Geometrical instruments – Gauge – Having a movable contact probe
Reexamination Certificate
1999-10-21
2001-08-28
Fulton, Christopher W. (Department: 2859)
Geometrical instruments
Gauge
Having a movable contact probe
C033S0010CC, C033S559000, C356S370000
Reexamination Certificate
active
06279246
ABSTRACT:
The invention concerns a method for determining the position of a point, in which use is made of a holder with, on the one hand, at least three reference points not in a straight line, whose positions with reference to each other are known, and on the other hand, a measuring point, where said measuring point is placed against the point whose position has to be determined, the position of said reference points is then measured, and, on the basis of the position of said reference points, the position of said point is calculated.
In the present state of the art, use is made of a holder whose measuring point is assumed to occupy at all times a fixed position with respect to the reference points. This frequently results in an inaccuracy in measuring the position of said point, since in some cases this position can alter.
The German patent application DE 3340317 describes a long holder provided with two reference points, which when measuring the position of the point has to be rotated about its axis. When said holder is rotated in this way, it unavoidably suffers an angular deviation, so that an imprecise measurement is made. Also, the distance from the measuring point to the reference points has to be measured manually with great accuracy in order to be able to determine the position of said measuring point, which can lead to errors that cannot be ignored. Furthermore, this distance also varies according to the flexure of the bar, with the result that in most cases a sufficiently accurate measurement of the position of a particular point is not possible.
The invention aims to overcome all these disadvantages by presenting a measuring system in which measurements can be carried out with very great accuracy.
To this end, use is made of a holder of which the position of said measuring point is determined by holding the latter in a fixed position, rotating the holder in various positions, then measuring the positions of the reference points for at least two different positions of the holder, and calculating the relative position of the measuring point with respect to the reference points from the measured positions of said reference points.
For that purpose, the position of said reference points can be advantageously measured several times for each position of the holder, with an average position being determined for at least three reference points, and the relative position of the measuring point or of said point is calculated from the average position of at least three reference points.
In an advantageous manner, the position of a point on an object can be determined by measuring the position of said reference points for at least one position of the holder, where the measuring point is placed against said point, and then calculating the position of said point, which essentially corresponds with the position of the measuring point, from the positions of the reference points.
In a particularly advantageous manner, light points, such as light-emitting diodes (LEDs) can be used for said reference points.
According to a particular embodiment of the method according to the invention, said reference points are observed from at least two different positions by preferably addressable camera.
The invention also concerns a device for measuring the position of a point, with a holder that is provided with at least three reference points and a measuring point, where said device comprises detectors which act with a calculation device so that the position of said reference points can be determined, more specifically by applying the method according to the invention.
According to a preferred embodiment of the device, according to the invention, said measuring point is provided with a measuring point which is detachably mounted on said holder.
According to a further preferred embodiment of the invention, said detectors comprise at least two addressable optical cameras.
Said reference points preferably consist of light points, more specifically light-emitting diodes (LEDs).
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Browdy & Neimark
Fulton Christopher W.
N.V. Krypton Electronic Engineering
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