| 摘要 |
The trammel is intended for drawing big circumferences and may be applied in construction and education, as well as in machine building in lining pieces. The trammel is very stable and as a result - is highly precise in lining. It consists of a centering rod (1), connected with a rigid holding bar (4), on which slippingly are put a bearer (5) of the writing agent (6) and a supporting bloc (7), connected regulably in between via a leading pin (10) and a micro-metric screw (11). To the support bloc (7) are envisaged a fixing handle (9) and in the bottom, below it, a third interchangeable support (8), whose edge may end with a roller, a ball or may be spherical.
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