, that a part only of the fibres should be coalescible, the treatment being such as to coalesce this part completely and to leave the remaining fibres uncoalesced so that the control of the treatment is less critical.

By means of the invention the protracted operation of repeated varnishing, drying and brushing the healds to separate them is replaced, as a method of forming a coating over the healds, by the relatively rapid operation of coalescing the coalescible fibres of the yarn from which the healds are formed (with a single brushing operation if required), so that the cost of producing the healds is substantially reduced. At the same time the reduction in strength of the heald yarn by knotting it in the course of the heald knitting or other heald-forming operation is reduced since, by reason of the increased. diameter of the yarn due to the presence of the coalescible fibres, the yarn is notturned round so sharp aradius at the knots as it would be if the coalescible fibres were not present.

Most conveniently the coalescible part of the yarn consists of fibres 'of cellulose acetate or other organic derivative of cellulose while the'non-coalescible part consists of fibres of regenerated cellulose. Both thecoalescible fibres and the non-coalescible fibres are most conveniently in the form of continuous filaments, although for the latter purpose, if desired, cotton or worsted yarns can beiused..- .Contmuous filaments used as the non- An alternative method of associating coalescible and non-coalescible continuous filaments to give a round and compact product is to enclose a core consisting wholly or principally of non-coalescible filaments within a sheath consisting wholly or principally of coalescible filaments. The sheath of coalescible fibres can be applied to the core by means of a wrapping or lapping operation of the kind used for applying insulating yarns to electrical conductor wires. Preferably a double covering of coalescible yarn is applied, the two layers being lapped in opposite directions and applied to the core in a single lapping operation. The lateral pull of the lapping yarn as it is applied to the core draws the core into a round and compact cross-section such as is desirable in heald yarns. Alternatively the covering of coalescible yarns may be applied by a braiding operation which will also have the effect of producing a round and compact cross-section and is of further advantage as giving a product that is more resistant to abrasion in the operation of knitting the healds. Indeed, the covering itself can be formed by braiding a number of continuous filament regenerated cellulose yarns into a braid of circular section. When this is done an inner core of coalescible yarn can be included within the regenerated cellulose braid so as to ensure very thorough penetration of the coalesced substance throughout the finished healds.

The weight of the non-coalescible part of the heald yarn can be made to correspond to the weight of cotton yarn that would be employed for the same purpose. Thus, while cotton yarns employed as heald yarns may range, say, from 20/40s count down to 12/ 80s count, they may be replaced by heavy low twist yarns of continuous regenerated cellulose filaments correspondingly ranging from about 2650 denier down to about 800 denier. However, on account of the greater strength of low-twist continuous filament yarns, especially when high tenacity filaments are employed, it may be convenient to use an assemblage of non-coalescible filaments of lower weight and thickness than the cotton yarn that would be employed for the same purpose.

While cellulose acetate yarns are the most convenient for use as the coalescible part of the heald yarn of the present invention, yarns of other coalescible materials may be employed. Thus yarns of other cellulose derivatives can be used, c. g. of other organic esters or mixed esters of cellulose such as cellulose propionate, cellulose butyrate, celluloseaeetate-propionate and cellulose acetate-stearate, or cellulose ethers such as ethyl cellulose. Or again, yarns of polyvinyl compounds can be used, e. g. of a co polynierof yinylvchloride"with vinylidene chloride vinyl. acetate oracrylonitrile;

The heald yarns can be knitted into :healds:in the usual way, i. 'e. byformingtwo' or: more of theyar'ns into a connected series of'spaced healds,.in-'which. case additional yarns having a content-of coalesciblehfibres can be employed to forrnbraidedorknitted ridge :bands of substantial weight and strength at the top andbottom of the series. Alternatively,-the=yarns=canibe knotted into in dividual healdsfor use as slider healds, each having a heald eyein-the middle anda loop above and below to receive the heald staveswon which the healds are slid. Or again, after coalescence -a knitted series of healds can be cut through the ridge bands at'the'top and bottom to separate them into individual healds.

