| 摘要 |
This frame, comprising for each of the lenses to be supported an open metallic eye-piece and of which the ends are adapted to abut one against the other by means of a mutually screwing member is characterized in that the two ends of the metallic eye-piece cooperate with a common guiding groove provided in a connecting lug so that, by relative engagement of its ends in the groove, they are perfectly aligned one in the extension of the other.
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