GB1003189A - Thread cutting equipment for sewing machines - Google Patents

Abstract

1,003,189. Sewing machines. N. CORAH (St. Margret) Ltd. Feb.18, 1964 [March 2,1963], No. 8438/63. Heading D1G. A lock stitch sewing machine comprises a thread cutter pivotally mounted above the stitch plate, a thread cutter pivotally mounted below the stitch plate, a lever and linkage system associated with each cutter, and a single manually-operable lever coupled to said systems for simultaneous actuation of said cutters to sever the upper..and lower threads. An upper cutter blade 13 is pivoted at 14 to the presser foot 19, and has an extension 15 pivoted to the lower end of a lever 16 pivoted on the preser bar 17. A pin 18 on the upper end of lever 16 is disposed in the lower forked end of an arm 19 rigid with one end of a rod 20 horizontally slidable in fixed sleeves 22. An arm 23, rigid with the other end of rod 20, carries a pin 24 disposed in the forked end of an arm 25 rigid with a vertical shaft 26 journalled in the base plate 1 of the machine. A lower cutter blade 28 is pivoted at 31 below the base plate 1, and is rigid with a threadpositioning finger 29 disposed in advance of the cutting edge 30 of blade 28. The latter is connected by a linkage 32, 33, 37 to an arm 38 rigid with shaft 26. A finger piece 40, disposed above the base plate, is rigid with a vertical shaft 41 which is journalled in the latter and is connected by a linkage 42, 43 to arm 38. Actuation of finger piece 40 thereby serves to actuate the blades 13 and 28 simultaneously, the blades being returned by a tension spring 45. The strokes of the blades are determined by the position of collars 44 adjustably fixed on rod 20 between the sleeves 22.