Patent GB-834016-A (GB)
Title: Improvements in or relating to a machine tool
IPC: B24B47/04
Filed: 1956-07-04
Abstract: 834,016. Grinding. DECKEL, H., and DECKEL, F. W. July 4, 1956 [July 12, 1955], No. 20686/56. Class 60. A machine tool for grinding cylindrical and tapering bores comprises a longitudinallymovable rotating spindle carrying a guide member having a slideway perpendicular to the axis of the spindle, a displaceable slide mounted in the slideway and carrying a grinding means, an angularly displaceable cam member mounted co-axially in relation to said spindle and engaging said slide to determine the eccentricity of the grinding means in relation to the spindle, the cam member being non-rotatably connected to a push rod, having a coarsely threaded portion engaging in a like threaded portion in the spindle the vertical position of the push rod in the spindle. being controlled by a cranked lever, which moves vertically with the spindle and has one arm which contacts the edge of a master cam which does not move vertically with the main spindle. A grinding wheel 36 is carried by a slide 11 mounted for transverse movement on a block 10 on the end of a sleeve 9 ; the grinding wheel is driven by an electric motor carried by the slide 11. The sleeve 9 is rotatably held within an outer sleeve 4 and is rotated through gears 12, 13, splined shaft 14, bevel gears 15, 16 and gears 17, 18 from a shaft 19 driven by the prime mover of the machine. The outer sleeve 4 is non-rotatable but is movable axially, having a helically cut rack 5 meshing with a gear 6 meshing with a helical gear 8 on a shaft 3. The sleeve 4 is disposed inside a head 2 which can be tilted about the axis of the shaft 3 and clamped at any desired angle ; the shaft 3 is disposed within a casing 1b supported by a saddle 1a horizontally slidable on the top of the pedestal 1 of the machine. The pedestal 1 also carries a table 1c which is vertically and horizontally adjustable. The position of the slide 11 transversely of the block 10 is determined by a cam 20, a roller 21 on the slide being kept in contact with the cam by a spring 38. The cam 20 is integral with a bushing 22 rotatably mounted within the inner sleeve 9 ; the bore of the bushing 22 is engaged by the splined end 23 of a spindle 24a having a coarse-pitch thread 24 engaging a nut 25 rigidly held inside the sleeve 9. A grooved flange 26 at the upper end of the spindle 24a is engaged by pins 28 on one end of a cranked lever 27 fulcrumed on a pin 29 on the sleeve 4, the other end of the lever carrying a roller -30 co-operating with the edge of a master cam 31. Contact between roller 30 and master cam 31 is maintained by a spring 50 round the spindle 24a. The master cam 31 is adjustably mounted on a plate 32 carried by a shift bar 35 having a rack 34 engaged by a pinion 33. Movement of the shift bar 35 thus causes the shaft 24a to move axially relative to the sleeve 9 and the consequent rotation of the shaft 24a is imparted to the cam 20 so that the grinding wheel 36 is set at the desired eccentricity. For grinding cylindrical holes, a cylindrical grinding wheel is used, and the master cam 31 is set vertically, so that the eccentricity of the grinding wheel remains constant throughout its traverse. For grinding tapered holes, a tapered grinding wheel is used, and the master cam 31 is set at an angle, so that the eccentricity of the grinding wheel varies as the sleeve 4 moves axially. The contour of cam 20 is preferably an Archimedean spiral; alternatively it may be an eccentric, sine correction being provided by the cam face of the master cam 31.