Patent GB-493182-A (GB)
Title: Improvements in milling, surface grinding and like machine tools
IPC: B23C9/00
Filed: 1937-12-21
Abstract: 493,182. Grinding-machines. REINECKER AKT.-GES., J. E., and SAUPE, M. Dec. 21, 1937, No. 35323. [Class 60] [Also in Group XXII] A surface-grinding or like machine tool has a work-table and a tool which may be relatively fed in longitudinal and transverse directions by two separate reversible electric motors which are automatically started, stopped and reversed in the required sequence by switching means comprising two electromagnetic master switches whose magnet circuits are controlled by switch mechanism operated by keys on the table to perform a closed cycle of operations. In a doublecutter machine the work-table 1, Fig. 1, is reciprocated by a reversible electric motor 3, and tool heads 2, 2<1> carrying milling-cutters 16, 16<1> are arranged to slide on adjustable cross rails 14, 14<1> which are vertically adjustable on columns 13, 13<1>. The transverse feeds are actuated by screws 15, 15<1> driven by reversible electric motors 4, 4<1>. A work piece such as a Diesel engine block shown in Fig. 11 may be milled by successive relative transverse and longitudinal movements of the work and tool slides. Thus the cutter 16 first moves in direction 19 to position 20, then the table moves in direction 21 until the cutter reaches point 22, the cutter moves from 22 to 24 and finally the table moves from 24 to 26 at which point the machine is stopped. The cutter 16<1> performs a similar cycle. Similarly the sides of a block 18<1> and a rectangular flange 18<11> at the base thereof may be milled by a side-and-end milling-cutter 16<11> moving relatively over the chain line path in Fig. 9. The control circuit for performing the cycles of Fig. 11 is shown in Fig. 3. The cutter motors 4, 4<1> supplied by mains R, S, T, are driven in one direction when electromagnetic switch a<1> is closed and in the opposite direction when switch a<2> is closed. Similarly the table motor 3 is driven in opposite directions by selectively actuating the electromagnetic switches a<3>, a<4>. These switches are operated by coil circuits S<1>, t<1> .. s<4> t<4> which are controlled by two-way switches 6.. 8 and oneway switch 9, the latter being normally spring- closed and the switches 6 .. 8 being spring urged towards the positions shown in Fig. 3. Dogs 29 ..31 control the table movement and other dogs 10, 30 control the cutter movements. In operation after setting the dogs to give the required longitudinal and transverse travels, a starting switch 35 is closed, thus closing switch a<1> and starting the crossfeed motors 4, 4<1> which run until the dog 10 throws over the switch 6, breaks circuit s<1>t<1> and completes the circuit s<3>t<3> thus closing the switch a<3>. The table motor 3 then operates the longitudinal table feed which continues until. dog 29 throws switch 7 and completes circuit s<2>t<2> to close switch a<2> and start the cross-feed motors in reverse direction. At the end of this movement the dog 30 throws switch 8, completing the circuit s<4>t<4> and starting motor 3 for the longitudinal return feed. When the points 26, 26<1>, Fig. 11, are reached the dog 31 opens the switch 9 and stops the cycle, which may be operated by again closing the switch 35. In a modification, Fig. 15, a knee type milling machine has both feeds imparted to the work, the longitudinal and transverse feed movements being operated by motors 3<11>, 4<11>, respectively, controlled by dogs coacting with switches as described above. The switches may be of the form shown in Fig. 12. A bar 39 secured to the member 44 carrying the contact plate is secured by a spring 38 to one end of another lever 36 pivoted at 37 and urged to maintain the switch in the full line position by a spring 42. When actuated by the dog 10, the arm 36 is moved to the dotted line position to effect the change-over.