| 摘要 |
The invention relates to a didactic device for representing various geometrical places, consisting of some graduated rules (3, 4, 11, 12, 39, 40 and 42), some rectilinear bars (1, 2, 7, 8, 9, 15, 19, 20, 24, 25, 26, 27, 28, 29, 30, 36, 37, 45 and 46) and some circular bars (14, 34 and 35), situated at various angles between them, some of them being reinforced between them, in some points (a, b, c, d and e) or on a plate (33), or they are provided with some grooves (h), some longitidinal cut-outs (f) and some orifices (g), some of the bars having some clamping elements (22, 32, 41, 43 and 49), some unextensible threads (48), some handles (44 and 50), on the bars there may slide a square rule (47), the said bars may rotate or slide along one another, due to some rings (6, 13, 18, 31 and 38), some sleeves (10 and 21) or some guides (5 and 16).
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