|Title of Invention||
WEIGHING DEVICE FOR RAIL VEHICLES
|Abstract||1. Weighing device for rail vehicles having at least one crossbeam (2, 8) serving as a support for a pair of rails (7), and having at least one load measuring device for each rail, wherein each load measuring device is disposed between the relevant rail and the crossbeam, characterized in that the crossbeam is designed as a weighing sleeper (2, 8) in which the load measuring devices (3, 10) are integrated and the weighing sleeper (2, 8) is mounted directly in a ballast track (6) of the rails (7), wherein the ballast track (6) is stabilized at least in the region of the weighing sleeper (2, 8) by ballast bonding.|
|Full Text||FORM 2
THE PATENTS ACT 1970
[39 OF 1970]
THE PATENTS RULES, 2003
[See Section 10; rule 13]
"WEIGHING DEVICE FOR RAIL VEHICLES"
SCHENCK PROCESS GMBH, of Landwehrstrasse 55, D-64293 Darmstadt, Germany,
The following specification particularly describes the invention and the manner in which it is to be performed:
The invention relates to-a weighing device for rail vehicles according to the preamble of claim 1.
Years ago, the weighing of rail vehicles was carried out mostly with the aid of weighbridges, where the total weight of an individual railway wagon was statically determined. In these weighbridges, the rails on the weighbridge were separated from the running rails of the track section by gaps in front of and behind the weighbridge. The weighbridge was mounted on at least four load cells and supported relative to a foundation. Weighbridges therefore had to be as long as a wagon and required a very costly bridge substructure of concrete or steel structural parts.
From EP 0 500 971 Al, however, dynamic weighing methods for rail vehicles are also known, which do not require a costly track substructure. In these methods, the shear strain in the neutral phase of the rail is measured and evaluated. For this purpose, there is welded into the running rail system a weighing rail fitted with strain gauges, of which at least two strain gauges are disposed between the sleepers. The wagon weight is determined in said case by axle-wise addition of the weight signals. As the wheel load however causes deflexion of the rail and of the rail support, the train moves normally in a plane situated under the plane determined by the unloaded rail, while at the same time because of the deflexion of the rails between the sleepers vibrations are generated in a vertical plane. This leads, when weighing a moving train, to variations of the vertical forces and hence to measuring inaccuracies, which are avoidable only by a higher number of measurement points. Such a weighing device may moreover be calibrated only with difficulty because, for this purpose, static
weighing devices are required, which nowadays are mostly to be found only a long distance away.
From DE 44 44 33 7 Al a weighing device for rail vehicles for static and dynamic weight determination is known, in which disposed between the rails and a crossbeam are load cells, by means of which the axle load of an over-travelling railway wagon may be determined. In said case, the rails are each provided with three successively disposed recesses in the rail foot and rail stem, so that the rails were supported in an articulated manner on the force transducers." Because of this articulated support of the two sections of each rail, a costly foundation or a framework construction for take-up of the axle load relative to the ground below is in any case required. What is more, the crossbeams clearly comprise steel H-beams, which cannot be installed in the railway system without major reconstruction work.
The underlying object of the invention is .therefore to provide a weighing device for rail vehicles, which entails only slight structural modifications in the railway system and with which nevertheless a high degree of accuracy is achievable.
This object is achieved by the invention indicated in claim 1. Developments and advantageous embodiments of the invention are indicated in the sub-claims.
Since 1988 it has admittedly already been known, when laying track, to use the ballast bonding technique, whereby with an epoxy resin stabilization of the ballast bed is achieved. In this method, the epoxy resin together with a
hardening agent is sprayed onto the ballast bed and because of its viscosity penetrates therein and bonds the contact surfaces of the ballast stones to one another. During track laying this ballast bonding technique is however used mainly only to protect against flying ballast and for a continuous increase of the stabilization at transition areas between ballasted track and solid track. It is however not known to provide the ballast bonding for supporting a weighbridge.
The invention has the advantage that load measurement by means of weighing sleepers enables both static and dynamic weight measurement of rail vehicles. In particular, it is easy to calibrate such a measuring device also for dynamic weight determination without having to use a weighbridge situated a long distance away.
A particular advantage of this invention is that the entire weighing device comprises only one or more weighing sleepers, which may be installed like other sleepers in the normal ballast track bed. This dispenses with the problems necessarily associated with transporting long track pieces or concrete and/or steel structural parts of the type otherwise required for static weighbridges.
