GB673517A - Improvements in or relating to sewing machine attachment - Google Patents

Abstract

673,517. Sewing-machines. GRETST MANUFACTURING CO. June 5, 1950 [June 9, 1949], No. 13978/50. Class 112. Feed by presser-foot or the like.-An attachment for zig-zag or similar stitching comprises a lever pivoted to a frame and carrying a presser-foot, a cam rotated by the needle-bar and engaging means on the lever to oscillate the latter, and means to vary the rotation of the cam relatively to the reciprocation of the needle-bar. In the device described the cam is driven in the usual way by ratchet gear, and masking means are provided to prevent engagement of the pawl periodically. In the form shown the.presser-foot 48 is pivoted by pins 47 on a lever 28 which is slotted at 29 to engage a pivot pin 27 carried in a slot 26 in a frame 13 clamped to the presser-bar; the pin 27 is movable along the slots, to vary the lateral movement of the presser-foot, by an adjusting slide 33 with finger-piece and clamping means. A pin 30 on the lever 28 projects through a transverse slot in the frame 13 to engage a peripheral undulating cam-track in a cam-wheel 19 secured on a spindle which is rotated by a needle-bar-actuated lever 60 through a pawl 63 and ratchet-wheel 62 to impart a lateral throw to the presser-foot at each step of the camwheel. To provide for forming sequences of stitches involving straight as well as transverse stitches interchangeable masking cams 69 may be clamped on the spindle by a nut 70; the cam 69 is actuated by the same pawl 63, but when the latter engages a shallow notch 72 in the cam 69 it is prevented from engaging the ratchet-wheel 62 and thus makes an idle stroke during which a straight stitch is made, a lateral stitch being produced when the pawl engages a deep notch 73 (every third stitch in the form shown). Presser-foot; cording-guides.-The presserfoot, which has a serrated under side, engages its pivot pins 47 on the lever 28 by means of notches, which are held against the pins by resilient limbs on a plate 53 fixed to the foot. This plate also provides a cording-guide 52 which co-operates with a groove in the presserfoot.