GB316665A - Improvements in and relating to sewing machines - Google Patents

Abstract

316,665. Union Special Machine Co., (Assignees of Christensen, U. V., Rubel, C. F., and Zeier, F. F.). Aug. 2, 1928, [Convention date]. Chain-stitching and double-loop stitching. - A sewing-machine with oscillating loopers has a continuously rotating thread controller with thread guides and controlling elements corresponding in number to the number of looper threads. The invention is illustrated as applied to a machine with three under threads l, l<1>, l<2>, each passing through a tensioning device 4 into a hole 6, 6<1>, 6<2> in a plate 5 and thence to the controller. The controller comprises a hub 9 fixed to the main shaft 3 between discs 7, 8. Each thread engages its own particular part of the controller and passes through notches in a plate 34 to a guide 39 and thence to the three loopers 42 at the end of the arm 40, Fig. 18. The construction of the controller 9 enables each thread to be controlled simultaneously with the difference of degree necessary for compensating for the distance of the looper from the point of emergence of the threads from the arm 40. When the loopers 42 are in their most forward position, the threads lie across the controller in the notches 20, Fig. 13. As the loopers retreat, the controller turns to bring the faces 12, 12<1>, 12<2> into contact with the threads, Fig. 15, to tension the threads. When the loopers are well into the thread triangle, inclined faces 25 on tongues 24, 24<1>, 24<2> on the plate 21 crowd the threads into the recesses 13, releasing the tension and providing enough slack for the loopers to complete the retreating stroke. At this point, the threads lie along the flat side of the controller, Fig. 19, and as the loopers advance again the threads are kept taut by being engaged by the stepped faces 18, 18<1>, 18<2> of the part 19. These steps are necessary owing to the difference of the distance of the loopers from the thread-guiding passage 43 to the arm 40, Fig. 18.