US2141038A - Triple warp ladder web - Google Patents

Description

Dec. 20-, 1938. a. F, FRENCH TRIPLE WARP LADDER WEB Filed Aprii 22, 1938' INVENTOR. GEORGE E FRENCH ATTORNE Patented Dec. 20, 1938 TRIPLE WARP LADDER WEB George Frederick French, Manchester, England, assignor to Thomas French & Sons Limited, Manchester, England, a corporation of Great Britain Application April 22, 1938, Serial No. 203,583 n Great Britain December 22, 193':

17 Claims. (Cl. 139-384) This invention relates to ladder web, as, for

example,-such as is used for supporting the laths of Venetian blinds or for holding pieces of cork or the like in sun helmets. Ladder web of the character dealt with herein has long been known and used, especially for Venetian blinds. ladder webconsists essentially of two outer bands with narrower cross-straps between said outer bands at regular spaced intervals. The said cross-straps are alternately near one or the other edge of said outer bands.

Originally, it was customary to weave each of said outer bands and the cross-straps separately Such and then cut the same to suitable lengths and,

sew the parts together, by hand. Later,'a loom was developed for weaving both the outer bands and the cross-straps simultaneously and securing the parts together in their final positions. This method of manufacture originated many years ago and is described in British Patent No. 229 of 1869. This method of manufacture has been in universal use ever since the date of said patent and has continued in use without any substantial modification up to the present invention.

In the said previously known make of webbing, the connections of the cross-straps with the outer bands were relatively short, about half to three quarters of an inch for the largest size of webbing, due to the use of a single set of warps for each row of cross-straps, and due also to the spacing of the cross-straps requiring-to be such as to allow of the blind laths overlapping, to shut out the light, when in use. Again, the connections of the cross-straps warps with the outer on the outer band warps, and binding them thereto by a few of the weft threads of the bands. With such short connections, and owing also to the strap warps being composed of fine thread, it

has been a common fault for the strap warps to pull out, or break away from the outer bands, in

use. I

The employment of fine warps threads was mainly to prevent bulging or distortion of the edges of the outer bands adjacent the points where the cross-straps were connected, and for a like reason the cross-straps were connected at a material distance from the edges of the bands. The cross-straps were bound to the bands along rathernarrow areas and the bindings-in were visible from the outside, especially in the case of a twill weave of band.

- The present invention is intended and adapted to. overcome the disadvantages of the prior method of manufacturing ladder web and to probands were effected by superimposing the same,

1 which were used for the outer bands andthe gether but at the same time will afford the necesvide a construction in which the cross-straps are more firmly united with the outer bands, in which there is no bulging of the edges of said bands even when the cross-straps are located up to the very edge of said bands. 5 It is a further object of the present invention to provide a construction in which there is no blemish of the twill weave where used, in which thecross-straps may be short and lie close tosary firmness of connection with the outer bands, in which the cross-straps need not be staggered but may be in a single row, superimposed one above the other.

It is a still further object of the present invention to provide a method of weaving ladder web in which the cost of productionis greatly reduced, in which coarser threads may be utilized in the weaving, from which narrow web will result, and which is adaptable for use in producing weftless ladder web of great strength and utility.

In accordance with the present invention, I do not provide four sets of warp threads, two sets of other two sets of which were used for the crossstraps, as was customary in the prior art. On the other hand, I provide essentially only three sets of warp threads, each of which in succession forms a length of an outerband, them a cross-strap, and then a corresponding length of the opposite outer band. Then saidwarp threads cross over into the first mentioned outer band and weaving is continued in the same cycle, namely, said threads forming alength of the said first named outer band,then. the cross-strap, and then the length of said opposite outer band, and so on. The two cross-straps described are not adjacent to each other but there areinterposed therebetween two other cross-straps formed from the other two sets of warp threads herein described.

