| 摘要 |
The device comprises two rulers (1,2) located in a common plane. The rulers are pivotable relatively to each other around an articulation point located at two of their facing corners. The one ruler (1) supports a graduated plate (8) with its centre in the articulation point, whilst the other has a read-out component (9). So that the points of the angles formed between the rulers can be observed, and be accessible for a drawing instrument, the articulating point has a component (4) which extends in such a manner vertically that it terminates at a distance beyond the common plane for the ruler (1,2) lower locating surfaces. The component (4) is pref. a hinge with pins located in line with the vertical edge lines of the ruler facing corners. (Provisional Basic advised week 85/20) |
