Apparatus for profile grinding closed curved surface

In a profile modeling grinding apparatus of the class wherein a worktable supporting a workpiece is profile controlled by the cooperation of a master cam formed with a profile on the periphery thereof corresponding to the closed curved surface to be ground and a master roller, and wherein means is provided for imparting a composite motion of rotation and translation required to perform a constant speed grinding operation to said worktable, the improvement which comprises a ram movable in the vertical direction with respect to the upper surface of said worktable, an intermediate post supported by said ram to be movable in the direction of the primary feed which is applied to a grinding wheel in the horizontal direction, a vertical supporting shaft, means for supporting the opposite ends of said supporting shaft by said intermediate post, a grinder head supported by said supporting shaft to be swingable thereabout in a plane parallel with the upper surface of said worktable, a grinder shaft extending through said grinder head in parallel with said supporting shaft, said grinding wheel being secured to said grinder shaft, a correction shaft supported by said grinder head, a pair of guide coupling members cooperating with the opposite ends of said correction shaft so as to drive said ends and with fixed shafts rotatably supported by said ram so as to cause said fixed shafts to act as the drive members for said guide coupling members, a correction cam provided with a correction profile on the outer periphery thereof and secured to said worktable and said master cam to rotate therewith, a press roller, means for normally urging said press roller against said correction profile of the correction cam, means for transmitting the angular movement of said press roller to said guide coupling members so as to impart thereto corresponding angular movement, and means for applying a predetermined primary feed to said grinding wheel, whereby when a grinding wheel having a diameter different from a predetermined standard diameter is used, the position of said grinder shaft is corrected in accordance with the angular position of said worktable thus grinding a closed curved surface in said workpiece.