A workpiece change for use in a machine tool that comprises a tool spindle for clamping tools for machining workpieces, comprises two wheels arranged parallel to one another and rotatable about an axis of rotation into at least two prominent angular positions. Two swivel tables for clamping workpieces are arranged between the wheels and are each mounted on the wheels to swivel about a swivel axis which runs parallel to the axis of rotation. In each prominent angular position, one of the swivel tables is located in its working position in which clamped workpieces can be machined with the tools. Both wheels are supported at their rim.

A workpiece change for use in a machine tool that comprises a tool spindle for clamping tools for machining workpieces, comprises two wheels arranged parallel to one another and rotatable about an axis of rotation into at least two prominent angular positions. Two swivel tables for clamping workpieces are arranged between the wheels and are each mounted on the wheels to swivel about a swivel axis which runs parallel to the axis of rotation. In each prominent angular position, one of the swivel tables is located in its working position in which clamped workpieces can be machined with the tools. Both wheels are supported at their rim.

A multi-tool positioning and manufacturing system moves a workpiece among many tools, such as grinding wheels, each of which performs a manufacturing operation on the workpiece. The system moves the workpiece automatically, quickly, repeatably, and precisely among the tools, without any manual intervention. It can perform the same manufacturing operations as many separate tools, such as grinding the inner diameter, outer diameter, and rib of a tapered roller bearing cone. Because a machinist does not have to move the workpiece between machines for different operations, the total manufacturing process can be faster and higher yield than with separate tools. The system can also move a single dresser among the tools for dressing and truing, further increasing manufacturing efficiency by eliminating the need for separate dressers for separate tools.

A positioning apparatus including a base structure; a first workpiece support; a second workpiece support; a support member supporting the first workpiece support and the second workpiece support; and a drive arrangement arranged to drive the support member relative to the base structure from a first position, where the first workpiece support is positioned on a processing side of the base structure and the second workpiece support is positioned on an opposite loading side of the base structure, to a second position, where the first workpiece support is positioned on the loading side and the second workpiece support is positioned on the processing side; wherein the drive arrangement is arranged to drive the first workpiece support along a first path and the second workpiece support along a second path when driving the support member from the first position to the second position, the first and second paths being non-circular.