GB1327732A - Method and machine for grinding spectacle lens edges - Google Patents

Abstract

1327732 Grinding WERNICKE & CO KG 27 Jan 1972 [27 Jan 1971] 3859/72 Heading B3D A method of grinding the edge of a non-circular spectacle lens comprises rough grinding the edge with a first grinding wheel 29, effecting axial movement of the first grinding wheel, a smoothing cut second grinding wheel 30 and a driving spindle 3 of the wheels to bring the second wheel into alignment with the edge of the lens, the second wheel or a member 19 associated therewith being held against a stop 17 on the spindle during the axial movement, engaging the lens with the second wheel, releasing the second wheel from the stop and effecting axial movement of the spindle to move the stop clear of the second wheel, and grinding the edge by means of the second wheel, the wheel undergoing axial movement and the lens undergoing rotation but no axial movement during the grinding. In apparatus for carrying out the method, a housing 1 is movable in the direction of the arrows A by a distance X or Y together with a prime mover which is connected by a belt drive to a pulley 11 on the spindle 3. One end of the spindle is mounted in a bearing 4 in the housing and a further bearing 9 in the housing is pressed against a flange 8 on the spindle by a nut 14 which presses the pulley 11 against the bearing. A nut 15 secures one end of a flexible seal 16 against the nut 14 and a collar 17, which acts as the stop, is also screw-threaded on the spindle. A sliding ball bearing 18 supports a bush 19 on the spindle for movement in the direction of arrows 13 and the bush has a pair of slots 20 engaged by rollers 21 on a cross-pin 22 whereby it is normally movable but constrained to rotate with the spindle. A sleeve 23 is secured to the bush and a shroud 24 is clamped to the sleeve and retains the other end of the seal 16. An end face 26 of the sleeve is acted upon by the rod 27 of a solenoid 28, the rod being supported by ball bearings in the solenoid. The rough cut grinding wheel 29 and two smooth cut chamfering wheels 30, 31 are mounted on the sleeve. In operation, the solenoid is actuated so that the bush 19 abuts the stop collar 17 to position the wheels so that the edge of the lens is ground by the rough out wheel 29. After rough grinding, the lens is lifted from the wheel and the housing is moved to the right a distance X or Y to align the groove 34 or 35 in wheel 30 or 31 with the lens which is then engaged with the groove. The solenoid is then actuated to retract the rod 27 12 mm. to the right at the same time as the housing 1 is moved 6 mm. to the left to disengage the stop collar 17 from bush 19 so that the bush and wheels are free to axially follow the lens edge as the lens is rotated. The solenoid may be replaced by a spring rendered ineffective during the smooth grinding operation.