GB327296A - Improvements in sewing machines - Google Patents

Abstract

327,296. Armstrong, J. J. V., (Union Special Machine Co.). April 13, 1929. Loop stitching.-A machine for stitching edges has a main shaft arranged above the plane of the work support and extending rearwardly of the stitching point in the general direction of the teed, and carrying eccentrics which directly operate the feeding and stitch-forming mechanisms to permit rapid and smooth working. The invention is illustrated as applied to an overedge stitching-machine with a needle 28 and two thread-carrying loopers 43, 46. The needle-bar 29 reciprocates in a sleeve 30 fixed to the lug 31 and has a collar 34 with a pin sliding in a slot and engaged by a link 36 connected to a crank 41 on the disc 42 on the actuating shaft 6. The looper 43 is mounted on a carrier 44 on a shaft 45. The looper 46 is mounted on a carrier 47 clamped to the shaft 48. The loopers are connected by an arm 50 and link 51 so that as the shaft 48 is oscillated, the loopers oscillate so that the needle loop is entered by the loopers. Feed by dogs.-The material is fed across the work support by a main feed-dog 8 and an auxiliary feed-dog 9. The dog 8 is adjustably carried by the bar 10 pivoted at 11 to the feed rocker 12 mounted on a shaft 13. The rocker is rocked by a link 15, adjustable stud 17, link 18 and mainshaft eccentric 19. The ball stud 17 is directly under the main-shaft 6 which is located in a vertical plane cutting a plane containing the line of feed at a small acute angle at the stitching point. The dog 9 is adjustably carried by the lever 20 pivoted on a member 21 carried by the main feed bar 10. The lever 20 has a rod 22 sliding in the sleeve 23 pivoted on an arm 24 adjustably fixed to a lug 25 on the frame. The arm may be held in adjusted position by lock nuts 26. Both feed bars are raised and lowered by the link 27, link 72 and eccentric 73. The sliding of the rod 22 changes the angular position of the auxiliary bar causing the dog 9 to leave the work slightly earlier than the main dog 8 so that the dog 8 has a slightly longer feed stroke to prevent stretching. Trimming or cutting.-The fabric is trimmed prior to stitching by a leger blade 59, adjusted by a screw 63, and a moving blade 60 carried by a head 67 on a rod 68 on a lever 65 fulcrummed on a support 66. The lever 65 is oscillated by the link 72 and eccentric 73, the link being connected to the lever by the ball joint 74. The cutting movements are thus synchronized with the up-and-down movements of the feed-dogs. Presser-bars.-The presser-foot 77 is carried on an arm 78 mounted on the shaft 79 which has an extension 80 over the end 83 of a lift lever 81 pivoted at 82 and operated manually.