Chapter II.

Chapter II.Looms Should Be Adapted to Make a Wide Variety of Goods—Take-Up and Let-Off Motions—Making the Rubber Warps for Different Classes of Web—Importance of Uniform Tension—Defects from Uneven Tension and Chafing of Threads

Looms Should Be Adapted to Make a Wide Variety of Goods—Take-Up and Let-Off Motions—Making the Rubber Warps for Different Classes of Web—Importance of Uniform Tension—Defects from Uneven Tension and Chafing of Threads

The greatest care is necessary in planning out the details of the harness. On account of the great length it becomes necessary that everything possible be done to avoid any chance of warping or sagging, for the least irregularity which may be developed will of course interfere with the evenness of the shed. The harness frames must be made of the very best stock obtainable, thoroughly seasoned, and absolutely straight grained. Each frame must be supported at regular and frequent intervals by stays or supports mortised in the runners. These stays are slotted at top and bottom to receive the heddle bars and keep them accurately in line, and thus prevent them from catching on the neighboring harness during the operation of the shedding process.

It is necessary also that the top and bottom heddle bars be accurately spaced so as to allow proper freedom for the heddles to ride easily on the bars, and thus avoid any binding of heddles which would have a tendency to crowd the warp stock together and prevent clearance of the shed. Steel heddles are preferable to ones that bend and twist more or less and get out of alignment. They are made from tempered steel which is very flexible and they have round cornerless eyes that cannot possibly catch or chafe the warp threads. They adjust themselves automatically to the frame and cannot twist or bend while at work, and are made to accommodate themselves to every conceivable kind of goods.

In installing looms for narrow elastic fabrics it is advisable to make ample provision for creeling the warps necessary for the different fabrics which may from time to time be required. In the manufacture of the light single cloth garter webs, not more than two warps to the piece are required, a face warp and a gut warp, and the temptation to save a little in the initial cost possibly may suggest a limitation of creel spaces to immediate requirements. Added expense may seem for the time being an unnecessary burden. But very soon there may arise a call for other goods which cannot be made within the limitations of the two bank creel; therefore changes become necessary which are generally much heavier than first cost would have been.

Nothing less than a five bank creel should be installed. Many times the availability of six banks has solved knotty problems of warp division to care for the various weaves and materials employed in some constructions. If the entire capacity of the larger creel is not required when first starting it will not be necessary to clothe all of it with levers, buttons, etc., which may be procured later. But by all means ample provision should be made for the full frame work and supporting rods for same.

Another important consideration is to make proper provision for a reliable take-up motion, so that the goods may be taken away from the reed while weaving without any liability to variableness. This liability was present in many of the earlier looms and exists in some of the millstoday. The old-time fine ratchet gear, even when provided with a number of pawls, is always liable to erratic picking, which alone will ruin an otherwise perfect piece of goods and materially change the cost of manufacturing. A slight irregularity of picking may not be discernible in non-elastic goods, which will be satisfactory so long as the variableness is not easily seen and a reasonable average of picks per inch is maintained. But in elastic goods, where the contraction takes place after they leave the press rolls, every irregularity is revealed and intensified so there is no room to take chances. The only safe way is to employ picking gears making one tooth to each pick of the loom, and then to change the gears when different picking becomes necessary.

In many of the existing looms there has been no adequate provision made for the weaver to let the web back to the reed mechanically when a joining becomes necessary through the breaking of the filling while weaving, or where a quill may have run off unnoticed. It is almost impossible to make a joining satisfactorily without proper mechanism being provided for this purpose. In some of the slow running looms provision is made for this by the operation of each set of rolls independently (see Fig. 1), by means of the ratchet gear and pawl A and worm motion B. This plan has the one disadvantage of taking up too much space between the individual pieces. Where the fabric woven is say four or five inches wide, and the space will admit, it is all that can be desired, and the individually weighted rollers C associated with the motion are admirably adapted to variable pressure.

For the very narrow elastic fabrics, which require considerable roller pressure to hold the web snug and firm while weaving, and where it is necessary to make very accurate joinings after a break has occurred, a better movement is one in which the web roll is placed on the main take-up shaft in the form of a sleeve. It is carried around by the shaft as it turns while the goods are being woven, but can be released and turned both backwards and forwards by a conveniently placed hand wheel, which operates a series of differential gears. This movement is entirely independent of the movement of the main take-up shaft drive.

Too much importance cannot be attached to properly controlling the tension of the rubber warp. On its uniformity depends not only the quality, but also the cost of the web. The greater the weight of slack rubber woven into the web the more costly it becomes and the poorer the quality. A very accurate sense of touch is required in testing the tension of the rubber threads as they are being delivered into the goods.

The rubber warp requires the highest possible tension before breaking or chafing of the thread takes place. Each rubber thread should be under this high tension so that when the goods come through the press roll the desired contraction will take place uniformly, and a flat piece of web will be produced that will have plenty of life.

It must always be remembered that the individual threads of rubber which constitute a rubber warp will act as a series of small springs, working in unison with each other. Each one should have equal power to contract the fabric at its own particular part. If any one of these strands or springs is chafed and weakened, it lessens the contracting power, and the result is that the weakened or less contracted part is of relatively greater length than the parts where the rubber threads have retained their full power.

Moreover, the appearance of the goods will be spoiled by the chafed particles of rubber pricking through the face, particularly on the white and lighter colored goods. Before such webs can be marketed they must besubjected to a buffing operation to remove these dirty particles, which is accomplished by passing them over a highly speeded, cloth covered roller, which will remove the loose particles by friction and high velocity. But this operation adds to the cost.

