GB937680A - Improvements in or relating to attachments for sewing machines - Google Patents

Abstract

937,680. Sewing-machines. NECCHI S.p.A. June 12, 1961 [July 22, 1960], No. 21114/61. Class 112. A buttonhole-foot for a sewing-machine comprises a support carrying a soleplate and a blade pivotally carried by the support for movement to a fabric penetrating position for cutting the fabric, within the sewn outline of a buttonhole, in response to movement of the fabric in the general direction of the buttonhole. A support 1 (see Fig. 4), secured to the presser bar has pivoted to it at 4 a sole plate 5. Pivoted to the support at 6 is a support 8 provided with a cutting blade 9, the support 8 being spring-biased into a raised position where the blade lies within the general confines of the support 1 and does not constitute a hazard to the operator. A handle 16 on one side of the support 8 allows the support and blade to be rotated down, the blade 9 penetrating the fabric inside a completed buttonhole and entering the needle slot 19 in the stitch plate 20. As the fabric is moved in the direction X pressure of the fabric maintains the knife in the lowered position. To control the length of the cut formed by the blade the foot is provided with a slider 22 having grooves 23, 24 (see Fig. 2), slidably engaged with the edges of the sole plate 5. The underside of the slider 22 has teeth 25 engaging the fabric 17, the slider moving with the work as the buttonhole is sewn. Fixed stops 27 and an adjustable stop 28 disposed at opposite ends of the slider engage ends 32 and 32 respectively, of the sole plate to limit the movement of the slider relative to the plate. After the buttonhole has been stitched the feed dog (not shown) is lowered, the blade 9 moved to penetrate the work and the slider moved, together with the work, to cut the buttonhole. At the end of the cut an inclined surface 41 on a second adjustable block 40 engages an appendage 42 (Fig. 2), to raise the blade before the bar tack is cut. To return the slider to its starting position when the foot is raised to move the fabric before commencing a new buttonhole, the slider has a spring- biased pulley 46 around which is wound a cable 48 having one end connected to the support 1. To permit the buttonhole to be sewn automatically, a lever may be pivoted to the support in such a manner that its lower end is engageable with inclined surfaces 57, 58 on the slider, the upper end engaging parts of the sewing machine described in Specification 902,346 to cause the automatic production of the buttonhole.