GB1138970A - Method of and apparatus for producing a spectacle lens bevel - Google Patents

Abstract

1,138,970. Grinding. WERNICKE & CO. K.G. 12 April, 1966 [9 April, 1965], No. 15814/66. Headings B3D and B3K. A device for producing a spectacle lens bevel which runs along a solid curve having co-ordinates situated at right-angles to the lens surface comprises a follower which is rotatably but non- axially displaceably mounted on the shaft of a bevel grinding wheel and engages the inner side of a spectacle frame, or a pattern formed using the lens, mounted on a shaft carrying the lens for displacing the bevel grinding wheel in a direction parallel to the axis of the shaft. The lens blank R is initially mounted between the parts 5, 6 of a work holder on shafts 1, 7, shaft 1 carrying a template 4 corresponding to the desired shape of the lens and being driven by a motor 3, and shaft 7 having a collar 8 carrying a pattern 9 having an annular flange 11 which is to be formed to the contour of the solid curve of the lens. The template 4 is engaged by a follower 16 on a shaft 13 which is rotatable by a motor 17 and is aligned with a shaft 14, the shafts having couplings for connection to a shaft 15 carrying a wheel 19 for grinding the periphery of the lens. After the initial grinding of the periphery of the lens, the grinding wheel 19 and shaft 15 are replaced by a feeler disc 28, Fig. 2, and shaft 27, and a milling cutter 35 is mounted on a motor 24 carried by an arm 22 rotatably, but not slidingly, mounted on the shaft 14. The feeler disc 28 has a raised centre part 29 forming recesses 32, 33 which are selectively engageable with the edges T 2 , T 1 of the rim S of the ground lens G and control the axial displacement of the disc 28 and hence movement of the milling cutter 35 during rotation of the lens to form a contour 36 on the pattern 9 corresponding to the solid curve of the lens. Springs 26, 26a urge the disc in one direction or the other and, during forming, the template 4 may be disengaged from the follower. Thereafter, the bevel is ground on the lens by replacing the disc (28) and milling cutter (35) with a grinding wheel (39, Fig. 3) and follower (37), the latter engaging the contour of the pattern (9) to move the grinding wheel (39) axially during rotation of the lens so as to follow the contour of the lens. In another embodiment, the shaft (7, Figs. 6 and 7) has an extension (69) on which the spectacle frames (62) are mounted in a holder (60, 61). A feeler (64) which is on a bush (66) slidable on an arm (67) extending from the shaft (14) and is urged by a spring (68) against the inner edge of the frame, controls the axial movement of the grinding wheel (39) during rotation of the lens and frame, the movement of the grinding wheel in its plane being controlled by the template (4) and follower (16). In a similar embodiment, the template and follower (14, 16) are omitted and the movement of the grinding wheel in its plane as well as axially are controlled by the feeler engaging the inner rim of the spectacle frame.