GB324263A - Improvements in or relating to buttonhole apparatus for sewing machines - Google Patents

Abstract

324,263. Dehn, F. B, .(W³rker Ges.). Feb. 18, 1929. Buttonholes, attachments for sewing. - A buttonhole sewing attachment for a domestic sewing machine comprises two hinged parts, one secured to the presser-bar and one to the workplate, and is operated from the needle-bar by a ratchet. The lower plate 1 is secured to the machine by a screw S and covers the usual throat plate 3 and feed dogs 2. It has a pair of lugs 4 forming, with the pin 5, the hinge for the upper plate, 6 which carries the mechanism and is secured to the presser-bar 44 by the box 42 and hinge 45, 46, 47. The plate 6 carries on its underside a plate 7 to which is connected the cloth clamps 8 by pins 9. The clamp derives its zig-zag stitch forming movements from a bell-crank 38 and cam 39 in the box 42. It derives its longitudinal and transverse button-hole feeding movement from a rack 24 operated by the pinion 25. The pinion is rotated by a one-way friction clutch 22, an arm 21 of which is given a forwards and backwards movement by lugs 20, 19 on a rod 17 operated by the lever 12 and ratchet 14 connected to the needle bar 11. The rack 24 communicates the longitudinal motion to the plate 7 by rocking a lever 28 pivoted at 30, by the pin 29; the lever 30 is connected to the plate 7 by a pin 33 engaging slots 31, 34 and the throw of the plate 7 and consequently the length of the buttonhole, is regulated by the position of the pin 33. The zig-zag movements of the plate 7 do not affect the connection between the rack and lever 28 owing to the provision of the slot 27 for the lateral movements of the pin 29. The lateral movement of the plate 7 is derived from the rack 24 by a flange 35 thereon entering and sliding in a slot 36 in the plate. The part of the plate 1 which covers the feed dogs and throat plate. may be hinged or pivoted to the main part.