| 摘要 |
PURPOSE:To enable automatic grinding under constant pressure, by engaging a driving gear fitted on the drive shaft of a motor, with a driven gear fitted on a rotary shaft, and by coupling the rotary shaft and the drive shaft to each other through a link, and providing a spring between the link and a case at the side of the drive shaft. CONSTITUTION:When a ground surface 24 has a projection 25, a grindstone 15 comes into contact with the projection so as to ascend to compress a spring 19. As a result, pushing torque Ts increases so that the rotation of the grindstone 15 is retarded. For that reason, a link 16 is turned counterclockwise so that the spring 19 is compressed further. Consequently, the grindstone 15 goes up from the ground surface 24 so that a pushing force Fp decreases. Because of the decrease in the pushing force Fp, the spring 19 acts to turn the link 16 clockwise to increase the pushing force. In other words, if the height of the projection 25 is large, the increase in the pushing torque Ts is absorbed by a differential mechanism including the link 16, so that the grindstone 15 comes into contact with the ground surface 24 under constant pressure, regardless of the height of the projection 25. |
