Patent GB-1421850-A (GB)
Title: Sharpening apparatus
IPC: B24B3/56
Filed: 1973-04-25
Abstract: 1421850 Sharpening cutter blades LUIGI RIZZI & C SpA 25 April 1973 [12 May 1972] 19718/73 Heading B3D [Also in Division B4] An apparatus for sharpening a cutting blade 3 of a skin splitting machine or. the like, comprises a carriage 1 displaceable horizontally perpendicular to the edge of the blade and having two arms 15, 16 pivoted on horizontal axes 13, 14 parallel to the blades, the free end of each arm carrying a grinding wheel 23, 24, the diameters and positions of which are such as to form predetermined cutting angles on opposed surfaces of the edge of the blade, the arms being vertically displaceable and the upper arm being also horizontally displaceable to adjust the upper cutting angle relative to the lower. The carriage is slidable along guideways 1a on a base 2 which has a support 4 for plates 5 receiving the blade 3 in the form of a continuous strip running over a pair of pulleys, one of which is driven. The plates are adjustable by screws 6 rotatable by knobs 7 or automatically by gear- 9, 10 driven from a shaft 8 having a gear-wheel 8a rotatable by a pawl 8b of hydraulic means 8c. The carriage has a pair of supports 11, 12 having pivots 13, 14 for the arms 15, 16. The arm 15 is mounted on bearings 17, 18 on the pivot 13, the bearings being concentric with the pivot. The arm 16 is mounted on bearings 19, 20 on ends 14a, 14b of the pivot, the ends being eccentric to the pivot. End 14a has a graduated disc 29 secured thereto by a nut 30. An outer position of the end 14a is formed as a nut 14c whereby the pivot can be rotatably adjusted in the support 12 to a position indicated by a pointer 32 reading against the graduated disc 29: the adjustment has a horizontal component for moving the arm 16 and hence the grinding wheel 24 carried thereby horizontally with respect to the grinding wheel 23 carried by arm 15 to adjust the upper cutting angle relative to the lower. Each of the grinding wheels is driven by a belt 27, 28 from a motor 25, 26 mounted on its respective arm. Each arm is vertically adjustable about its pivot by rotation of a respective wheel 35, 41 either manually by means of a handle 36, 42 or automatically by a pawl 43, 44 moved by hydraulic devices 45, 46 each wheel being connected by a respective shaft 37 and gears 38 to a screw 39 supporting a roller 40 on its arm. In operation, the blade 3 is initially positioned by adjustment of the screws 7 and the carriage 1 is adjusted horizontally by a handwheel 34 and screw 33 so that the lower grinding wheel 23 will grind the lower bevel of the blade to, say, 8 degrees. Such position is indicated by a graduated rod 48 on the carriage reading against the edge of the blade. The position of the upper grinding wheel 24 relative to wheel 23 is adjusted by rotation of the pivot 14 to a position indicated by the graduated disc 29 to determine the angle of the upper bevel of the cutting edge. The sharpening of the blade may be controlled automatically by a magnetic detector (50, Fig. 10, not shown) which controls the hydraulic device 8c for rotating the shaft 8 to advance the blade 3 following wear, and the hydraulic devices 45, 46 which act through the screws 39 and rollers 40 to vertically displace the arms 15, 16 and move the grinding wheels to compensate for wear thereof.