Optima Industries, Inc.

Other

William F Marantette

Ruth B Marantette

Joseph E Smith

Roger Johnsrud

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.

Machine tool positioning arrangement

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. Thus a reference position of the bit is signalled and stored by the bit spindle control (18) that will move the bit longitudinally to a depth determined on the basis of the known bit reference position.

Drill bit position sensor

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. Three measured distances (C1, C2, C3) between the respective corner reflectors and three reference positions from which the three laser beams are projected enable calculation of the position of the moving corner reflectors, and, therefore, the related drilling spindles relative to a reference system.

Machine tool position measurement employing multiple laser distance

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.

Tool changer

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.

Arrangement for providing planar movement of a machine tool

An arrangement for driving a rotary tool is provided in which the tool shank is engaged and frictionally driven by the engagement of three or more drive rollers. Axial movement of the tool is accomplished by tilting the axes of the rollers as permitted by flexible portions of the shafts which drive the rollers. The tool is released by moving one roller away from the other two. A pressure foot is provided at the bottom of the assembly reciprocated by a cam arrangement to engage the workpiece when the tool is in operation. A position pick-off senses the axial position of the tool so that the tilt angle of the rollers can be controlled by a dual feedback path servo loop having an improved preconditioning circuit for its feedback position counter.

Arrangement for driving a rotary tool

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. The collet employs self-holding tapers to retain it in a closed position and has cam surfaces to help open it to the released position. The collet is retained by a removable member so that the collet can be removed and a broken tool shank extracted.

High speed drill spindle

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. An auto-centering compensation is provided to prevent the runout signal from saturating because of static offset of the cores from a precisely centered position on opposite sides of the rod. A signal representing the average position of the rod centerline during its rotation relative to the two cores is employed to modulate opposite phase square waves which are combined with the sensor output from the junction of the two coils so as to diminish the sensor output according to the amount of static offset.

Dynamic tube runout measuring method and apparatus with square wave

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. The collet is actuated by a pneumatic power cylinder with two pistons having portions that engage an extension of the wedge for moving it, after which these portions are spaced from the wedge extension so that they do not interfere with the operation of the tool. The position of the power cylinder is adjustable to assure clearance at the wedge extension.

Dual-plane high-speed collet

The system effects positioning of an art work at precise given X and Y rectangular coordinate points. This art work may correspond to drill hole positions in a printed circuit board. By recording in memory the exact rectangular coordinate points on the art work and the necessary servo signals to effect exact centering at the coordinate points, accurate circuit board drilling can be carried out. A circular hole is provided in the art work and an image of this hole projected to a screen having horizontal and vertical cross hairs defining X and Y axes respectively. The art work is precisely positioned at a given pair of rectangular coordinates when the intersection of the cross hairs corresponds exactly with the exact center of the image of the circular hole. Exact centering is achieved by causing first and second light responsive photo cells to oscillate along the X and Y axes directions respectively, the centers of oscillation of the cells corresponding to the intersection point of the cross hairs. If the projected image of the hole is off center, a cell or cells will be exposed to light longer on one side of its center position than on the other. Stated differently, the projected image will only be centered when the scanning cells are exposed to light for equal time intervals on either side of their center of oscillation positions. The difference in such time intervals is used to generate a corrective signal for operating the servos to effect precise center positioning.

Two axis centering system with oscillating photocells

The water powered motor includes a casing housing a rotor shaft. First and second water bearings of conical shape support opposite end portions of the shaft for high speed rotation. The central portion of the shaft has turbine wheels subject to high velocity water flow through the casing. The same high water pressure for driving the turbine also provides water to the water bearings to 'float' the rotor shaft so that very high speeds can be attained with minimum friction. The preferred application for the motor is that of a high speed drill for drilling printed circuit boards. However, it may be miniaturized for use as a dentist's drill.

Water powered high speed motor

The system includes a spindle for holding a high speed drill, the spindle being provided with longitudinal slots permitting its exterior side walls to be biased inwardly and grip the drill. Eccentric weights surround the spindle in such a manner that upon rotation of the spindle at a high speed, the weights are thrown radially outwardly to contract the side walls of the spindle by centrifugal force, thereby gripping the drill shank, the gripping force increasing with the speed of rotation of the spindle. For larger drills, a special collar is provided on the drill shank for engaging flats provided on the spindle to result in a positive locking of the drill shank for rotation with the spindle.

High speed drill system

A system for providing exact centering of an art work target at a given point to thereby provide exact positioning of a printed circuit board to be drilled, by way of example, combines visual as well as automatic electronic means for effecting the centering. The art work target in the form of an annular opaque pad with a clear center is projected onto a rear projection screen on which there are provided X and Y orthogonal axes the intersection point of which defines the exact point for centering of the art work target. Elongated photo cells are positioned quadrilaterally about the intersection point on the orthogonal axes, part of each of the photo cells lying in the opaque area of the target and the remaining portions lying in the clear center portion of the target. Shadows cast by these photo cells are visible on the rear projection screen so that a viewer can observe precisely what the photo cells 'see.' When the target image is precisely centered at the intersection point of the orthogonal axes, all of the signals from the photo cells will be equal. By utilizing difference signals between opposite photo cells aligned with X axis to drive an X servo motor and difference signals between the photo cells aligned on the Y axis to drive a Y servo motor, a table supporting the art work can be automatically moved in the X and Y directions to effect the desired precise centering automatically.

Projection scope and positioning system

A frame structure supports a work surface above which there is provided an elongated head number supporting a series of drills. A torque tube having an axis parallel to and spaced from a line passing through the series of drills is mounted to the frame structure for rotation about its axis. The drill head member is coupled to the torque tube such that rotation of the torque tube initially swings the head member in an arc and thereafter urges the head member through a lost motion coupling arrangement against a pair of spaced parallel guide rails, secured to the frame structure normal to the work surface so that the remaining travel of the drill head is rectilinear. The stiffness of the torque tube assures that one end of the elongated drill head will not move ahead or drop behind the other end so that all holes are drilled simultaneously.

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Torrance, CA, United States of America

William F Marantette