Device for detecting crossties of a track

Description

Technical field

[0001] The invention relates to a device for detecting sleepers of a track, comprising a sleeper detection sensor which can be arranged on a track construction machine, optionally on a track measuring car assigned to the track construction machine, for measuring and determining the position of sleepers in the track. State of the art

[0002] Such sleeper detection sensors are used in particular to measure and determine the position of metallic fasteners that connect the rail to a sleeper, which also allows the position of the sleeper to be clearly determined.

[0003] Tamping machines are machines that correct the track geometry. They use measuring systems that measure the actual track height and direction, as well as the actual cant, during operation and compare them with specified target values. Using a track lifting and straightening unit, the track panel is raised and laterally aligned until the difference between the specified target position and the actual position is zero. The track panel is then secured in this position by compacting the ballast beneath the sleepers using a tamping unit. The lifting and straightening of the track panel is achieved using appropriate hydraulic lifting and straightening cylinders with proportional or servo controls. The tamping tools of these types of track maintenance machines must be precisely inserted into the gap between the sleepers to prevent destruction or damage to the sleepers. Therefore, great attention must be paid to the precise positioning of the tamping machine and its tools.Automatic positioning and priority of track construction machines is possible if the sleepers are visible and not covered by a layer of ballast.

[0004] In addition to maintenance work, tamping machines are also used to tampe new track, after ballast cleaning work, or after track reconstruction. This work involves multiple tamping passes. These tamping passes are typical for the track to be ballasted up to the top of the rail, and the tamping machine performs large lifts. The position of the sleepers is only roughly visible to the operator during the lift due to the pronounced unevenness of the ballast. The problem is that the tamping machine operator can only determine the machine's forward travel and the positioning of the tamping tools over the intermediate bay based on feel and experience. Automatic forward travel is practically impossible. If the tamping tools are not positioned correctly, the sleeper will be hit and damaged. Another disadvantage is that the machine's performance is severely impaired.

[0005] Various optical systems, such as laser scanners or video cameras, can detect the position of the rails, sleepers, and rail fastenings. This also enables automatic, precise positioning of the tamping tools and the advance of the tamping machine. However, conventional optical methods fail on tracks that are ballasted up to the top of the rail.

[0006] Another problem with tracks ballasted up to the top of the rail is that the operator fails to detect obstacles in the intermediate compartment, such as those often found in turnouts, such as switch drives, switch rods, and switch locks, and damages them during the plunge process with the tamping units. Optical measuring methods are also of no help here.

[0007] Conventional inductive and capacitive analog sensors have a maximum detection distance of approximately 30 mm. However, the distance between the top edge of the rail and the height of the rail fastenings to be detected is much greater, which means that such sensors have not been useful to date. Therefore, guiding an inductive sensor, for example, is problematic because it would have to be installed deep and thus moved through the ballast. Another difficulty is that the fastenings have different heights depending on the type, which is also problematic given the short measuring distances. In practice, there are many different rail fastenings. They are characterized by the screw connection and that the fastenings are at least predominantly made of steel (ferromagnetic).These fasteners are located in close proximity to the rail, have low ferromagnetic mass, and are sometimes so far below the top of the rail that they cannot be reliably detected with conventional inductive or capacitive sensors. In principle, if they are lowered sufficiently close to the fasteners for measurement, they can detect them. However, if the ballast extends up to the top of the rail, such solutions are practically impossible.

[0008] Such a device is known from WO2019 / 068400A1. Description of the invention

[0009] The invention is therefore based on the object of finding a detection device and an arrangement which avoids the disadvantages mentioned above and which clearly detects the rail fastening means even when fully ballasted at a large distance (above the ballast) to the rail fastening means.

[0010] The invention achieves this objective by providing a sleeper detection sensor with a magnet generating a magnetic field in a magnetic circuit with at least one air gap between the sleeper detection sensor and the track, and a Hall sensor arranged in the magnetic circuit, whose Hall voltage, varying in the longitudinal direction of the track, serves to determine the position of the sleepers in the track. Advantageous developments of the invention are presented in the subclaims.

[0011] An electromagnet and / or permanent magnet generates a magnetic field in the magnetic circuit. This field is measured by a Hall sensor through which current flows. The Hall sensor's Hall voltage increases with the presence of a rail fastening due to the reduction in magnetic resistance. This increase is used to determine the position of the rail fastenings and thus of the sleepers in the longitudinal direction of the track and to control the automatic advance of a track maintenance machine. Essentially, the air gap and thus the magnetic resistance change depending on whether a rail fastening or, where appropriate, other metallic obstacles, such as switch drives, are present or not, as is particularly the case between two sleepers.The course of the Hall voltage over the track length, i.e. the respective position of the sleeper detection sensor in the track, is used to determine the position of the rail fastening and thus of the sleepers in the longitudinal direction of the track.

