GB814086A - Improvements relating to machine tools - Google Patents

Abstract

814,086. Grinding. JONES & SHIPMAN Ltd., A. A., and HOULDSWORTH, J. Dec. 28,1955 [Dec. 14, 1954], No. 36159/54. Class 60. A machine tool has means for converting a relative rectilinear motion between the work and the tool into a rotary motion of the work including a rotatably-mounted body which is coupled in use to the work so as to rotate the latter, and a transmission tape which is wrapped in a plurality of side by side turns around this body with its length at an oblique angle to the axis of rotation of the body and is movable transversely to this axis, in response to said relative rectilinear motion, to wind helically on and/or off the body and thus rotate the latter and the work. A machine for grinding the helical teeth of milling culters comprises a work-carrying frame 4 pivotally adjustable on a worktable 3 running on a bed 1. The frame 4 is secured in adjusted position by a plate 5 co-operating with a segment 6. The frame 4 carries a plate 7 having an upstanding arm 8 carrying a cylindrical bearing 9 ; rotatable in annular bearing races in the cage is the hollow cylindrical end 10 of a spindle 11, this end being internally tapered to receive the part conical end g an arbor 13 carrying workpiece 14. The workpiece 14 may also be supported at its outer end through a mounting sleeve 15 from a centre 16 carried by a tailstock 17 on the frame 4. The grinding wheel 18 is mounted on a wheel head 19 capable of being orientated. The spindle 11 is rotatably supported at its other end in a bearing 20 carried by an arm 21 on an extension 22 of the frame 4. Mounted on spindle 11 between bearings 9, 20 is a drum 54 capable of rotation relative to spindle 11, both spindle 11 and drum 45 projecting through the bearing 20. A setting dial 23 adjustable relative to drum 45 by worm gearing has a ring of closely spaced apertures selectively engageable by a retractible pin 25 carried by a block 24 secured to the end of spindle 11. A steel tape 44 is wrapped in a number of side by side terms around the drum 45 ; the ends of the tape are attached to screwed rods 43 received in anchorage sleeves in lugs 42 at the diagonally opposite corners of a frame 41 upstanding from a cross slide 27 carried by the table 3 or by the frame 4. The cross slide carries a roller 31 co-operating with an adjustably inclined bar 32. One end of the bar 32 is articulated to an arm 35 by nut and bolt 39 adjustable along slot 40 in arm 35, the arm projecting from a bracket 34 adjustable along a groove 33 in the machine bed 1. The bar 32 is also supported by a stud 37 on an arm 36 carried by a bracket 38 adjustable along the groove 33. Thus as the table 3 is traversed longitudinally the work is given a conjugate rotation. The mid-point of the tape 44 may be secured to the drum 45 by a clamp 46. The drum 45 may be replaced by a larger drum 45<SP>1</SP>, and the ends of the tape are then secured to alternative anchorages 42<SP>1</SP> on the frame 41. Alternatively, the inclined bar 32 may be carried by the cross slide 27 and co-operate with a roller fixed on the machine bed. In another arrangement the cross slide may be directly propelled and thus used to impart the traversing movement to the worktable, e.g. by employing a roller 47 carried in a bracket 48 secured to the crossslide 27, the roller co-operating with an inclined bar 49 adjustably fixed to rails 2 attached to bed 1. The effective edge of the inclined bar 32 may be shaped to vary the form of each individual tooth along the length of the latter, whereby cutters having a non-parallel axial section can be ground with a constant helical angle.