1. Field of the Invention
This invention relates to a measuring device for measuring workpieces, and more particularly to a measuring device which includes a base frame with a workpiece receiver to receive a workpiece to be measured, and at least one measuring unit to measure the workpiece.
2. Discussion of Prior Art
Such measuring devices are already well known in the state of the art. Thus there are, for example, so-called portal measuring devices which are usually constructed as follows. They include a base frame in the form of a baseplate, to which a workpiece receiver is fastened. By means of this, a workpiece to be measured can be fastened to the baseplate. A portal measuring unit is fastened to the baseplate for measuring the workpiece, and includes two guides which are fastened laterally of the baseplate, and on which a portal is guided which completely spans the baseplate. The portal can be moved along the baseplate over the guides. The spanning portion of the portal has, for its part, guides on which a slide can be moved transversely of the baseplate. In addition, guides are also provided in the slide. By means of the guides, a measuring arm, with a sensing head located on the measuring arm, can be moved up and down. Thus the sensing head can be moved in three mutually orthogonal directions by means of the above-described mechanism of the portal measuring unit. By means of the position of the sensing head, a workpiece to be measured can be measured in the x-, y- and z-directions.
Furthermore, so-called stand measuring units are also known from the state of the art. The stand measuring devices are essentially distinguished from the portal measuring devices solely in the design of the measuring unit. In contrast to a portal measuring device, the measuring unit in this case has a stand which runs on a guide fastened laterally of the base frame, so that the stand can be moved along the baseplate. The stand is in turn provided with guides, so that a slide can be moved up and down on it. The slide is furthermore provided with guides, by means of which a horizontally oriented measuring arm, with a head fastened to it, can be moved transversely of the baseplate. Workpieces can likewise be measured in three mutually orthogonal directions, x, y and z, by means of the said stand measuring device.
The special feature of the measuring devices known from the state of the art is seen to be that the measuring devices are rigidly fastened in their position. Portal measuring devices, for example, have a measuring arm which is oriented perpendicularly to the baseplate and is thus lowered onto the workpiece to be measured, and therefore can measure measurement points which are difficult to reach, such as, for example, lateral bores in a workpiece, only by the use of relatively expensive sensing heads. In particular, problems arise when different workpieces with differing geometry are frequently measured with one and the same measuring device, since for this purpose many special sensing heads often have to be provided.