DE8809826U1 - Feed device for linear movement of a length measuring probe - Google Patents

Description

PATENT ATTORNEYS

Dipt.-&Igr;&pgr;&bgr; Sigurd Leine Dipl Phys Or NoröerS Konig

BurcMiarrJtstraBe 1 Telephone (OS 11) 623005

D-3000 Huinover t Our sign date Hommelwerke GmbH 820/108 27 July 1988

Feed device for linear movement of a length measuring probe

The innovation relates to a feed device of the type mentioned in the preamble of claim 1 for scanning the shape of a surface of a workpiece along a scanning line,

In feed devices of the type in question, guide errors when guiding the length measuring probe along the surface of a workpiece affect the measuring accuracy. For this reason, the guides of the feed rate for moving a length measuring probe over the surface of a workpiece to measure the surface shape of the workpiece is manufactured with high precision and is therefore expensive. Measuring errors due to guidance errors cannot be avoided, they can only be kept small by high precision become.

From OE-PS 35 43 906 a device for measuring the shape of a surface along a scanning line with a feed device according to the preamble of claim 1 is known. The feed device has a Sensors for recording the values of the length measuring probe in a path-correct manner. Means for removing guidance errors are not provided.

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The aim of the innovation is to create a feed device of the type in question which enables a complete correction of the measured values with regard to errors resulting from guidance errors of the mechanical feed device.

The problem underlying the innovation is solved in a feed device by the teaching specified in claim 1.

The basic idea behind the innovation is to determine and save the unavoidable guide errors in a path-dependent manner, so that they can be added to the measuring voltage later when measuring the surface of a workpiece, which is then completely freed from guide-related measurement errors. The innovation is explained in more detail using the drawing.

€ will be.

A feed device 1 has a rod 2 which is guided in an x-direction indicated by an arrow 3 and is movable by drive means not shown. The rod 2 is also assigned a displacement sensor within the feed device 1, which a line 4 emits path-dependent signals which are applied to a correction memory 6 via a line 5.

At the outer end of the rod 2 there is a holder 7 for a measuring probe 8, which has a measuring arra 10 that can be pivoted about a pivot bearing 9, at the end of which a probe tip 11 which rests on an ideal surface 12 of a standard piece 13.

The measuring probe 8 emits measuring signals, usually a measuring voltage, via a line 14, which correspond to the movements of the

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Probe tip 11 and can be fed to the correction memory 6 via a switch 15, when this is closed.

The line 14 also leads to an addition input 16 of an addition device 17, the other addition input 18 of which receives correction signals from the correction memory 16 via a line 19.

When using the device shown in the drawing, the standard piece 13 with its ideal surface 12 is first brought under the probe tip 11 in the manner shown and then a measuring run is carried out with the switch 15 closed, so that the measuring voltage of the measuring probe 8 emitted on the line 15 is stored in the correction memory 6. If one assumes that the surface 12 is really ideal, or very close to it, it follows that the values stored in the correction memory 6 can only be based on guide errors of the rod 2. If the surface of a real workpiece is to be tested, this is brought with its surface under the probe tip 11 and a scanning run is carried out while the switch 15 is open. In this case, the position sensor of the feed device 1 controls, via lines 4 and 5, the correct output of correction values from the correction memory 6 via line 19 and addition input 18 to the addition device 17, at whose addition input 16 the measuring signals from the measuring probe are present, which originate from the measured surface of the workpiece. Corrected measuring signals thus appear on the output line 20 of the addition device 17, which are free of electrical errors caused by mechanical guide errors of the rod 2.

The appropriate processing and storage of measurement signals, as is also done in this invention, are generally state of the art and are described, for example, in the aforementioned DE-PS 35 43 906.

Claims (1)

Claim Feed device for the linear movement of a length measuring probe for scanning the shape of a surface along a scanning line, with a rod which is movably held in a guide and connected to a drive device and has a holder for a length measuring probe and a displacement sensor which emits signals dependent on the displacement position of the rod, characterized by a correction value memory (6) connected to the displacement sensor and connectable to a length measuring probe (8), in particular a digital one, for storing the values of the deviation of the path of the holder (7) and thus of a length measuring probe (8) from a straight line depending on the movement location of the holder (7), an addition device (17) which is connected to the displacement sensor and to whose one addition input (18) the correction value memory (€) and to whose other addition input (16) a length measuring probe (8) held by the holder (7) are connected or can be connected and which adds the values of the deviations with the correct sign in the sense of a correction of the length values of the length measuring probe (8) to these location-dependently, such that at the output of the -2- Addition device which is affected by the deviations The values of the length measuring probe (8) can be removed.