Patent GB-190612995-A (GB)
Title: Improvements in Machines for Grinding the Surfaces of Lenses.
Filed: 1906-06-05
Granted: 1906-12-06
Abstract: 12,995. Long, E. M., and Standard Optical Co. June 5. Lenses.-Toric, cylindrical, and other lenses, or curved surfaces of different radii, are held in a work-holder which moves in successively differing serpentine paths over a stationary lap upon which emery &c. powder is sprinkled, the working parts of the apparatus being enclosed in a casing to prevent the emery dust &c. from clogging and wearing the gearing. The lens 3, Figs. 4 and 6, is attached by cement or otherwise to a metal plate 2, and is moved over the grinding bed or lap 1, which is removably mounted on the stationary arm 4. Motion is transmitted to the lens holder 2 through an arm 9 to which is pivoted a yoke 7, which is jointed to the plate 2 by pins 12 engaging with holes in the plate. A spring 11, confined between a fixed block 14, adjustable along a rod 19, to vary the tension of the spring, and a collar 15 on a rod 10, presses the lens against the lap. The tapered end of the rod 10 fits into a hole in the yoke 7. The rod 10 parses loosely through a hole in the block 14 to allow of its oscillation, and a pin 18 limits its downward movement. The rod 10 and yoke 7 are loosely joined by a link 16 so that they may be lifted to remove the lens. The link 9 is connected to a frame 19, which can swing about an horizontal axis 20, Fig. 3, and also about another horizontal axis 21, Fig. 4, perpendicular to the axis 20, and in the same horizontal plane. The oscillation about the axis 20 has a greater amplitude and a lower frequency than that about the axis 21, thus imparting to the lens holder a serpentine motion over the lap 1. One end of the axis 20 is attached to one arm 22 of a bell-crank lever pivoted at 23 to a fixed upright 24. The other arm 25 of the bell-crank embraces a short spindle 26 in which is a socket 27. A pin 28 eccentrically carried by a pinion 29 on the top of a driven shaft 30 fits in this socket. The rotation of the shaft 30 thus produces an oscillatory motion of the frame 19 about the axis 21 which is transmitted through the arm 9 and yoke 7 and gives a quick short movement to the lens across the lap. The pinion 29 gears with a wheel 29', Fig. 3, upon which is removably mounted an eccentric 32, locked in position by a set-screw. The eccentric is journaled in an annulus 34, to which is attached a link 35 joined by a ball-and-socket joint 36 to the lower part of the frame 19. The frame 19 is thus given an oscillatory motion about the axis 20, and this imparts to the lens a slow long movement along the lap. The composition of the two movements gives a serpentine motion to the lens, and, as the number of teeth in the gear 29<1> is not an exact multiple of the number of teeth in the pinion 29, the path of a particular point on the lens is continually changing, and grooving &c. is obviated. The whole of the working parts are enclosed in a casing 37, 38, the upper part 38 of which is removable and attached by screws 39.to the lower part 37. The spindle 30 is journaled in a bushing 41 carried by a hub 40 depending from the casing. Oil cups 42 with leads are provided in the casing. The presence of the hub 40 allows the apparatus to be clamped in place upon any similar machine and applied to any available rotary shaft or spindle.