Apparatus for continuously measuring the position of a moving rail vehicle

A measuring stretch along a railway track of a transloading system has an array of switches with respective sensors positioned for engagement by a wheel of a railway carriage. The lateral displacement of the railway carriage wheel is prevented by a guide disposed along the rail at the level of the head at a distance of 30 to 50 mm from the head of the rail. The row of switches can be provided on the opposite side of this rail. The switches synchronize a transloader with the rail vehicle via a computer to which the switches are operatively connected.

FIELD OF THE INVENTION 
My present invention relates to an apparatus or device for continuously 
measuring the instantaneous position of a rail vehicle traveling along a 
railway track having a pair of parallel rails and a measuring stretch 
parallel to the track along which measurement of the position of the 
vehicle is to occur. In particular, the invention relates to a measurement 
stretch which can provide an input for a computer which can be used to 
control a load transfer system, i.e. the drive for a transloader or the 
like for transferring loads from the railway vehicle to an off-loading 
vehicle or station or for transferring loads from a station alongside the 
track to a rail vehicle on the track. 
BACKGROUND OF THE INVENTION 
In transloading systems, load units like containers, replacement 
containers, trailers, semitrailers or the like, are exchanged between rail 
vehicles and a storage station or another vehicle alongside the track 
utilizing a transloader, e.g. a portal crane, which is also displaced 
along the track and thus must be synchronized with the rail vehicle or 
positioned in accordance with the position of the traveling rail vehicle. 
It is thus important to determine the instantaneous position of the rail 
vehicle so as to coordinate the movement of the transloader with the 
movement of the rail vehicle. In loading or transferring a load unit onto 
the load vehicle such synchronization is important so that the load unit 
is lowered onto the proper position of the railway car whereas for 
unloading the proper synchronization is required to ensure exact alignment 
of the transloader with the load unit on the railroad car to enable it to 
be picked up from the car. For that purpose, precision determination of 
the position and the speed of the railway vehicle is necessary. 
For such determination in the past, measuring carriages have been used, 
e.g. as described in DE 42 33 007 A1. Systems of that type are very costly 
and complex. There is also a problem with reliability and breakdown. 
OBJECTS OF THE INVENTION 
It is the principal object of the present invention to provide an improved 
device for continuously measuring the instantaneous position of a rail 
vehicle traveling along a measurement stretch and which is capable of 
reliably supplying a measurement result, i.e. registering the position of 
the vehicle, at comparatively low cost. 
Another object of the invention is to provide a system for the purposes 
described which is less prone to failure and hence is more reliable than 
prior art systems. 
Another object of this invention is to provide a improved transloading 
system in which the determination of the position of a traveling rail 
vehicle is facilitated. 
SUMMARY OF THE INVENTION 
These objects and others which will become apparent hereinafter are 
attained in accordance with the invention by providing along the 
measurement stretch over the length thereof, spaced apart or distributed 
switching elements which are provided with mechanical sensors responsive 
to engagement by the vehicle and thus disposed in the region of a rail of 
a railroad track, for example so that the sensors are successively engaged 
by a wheel of the rail vehicle. 
In addition, proximal to one of the rails on the flange side thereof, i.e. 
on the side at which the wheels of the vehicle have their respective 
flanges, a guide is provided over the total length of the measurement 
stretch and whose distance from the head of the rail amounts to 30 to 50 
mm. 
With this system, the position of a wheel of the vehicle is detected by the 
measurement sensors and the respective switch elements are actuated to 
signal the position of the vehicle to a computer which can control the 
transloader in the sense described previously. The drive for the 
transloader can be so controlled that the transloader can always be 
positioned with high accuracy at the correct location with reference to 
the vehicle and synchronously moved therewith. 
The guide rail or bar alongside the head of one of the rails on the flange 
side thereof also ensures that the wheel which engages the sensors will 
always track along an ideal line relative to the sensors and hence even 
during a tendency toward sinusoidal travel or with wear of the wheel, the 
sensors will be properly engaged one after the other. 
The sensors can be tabs which project into the path of the felly of the 
wheel and can extend for a sufficient width so that, as long as the wheel 
flange lies between the head and the guide, the felly will engage the tabs 
which actuate the switch elements. Thus the position of the vehicle is 
always reliably determined. 
A device according to the invention for measuring the position of a 
traveling rail vehicle can thus comprise: 
a row of switching elements distributed along the stretch and provided with 
mechanical sensors positioned for engagement by the vehicle for successive 
operation of the switching elements as the vehicle travels along the 
stretch of track; 
a guide extending over the length of the stretch alongside the one of the 
rails and at a spacing from the flank of 30 to 50 mm for limiting movement 
of the vehicle away from the sensors as the vehicle travels along the 
stretch; and 
a computer operatively connected with the switching elements for signaling 
the position of the vehicle along the track. 
A transloading system according to the invention can comprise: 
a track formed with a pair of rails extending through a transloading 
region; 
a railway vehicle traveling along the track and displaceable along a 
stretch of the track along which a position of the vehicle is to be 
measured, the vehicle being capable of receiving a load to be transferred 
from the vehicle or transferred to the vehicle, the vehicle having wheels 
each formed with a felly riding on a respective one of the rails and a 
flange adjacent the felly and disposed along a flank of the one of the 
rails; 
load-receiving means adjacent the track and adapted to receive a load from 
or deliver a load to the vehicle; 
a transloader at the region bridging the track and the load-receiving means 
for picking up a load from the vehicle and depositing it upon the 
loads-receiving means and for picking up a load from the load-receiving 
means and depositing it upon the vehicle; 
a device for continuously measuring a position of the vehicle along the 
stretch, the device comprising: 
a row of switching elements distributed along the stretch and provided with 
mechanical sensors positioned for engagement by the vehicle for successive 
operation of the switching elements as the vehicle travels along the 
stretch of track, and 
a guide extending over the length of the stretch alongside the one of the 
rails and at a spacing from the flank of 30 to 50 mm for limiting movement 
of the vehicle away from the sensors as the vehicle travels along the 
stretch; and 
a computer operatively connected with the switching elements for signaling 
the position of the vehicle along the track and controlling the 
transloader. 
Preferably the switching elements are provided directly proximal to the 
rail with the switching elements being located adjacent the rail head or 
above or below the rail head so that damage to the switching elements is 
excluded. Further protection of the switching elements against damage can 
be provided by a sheet metal covering which lies above the array of switch 
elements. 
According to a further feature of the invention, the sensors which are 
engaged by one of the wheels of the vehicle are switching tabs of a 
mechanically actuatable array of switches, thereby enabling the use of 
commercially available components. 
It has been found to be advantageous to spring mount the switch elements 
for the switching tabs or to make them resilient in themselves. The spring 
mounting can be effected by metal springs, rubber springs or the like or 
by means of pneumatic or hydraulic units. Each switch element or its 
respective switch tab can be individually mounted or groups of switch 
elements or groups of switch tabs can be assembled together and spring 
mounted together. 
In a preferred embodiment of the invention, the spacing of the guide from 
the head of the rail is 35 to 40 mm. This enables the use of small and 
thus inexpensive switch elements with relatively small actuation 
displacements. Preferably the guide is disposed alongside the same rail as 
is provided with the array of switch elements but on the opposite side 
thereof. 
To facilitate transport and mounting of the guide rail, it may be composed 
of a plurality of aligned guide rail segments which, because of their 
reduced weight can be more easily handled than a guide rail extending the 
full length of the stretch.

