| 摘要 |
<p>A protractor and three bars assembled into a variable right-angled triangle are used in mechanically joining the combined timbers of a roof structure. On the inclined bar (1) carrying a transverse scale (7) there is an additional mounting bar (8), bearing the lengthways scale and displaceable and fixable lengthways and crossways. The mounting bar (8) is movable lengthways across the zero point of the base bar, and its bottom end can be brought against a lug slide (6), as stop, which slides on an extension bar (5) on the base bar, with opposite-direction scale. This also makes provision for transverse dimensions in the plane of the roof profile.</p> |
