GB2178169A

GB2178169A - Examination of moving surfaces

Info

Publication number: GB2178169A
Application number: GB08614897A
Authority: GB
Inventors: Bernd Breuckmann; Werner Thieme
Original assignee: MAN Technologie AG
Current assignee: MT Aerospace AG
Priority date: 1985-07-27
Filing date: 1986-06-19
Publication date: 1987-02-04
Also published as: IT8648226A0; GB8614897D0; FR2585463A1; IT1234952B; DE3526923A1

Abstract

For rapidly monitoring the contour of a railroad vehicle wheel use is made of optical apparatus which directs at least one punctuate (laser) ray (14) onto a wheel (11) rolling along a rail (12) so that a line (15) illuminated on the wheel is detected by a detecting means, as for example a camera (16), for evaluation. <IMAGE>

Description

SPECIFlCATION A method and apparatus for the contactless examination of surfaces The invention relates to a method and an apparatus for the contactless examination of surfaces of moving objects in which a ray from a ray source is directed onto the object and the reflected ray is detected while relative motion between the ray and the object is taking place.

The unexamined German specification 2,356,491 describes an apparatus of this type designed to measure the amount of material on a conveyor belt. A linear ray source with a screen is arranged over the conveyor belt transversely in relation to it. A camera arranged at an acute angle to the conveyor belt detects the rays and the screen casts a shadow image over the conveyor belt so that a sharp outline of the pile of material on the belt may be seen in the camera image. The form and the amount of the material transported on the conveyor belt may then be derived from the image and the speed of the conveyor belt.

Such a method is restricted to particular applications and may not be generally used.

One object of the present invention is to devise a method, of the initially mentioned type, which may be used for examining the contours of objects whatever the form and the arrangement of the objects.

In order to achieve this or other aims appearing in the course of the present specification and claims, in the present invention a method for the contactless examination of the surfaces of a moving object is characterized in that a ray source is used to direct a punctuate ray on the object so that a ray is reflected and is detected while relative motion between the ray and the object is taking place.

The punctuate ray, which may more especially be a laser ray, on the one hand makes the use of a screen unnecessary and on the other hand means that such a ray may be directed onto surfaces of objects which are generally difficult of access. Owing to the motion of the object and/or of the ray a line or an area of the surface is scanned by the ray.

This provides the further advantage that the information of the reflected ray over a period of time may be stored directly without the production of an intermediate image, as video signal data. Naturaily it is also possible to record the contour on a photographic plate but then, in order to ensure a sharp image, it is not necessary to have bulky screens.

The method is preferably used for the mea surement or monitoring of the running faces of railroad vehicle wheels. In this case, the ray source is placed adjacent to the track in such a way that the ray is projected over the rail and the recording device is placed obliquely in relation to the running surface when the surface of the revolving wheel approaches the ray field.

The invention furthermore relates to an apparatus for performing the method which consists of at least one punctuate ray source and at least one device for detecting the reflected punctuate ray or rays.

The punctuate ray source or sources may be arranged so that they are able to move in at least one plane. The ray may be a laser rav. The apparatus may be installed stationarily adjacent to rails for carrying rail traffic in such a way that the ray source or sources direct the respective ray or rays over and above the rails.

One embodiment of the invention will now be described with reference to the accompanying diagrammatic drawing for examining the outer contour of railroad wheels.

For periodically checking the running surface 10 of railroad wheels 11 a monitoring unit is placed directly adjacent to a used railroad track. There is a ray source, as for example a laser 13 which is so placed that the punctuate laser ray 14 is directed over the rail 12 and, depending on the contour to be illuminated, extends normally or obliquely over the rail 12 at a height h within the wheel diameter.

For monitoring the running surface 10 of the wheel 11 the train is moved along the checking track at a certain speed so that the wheel 11 with an angular velocity of co passes through the ray 14 so that the ray shines on the running surface 10 of the wheel 11 along a line 15 (which is reflected as a ray 18) which owing to the motion of the wheel 11 runs transversely in relation to the contour of a cross section of the wheel. Using a detecting device 16, as for example an image camera which as far as possible is arranged normally to the line 15 of illumination, the illuminated line 15 is photographed on photographic material 17.

It is then possible to check the contour of the running surface 10 using a known method from the recording and also on the basis of the geometry of the measuring device, its position in relation to the wheel 11 and the angular velocity co By a comparison with reference images or reference contour parts of a wheel 11 it is then possible to measure the amount of wear of the wheel 10.

It is possible to record a set of contour lines 15 consecutively spaced out along the circumference of the wheel either by having a corresponding number of devices 13, 16, and 17 suitably arranged along the rail 12, or by causing one device 13, 16 and 17, after re cording one contour line 15, to move as a unit parallel to the rail in the direction of travel of the railroad vehicle.

It is also possible to move the ray source 13 synchronously with the wheel 11, if for facilitating processing a certain line direction is to be illuminated on the outer face of the wheel 11. A further modification of the invention is possible such that a number of sources of rays and a single camera or vice versa, or several ray sources and several cameras are used simultaneously. This is more especially desirable if more than one side of an object and not only a single side thereof are to be examined.

Claims

1. A method for the contactless examination of the surfaces of a moving object in which a ray source is used to direct a punctuate ray onto the object so that a ray is reflected therefrom and is detected while relative motion between the ray and the object is taking place.

2. A method as claimed in claim 1 wherein the ray is moved during the time in which it is detected.

3. A method as claimed in claim 1 or claim 2 wherein both the ray and the object are moved during the time in which the reflected ray is being detected.

4. A method according to any one preceding claim wherein said object is a wheel of a railroad vehicle.

5. A method as claimed in claim 4 wherein said object is a wheel of a railroad vehicle and the wheel is rolled along a rail and a ray field is directed over the rail so that the wheel is moved through said field.

6. A method as claimed in claim 1 substantially as described hereinbefore with reference to the accompanying drawing.

7. An apparatus for examining an object comprising at least one source adapted to produce a punctuate ray and to direct it on said object while there is relative motion taking place between said source and said object, and at least one ray detecting device for detecting said ray after reflection on said object.

8. An apparatus as claimed in claim 7 wherein said at least one ray source is adapted to be moved in at least one plane.

9. An apparatus as claimed in claim 6 or claim 7 wherein said ray is a laser ray.

10. An apparatus as claimed in any one of the claims 7 to 9 adapted to monitor the surface of wheels of a railroad vehicle, said apparatus being placed stationarily adjacent to railroad track with the at least one ray source so placed that the ray or rays therefrom may be directed over and above the rail.

11. An apparatus as claimed in claim 7 substantially as described hereinbefore with reference to and as illustrated in the accompanying drawing.