Patent GB-808253-A (GB)
Title: Machine for shaping blanks of solid materials
Inventor: ASHENFELDER WARREN E
IPC: B24B13/00
Filed: 1957-03-25
Abstract: 808,253. Grinding lenses &c. NORTHROP AIRCRAFT, INC. March 25, 1957, No. 9663/57. Class 60. A machine for shaping a workpiece 66, such as a lens, comprises a base 10 and a column 12, a hydraulically-actuated reciprocable bed 16 on the base, a mechanically-actuated table 46 on the bed reciprocable in a path transverse to that of the bed, a hydraulically-actuated rotary pedestal 63 on the table connected to a vacuum line for imposing a vacuum to retain the workpiece thereon, a hydraulically and mechanically actuated ram 98 on the column, and a spindle 122 on the ram rotated by a hydraulic motor 122a and having a cutting tool 158 chucked thereto. The bed 16 is reciprocated by a hydraulic piston-and-cylinder device 31 under the control of a needle metering valve, a handoperated valve 26 and a reversing valve 42, which is actuated at the end of each stroke by pins 22 adjustable in a slide 18 on the bed 16, a handwheel 40 permitting manual adjustment of the bed to aid the setting of the pins. The table 46 is adjustable transversely of the bed 16 on guide-ways 44 by means of a micrometer hand-control 60 and, upstanding on the table, is the pedestal 63 which is rotated by a hydraulic motor 88 controlled by a hand-operated valve 170 ; a brake 96 retards rotation when desired, and the table and bed can be locked in selected positions by means of locks 56, 58. The workpiece 66 is retained on a grid in a plate 64 on the pedestal by a vacuum controlled by a valve 68 and is shaped by a diamond impregnated cutting tool 158 which is chucked to the hydraulically-rotated spindle 122 controlled by a hand-operated valve 164. The spindle is carried between arms 120 on the ram 98 and can be adjusted to any desired angle to the vertical by coarse, intermediate and fine adjustments 152, 154 and 156. The ram may be vertically reciprocated between pins 102, which are adjustably located on a slide 100 on the ram and cooperate with a trip valve 106 to reverse the direction of the ram, under the control of a hand-operated valve 124 ; a handwheel 112 provides means for moving the ram to set the pins. Vertical reciprocation of the ram may be controlled by a follower 184 which is connected to the ram and engages a template 186 carried on the bed 16. Vertical movement of the ram may also be controlled hydraulically by a handle 148, mechanically by a manual drive 149, or by a hydraulic valve 150 which automatically lowers the ram a small amount after each complete cycle of movement of the bed 16. The weight of the ram is counterbalanced by weights suspended from chains 144 guided over sprockets 146. Coolant is supplied through the spindle 122, which is hollow, and discharges from the centre of the tool, and may also be supplied direct to the workpiece. The coolant is collected in a container 78 from which it drains into a trough 82 and returns to be recirculated. Accordian covers 54 are provided to protect the guidsways 44. The machine is mounted on a plurality of feet 14 which incorporate strain gauges to indicate strains which may develop in the machine frame and cause inaccurate work.