| 摘要 |
<p>The square has a set square unit (10) and a scale (11), and a plastic frame (13) that is provided with a trigger (16) and a hook-shaped holding latch (17) for ensuring double locking of the scale on a positioning stud (30) fixed on the frame. The scale is provided with an elongated hole (24) extending longitudinally in a central part. The hole is traversed through the positioning stud to ensure guidance of the scale.</p> |
