Note: Descriptions are shown in the official language in which they were submitted.
1
RAIL VEHICLE HAVING A DEVICE FOR PEDESTRIAN PROTECTION AS WELL AS A
DEVICE FOR PEDESTRIAN PROTECTION
The invention relates to a rail vehicle having a device for pedestrian
protection in the event of a
collision with the front of the vehicle as well as a device for pedestrian
protection for application
in rail vehicles.
Rail vehicles, such as, for example, low or middle-level floor street cars,
generally operate in
mixed traffic. This means that they are participants in public traffic and as
such interact with
people as users of the roadways.
The running over of people who are located directly in front of the vehicle
has always
represented a problem, inasmuch as the metal to metal pairing of the passenger-
conveying rail
vehicle wheels to the rails, combined with the high vehicle mass means that a
longer stopping
distance is required to come to a full stop than, for example, with
automobiles, which both
weigh less and, through the pairing of rubber to asphalt between the wheel and
roadway, have
a higher degree of friction..
The problem of running over people occurs in multiple areas. On the one hand,
there is
already a significant danger of injury through the "drawing in" under the
vehicle of the person
into the gap at the front of the vehicle. Furthermore, it is almost impossible
to avoid injuries
when running over a person or a part of person who might be drawn in by the
wheels. On top
of this, an open coupling area of the vehicle holds an additional high risk of
injury. In the event
that a rail vehicle comes to a standstill, before a person who has already
fallen under the
vehicle reaches the danger area of the wheels, it is possible to reduce life-
threatening injuries
to a maximum, even if one can never completely preclude them.
Protection systems that fall under the concept of "obstacle deflector" have
been known since
the very start of the rail vehicle history and have been produced in the most
wide-ranging of
forms. Known devices or solutions in the area of obstacle deflectors work on
the basis of a
minimization of the risk of injury in cases of persons being drawn into the
gap on the front of the
vehicle between the underbody and roadway or being run over.
In the area of purely mechanical deflecting protection systems and devices,
the focus has lied
and continues to lie in the minimization of injury to persons, to the greatest
extent possible,
through measures that will limit or prevent the drawing in of persons who have
already been
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partially run over in the area between the wheels and the rails. The basic
concept of these
systems is that of distancing people from the direct proximity of the danger
area until such time
as the vehicle has not come to a complete standstill. In this, the gap between
the underbody of
the vehicle and the roadway at the front of the vehicle plays a decisive role.
If the gap is
sufficiently narrow, one should be able to avoid that one even arrives at a
point where a person
can be drawn under the vehicle.
The conditions of use of the vehicles do however stipulate geometric
requirements for this gap:
assured available ground clearance when approaching vertical radii (crests and
troughs) in
conjunction with the kinematic circumstances of the distance of the running
gear to the front
overhang. Many solutions for the protection of people that have been realized
foresee a
barrier of a size that corresponds, for example, to that of a person lying in
front of the vehicle
and that meets precisely at the start of the gap of the structure hanging at
the front of the
vehicle. This structure is constructed in such a manner that it can push
obstacles up to a
certain size in front of it without damage. In the event in which an obstacle
is such that, due to
is overly large size or because of too much friction against the direction of
travel, it cannot be
pushed further ahead, this structure allows for a further structure to be
folded down from the
underbody to the roadway, before there is a risk of the first reaching its
breaking point. This
second downward folding structure forms a "ramp" immediately in front of the
first rolling gear,
in such a way that, in the case in which the obstacle were to break through
the first structure,
there is still the possibility that a "pick-up" can occur in front of the
danger area. Such a system
is widely known through its use in, for example, high floor street cars, for
example of the
"DUEWAG" brand since the 1960's.
These systems do however only find sensible application when the vehicle has a
sufficiently
large ground clearance, which could reasonably turn away an obstacle the size
of run-over
person before the danger area, without the run-over person have already
previously suffered
major injury.
