| 摘要 |
A triangle ruler includes a triangle ruler body defining three corners, three sides, opposing first surface and second surface surrounded by the three sides and three corners and a recessed annular scale located at the center thereof, and a direction indicator including a pendulum and a pointer and pivoting about the center of the recessed annular scale in such a manner that the pivot axis of the direction indicator extends perpendicular to the first and second surfaces of the triangle ruler body, and the effects of the weight of the direction indicator keeps one end of the pointer to constantly indicate a predetermined direction. Thus, the invention combines the functions of a conventional protractor and a conventional triangle ruler to facilitate drawing a variety of different angles of lines. |
| 主权项 |
1. A triangle ruler, comprising:
a triangle ruler body being a polygon with three corners and three sides, said triangle ruler body comprising opposing first surface and second surface, a recessed annular scale at the center thereof, and a circular opening surrounded by said recessed annular scale; at least one transparent protective cover mounted in said circular opening at one side, said protective cover comprising a plurality of engagement members, wherein said triangle ruler body further comprises a plurality of retaining lugs equiangularly spaced around said recessed annular scale and respectively hooked up with said engagement members of said protective cover; and a direction indicator comprising a pendulum and a pointer, said direction indicator being pivotally disposed in the circular opening, so as to pivot with respect to said recessed annular scale in such a manner that the pivot axis of said direction indicator extends perpendicular to said first surface and said second surface of said triangle ruler body, and the effects of a weight of said direction indicator keeps one end of said pointer to constantly indicate a predetermined direction. |
