WO1997004290A1

WO1997004290A1 - Transducer bar

Info

Publication number: WO1997004290A1
Application number: PCT/SE1995/000882
Authority: WO
Inventors: Sören HÅLLBERG
Original assignee: Haallberg Soeren
Priority date: 1995-07-21
Filing date: 1995-07-21
Publication date: 1997-02-06

Abstract

On rail tracks equipped with strain gauges, sensor elements are attached directly to the rails by bonding or welding and are then connected electrically, which may be carried out either at site or as part of the prefabrication of rails at the factory. Both methods involve considerable work on the track, which disrupts and is disrupted by rail traffic. The aforementioned problems also arise in the course of tracklaying and track maintenance work, The invention solves this problem by mounting prefabricated sensor beams on the rails using bolts and nuts.

Description

TRANSDUCER BAR

The invention relates to a device as described in the introduction to patent claim 1.

On rail tracks equipped with strain gauges, sensor elements are attached directly to the rails by bonding or welding. The rails must first be cleaned and the sensor element mounting surface carefully ground to ensure that it is even. After grinding, the sensor element mounting location is marked off in the neutral plane and is cleaned thoroughly. The sensor elements are attached by bonding or welding, and are then connected electrically. Following connection, the elements and connection points are provided with moisture protection and physical protection. The mounting operation must be carried out with great care and in good weather conditions, which may be difficult to assure outdoors. The altemative is to prefabricate the rails, with the sensor elements attached, in the factory, which causes major disruption to rail traffic when the prefabricated rails are subsequently laid on the track. The same problems arise in the course of tracklaying and track maintenance work.

The present invention relates to a sensor device for indicating static or dynamic load, preferably from railbound vehicles.

Examples of the mechanical arrangement, electrical arrangement and installation are shown in Fig. 1, Fig. 2 and Fig. 3 respectively.

As shown in Fig. 1, the sensor beam consists of a base (1) with strain gauges (2) attached, together with moisture protection as well as physical protection. The sensor beam is mounted on the object in which the load is to be measured by means of bolts and nuts or, alternatively, by bonding or welding. When the measured object is subjected to a force, the resultant deformation of the rail is transmitted to the beam, whose sensor element registers the deformation and converts it into an electrical signal.

When mounting the sensor beam on the rail, the latter may be drilled using a template, eliminating the need for precise marking out. The sensor is then mounted on the web of the rail by means of bolts and nuts. Fig. 3 shows two sensors, one mounted on each side of the web. This operation can normally be carried out without disruption to rail traffic; mounting of the sensor can be carried out very quickly and the work can be completed regardless of the weather.

Claims

PATENT CLAIMS

1. Device designed for recording static or dynamic load on an object, preferably a rail, consisting of a sensor base (1) provided with sensor elements (2), such as strain gauges, for shear measurement, together with connection leads, moisture protection and physical protection, characterised in that the sensor base is provided with at least three mounting holes perpendicular to the plane of the sensor element, positioned so that at least one mounting hole is located on each side of the sensor elements, for mounting the sensor on the object on which the forces are to be measured.

2. Device in accordance with patent claim 1 , characterised in that the sensor elements are connected in the form of a Wheatstone bridge (Fig. 2).

3. Device in accordance with patent claim 1 , characterised in that a device is mounted on each side of the rail to increase the accuracy of measurement (Fig. 3).

4. Device in accordance with patent claim 2, characterised in that the sensor elements form one half of a Wheatstone bridge, the other half consisting of resistances to detect the passage of axles.

5. Device in accordance with patent claim 1, characterised in that the sensor base is provided with reinforcement at the mounting holes to distribute the force from the mounting bolts in the holes to the sensor base.

6. Device in accordance with patent claim 1 , characterised in that the underside of the sensor base around the mounting holes is raised to ensure that the sensor base bears against the measurement object only at the mounting points.

7. Device in accordance with patent claims 1-6, characterised in that the sensor is provided with an additional mounting hole for another type of sensor, such as an accelerometer, for recording wave propagation in the measurement object. In this case, the signals received from the sensor are clearly recognisable from each other in time.

8. Device in accordance with patent claim 7, characterised in that the sensor elements are compensated for temperature variations.

9. Device in accordance with patent claim 8, characterised in that the sensor base is provided with four mounting holes.

10. Device in accordance with patent claim 9, characterised in that the sensor base is welded to the object at interfaces between base and object, or that the sensor base is bonded to the object.

On rail tracks equipped with strain gauges, sensor elements are attached directly to the rails by bonding or welding and are then connected electrically, which may be carried out either at site or as part of the prefabrication of rails at the factory. Both methods involve considerable work on the track, which disrupts and is disrupted by rail traffic. The aforementioned problems also arise in the course of tracklaying and track maintenance work. The invention solves this problem by mounting prefabricated sensor beams on the rails using bolts and nuts.