[0001] The present invention relates to an energy absorbing end terminal system for a crash
barrier. In particular, the invention relates to an energy absorbing end terminal
system comprising a rail and an impact device.
[0002] Crash barriers are provided along the centre or side of vehicle carriageways for
restraining impacting vehicles along their length, by absorbing energy from the collision.
There remains the problem of designing barriers with end-on or obliquely/end-on collisions
in mind. When a barrier terminates (into a ground anchorage or otherwise), the end
of the crash barrier may itself present a danger to an oncoming vehicle in the event
of an end-on collision. For example, if a vehicle impacts the end of a W-section crash
barrier end-on, there is a risk that the end or edge of the barrier could penetrate
the vehicle without providing an effective decelerating force on the vehicle itself.
[0003] US2006/054876A1 discloses a vehicle crash cushion for decelerating a vehicle includes front and rear
anchors spaced along a longitudinal direction and at least one deformable attenuator
member extending in the longitudinal direction and having a first end coupled to the
front anchor and a second end coupled to the rear anchor.
[0004] EP2441889A2 discloses a method and apparatus to continuously secure a displacement while dynamic
kinetic energy of a vehicle is absorbed by a kinetic frictional force and rolling
force produced by dragging a surface of a soft rolled tube, and to let an evaluation
index of PHD belong to a passenger safety index by slowly maintaining the maximum
deceleration applied to the vehicle and passenger, thereby preventing a human in safe
against fatal impact.
[0005] EP2314772A2 discloses a mechanism for the absorption of the kinetic energy of a vehicle frontally
impacting against a containment system, such as an impact attenuator or barrier terminal,
by means of the longitudinal propagation of the plastic deformation of one or more
longitudinal deformable metallic profiles produced by means of a rigid ram which is
displaced along the deformable profile, intercepting part of its cross-section, joined
to a structural element of the system which receives and transmits the impact of the
vehicle being displaced along the containment system, the deformable profile being
directly or indirectly fixed to the ground and therefore remaining static during the
impact.
[0006] There is therefore a need to provide a means for decelerating an impacting vehicle
in the event of end-on barrier collisions. The present invention has been devised
with the foregoing in mind.
[0007] The present invention relates to an energy absorbing end terminal system according
to claim 1.
[0008] In some examples, the rail comprises at least one cut out. In some examples, in an
initial pre-impact position the at least one shearing element projects into the at
least one first cut-out in the rail. In some examples, the shearing element is arranged
to shear the rail on movement of the impact device relative to the rail, for example
during an impact of a vehicle into the impact device.
[0009] Upon an end-on collision of a vehicle into the impact post, load is transferred from
the impact post to the shearing element(s), causing the shearing element(s) to shear
through the rail in the longitudinal direction as the impact device travels along
the rail. The impact device thus provides a shearing effect, which may be continuous,
on the material of the rail which brings the vehicle to stop within the length of
the rail. Thus, the rail itself provides a control mechanism for slowing an impacting
vehicle. The invention provides an arrangement which is simple to manufacture and
assemble, thus reducing costs.
[0010] According to a second aspect of the present disclosure, there is provided a barrier
system comprising a crash barrier and an energy absorbing end terminal system in accordance
with the first aspect of the invention. The rail may be connected to the crash barrier
by a connection piece. The rail may be supported along its length by one or more support
posts.
[0011] In accordance with a third aspect of the present disclosure, there is provided an
impact device for an energy absorbing end terminal system, the impact device comprising:
a base member for slidably mounting on a rail;
an impact post extending generally upwardly from the base member; and
at least one shearing element extending from the base member.
[0012] The shearing device may extend from an opposing side of the base member to the impact
post.
[0013] The following statements may be applicable to the first, second, third and/or fourth
aspects of the invention, as appropriate.
[0014] The rail may be of any size and shape which is suitable for forming the end terminal
of a crash barrier. In use, the rail may be inclined relative to the horizontal, extending
from an end of a crash barrier to the ground. The "terminus" of the rail, as used
herein, refers to the free end of the rail (i.e. the end not corrected to the crash
barrier).
[0015] In some examples, the rail is rectangular in cross section. Alternatively, the rail
may be square, circular or I-shaped in cross section, or any other convenient shape.
[0016] The rail may be solid, or it may be hollow, i.e. in the form of a tube. A hollow/tubular
rail makes it easier for the shearing element(s) to shear the material of the rail.
Bv controlling the thickness of the material forming the rail, the resistance of the
rail to shearing, and thus the rate at which a colliding vehicle is slowed, can be
controlled. In some examples, the rail is in the form of a tube. The tube may be formed
from a material such as metal (e.g. steel). The material forming the tube may have
a thickness of from 2 mm to 8 mm, or from 3 mm to 6 mm (e.g. 4 or 5 mm).
[0017] The first cut-out in the rail allows the shearing element to project into the rail
in the pre-impact position, such that the shearing element cuts through the rail upon
collision of a vehicle with the impact device. In some examples wherein the rail is
in the form of a tube, the first cut-out is a hole or slot in a wall of the rail.
In further examples, a portion of one or more side walls of the rail may cut-away
at a terminus of the rail. For example, the rail may be in the form of a tube of rectangular
cross-section wherein a top wall of the rail is cut away at the terminus of the rail,
thereby creating an open channel. In some examples (for example wherein the rail is
solid), the cut-out is a groove or notch in a surface of the rail. It will be appreciated
that the first cut-out is be sized and shaped so as to receive the shearing element
therein in the pre-impact position.
[0018] In some examples, the first cut-out is formed in an (in-use) upper surface or top
wall, or in a lower surface or bottom wall, of the rail. In some examples, the first
cut-out is formed in one or both side walls of the rail. In further examples, first
cut-outs are formed in the upper surface/top wall, the lower surface/bottom wall and/or
in one or both sides of the rail. For example, the first cut-out may extend completely
through the rail from the upper surface or top wall to the lower surface or bottom
wall, or from one side of the rail to the other.
[0019] In some examples the first cut-out is a slot for receiving a shearing element, such
as a blade, therethrough. The slot may be sized and shaped to receive the shearing
element with a snug fit. In some examples the slot extends in a direction parallel
to the longitudinal axis of the rail. Alternatively, the slot may be angled relative
to the longitudinal axis of the rail. This provides greater frictional resistance
to shearing.