A high and uniform tension of the rubber warp is so important that most manufacturers keep men specially employed in the testing of the threads, instead of leaving this matter to the weavers. These testers acquire such a keen sense of touch that they can obtain very economical and satisfactory results. Talc or soapstone is freely used as a lubricant to reduce the risk of chafing and breaking of the rubber threads. The warps are arranged so as to allow the threads to pass through a bed of plush, loaded with talc, which adheres to the rubber threads and makes them work very smoothly. This is especially important in damp weather, which is the worst condition for the weaving of elastic goods. At times factories have stopped operations when the weather was especially humid.

Fig. 1.—Individual Take-Up Motion for Wide Space LoomsFig. 2.—Individual Rubber Warp Let-Off Motion

Fig. 1.—Individual Take-Up Motion for Wide Space Looms

Fig. 2.—Individual Rubber Warp Let-Off Motion

When we remember that the front reed will pass by the rubber threads possibly six or seven hundred times from their entrance into the shed to their reaching the leaving line, it is not to be wondered at that chafing is liable to take place. With all this liability of spoiling goods it becomesreadily apparent that any device employed to regulate such an important feature as the tension of the rubber warps must be very sensitive and dependable.

On looms making wide goods, and where space will allow, regulation is accomplished by a worm and gear movement as shown in Fig. 2. The iron rubber beam is threaded on to a square shaft A, at one end of which a gear wheel B is fastened. In this gear is meshed the worm C, which is operated by a heavy linen cord D passed twice around a pulley E. The cord derives its movement from a rocking shaft F, on which there is fastened a screw extension G, by which adjustment can be made so as to deliver very accurately any amount from the rubber beam.

With this kind of movement, and in order to feed the thread uniformly into the web, it becomes necessary to use mechanically made warps where the same uniformity has been maintained in putting the warps on the beams. The warps so made must come from the thread manufacturer in individual warps, which are done up in chain form, each warp containing the requisite number of threads.

The machine used for making the warps, shown at Fig. 3, is mounted on an iron frame A, which carries the power driven warp beam B. Behind this is an open top expansion reed C, the dents of which are regulated to open, coarse or fine by an internal spring which is regulated by a hand wheel. This reed also has a screw sidewise adjustment for centering. Behind the reed C are fixed two pairs of nip rolls, D and E, and an open roller F, which is followed by a belt-driven beater roll G, used to beat the threads out straight as they leave the chain.

The rubber warp is first laid on a cloth on the floor, under the beater roll. The end is then passed over the beater roll G, over the open roll F, through the two pairs of nip rolls D and E, over the expansion reed C, and then looped to a leader on the rubber beam, where the knot is put in a counter-sink on the beam barrel, so as not to interfere with the lay of the warp. The section of the warp between the two pairs of nip rolls is brought down in loop form, shown at H, and the nip rolls are then closed while the warp is in this position. The two sets of nip rolls are speeded alike and the rubber is always kept slack between the gripping points, so that all threads passing through the last set of nip rolls, D, are perfectly gauged in length and tension when passing through the reed C and on to the beam B. The threads of rubber are under considerable tension, inasmuch as the beam B is driven faster than the nip rolls D and E.

Where there is limited loom space, and where a small number of threads are employed, as in the narrower garter fabrics, it is not as practical to have the warps made mechanically, and for this reason they are not likely to be put on the beams with as much uniformity of tension. In such cases it becomes necessary to have some automatic device that will correct any irregularities and maintain a uniform delivery throughout. The device for doing this is shown at Fig. 4.

The warp carrier A is fastened to the back rail, which carries the warp, over which is passed the friction cloth G which is hung from a rod D. The friction cloth is fastened at the bottom to the graduated warp lever E, which is bolted to the bottom rail H, as shown. The rubber threads constituting the warp pass in a direct line to the harness C, and then to the breast beam B. The lever E, and the weights F, allow for proper adjustment of the friction cloth so as to keep the lever level as the warp beam empties.

Fig. 3.—Rubber Warping Machine

In making the rubber warps for narrow fabrics such as garters andsuspenders, where the last described method of warp delivery takes place, it is customary to work from an entire sheet of rubber, splitting it up into the required sections or strips of the various sizes called for in the warps. This splitting and warping process must be done in a long room where the warp can be stretched out to its full length, if possible, after it is unchained. These warps are usually about 60 yards long. The “head”of the sheet, or the part where the cutting knife has not gone through, is spread out flat on a series of hooks at the beaming machine and the tail end is fixed securely on a strong hook at the other end of the room.

The requisite number of threads for the several warps which are to be beamed are counted off and each different section is fastened to a beam. The end knot is laid snugly in the counter-sink made in the beam barrel for this purpose. A wide reed is used, covering the number of beams operated in the machine, which is usually about four, and the threads are reeded over spaces opposite the different beams. This reed can be moved sidewise across the face of the beams and each warp properly centered so as to keep the warp level. The operator then starts the beaming machine, which may be operated either by hand or power, and the warps are wound up. At the same time a helper walks towards the beamer carrying the tail end of the warps and keeping the tension as nearly uniform as possible. When the warps are all wound on the several beams, a lease is taken in each of them in the ordinary manner, and each separate section is securely fastened.

Fig. 4.—Automatic Friction Let-Off for Rubber Warps

Should floor space be limited, a horizontal reel is used, which is about six feet long and about five feet in diameter. On this the sheet of rubber is wound after being split in proper sections at the head end and divided by a coarse reed, so as to be able to distribute the different sections all across the reel. Each section can then be taken off the reel as required for the beams. The tension of the threads is governed by a weighted leather strap passed over the face of the reel.

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