| 摘要 |
The supporting wire is of non-circular cross section and curved to form two roughly U-shaped symmetrical portions (2, 3) with adjacent central branches (2a, 3a), which are shorter than their outer branches (2b, 3b). The central branches are joined by an inverted U-shaped curve, the base (7) of which is situated some 25 mm below its upper end, which forms an angle of between 3 and 10 degrees with the vertical. The tips of the two outer branches (2b, 3b) lie between about 15 and 25 mn above the top of the central curve. The supporting wire is of oval cross-section, is curved by means of rollers, and fixed in shape by stoving at 190 deg C for 35 min.
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