GB549563A - Buttonhole sewing machine - Google Patents

Abstract

549,563. Sewing-machines. FAIRWEATHER, W. C. (Singer Manufacturing Co.). Sept. 6, 1941. No. 11420. [Class 112] In a button-hole sewing-machine such as that described in Specification 549,425 a moving cutter 191 co-operates with a fixed cutter 189 to cut the needle thread above the work and with a cover plate 200 to grip the supply end of the cut thread. The devices are carried on a sleeve 203 mounted in the end of a lever 204 with a fixed pivot 205. The sleeve 203 also carries a plate lever 210 having a cam-slot 211 in which rides a fixed pin 212. Accordingly, the cutters are tilted as the lever 204 moves and the operating point traverses an upwardly convex curved path. The cutter 191 is coupled at 196 to a slide 194 urged by a spring to closed-cutter position. The slide is moved to open the cutters by a lever 214 on a shaft 213 within the sleeve 203 and an arm 216 on the shaft carries a latch 221 of which the tail 217 on the upward movement passes a fixed projection 218 but on the downward movement is used to force the lever 216 anti-clockwise and through the lever 214 depress the slide 194 and momentarily open the cutters. The lever 204 is operated by a cam on the pattern shaft at the close of the stitching operation and before the movement to the initial or button-hole cutting position. The return movement of the lever 204 brings the lever 214 into contact with a stop 223 and a slight further upward movement produced by the actuating cam before the initial stitch of a new button-hole causes release of the thread. The needle thread tension is taken off by the pattern cam at the completion of one button-hole and a thread pull-off is actuated by the clamp-closing lever before the release of the thread end at the commencement of another.