Sewing of book blocks without blind stitch

Abstract

A solution is proposed for sewing blocks of signatures (115) in a bookbinding sewing machine (100). A corresponding method comprises, for each block of signatures (115), forming one or more stitchings (220, 225) between the signatures (115) of the block by corresponding sewing threads (215), each stitching (220, 225) comprising one or more plain stitches (220) and one or more looped stitches (225) concatenated to each other and ending with a free loop (240) on a last one (115N) of the signatures (115) of the block, bringing each sewing thread (215), downstream the corresponding plain stitches (220) along a formation direction thereof, to an intermediate position aligned with the corresponding free loop (240) along an advancement direction (235) of the blocks of signatures (115) during the sewing thereof, bringing a closing portion of each sewing thread (215) from the intermediate position through the corresponding free loop (240) along the advancement direction (235), the closing portion consisting of a portion of the sewing thread (215) downstream the corresponding plain stitches (220) along the formation direction thereof, blocking each sewing thread (215) at a gripping point comprised in the closing portion thereof by actuating a corresponding gripping device (250), cutting each sewing thread (215) downstream the gripping point thereof along the formation direction of the plain stitches (220), pulling each sewing thread (215) being cut by moving the corresponding gripping device (250), which blocks the sewing thread (215) being brought through the corresponding free loop (240), away from the corresponding free loop (240) thereby tightening the free loop (240) around the sewing thread (215) being cut, and releasing each sewing thread (215) being pulled by ceasing the actuation of the corresponding gripping device (250).

Dependencies are inferred from the claim text.