Abstract: A machine tool is provided in which a carriage is supported on the upper flat surface of a work table by first bearings. The carriage extends beyond the bearings in one direction to support a tool, so that the weight of the carriage and tool creates a moment tending to rotate the carriage downwardly toward the work table on one side of the bearings. This is countered by a second bearing that extends to a second downwardly facing surface which may be a separate element or the undersurface of the work table. The second surface is adjustable for parallelism with the work table. Linear actuators move the carriage over the work table. In a multispindle machine, three actuators are required, at least two of which are nonparallel.

Abstract: Longitudinal position of the end of a drill bit (21) is determined in order to accurately control depth of a hole to be drilled. A drill bit (21) is rotated at a predetermined speed and caused to penetrate a light beam of known vertical position. The light beam, which is generated by a light emitting diode (50) and received by a photo transistor (54), is modulated by the flutes at the tip of the rotating bit to cause the photo transistor to provide an output signal that is modulated at a frequency that is a fixed multiple of the speed of the rotating bit. An operational amplifier (74) having a feedback circuit (80) that is resonant at the frequency of the modulated electrical signal from the photo transistor receives the photo transistor output signal as its input. The amplifier output experiences a sharp increase in magnitude upon receipt of the input signal at the resonant frequency of its feedback circuit.

Abstract: Positions of the spindles (116-124) of a multi-axis drilling machine (130,132,140,142) are precisely measured by three scanning laser beams (165,167,169). The scanning laser beams are swept in oscillating sweeps across areas of motion of each of three corner reflectors (160,162,164) that are fixedly mounted to an unguided spindle carrying structural beam (132) that is driven by three screw actuators (150,152,154). Each scanning laser beam is projected from a fixed reference position and tracks one of the corner reflectors. Each beam locks onto its associated corner reflector, and, while locked on, an interferometer (180,190,198) measures incremental changes of the distance between each scanning mirror (166,168,170) and its corner reflector.

Abstract: A tool changer is provided in which a rotary tray positioned beneath the forward edge of a machine tool supports a large number of tools in individual cartridges. A tool changer head includes two outwardly projecting tubular members and can be rotated about a horizontal axis, moved vertically and pivoted about a vertical axis. A vacuum or positive pressure can be generated in the tubular members. Therefore, the tubular members can be positioned over a tool in one of the cartridges after which the tool changer head is raised and rotated to extend the tool into the spindle of a machine tool which has been run past the forward edge of the machine. Negative pressure will withdraw the tool from the cartridge and positive pressure will drive the tool into the spindle. Similarly, a tool can be removed from the spindle by negative pressure and reinserted into the cartridge by positive pressure.

Abstract: An arrangement for providing universal movement of a machine tool is provided in which there are parallelogram linkages, one of which has a link which maintains parallelism with a worktable and is movable in any direction in a plane. A machine tool is carried by this link to perform an operation on a workpiece on the worktable. Two linear actuators converge from pivotal mountings on the worktable to the link. Selective extension and retraction of the actuators causes appropriate planar movement of the machine tool. A limit switch arrangement is provided by marking the movement of a portion of the mechanism on a plate as the mechanism is extended to its limits, cutting out the plate along the line marked, and positioning the actuating arm of a limit switch in the opening. Movement to the limits of the mechanism's travel will trip the switch and interrupt power to the actuators.

Abstract: A high speed spindle is provided which includes a rotor driven by an electric motor and provided with tapered journals received in tapered rubber bearings. Lubricating water flows to the bearings through metered openings in the journals, flowing from the openings through reverse spiral grooves in the journals which have diminishing cross section. The water flowing through the rotor also cools the rotor, as well as the collet driven by the rotor and a tool held by the collet. Rubber seals around the rotor shaft wear to a zero clearance during run-in for confining the water that exhausts from the bearings. Compressed air is introduced into the spindle to cooperate with the seals in preventing water leakage. The compressed air also reacts against a bladder that is arranged to impose an end load on one of the bearings, which is movable, to urge the bearing toward its journal. The force is varied to increase the bearing end load as rotor speed increases.

Abstract: Runout of a high speed, small diameter test rod in a drill spindle is measured by locating a pair of magnetic cores on opposite sides of the rod to establish a pair of magnetic circuits which include the air gaps between the rod and each of the cores. Coils on the cores are driven by square waves, which are differentially combined at the junction of the coils. The square waves have a frequency many times greater than the rotational speed of the rod, and amplitude of successive half cycles of the combined square waves are sampled after suitable delay times. The difference between the samples is a measure of the instantaneous rod runout while the rod is rotating. The instantaneous runout signal varies sinusoidally as the rod rotates and is peak detected to display the magnitude of the peak to peak voltage as a measure of rod runout.

Abstract: The collet includes a compressible basket having a central opening to receive a tool shank and two exterior surfaces tapering in opposite directions. One tapered exterior surface engages a matching tapered interior surface of a hollow rotatable shaft that receives it. The other tapered exterior surface engages a matching tapered interior surface of a wedge received in the shaft and movable axially relative to it. The angles of the tapers are such that they are self holding. The collet is closed by moving the wedge which compresses the basket sequentially at the two tapered surfaces, locking the tapers. The force on the wedge is released after this, leaving the tapers locked without external force as the tool is gripped in two locations during operation of it.