Sewing of book blocks without blind stitch

A sewing station for sewing blocks of signatures in a bookbinding sewing machine, wherein the sewing station comprises:

• a series of needles and crochets for forming one or more stitchings between the signatures of each of the blocks by corresponding sewing threads, each stitching comprising one or more plain stitches and one or more looped stitches concatenated to each other and ending with a free loop on a last one of the signatures of the block,
• a series of shuttles each for bringing a corresponding one of the sewing threads, downstream the corresponding plain stitches along a formation direction thereof, obliquely to an advancement direction of the blocks of signatures during the sewing thereof to an intermediate position aligned with the corresponding free loop along the advancement direction,
• a series of gripping devices each for bringing a closing portion of a corresponding one of the sewing threads from the intermediate position through the corresponding free loop along the advancement direction, the closing portion consisting of a portion of the sewing thread downstream the corresponding plain stitches along the formation direction thereof,
• a mechanism for actuating the gripping devices each to block the corresponding sewing thread at a gripping point comprised in the closing portion thereof,
• a series of cutters each for cutting a corresponding one of the sewing threads downstream the gripping point thereof along the formation direction of the plain stitches,
• the mechanism for moving the gripping devices, each blocking the corresponding sewing thread being brought through the corresponding free loop thereby tightening the free loop around the sewing thread being cut, and
• the mechanism for ceasing the actuation of the gripping devices each to release the corresponding sewing thread.

A bookbinding sewing machine comprising a sewing station, wherein the sewing station comprises:

• a series of needles and crochets for forming one or more stitchings between the signatures of each of the blocks by corresponding sewing threads, each stitching comprising one or more plain stitches and one or more looped stitches concatenated to each other and ending with a free loop on a last one of the signatures of the block,
• a series of shuttles each for bringing a corresponding one of the sewing threads, downstream the corresponding plain stitches along a formation direction thereof, obliquely to an advancement direction of the blocks of signatures during the sewing thereof to an intermediate position aligned with the corresponding free loop along time advancement direction,
• a series of gripping devices each of bringing a closing portion of a corresponding one of the sewing threads from the intermediate position through the corresponding free loop along the advancement direction, the closing portion consisting of a portion of the sewing thread downstream the corresponding plain stitches along the formation direction thereof,
• a mechanism for actuating the gripping devices each to block the corresponding sewing thread at a gripping point comprised in the closing portion thereof,
• a series of cutters each for cutting a corresponding one of the sewing thread downstream the gripping point thereof along the formation direction of the plain stitches,
• the mechanism for moving the gripping devices, each of which blocks the corresponding sewing thread being brought through the corresponding free loop, to pull each the thread being cut by away from the corresponding free loop thereby tightening the free loop around the sewing thread being cut, and
• the mechanism for ceasing the actuation of the gripping devices each to release the corresponding sewing thread.