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Method and device of the embodiment of the surfaces of the fresnel
Method and device of the embodiment of the surfaces of the fresnel
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机译：菲涅耳表面的实施例的方法和装置
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678,916. Copy-turning; planing. PHILIPS ELECTRICAL, Ltd. June 15, 1948 [June 18, 1947], No. 16081/48. Class 83 (iii). [Also in Groups XVI and XXIII] Apparatus for manufacturing a Fresnel surface comprises a table 2, and a slide 7 which carries a tool and holder 8 and is mounted on a support 3, the tool-holder forming part of an articulated rod system comprising a guide rod 11 having two pivots 13, 15 positioned to correspond to a main ray on that part of the surface worked by the tool, the tool having a pivot 9 coinciding substantially with the tool edge 16, and the guide rod 11 having an extension A-B which controls the position of the tool-holder. The tool may be a chisel or a grinding or polishing wheel. The table 2 is rotated to form circular surfaces or reciprocated to form cylindrical surfaces. Alternatively, the table remains stationary and the tool-support is moved. An arm 4 of the tool-support 3 carries the sliding block 7 which is adjusted between cuts by a screw or piston rod. Pivoted to the block 7 is the arm 11, one end of which slides in a block 14 pivoted at 15 on the axis XX of the work, and the other end of which carries a pivot to engage a slot in the end of the tool 8. The cutting edge 16 is at right angles to the centre-line of the tool. The pivots are positioned so that the dimensions being indicated on Fig. 3, and a/b is made equal to the refractive index of the material. Specification 501,645, [Group XVI], is referred to. The Specification as open to inspection under Sect. 91, states that the work may be of highly transparent artificial resin or reflecting material, or, if it is to be used as a matrix for making casts or prints, of wax or metal. Further, Fig. 4 (Cancelled), shows a linkage for producing a reflecting parabolic surface. Pivots 22 and 9 lie on a line parallel to the axis XX and links 19, 20 maintain the tool in a position bisecting the angle between the said pivots and a rod 11 passing through the focus F. Fig. 5, (Cancelled), illustrates the linkage for cutting a reflecting spherical surface or, approximately, the matrix for a convex lens. The apparatus shown in Fig. 7 (Cancelled), is modified to cut the inactive surfaces. A cutting- edge is provided on the side of the link 11 passing through the focus F. For greater accuracy, the pivoting point D is determined by the centre of a circular guide 26 along which the tools are guided. For finite distance of an object, the second tool is provided by an additional rod passing through a point B, Fig. 8 (Cancelled), representing the object. A separate tool 8, Fig. 9 (Cancelled), may be provided and controlled by a rod 8a. This subjectmatter does not appear in the Specification as accepted.
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