[0020] In some examples, the or each first cut-out in the rail is positioned such that,
when the impact device is mounted on the rail (prior to vehicle impact), the or each
first-cut out is aligned with a corresponding second cut-out in the base member, so
that or each shearing element(s) can pass through the cut-outs in both the base member
and the rail. This arrangement facilitates
in situ assembly of the system. For example, where the first cut-out is a notch, and the
end of the rail is open at its in-use upper side, the impact device may be slid onto
the rail, thus facilitating easy assembly.
[0021] The base member is configured to secure the impact device on the rail while being
moveable relative thereto. A vehicle colliding end-on with the impact post thus causes
the impact device to slide along the rail in the direction of impact. The base member
may extend entirely around the rail or only partially around the rail. The base member
may have a cross section having a shape which substantially matches the cross section
of the rail. In examples, the base member may have a C shaped cross-section, which
is open at the lower edge of the rail, and wraps only partially around the lower edge
to hold itself onto the rail, while otherwise generally confirming to the outer cross-sectional
contour of the rail. This allows the impact device to pass over a support post holding
the rail in position on above the ground its incline. The support post assists in
keeping the rail straight and avoiding buckling during impact as the base member of
the impact device moves along the rail.
[0022] In some examples, the base member is a sleeve which is configured to receive the
rail therethough. In such examples it will be appreciated that the area of the cross
section of the base member will be greater than that of the rail so as to allow the
base member to slide along the rail. Alternatively, the base member may be C-shaped
or U-shaped, or any other suitable shape in cross-section.
[0023] In some examples, the base member is elongate, having a first end and a second end.
When the base member is mounted on the rail, the first end is proximal to the terminus
of the rail and a second end is distal to the terminus of the rail.
[0024] In some examples the base member comprises one or more second cut-outs for receiving
a shearing element therethrough. The second cut-out may be formed in an (in-use) upper
surface of the base member, and/or in one or both sides of the base member. The second
cut-outs may be sized and shaped to receive the shearing elements with a snug fit.
The second cut-out may be a hole or a slot. The shearing elements may be held in the
second cut-outs by any suitable means, for example bolts, screws or welding.
[0025] In an initial pre-impact position the first and second cut-outs of the rail and base
member may be aligned and the shearing element is positioned in said first and second
cut-outs so as to prevent relative movement of the rail and the impact device in the
absence of an impact force.
[0026] In some examples, the second cut-out is a slot. The slot may extend in a direction
corresponding to the longitudinal axis of the base member and the rail. Alternatively,
the slot may be angled relative to the longitudinal axis of the base member and the
rail. Angled slots provide greater frictional resistance to the shearing effect.
[0027] The impact post extends generally upwardly from the base member. In some examples,
the angle (θ) measured along the longitudinal axis between the impact post and the
base member is 90°. In other examples the angle may be more or less, for example from
45° to 120°, from 50° to 110°, from 60° to 100° or from 70° to 80°. The common plane
in which the impact post and the longitudinal axis of the rail lie may be vertical
or inclined to the vertical.
[0028] In some examples, the impact post extends from or adjacent a first end of the base
member.
[0029] The post and the base member may be integrally formed. Alternatively, the impact
post and the base member may be separate components welded, screwed, bolted or otherwise
secured to each other. The post may be of any suitable size and shape. In some examples,
the post is substantially rectangular in cross section. Alternatively, the post may
be square or circular, or any other suitable shape, in cross section.
[0030] The post may be solid, or it may be hollow, i.e. in the form of a tube. Hollow components
are advantageous in that they are lighter, facilitating transport and assembly, as
well as more cost-effective.
[0031] In some examples, the impact device comprises a single shearing element. In some
examples, the impact device comprises two, three, four or more shearing elements.
[0032] The shearing element may be any element which is capable of shearing or cutting through
the rail material due to the force applied by a colliding vehicle on the impact device.
For example, the shearing element may be a blade or a bolt. In some examples, the
shearing element is a blade. The blade may have a cutting edge which faces generally
away from the impact post and which, when the impact device is mounted on the rail,
is aligned with the longitudinal axis of the rail. In other words, the blade faces
the direction of travel of an impacting vehicle such that upon impact, the blade(s)
shears the rail enabling the impact device to travel along the rail. In some examples
in which the slot is angled relative to the longitudinal axis of the base member and/or
the rail, the blade is also angled by the same degree.
[0033] The cutting edge of the blade can be shaped as required so as to control the shearing
effect of the blade. As viewed from above, the cutting edge of the blade may be shaped
to have a flat or square edge, a sharp or flat point, a rounded tip, or be provided
with one or more teeth. In some examples, the cutting edge is asymmetrical. Asymmetrical
blades may conveniently help to direct the sheared material more controllably.
[0034] It will be appreciated that the thickness of the blade will be selected according
to the thickness of the rail material to be sheared. Generally, the thicker the rail
material, the thicker the blade must be, although it will also be understood that
the thickness of the blade will also depend on the materials of both the rail and
the blade. In some examples, the blade is from 5 mm to 30 mm thick, or from 10 mm
to 20 mm thick, e.g. about 15 mm thick.
[0035] The shearing element is secured to the base element of the impact device. In some
examples, the shearing element is attached to an inner or rail-facing surface of the
base member. In these examples, second cut-outs in the base member for receiving the
shearing elements are not required. Alternatively, the shearing element is secured
in a second cut-out in the base member. The shearing element may be attached to the
base element by any suitable means, for example by screw, bolts or by welding.
[0036] In some examples, the impact post extends from a first face of and generally away
from the base member, while the or each shearing element extends from an opposite
face and generally away from the base member. In other words, the impact post and
the or each shearing element extend away from the base member in opposite directions.
[0037] The shearing element is formed from a material which is capable of shearing the rail.
The hardness of the shearing element, relative to that of the rail, determines the
level of resistance of the rail to shearing by the shearing elements and the energy
required for the shearing element to cut through the rail and, in turn, the rate at
which an impacting vehicle is slowed and eventually brought to a stop. Thus, the material
of the shearing element and the rail, the relative thicknesses of the shearing element
and the rail, and the number of shearing elements, can all be selected according to
the desired rate of deceleration of the impacting vehicle. The invention thus enables
greater control over the arresting of an impacting vehicle.