The invention has the added advantage that all of the measuring equipment may be cast in currently used concrete sleepers during the manufacturing process without a large extra outlay. By virtue of weighing sleepers prefabricated in this manner it is then easily possible to assemble variable bridge lengths, comprising e.g. one weighing sleeper for single-axle weighing or eight weighing sleepers
for a three-axle bogie or forty weighing sleepers for complete high-precision weighing of a wagon.
Given the use of such weighing sleepers, the ease of servicing in particular is also advantageous because, if there are defects in the sensor equipment, then, at worst, the whole weighing sleeper has to be exchanged, just like any other track sleeper. However, the load cells in the weighing sleepers may also be designed in such a way that they are individually exchangeable, because they are always installed from above or from the side and are therefore easily accessible.
A further advantage of the invention is that the weighing sleeper is cemented in place in a bonded ballast bed, thereby removing the need for any kind of bridge structure, as is otherwise required with concrete or steel bridges. In particular, given such stabilization of the subsurface, changes in stiffening such as occur with concrete or steel bridges may be avoided because in a defined approach- and departure region there is a continuous increase and decrease respectively of the stiffening, with the result that the track-position-related excitation of disturbing wagon vibrations during the weighing operation is minimized.
In a special development of the invention having shear strain sensors and/or recesses in the rail foot, it is possible' to correct and/or reduce the load shunt effect through the interruption-free stretch of rails. This also at the same time renders rail switches redundant, which are otherwise needed to detect the wagon type during dynamic weighing.
In a further special development of the invention haying load measuring devices with a load feedback facility, it is in particular advantageous that this measuring device may still determine the weight very accurately even when the point of the introduction of force shifts and/or disturbing forces and disturbing torques - of the type customary in railway systems - additionally have to be transmitted.
The invention is described in detail with reference to an embodiment, which is illustrated in the drawings. The drawings show:
Fig. 1: a diagrammatic weighing device comprising two
weighing sleepers and Fig. 2: a detail from a weighing sleeper having a load
measuring device disposed under a'rail.
Fig. 1 of the drawings shows a weighing device for rail vehicles comprising two weighing sleepers 2, 8, which are cemented in place as crossbeams in a bonded ballast bed 6, wherein at the beginning and at the end of the measuring section in each rail a measuring eye 1, 11 is provided as a shear strain sensor for load shunt correction in the region of the space between sleepers.
The two weighing sleepers 2, 8 are disposed in a ballast bed 6, such as is customary as a rail track in railway construction. In this ballast bed 6 the two weighing sleepers 2, 8 are disposed, like other sleepers,
transversely to the direction of travel and parallel and side by side to one another, wherein they are surrounded by the stones forming the ballast bed 6. For consolidation,
the ballast stones are sprayed with a mixed adhesive comprising an epoxy resin base with a hardening agent so that, a bonding of the ballast is produced by the liquid adhesive penetrating into the ballast bed 6. In this case, a bonding of the weighing sleepers 2, 8 with the ballast stones is likewise effected. Hitherto, this ballast bonding has been customary during track laying work in order to protect against flying ballast along high-speed track sections and to achieve stabilization at transition regions between ballast tracks and solid tracks. In many cases, such ballast bonding is also already provided for stabilization at points and track edges in railway stations.
In the region of the weighing device, a ballast bonding has proved advantageous that is effected approximately a wagon-length in front of and a wagon-length after the weighing sleeper or sleepers 2, 8 and, depending on the load, is to be effected up to a depth of 0.5 m. In said case, the ballast stones bond to one another at their contact points or edges, thereby producing a firm, stabilized ballast bed 6. The stabilizing of the ballast bed 6 is in said case dependent upon the quantity and depth of penetration of the mixed adhesive. Different degrees of stabilization of the ballast bed are therefore producible, so that in particular a continuous increase of the stiffening or consolidation at the beginning and/or a continuous decrease at the end of the weighing device is advantageous. In this stabilized ballast bed 6 the weighing sleepers 2, 8 are bonded thereto, so that a force-transmitting connection between the weighing sleepers 2, 8 and the ballast bed 6 also arises.
The weighing sleepers 2, 8 are designed substantially like normal sleepers, with the sole exception that they have the load measuring devices integrated therein. In said case, the weighing sleepers 2, 8, like the other railway sleepers, are preferably made of reinforced concrete and are manufactured by a concrete casting method. The weighing sleepers 2, 8 may however alternatively be made of other materials suitable for the manufacture of sleepers.
