| 摘要 |
An apparatus for assisting in the measurement of angles and, in one particular form, for the calculation and measurement of angled cuts and lengths of structural components required in the construction of roofs. The apparatus essentially consists of a flat body (4) which resembles a protractor. The body has two straight rule edges (2, 3) at 90 DEG to each other. A movable bar (5) is included which is pivotally attached to the corner formed by the two straight rule edges (2, 3). The movable bar (5) is movable between positions parallel to each of the straight rule edges (2, 3). At least one scale is included on the flat body of the apparatus. The or each scale has divisions representing an angle or line of cut for a rafter or other building member, measured between the movable bar (5) and one of the straight edges (2, 3). |