A disadvantage of this protection system is that the majority of vehicle types
which employ it
are high or middle-level floor vehicles, which are generally laid out with
appropriate ground
clearance.
A further disadvantage is that sharp-edged deformations or breakages can occur
to the
protective structures that are present when the same are not able to support
the burden of the
person "to be pushed".
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Other purely mechanical solutions for run-over protection, which can be
employed in the field
of lower-level floor vehicles, operate in a manner similar to the principle
described above for
middle-level and high floor vehicles; however, with the difference that the
first protection
structure is not implemented in a weight-bearing manner. Furthermore, these
first structures
or brackets are also set at a significant distance to the front of the
vehicle. This means that, on
the one hand, a run-over person must already have ended up quite far under the
vehicle before
they come into contact with the first structure. On the other hand, this
structure is not set up so
as to push the person further along in front of it, but rather only to allow
the final "catching
structure" be folded down.
The use of airbags in a protection system for persons found in front of the
vehicle has already
been described by the rail-vehicle industry, however until now it has still
only been
implemented in a restrained manner ¨ mainly based upon the argument whereby a
protection
system that exists exclusively of an airbag application cannot be returned to
its initial state after
the deployment of the airbag. Such a solution is, for example, described
amongst others in DE
102013204555 Al.
A further difficulty is represented by the design of these airbags, which are
meant to ensure
protection against the running over or drawing in under the vehicle in the
area of the gap
between the underbody at the front of the vehicle and the roadway.
Known airbag technologies go limp after deployment through a drop in pressure.
This brings
along the problem of stability of the shape ¨ the airbag should, subsequent to
its deployment,
in its inflated condition be able to retain its stability of shape at least
until such time that the
vehicle has not come to a full standstill.
So-called "soft-Noses" represent relatively widely used systems for the
protection of persons
found in front of vehicles. In this case, a soft dampening coating, for
example, a polyurethane
(PU) containing synthetic material, is applied to the frontmost contour of the
vehicle so as to
allow for a maximum dampening of any impact of a colliding person with the
vehicle. These
systems do however not offer any protection against the drawing in or running
over of persons
under the vehicle. This type of solution is, for example, known from its use
in the "Hermelijn"
lower-level floor street cars of the "De Lljn" operator in the Belgian cities
of Ghent and Antwerp.
The vehicle manufacturers are furthermore already attempting to maintain the
opening on the
front of the vehicle between the underbody and the roadway as small as
possible so as to
prevent, to the greatest extent possible, the drawing in of persons under the
vehicle. In this
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case there is, however, not only the conflict between the minimum ground
clearance set forth
by the operators, but rather also the kinematic boundary conditions in
operational conditions, in
particular, the so-called "trough trajectories". In these circumstances, the
vehicle travels
through a vertical radius with an increasing gradient ("trough" as opposed to
"crests"), which
reduces the free vertical distance of the foremost point of the vehicle to the
roadway to the
minimum. This effect is dependent on the kinematic relationships between the
distances of the
foremost point of the vehicle to the point of rotation of the first running
gear in combination with
the distance of this point of rotation to the point of rotation of the next
running gear or railcar
connector.
The majority of protection devices that have been implemented up until today,
which are
intended to prevent the running over of persons, are aimed at repulsing and
thereby keeping
the person away from the direct danger area, the contact area of wheel and
rail. These
deflector systems that are generally multi-phase (for example DE 102013204555
Al) only first
initiate the protection mechanism when the deflector mechanism is triggered
through a
physical contact with the obstacle being run over in the frontal area of the
vehicle.. This does
however presuppose the partial running over of a person by the vehicle. An
advantage
however of the purely mechanical systems is, however, their immediate and
simple ability to be
re-initialized subsequent to an occurred application insofar as no function-
impairing damage
has occurred to the system.
Further known solutions are made up of a deflector structure that is located
immediately
behind the front side of the vehicle and is set forth as a "mini-railcar" on
its own rolling stock
which is permanently activated by means of a shear-resistant connection to the
underbody.