The second set of warp threads, for purposes of illustration, begins at or about. that area of the first named outer band at which the first mentioned warp threads leave the same to form a cross-strap. Said second set follows along after the first named set, forming successively a length of outer band, across-strap, a: length of the opposite outer band,-and a cross-overto the first mentioned band. The third set of warp threadsv follows the first two named sets in exactly the same order, starting, for example,-at the area where the second set of warp threads begins to form a cross-strap and forming successively a 66 threads outlined above, the outer bands are woven in their entirety. In addition, one or more weft threads may be'provided for weaving the cross-straps. However, in a preferred form, the cross-straps are weftless and therefore no .additional weft threads are necessary without any sacrifice of strength or utility.

However, in actual practice, it is not possible to make perfect ladder web with only three sets of warp threads. Since, in the usual ladder web the adjacent cross-straps are in staggered relation in two rows, there is usually provided three sets of warp threads for each row of cross-straps. In addition, there is ordinarily provided ground or base warp threads for each of the outer bands which do not cross over but are woven contin uously into their respective bands.

In the accompanying drawing, constituting a part hereof and in which like-reference characters indicate like parts, Fig. 1 is a diagrammatic view looking from the side of a length of ladder web made in accordance with the prior art. The outer bands of the ladder web are shown a greater distance apart than is customary in order I to clarify the construction;

Fig. 2 is a similar diagrammatic view of a length of ladder web made in accordance with the present invention. There is no showing of the second set of cross-straps illustrated in Fig. 1 in order to clarify the showing and each of the three sets of warp threads are illustrated differently in order that the course thereof maybe clearly followed; and

Fig. 3 is a diagrammatic plan view of a piece of ladder web made in accordance with the present invention.

In the prior art as illustrated in Fig. 1, it was customary in the weaving to produce two outer bands I and 2, respectively, arranged in parallel relation. One of the sets of cross-straps con sisted of a binding-in 3 formed by attachinginthe loom of a section of the cross-strap into outer band 2, said binding-in being superimposed upon the outer band and increasing the thickness at said point. From the binding-in, a cross-strap 4 passed over to outer band I and a similar binding-in 5 was formed on the inner surface thereof. This binding-in of course increased the thickness of the band at said point. Thereafter, there was a cross-over 6 onto outer band 2, then a similar binding-in I, a similar cross-strapii, and a similar binding-in 9, and so on, repeating the cycle. The above described set of cross-straps was, say, located near the front edges of the outer bands and a second set of cross-straps was formed near the opposite sides of said outer bands. In Fig. 1 this is illustrated by the binding-in III on outer band 2, the cross-strap II, the binding-in l2 on the opposite outer band I, the cross-over l3, and the binding-in ll on outer band 2, the cross-strap l5, and so on, repeatingthe cycle.

In Fig. 2 I have illustrated diagrammatically the radically different method of making ladder web in accordance with the present invention. In order to form the lower outer band, a weft thread I6 is provided which continuously formssaid outer band cooperating with a series of warp threads II. The weaving of threads l6 and I1 forms a predetermined section of the lower outer band. Thereafter, the warp threads leave said outer band, forming a cross-strap I8, and then entering into the upper outer band at l9, being woven into the same by weft thread 20. After a predetermined length thereof has been woven into said upper outer band, the warpthreads cross over, as shuwn at=2l, and weaving is continued with weft thread IE to form a predetermined section 22 of the lower outer band. The cycle then is repeated.

A second set of warp threads 23, shown crossing over from the upper to the lower outer band, enters the lower band at approximately the transverse line where threads l8 leave the same to form a cross-strap. Threads 23-are interwoven with weft thread IE to provide a predetermined length 24 of the lower'outer band. Thereafter the warp threads, in passing to the upper outer band, form the cross-strap 25 and they are woven' into the upper band by means of weft thread 20 to form a length 26 of the upper outer band. Then said warp threads cross over, as shown at 21, again entering the lower outer band and being woven into the same by weft thread It. The cycle is, of course, repeated.