The coalescing of. the coalesciblefibres after'the forming of the healds can conveniently be effected by immersing the healds while stretched between two bars inasolvent for the substance of the coalescible fibres, alone or in admixture with a diluent to moderate the solvent action. Thus, in the case of cellulose acetate fibres, the healds may be dipped in a mixture of acetone and ethyl alcohol. Alternatively, however, the fibres may be coalesced by the application of heat, especially if a suitable plasticiser is included in the substance of the fibres so as to facilitate fusion. The ridge bands-' rnay be further treated, especially if they are to be severed to produce individual healds, by running a heavy roller along them While the coalescible fibresare still soft so as toweld and compact together their component parts.

The following are: given as examples of heald yarns in accordance with the present invention, in each case to match a cotton heald yarn of 16/60s cotton count (4 fold 4 fold).

Example 1 Three low-twist ends of continuous filament yarn, each of 225 denier, two of which consist of cellulose acetate filaments that have been stretched in the presence of moist steam to times their original length and then saponified, and the third of unsaponified cellulose acetate filaments, are doubledtogether with 18 turns per inch 8 twist. Three of the resulting doubled yarns are further doubled together withlO-tu'rns' per inch of'Z twist, to give a finished yarn of about 2100 denier, of whichjthe regenerated cellulose element is about equal in weight to the cotton yarn to be replaced. The yarn can be knitted into healds at a spacing of healds'pe'r intih, the heald eyes being formed in the yarn by knotting at the mid-point of each heald. The resulting healds, while stretched on a pair of rods, aredipped in a mixture of equal parts by volume of acetone and ethyl alcohol and allowedtndry. The acetone causes the cellulose acetate of the yarn to coalesce, and to squeeze outunder the tension in the healds so as to form a continuous coatingover the heald yarn. The healds are then brushed with a stilt brush dipped in a solution of 10 percent by weight of paraffin Wax in the above mixture which re-soften's the coating on the healds. The brush acts as a comb to part any healds that are stuck together, smoothing'out any sharproughedges formed on parting and leaving the healds with a smooth, uniform and continuous coating of cellulose acetate. The wax in the liquid with which the healds are brushed is left as a light coating on the surface of the healds, which prevents them sticking together again if they should come in contact with one another. The brushing operation which is made easier by the fact that the cellulose acetate originates from the body of the heald y'arn itself and is not applied externally to the healds, needs to' be carried out once only and not repeatedly as in the case of varnished healds. In the resulting healds, the knots forming the heald eyes are small, the low twist yarns apparently bedding into one another under the tension inth'e healds as the cellulose acetate softens, and giving'rise to a smooth eye offering little hindrance to the passageof a'warp thread.

Example 2 To provide a heald havingaheaviercoating of coalesced material, four ends of continuous filament yarn, each of 225 denier, three of which consist of unsaponified cellulose acetatefilamentsand the fourth of stretched and saponified cellulose acetate filaments, are doubled together with 8 turns per inch Stwist. Four*of-the resulting doubled yarns are further doubled together with 6 turns per inch Z twist to give a" finished yarn of about 3600 denier of which the regenerated cellulose element constitutes one quarter, i. e.':substantially less than the weight of the cotton yarn to be replaced. The resulting yarn is knitted into healds at aspacing of 15-20 healds per inch and the knitted healds are treated as in Example 1.

Example 3 A low twist continuous filament heavy singles-yarn is used having a total denier of "1300 (i. e. rather'le'ss 'than the weight of the cotton yarn replaced) and made of stretched and saponified cellulose acetate filaments. The heavy singles yarn is lapped in a single operation with 4 ends of denier cellulose acetate yarn lapped in one direction and a further 4 ends of 75 denier cellulose acetate yarn lapped in the other direction at 12-15 wraps per inch. Alternatively, 3 ends of. denier-yarnican. be used for lapping in either orboth directions. The result ing yarn has a total weight ofabout .2200. denier, and can be used in the manner described in Examplev 1.