This structure is affixed in a shear-resistant but height-variable manner to
the underbody and
can therefore offset differences in height that the front unit is subject to
during travel, and it
features a constant distance to the roadway through its own rolling stock. The
disadvantage of
this solution is that, in the case of varying weather conditions such as snow
and ice, as well as
with sand and stones, the "mini-railcar" is affected and this represents more
of an obstacle to
operation. Such devices are, for example, fitted to street cars in Seville or
Zaragoza.
The purpose of the invention is to present a rail vehicle with a device which
allows for the
complete "deflection" of persons who are found to be in front of the vehicle
from the danger
area. The objective thereof is to completely avoid the running over of passers-
by.
This purpose is achieved according to the features of Claims 1 and 13 of the
invention. For this
purpose, the invention comprises a rail vehicle with a device or a device on
its own, which is
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made up of an arrangement of one or multiple inflatable structures in the area
under the frontal
covering, which are inflatable by means of a gas medium. It is advantageously
foreseen that
the actual structure can form not only an open body, but also a closed body.
It is furthermore
advantageous if the constituent material of the structures, beyond other
materials that are
used, can be made of metallic materials. It is likewise advantageous, when
metallic materials
are used, when it is foreseen that the structure comprises a flexible welded
double blank that is
inflatable with a gas medium by means of a feed line or by a gas generator
that is directly
connected to the structure by internal pressure reshaping. In further
optimization steps, the
metal structure can be modified through the choice of the wall thickness or
through substitution
with other flexible metal structures.
Hereinafter, the invention describes a selected embodiment of the inflatable
structure as a
closed welded metallic double blank with minimal wall thickness. This choice
does, however,
only represent one of the multiple combinations of the invention, and is not
exclusively limited
to this choice. So as to achieve a high degree of compliance to bending with a
high resistance
to tearing, a special metallic membrane material should be employed which is
primarily made
up of a fine metallic mesh.
It is advantageous when the structure features flexible inflatable tear-
resistant and contact
resistant properties. The structure can be composed of a metallic membrane
material, which
features a wire-mesh structure, wherein the wire-mesh structure can feature
one or multiple
layers. It is particularly advantageous when the wire-mesh structure features
internal and/or
external protection layers made up of elastic materials. For the control of
the pressure profile,
the inside of the structure is laminated with an elastic foil, which minimizes
or totally prevents
the escape of gas. In the case of very fine-meshed reticulation, it is
possible to also omit this
internal film in accordance with the required pressure decrease
specifications. So as to further
improve the resistance to tearing, it is also possible to fully or partially
apply additional
protective film on the outer skin.
The inflation of the metal structure is triggered by sensor technology
according to a further
particular feature, which is located on the front of the vehicle. It is
advantageous when the
sensor technology is fitted with means of measurement which can recognize
and/or detect a
frontal impact of a person against the front of the vehicle. It is foreseen,
according to a
particular feature, that the metal structure forms a geometrically adaptive
molded form in
activated state, which fills out the hollow space between the underbody of the
vehicle and the
railway. The inflation of the metal structure therefore advantageously occurs
with a
corresponding expansion speed which prevents the drawing in of a person under
the vehicle.
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The invention thereby advantageously combines the basic principle of complete
"deflection" of
persons ending up in front of the vehicle, from the danger area through the
use of a closed
metallic structure which is activated through inflation. The teaching
furthermore is based upon
interplay of the electromechanical-pneumatic. The invention thereby prevents
both the
drawing in/running over of a person who has unexpectedly come to be lying in
the roadway
immediately in front of the vehicle in the nominal gap on the front of the
vehicle, as well as
every other further danger of a run-over by the track wheels. Following
activation, the metal
structure can remain underneath the vehicle, inasmuch as it adapts to the
varying ground
clearance.