SPECIFIC DESCRIPTION 
As can be seen from FIG. 1, an array of switching elements which may be 
spring-mounted as represented at 20 can have their respective actuating 
tabs or sensors 1.2 spring-loaded via the actuating formation 21 of the 
switch which may be spring-biased upwardly by the conventional spring 
within the mechanical switch. The tabs 1.2 are themselves resilient by 
virtue of a bend 22 therein and a bent finger 23 which is engaged by the 
felly 24 of a railroad wheel 3 whose flange is represented at 25 in FIG. 
4. A cover sheet metal element 26 overlies switches 1 and has a downwardly 
turned formation 27 which engages in the bend 22 but does not contact the 
tab 1.2. The array of switch elements lies below but proximal to the head 
28 of a rail 4 whose web 29 extends upwardly from the base 30 which can be 
mounted on sleepers or the like as represented at 31. The head 28 has a 
pair of flanks 32 and 33. The tabs 1.2 lie along one side of the head 28 
while a guide rail 12 lies along the opposite side at a spacing A from the 
flank 33. The rail 12 can be subdivided into segments 12a, 12b, etc. in 
end to end relationship (see FIG. 2), the segments being mounted on spaced 
apart supports 34 via bolts 35 as is visible in FIG. 2. The switch 
elements 1 can be simple switches as shown at 35 in FIG. 3 connected 
between a source 36 of electric current with a computer 37 which operates 
the transloader controller or drive 38. 
Returning to FIG. 2, it can be seen that the tabs 1.2 can be formed as 
projections from a sheet metal member 39 which is held in place by bolts 
40 and nuts 41. 
The distance A is preferably 35 to 40 mm but can be as great as 30 to 50 
mm. 
As can be seen from FIG. 4, a measuring stretch 42 can be provided in 
transloading system 43 and can have the sensors 1.2 spaced all along this 
measuring stretch on one side of the rail 4 while on the opposite side of 
this rail, the guide 12 is mounted. The guide is thus at the flange side 
of the rail and limits the displacement laterally of the wheel 3 of a 
train 44 of cars 45 which carry load units 46, the latter being 
containers, trailers or semitrailers. The transloader in this case is a 
portal crane 47 which is displaceable along the tracks 48 and 49 by a 
drive not shown operated by the controller 38, the portal crane carrying a 
load engaging spreader 50 which can deposit the load unit on another 
railway vehicle 51, on a truck or on a storage location as represented by 
the region 52 here, for convenience, being shown as another railway track 
53. The operation of the transloader, of course, is clear. 
By ascertaining the position and speed of the train 44, the computer 37 
synchronizes the transloader 47 therewith to allow transfer of the load 
units to the train or from the train. 
Since the rail 12 allows a shift of the wheel 3 in its sinusoidal travel to 
the region represented between the solid lines and broken lines in FIG. 1, 
excluding movement into the dot-dash line position, for example, the wheel 
3 always engages the row of sensors 1.2 to operate the switches 1, 35 to 
thereby signal the position of the train to the computer 37.