GB1096896A - Improvements relating to lens blocking - Google Patents

Abstract

1,096,896. Grinding. ACROPOL OPTICAL CO. Ltd. and H. G. WESTON-WHITE. Sept. 28, 1966 [Sept. 1, 1965], No. 37352/65. Heading B3D. [Also in Division F1] A lens blocking machine for mounting a number of spectacle lens blanks on the periphery of a runner 25, Fig. 1, for the grinding of their convex sides comprises a magazine 20 for the lens blank, a first conveyer which transfers a succession of blanks one at a time to a dispenser 21 which dispenses a small quantity of mobile adhesive on to the back of each blank in turn, and a second conveyer which conveys the blanks in turn from the dispenser to a fixing station having means 24 for pressing the blanks in turn on to the periphery of the runner. The first and second conveyers are formed as parts of a single carriage 19 consisting of parallel plates 33, Fig. 3, which are joined by spacers joined to spindles carrying rollers 37 running in a guide track 38. The carriage is connected by a block to the rod 20 of a pneumatic cylinder 42 and has steps 45 for engaging the lowermost blank 29 in the magazine 20, a tongue 28 supporting the blanks. The steps 45 carry the lowermost blank along a pair of guide rails 46 until it drops on to a second pair of guide rails 47 slightly lower than the rails 46. The blank is now disposed below the dispenser and is retained thereby the rails 46 as the carriage is returned to its initial position, the blank rocking as curved tips 48 at the leading end of the carriage pass below the blank. A measured quantity of molten wax, metal or adhesive is deposited on the back of the blank from the dispenser through a nozzle 22 and the carriage again advanced to simultaneously, by means of the curved tips 48 and steps 45, move the blank below the nozzle and the succeeding blank in the magazine along the rails 47, 46 to positions respectively above the cradle 23 of a ram 24 and below the nozzle 22. The ram 24 is operated to press the blank with the adhesive on its back against the runner 25 which is indexed in time with the movement of the carriage by actuation of a pneumatic ram 85, Fig. 9, having a rod 87 connected to a rack 81 engaging a pinion 83 of a one-way clutch 84 on the spindle 26 carrying the runner. The runner is clamped by a collar 69 against a roller bearing by the action of a pneumatic ram 73 acting through a yoke 75 to urge the collar towards the bearing. The rams for moving the carriage, operating the dispenser, actuating the cradle and indexing the runner are controlled by valves operated by cams on a common shaft, the shaft also driving through a crank a mechanism which determines the number of complete cycles of the machine and can be set to the number of lens to be mounted on the runner. In another embodiment the conveyers are in the form of a turret.