The concrete sleepers are provided in the region of the rail support points with recesses 4, 9, in which the load measuring device 3, 10 is installable. The load measuring device 3, 10 may however alternatively be installed in a fixed manner in a prefabricated housing, which is cast integrally in the concrete sleepers. At the same time, cable ducts 25 for running the cabling of the measuring device are provided in the weighing sleepers 2, 8. These cable ducts 25 are. preferably provided from the recesses 4, 9 of the load measuring 'device 3, 10 to the centre of the sleeper, where they terminate in a further recess 24, in which the interconnection is effected. It is however also possible for electronic circuits for measured-value processing and the supply of power to be simultaneously accommodated in this recess 24. This interconnection recess 24 of each weighing sleeper 2, 8 is connected to the other weighing sleepers by a connecting channel 5, which runs these devices to a central evaluation device 12.
The load measuring devices 4, 10 provided in the recesses 4, 9 are provided at their upper side with connection
elements, which establish a fixed connection to the rail 7 situated above. Preferably, clamping connections 15, 14 of the type also used to connect the rails .7 to the remaining
sleepers are provided for this purpose. However, other connection elements may alternatively be provided, should this be necessary or advantageous owing to the design of the load measuring device 3, 10.
The rails 7 are designed free.of interruption in the region of the weighing device and are conventional running rails. The entire weighing device is preferably formed by six to eight weighing sleepers 2, 8, which are suitable for weighing railway wagons or other rolling stock having up to three-axle bogies and comprise a measuring section of 4 to 5 m. In the described embodiment, however, for the sake of Clarity only two weighing sleepers 2, 8 are illustrated. To determine the weight of rail vehicles having only two axles, weighing devices comprising only one weighing sleeper 2, 8 would however also be sufficient. Given special accuracy requirements and for effecting static weighing of complete railway wagons, weighing devices comprising forty weighing sleepers 2, 8 and a measuring section of 25 m may also be provided.
For correction of the load shunt effect, at the beginning and/or at the end of the measuring section midway between the first and/or last weighing sleeper 2, 8 and the adjacent sleeper a so-called measuring eye 11 is provided as a shear strain sensor in the neutral axis of each rail 7. With such a measuring eye 11 it is easy to measure the shear strain that arises during overtravel of a vehicle axle in the neutral axis of each rail -7. In the present case, such measuring eyes 11 have proved advantageous because they are designed as a circular sensor unit having strain gauges. These measuring eyes 11 are advantageously easy to fasten in a'bore in the neutral axis of each rail.
Such shear strain sensors 11 may however alternatively be of a different design, e.g. they may alternatively be fitted directly on the rail stem.
These shear strain sensors 11 detect a load during overtravel of the axle of a rail vehicle in accordance with the load shunt effect, which corrupts the weighing result measured by the load measuring devices 3, 10 in the weighing sleepers 2, 8. This corruption by the load shunt effect is all the greater, the stronger this coupling to the load measuring device 3, 10 is. If only one weighing sleeper 2, 8 is provided, then a relatively large load shunt error occurs. In the case of a weighing device comprising a plurality of weighing sleepers 2, 8, this load shunt error is correspondingly reduced.
By virtue of the previously described determination of the
shear strain this error may however be corrected by
suitable calibration. For this, the signals of both the
shear strain sensors 11, 1 and the load measuring devices
3, 10 of each weighing sleeper 2, 8 are supplied to a
central evaluation device 12. With the aid of one or more
known reference masses or reference dynamic effects (e.g.
by means of a test instrument) the weighing device may
first be statically calibrated. In said case, the
detection of the location-dependent load shunt effect is
also effected by means of the shear strain sensors 1, 11.
For this purpose, a reference mass or the test instrument
is mounted at various positions of the measuring section.
Alternatively, this operation may be carried out in an
automated manner with a moving reference mass. The
correction functions derived from the shear strain
measurements of the calibration operation are stored in the
central evaluation device 12. Subsequently, for unknown masses the static weights may be determined. With these weights, in turn, the weighing device may be dynamically calibrated. The dynamic correction functions thus determined are likewise stored in the central evaluation device 12. It is therefore easily possible to effect static and dynamic calibration of such a weighing device with known reference masses or a test instrument, as well as further unknown masses. The thus calibrated weighing signal in the central evaluation device 12 may be interrogated or displayed at its output for further processing or for display by a further device.