[0038] In some examples, the shearing element is formed from a hardened material (e.g. hardened
steel). It will be appreciated by those skilled in the art that hardened materials
are those which have undergone e.g. a heat-treatment process that increases their
hardness as compared to the untreated material. In some examples wherein the impact
device comprises two or more shearing elements, the shearing elements may all be formed
from the same material, or they may be formed from different materials. In some examples,
one or more of the shearing elements are formed from a hardened material while the
other shearing element(s) are formed from a non-hardened material. Altematively, all
of the shearing elements may be formed from a hardened or a non-hardened material.
[0039] In some examples, the energy absorbing end terminal system for a crash barrier comprises
a rail having at least one first slot, which may be elongated in the direction of
the longitudinal axis of the rail, and an impact device, the impact device comprising:
a base member slidably disposed on the rail, said base member being provided with
at least one second elongate slot;
an impact post extending generally upwardly from the base member; and
at least one blade extending from the base member,
wherein in an initial pre-impact position the first and second elongate slots are
aligned and the blade is secured in said first and second elongate slots so as to
prevent relative movement of the rail and the impact device in the absence of an impact
force.
[0040] In some examples the impact device further comprises a bracing strut. The bracing
strut may be arranged so as to provide additional support to the post and prevent
the post from bending upon vehicle impact.
[0041] In some examples, the bracing strut extends at an angle between the impact post and
a second end, or adjacent the second end, of the base member. It will be appreciated
that the angle of the bracing strut will be selected in accordance with the height
of the impact post and the length of the base member.
[0042] In some examples the impact post and/or the strut is selected or modified so as to
absorb some of the energy on initial contact of a colliding vehicle with the impact
post. For example, the stiffness of the post and/or strut may be selected to allow
the post and/or strut to deform in a controlled manner during impact. Alternatively,
the post and/or strut may have holes therein to enable localized collapse during impact.
[0043] In some examples wherein the base member comprises one or more second cut-outs for
receiving one or more shearing elements, an end of the bracing strut may attach to
the base member at a position which is adjacent to, or overlapping with, the second
cut-outs. This arrangement helps to stiffen the impact device at the point where the
shearing elements are positioned, which in turn helps to prevent unwanted movement
of the shearing element(s) in the cut-out(s). In some examples, the shearing element(s)
is (are) positioned in the region of the strut, and may be connected to the strut
to provide a stronger connection between the shearing element and the base member.
In this way, by having the force required to shear the base member, or move the shearing
element relative to the base member, significantly higher than the force required
to shear the rail, the shearing member can be maintained on the base member when shearing
of the rail occurs. In some examples, the shearing element is placed below or in the
region of the post, rather than below or in the region of the strut. In this way,
the base element is guided by the rail, and the shearing element trails a large part
of the base member, and is thus more stable. If desired, the shearing element can
be placed under the strut, which may encourage some rotation of the shearling element
relative to the rail, thus increasing the energy absorbed. If more than one shearing
element is provided, they may be arrange in any combination under or in the region
of the strut and/or post, or elsewhere in relation to the base member. The shearing
member may be arranged to trail the base member partially or entirely, or to lead
it partially or entirely, in a direction away from the terminus of the rail.
[0044] In some examples the energy absorbing end terminal system further comprises a base
plate for fixing the terminus of the rail to the ground. In some examples the base
plate is substantially rectangular, although other suitable shapes may be used. The
base plate may be bent to provide a ground portion which can be fixed flat against
the ground, and an angled portion for connecting to the rail and which enables the
rail to extend upwardly from the ground. The rail may be attached to the base plate
by any suitable means, for example by welding. The base plate may be fixed to the
ground by any suitable ground restraint means. For example, the base plate may comprise
one or more holes for receiving bolts by which the plate can be secured to the ground.
[0045] In some examples, the rail comprises one or more discontinuities in the material,
i.e. points or regions where the force required to shear the plate is reduced relative
to the rest of the rail. For example the discontinuities may be holes or cuts in the
material of the rail, or may be portions where the thickness of the rail is reduced.
These discontinuities may be placed in the (in-use) upper surface of the rail. In
examples, they can be modified and configured on manufacture of the rail to control
and adapt the force required to shear the rail along the length of the rail. Providing
more or larger discontinuities in the rail reduces the force required to shear the
rail, and increases the length of travel of the impact device along the rail for a
given impact energy. The positioning of the discontinuities can be tailored to modulate
the shear force at different parts of the rail. For example, the initial shearing
force required as the impact device begins to shear the rail may be relatively low,
by providing a relatively high number of and/or size of discontinuity. In this way
small vehicles are not halted too abruptly. Further along the rail away from the pre-impact
position of the impact device, the number and/or size of the discontinuities can be
decreased. If an impact causes the impact device to travel so far along the rail,
then the vehicle or at least the total energy contained in the impacting vehicle is
larger. Then greater shearing force is required in this further region to halt the
vehicle, without requiring a higher length of rail.
[0046] In some examples, one or more elongate plates may be provided underneath the upper
surface of the rail, which may be inside the rail where it is of tubular construction.
The plate(s) may be bolted to the inside of the upper (in-use) side of the rail. The
length of the bolts may be chosen so that the end of the bolt distal its head. The
thickness and/or hardness of the plate may be different from that of the rail. It
may also vary along the length of the rail, for example, by placing different plates
in different positions along the rail. The plate(s) may also include discontinuities
(egg holes) along its (their) length. This (these) may also be varied along the length
of the plate for similar reasons as discussed above in relation to discontinuities
placed in the rail. The discontinuities may be placed only in part of the plate.
[0047] In addition to, or instead of the discontinuities, rods or bolts or short horizontal
plates across the inside of the rail which are sheared by the shearing element in
addition to the rail, and plate, if provided, and thus contribute to the energy absorption
and allow for greater absorption per unit of length along the rail. In these ways,
the absorption can be configured easily as required.
[0048] Preferred example is square lead on blade - gives double shear, as each corner is
separate shear into rail, rather than a point which only provides a single shear point.
[0049] The base can be raised (egg by around 120mm or another amount), using a packer, between
the base plate and the base member. This allows for redirection of a vehicle during
initial impact, and avoids a wheel of the vehicle riding up onto the rail.