The third set of warp threads 28 is woven into the upper outer band for the length 28 beginning at the transverse line approximately where warp threads 23 left the. same to cross over. when the weaving-in of warp threads 28 reaches the point where warp threads l8 enter the upper o'uter band, .said threads 28 cross over, as shown at 29, to the lower outer band at approximately the point where warp threads 25 leave the same to form a cross-strap. They are woven into the a lower band with weft thread ii for a predetermined length 30. They leave said lower outer.

band at approximately the area where the crossover warp threads 2| enter said lower outer band and form the cross-strap 3| entering the upper outer band at approximately the area where cross-over threads 21 leave the same. They are then woven into the upper outer band for a predetermined length 32, the cycle is, of course reever, a second set alternating with the described set may be made as is common practice. This is accomplished by dividing the sets of warp threads into two parts whereby only part thereof go through the cycle shown in Fig. 2 and the other part may alternate therewith along the opposite edges of the outer bands. Furthermore, if desired, a central space may be left between the two setsof cross-straps. In Fig. 3 I have illustrated a form of ladder web made in accordance with the present invention. Section A is that formed, for example, by the weaving-in of warp threads II. Section B is formed by the weaving-in of warp threads 24, and Section C is formed by the weaving-in of warp threads ll. Thereafter, the cycle repeats itself. At X is shown the area at which the warp threads cross over to form' the cross straps.- It will be noted that this forms only one side of the ladder web. The other side thereof maybe similarly formed with Sections A, B and C of outer bands with cross-straps X alternating with cross-straps X.

come to approximately the outer edges of the outer bands. Ihe'sectiomA, 3,0 andthelike may be of plain weave or twill weave, and-when they are of plain weave it is desirable to have the section Y of twill weave for appearance sake. It will be noted that each of the sets of warp threads forms one outerband, a cross-strap, and the op-.

posite outer band, and the cycle continues indefinitely. This isa construction which is entirely different from that used heretofore and which has many advantages thereover. Because of the long weaving-in area into the outer bands, the cross-strap ismuch stronger because said weaving-in is several times that previously used. This makes certain that the cross-straps cannot pull out under severe use and makes more practical a weftless cross-strap. Since the weave of the outer bands is uniform, there do not appear any unsightly binding-in areas. It is possible by the use of the present invention greatly to increase the production of a loom for various reasons, as, 'for example, because coarser weft threads may be used, less picks are required, double threads may be. utilized'in the shuttle,-and only three. sets of warp threads are necessary in place of four.

There may be obtained any desired lap-over of the laths because the spacing of the cross-straps can be very easily changed. It also becomes practical to make narrower outer bands with the cross-straps close to the edge and even without any staggering thereof.. In place of at least some of the warp threads, I may use braid, cord, or tape which are bound-in to form the cross-straps and at least part of the outer bands. It is feasible to use plain weave instead of a twill, particularly for the narrower outer bands in order to give a stronger binding-in, since there are several times as many crossings of the warp and weft threads in the plain weave. .placed much closer together than heretofore, since a firm connection thereof into the outer bands is obtained, something which was impossible by the prior art method. The cost of pro- 'ductionv is, of course, greatly reduced. It is, of

course, understood that the cross-over from 'one' ing-in the strap warps the coarser yarns can be used without causing any bulging of the bandin'gs where the strap connections are made. Alternatively, ordinary fine 'warp may be used, and

. reliance placed solely on the new method of uniting the straps with the bandings to obtain the said advantages. Owing to the improved mode of uniting the cross-strap warps with the bandings,

the cross-straps may lie nearer the edges of the bandings without causing bulging of such edges, and by weaving them as part of the bandings, the joinings will not show through and the bandings maybe of the usual twill weave, with consequent advantage in appearance. the increased strength of the bindings-in, the

-webbing and cross-straps may be made narrower than heretofore, andthe cross-straps may also lie at shorter distances apart to suit narrow laths. The cross-straps may all lie in one row, and to allow them to lie at short distances apart, the free warps may extend through the next crossstrap and afterwards he cut away. When arranged in two rows, the rows will usually be The cross-straps may be.

And, owing to spaced apart to allow the usual blind cord to pass between, and when all arranged in one row, the said cord will be connected to the blind laths at a point beyond the webbing.

Although I have described my invention set- .ting forth a single embodiment thereof and have indicated a few variations therein, it will become apparent that there are many ways of carrying out the principal idea involved. The idea resides in the use of a minimum of three sets of warpv threads which form successively an outer band, a cross-strap and the opposite outer band, but it is, of course, understood that additional sets of warp threads may be utilized within the scope of the invention. Also, some warp threads may be provided which do not cross over at all but which continue to form but one of the outer bands. These and other changes in the details of my invention may be made within the spirit thereof, and the scope of my invention is .not to be limited except by the claims appended hereto.

