GB570399A - An improved method and apparatus for the straightening of the wefts of woven textile fabrics - Google Patents

Abstract

570,399. Straightening weft; webguiding devices. TOOTAL BROADHURST LEE CO., Ltd., and NIELD, L. C. April 27, 1943. No. 6613. [Class 100 (i)] [Also in Group VIII] The weft threads of a textile fabric or woven web of cloth are straightened, if they are not at right-angles to the warp threads, by means which engage the selvedge of the running fabric obliquely and cause lateral deflection of such wefts, this deflection then causing the operation of a weft-straightening device. As shown the fabric 1, Fig. 1, is guided by a device 2 to a horizontal roller 3 from which it passes to the weft-straightening heads 4 and under a roller 17, carried by a counterweighted pivoted lever, to the roller 20 from which it passes to the necessary processing apparatus. Each head 4 consists of a pair of nip rollers 16 disposed at a selvedge with the axes of one pair lying at an angle to the axes of the other pair and each pair is driven from a shaft 5 through a differential gear-box 6 carrying a sprocket 11 which drives a sprocket 12 on a shaft 13 geared by mitre wheels 14 to the shaft 15 of the driven roller of the pair. A finger 21 is disposed adjacent each selvedge and is connected to one of a pair of contacts and, so long as the wefts are at rightangles to the warps, the pull of the nip rollers is balanced and the selvedge do not touch the fingers. Should the wefts, however, lie along lines other than at right-angles to the warps the pull on the rollers becomes unbalanced and the pair of rollers engaging the leading ends of the wefts pull the fabric outwards to engage the corresponding finger and close the contacts. A solenoid is then energized to slide a clutch disc, on a shaft driven from the shaft 5 into contact with the face of a sprocket which is thus rotated and drives a worm 35 engaging a wormwheel in the differential gear-box 6 to cause the speed of the appropriate nip rollers to be reduced thus retarding the edge of the fabric having the leading ends of the wefts and straightening the latter. Alternatively, the rollers at the other edge of the fabric may be speeded up or the one pair may be retarded and the other pair speeded up. The clutch disc may be actuated by air or other fluid means operating a diaphragm or piston or a magnetic clutch may be used and relays or servo mechanism may be employed ; the differential gear-box may be dispensed with and the speed change of the nip rollers given by a second chain-drive with a different gear ratio from that of the sprockets 11, 12 with a sensitive double clutch operated by servo mechanism from the fingers 21, and the fingers may be replaced by a photo-electric cell arrangement. The guiding device 2 and the heads 4 with their driving mechanism are slidable on bars to suit the width of the fabric. In another arrangement the nip rollers are replaced by short chains with pins or other means for engaging the fabric, the chains being pivoted at one end and actuated to move outwards to actuate the fingers. The movement of the lever carrying the roller 17 may be used to synchronize the weft-straightening apparatus with a following or preceding apparatus.