GB1343832A - Sewing machines - Google Patents

Abstract

1343832 Upper feed mechanism UNION SPECIAL MACHINE CO 19 April 1971 [6 March 1970] 23268/71 Heading D1G In a sewing machine the top feed mechanism comprises a top feed bar 22 mounted below the sewing machine's throat plate 64, a top feed dog 50 pivoted to the feed bar 22 and means 17, imparting lift and feed motions to that bar. As shown the top and under feed dog bars 22, 23 are disposed alongside each other and receive lift and feed motions from the same shaft (11, Fig. 2 not shown) which is provided with an eccentric portion 17 providing lift and a further eccentric portion (16) producing a feed stroke. The portion 17 is provided with a fixed eccentric 19 embraced by the forked end of the upper feed bar 22 and a free block 20 embraced by a forked end of the lower feed bar 23. The eccentricities of parts 17 and 19 are 180‹ out of phase so that the feed dogs 50, 43 move together towards and together away from the work to clamp the work therebetween during feeding. Feed motion is imparted to the bars by respective links 39, 36 embracing an eccentric 32 keyed to portion 16. Link 36 is apertured at 41 to permit link 39 to engage the inner bar 22 therethrough. The upper feed foot or dog 50 is secured to a carrier lever 48 pivoted at 47 to a carrier mounting bracket 45 secured to feed bar 22. Lever 48 is urged clockwise as seen in Fig. 1 by a spring 58 abutting a stop 57 secured to a rod 53 slidably received in a guide 55 secured to that feed bar. When the presser foot 67 is raised by actuation of lever 65 a pivoted plate 60, connected to lever 65 by rod 70, turn to cause its camming surface 63 to abut the end of rod 53 and urge it against the action of bias spring 58 and to raise the upper feed dog from the material.