GB818970A - Sewing machines and methods - Google Patents

Abstract

818,970. Sewing machines. CLUETT, PEABODY & CO. Inc. Feb. 15, 1957, No. 5295/57. Class 112 In a lock stitch seam a predetermined amount of slackness is produced in the looptaker thread, to counteract the formation of seam shrinkage and stitch pucker in subsequent laundering of the fabric, by alternately holding the looptaker thread on opposite sides of the path of the stitching needle and of the seam during the formation of each successive stitch. Said holding is effected by moving a finger 35 back and forth across the path of the needle 6 into and out of engagement with the looptaker thread 39, said finger projecting in the direction of seam formation. The needle thread 38 is tightened along the upper surface of the fabric in the usual manner. Finger 35 is carried by the upper end of an arm 32 arranged to reciprocate transversely of the direction of work feed in a slot 33 formed in the throat plate 11 in front of the needle. Arm 32 is fixed to one end of a rod 28 slidable in a bracket 29, a pin 30 on the other end of rod 28 being disposed in a slot 27 formed at the lower end of a lever 23 pivoted at 24. A cam follower pin 26 on the upper end of lever 23 co-operates with a cam groove 22 formed in a cam drum 21 carried by a shaft 20 driven by gearing 17, 18, 19 from the main shaft 8 of the machine. The finger 35 is moved across the needle path each time the needle commences its descent, and consequently remains in contact with the loop-taker thread until the subsequently formed stitch has been set. The action of the feed dog then serves to move the stitch off the finger. The degree of slackness is determined by the stroke of rod 28, and said stroke may be varied by changing the cam drum 21. In a modification, Fig. 7, the finger is in the form of a length of wire 42 over which a plurality of stitches is formed.