Patent ID: 8475229

Claim:
Grinding machine for grinding rod-shaped workpieces having a non-circular cross-section formed by at least one of straight and curved lines and flat end faces that run parallel to one another, comprising: a machine bed supporting a slide track on which are arranged on a common axis C two workpiece headstocks adjustably axially spaced from each other; wherein the workpiece headstocks comprise respective clamping jaws having respective clamping surfaces facing one another; and each workpiece headstock further comprises an electric motor for rotating a respective one of the clamping jaws about the C-axis; a control device configured to cause the two clamping jaws to rotate synchronously and in-phase and to clamp the workpiece by moving against the end faces of the workpiece; a grinding headstock arranged on the machine bed such that it can be moved in a controlled manner along an X axis perpendicular to the C axis; a first grinding wheels or wheel and a second grinding wheel carried by the grinding headstock, rotationally driven first and second grinding parallel spindles on which are respectively mounted the first grinding wheels or wheel and the second grinding wheel, the grinding wheels being arranged above one another such that the first grinding wheels or wheel is higher and closer to a perpendicular plane of symmetry of the slide track than the second grinding wheel; wherein the first grinding wheels or wheel defines a space laterally bounded by opposed walls surfaced with abrasive layers spaced apart by distances substantially equal to length of the workpiece for grinding the end faces of the workpiece; and wherein axial width of the second grinding is at least equal to length of the workpiece for grinding longitudinal sides of the workpiece; a holding device arranged between the workpiece headstocks, mounted for being rotationally driven about an axis parallel to axes of the spindles and carrying at least three angularly spaced pairs of grippers; wherein each pair of grippers is configured for clamping the workpiece on its longitudinal sides and for bringing it with a longitudinal axis thereof parallel to the C axis into a first machining position for grinding the end faces thereof concurrently by said opposed walls surfaced with said abrasive layers and for subsequently transferring the workpiece to a second machining position at which the workpiece is clamped by the clamping jaws; wherein the second grinding wheel is located in the second machining position and the control device is also configured to effect grinding of the longitudinal sides of the workpiece by controlling rotation of the workpiece about the C axis and movement of the second grinding wheel in a direction along the X axis.