The present invention can be integrated into all rail vehicles with front
covering. It is, in
principle, irrelevant whether one is dealing with a high, middle or low-level
floor vehicle. The
protection system in accordance with the invention can be installed in all
modern rail vehicles
and can be retrofitted to all rail vehicles that are now in use.
Inasmuch as the features of the device that are described in Claim 13 and the
corresponding
dependent claims already follow from the description here above, a particular
description of the
device will be omitted to avoid repetition.
The invention will hereinafter be more closely described on the basis of the
embodiment
examples that are represented in the illustrations. The illustrations show:
Fig. la: a rail vehicle in side view with a person in the frontal area,
Fig. lb: a rail vehicle in front view with a person in the frontal area,
Fig. 2a: a rail vehicle in side view with a device for the protection of
passers-by,
Fig. 2h: a rail vehicle in front view with a device for the protection of
passers-by,
Fig. 3a: a rail vehicle in side view with a device for the protection of
passers-by in
activated state,
Fig. 3b: a rail vehicle in front view with a device for the protection of
passers-by in
activated state,
Fig. 4a - c: a representation of the principle of the mode of action of a
device for the
protection of passers-by,
Fig. 5a - 5c the schematic construction of the inflatable structure, in
Fig. 5b with solely a
one-layer construction (5b) and with an additional optional tear-away
protective
layer (5c),
Fig. 6a - c schematic representation of various lay-out types or forms of
the structure.
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In rail traffic, in particular in inner-city, street-car traffic, accidents
between a rail vehicle 1 and
persons (pedestrians) 2 are not a rarity. The same can bring about serious and
deadly injuries,
in particular in the event of a front impact, when the person 2 ends up in the
hollow area
between the rail vehicle 1 and the ground following the impact. The device 4
is made up of at
least one structure 7 that is inflatable by means of a gas medium 6 that will
remain in a stable
form until such time that the vehicle can be brought to a standstill.
The risk of injury will be significantly reduced through the device according
to the invention,
inasmuch as the hollow space between the rail vehicle 1 and the ground 3 will
be filled
immediately before or after the collision by means of the device 4 that is
fitted on the underside
of the front of the rail vehicle, such that the person 2 involved in the
collision is not able to end
up under the rail vehicle 1 and preferably will deflected next to the vehicle
rails. Injuries are not
to be herewith precluded; the same should however be substantially more
limited and occur
without threats to life. (See Fig. 1 and 2)
A selection of structural materials of the device according to the invention
which is based upon
a structure 7, marked as a metallic structure, namely a thin-sheet metal
structure, which can be
expanded or inflated through a gas medium 6 that is fed in through lead lines
11 (various states
of inflation 8, 9, Fig. 3 and 4). The structure can also be directly connected
with a gas
generator (not depicted).
It is advantageous if the flexibility of the metal structure is adjustable
through the wall thickness
and if this structure can exist as a "Tailored Blank" in the shape of a welded
double blank, even
if more supple metallic materials are imaginable. The arrangement in the
initial position prior to
activation of a detection technology (which is not included in this invention)
is thereby not
visible from outside. The triggering of the device occurs by means of sensor
technology 10,
which is adapted to the front of the rail vehicle which detects the frontal
impact of a person 2 by
means of optical, mechanical or another measurement principle, or anticipates
the impact. As
regards the expansion speed, the mechanism is laid out in such a way that the
final geometry
of the molding body is already reached prior to the occurrence of the danger
of the person
being "drawn in". This is normally within a few milliseconds.
So as to fulfill the requirement for a permanent safe functionality of the
personal protection
components, the structure must feature flexible, intatable, tear-resistant and
contact-resistant
properties.
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So as to achieve a high degree of compliance to bending with a high resistance
to tearing, a
special metallic membrane material should be employed which is primarily made
up of a fine
metallic mesh. The mesh structure 12 can be laid out as single-layered, or
multi-layered and
can feature internal and/or external protective coatings made of elastic
materials.
