Patent GB-541548-A (GB)
Title: Automatic device for controlling grinding and other machining operations
IPC: B24B49/18
Filed: 1940-04-01
Abstract: 541,548. Planning; gauging-devices. DUDGEON, H. A. April 1, 1940, Nos. 5788/40, 6995/40, 15852/40 and 714/41. [Class 83 (iii)] [Also in Group XXIII] A sizing device for controlling the operation of a planing or grinding machine comprises a freely rotatable control wheel which is automatically rotated by contact with the tool at a predetermined stage of the operation. In a grinding machine, a micrometer 2, Fig. 2, is mounted on an arm 3 pivoted to a base 6 adjacent the work piece 4 being ground internally by a wheel 5, the member 6 being longitudinally adjustable on a longitudinally movable table 7. The micrometer may be set so that when it reads zero its free end 2a is on the axis a of the work and the graduations of the micrometer indicate twice the actual movement of the spindle 2a Another pivoted arm 10 on the base carries a spindle 11 adjusted axially by a nut 12 and secured by a screw 16. This spindle carries a loose block 17 fitted with a free control wheel 18. The control wheel spindle is slightly inclined to the work axis so that the wheel' moves axially when it engages the grinding wheel which is usually arranged to occur when the work has been ground to size. This axial movement of the control wheel may be arranged to operate a machine control or to ring a bell or light a lamp. For this purpose the block may carry a contact plate 31 fitted with a contact 34 on which the spindle 19 bears when moved axially. Alternatively the axial movement may break a circuit or change over circuits to change the operation of the machine. When it is desired to grind a hole of 1 inch diameter the micrometer is set to read 1 inch which projects its spindle ¢ inch beyond the work axis. The block 17 is then adjusted so that the control wheel just touches the micrometer. When subsequently in operation the grinding wheel touches the control wheel the latter is moved axially to break the circuit controlling the cross-feed. In a modification the control wheel axis may be parallel to the grinding wheel axis, so that there is no axial control wheel movement, the control wheel rotation then being arranged to affect the required control. In this case a pin 40 in the control wheel is arranged on rotation of the wheel to operate a switch 42, Fig. 9, which may be reset by a lever 41. In another form the control wheel spindle is inclined, Fig. 6, and has a fine axial adjustment for setting purposes. The periphery of the wheel is of spherical form. In another modification the control wheel spindle carries an insulating collar with a metallic insert which engages a wiping contact forming part of an electric circuit when the control wheel is rotated. Any number of such collars may be employed. In another modification, Fig. 12, the control wheel may be operated by the tool 59 of a planing machine to control the operation thereof. Alternatively, the control wheel may be fed downwards with the tool and be arranged to engage a plane surface when the desired depth of cut is reached. Instead of operating a switch the control wheel may have radial lines printed in colours to give a visual indication to the operator when the control wheel is rotated. The micrometer may also be replaced by other measuring devices.