Patent GB-978978-A (GB)
Title: Form relief grinding fixture for milling cutters, twist drills and similar cutting tools
IPC: B24B3/02
Filed: 1963-07-20
Abstract: 978,978. Grinding. W. B. SKIPPER. July 20, 1963, No. 28818/63. Heading B3D. Apparatus for grinding relief on tools, such as drills, milling cutters and the like, comprises a work-holding spindle 26 rotatably mounted in a headstock 21 carried by a bar 7 rotatable about its axis in a base 3, a second spindle 30 connected to the work spindle through a gear train 27, 28 and two elements 31, 33 of a differential, a peripheral cam 39 mounted on the second spindle, and a lever 14 pivoted on the headstock and coacting with the cam to rock the headstock upon rotation of the second spindle. The rocking of the headstock is effective about the bar to grind a radial relief on the tool, the cam also having a surface 40 acting on a further lever 42 to move the headstock axially for grinding an axial relief on the tool. The bar 7 is mounted in bearings in base flanges 1, 2 so as to be rotatably and axially movable and carries the headstock 21 which is of inverted L-shape having a vertical portion 19 and a bifurcated upper portion 20, 21. The workholding spindle 26 is rotatably mounted in bearings 25 in the upper end of the portion 19 and carries a gear 27 connected by gearing, not shown, to the gear 28 on the spindle 30 which is rotatably mounted in the portion 20. The right-hand end of the spindle 30 carries a planet carrier 31 having gears 32 meshing with a gear 33 joined to the gear 28 and a gear 34 on a spindle 35 normally held against rotation in the portion 21. The left-hand end of the spindle carries a gear 65 engaging a gear 64 mounted on a spindle 62 which is carried by a plate 60 having a handle 61 and carries a further gear 63 meshing with a gear 59 secured to the portion 20 of the headstock. The plate 60 is secured to a sleeve 38 which is rotatable in the portion 20 and carries the cam having a peripheral surface 39 and a radial surface 40. Cam surface 39 engages a follower 16 on the end of a lever 14 which is pivoted at 9 to the headstock portion 20 and has an adjustable projection engaging a plate 10 secured to an arm 8 extending from the base flange 3. The cam surface 40 engages a follower 41 on the upper end of a lever 42 which bears against an adjustable fulcrum 57 on a rib 56 on a back plate 43 rigidly secured to the headstock, the lever 42 also having a slot 45 engaged by a pin 44 on the backplate. A pressure pad 46 at the lower end of the lever engages a rod 47 which is slidable in a housing 48 and abuts a lever 50, 51 mounted on a pivot 49 on the back plate and joined by a bolt 53 to the arm 8, the rod normally being prevented from sliding by a screw 55. When the plate 60 is rotated by means of the handle 61, the cam is rotated so that the surfaces 39 and 40 cause radial and axial movement of the headstock, and the spindle 30 is rotated to rotate, by way of the gears 27, 28, the work-spindle 26; a reverse gearing between the gears 27, 28 may be operated for the grinding of left-hand relief, and the screw 55 released to permit axial movement of the rod 47 and a nut 54 tightened against the arm 8 so that rocking of the lever moves the pivot 49 to offset axial movement of the headstock in the reverse direction. The gear-wheel 34 may be released from its locked position and driven at a predetermined speed relative to the traverse of the work-table of the grinding machine for the relief grinding of helical cutters. The gear 28 may be driven by a gear 15 driven in relation to the work-table travel for relief grinding taps. The bearing 3 is adjustable about a vertical axis on the base flange, and the bearing 4 is adjustable transversely of the base flange 2.