The structure can be laminated on the inside with an elastic film 13 for
control of the pressure
profile, which reduces or totally prevents the escape of gas. In the case of
very fine-meshed
reticulation, it is possible to also omit this internal film in accordance
with the required pressure
decrease specifications. So as to further improve the resistance to tearing,
it is also possible to
fully or partially apply additional protective film 14 on the outer skin. The
Figures 5a through 5c
schematically depict the construction of the inflatable structure 7. In Fig.
5b there is a
one-layer network-structure construction 12¨ gas barrier film 13 and in Fig.
5c a multi-layer
construction with an additional optional tear-away protection layer 14 is
represented, which
can also only be partially affixed.
The following wire mesh will in particular find application in structure 7
according to the
invention:
Stainless steel wire mesh: High strength, stainless materials (materials
1.4306, 1.4301 or
similar, HSS and UHSS)
Mesh gauge: The structure of the wire mesh (mesh gauge, wire
circumference, pattern of the weave) is to be selected on the
basis of specific requirements. For single layer structures, it is,
for example, possible to employ weaved mesh with a gauge of
approximately 45x46 mesh per square inch and a wire
circumference of approximately 200 pm. The use of both even
finer structures (meshes of up to 5 pm, for example, as an
additional gas barrier film (second layer)) as well as coarser
structures for the load-bearing layer with meshes of up to 5 mm
is to be determined on a specific application basis.
Structure of the network: One can use both plane weaves as well as meshes
with other
weave patterns. These are to be selected according to the
in-plane rigidity that is required (directionally-dependent
performance to traction and thrust).
The meshes can also be annealed after weaving to achieve a high degree of
ductility. For the
manufacture of the structure, it is possible to
- lay plane wire meshes on top of one another and join them to seal (Fig.
6a),
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- join toric wire meshes on both ends (Fig. 6b)
- or cushion-like structures that are woven directly (Fig. 6c).
The rail vehicle 1 according to the invention comprises a device (obstacle
deflector), which is
arranged in front of the bump abatement system of the vehicle and which does
not respond
without triggering by an activation device. The same should ensure full
functionality of the
there-above-located bump abatement system in crashes without any danger of
running over a
person.
The triggering of the obstacle deflector occurs either through the operator by
means of the
activation of a device on the operator's console or by means of the automatic
detection
technology (not included in this invention) of the detector device that is
integrated into the
apron of the rail vehicle. In any event the obstacle deflector is triggered by
the first response of
one of these devices. A gas generator thereby inflates the closed metal
structure that is folded
in the initial position. During the unfolding and inflation in the direction
of the roadway, an
additional deflection movement is carried out in accordance with the geometry
of the metal
structure that is fitted, that as it were deflects the person(s) being run
over from going under the
vehicle. This does naturally take for granted a coordination of the geometry
of the closed metal
structure to the relationship between the frontal cladding and the roadway.
The closed, folded metal structure that is fitted can also be constructed in
multiple elements so
as to compensate for particular bends of the bumper bar.
A particular feature of the activated (= inflated) closed metal structure and
thus a clear
improvement on the known airbag technologies, is that after the inflation
stage, it maintains its
shape both in position and location. This means that following the
pressurization (= inflation
stage), there is per se no need for (constant) pressure in the structure to
maintain the same in
an inflated state. However, the closed metal structure can in fact adapt to
varying vertical
spatial conditions such as, for example, a reduction of the nominal ground
clearance between
the bumper bar and the roadway: it simply gets compressed through the inherent
weight of the
vehicle. Following this reduction of the height of the closed metal structure,
the same remains
in this state of reduced height.
The total process of the recognition of the obstacle, as well as triggering
and inflation of the
closed metal structure should thereby occur in real time. In any event, as
regards being run
over, the action for the protection of persons that takes place in parallel to
the timely stopping
of the rail vehicle will be complemented by this invention, before a person
can be drawn in or
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run over by the vehicle.
