DE2236489A1 - DEVICE FOR MEASURING THE MOVEMENT OF A BODY IN RELATION TO ANOTHER BODY - Google Patents

Description

CGiürAGHIü; (LÜTSHALE I) ¹ ELUGIiSiIGI ^

5'I-, rue IcC i3ü6tio, Paris G, jprankroicli

Device for measuring the movement of one body in relation to another body

The invention relates to a device for measuring the movement of one body with respect to another Body.

There are already numerous devices for measuring the movement of one body relative to another Body known, but none of which is really simply structured and easy to use and at the same time can be manufactured at low cost and gives very good results.

The aim of the invention is to provide a device of simple construction that can be produced at low cost Measuring the movement of one body in relation to another body to create · which works very reliably and very well is easy to use.

209886/0929

The invention relates to a device for measuring the movement of one body with respect to another Body, which is characterized by a photosensitive carrier on which the hologram of a scale is recorded -is and which is firmly connected to one of the two bodies, a light beam source for illuminating the Holograms at a substantially constant angle when one of the bodies moves relative to the other, and means, fixedly attached to the other body, for point-like sighting of the illuminated by the Hologram reproduced image.

Further details and advantages of the invention emerge from the following description of an exemplary embodiment, reference being made to the accompanying drawing. The drawing shows a schematic representation a device according to the invention for measuring the movement of a body relative to another body.

The device shown in the drawing is used to measure the linear movement of a carriage, for example 1, which can move with respect to a base 2, for example with the help of wheels 2 and 4, each run on a rail 5 or 6 attached to the base 2.

The device has a photosensitive carrier or a photosensitive plate 7 on which, for example the hologram of a scale is recorded, for example such as a known scale or a micrometer is provided with numbered, regularly spaced markings. The photosensitive plate 7 is firmly connected to the carriage 1 and can be taken along by this in a straight line movement or in any movement will. A light source 8 supplies a light beam 9 * the

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widened for example by an afocal device 11 can be. This light beam 9 illuminates the plate 7 at an essentially constant angle, when the carriage 1 moves relative to the base 2. In the case of strong relative movements, the light source 8 is preferred with the carriage 1, in the case of movements of low amplitude it is firmly connected to the base 2. The only condition is here that the light beam 9 hits the plane of the plate 7 at a substantially constant angle hits.

The device also has sighting devices, for example a telescope Io with a line cross, which is firmly connected to the base 2 and is directed so that its optical axis 12 has a constant orientation and is always directed essentially towards the image 11, the outline of which is shown in broken lines on the drawing is shown. When the carriage moves, it takes the photosensitive plate 7 and thus the image 11 with it, which thus seems to be firmly connected to the carriage 1. An advantage of the invention is that thanks to the Holor graphics on a photosensitive plate 7 with very small dimensions, the hologram of a measuring scale with large dimensions can be recorded; for example, a ruler lom in length is recorded on an im length hologram. It is known that in the known technique of holography, the image of the recorded object is in the real size, whereby the size of the disk on which the hologram is recorded does not matter. Another advantage of the invention is that absolute, non-incremental measurements can be made, because the hologram allows for an enlargement. This gives dte for entering counts between the Graduations required basis.

_ 4 209880/092 $

The device works in the following way: For example, the linear movement of the carriage 1 can be measured with respect to the base 2.

The hologram recorded on the plate 7 and illuminated by the light beam 9 generates the image 11, which is preferably the image of a rule with numbered graduations in meters, centimeters or microns. If the car is in its starting position, the first thing to do is to look through the sighting telescope Io notes the number of the marking whose image coincides, for example, with the cross. After a Movement of the carriage, the number of the graduation is noted, which in this new position with the cross of the telescope Io collapses. Then there is only the difference between the graduation of the first position and to determine that of the second position, from which the movement of the carriage 1 relative to the base 2 results.

With this device, movements of all kinds, such as linear movements or movements, can be carried out in a simple manner on curved paths, provided that the possible movements of one body relative to another are measured are known in advance. The hologram can by a coherent and monochromatic light source, for example a laser. In order to reduce the production costs, however, the holograms can also be used Common light sources are illuminated with the aid of some improvements, for example by these an interference filter and a diaphragm with a small opening are added with which to make one of the image of the hologram sufficient coherence can be achieved. All kinds of images can be placed on the hologram be recorded with which a movement can be determined, provided the distance between any two

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Points of this image can be determined.

Such a device is in numerous areas, in particular for measuring the movements of the Machine tool slides, applicable. In this field of application namely hinders the deposition of Dust, even from opaque dust, on any part of the disk on which the hologram is recorded, not reading the graduations. " This has only a very small loss of the luminosity of the reproduced Resulting in an image.

The invention is not restricted to the exemplary embodiment described and illustrated above. In particular some arrangements can be changed within the scope of the invention or some means by other appropriate means Funds to be replaced.

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Claims (3)

Claims lj Device for measuring the movement of a body relative to another body, characterized by a photosensitive carrier on which the hologram of a scale is recorded and which is firmly connected to one of the two bodies, a light beam source for illuminating the hologram at a substantially constant angle when one of the bodies moves with respect to the other, and devices fixedly attached to the other body for point-like sighting of the image reproduced by the illuminated hologram. 2. Apparatus according to claim 1, characterized in that g e k θ η η shows that the sighting devices consist of a telescope with a cross. 3. Apparatus according to claim 1, characterized in that the light beam source consists of one Laser exists. 209886/0929