| 摘要 |
908,840. Grinding fixtures. ERICKSON TOOL CO. Aug. 12, 1959 [May 20, 1959], No. 20890/60. Divided out of 908,839. Class 60. A fixture for grinding a spade drill blade which has both a cutting end constituted by at least one cutting edge having primary and secondary relief and extending generally radially of the axis of the blade and an anchoring end by which said blade is adapted to be held in a holder therefor, comprises a unitary block having a first face against which such blade can be clamped for grinding and clamping means on said block operative to clamp the blade against such face, said block having a second face which is inclined to the first face at an angle corresponding to the desired angle of secondary relief. The fixture is a solid block of metal having front and rear plane faces 42, 43, parallel and plane end faces 45, 46 and top and bottom plane faces 47, 48. Face 42 is perpendicular to face 48 and the faces 47, 48 are relatively inclined so that the angle between them in a plane perpendicular to the face 42 is equal to the desired angle of secondary relief, e.g. 14 degrees. The face 43 is inclined at an angle to the face 47 of 90 degrees plus the primary relief angle, e.g. 7 degrees. The angle between the faces 46, 47 is equal to 90 degrees plus the side relief angle. The top face 47 has a diagonally disposed groove 49 adjacent one end or the other of which is secured by screw 51 a block 50 having side and end faces that are perpendicular to each other and to the top face 47. Also mounted in the groove 49 is a longitudinally adjustable bracket 52 provided at one or both ends with an upstanding portion 53 having side and end faces that are perpendicular to each other and to the top face 47; the bracket 52 has a slot 54 and is held in adjusted position by a screw 56. The block 50 and portion 53 engage the locating faces of the blade 11. Two pairs of threaded holes 57, 58 in the top face 47 on opposite sides of the groove 49 accommodate a screw post 59 for a clamping member 60 having a screw 61 bearing on the top face 47 to force the free end 63 of the clamping member 60 down on the blade 11. The grinding of secondary relief, primary relief, side relief and top rake is described. |
