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Toothing device for wood connections, in particular can be used on saws
Toothing device for wood connections, in particular can be used on saws
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机译:用于木材连接的磨齿装置,特别是可用于锯
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摘要
729,667. Optical objectives. BERTELE, L. Oct. 16, 1952 [Oct. 24, 1951], No. 25952/52. Class 97 (1). In an optical objective having three members of which the first member is a simple positive lens L1, the second member is a negative meniscus triplet L2, L3, L4 convex towards the object and the third member is a positive doublet L5, L6 having a cemented surface r8 convex towards the object, the air space between the front lens and the triplet being of the form of a negative lens and the other air space being of the form of a positive lens with its lens curved face on the image side, the positive lens L6 of the doublet has a refractive index at least 0.18 greater than that of the negative lens L5 and the radius of curvature of surface r8 is between 0.5 and 0.85 times the equivalent focal length. Specifications 681,456 and 692,013 are referred to.
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