Sample book binding device, has screw with through hole, which opens out into boring that is provided in screw head, so that passage channel for accommodating ball thread is formed in screwed condition

摘要

The device has a screw with a screw head (11) and a threaded pin (14), which is integrally formed at the screw. A casing receives the screw, and a casing part comprises an internal screw thread. The screw and the casing have a through hole along its rotation axis. The through hole opens out into a boring (12) provided in the screw head, so that a passage channel for accommodating a ball thread is formed in the screwed condition.