Patent GB-1325650-A (GB)
Title: Machine tool
IPC: B24B27/00
Filed: 1972-06-27
Abstract: 1325650 Grinding; milling R HABIB 27 June 1972 [30 June 1971 15 June 1972] 30144/72 Headings B3D and B3K A machine for grinding or milling a workpiece 8, such as a spiral milling cutter and having a substantially hemispherical head 107 comprises a generally horizontal carriage 4, 5, an orientable grinding or milling wheel carrier 3, means for setting the position of the carriage relative to the carrier in a generally horizontal plane, a support 6 mounted on the carriage for rotation and inclination, respectively, about a vertical axis 25 and a horizontal axis 113, a headstock 7 including a rotable spindle 51 adapted to support a workpiece 8, the headstock being slidably mounted on the support along a direction parallel to the axis of the spindle, the axis of the spindle being adapted to intersect the vertical axis, the intersecting axes defining a plane perpendicular to the horizontal axis, and a device mounted on the support for helicoidally driving the headstock spindle. As described, the carrier 3 clamps the spindle 14 of a grinding wheel 15 which is driven by a belt from a motor mounted on a plate 16. The carrier is adjustable about a horizontal pivot 13 extending from a plate 12 on a bearing 11 slidably mounted on a sleeve 10 rotatably mounted in a vertical spindle 9 of a column 2 on a base 1. A carriage slide 4 is movable by a crank 21 along a dovetail 20 and carries a transverse slide 5 movable by a crank 34 and screw 33 having an end 35 releasably connected to the slide 5 by a clamp 36. A horizontal plate 23 is secured to slide 5 and has bearings for a vertical shaft 25 acting as a pivot for a carriage section 24 having a horizontal pivot 113 for a section 112 which can be locked in an inclined position by means, not shown. The section 112 supports a slide 6 and has an extension 37 provided with a pivot 39 for an arm 40 which is adjustable about the pivot to an angular position determined by the helix 106 of the tool to be ground. The arm has a pair of guide rods 43, 44 for a cursor 45 secured to a belt 52 guided over pulleys 53, 54 on the arm and driven by a motor 55. The cursor 45 has a projection 57 carrying a roller 70 which engages a groove 71 in the under side of a hollow arm 46 fixed to a plate 47 secured to slide 6 and carrying the headstock 7 of the sprindle 51 for the workpiece 8. The projection 57 on cursor 45 is secured to a belt 58 entrained about rollers 59, 60 in the hollow arm, roller 59 being connected by belt drives 64, 67 to a pulley 68 on the spindle 51. When the arm 40 is secured in a predetermined angular position, movement of the cursor by the motor 55 causes movement of the slide 6, and hence axial movement of the tool 8, by engagement of the roller 70 with the groove 71, and rotation of the tool by way of the projection 57 and belt drives 58, 64, 67. The slide 6 is adjusted about the horizontal pivot 113 to the helix angle of the tool. To grind the hemispherical end 107 of the tool, the slide 6 is adjusted so that the centre 108 of the end is on the axis of pivot 25. Grinding is started at the end (115, Fig. 5, not shown) of the tool, the slide 6 being rotated through 90 degrees to the position shown in Fig. 1 and then the motor 55 is actuated to move the cursor. The machine also includes a backing-off device 73 which, when belt 67 is removed, is connected to pulley 68 of the headstock by a belt 77, Fig. 4. The belt runs over a pulley 76 connected to a cam 75 bearing against a lever 78 having a finger 80 abutting a further lever 81 movable about a pivot 82. The lever engages an adjustable pin 91 on a block 89 carried by a pivoted member 85 abuting an adjustable screw 92 on an arm 94 adjustably mounted on a bracket 95 fixed to the guide 22 for slide 5. The member 85 is pivoted to a support 74 mounting the device 73 in the slide 6 so that as the cam 75 rotates, the slide 5 is reciprocated to move the tool towards and away from the grinding wheel. To grind a profiled cutter 103, a cam 102 may be secured to slide 6 and engaged by a follower 101 which is positioned vertically beneath the operative points of the grinding wheel 15 in a post 98. The slide 6 is freed so as to be rotatable about pivot 25 and the slides 4 and 5 are also freed from sliding movement so that an operator can move the slides and press the cam against the follower.