Device for detecting obstacles for rail vehicles

Abstract

A device for detecting obstacles for a rail vehicle includes a pilot bar, which is retained on the bogie frame of the rail vehicle in front of the wheelset that is positioned first in the direction of travel via a mounting retainer, wherein the mounting retainer is formed by vertically arranged spring elements, in particular leaf springs, where each leaf spring is fastened at an upper end to the bogie frame and at a lower end to the pilot bar, where each leaf spring includes a stress-strain converter which is arranged between the upper end and the lower end on a broad surface of a leaf spring, and where each stress-strain converter is connected to an on-board evaluator via a signal-conducting connection.

Claims

1. A device for detecting obstacles for a rail vehicle, comprising: a truck frame; a mounting bracket comprising a plurality of vertically disposed spring elements; and a pilot beam attached to a truck frame of the rail vehicle in front of a leading wheelset via the mounting bracket; wherein each spring element is fixed at an upper end to the truck frame and at a lower end to the pilot beam; wherein each spring element includes a stress-strain converter which is disposed between the upper end and the lower end on a broad surface of a leaf spring; and wherein each stress-strain converter is connected to an on-board evaluator via a signal carrying connection.

2. The device as claimed in claim 1, wherein the signal carrying connection passes via a measuring amplifier assigned to the stress-strain converter and wherein the measuring amplifier is disposed on the broad surface of the leaf spring.

3. The device as claimed in claim 2, wherein the stress-strain converter comprises a piezoelectric transducer.

4. The device as claimed in claim 1, wherein the stress-strain converter is configured as a strain gage.

5. The device as claimed in claim 4, wherein the evaluator is linked to a safety circuit and linked to an electronic vehicle bus.

6. The device as claimed in claim 1, wherein a speed signal of the rail vehicle is supplied to the evaluator, a braking operation being initiated based on said speed signal.

7. The device as claimed in claim 1, wherein the mounting bracket comprises two leaf springs spaced apart by a distance corresponding to a width of the truck frame of the rail vehicle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) For further explanation of the invention, reference will be made in the following section of the description to drawings from which further advantageous embodiments, details and refinements of the invention will emerge on the basis of non-limiting examples, in which:

(2) FIG. 1 shows an exemplary embodiment of the invention in which the hanging suspension of the pilot beam via two vertically disposed leaf springs is schematically illustrated;

(3) FIG. 2 shows an enlarged representation of a leaf spring from FIG. 1 in which the measuring device is shown enlarged; and

(4) FIG. 3 shows a block diagram illustrating the connection between the measuring device and evaluator and how they are linked into the safety circuit and vehicle bus.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

(5) FIG. 1 shows a schematic view of a truck frame 5 of a rail vehicle 1. The truck frame 5 has a front wheelset 11. Sketched in front of this wheelset 11 in the direction of travel (arrow) is a pilot beam 6 disposed at right angles to the direction of travel. This pilot beam 6 is fixed to the truck frame 5 via a mounting bracket 7.

(6) As will be explained in greater detail below, the mounting bracket 7 not only provides mechanical suspension for the pilot beam 6 but also acts as a force sensor which, in the event of a collision with an obstacle, transforms the collision force occurring into a proportional electrical signal and forwards it to an electronic evaluator.

(7) The mounting bracket 7 is formed as a suspended structure. In the example shown, the mounting bracket 7 basically consists of two vertically disposed spring plates or more specifically leaf springs 8. Each of these leaf springs 8 is formed from spring steel of rectangular cross section. This spring steel 8 is fixed at an upper end 9 to the truck frame. A lower end 10 of each leaf spring 8 is connected to the pilot beam 6 lying at right angles to the direction of travel. This can be a bolted, riveted or welded connection. In the event of a collision, each leaf spring 8 is subject to bending stress like a beam that is fixed at one end.

(8) The distance 17 between the leaf springs 8 corresponds approximately to the width of the truck frame. In the case of externally mounted trucks, the distance is somewhat greater than the track gage, and in the case of internally mounted trucks somewhat less than the track gage.

