GB818125A - Improvements in zig-zag sewing machines - Google Patents

Abstract

818,125. Sewing machines. PFAFF A. G., G. M. Oct. 1, 1957 [Oct. 9, 1956], No. 30634/57. Class 112 [Also in Group XXIV] Needles, shifting laterally; feed, regulating. In a zig-zag sewing machine an assembly of cam discs for controlling the needle displacement and another assembly of cam discs for controlling the stitch length are mounted on a common rotary shaft. The latter assembly being displaceable axially for selective co-operation with a cam follower and being also displaceable angularly to set up a predetermined phase relationship between said assemblies. A vertical rotary cam shaft 29, journalled in a bearing sleeve 31, has secured thereto by a screw 32 a tubular member 33 which supports a sleeve 35 to which is secured an assembly of cam discs 36 for controlling the needle displacement. Said discs are coupled to the member 33 by means of a pin 34 projecting upwardly from the latter. A sleeve 39, journalled on the upper end of sleeve 35, is biased downwardly by a spring 43 and is formed with a manipulating knob 40 by means of which sleeve 39, and a pair of stitch-length controlling cams 27, 28 secured thereto, may be shifted axially and angularly. Cams 27, 28 are formed with three equally spaced holes 48 and three holes 48<SP>1</SP> displaced 30 degrees therefrom. The lower disc 28 is formed with three equally spaced holes 49 and three holes 49<SP>1</SP> displaced 30 degrees therefrom. The arrangement is such that sleeve 39 may be raised and turned in order to engage holes 48, 48<SP>1</SP> selectively with three pins 47 which project upwardly from the topmost of the cams 36, when cam 27 cooperates with a follower 26 pivoted at 24, or to engage holes 49, 49<SP>1</SP> selectively with the pins 47, when cam 28 co-operates with the follower 26.