The form of the healds resulting from carrying .out the above examples and themanner in which the components of the heald yarnsare associated, are shown diagrammatically in theaccompanying drawings in which:

Figure 1 is a section of .the length of a heald shaft, and,

Figures 2, 3 and 4 are schematic representationsof' the methods of making the heald yarns of Examples 14 respectively.

Referring to Figure 1, the. bars on which the healds are threaded are indicated at.-4 and 5, .thehealds. beinglformed from two continuous yarns 6 and 7. The bights formed in the yarn 6 are knotted into loops or heald'eye's- 8 through which the bights ofthe yarns 7,v pass. Aboveand below the bars.4 and 5 respectively, theyarns 6:1and 7 are knitted into ridge bands 9 and 10 which,.rafterr.the healds have been dipped. inthe manner described inthe examples and While the cellulose acetate fibresarestill soft, are compacted by running aheavy roller. along them so as to weld together their component parts.

In Figure 2, which is:illustrative.ofaExample1,.the:individual yarns of stretched-and saponified.continuous'filaments of cellulose acetate are indicated at 11, while 12 are the individual unsaponifiedcellulose acetate yarns. The unsaponified yarns 12 are showntby thicker linesthan the stretched and saponified yarns 11 in order to distinguish them, although in fact,.as stated in the example, the-yarns 11 and 12 are of thesame weight. .Two yarns 11 and. one yarn 12 are doubled together to form the doubled yarns 13, three of which are further doubled to'form thetfinal I heald yarn 14.

In Figure 3, illustrative of ExampleZ, the stretched and saponified cellulose acetate yarns are shown atLI S while the thicker lines 16 represent'the unsaponified'cellulose acetate yarns, these yarns being doubled together to form four doubled yarns 17 which in turn'are. further doubled to form the heald yarn 18.

In Figure4, which illustrates ExampleB, 19 .iszthelow twist continuous filament heavy singles yarn, i20-arefthe four 75 denier cellulose acetate yarns which'are first lapped over the yarn 19, and ZIare-fourfutther 75..denier cellulose acetate yarns which are lapped inthe opposite direction over the yarn 20 to give rise to the heald yarn 22.

Having described my invention, what-I desire to 'secure by Letters Patent-is:

1. A method of making healds for use-in weaving looms, said method comprising forming the healds from yarns of which at least one-third by weightof the fibres (consist of a substance thatis coaleseible by a: coalescing treatment and, after the healds. are formed, subjecting thetn -to said coalescing treatment so that-a part of the substance of the yarn is coalesced to form acontinuous. coating over the yarn constituted by the uncoalescednpart of the; fibres.

2. A method accordingto claim lwherein the yarn is a composite yarn formed from a'number ofvindividualyarns of which some consist-wholly of a coalesciblersubstance and the remainder consist wholly ofanuucoalescb ble substance.

3. Method according to claim 1 comprising forming-the healds as a closely. spaced-series ofhealds, and brushing the healds, .after coalescence; with a; liquid which is-a solvent for the coalescible material so as to separate any healds that stick together.

4. Method according to claim 3 comprising brushing the healds with a solution of a wax in a solvent for the coalescible substance.

A method of making healds for use in weaving looms, said method comprising forming the healds from composite yarns each built up of a number of individual yarns of which at least one-third by weight consist wholly of fibres of a substance that is coalescible by a coalescing treatment while others of the individual yarns consist wholly of fibres that are inert to said coalescing treatment, subjecting the healds after they are so formed to said coalescing treatment so that a part of the substance of the composite yarn is coalesced to form a continuous coating over the yarn constituted by the uncoalesced part,

and brushing the healds, after coalescence, with a solution of a wax in a solvent for the coalescible substance.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,045,684 Andrews June 30, 1936 2,125,278 Andrews et al Aug. 2, 1938 10 2,313,058 Francis Mar. 9, 1943 2,380,003 Whitehead July 10, 1945 2,491,396 Seckel Dec. 13, 1949 FOREIGN PATENTS 15 Number Country Date 552,225 Great Britain Mar. 29, 1943 874,307 France Apr. 27, 1942

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