[0050] In some examples, the rail comprises one or more energy-absorbing elements along
its length. Two or more energy-absorbing elements may be spaced along the length of
the rail. The energy-absorbing elements are positioned such that, upon vehicle impact,
the shearing element(s) shears through one or more of the energy absorbing elements
in addition to the rail. The energy-absorbing elements may be in the form of a pin,
bolt, plate or any other suitable structure which increases the thickness of the material
through which the shearing element passes or provides additional resistance. The energy-absorbing
elements may include a sleeve or collar of similar construction to the base member
and at least one further shearing element. It may include one or more pins, bolts,
blades, plates or other shearing structure. The energy-absorbing element(s) may comprise
one or more blades, arranged in a similar manner to the arrangement of the base member,
and/or in any of the configurations discussed above. Such an arrangement allows multiple
stage impact energy absorption. Small vehicles involved in an impact may not require
such additional absorption, and having too much absorption initially may cause severe
deceleration of an impacting vehicle, which may not be desirable. However, when a
larger vehicle impacts the terminal, then additional energy absorption is required
and the further energy-absorbing element provides the additional energy absorption
if required. In this way, impacts from different sizes and masses of vehicle can be
accommodated.
[0051] The components of the energy absorbing end terminal system can be formed of any suitable
material, such as metal (e.g. steel). The base member, the post, the bracing strut,
the shearing element and/or the rail may be formed of the same material, or different
materials. In some examples, all components of the system are formed from a metal,
such as steel. In addition, the strut may be partially or fully covered by a cowling
extending at least partially, and in examples fully between the strut, post and base
member. The cowling may be partially or fully structural, holding and retaining the
post relative to the base member. The cowling may cover the hole between the post
and strut, avoiding the potential for objects to be caught in the gap between post
and strut. In a reverse collision, extending the end of the cowling distal from the
post generally upwards and/or away from the post, may reduce tendency for vehicles
impacting from the cowling side of the impact device to rise up over the impact device,
which could cause the vehicle to be deflected excessively upwardly, which is undesirable.
[0052] The base member, the post, the bracing strut and/or the shearing element(s), which
together form the impact device, may be connected together by any suitable means,
for example by bolts, screws or welding. In some examples, one or more parts of the
impact device are integrally formed.
[0053] In some examples, the impact device, or even the energy absorbing end terminal system,
can be assembled prior to installation, enabling quick installation on site. Alternatively,
the system may be assembled
in situ. According to the invention, the impact device itself (or parts thereof) is assembled
on the rail. For example, in examples wherein the shearing element is received in
respective first and second cut-outs in the rail and base member in the pre-impact
position, it may be necessary to position the base member on the rail, and align the
first and second cut-outs, before inserting the shearing element into the cutouts
and securing the shearing element to the base member.
[0054] According to a fourth aspect of the disclosure, there is provided a kit of parts
for an impact device, the kit comprising:
at least one shearing element for shearing a rail;
a base member for slidably mounting on the rail; and
an impact post for mounting on the base member.
[0055] The kit for an impact device may further comprise a bracing strut.
[0056] According to a fifth aspect of the disclosure, there is provided a kit of parts for
an energy absorbing end terminal system, the kit comprising:
a rail;
at least one shearing element for shearing a rail;
a base member for slidably mounting on the rail; and
an impact post for mounting on the base member.
[0057] The kit for an energy absorbing end terminal system may further comprise one or more
of the following components: a bracing strut, a base plate, a connection piece for
connecting the rail to a crash barrier, one or more support posts and one or more
energy-absorbing elements.
[0058] In addition to the post, additional impact members in the form of absorption and/or
guiding means may be provided mounted on the post extending in a direction away from
the rail and safety barrier. These may be any convenient shape, for example hollow
with a round cross-section, which may vary or may be the same over the height of the
absorption means. The hollow cross section allows deformation and thus energy absorption.
These may be mounted to each other and/or the post so that, during an off centre impact,
as well as or instead of collapsing and absorbing energy, they pivot about each other
and/or the post as desired to guide the , vehicle during a collision. The impact members
may be one or more hollow 'cans', mounted directly to one another, and to the post
by any suitable fixing, for example bolting.
[0059] Examples of the disclosure will now be described with reference to the accompanying
figures in which:
Figure 1 shows a crash barrier connected to an energy absorbing end terminal system
in accordance with an embodiment of the present invention;
Figure 2a is a perspective view of an energy absorbing end terminal system in accordance
with an embodiment of the present invention;
Figure 2b is an elevation view of the energy absorbing end terminal system of Figure
2a;
Figure 2c is a plan view of the energy absorbing end terminal system of Figures 2a
and 2b;
Figure 3 is a perspective view of a sleeve for an energy absorbing end terminal system
in accordance with an embodiment of the present invention;
Figure 4 is a perspective view of a section of a rail for an energy absorbing end
terminal system in accordance with an embodiment of the present invention;
Figure 5 is a perspective view of an energy absorbing end terminal system in accordance
with an alternative embodiment of the present invention;
Figure 6 shows plan views of different embodiments of a blade for an energy absorbing
end terminal system in accordance with an embodiment of the present invention;
Figure 7 shows a perspective view of an energy absorbing end terminal system in accordance
with an embodiment of the present invention;
Figure 8 shows a perspective view of an energy absorbing end terminal system in accordance
with an embodiment of the present invention;
Figure 9 shows a plate for use with an energy absorbing end terminal system in accordance
with an embodiment of the present invention;
Figure 10a shows an end portion of a rail for use with an energy absorbing end terminal
system in accordance with an embodiment of the present invention;
Figure 10b shows an energy-absorbing element for use with an energy absorbing end
terminal system in accordance with an embodiment of the present invention;
Figure 11 shows a spacer element for use with an energy absorbing end terminal system
in accordance with an embodiment of the present invention; and
Figure 12 shows a crash barrier connected to an energy absorbing end terminal system
in accordance with an embodiment of the present invention.
[0060] With reference to Figure 1, an energy absorbing end terminal system 10 is connected
to a crash barrier 12 by a connection piece 14. The energy absorbing end terminal
system 10 has a length L indicated by an arrow. The system 10 comprises a rail 16,
which is inclined such that it extends from the height of the crash barrier 12 down
to the ground where it terminates at an end 18. The rail 16 is supported between the
crash barrier 12 and its end 18 by a support post 19. The end 18 of the rail 16 is
mounted on a base plate 20, which is anchored to the ground. An impact device 22 is
mounted on the rail 16, close to the end 18 of the rail 16.
