Abstract: A process and apparatus for centering accurately and speedy a workpiece on a magnet chuck mounted on a work spindle. A pair of action pads spaced away from one another comes into engagement with the workpiece attracted to the work spindle, thereby performing the centering operation. The action pads are mounted on a support plate that can freely turn on a fulcrum. As the fulcrum makes head towards a rotational center of the magnet chuck, the action pads comes into abutment in a rocking manner against the workpiece that is held at off-center relation in the chuck, thereby compensating the off-center relation to keep a center of the workpiece in alignment with the rotational center of the chuck.

Abstract: The thickness of a crossed roller bearing is reduced and attachment of a lid member 17 to a loading hole 16 from which rollers 15 are loaded is facilitated. Raceway grooves 13, 14 are respectively formed in an inner ring 11 and an outer ring 12. The rollers are loaded from the loading hole formed in the outer ring, and interposed between the raceway grooves. The axes of the adjacent rollers lie at right angles to each other. The loading hole is covered by the lid member. A flange 22 is provided on an outer periphery of the outer ring, and has an outer end face 22a that is approximately flush with an end face of the outer ring and an inner end face 22b that is either in a position in alignment with or in an inner position across outer ends of the raceway grooves in an axial direction.

Abstract: A process and apparatus for centering accurately and speedy a workpiece on a magnet chuck mounted on a work spindle. A pair of action pads spaced away from one another comes into engagement with the workpiece attracted to the work spindle, thereby performing the centering operation. The action pads are mounted on a support plate that can freely turn on a fulcrum. As the fulcrum makes head towards a rotational center of the magnet chuck, the action pads comes into abutment in a rocking manner against the workpiece that is held at off-center relation in the chuck, thereby compensating the off-center relation to keep a center of the workpiece in alignment with the rotational center of the chuck.

Abstract: The present invention provides a ball spline which enables the manufacturing of an outer cylinder to be done simply, the manufacturing cost to be reduced, and the loading of balls to be done easily. This ball spline comprises a slider fitted around a ball spline shaft so that the slider can be slid freely thereon, and so that rotational torque can be transmitted to the slider. In the slider, a retainer unit fitted in the outer cylinder is divided into two at the regions of direction changing passages, and rings provided with curved portions constituting guides for balls are fitted in the portions of the outer cylinder which are opposed to the regions of the direction changing passages. The rings are fitted between the outer cylinder and retainers.