Unova IP Corp.

Western Atlas Inc.

Joel Metzler

William W Pflager

Timothy W Hykes

A machine tool comprising a base, with a guide surface, a workpiece holder on the base, a movable tool carriage, and a motor for advancing the carriage along the guide surfaces toward the workpiece. Hydrostatic bearings are situated in the carriage for discharging fluid, such as oil, into the narrow gap defined between the carriage and the guide surface. A pre-load rail is secured to the movable carriage, and a plurality of pockets are defined in the pre-load rail. A hydrostatic pre-load piston, with an enlarged head and a depending base, is located in each pocket. A shallow depression is formed in the face of each piston, and an annular wall surrounds the depression, so that the piston restores itself to an equilibrium condition. The pre-load pistons are located in opposition to the hydrostatic bearings. An O-ring encircles the base of the piston, and allows floating, and tilting, movement of the piston within the pocket, while serving as a seal for the pocket. The individual pre-load pistons float and tilt to accommodate diverse localized distortions, anomalies, imperfections, and machining errors in the carriage and in the guide surface.

Hydrostatic pre-load piston

An improved drive and support for a machine tool by which a part thereof can be supported and driven along a linear path for machining. The drive and support includes a linear slideway having a magnetic track along which a housing will move when a moving magnetic field is generated in an electromagnetic assembly mounted in the housing. The direction the housing moves depends upon the direction of movement of the generated magnetic field, and first hydrostatic bearing pads acting between the housing and the slideway, or between the electromagnetic assembly and the track or any combination thereof, to counteract the attractive force between the electromagnet and the track.

Drive and support for machine tools

A machine tool comprising a base, with a guide surface, a workpiece holder on the base, a movable tool carriage, and a motor for advancing the carriage along the guide surface toward the workpiece. Hydrostatic bearings are situated in the carriage for discharging fluid, such as oil, into the narrow gap defined between the carriage and the guide surface. A pre-load rail is secured to the movable carriage, and a plurality of pockets are defined in the pre-load rail. A hydrostatic pre-load piston, with an enlarged head and a depending base, is located in each pocket. A shallow depression is formed in the face of each piston, and an annular wall surrounds the depression, so that the piston restores itself to an equilibrium condition. The pre-load pistons are located in opposition to the hydrostatic bearings. An O-ring encircles the base of the piston, and allows floating, and tilting, movement of the piston within the pocket, while serving as a seal for the pocket. The individual pre-load pistons float and tilt to accommodate diverse localized distortions, anomalies, imperfections, machining errors, and the like, in the carriage, and in the guide surface.

A spindle, comprised of a spindle body and an indexing fixture, is configured to retain, and rotatingly drive, a crankshaft relative to a grinding tool, so that each pin on the crankshaft is ground with a high degree of precision. A locking mechanism, such as a pair of jaws with complementarily shaped teeth, is interposed between the spindle body and the indexing fixture. Pressure is applied to one side of the locking mechanism so that the jaws are normally engaged and the spindle body and the indexing fixture rotate as a unit. Motive power for such fixture is supplied by a single servomotor secured to a primary drive shaft, which is joined to a secondary drive shaft, through an offset coupling, to define a motorized spindle. The indexing fixture is bolted, or otherwise secured, to the free end of the secondary drive shaft. A bearing block in the indexing fixture receives and retains, the main shaft of the crankshaft; clamping arms with clamp shoes press the shaft downwardly into the bearing block. To place a pin on the crankshaft in position to be ground, pressure is supplied intermediate the jaws of the locking mechanism to force same apart. The secondary drive shaft then rotates the uncoupled indexing fixture relative to the spindle body to place an unground pin in a position to be ground by a grinding tool operatively associated with the motorized spindle. Keys and keyways are formed between the spindle body and the indexing fixture. A threaded bolt, and the cooperating nut, allow limited movement between such components to adjust the throw for pins located at different elevations along the crankshaft to be ground. A zero angle reference point is established by milling a reference pad on a crank pin web situated between the main bearing shaft and the first pin on the crankshaft.

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Greencastle, PA, United States of America

Joel Metzler