Geometrical instruments – Gauge – With calibration device or gauge for nuclear reactor element
Reexamination Certificate
2000-01-10
2001-08-07
Fulton, Christopher W. (Department: 2859)
Geometrical instruments
Gauge
With calibration device or gauge for nuclear reactor element
C073S001790
Reexamination Certificate
active
06269544
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an apparatus for measuring three-dimensional(hereinafter referred to as “3-d”) volumetric errors in a multiaxis machine tool with multiple freedom of degrees, and more particularly to an apparatus for measuring components of both static errors and dynamic errors in such a multiaxis machine tool to assess the error components and to compensate for the 3-d volumetric errors affecting the operational precision of the machine.
Recently, development of efficient techniques for performance verification of the multiaxis machine tools has been considered as an important task for accuracy enhancement and quality assurance for users and manufacturers of multiaxis machine tools and coordinate measuring machines. In order to perform precise position control and to promote accuracy of the multiaxis machine tools, the development of efficient techniques is directed to compensation of the 3-d volumetric errors or volumetric errors, since it is very essential to measure and analyze each error component and to compensate the 3-d volumetric errors.
The static errors include geometric errors, kinematic errors, and thermal errors, etc. and dynamic errors include errors due to servo gain mismatch and dynamic characteristics. Such 3-d volumetric errors which are generated during the operation of the multiaxis machine tool directly affect the machining precision in addition to the measuring precision of the machine tools as described above. Therefore, it has been well known to the manufacturers and users of multiaxis machine tools that the technique precisely and effectively measuring and assessing the 3-d volumetric errors in such machine tools is a prerequisite for accuracy enhancement and quality assurance.
The basic construction of the 3-d volumetric error measuring apparatus according to the present invention is accomplished by a kinematic ball bar consisting of a pair of balls. Such a kinematic ball bar has been well known to those skilled in the art as disclosed in U.S. Pat. Nos. 4,435,905, 5,052,115 and 5,214,857. Such a conventional 3-d volumetric error measuring apparatus uses a longitudinal bar, so-called “kinematic ball bar” which is provided with a ball at each end. Of the two balls, the first one is engaged with a socket of a movable toolholder, while the second one is engaged with a socket of a fixed workholder. In an operation of the machine tool, the toolholder moves while tracing a circle around the ball being engaged with the socket of the workholder.
However, the apparatus of the above U.S. patents are different from each other in that they have different constructions and different driving mechanisms except for the above-mentioned basic construction with a kinematic ball bar. Each apparatus of the above U.S. patent thus has intrinsic operational characteristics in addition to merits and demerits.
In the same manner as disclosed in the above U.S. patents, the apparatus according to the present invention has a kinematic ball bar provided with a ball at each end. However, the apparatus of the present invention is characterized in that it has an intrinsic driving mechanism which is designed to be used with the two balls in the measurement of the 3-d volumetric errors in multiaxis machine in a way different from those of the above U.S patents.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an apparatus for measuring three-dimensional volumetric errors in a multiaxis machine tool which has a newly designed and intrinsic driving mechanism in the two balls provided at both ends of a kinematic ball bar.
According to the present invention, this object is achieved. There is provided an apparatus for measuring three-dimensional volumetric errors in a multiaxis machine tool comprising, a ball bar having a predetermined length and provided with a displacement sensor therein, and having a movable contact member at an outside thereof with an outside end surface of the contact member being flat; a U-shaped bar having two opposite extension arms and integrated with one end of said ball bar, each of the extension arms having a hole at a predetermined position with an operating pin being fitted into the hole; a first ball provided at the other end of said ball bar and detachably set in a stationary magnetic socket assembly; a second ball positioned to have always a ball and flat contact with the flat end surface of the movable contact member of the sensor; a vertical post perpendicularly positioned relative to said U-shaped bar and integrated with said second ball at a lower end thereof; a sleeve fitted over said post; and two guide bars fixedly and longitudinally assembled with an external surface of said sleeve at opposite positions, each of said guide bars being provided with a slot at a lower portion thereof for movably receiving the operating pin.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure.
For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which the preferred embodiments of the invention are illustrated.
REFERENCES:
patent: 4435905 (1984-03-01), Bryan
patent: 4884348 (1989-12-01), Zeller et al.
patent: 4982504 (1991-01-01), Soderberg et al.
patent: 5052115 (1991-10-01), Burdekin
patent: 5111590 (1992-05-01), Park
patent: 5214857 (1993-06-01), McMurtry et al.
patent: 5647136 (1997-07-01), Jostlein
patent: 61-209857 (1986-09-01), None
Kim Young Sam
Pahk Heui Jae
Fulton Christopher W.
Lowe Hauptman & Gilman & Berner LLP
Snu Precision Co., Ltd.
LandOfFree
Apparatus for measuring three-dimensional volumetric errors... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for measuring three-dimensional volumetric errors..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for measuring three-dimensional volumetric errors... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2513138