GB285710A - Improvements in or relating to buttonhole sewing machines - Google Patents

Abstract

285,710. Bauer, C., (Reece Button Hole Machine Co.). June 20, 1927. Buttonhole sewing-machines. - In machines in which a longitudinal bar is formed at the end of the buttonhole, the cam producing the relative lateral movements between the stitchforming mechanism and the work necessary to form the bar is independent of and separate from the main cam by which the longitudinal movements are produced. The barring cam may be adjusted, and may vary the extent of the bar automatically in accordance with the length of the button-hole. The application to a machine having a stationary work clamp 12, and a movable frame 16 carrying the stitch-forming mechanism is described. The frame 16 is moved longitudinally of the button-hole by a groove in a main cam 19 engaging a fixed pin 21, and the stitch-forming mechanism is rotated in known manner at each end of the button-hole by a shaft 113 which is rocked by a lever 56 pivoted at 110 and having a pin 119 engaging a groove 118, Fig. 5, in the underside of the cam 19. The device for imparting the lateral movements necessary to form the bar comprises a stationary plate 37 having cam slots 41, 42 adapted to be entered by one or other of two spring-pulled bolts 47, 48, depending upon which side of the button-hole is being stitched. The bolts are mounted in a bracket 45 on the under part of the movable frame 16. The bolts are rendered inoperative when stitching around the eye of the button-hole, during which part of the operation lateral movements are imparted by a cam groove 54 acting upon a lever 55 pivoted at 120. To effect this, the ends of the bolts are engaged by double-armed levers 79, 80, the arms 60, 63 of which are connected by links 59, 62 to the opposite ends of an ear 57 secured to the lever 56 which serves to rotate the switch-forming, mechanism. The bolt 48 which is in engagement with the cam slot 42 when the eye is reached, is withdrawn by an arm 64 engaging a fixed stop 65, and the swinging of the links 59, 62, positions the bolt 47 for engagement with the cam slot 41. The cam plate 37 is adjustably secured to the stationary cam 36 by which the starting and stopping gear 24 is operated. The adjustment enables bars of different length to be formed, and the cam 37 may be set so that no bar will be produced. The starting cam 36 is adjustable to vary the length of the button-hole.