[0061] As shown in more detail in Figures 2a-2c, the impact device 22 comprises a base member
in the form of an elongate sleeve 24 of substantially rectangular cross section which
receives the rail 16 therethrough. The sleeve 24 has a first end 26, which is proximal
to the end 18 of the rail, and a second end 28. The sleeve 24 has a lower, ground-facing
surface 30 and an opposite upper surface 32. An impact post 34 is mounted on the upper
surface 32 of the sleeve 24, towards the first end 26 thereof, and extends upwardly
from the sleeve 24 at a substantially perpendicular angle (θ) thereto. The impact
post 34 is constituted by a hollow tube of substantially rectangular cross section,
the long sides of the rectangle being parallel with the length of the sleeve 24. In
the arrangement shown the post is inclined to the vertical as measured along the longitudinal
axis of the rail. In other embodiments the post may be vertical (θ<90°) or inclined
at a different angle. The post may be configured to both transfer load to the base
member and absorb energy by buckling, for example.
[0062] The impact post 34 is supported on the sleeve by a strut 36. A first end 38 of the
strut 36 is connected to the post 34, close to its top end 42. A second end 44 of
the strut 36 abuts the upper surface 32 of the sleeve 24 towards the second end 28
of the sleeve 24, and angle (α) being subtended of about 45°.
[0063] The base plate 20 has three holes 21 therein, arranged in a triangular pattern, for
receiving bolts (not shown) for attaching the base plate 20 to the ground. As shown
in Figure 2b, the base plate 20 has a slight bend in the middle, thus allowing the
rail 16 to extend upwardly from the ground.
[0064] The impact device 22 further comprises a shearing element in the form of a blade
46, which extends through the upper surface 32 of the sleeve 24. The blade 46 protrudes
above the upper surface 32 of the sleeve 24 and projects into the rail 16. As shown
in Figure 2b, a portion of the blade 46 which shears through the rail passes underneath
the strut 36.
[0065] As can be seen more clearly in Figure 3, the upper surface 32 of the sleeve 24 has
an elongate first slot 48 therein. The slot 48 extends in the direction of the longitudinal
axis of the sleeve 24, towards the second end 28 of the sleeve, and is positioned
centrally.
[0066] As shown in Figure 4, the rail 16 has a corresponding second elongate slot 50 in
an in-use upper surface 52. The second slot 50 in the rail 16 is the same size and
shape as the first slot 48 in the sleeve 24, both slots 48, 50 being sized and shaped
so as to have a snug fit with the blade 46. The second slot 50 is positioned a short
distance from the end 18 of the rail 16, such that when the impact device 22 is mounted
on the rail 16, the first slot 48 of the sleeve 24 is precisely aligned with the second
slot 50 of the rail 16 so that the blade 46 passes through both slots 48, 50.
[0067] Figure 5 shows an alternative embodiment of an energy absorbing end terminal system
100 in accordance with the present invention. The system is substantially the same
as that shown in Figure 3, having an impact device 122 comprising an elongate sleeve
124 having a first end 126 and a second end 128, the sleeve 124 being slidably mounted
on a rail 116. The impact device 122 further comprises an impact post 134 and a supporting
strut 136, having substantially the same arrangement as the embodiment shown in Figure
2a. In this case, however, three blades 146 are provided, the blades 146 passing through
respective slots in an upper surface 132 of the sleeve 124 and the rail 116. The blades
146 are arranged in a parallel fashion, aligned with the longitudinal axis of the
rail 116 and sleeve 124. A middle one of the blades 146 is positioned slightly closer
to the second end 128 of the sleeve 124 than the outer blades. The middle blade passes
beneath the strut 136, while the two outer blades are flush with side faces 160 of
the strut 136. The outer blades may be supported during shearing by welding them to
the side faces 160 of the strut 136. The three-blade arrangement shown in Figure 5
will shear through the rail material at three points, thereby increase the resistance.
[0068] Figure 6 shows various embodiments of blades for use in the present invention, each
embodiment differing in the shape of the leading or cutting edge. The blade may have
a cutting edge which, as viewed from above, is square (Figure 6a), pointed (Figure
6b), rounded (figure 6c), has a flattened point (Figure 6d), is asymmetrical (Figures
6e-6g) or has a number of teeth (Figure 6h).
[0069] Figure 7 shows an alternative embodiment of an energy absorbing end terminal system
in accordance with the present invention. The system is substantially the same as
that shown in Figures 2a-2c and 3 having an impact device 222 comprising an elongate
sleeve 224 having a first end 126 and a second end 128, the sleeve being slidably
mounted on a rail (not shown). Elements not described are the same as described above.
A post 234 is provided extending away from the sleeve 224 in the region of a first
end 226 of the sleeve 224, proximal to the end of the rail, and a strut 236 extends
from a region of a top end 242 of the post 234 at a first end of the strut 238 to
a region of a second end 226 of the sleeve 224, distal to the end of the rail at the
second end of the strut 244. In this embodiment, the shearing element, which again
is in the form of a blade 246, is positioned beneath the post 234, rather than below
the strut 236. As in the embodiment of Figure 5, multiple blades may alternatively
be provided.
[0070] An additional difference between this embodiment and that shown in Figures 2a-2c
is that the sleeve 224 is not closed in cross section, but rather has a generally
'C' shaped cross section, with the opening 250 in the lower ground facing surface
of the sleeve 224. The sleeve 224 extends around the rail (not shown) at two in-turns
255, which engage with the lower surface of the rail and ensure that the sleeve 224
is retained thereon.
[0071] Figure 8 shows a further alternative embodiment of an energy absorbing end terminal
system in accordance with the present invention. The system is similar to that described
above with reference to figure 7, although this embodiment could be applied to any
of the embodiments described herein. Therefore, only differences will be described.
In this embodiment a cowling 360 extends over the strut (not shown) from the post
334 to the sleeve 324, so enclosing the space between the strut, post 334 and sleeve
324. This prevents objects from being caught in the generally triangular hole between
the post 334, strut and sleeve 324 during an impact. In this embodiment, the in-turns
265 are formed by welding separate flanges to the open ends of a 'U' shaped sleeve
324. Therefore, while the sleeve 324 does not engage itself directly with the rail,
the flanges engage with the lower surface of the rail and hold the sleeve 324 onto
the rail. Alternatively, the flanges may be omitted, and the sleeve may be 'C' shaped
in cross-section as shown in Figure 7, while still including the cowl.
