GB1071562A - Improvements in sewing machines - Google Patents

Abstract

1,071,562. Sewing machines. UNION SPECIAL MACHINE CO. Jan. 28, 1966 [Feb. 1, 1965], No. 3853/66. Heading D1G. In a multi-needle, feed-off-the-arm sewing machine having main and differential feed bars in side-by-side relation, at least one of the working surfaces of the latter is stepped. As shown, three needles 21 co-operate with three loopers carried by a shaft 23 in the lower arm 16 to unite the inter-folded part of work pieces 86, 87. Shaft 23 is rocked, for effecting looptaking movements, via a pitman 24 from an eccentric 26 on the upper arm shaft 18. Shaft 23 is reciprocated axially, for effecting needleavoiding movements, from a lever 28 oscillated via a pitman 29 from an eccentric 31 on shaft 18. A main feed bar (34), Fig. 2, and differential feed bar 43 slidably engage a block 36 pivoted on a fixed pin 35. A pitman 39, actuated by an eccentric 42 on shaft 18, is connected to a pin (38), Fig. 2, on feed bar (34), and pin (38) is slidably embraced by a portion of feed bar 43, whereby feed lift movements are imparted to the feed bars. An arm 48 of lever 28 is connected by a link 51, having an adjustable pin-and-slot connection therewith to an arm 53 pivoted on a fixed pin 55. An arm rigid with arm 53 is connected by a link to feed bar 34 for imparting feed advance movement thereto. Arm 53 is connected by a link 61, having a pin-and-slot connection therewith, to feed bar 43. One arm 66 of a bell crank lever pivoted on pin 55 is connected by a link 64 to link 61, and the other arm 67 has a pin-and-slot connection with an adjusting lever (71), Fig. 7, for varying the feed stroke of feed bar 43. A main feed dog 32, on bar 34, has stepped teeth, those of the leading section 82 being higher than those of the trailing section. The differential feed dog 45, on bar 43, operates in a raised portion 77 of the throat plate 76. Dog 45 also has stepped teeth, those of the leading section 85 being higher than those of the trailing section, and all the teeth of dog 45 are higher than the teeth of dog 32. The folded part of the work pieces 86, 87 is guided by a composite presser foot 88, 89, and guide bars 90 for said folded part are provided on arm 16.