What I claim is:

1. In ladder web including two outer bands and having cross-straps woven therein andspaced a given distance apart, the improvement which comprisesa plurality .of sets of warp threads woven with weft thread in each of the outer bands, each set forming successively a section of an outer band equal in length to said given distance, a cross-strap, a section of the opposite outer band equal in length to said given distance, a crossover, a section of said first outer band equal in length to said given distance.

2. In ladder web including two outer bands and having cross-straps woven thereinand spaced a given distance apart, the improvement which comprises a plurality of sets of warp threads woven with weft thread in each of the outer bands, each set forming successively a section of an outer band equal in length to said given distance, a cross-strap, a section of the opposite outer band equal in length to said given distance, a cross-over, a section of said first outer. band equal in length to said given distance, and a cross-strap, the latter having at least one othercross-strap interposed therebetween.

3. In ladder web including two outer bands" and having cross-straps woven therein and spaced a given distance apart, the improvement which comprises a plurality of sets of warp threads woven with weft thread in each of the outer bands, each set forming successively a sec tion of an outer band equal in length to said iven distance, a cross-strap, a section of the opposite 'outer band equal in length to said given distance, a cross-over, a section ofsaid first outer :band equal in length to said given distance, each set of warp threads then crossing over and repeating the aforesaid arrangement. 4. In ladder web including two outer bands and having cross-straps woven therein and spaced a given distance apart, the improvement which comprises three sets of warp threads woven with weft thread in each of the outer bands, each set forming successively a section of an outer band weft thread in each of the outer bands, each set 7 !orming successively a section of: an outer band- ,10 and having cross-straps woven therein and spaced a given distance apart, the improvement which comprises a plurality of sets of warp threads woven with weft thread in each of the outer bands, each set forming successively a section of one side of an outer band equal in length to said given distance, a cross-strap, a section of the cor-' responding side of the opposite outer band equal in length to said given distance, a cross-over, a section of said first outer band equal in length to said given distance,

7. In a ladder web including two outer bands and having cross-straps woven therein and spaced a given distance apart, the improvement which comprises a plurality of sets of warp threads woven with weft thread in each of the outer bands, each set forming successively a section of one side of an outer band equal in length to said given distance, a cross-strap, a section of the 'corresponding side of the opposite outer band equal 80 in length to said given distance, a cross-over, a section of said first outer band equal in length to said given distance, a second similar plurality of sets of warp threads woven with weft thread in each of the outer bands and forming successively a section of the outer side of said first outer band, a cross-strap, a section of the corresponding side of the opposite outer band, and a crossover.

8. In ladder web including two outer bands 40 and having cross-straps woven therein and spaced a given distance apart, the improvement which comprises three sets of warp threads woven with weft thread in each of the outer bands, each set forming successively one side of a section of an outer band equal in length to said given distance, a cross-strap, a section of the corresponding side of the opposite outer band equal in length to said given distance, a cross-over, a section of said first outer band equal in length so to said given distance.

9. In ladder web-including two outer bandsand having cross-straps woven therein and spaced a given distance apart, the improvement which comprises three sets of warp threads woven with iweft thread in each of the outer bands, each set forming successively one side of a section of an outer band equal in length to said given distance,

a cross-strap, a section of the corresponding side of the opposite outer band equal in length to said given distance, a cross-over, a section of said first outer band equal in length to said given distance, a second similar plurality of sets of warp threads woven with weft thread in each of the outer bands and forming successively 'a section 68 of the other sideof said firstouter band, a crossstrap, a section of the corresponding side of the opposite outer band, and a cross-over.