[0072] Figure 9 shows an elongate metal plate 400 which can be placed into the rail (not
shown) in the other embodiments described herein. The plate is mounted to the rail
with bolts (not shown) through bolt holes in the rail and bolt holes 410 in the plate
400. The plate 400 includes discontinuities in the form of holes 420. The holes 4210
lie on the path of the blade of the impact device (not shown). The plate increases
the energy required to shear the rail/plate assembly, compared to the rail alone.
The holes 420 reduce the energy required to shear the plate 400, compared with if
it was solid and the holes 420 were not provided. In this way, the energy absorption
of the system by unit length can be modified and configured easily by altering the
gauge of the metal of the plate and/or by changing the size and/or number off holes
420 per unit length.
[0073] Figure 10a shows an alternate end portion 520 of a rail 516 according to an embodiment
of the invention. In this embodiment, the rail 516 has an open in-use upper side 525
in the end portion 520, forming a cut-out in the form of a hole therein. Elements
not described are the same as described above. Where the rail 516 transitions to a
closed cross-section, another cut-out, in the form of a notch 530, is formed. The
notch 530 is substantially 'v' shaped, with the apex pointing away from the end portion
along the elongate length of the rail 516. During assembly of the system, an impact
device (not shown), as described above, is arranged with the blade positioned in the
open end portion 520 of the rail 516. The blade can be positioned to abut with and
lie partially within the notch 530, or may be positioned within hole formed by the
open upper side of the rail 516 in the end portion. In this way, a fully constructed
impact device can slide onto the rail during assembly of the system.
[0074] Figure 10b shows an energy-absorbing element 550 for use in a system according to
an embodiment of the invention. The energy-absorbing element 550 is mounted on a rail
516 and comprises a sleeve 574, which is closed in cross-section, and which conforms
to the outer shape of the rail 516 so that it can slide along the rail 516 during
an impact. The energy-absorbing element 550 comprises, in the present embodiment,
two shearing elements in the form of blades 546. The blades 546 are welded to the
sleeve 574 and extend through the sleeve 574 and through the rail 516, through slots
(not shown). The slots may each include a notch (not shown) at the leading end, to
aid the blade 546 as it starts to shear the rail 516. The relative strengths of the
sleeve 574 and the rail 516 are chosen so that the blades 546 shear the rail 516 and
do not shear through the sleeve 574 as the sleeve 574 travels along the rail 516 during
impact.
[0075] Figure 11 shows a spacer element 600, which can be positioned between the base plate
20 described specifically in Figure 2a and the impact device according to any of the
embodiments described. The spacer element 600 raises the end portion of the rail,
and the impact device positioned thereon, up from the ground. Raising the impact device
from the ground reduces the possibility that a vehicle will ride up over the impact
element and onto the rail.
[0076] Finally, Figure 12 shows a crash barrier connected to an energy absorbing end terminal
system in accordance with an embodiment of the present invention. Figure 12 incorporates
the energy absorbing end terminal system of Figure 7, the rail 516 of figure 10a,
the energy-absorbing element of Figure 10b and the spacing element 600 of Figure 11.
The barrier could alternatively or additionally incorporate the features of any of
the other embodiments, as appropriate. The barrier also comprises additional impact
members 650. One of the impact members 650 is mounted to the post 234 of the impact
device 222. The next impact member 650 is then mounted to the first impact member
650, a further impact member 650 mounted to that impact member 650, and so on.
[0077] The energy-absorbing element 550 is positioned on the rail 516 at a point partway
along the rail 516 between the impact device 222 and the barrier 12. A support post
19 is mounted below the rail 516 part way along its length to maintain the rail straight
so that the impact device 222 can slide along the rail 516.
[0078] During a vehicle collision from the, as shown, left hand side, a vehicle first impacts
with the impact members 650. These are in the form of hollow cylinders or 'cans' and
deform upon impact so providing initial energy absorption. During a glancing or off
centre collision, the impact members 650 may also act as guides to maintain the vehicle
within the carriageway, rather than the vehicle potentially leaving the carriageway
at the side of which the crash barrier is mounted. The force of the impact is also
transferred through the impact members 650 to the impact device 222. The post 234
receives the force from the collision and may be designed to allow some degree of
buckling. The post is maintained generally in position by the strut 236 mounted between
the top of the post 234 and the sleeve 224 of the impact device. The impact device
222 is then pushed up the rail 516, causing the blade 246 to begin shearing the rail
516 (and the internal plate, if provided). The shearing slows the movement of the
impact device consistently, so that, after the initial impact with the barrier, the
rate of energy absorption flattens out. If the vehicle in the collision is a relatively
light vehicle, then the impact device 222 may come to a stop on the rail 516 before
the impact device 222 reaches the energy-absorbing element 550, having brought the
colliding vehicle to a stop over a length of the rail 516 less than the distance to
the energy-absorbing element. However, if the colliding vehicle is a heavy vehicle,
then the impact may push the impact device 222 along the rail 516 to the energy-absorbing
element 550. When the sleeve 224 of the impact device 222 reaches the energy-absorbing
element 550, it abuts the sleeve 574 thereof and the impact device 222 begins to push
the energy-absorbing element 550 along the rail 516. The blades 546 of the energy-absorbing
element 550 thus also begin to shear the rail 516 as well as the blade 246 of the
impact device 222. As the blades 546 of the energy-absorbing element 550 are off-set
laterally relative to the blade 246 of the impact device 222, all three blades 246,
546 then act to shear the rail 516, and the energy absorption rate is increased. Thus
a heavier vehicle, in which more energy absorption is required during the collision,
can be brought to a stop before reaching the end of the rail 516, while a lighter
vehicle is not brought to a stop too quickly on the initial portion of the rail 516.
If desired, more than one energy-absorbing element 550 can be provided, to provide
stepped rates of energy absorption as a vehicle, and the impact device 222 travel
further along the rail during an impact.
1. An energy absorbing end terminal system (10) for a crash barrier (12), the system
comprising a rail (16) having at least one first cut-out (50) therein, with an impact
device (22) being mounted on said rail (16) by a base member (24) disposed on the
rail (16), close to an end thereof, such that the impact device (22), with said base
member (24) is slidable along the rail (16) in a longitudinal direction;
the impact device further comprising:
an impact post (34) extending generally upwardly from the base member (24); and
at least one shearing element (46) extending from the base member (24), the impact
post (34) adapted to receive a vehicle in the event of an end-on barrier collision,
wherein in an initial pre-impact position the at least one shearing element (46) projects
into the at least one first cut-out (50) in the rail (16).
