Abstract: A grinding machine wherein a column supports a vertically movable holder for the spindle of a grinding wheel and the dressing apparatus is mounted on the holder. The dressing apparatus has a carriage disposed at a level above the grinding wheel and movable up and down radially of the grinding wheel. The carriage has a forward extension for a follower which supports a pivotable carrier for two parallel or nearly parallel spindles each of which carries one or more dressing tools. The carrier is pivotable relative to the follower between a first position in which the first dressing tool is ready to treat the working surface of the grinding wheel and a second position in which the second dressing tool is ready to treat the working surface. Separate motors are provided to move the follower along the carriage, to move the carriage along the holder, to drive the spindles for the dressing tools, as well as to pivot the carrier relative to the follower.

Abstract: Apparatus for supporting, locating and transferring plate-like or disc-shaped workpieces between several stations or between several machines where each of two plane parallel surfaces of each workpiece is subjected to one or more treatments has at least two partially overlapping plate chucks. A workpiece which is introduced by one chuck into the space where the two chucks overlap is released by the one chuck and is then attracted by the other chuck so that the previously exposed surface of the workpiece becomes concealed and vice versa. The chucks can transport workpieces between successive stations of a series of stations where the surfaces of the workpieces can be subjected to a coarse and thereupon to a precision or final treatment such as grinding and polishing, lapping or honing. If the chucks are installed in a separate frame, they can be rotated through 180.degree. about an axis which is parallel to their work-contacting surfaces so that a workpiece between such chucks is inverted, i.e.

Abstract: A grinding machine wherein the grinding wheel has a profile consisting of recurrent identical sections, as considered in the axial direction of the grinding wheel. The profile of the grinding wheel is treated by a dressing tool whose profile is that of a worm and is complementary to the profile of the grinding wheel. The axial length of the dressing tool equals that of one section of the profile of the grinding wheel and the axes of the grinding wheel and dressing tool make an angle which matches the lead angle of the worm-like profile of the tool. A feed screw is used to move the dressing tool in parallelism with the axis of the grinding wheel at a rate such that axial displacement of the tool per revolution of its shaft equals the axial length of one section of the profile of the grinding wheel. The grinding wheel is used to convert blanks into toothed racks.

Abstract: Apparatus for supporting, locating and transferring plate-like or disc-shaped workpieces between several stations or between several machines where each of two plane parallel surfaces of each workpiece is subjected to one or more treatments has at least two partially overlapping plate chucks. A workpiece which is introduced by one chuck into the space where the two chucks overlap is released by the one chuck and is then attracted by the other chuck so that the previously exposed surface of the workpiece becomes concealed and vice versa. The chucks can transport workpieces between successive stations of a series of stations where the surfaces of the workpieces can be subjected to a coarse and thereupon to a precision or final treatment such as grinding and polishing, lapping or honing. If the chucks are installed in a separate frame, they can be rotated through 180.degree. about an axis which is parallel to their work-contacting surfaces so that a workpiece between such chucks is inverted, i.

Abstract: A surface grinding machine wherein a tool holder is mounted on an upright feed screw which is in mesh with a rotary spindle nut. The latter is held against axial movement in the column of the grinding machine and is normally driven by a torque transmitting unit having an endless toothed belt trained over a first pulley which is coaxial with the nut and a second pulley mounted on the output shaft of an electric motor. A gear train is installed in parallel with the torque transmitting unit to prevent automatic lowering of the tool holder when the belt breaks. The gear train has a first gear coaxial with the first pulley, a second gear coaxial with the second pulley and an additional gear meshing with the first and second gears. The tension of the belt is monitored by a detector which transmits a signal when the belt breaks, and such signal is used to immediately arrest the motor.

Abstract: A double head grinding machine for the roots of turbine blades or similar complex workpieces with concave and/or convex surfaces has two parallel horizontal spindles the upper of which carries a single grinding wheel and the lower of which carries two coaxial grinding wheels. The base of the machine frame supports a table which is movable by a first motor in a direction at right angles to the axes of the spindles, tangentially of the grinding wheels and along a horizontal path below the spindles. A work holder on the table is movable by a second motor along a sloping path in a direction making an angle of 30 degrees with the axes of the spindles and at right angles to the direction of movement of the table in such a way that the workpiece which is held in the holder can be moved toward or away from the grinding wheels.

Abstract: A grinding machine with two parallel horizontal spindles which are movable radially of toward and away from each other and wherein each spindle carries a set of several coaxial grinding wheels having different outer diameters. The smaller wheels are nearer to and the larger wheels are more distant from the outer end portions of the respective spindles which are mounted, in cantilever fashion, in vertically movable carriers guided by vertical ways at the front side of an upright column forming part of the machine frame. The dressing mechanism for the grinding wheels has discrete coaxial or angularly staggered dressing discs for the respective grinding wheels, a common dressing disc for the grinding wheels on each spindle, or a single dressing disc for all of the grinding wheels.