| 摘要 |
The invention relates to a drawing compass with legs 1', 1'' which are guided automatically and symmetrically relative to one another, and which are guided parallel to each other in a substantially linear manner when the drawing radius is set. The compass handle 9 remains approximately at the same height relative to the plane of drawing Z for all set drawing radii. According to the invention, two six-membered guide mechanisms 1 to 6 each guide a leg 1' or 1'' of the compass as a coupling member of a jointed parallelogram 1, 2, 3, 4 on the common slide 3 of two sliding crank mechanisms 3, 4, 5, 6, whose cranks 5 each engage on the connecting rod 4 of the jointed parallelograms 1, 2, 3, 4 which faces them. Exactly linear parallel guidance of the two compass legs 1', 1'' is obtained if the sliding crank mechanisms 3, 4, 5, 6 are equal-sided and central and each engage by their linearly guided coupling point 11 on the associated compass leg 1' or 1''. With these dimensions of the guide mechanisms, a force acting from above on the compass handle 9 cannot cause any movement in the guide mechanisms 1 to 6. The slide 3 therefore does not need to be fixed and nevertheless remains stable in the preselected position. For the drawing of small circles, the jointed rectangles 1, 2, 3, 4 may deviate slightly from the parallelogram shape in that the two legs 1', 1'' automatically, that is to say of their own accord, incline towards each other when small drawing radii are set. <IMAGE>
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