GB292872A - Chain-stitch sewing machines - Google Patents

Abstract

292,872. Fairweather, W., (Singer Manufacturing Co.). Jan. 21, 1928. Multiple-needle machines; chain-stitching.-A chain-stitching machine of a similar kind to that described in Specification 270,174 has a loop holder and a looper for each needle, operating in substantially coincident planes at the same side of the needle path parallel to the line of feed, such loop-holder and looper having simple oscillatorv movements. The invention is illustrated as applied to a three needle machine. At the moment the needles 10 begin their upward stroke, loop holders 13 are timed to advance their points 14 into the needle loops. As the needles continue the upward stroke, the points 14 engage the needle loops and hold them without spreading while the loopers 17 advance into position for entering the loops, Fig. 6. At the limit of the upward stroke of the needle, both loop holder and looper are engaged in the loop. As the needle descends again, the loop-holders retire from the loops and the loopers 17 present the loops for entry by the needle, on its down stroke, Fig. 8. The cycle is repeated as the needle re-ascends. The loopholders 13 are mounted on a shaft 11 and are driven by a crank 23, pitman 21 and eccentric 19 on the main shaft 6. The loopers are mounted on a pin 16 secured by a strap 15 in parallel rotation to a hollow shaft 12, coaxial with the shaft 11 and driven by a crank 24 and pitman 22 from the eccentric 20 on the main shaft. The needle holes 42 have shelves 43 with inclined edges 44 to assist the looper thread to bow away from the blade of the looper and open for the needle. Governing needle-thread. - The needle threads are governed by a rotary take-up and a thread nipper. The take-up comprises spaced parallel discs 7 between which is located a fixed plate 45, Fig. 3, having a thread slot 46. A bent wire guide 47 positions the thread for the action of the discs. The thread-nipper comprises a seat 48, yieldingly mounted in a recess 50 in the arm 4, and a head 49. As the shaft 6 rotates, an eccentric 56 actuates a follower 55 and yoke 54 to reciprocate the rod 53 to release and nip the thread between the parts 48, 49. A multiple threadtensioning device is provided comprising the spring-pressed tension discs 57 mounted on the plate 58 which is held spaced from and fixed relatively to the supporting plate 59 by corner posts 60, the plate 59 being coaxial by a bracket 61 on the gooseneck 4. A movable plate 62 is slidably mounted on the posts 60 and it has a cam disc 63 co-operating with the cam disc 66 so that when the disc 66 is turned, the plate 62 is forced away from the plate 59 against the spring 68 and lifts the tension release pins to separate the tension discs. Feed by dogs.-The dog 25, Fig. 5, receives its up-and-down motion from the shaft 29 by the links 28, 26 and its to and-fro motion by the shaft 34 and links 33, 31. The shafts 29, 34 are driven from the main shalt 6 by eccentrics 39, 40, pitmen 37, 38 and crank 36.