Patent GB-100388-A (GB)
Title: An Improved Process and Apparatus for Grinding Lenses.
Inventor: BROCKBANK JOHN
IPC: B24B13/00
Filed: 1916-02-25
Abstract: 100,388. Brockbank, J. April 30, 1915, [Convention datel. Lenses, grinding and polishing.- Lenses are produced by rubbing together two lens blanks, one of which is moved in an arc whose centre is in the common axial line of the blanks, abrading &c. material being introduced between them. Two blanks 56, 70 are mounted on coaxial spindles 47, 72. The frame carrying the spindle 47 is always cscillated about a transverse axis, but the block 74 carrying the spindle 72 may be reciprocated transversely, and one or both or neither of the spindles may rotate. By selecting the motions to be imparted to the spindles, any curve may be produced. The spindle 47, in the arrangement shown in Figs. 1 and 3, is connected by bevel-gearing and intermediate shafts 41, 37 to a main shaft 33. One gear may be slid out of mesh when rotation of this spindle is not required. The spindle is adjustable in its supporting-frame 45 to give the required radius to the arc in which the blank 56 swings, and the frame 45 has a bearing-boss 43 which is oscillated by an arm 57. This arm is rocked by a rod 58 adjustably connected to a crank-disk 61, which is rotated by gearing from the shaft 33. For setting the spindle 47 to swing in the required arc, an adjustable radius pointer 103 is provided against a scale 104 on the frame, and a pointer 107 on the arm 57 moves over a fixed scale 105 to indicate the field of swing. The lower spindle 72 is driven by a flexible cable 122 through a universal joint 121, and has an adjustable stop-collar 78 and a spring 77 for keeping the blanks 56, 70 in contact under pressure. The block 74 supporting the spindle 72 is mounted on a transverse slide 75, on which it may reciprocate or be clamped by a screw 82. The block 75 is vertically adjustable in the frame 31. The block 74 is reciprocated by a rod 83 adjustably connected to a crank-disk 86, which is rotated by gearing from the main shaft 33. One gear may be slid out of mesh when reciprocation of the block 74 is not required. When the spindles are not rotated, they are locked by screws 123, 125. In the modification shown in Figs. 7 and 8, which is suitable for grinding surfaces of short radius, the lower spindle 72 is mounted and actuated as before, but the carrier 109 for the upper spindle 47 is pivoted at 108, and the spindle is driven by a fiexible shaft 112 through gearing 48, 49. The carrier is caused to rock about the pivot 108 by a spring 117 stretched between a pin 114 on the carrier and a pin 116 on the frame. An adj ustable stop 118 limiting the swing is provided on the frame. The carrier rocks only once in each grinding operation. The spring may be stretched between the pins 113, 115 when it is desired to rock the carrier in the other direction. The blanks 56, 70 are secured to the face-plates 55, 71 by pitch or the like. The Specification as open to inspection under Sect. 91 (3) (a) comprises also the use of a block of abrading material instead of one of the lens blanks. This subject-matter does not appear in the Specification as accepted.