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Topic: Vertical Shrinkless Expander With Clamping Fixture

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Vertical Shrinkless Expander With Clamping Fixture

Forced tube expander is the key to process high quality air conditioner heat exchanger The equipment adopts multi axis numerical control technology to realize position conversion, workpiece height adjustment and expansion Get more news about Shrinkless Expanding Machine,you can vist our website!

It has the advantages of high degree of automation, convenient operation and good performance

Depending on the characteristics of characteristic:

1.Forced clamping at both ends of the workpiece, and then expanding the tube, the length of the workpiece will not change and there will be no shrinkage deformation, which can save 3 ~ 5% of the raw materials.

2.The rotation table is used to transpose the position, which realizes the simultaneous completion of two-stage expansion and tube expansion on one machine.

3.The tube expansion height, expansion depth and rotary table positioning are all controlled by servo motor.
United States Harry C. Donaldson, Jr., Troy, and Thomas A. Bramtitt, Watervliet, N. Y., assignors Vto Cine, Peabody da Co., Inc., Troy, N. Y., a corporation of New York Application April 27, 1955, Serial No. 504,221
3 Claims. (Cl. i12- 262) This 4invention concerns a method of manufacturing a seam which obviates or at least alleviates the problem of seam shrinkage. When two or 'more fabrics which are perfectly stable, that is which show no tendency to shrink, are sewn together, and then laundered, they heretofore would inevitably shrink and shorten along the seam. Seam shrinkage is the pucker or contraction which occurs upon laundering at seams, especially at those seams in which several plies of fabric are joined. lt is a wellknown and much studied problem in the textile industry. The pucker is unsightly and unattractive and seriously detracts from the appearance of a garment, but more than that and perhaps more important, it represents a dimensional change which causes fitted garments to become too tight or too short.
It is self-evident that in a seam Athe several plies are squeezed tightly together and will, when conditions permit, 'tend to resume their normal plump equilibrium condition. 'Ihe swelling effects of water on cellulosic fabrics permit this readjustment, and the swelling plasticizing and lubricating eifects of water and heat promote similar release for the more hydrophobic fabrics. T he small quantity of fabric yarns encircled by the threads of a single stitch when swelled by water become thicker and the vertical (normal to the seam) diameter of the stitch must become greater, which it can only do at the expense of the horizontal diameter, Vthat is, the length of the stitch. Obviously as each stitch becomes shorter, the seam becomes shorter. The theoretical cure is also obvious, excess thread in each stitch is necessary. if there is excess thread, the stitch and the seam can become thicker without becoming shorter. A loo-se seam would, therefore, be an answer rbut it is impossible to form a loose seam in machine sewing. There are some indirect approaches to the loose seam, such as sewing a piece of cardboard or heavy paper into the seam and then tearing it out. That method adequately prevents seam shrinkage, but is not efficient for high speed mass production efforts. In addition,l a loose seam is less attractive and less reliable than a tight seam. v
A better answer is to sew a tight `seam with a thread which Will become longer when laundered. 011e such thread suggested is a composite of a water soluble yarn and the normal sewing thread twisted together. When the water soluble component is removed as by laundering, there is excess thread in the seam by reason of the now unnecessary spirality. This is a reasonable answer to the problem, but the water soluble component must have af yield point and stress strain behavior approximately that of the permanent component or the spirality and eiectiveness of the composite will change under the tension of sewing. This property of high yield point vand high strength, equivalent to a typical sewing thread, is
dilicult to realize in a water soluble yarn, which yarns are for the most part Very elastic. In addition, the aforementioned equivalency of stress `strain behavior, when realized, `is almost inevitably lost by the plasticizing iniluence of Water vapor at high humidities upon the water ICC soluble component.` The bulky composite thread is difficult to pull through the fabric and causes excessive needle heat. The composite thread therefore, although it offers a theoretical cure for seam shrinkage is not commercially attractive.
We have discovered a means of producing a seam which does not shrink appreciably and which avoids the diculties attendant upon the Iuse of the composite thread mentioned above.

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