GB782003A - An apparatus for stretching fabrics - Google Patents

Abstract

782,003. Finishing fabrics. AETNA-STANDARD ENGINEERING CO. July 25, 1955 [Aug. 16, 1954], No. 21434/55. Class 42 (1). [Also in Groups XI, XXXV and XXXVIII] An apparatus for stretching fabric, e.g. of nylon or polyester resin, while it is travelling through an oven in web form comprises means for drawing the fabric into and out of the oven and stretching the fabric drastically during its passage therethrough, and means between the ends of the oven whereby the fabric is exposed to heat over a distance which is varied automatically in conformity with the current rate of travel of the fabric. Stretching. Fabric is fed by rollers 15-18 to an oven comprising a heating leg 2, a cooling leg 3 and a top structure 4. The fabric is withdrawn from the oven by rollers 31-34 and passed over a dancer roller 39 to a calender or other take-up unit. The movement of roller 39 is used to control the relative speeds of the whole heating and stretching apparatus and the take-up unit. In structure 4, the fabric passes over a roller 43 which is sensitive to fabric tension; movement of roller 43 operates a tension-indicating scale and can also be used to control the speed of rollers 31-34 so as to automatically control the fabric tension. Tachometer rollers 29 and 35, associated respectively with the feed and delivery rollers, drive tachometer generators; the output of these generators may be used to indicate stretch and, as an alternative to the tension control arrangement, to control the degree of stretch by controlling the speed of fabric delivery. Heating. The sides of heating leg 2 are lined with electric heating elements which are screened from the fabric F by adjustable curtains to a degree dependent on the speed of the fabric as measured by tachometer roller 35, and a thermo-pile unit, sensitive to the temperature of the fabric, controls the voltage supplied to the heating elements so as to maintain the fabric temperature opposite unit 54 substantially constant (see Group XI). The air in leg 2 is drawn by a fan out at one side into a duct 114 and fed back at the other side through a duct 122, an air exit 120 being controlled either manually or automatically so as to bleed out sufficient hot air to maintain the air in leg 2 at a desired temperature. Cooling. Cooling air is drawn by a further fan 106 through the open bottom 102 of leg 3, up leg 3 and through top structure 4, and is discharged through an exit 110. If the travel of fabric F stops, vanes 111 move to close exit 110 and a damper opens to allow the cooling air to travel down leg 2 to purge that leg of hot air; simultaneously, the shutters or curtains move to completely screen the heating elements.