| 摘要 |
<p>An expandable artists' frame (20) with preloading springs (26) therefor, wherein the frame sides (21) are slidably connected together at their ends by means of an optional groove-and-tongue joint or a hollow angular support and the preloading springs (26) have a strip-like body (27) with toothed ends (28). For mounting a spring (26), the latter is placed diagonally with its teeth (31) against a frame corner on the internal surface (43) thereof and then the spring (26) is pushed manually toward said frame corner. During the spring application the spring teeth (31) slide on said side internal surfaces (43). When stopping the thrust onto the spring (26) the teeth (31) penetrate into the wooden side (21) and exert a continuous preloading action on both adjacent frame sides (21). At the spring ends are preferably provided positioning and protection wings (36).</p> |
