Patent GB-727607-A (GB)
Title: Improvements in and relating to grinding machines for scraper blades
IPC: B24B9/00
Filed: 1952-10-17
Abstract: 727,607. Grinding scraper blades. SCHWENSEN, S. V. GRUM-. Oct. 17, 1952, No. 26063/52. Class 60. A grinding-machine for scraper blades 1, Fig. 5, has at least one grinding tool 8 for grinding the edge surface of a scraper blade and at least two side face grinding members 6 adapted to be pressed simultaneously against the side faces of the blade 1, provision being made for each blade in a single setting-up to be several times in succession ground alternately by means of the grinding tool on its edge surface and by means of the grinding members on its side faces. The blades 1 are held in clamps 30 connected by ball joints 28 with a carrier 27 supported by a spindle 24 provided with an axial slot to receive a driving member such as a screw connected to a spindle 21. The latter is rotated by a wheel 26 and has a carrier 32 on which a member 34 is mounted by means of pivoted links for oscillatory movement in an arcuate path. This movement is produced by an eccentric pin 38 which is secured to a fixed shaft 18 and engages a slot 39 in the member 34. The edge surfaces of the blades are held by a spring 31 in contact with the flat face of the rotating abrasive disc 8 and in consequence of the rotation of the spindle 24 are lifted periodically from this face by a cam 40 and roller 41 so that the side faces of the blades are ground by the abrasive members 6 which are spring- loaded and mounted on the oscillating member 34. The blades are preferably lifted when they are radial to the disc 8 which may be oscillated about an axis parallel to its rotational axis to equalize wear. Several pairs of blades each actuated by the mechanism shown may be simultaneously treated on a single disc. In a second embodiment, Fig. 8, the blades are clamped in carriers 44 connected by shafts 48 to cranks or eccentrics 53 for opposed reciprocation axially of abrasive rollers 3. The carriers are periodically swung about the axis of a driving shaft 54 by cams 64 to bring their edge surfaces into operative relationship with abrasive members 6. The cams may be rendered inoperative by actuation of a draw-rod 82 which displaces the follower members 77. The shaft 54 rotates the members 3 and the cams 64 through toothed gearing, the speed of the cams being slightly different from that of the grinding members. A modification of the machine of Fig. 8 for treating a single blade is described in which the blade is periodically lifted by oscillation of the shaft 48 about its own axis and the shaft 54 operates a pump to supply a slurry of carborundum in oil to the abrasive member 3. The pump partially balances the inertia forces on the blade carrier. Fig. 10 shows a third embodiment for treating both edges of the blade 1 simultaneously. The blade is placed between stops 90 on a carrier 44 reciprocated on a guide 86 by a worm-driven crank from a shaft 91 which also drives through toothed gears 92, 93 and 97, two abrasive rollers 3. The latter are carried by links 95 which are pivotally mounted on the shafts 91, 94 of the gears 92, 93 and connected by a spring-loaded toggle mechanism 98, 99 tending to move the rollers 3 into contact with the edges of the blade. This movement is prevented by a spring-loaded lever 121 until a lid 89 to the machine casing 87 is closed to depress a push-rod 116 which moves the lever 121 to the left to release the toggle mechanism. To ensure symmetrical motion of the rollers 3 the central pivot 101 of the toggle mechanism is guided in a vertical slot. The side faces of the blade are treated by abrasive members 6 mounted on spring-loaded and hingedly-connected parts 104, 105 which are provided with rollers 107, 109 for engagement with a fixed abutment 108 and a spring-loaded abutment 110 whereby the members 6 are also brought into engagement with the blade as the lid 89 is closed.