The load shunt effect is however also reducible by means of a recess in the rail foot and rail stem to such an extent that its influence on the measurement result is only negligible. For this purpose, in front of the first weighing sleeper 8 a recess is incorporated in the rail foot and rail stem, which however does not interrupt the overtravel part, so that an articulated coupling is
produced. In said case, the load shunt effect is all the lower, the further this joint lies in a bearing-free manner from the first measuring sleeper 8 and the less bending stress is transmitted by the joint. Since in this joint, however, a specific shear strain may not be exceeded in order to avoid damage during overtravel with a permissible load, it is impossible to avoid a. specific load shunt effect. It has therefore proved particularly advantageous additionally to provide a recess for measuring the shear strain in each rail so that, particularly in the case of small overtravel loads, it is still possible to achieve accurate dynamic weighing with a minimum bridge length. In said case, the measurement result may in particular be
further improved in that both at the beginning and at the end of the measuring section a recess and a shear strain measurement is effected.
The shear strain sensors 1, 11 are used simultaneously as , rail switches. For this purpose, with the aid of defined distances between axles of known rail vehicles in each case the beginning and the end of an overtravelling vehicle is determined by the central evaluation device 12. From the known and measured distances between axles the vehicle weight is then determinable in the evaluation device 12.
In Fig. 2 of the drawings a load measuring device 3 is illustrated in detail in the form of a sectional drawing of a detail of a weighing sleeper 2. Here, the same reference characters have been used as were used for functionally identical parts of Fig. 1 of the drawings. The weighing sleeper 2 in said case contains a load measuring device 3, which is disposed in a fixed manner in an integrally cast housing 22. This housing unit 22 advantageously contains reinforcing elements 23, which guarantee a permanent connection to the reinforced concrete sleeper 2. In this housing part 22 a load measuring device 3 is provided as a load cell, which is disposed below the rail 7. This load cell 3 contains a load introduction part 18, a deformation body 17 with strain gauges 20 fitted thereon and a load output part 21 fastened in a fixed manner to the housing 22. This load cell 3 is of an S-shaped design so that the load introduction parts 18 and the load output parts 21 are simultaneously designed as load feedback elements. In said case, the load introduction element 18 and the load output element 21 are separated by horizontal slots 16, 26 from the deformation part 17. The deformation part 17 contains
in the centre two oppositely directed horizontal blind holes 19, so that between both bores a vertical deformation area remains, to which the strain gauges 2 0 are fitted. These generate a signal proportional to the weight on the rail 7.
On the load introduction part 18 webs having clamping elements 14 are provided, between which the rail 7 extends transversely to the load cell 3 and is firmly screw- connected thereto. In this case, load cells 3 with load
feedback elements 18, 21 are advantageously provided since, ( with these, the measured load is substantially independent of the load introduction location, so that shifts of the centre of gravity along the rail 7 have no influence on the measurement result. For this reason, balance beams with load feedback elements are also advantageously usable, in which case the rail 7 would be fastened to an upper load feedback element, while a bottom load feedback element would be firmly connected to the housing 22.
The load measuring devices 3, 10 may also be designed in such a way that they are fastened to the housing 22 by a detachable connection. In particular, screw connections may advantageously be provided for this purpose, so that the individual measuring devices 3, 10 in the event of damage may be individually exchanged from above after lifting of the rail 7. The housing 22 of the load measuring devices 3, 10 might also be moved right up to the sleeper end and provided with a detachable side part, so that the load measuring devices 3, 10 might also advantageously be exchanged laterally, without having to lift the rail 7.
In longitudinal direction of the weighing sleeper 2 a horizontal cable duct 25 is provided, in which the wiring to the strain gauges 2 0 and the measuring eyes 1, 11 extends so as to be protected from damage. The cable duct 25 terminates in the middle of the weighing sleeper 2, 8 in an interconnection recess 24, which additionally contains electric circuits, which are used for excitation and for distance-independent measurement signal conversion (A/D converter).
Provided in rail direction above the interconnection recess 24 is a tubular connection channel 5, by means of which the weighing sleepers 2, 8 are electrically connected to one another and to a central evaluation device 12.
1. Weighing device for rail vehicles having at least one crossbeam (2, 8) serving as a support for a pair of rails (7), and having at least one load measuring device for each rail, wherein each load measuring device is disposed between the relevant rail and the crossbeam, characterized in that the crossbeam is designed as a weighing sleeper (2, 8) in which the load measuring devices (3, 10) are integrated and the weighing sleeper (2, 8) is mounted directly in a ballast track (6) of the rails (7), wherein the ballast track (6) is stabilized at least in the region of the weighing sleeper (2, 8) by ballast bonding.
2. Weighing device as claimed in claim 1, wherein the weighing device comprises at least one weighing sleeper (2, 8) or a plurality of weighing sleepers (2, 8).
3. Weighing device as claimed in claim 1 or 2, wherein the weighing sleeper (2, 8) is made of reinforced concrete or of another material provided for the manufacture of sleepers.