(9) With respect to their material properties and cross section, the leaf springs 8 are configured to ensure that the vibration and shock occurring particularly when the train is running at high speed do not interfere with the detection of obstacles.

(10) If a collision with an obstacle on the rail or tracked now occurs, the suspended structure is bent back in the direction of the wheelset 11. This deflection of the leaf springs 8 counter to the direction of travel is a measure of the size of the obstacle cleared away by the pilot beam 6. The elastic deformation of the spring steel 8 is measured by a measuring device 2, 3 (FIG. 2). By registering the time characteristic of the force signal during the collision, differentiated detection of the collision object is possible.

(11) A spatial arrangement of the measuring device 2,3 is schematically illustrated in FIG. 2. A stress-strain converter 2 with associated measuring amplifier 3 is shown on a broad surface 12 of a leaf spring 8. The stress-strain converter 2 and the measuring amplifier 3 are disposed between the upper end 9 and the lower end 10 on the same broad surface 12 of the leaf spring 8. Disposed at the upper and lower end are holes by which the leaf spring is bolted to the truck frame or pilot beam as the case may be.

(12) As previously stated, the arrangement of the leaf spring 8 and stress-strain converter 2 acts as a force-displacement transducer: the stress-strain converter 2 converts the elastic deformation of the leaf spring 8 occurring in the event of a collision with an object into a proportional electrical voltage signal. This voltage signal corresponds to an analog force-time characteristic. The signal is first supplied via the connecting line 4 to the measuring amplifier 3 assigned to the transducer 2. The measuring amplifier 3 locally boosts the signal of the stress-strain converter 2 to an appropriate analog level for making the forwarding of the signal as unsusceptible to interference as possible.

(13) The amplified electrical signal is then fed from the measuring amplifier 3 via connecting line 4 to an electronic evaluator 13 on-board the rail vehicle 1. The connecting line 4 is used, on the one hand, to power the transducer 2 and measuring amplifier 3 and, on the other, to convey the signal to the evaluation unit 13. In the following exemplary embodiment, the external unit is a digital computer.

(14) The signal is analyzed and compared in the evaluator 13 with a triggering threshold value dependent on the vehicle speed. If the conditioned measurement signal exceeds a predefined threshold value, then a safety circuit 15 is directly opened and emergency braking of the rail vehicle 1 is initiated. If the conditioned measurement signal remains below a predefinable threshold value, then an indication is sent to the driver via an internal vehicle bus 16. The threshold value is predefined by the evaluator 13 as a function of the speed and possibly other parameters, such as acceleration and shocks.

(15) The advantage of the invention is that a collision is monitored not only as a threshold value (as has been usual hitherto), but that an obstacle can be detected in a differentiated manner. As a result, the triggering threshold can be predetermined depending on the severity of the impact and as a function of the vehicle speed. This means that unwanted braking occurs less often.

(16) The spring steel mounting bracket is mechanically robust and simple to manufacture. Commercially available components can be used as stress-strain converters. A piezo or strain gage can be mounted simply and inexpensively by adhesively bonding it to the leaf spring. All in all, the manufacturing costs of the pilot beam suspension implemented as a force sensor are comparatively low.

(17) Although the invention has been illustrated and described in detail by the preferred exemplary embodiments presented above, the invention is not limited by the examples disclosed and other variations may be inferred therefrom by those skilled in the art without departing from the scope of protection sought for the invention.

(18) Thus, for example, the above described suspension comprising two leaf springs can be implemented by another suspended structure, e.g., having several leaf springs. The vertical arrangement of the leaf springs can also be slightly tilted. Self-evidently, the spring elements can equally well be fixed to a frame structure of the rail vehicle. Likewise, a plurality of transducers and amplifiers can be disposed on a leaf spring, thereby improving the reliability of the measuring device.

(19) Thus, while there have been shown, described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.