Patent GB-408673-A (GB)
Title: A new or improved crank-shaft or like grinding tool
IPC: B24B5/42
Filed: 1932-10-14
Abstract: 408,673. Grinding crankshafts. BROWN, W., 20, Abbey Street, Rugby. Oct. 14, 1932, No. 28693. [Class 60.] Disc, wheel, and roller apparatus ; gauges; spindles and spindle mountings ; trueing rotating tools.-In a tool for grinding crank-shafts and the like a driving-shaft carrying a grinding- wheel has its axis at right angles to the shaft to be ground and is mounted in a guide member which rotatably receives the shaft to be ground. A U-shaped frame 2 is secured to a slot in a guide member 1 which is integral with a tube 3 threaded to receive a threaded sleeve 4 carrying an inner tube 5, one end of which passes into the member 1. A driving shaft 8 carrying a grinding-wheel 9 is mounted in bushes and ball-bearings 6 and the outer end of the drive shaft is squared for engagement with the armature shaft 10 of an electric motor 11. The grinding-wheel is secured against a flange 9<a> by a central screw and a spring washer 12 tends to press the grinding-wheel towards the work. In order to feed the grinding-wheel axially, a sleeve 13 fixed to the sleeve 4 and to the motor casing is rotated, thus screwing the sleeve 4 over the guide tube 3, and moving the tube 5 and the grinding spindle, in an axial direction. A micrometer adjustment is obtained through graduations 14 on the sleeve coacting with a mark on the guide tube 3. An adjustable division mark on the sleeve may be arranged to register with the mark on the tube 3 when the work is to size so that successive crank pins may be finished to the same diameter. A friction brake device 21 is provided to prevent accidental movement of the feed tube 5. The work a to be ground, is positioned within the U-shaped frame 2 by means of hardened bearing plates 22, 23 mounted in adjacent limbs of the frame and a movable bearing consisting of a triangular block 26 mounted on a strip of spring steel 24 adjusted to work of different diameters by a screw 27. The frame 2 may be adjusted laterally on guide 1 by a screw 29 and nut 28, thus allowing the desired portion of the grinding disc to be brought against the work. The bearing 22 may be ground parallel to the grinding-wheel by using a grinding spindle of sufficient length to reach the member 22. In order to withdraw the grinding-wheel from the work against the pressure of the spring 12 without disturbing the feed adjustment a disc 31 has opposed raised cam portions coacting with similar cams on the end of the sleeve 4, and has also notches engaged by pins on a sleeve 35 rotatable on the sleeve 13. Thus, when the sleeve 35 is rotated, the cams are caused to ride over each other and the member 31 moves axially of the sleeve 4 carrying with it the outer bearing 6 and the grinding-spindle. The motor 11 carries a tubular handle 37 receiving a plug 38 carrying the current and also forming a rotary switch. The tubes 13 and 37 form handles for supporting the tool as it follows the motion of a crank pin in operation. In order to turn the periphery or true the face of the grinding wheel, a bracket fitted with a diamond tool may be fitted in place of the plate 23. For facing, the diamond may be traversed by rotation of the nut 28 while for edge turning the grinding wheel is moved longitudinally past the tool which is adjusted for depth of cut by the nut 28. In some cases the grinding wheel may be traversed laterally to and fro during operation by automatic operation of the nut 28. In another modification, Fig. 5, for operating on the main journals of a shaft, the tool sleeve 39 is fitted with ball bearings for the grinding spindle which has a squared driving end 41. A sleeve 43 may receive the sleeve 13 of a motor casing and bracket 44 may serve to secure the tool adjustably to a plate 46 having a stem 47 adapted to be secured to a lathe tool-post. In either form, a jet of water may be directed on to the grinding wheel during operation.