GB769389A - Zigzag sewing machines - Google Patents

Abstract

769,389. Sewing machines. SINGER MANUFACTURING CO. May 23, 1955 [May 27, 1954], No. 14757/55. Class 112. In a zig-zag sewing-machine with an exchangeable pattern cam and a cam-follower lever with means for holding the latter in a desired position when the cam is removed as described in Specification 772,570, the shaft of the cam-follower lever is linked to the upper end of an arm 58 on a hollow shaft 60 and the needle-vibrating pitman 27 is connected to a cylindrical slide 66 in a corresponding guideway formed in a member 93 which is pivoted to the upper end of the arm 58 and is oscillated with the arm about the shaft 60 by the action of the cam, the amplitude of the vibration of the needle-bar being adjusted by shifting the slide 66 along the guideway by means of a link 73 from a handoperated lever. The member 93 is constrained to move with the arm 58 by a pin 80 carried eccentrically on a spindle 78 in the bore of the shaft 60, and is adjusted about its pivot on the arm 58, to adjust the "zero" position of the needle laterally, by turning the spindle 78 by means of a finger-knob on its other end; a collar 85 fixed on the shaft 60 has abutments 87 to determine the extreme positions of the member 93 by engagement with a spring plunger 83 in the latter and a central groove to be engaged by the plunger in the normal position of the member 93. In the form shown, in order to avoid lateral shift of the needle-bar by adjustment of the slide 66 along the guide, the slide engages a slot 96 in the end member 94 of the needle-vibrating pitman 27 and the oscillation of the member 93 is imparted to the pitman by a pin 98 on the latter engaging a curved groove 97 in the former, this groove being centred on the point of connection between the pitman and the needle-bar frame when the member 93 is in mid-position.