Abstract: A system for detecting a limit of acceptable rotation for a joint is disclosed. The system includes a support that supports the joint and keeps its pivot point substantially stationary with respect thereto. The system also includes an extensible leg connected to the joint. A contoured member is mounted adjacent the extensible leg and has a surface shaped as a portion of a sphere. The contoured member is located so the pivot point of the joint substantially coincides with the center of the sphere and the periphery of the contoured member corresponds to the limit of acceptable rotation for the joint. Thus, as the leg pivots, the contoured member also moves a similar amount. A detector is used to detect the periphery of the contoured member surface and to assist in preventing further rotation of the joint in that direction.

Abstract: A high speed machine tool spindle assembly for firmly retaining a cutting tool therein, notwithstanding machine tool vibration, includes a spindle having an axially extending bore therethrough. Integrated to each end of the spindle is a tool gripping collet, each collet being urged radially inward against the shank of a cutting tool disposed in the spindle bore by a respective one of a pair of collet nuts which each threadedly engage the spindle adjacent to a separate one of collets at each spindle end. Each of a pair of collet nut drivers is carried by the spindle adjacent to a separate one of the pair of collet nuts and each is slidable along the axis spindle to jointly engage a separate one of the pair of collet nuts and the spindle.

Abstract: A machining center for machining the interior of an elongate tubular workpiece includes a bed on which a rotatably indexable member is slidably mounted for movement on the bed along a first axis. Removably fastened on the indexable member in spaced parallelism are a first and second hollow bore spindles each engaging the exterior surface of a tubular workpiece whose interior is to be machined. The first spindle is rotatably driven to rotate the tubular workpiece about its axis responsive to machine tool control system commands slidably mounted on the bed for movement thereon along a path perpendicular to the path of member movement in an upright. Extending from the upright parallel to the axis of upright movement for insertion into the workpiece bore is an arm which is movable along the upright along a vertical direction. At the distal end of the arm is a right angle, high speed rotary driven cutting tool carrying spindle.