2. The energy absorbing end terminal system of claim 1, wherein the or each first cut-out
(50) is a hole, a slot, a groove or a notch in a wall or a surface of the rail.
3. The energy absorbing end terminal system of claim 1 or claim 2, wherein the or each
first cut-out (50) is a slot for receiving the shearing element (46) therethrough,
and optionally, wherein the slot extends in a direction parallel to the longitudinal
axis of the rail (16).
4. The energy absorbing end terminal system of any one of claims 1 to 3, wherein the
base member (24) is a sleeve which is configured to receive the rail (16) therethough.
5. The energy absorbing end terminal system of any one of the preceding claims, wherein
the or each shearing element (46) is attached to an inner or rail-facing surface of
the base member (24).
6. The energy absorbing end terminal system of any one of claims 1 to 4, wherein the
base member (24) comprises at least one second cut-out (48), wherein the or each second
cut-out (48) receives a shearing element (46,) therethrough, and wherein in an initial
pre-impact position the first (50) and second (48) cut-outs are aligned and the or
each shearing element (46) is positioned in said first (50) and second (48) cut-outs
so as to prevent relative movement of the rail (16) and the impact device (22) in
the absence of an impact force, and optionally, wherein the or each second cut-out
(48) is an elongate slot which extends in a direction parallel to the longitudinal
axis of the rail (16).
7. The energy absorbing end terminal system of any one of the preceding claims, wherein
the or each shearing element (46) is a blade, and optionally, wherein the blade has
a thickness of from 10 to 20 mm.
8. The energy absorbing end terminal system of any one of the preceding claims, wherein
the shearing element (46) is formed from a hardened material.
9. The energy absorbing end terminal system of any one of the preceding claims, wherein
the impact device (22) further comprises a bracing strut (36) which extends at an
angle between the impact post (34) and the base member (24).
10. The energy absorbing end terminal system of claim 9 when dependent on claim 6, wherein
an end of the bracing strut (36) attaches to the base member (24) at a position which
is adjacent to, or overlapping with, the or each second cut-out (48).
11. The energy absorbing end terminal system of any one of the preceding claims, further
comprising a base plate (20) for fixing a terminus of the rail (16) to the ground.
12. The energy absorbing end terminal system of any one of the preceding claims, wherein
the rail (16) comprises one or more energy-absorbing elements (550) positioned along
its length such that, upon vehicle impact, the or each shearing element (46) shears
through the energy absorbing elements (550) in addition to the rail (16).
13. A barrier system comprising a crash barrier (12) and an energy absorbing end terminal
system (10) in accordance with any one of claims 1 to 12.
1. Energieabsorbierendes Endstücksystem (10) für eine Crashbarriere (12), wobei das System
eine Schiene (16) umfasst, welche mindestens einen ersten Ausschnitt (50) darin aufweist,
mit einer Aufprallvorrichtung (22), welche auf der Schiene (16) durch ein Basiselement
(24) montiert ist, welches auf der Schiene (16) in der Nähe eines Endes derselben
derart angeordnet ist, dass die Aufprallvorrichtung (22) mit dem Basiselement (24)
entlang der Schiene (16) in einer Längsrichtung verschiebbar ist;
wobei die Aufprallvorrichtung ferner umfasst:
einen Aufprallpfosten (34), welcher sich im Wesentlichen nach oben von dem Basiselement
(24) erstreckt; und
mindestens ein Scherelement (46), welches sich von dem Basiselement (24) erstreckt,
wobei der Aufprallposten (34) ausgebildet ist, um ein Fahrzeug im Falle einer frontalen
Kollision mit einer Barriere aufzunehmen, wobei in einer anfänglichen Voraufprallposition
das mindestens eine Scherelement (46) in den mindestens einen ersten Ausschnitt (50)
in der Schiene (16) hineinragt.
2. Energieabsorbierendes Endstücksystem nach Anspruch 1, wobei der oder jeder erste Ausschnitt
(50) ein Loch, eine Nut, eine Rille oder ein Einschnitt in einer Wand oder in einer
Oberfläche der Schiene ist.
3. Energieabsorbierendes Endstücksystem nach Anspruch 1 oder 2, wobei der oder jeder
erste Ausschnitt (50) eine Nut zum Aufnehmen des Scherelements (46) durch denselben
ist, und optional, wobei die Nut sich in einer Richtung erstreckt, welche parallel
zur Längsachse der Schiene (16) läuft.
4. Energieabsorbierendes Endstücksystem nach einem der Ansprüche 1 bis 3, wobei das Basiselement
(24) aus einer Hülse besteht, welche konfiguriert ist, um die Schiene (16) durch dieselbe
aufzunehmen.
5. Energieabsorbierendes Endstücksystem nach einem der vorhergehenden Ansprüche, wobei
das oder jedes Scherelement (46) an einer inneren oder schienenzugewandten Oberfläche
des Basiselements (24) befestigt ist.
6. Energieabsorbierendes Endstücksystem nach einem der Ansprüche 1 bis 4, wobei das Basiselement
(24) mindestens einen zweiten Ausschnitt (48) umfasst, wobei der oder jeder zweite
Ausschnitt (48) ein Scherelement (46) durch denselben aufnimmt, und wobei in einer
anfänglichen Voraufprallposition, die ersten (50) und zweiten (48) Ausschnitte ausgerichtet
sind und das oder jedes Scherelement (46) in den ersten (50) und zweiten (48) Ausschnitten
derart angeordnet ist, dass eine relative Bewegung der Schiene (16) und der Aufprallvorrichtung
(22) bei fehlender Aufprallkraft verhindert wird, und optional wobei der oder jeder
zweite Ausschnitt (48) aus einer länglichen Nut besteht, welche sich in einer Richtung
erstreckt, welche parallel zur Längsachse der Schiene (16) läuft.
7. Energieabsorbierendes Endstücksystem nach einem der vorhergehenden Ansprüche, wobei
das oder jedes Scherelement (46) eine Klinge ist, und optional wobei die Klinge eine
Dicke zwischen 10 und 20 mm aufweist.
