骑马订书机包括用于输送书贴的缝合工位（24），至少一个折叠薄片进给器（10，12，14），一个bezügüch传输和Heftünie（22）后部主集电极链（50）和相关的前辅助集电极链（40）（16， 18，20）沿着所述输送和缝合线（22），其沿着所述折叠的片材进给器（10，12，14）和（通过缝纫台24）延伸。 主，辅集电极链各自包含连接到这些屋顶和载体链节和链。 主，辅集电极链在平行折叠的片材馈送器的区中的至少延伸，留下在运输和缝合线折叠片材进给器的面积后的辅助集电极链（22）下方偏转，使得在缝合工位（24）的区域中，只有主集电极链 （50）沿着输送和缝合线（22）。 主集电极链（50）由电动机驱动。 用于经由前部和后部链轮，它们彼此连接，辅助集电极链（40）的驱动器接合在辅助集电极链（40）和在所述上分支后链轮（52）的前链轮（在缝合站24的方向 ）当前后部主集电极链（50）与后链轮（52）具有一个灯笼齿轮啮合。

A saddle stitcher has a stitching station (24), at least one folded sheet feeder (10, 12, 14), a bezügüch a transport and Heftünie (22) rear main collector chain (50), and a related front auxiliary collector chain (40) for transporting signatures (16, 18, 20) along the transport and stitching line (22), extending along the folded sheet feeder (10, 12, 14) and through the stitching station (24). The main and side gathering chains each have chain links and on these fortified chain roofs and driver. The main and side gathering chains run at least parallel in the folded sheet feeder, said auxiliary collector chain after leaving the area of ​​the folded sheet feeder from the conveying and stitching line (22) is deflected by, so that in the stitching station (24) only the main collector chain (50) extends along the conveying and stitching line (22). The main collector chain (50) is driven by a motor. The drive for the auxiliary collector chain (40) via a front and rear sprocket, which are connected together, the front sprocket in the auxiliary collector chain (40) engages and the rear sprocket (52) in the upper run in the direction of the stitching station (24 ) free rear main collector chain (50), wherein the rear sprocket (52) has a rack and pinion gearing.