Bearings – Linear bearing – Roller bearing
Patent
1999-06-15
2000-12-26
Footland, Lenard A.
Bearings
Linear bearing
Roller bearing
F16C 1900
Patent
active
061648280
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention is directed to a mounting assembly for a machine tool carriage driven by linear motors on both sides of the machine tool.
A machine tool of the type which uses sliding carriages guided on rails on the machine tool frame is driven on both ends by linear motors. The sliding carriages work together to perform relative motion to one another as workpiece carriers as is known in German Patent 4307482 A1. Each sliding carriage is guided on a pair of parallel spaced main rails. The linear motors are mounted on both sides of the sliding carriage and turned 90.degree. laterally to the rails. Generally, the motors are mounted on a slide on one side and with an additional guide on the other side. Compensation of stresses and torsional forces is not provided by the slide mounting.
In German Patent 24 12 769 entitled "Column Guide for the Press Plate of a Press", it is known that a small bearing clearance can be achieved by guiding the press plate with bearing pairs on flattened surfaces on the columns so that the bearing pairs only are associated with two columns lying beside one another. Only a single bearing is associated with a further column, so that, of the six degrees of freedom of the press plate intended as a fixed body, five are guides. By this reduction of the guiding bearings from eight to five, the kinetic redundance in determination is eliminated and guidance independently of stresses and dangerous torques is achieved. However, application of the principle for the protection of linear motors running on rails from stresses or dangerous torques in a machine tool carriage as well as from accidental damage to the machine tool carriage appears to be only conditionally possible.
Therefore the object of the invention is to provide a novel mounting for a machine tool carriage driven by linear motors on both sides on fixed rails to compensate for stresses and torques on the machine tool carriage.
SUMMARY OF THE INVENTION
In accordance with the invention, this object is achieved by the features named in the first claim. Advantageous embodiments of the invention are the subject of the subclaims. The subject of the invention is a mounting assembly for a machine tool carriage driven with linear motors on both sides in the same direction. The linear motors are guided on fixed rails running parallel to one another. The linear motors carry friction contacts on which the machine carriage bridge is seated and against which it is pressed by its own weight and by spring force. The bridge is movable on the friction contacts by lateral forces which overcome the frictional force, and may be turned on the friction contacts. The bearing surfaces of the machine carriage bridge have apertures which are elongated in the longitudinal direction of the machine carriage bridge. For guiding the machine carriage bridge, the bearing surface at one end of the bridge has a bolt in a guide, while the other bearing surface has an elongated aperture. The spring force can be adjusted by special adjusting screws which are seated in the friction contact and surrounded by an open space in the bearing surfaces of the machine carriage bridge, and compression springs are disposed between the head of the adjusting screws and the bearing surfaces of the machine carriage bridge.
In the case of stresses in the machine carriage bridge or in the case of deviations of the rails from a parallel course, the lateral forces created in this case can be compensated by motion of the bearing surfaces of the carriage relative to the friction contacts guided by the elongated aperture. Accidents, in particular as a result of uneven starting of the motors, or even starting of the linear motors in opposite directions, are avoided by movement of the bearing surfaces on the friction contacts around the bolts. The operating position of the machine carriage bridge can be reached again after an accident by controlling a linear motor.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a fragmentary end elevational view in partial sectio
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Herrmann Rolf
Thonig Harry
Walden Matthias
Footland Lenard A.
Hansen Colby
Sachsische Werkzeug und Sondermaschinen GmbH
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