摘要 |
An apertured rectangular foil of substantially inextensible sheet metal, e.g. nickel or steel, has a hole at each corner engaged by a resiliently biased gripper exerting on it a diagonally outward force to hold the foil stretched in a surrounding tenter frame supporting these grippers. The frame is provided with marginal ledges, underlying the foil at least along the major sides of the rectangle, onto which the foil edges are releasably pressed by toggle clamps.
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