[0012] The magnetic circuit closes between two sleepers across the rail. If a rail fastening enters this magnetic range, the magnetic resistance decreases and the magnetic field increases. Since the measurement of the rail fastening and thus the change in the magnetic field and the position of the sleepers takes place several sleepers before the tamping units are positioned, the signal can be evaluated in advance and the center position determined.

[0013] For a magnetic field, the vector Lorentz force applies: F L → = Q ⋅ v → x B → FL ... Lorentz force Q ... Charge v ... Velocity of charge carriers B ... Magnetic field

[0014] A Hall effect sensor operated with a known current I measures the magnetic field component B y occurring orthogonally to its surface. This creates an electric field E x . The voltage U can be measured on the side surfaces proportional to this. The sleeper detection sensor is mounted on a carrier carriage and guided at a constant height above the rail and rail fastenings. The distance traveled and the Hall voltage are continuously measured. The signal is evaluated. For this purpose, a limit value is progressively determined based on the difference between the base level and the peak value of the signal. The mean value of the signal at this limit value gives the mean position of the rail fastening and thus the position of the sleepers. The measured distances ai from sleeper to sleeper are used to control the advance and position the tamping tools.

[0015] An advantage of this inventive design is the ability to measure through a layer of ballast, allowing precise positioning of the tamping tools. This allows the tamping machine to operate at high speed in automatic advance mode. The arrangement can also detect obstacles made of ferroelectric material, such as drive rods for switches in the intermediate compartment, using several sleeper detection sensors arranged side by side on the wagon. Brief description of the invention

[0016] The subject matter of the invention is shown schematically in the drawings. Fig. 1 a partially sectioned cross-section of a sleeper with rail and W-fastening, Fig. 2 a partially sectioned cross-section of a sleeper with rail and K-fastening, Fig. 3 schematically the structure of the threshold detection sensor with magnetic field, Fig. 4 the basic structure of a Hall effect sensor, Fig. 5 schematically shows the measurement process and the resulting voltage signal at the Hall sensor. Ways to implement the invention

[0017] Fig. 1 shows a cross-section of a rail 1 screwed onto a sleeper 5 at a 1:40 incline. The sleeper screw 2, the tension clamp 3, the angled guide plate 4, and the intermediate layer 6 are shown in elevation. The tension clamp 3, the sleeper 5, and the sleeper screw 2 are made of steel and thus influence a change in the magnetic flux when a sleeper detection sensor is moved along the rail 1. This allows their position in the longitudinal direction of the track, or their longitudinal position in the track, to be clearly detected.

[0018] Fig. 2 shows another type of rail fastening, the so-called K-fastening (clamping plates). Rail 1 is bolted to sleeper 5 at an incline of 1:40. The hook bolt 7 with fastening nut, clamping plate 8, sleeper bolt 9, ribbed plate 10, and elastic intermediate layer 6 are shown. Hook bolt 7, ribbed plate 10, and clamping plate 8 are made of steel and reduce the magnetic resistance when a sleeper detection sensor passes over the K-fastening.

[0019] Fig. 3 shows a schematic of the measurement setup of a sleeper detection sensor 11 in question, which is arranged on a track construction machine (not shown in detail), possibly on a track measuring carriage assigned to the track construction machine, for measuring and determining the position of sleepers 5, 19 in the track. The sleeper detection sensor 11 comprises an electromagnet 12 generating a magnetic field in a magnetic circuit with at least one air gap between the sleeper detection sensor 11 and the track, and a Hall sensor 13 arranged in the magnetic circuit. The Hall sensor 13 is arranged in this air gap between the sleeper detection sensor 11 and the track. The Hall voltage U, which changes when the sleeper detection sensor 11 is moved in the longitudinal track direction A, s, i.e. along the track, serves to determine the position of the sleepers 5, 19 in the track.