8. Energieabsorbierendes Endstücksystem nach einem der vorhergehenden Ansprüche, wobei
das Scherelement (46) aus einem gehärteten Material besteht.
9. Energieabsorbierendes Endstücksystem nach einem der vorhergehenden Ansprüche, wobei
die Aufprallvorrichtung (22) ferner eine Verstrebung (36) umfasst, welche sich in
einem Winkel zwischen dem Aufprallpfosten (34) und dem Basiselement (24) erstreckt.
10. Energieabsorbierendes Endstücksystem nach Anspruch 9, wenn von Anspruch 6 abhängig,
wobei ein Ende der Verstrebung (36) an dem Basiselement (24) an einer Stelle befestigt
ist, welche dem oder jedem zweiten Ausschnitt (48) benachbart ist oder diesen überlappt.
11. Energieabsorbierendes Endstücksystem nach einem der vorhergehenden Ansprüche, ferner
umfassend eine Basisplatte (20) zum Befestigen eines Endpunkts der Schiene (16) an
dem Boden.
12. Energieabsorbierendes Endstücksystem nach einem der vorhergehenden Ansprüche, wobei
die Schiene (16) ein oder mehrere energieabsorbierende Elemente (550) umfasst, welche
entlang ihrer Länge derart angeordnet sind, dass, bei einem Fahrzeugaufprall, das
oder jedes Scherelement (46) durch die energieabsorbierende Elemente (550) zusätzlich
zu der Schiene (16) schneidet.
13. Barriere-System, umfassend eine Crashbarriere (12) und ein energieabsorbierendes Endstücksystem
(10) nach einem der Ansprüche 1 bis 12.
1. Système d'extrémité absorbant l'énergie (10) destiné à une glissière de sécurité (12),
le système comprenant un rail (16) présentant au moins une première découpe (50) pratiquée
dans celui-ci, un dispositif d'impact (22) étant monté sur ledit rail (16) par l'intermédiaire
d'un élément de base (24) disposé sur le rail (16), à proximité d'une extrémité de
celui-ci, de telle façon que le dispositif d'impact (22), avec ledit élément de base
(24), peut coulisser le long du rail (16) dans un sens longitudinal ;
le dispositif d'impact comprenant en outre :
un poteau d'impact (34) s'étendant généralement vers le haut à partir de l'élément
de base (24), et
au moins un élément de cisaillement (46) s'étendant à partir de l'élément de base
(24), le poteau d'impact (34) étant adapté pour recevoir un véhicule dans l'éventualité
d'une collision frontale avec la glissière, ledit au moins un élément de cisaillement
(46) faisant saillie, dans une position de pré-impact initiale, dans l'au moins une
première découpe (50) pratiquée dans le rail (16).
2. Système d'extrémité absorbant l'énergie selon la revendication 1, dans lequel la ou
chaque première découpe (50) consiste en un trou, une fente, une rainure ou une encoche
dans une paroi ou une surface du rail.
3. Système d'extrémité absorbant l'énergie selon la revendication 1 ou la revendication
2, dans lequel la ou chaque première découpe (50) consiste en une fente destinée à
recevoir l'élément de cisaillement (46) à travers celle-ci, et facultativement dans
lequel la fente s'étend dans une direction parallèle à l'axe longitudinal du rail
(16).
4. Système d'extrémité absorbant l'énergie selon l'une quelconque des revendications
1 à 3, dans lequel l'élément de base (24) est un manchon configuré pour recevoir le
rail (16) à travers celui-ci.
5. Système d'extrémité absorbant l'énergie selon l'une quelconque des revendications
précédentes, dans lequel le ou chaque élément de cisaillement (46) est lié à une surface
intérieure, ou tournée vers le rail, de l'élément de base (24).
6. Système d'extrémité absorbant l'énergie selon l'une quelconque des revendications
1 à 4, dans lequel l'élément de base (24) comprend au moins une deuxième découpe (48),
la ou chaque deuxième découpe (48) recevant un élément de cisaillement (46) à travers
celle-ci et dans lequel, dans une position de pré-impact initiale, les première (50)
et deuxième (48) découpes sont alignées et le ou chaque élément de cisaillement (46)
est positionné dans lesdites première (50) et deuxième (48) découpes de façon à empêcher
le mouvement relatif du rail (16) et du dispositif d'impact (22) en l'absence de toute
force d'impact et, facultativement, dans lequel la ou chaque deuxième découpe (48)
consistant en une fente allongée s'étendant dans une direction parallèle à l'axe longitudinal
du rail (16).
7. Système d'extrémité absorbant l'énergie selon l'une quelconque des revendications
précédentes, dans lequel le ou chaque élément de cisaillement (46) est une lame et,
facultativement, dans lequel la lame a une épaisseur allant de 10 à 20 mm.
8. Système d'extrémité absorbant l'énergie selon l'une quelconque des revendications
précédentes, dans lequel l'élément de cisaillement (46) est réalisé dans un matériau
trempé.
9. Système d'extrémité absorbant l'énergie selon l'une quelconque des revendications
précédentes, dans lequel le dispositif d'impact (22) comprend en outre une contrefiche
(36) s'étendant, de manière inclinée, entre le poteau d'impact (34) et l'élément de
base (24).
10. Système d'extrémité absorbant l'énergie selon la revendication 9, lorsqu'elle dépend
de la revendication 6, dans lequel une extrémité de la contrefiche (36) est liée à
l'élément de base (24) en une position adjacente à la ou à chaque deuxième découpe
(48), ou en une position chevauchant celle-ci.
11. Système d'extrémité absorbant l'énergie selon l'une quelconque des revendications
précédentes, comprenant en outre une plaque de base (20) destinée à la fixation d'une
terminaison du rail (16) au sol.
12. Système d'extrémité absorbant l'énergie selon l'une quelconque des revendications
précédentes, dans lequel le rail (16) comprend un ou plusieurs éléments absorbeurs
d'énergie (550) positionnés sur sa longueur de telle manière que, lors d'un impact
par un véhicule, le ou chaque élément de cisaillement (46) effectue un cisaillement
à travers les éléments absorbeurs d'énergie (550) en sus du rail (16).
13. Système de glissière comprenant une glissière de sécurité (12) et un système d'extrémité
absorbant l'énergie (10) selon l'une quelconque des revendications 1 à 12.