GB867725A - Improvements relating to stitch adjusting devices for sewing machines - Google Patents

Abstract

867,725. Sewing machines. ANKERPHOENIX NAHMASCHINEN A. G. Nov. 21, 1958 [Nov. 22, 1957], No. 37568/58. Addition to 781,156. Class 112 The arrangement claimed in the parent Specification is modified in that the vertical connecting rod, driven by an eccentric on the rotary hook drive shaft, is coupled by a pivot pin to two swinging links situated on one side of the pivot pin, one link transmitting drive to the feed shaft and the other link being associated with stitch length-adjusting means, the arrangement being such that the links, in the zero feed position of the adjusting means, describe about their ends remote from said pivot pin arms which substantially coincide with one another in the region of movement of the pivot pin. A vertical connecting rod 45, driven at its lower end by an eccentric on the rotary hook driving shaft 47, is pivoted at its upper end both to a swinging link 46 and also to a comnosite swinging link constituted by two separate links 42 and 43. Link 46 is pivoted to an arm 54 rigid with the feed advance shaft 50, which is coupled by arms 51 and a pivot pin 52 to the feed bar 53. Links 42, 43 are pivoted to a frame 33, and aligned shafts 30, 34 rigid with the latter are journalled in bearings 32. An arm 31 rigid with shaft 30 is coupled by a linkage 25, 26, 28 to a rotary stitch length-adjusting knob 23. A spring 35 acts on shaft 30 to bias the linkage to zero feed position, when arms 42, 43 are horizontal. When the latter are moved, by the manipulation of knob, 23, above or below the horizontal, feed movement is transmitted to the feed bar in opposite directions respectively.