GB1166127A - Improvements in or relating to blindstitch sewing machines - Google Patents

Abstract

1,166,127. Sewing machines. UNION SPECIAL MACHINE CO. 13 June, 1967 [15 June, 1966], No. 27203/67. Heading D1G. Ridge-forming means in a blind stitch sewing machine are driven by a toothed belt extending from a toothed pulley operatively associated with a main drive shaft to a toothed pulley operatively associated with the ridge-forming means. A base 10 has an upwardly-extending front portion 10a and a rear column (11) supporting a laterally-extending arm 12 rigid with a forwardly extending arm 13. A shaft 15, rigid with portion 10a, journals a laterally-extending work-supporting member 14 having an extension 14b located under arm 13. A spring (25) acts on a depending portion 14a of member 14 to bias a stop screw 17, carried by portion 14a, against one end of a rod 18 slidable in base 10 and biased inwardly by a spring 18b. The other end of rod 18 is pivoted to the lower arm of a two-armed lever (19), the upper arm of which abuts a fixed stop (21) to determine the level of the upper surface of member 14. The position of stop (21) may be adjusted, to vary the level of said surface, by turning a knob 23. A stop screw 29 engages portion 10a to limit the inward movement of rod 18. A shaft 30, journalled in arm 12 and driven by a pulley 31, oscillates a shaft 32 journalled in arm 13 and carrying a curved needle 33. Shaft 30 also imparts reciprocating and turning movements both to a rod 34 carrying a looper 35, and also to a rod 36 carrying a feeding foot (37). The work is introduced between a presser plate 43, rigid with arm 13, and a pair of platens 38 vertically slidable in extension 14b and spring biased against plate 43. A ridge-forming bar 45, vertically slidable in extension 14b between the platens 38, is connected by a pivotal link 47 to a crank disc 48 on one end of a shaft 49 journalled in member 14. The other end of shaft 49 carries a toothed pulley 52 coupled by a toothed belt 53 to a toothed pulley 51 on shaft 30 for reciprocating ridge-forming bar 45. Slack in belt 53 is taken up by the engagement with the lower run thereof of a pulley 54 journalled on a pivoted arm 55 and biased against belt 53 by a spring 58. Member 14 may be lowered for the introduction of work by actuation of a knee pad 61 coupled to member 14 via connections 62, 64, 65. Member 14 may alternatively either be fixed or be oscillated intermittently to produce skip stitches. Pulleys 51, 52 and belt 53 may be located either externally of the machine frame, as shown, and protected by a hood (60), or within the frame, Fig. 16, when the driven pulley may be located either on shaft 30 or ,be spaced therefrom and driven from shaft 30 by spur gearing or by a toothed belt. In a modification, shaft 49 is rotated at half speed and reciprocates a pair of side-by-side ridgeformers by crank connections spaced 180 degrees apart, the arrangement being used for zig-zag stitching. In a further modification shaft 49 carries a pair of cam lobes, either aligned or axially spaced, said lobes serving as ridge-farmers, shaft 49 being driven at half speed. The platens are then pivotally mounted.