Patent GB-512104-A (GB)
Title: Improvements in and relating to machines for grinding the edges of plates, such as lenses
IPC: B24B9/14
Filed: 1938-11-30
Abstract: 512,104. Grinding lens &c. edges. JORDAN, A. T.,_ and LEVER, P, Nov. 30, 1938, No. 34871. , [Class 60] A machine for grinding the edges of lenses or other plate- or disc-like articles, either flat or bevelled, comprises a number of sections, each having two grinding-wheels 1, a pair of grippers 2 for the lenses, and a single chuck 3 for a former having the shape to be given to the lenses, the grippers and the chuck being mounted coaxially on a common shaft 4. The shaft 4 rotates in arms 5 of a swinging frame 6 mounted by means of rearward arms 7 on a main shaft 8, which is journalled in brackets 10 on a standard 11 of the frame 12. Each grinding-wheel is independently mounted on a bearer 15 as an interchangeable unit 13 and is driven by a pulley .14 from a shaft 18, which is driven from a motor 16, and also by a drive 20 and gearing 21 drives the shaft 8. The carrier shaft 4 is composed of a number of axially separable parts, the centre part having thereon a pulley 22 provided with pins 23 which may enter holes in a chuck part 24 of a shaft part 25 so as to pass through corresponding holes in the former 26, which is held between the shafts when brought together. The carrier shaft also has end parts 27, driven synchronously with the shaft 4 by gearing 43, 44, each carrying the elements 28 of the lens grippers, the complementary parts 29 of which are carried by the shafts 4, 25, and the parts 27 are urged inwardly by springs 30, the parts being movable against the pressure of the springs by handles 32 pivoted to the frame 6 at 33. The pulley 22 is driven by a belt 36 from a pulley 37 loose on the shaft 8 and adapted to be driven thereby through a clutch 38. The lenses are fed into the grinding-wheels by lowering the pivotal frame 6, the mechanism for this purpose comprising a cam 45 on which rests a roller 46 carried by an assembly 47 on which is mounted a block 84 engaged by the former 26 during grinding. The cam is fixed to a ratchet wheel 48 actuated by a pawl 49 on the end of the rod 50, which is slidable in a guide block 51 pivoted at 52 to the frame and 'pressed by a leaf spring 55. The rod 50 is pressed by a spring 56 engaging a collar 57 on the rod, and the effective stroke of the rod is adjustable by a screwed rod 59 carrying a collar 58 forming a forward abutment for the collar 57. The rod is actuated to turn the wheel 48 and cam 45, by a lever 65 pivoted to the member 51 and engaging at its lower end with a collar 67 on the rod, the upper end of the lever being moved by a tripping member 64 mounted on the pulley 37. When the former block 84 has been lowered sufficiently by the cam 45 to complete the grinding operation, a stop mechanism is operated to lift the former from the block, and the lenses from the grinding- wheels. This mechanism comprises a bell crank lever 74 pivoted at 69 to a standard 70 and normally resting on a stop 76. The arm 71 of the lever is moved by a radial arm 73 on the cam 45 when grinding is completed, and this moves a roller 75 on the lever into the path of the member 64, whereby the lever is lifted so as to strike an abutment 78 on the frame 6, lifting this until held by a notch 80 in a spring-pressed lever 81. The former block 84 is adjustable by means of a screw ring 92 and an adjustable mounting 90 to suit the size of the work and the former. Each grinding-wheel unit consists of a T-shaped member 13 with a spigot 96 rotatably and slidably adjustable in a socket 97 on a bracket 98 clamped to the bearer 15; the spigot is adjustable vertically by a screw 99 and is clamped by a screw 100, and each unit is removable for resurfacing the wheel and the units are interchangeable. The. wheels may have flat peripheries or V-grooved peripheries, in which case they may consist of two bevelled wheels placed face to face. The wheel-spindles may be free to move axially to a limited extent or may be reciprocated axially positively by cam mechanism to ensure uniform wear of the wheels; water is supplied to the wheels during operation.