GB831181A - Needle clamps for sewing machines - Google Patents

Abstract

831,181. Sewing machines. SINGER MANUFACTURING CO. July 17, 1958 [July 17, 1957], No. 22956/58. Class 112 In a sewing machine having a curved needle secured by clamp means to a rock arm with the needle point in a predetermined position relatively to the latter, the clamp means has associated therewith means for selectively varying the angular arrangement of the needle with respect to the rock arm about said predetermined point. In a blind-stitching machine a curved needle 17 is held between clampmembers 19, 20 by a clamp screw 21. A curved projection 22 from member 20 is slidable in a groove 28 in a rock arm 25 fast with a rock shaft 24. A clamp screw 29 passes through a curved slot 23 in projection 22 to hold the latter in adjusted position in groove 28. The arrangement is such that the point of the needle is positioned at the centre of the radius of curvature R of slot 23, and always enters the fabric ridge formed over the oscillatory work binder 12 at the same point. Normally, extension 22 is so adjusted that the axis of the needle is coincident with the path of movement of the needle point. For hard finished fabrics which tend to deflect the point upwardly, extension 22 adjusted inwardly of groove 28 to position the needle axis along a line such as BB, For soft fabrics or for fabrics having high naps and which tend to deflect the point downwardly, extension 22 is withdrawn from groove 28 to position the needle axis along a line such as CC.