4. Weighing device as claimed in any one of the preceding claims, wherein each weighing sleeper (2, 8) contains at least two recesses (4, 9) for integration of the load measuring devices (3, 10), which are provided underneath the rail bearing arrangement.
5. Weighing device as claimed in any one of the preceding claims,
wherein disposed in the recesses (2, 9), are load measuring devices (3,
10) of which the load introduction part (18) is connected to the rail (7)
and the load output part (21) is connected in a force-and torque-
transmitting manner to the sleeper (2, 8).
6. Weighing device as claimed in any one of the preceding claims,
wherein the load measuring device (3, 10) is fastened in a fixed
housing part (22), which is cast with the sleeper (2, 8) or is firmly
connected thereto by other connection means.
7. Weighing device as claimed in any one of the preceding claims, wherein the load measuring device (3, 10) is connected by a detachable connection to the housing part (22), wherein the housing part (22) has an upper or laterally removable closure part, by means of which the load measuring device (3, 10) is exchangeable.
8. Weighing device as claimed in any one of the preceding claims, wherein the load measuring device (3, 10) is designed as a load cell with load feedback elements (18, 21).
9. Weighing device as claimed in any one of the preceding claims, wherein the weighing signals of the load measuring devices (3, 10) of each weighing sleeper (2, 8) are combined with one another, so that from the measurement signals the weight of the rail vehicles or parts thereof are determinable.
10. Weighing device as claimed in any one of the preceding claims,
wherein in front of the first weighing sleeper (8) there is disposed in at
least one rail (7) at least one shear strain sensor (11), the
measurement signals of which are used to correct the load shunt
effect and/or as rail switches.
11. Weighing device as claimed in any one of the preceding claims, wherein at least in front of the first or in front of the first and after the last weighing sleeper (2, 8) a shear strain sensor (1, 11) is provided, wherein the shear strain sensor (1, 11) is disposed in the neutral phase of the rail (7).
12. Weighing device as claimed in ay one of the preceding claims, wherein on the basis of the shear strain measurement and a static calibration in a central evaluation device (12) a location-dependent correction function is generated and stored, which during dynamic weighing is used to take the load shunt effect into account.
13. Weighing device as claimed in any one of the preceding claims, wherein on the basis of the shear strain signal in the central evaluation device (12) and with the aid of defined distances between axles the beginning and end of a wagon or the beginning and end of a bogie are determined.
Weighing device as claimed in one of the claims 10 to 13, wherem the shear strain sensor (1, 11) is designed as a measuring eye, which is disposed in a bore of the rail or is formed by directly fitted strain gauges.
Weighing device as claimed in any one of the preceding claims, wherein at least in front of the first weighing sleeper (8) there is provided in the rail foot a vertical or obliquely downwardly open recess, which connects the running rail (7) in an articulated manner to the weighing sleeper or sleepers (2, 8).
Weighing device as claimed in claim 15, wherein at least in front of the first and/or after the last weighing sleeper (2, 8) there is provided in the rail foot a vertical or obliquely downwardly open recess, which connects the running rail (7) in an articulated manner to the weighing sleeper or sleepers (2, 8).
Weighing device as claimed in any one of the claims 1 to 16, wherein the ballast bonding is provided in the direction of travel at a specific distance in front of the first or in front of the first and after the last weighing sleeper (2, 8).
Weighing device as claimed in claim 17, wherein the weighing sleepers (2, 8) are bonded to the ballast bed (6).
19. Weighing device as claimed in any one of the preceding claims, wherein the stabilization by means of the ballast bonding is provided in dependence upon the rated load of the weighing sleepers (2, 8) and/or the permissible speed of travel.
20. Weighing device as claimed in any one of the preceding claims, wherein the ballast bonding is provided in the approach region in front of the first weighing sleeper (8) with continuously increasing stiffening and/or in the departure region after the last weighing sleeper (2) with continuously decreasing stiffening.
Dated this 26th day of June, 2001.
OF REMFRY & SAGAR
ATTORNEY FOR THE APPLICANTS
|Indian Patent Application Number||IN/PCT/2001/00767/MUM|
|PG Journal Number||25/2007|
|Date of Filing||26-Jun-2001|
|Name of Patentee||SCHENCK PROCESS GMBH|
|Applicant Address||LANDWEHRSTRASSE 55, D-64293 DARMSTADT, GERMANY|
|PCT International Classification Number||G 01 G 19/04|
|PCT International Application Number||PCT/EP99/09994|
|PCT International Filing date||1999-12-16|