GB321951A - Improvements in folding chairs - Google Patents

Abstract

321,951. Fairweather, WÀ, (Singer Manufacturing Co.). Feb. 12, 1929. Buttonhole sewing-machines; thread cutters and thread-end holders. -Provision is made in a buttonhole sewing-machine to separate the work and threads at the completion of each hole, to permit easy and harmless operation of the thread-cutter. The invention is described as applied to a machine with stitch - forming mechanism, as described in Specification 179,278. buttonhole cutting and work-clamping mechanism as described in Specification 183,873, and thread-cutting mechanism as described in Specifications 223,124 and 223,801. Access to to the threads by the cutting mechanism 41, 45 is obtained by periodically lifting the frontend of the work-support 24 by a cam 72, Fig. 8, when the work-clamps 25 are holding the finished buttonhole just after it has been cut by the cutters 16, 17. The thread-cutter consists of a pair of scissors 41, 45. The blade 41 is carried by a lever 42 pivoted at 43 to the frame. The blade 45 is pivoted to the other blade at 44 and its tail has a later projection 46 entering a cam-slot 47 in the plate 48 for closing them. The lever 42 is operated by the link 49, lever 50, and gearing connected to the main shaft as described in Specification 223,801. The means for lifting the work-clamp is carried by the thread-cutter lever 42. Two pins 71 secured thereto carry a cam 72 with a circular portion 73 and a cam portion 74. These portions engage a roller 61 carried by a plate 60 which has a pair of sleeves 69 in which are pins 58. The pins have notches 62 engaged by a plate 63 normally urged to locking position by a spring 67, Fig. 3. When the work-clamp is shifted to buttonhole cutting position, Fig. 8, the roller 61 lies directly over the plate 72, so that as the lever 42 is operated to advance the thread-cutter 41, 45, the pins 58 are lifted, so tilting the work-clamp and giving free access to the under thread, needle-loop threads, and stay-cord c, to permit cutting without danger of damaging the under-surface of the material, whatever its texture. The point 41' of the upper blade is preferably offset towards the work-plate. The cutter mechanism carries a thread-nipper of the kind described in Specification 223,124.