Patent 7246960 was granted and assigned to Citizen Watch on July, 2007 by the United States Patent and Trademark Office.
A needle guide (5) is composed of a first guide wall (5a) and a second guide wall (5b) arranged at a distance x from each other. Each of these guide walls is formed with through holes through which needles penetrate and which extends parallel to the longitudinal direction of a needle bunch, the through holes of the first guide wall and the second guide wall for one needle is shifted from each other in the convergence direction of the needles with a shift amount δn determined by the distance x and a convergence angle θn of the needle.