GB991801A - Improvements in and relating to lens edging machines - Google Patents

Abstract

991,801. Bevelling lenses. H. J. STRUNCK. April 30, 1962 [April 29, 1961; Jan. 11, 1962], No. 16416/62. Heading B3D. A machine for bevelling lenses comprises means for mounting two or more lenses coaxially with a template for rotation therewith, one or more followers co-operating with the template for controlling a table or tables carrying the bevel-producing grinders, and means whereby the ground lenses are ejected and replaced by unground ones. In the embodiment of Fig. 1, the template 2 is held between the manuallyadjustable jaws 8 of a divided shaft 4 and two lenses 9 are held between the jaws 8 of divided shafts 6, 7 arranged coaxially with the shaft 4 and driven by the same motor which drives the shaft 4; hydraulic cylinders 11 move the shafts 7 axially to operate the jaws 8. Mounted on opposite sides of the template and lens assembly are two tables 12, 13, each of which carries a follower 14 comprising a cylindrical portion 14a and conical portion 14b providing an edge 23 to engage the apex of the double-bevel rim of the template 2; lateral adjustment of the follower relative to the template is effected by a screw 22. Each table also carries two motor-driven grinding wheels 15 coacting with the respective lenses; as shown, two grinding wheels act on each double-bevel lens to produce the different bevels. Hydraulic actuators 19 reciprocate the grinding wheels across the bevelled edges of the lenses during grinding. Each table 12, 13 is carried by double rollers 25, Figs. 2 and 3, which are displaceable along rods 26 mounted on vertical supports 27 on a rod 28 pivotally supported in the machine frame. A spring 35 and a weighted arm 29 urge each table so that the follower bears against the template and hydraulic actuators 31 are provided whereby the follower and grinding wheels may be swung out of contact with the template and lenses to permit lens changes to be made after grinding. For the latter purpose, a vertically-movable fork 36, Fig. 5, is mounted under each grinding station so that, when moved upwardly by an hydraulic actuator, grippers 38, 39 are moved inwardly by cams to grip an unground lens in a box 45 disposed over the station and rubber grippers 41, 42 grip the ground lens 9a held by the jaws 8. Downward movement of the fork following opening of the jaws then positions the ground lens for ejection and the new lens for grinding; if desired, the grippers 38, 39 may be replaced by rubber grippers similar to the grippers 41, 42. The control circuit of the machine provides for the automatic timed operation of the hydraulic actuators of the forks 35, cams for the grippers 38, 39, means for ejecting finished lenses from the forks 38, the hydraulic actuators 11, 19, 31 respectively operating the jaws 8, grinding wheels 10 and tables 12, 13 and means for moving the box 45 to enable it to be charged with new lenses. In a modification, Fig. 6 (not shown), cylindrical followers on the opposite tables contact the different bevel edges of the template and effect only a lateral movement of the tables. In the further modification shown in Fig. 7, a follower 14 is displaceably and swivellably mounted on a table 12 so that it may be swung to engage first one of the two bevel edges of the template 2 and then the other, the grinding wheel 15 being similarly swivellable so as to be correspondingly set for the successive grinding of the two bevels of the lenses. Fig. 10 shows another embodiment in which a compound motion of each of.the tables 12, 13 is effected by the use of two templates, namely a cylindrical member 2a co-operating with the followers 14 and a face cam 51 on the frame coating with a follower 50 on the table. In another embodiment, Fig. 8 (not shown), two rotary cylindrical templates are respectively engaged by followers to cause lateral movement of the table.