| 摘要 |
<p>The frame comprises sections of shape (1, 2), in the recesses of which are inserted an insert (3, 3 min ) that forms an angle at the corners.
<??>Each insert exhibits a notch (4, 4 min ) in which the bent end of a square spring (5, 5 min ) fits, the spring is solid at the other end with a block (6, 6 min ) that can slide in a guide (1 min , 2 min ) of the shape and is provided with a tension screw (7, 7 min ).
<??>By the screw being tightened, the sections of shape (1, 2) are thrust outward, leaving a space (10) between them, and causing the stretching of the canvas. </p> |
