A machine tool including a movable spindlehead member having an extensible and retractable tool spindle member, and a work-supporting compound slide assembly having two slide members movable in directions at right angles to one another. All members can be selectively "inched" and moved at feed and transverse rates in opposite directions along their respective paths of movement by two variable speed motors, one connectable to the spindlehead or the tool spindle and the other to either of the two slide members of the work-supporting compound slide. The motors are connected to their respective tool and work-moving members through discrete transmissions of the continuously meshed gear type under the control of hydraulically-actuated clutches. Spindle feed is alternatively provided from a spindle drive motor to correlate feed with rotation. Brake discs selectively deflectable against fixed abutments and connected to rotatable parts will maintain selected tool and work-carrying members in fixed positions.
Adjustable machining apparatus for machining a cylindrical workpiece, such as an electrical generator rotor or stator. The apparatus includes a spindle for holding a cutting tool, which spindle in turn is engaged by a motor for rotating the spindle and cutting tool. Attached to the spindle is a swivel for pivoting the spindle about a pivot point laying on a first axis parallel to the longitudinal axis of the workpiece. A first translation mechanism is attached to the swivel for moving the swivel along a second axis perpendicular to the first axis. A second translation mechanism is connected to the first translation mechanism for moving the first translation mechanism along a third axis transverse to the longitudinal axis of the workpiece. A third translation mechanism is connected to the second translation mechanism for moving the second translation mechanism along a fourth axis paralle to the longitudinal axis of the workpiece. The apparatus is removably attachable to the workpiece, such as by electromagnets. Thus, the apparatus is removably attachable to the workpiece and operable to provide four degrees of freedom of movement to the cutting tool.
A method and apparatus for controlling the rotational speed of an electronically controlled power tool in both the forward and reverse direction. When the reversing switch is placed in the reverse direction, the electronic speed control circuit automatically limits the speed of the motor to a predetermined maximum value. The speed control circuit also is adapted to sense a change in the state of the reversing switch and remove power to the motor until it coasts down to a relatively slow speed or to zero before reapplying power in the opposite direction. The speed control circuit monitors the rotational speed of the motor by means of a tachogenerator comprising a ring magnet mounted on the rearward end of the rotor shaft of the motor outboard of the commutator-end bearings and a Hall effect device mounted to the peripheral flange of a carrier which encircles the ring magnet so that the ring magnet and Hall effect device are separated by a small radially extending gap.
A brushless direct current motor includes a permanent magnet mounted to a rotor and a set of commutated stator windings. The motor further includes a circuit for changeably connecting the set of stator windings to operate in a first electrical configuration or a second electrical configuration and a circuit for commutating the set of stator windings when connected in the first electrical configuration or the second electrical configuration.
A brushless direct current motor includes a permanent magnet rotor and a set of stator windings. The motor further includes a circuit for changeably connecting the set of stator windings to operate in a first electrical configuration or a second electrical configuration. In the second electrical configuration, the circuit connects only some of the stator windings for receiving current. The circuit electrically isolates the unused stator windings from the used or connected stator windings.
