GB541130A - Stretching work-clamp for sewing machines - Google Patents

Abstract

541,130. Sewing-machines. FAIRWEATHER, W. C. (Singer Manufacturing Co.). Aug. 1, 1940, No. 12436. [Class 112] Button hole sewing-machines. With an undivided work-clamp, the work is stretched after the clamping pressure is fully applied. In one form a groove 68, Fig. 3, is cut in the work plate 30, on to which the clamp closes, and when the clamp is closed a plate 65 slidably mounted on pins 66, Fig. 7, on one inner wall of the clamp, is pressed into the groove 68. In another form, one of the walls 108, Fig. 17, of the clamp is pivotally mounted on the clamp structure and is turned slightly after the clamp is closed to move its work-engaging surface away from that of the other wall 107. In the former case, the depression of the plate 65 is caused by a cam 72 on a shaft 73 which may be operated by a finger piece 75 or automatically. In the latter case, the cam 72 in co-operation with a spring 113 acts only as a holding device and the wall 108 is tipped by means of ball-ended screws 111 which engage a lever arm 110 secured to the wall 108. The stretching device is depressed automatically, after the clamp is closed by means of a lever 77 connected to the stitch starting gear which engages a ball-ended projection 76 on the shaft 73 and is raised after the stitching operation by means of a link 86 connected with the clamp-opening gear. The machine may be used to stitch a line or bar of stitches at the end of a garment waistband and the cutter, normally used for cutting the buttonhole, trims off the projecting end of the waistband. The cutter is given a needle-avoiding movement as described in Specification 542,617.