' '10. In ladder web including two outer bands and having cross-straps woven therein and 70 spaced a given distance apart, the improvement which comprises a plurality of sets of warp threads woven-with weft thread in each of the outer bands, each set forming successively a section of one side of an outer band equal in length to said given distance, a cross-strap, a section of straps extending to substantially the edges of said the corresponding side of the opposite outer band equal in length to said given distance, a crossover, a section of said first outer band equal in length to said given distance, a second similar plurality of sets of warp threads woven with'wett 5 thread in each of the outer bands and forming successively a section of the otherside of said first outer band, a cross-strap, a section of the corresponding side of the opposite outer band, a cross-over, and an additional set of warp threads l0 constituting a central portion of each outer band, the latter warp threads remaining continuously in their respective bands.

11. In ladder web including two outer bands and having cross-straps woven therein and. 15

spaced a given distance apart, the improvement which comprises three sets of warp threads woven with weft thread in each of the outer bands, each set forming successively one side of a section of an outer band equal in length to said given D distance, a cross-strap, a section of: the corresponding side of the opposite outer band equal in length to said given distance, a cross-over, a section of said first outer band equal in length to said given distance, a second similar plurality 25 of sets of warp threads woven with weft threads in each of the outer bands and forming successively a section of the other side of said first outer. band, a cross-strap, a section of the corresponding side of the opposite outer band, a cross-over, and an additional set of warp threads constituting a central portion of each outer band, the latter warp threads remaining continuously in their respective bands. 12; In ladder web including two outer bands and having cross-straps woven therein and spaced a given distance apart, the improvement which comprises a plurality of sets of warp threads woven with weft thread in each of the outer bands, each set forming successively a section of 4( an outer band equal in length to said given distance, a cross-strap; a section of the opposite outer band equal in length to said given distance,

a cross-over, a section of said first outer band equal in length to said given distance, said cross- 4| str ps being weftless.

13. In ladder web including two outer bands and having cross-straps woven therein and spaced a given distance apart, the improvement which comprises three sets of warp threads woven with g weft thread in each of the outer bands, each set forming successively a section of an outer band equal in length to said given distance, a crossstrap, a section of the opposite outer band equal in length to said given distance, a cross-over, a I section of said first outer band equal in length to said" given distance, said cross-straps being weitless.

14.- In ladder web including two outer bands and having cross-straps woven therein and I spaced a given distance apart,-the improvement which comprises a plurality of sets of warp threads woven with weft thread in eachof the Y outer bands, each set forming successively a section of an outer band equal in length to said given distance, a cross-strap, a section of the opposite outer band equal in length to said given distance, a cross-over, a section of said first outer band equal in length to said given distance, said crossouter bands.

15. In ladder web including two outer bands and having cross-straps woven therein and spaced a given distance apart, the improvement which comprises three sets of warp threads woven 1 aiupas,

with weft thread in each of the outer bands, each set forming successively a section of an outer band equal in length to said given distance, a cross-strap, a section of the opposite outer band equal in length to said given distance, a crossover, a section of said first outerband equal in length to said given distance, said cross-straps extending to substantially the edges of said outer bands. 7,

16. In ladder web including two outer bands and having cross-straps woven therein and spaced a given distance apart, the improvement which comprises a plurality of sets of: warp threads woven with weft thread in each of the outer bands, each set forming successively'a section of one side of an outer band equal in length to said given distance, a cross-strap, a section of the corresponding side of the opposite outer band equal in length to said given distance, a crossover, a section of said first outer band equal in length to said given distance, a second similar plurality of sets of warp threads woven withweft thread in each of the outer bands and forming successively a section of the other-side 01' said first outer band, a cross-strap, a section of the corresponding side of the opposite outer band, and a cross-over, said cross-straps extending respectively to an edge of said outer bands.

17. In ladderweb including two outer bands and having cross-straps woven thereinand, spaced a given distance apart, the improvement set forming successively one side of a section of an outer band equal in length to said given distance, a cross-strap, a section of the corresponding side of the opposite outer band equal in length to said given distance, a cross-over, a section of said first outer band equal in length to said given distance, a second similar plurality of sets of warp threads woven with weft thread in each of the outer bands and-forming successively a section of the other side of said first outer band, a cross strap, a section of the corresponding side of the opposite outer band, and a cross-over, said crossstraps extending respectively to an edge of said i outer bands.

GEORGE FREDERICK FRENCH.

which comprises three sets of warp threads woven with weft thread in each of the outer bands, each

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