[0020] The sleeper detection sensor 11 is equipped with an electromagnet 12. A magnetic field 14, 15 is generated via an electric coil of the electromagnet 12 and a magnetic core 11, in particular a soft iron core of the sleeper detection sensor 11, which is introduced into the rail head. The soft iron core of the sleeper detection sensor 11 is essentially U-shaped. The magnetic core 11 is guided at a short distance above the rail head in the same longitudinal direction or slides with one leg of the soft iron core directly on the rail head. It is also possible to introduce the magnetic field into the rail head via a running wheel. If no rail fastening is present, the magnetic circuit is closed at the other end of the magnetic core 11, i.e., via the other leg of the soft iron core directly to the rail head of the rail 1.The end of the other leg of the magnetic core is guided approximately over any rail fastenings and, in the exemplary embodiment, carries the Hall sensor 13 on its contact surface with the air gap. The Hall sensor 13 is thus arranged in the magnetic circuit.

[0021] In the area of ​​a sleeper fastening, the magnetic field changes due to additional coupling of the magnetic field 14 via the rail fastening, in particular the sleeper screw 2 or the hook screw 7, to the end of the magnetic core equipped with the Hall sensor 13. The magnetic resistance decreases, the magnetic field increases, and the measured Hall voltage U rises. For reasons of better magnetizability, the magnetic core 11 can be formed from laminations, in particular from several layers of mutually insulated transformer sheet.

[0022] Fig. 4 shows a schematic of the Hall effect sensor 16, which is flooded by the magnetic field B y . A current I flows through the Hall effect sensor, which, transversely to the current, can be tapped at the Hall effect sensor via contacts, generating an electrical voltage U proportional to the magnetic field B y . The following applies to the resulting Hall voltage: U = R H ⋅ I ⋅ B Y d

[0023] As the relationship shows, the resulting voltage U is directly proportional to the current I, a material-specific Hall constant RH, and the magnetic field BY. With increasing thickness d of the Hall layer, the voltage U decreases. Fig. 5shows the mode of operation schematically. The sleeper detection sensor 11 is guided in direction A along the rail 18 at a constant height. The rail 18 is connected via fastening means 17 to sleepers 19 at a sleeper spacing ai. Above this, the curve of the measured Hall voltage U over the track length s is shown. If no fastening means 17 are present, a voltage level 22 is measured. In the area of ​​the metallic rail fastening means 17, the Hall voltage U increases 21. The position of the fastening means 17 and with them the sleepers 19 can now be determined. From the difference between the voltage peaks 21 and the base level 22, a limit value 20 lying between the two values ​​is continuously determined. The mean value of the intersection points of the voltage peak 21 with this limit value 20 gives the position of the fastening means 17 and thus the position of the sleeper 19.

Claims

1. Device for detecting crossties of a track, comprising a crosstie detection sensor (11) which can be arranged on a track-laying machine, optionally on a track measuring wagon associated with the track-laying machine, for measuring and determining the position of crossties (5, 19) on the track, characterised in that the crosstie detection sensor (11) comprises a magnet generating a magnetic field (14, 15) in a magnetic circuit with at least one air gap between the crosstie detection sensor (11) and the track, and a Hall sensor (13) arranged in the magnetic circuit, the Hall voltage (U) of which Hall sensor (13) changing in the longitudinal direction (A, s) of the track serves to determine the position of the crossties (5, 19) in the track.

2. Device according to claim 1, characterised in that the magnet is an electromagnet (12) and / or a permanent magnet.

3. Device according to claim 2, characterised in that a current coil of the electromagnet (12) is connected to a direct current source and generates a direct magnetic field (By) in the magnetic circuit.

4. Device according to claim 2, characterised in that a current coil of the electromagnet (12) is connected to an alternating current source and generates an alternating magnetic field (By) in the magnetic circuit.

5. Device according to one of claims 1 to 4, characterised in that for the detection of metallic components between the crossties (5, 19), several crosstie detection sensors (11) are arranged next to each other in the transverse direction of the track.

6. Device according to one of claims 1 to 5, characterised in that at least one crosstie detection sensor (11) can be displaced in the transverse direction of the track by a displacement device associated with the track-laying machine and / or the track measuring wagon in order to search for metallic components on the track.

7. Device according to one of claims 1 to 6, characterised in that the at least one crosstie detection sensor (11) is arranged on the track-laying machine and / or the track measuring wagon so as to be adjustable in height with respect to the track.

8. Device according to one of claims 1 to 7, characterised in that the Hall sensor (13) is arranged in the air gap.

9. Device according to one of claims 1 to 7, characterised in that a control system continuously determines a limit value (20) (U) from the difference of voltage peaks (21) of the Hall voltage (U) over the track length and a base level (22) of the Hall voltage (U), the limit value (20) lying between the voltage peaks (21) and the base level (22), and determines the position of the crosstie (5, 19) in the track from an average value of the intersection points of each voltage peak (21) with the limit value (20).