[0001] The invention relates to an end terminal for a safety guardrail, said end terminal
comprising an elongated beam which is on opposite ends connected to a ground anchor
and to the safety guardrail, respectively, and further comprising a collision catcher
which is slidably mounted on the beam, wherein the collision catcher connects to a
sliding block with an aperture through which the beam is guided.
[0002] Such an end terminal for a safety guardrail is known from
EP-B-2 646 624. This known end terminal for a safety guardrail comprises an energy absorbing device
and a metallic, elongated draw element, one of which is connected to the collision
catcher, and wherein the impact energy of a collision is absorbed due to a relative
movement of the elongated draw element and the energy absorbing device.
[0003] Any end terminal for a safety guardrail is required to pass a series of ENV1317-4:2002
crash tests. The EN1317 European crash test standard is developed within the framework
of the Construction Products Directive 89/106/EEC and EN1317-5 serves as a basis for
the CE marking of road safety systems such as safety barriers and guardrails, crash
cushions, barrier extremities and transitions. One of these tests is a head on impact
at 110km/h with a 1500kg car to get a classification in the energy absorbing class
of EN1317. In order to achieve this, it is desirable for the vehicle to be decelerated
in a smooth manner.
[0004] The current invention relates to several aspects of such an end terminal for a safety
guardrail that can be applied independently from each other, but also cumulative wherein
in the latter situation the best results may be achieved.
[0005] A first aspect of the invention concerns the feature that inside the aperture the
sliding block is provided with one or more protruding deformation elements that engage
the beam so as to arrange that upon movement of the sliding block towards the safety
guardrail, the deformation elements provide a depressed portion in the beam that extends
towards the safety guardrail. As the sliding block moves along the beam during vehicle
impact, the deformation elements thus deform the beam, which takes energy and slows
the car down.
[0006] For mounting the sliding block on the elongated beam it may be preferable that the
elongated beam has an initial depressed portion in which the one or more protruding
deformation elements protrude.
[0007] To promote the achievements of the invention it is preferred that the elongated beam
has a substantially square or rectangular cross-section, and that at least two deformation
elements are provided within the aperture on the sliding block, and projecting to
opposite sides of the elongated beam reaching through the sliding block. The sliding
block is then mounted in a more or less balanced way on the elongated beam, and the
further depression of the elongated beam during impact can then take place on opposite
sides of the elongated beam so as to secure the maintenance of a stable movement of
the sliding block along the elongated beam during slowing down of the impacting car.
[0008] In a second aspect of the invention, which can be applied independently or in combination
with any of the other features of the invention, it is preferred that the sliding
block is provided with at least one of upper wall portions inside the aperture that
directly engage the elongated beam for support of the sliding block, and that in or
between said at least one of upper and lower wall portions a slit or slits are provided
providing room for passing of bolt heads or other fixtures extending from the elongated
beam. Preferably the sliding block (5) is also provided with at least one of lower
(5") wall portions inside the aperture (6) that directly engage the elongated beam
(2) for support of the sliding block (5), and that in or between said at least one
of lower (5") wall portions a slit (9) or slits are provided providing room for passing
of bolt heads (10) or other fixtures extending from the elongated beam (2).
[0009] In an alternative embodiment regarding this second aspect of the invention, the sidewalls
of the sliding block are provided with indents protruding inwardly into the aperture
through which the elongated beam is guided, wherein said indents directly engage the
elongated beam for support of the sliding block whilst providing room for passing
of bolt heads or other fixtures extending from the elongated beam.
[0010] With respect to the above-mentioned second aspect of the invention it is remarked
that, with current state-of-the-art end terminal designs, if a vehicle heavier or
travelling at a higher speed than the above-mentioned 1500kg car traveling at 110km/h
were to impact the end terminal, once the prescribed energy had been absorbed, the
terminal would cease to function in its desired way and could be dangerous. The just
mentioned two embodiments relating to the second aspect of the invention are embodied
with features which secure that the end terminal will continue to absorb energy beyond
the EN1317 requirement for as long as is needed to bring the vehicle to rest. To achieve
this result it is instrumental that the sliding block will pass over bolted joints
of the elongated beam allowing the end terminal to continue working along its entire
length without getting caught up.
[0011] In still another aspect of the invention, which can be applied independently or in
combination with any of the other features of the invention, it is preferred that
the collision catcher has a hook part, which is preferably upstanding and/or swivable,
for catching behind a bumper of a colliding car. As mentioned above an end terminal
for a safety guardrail is required to pass EN1317 crash tests. One of these tests
in particular causes the car to spin out and away from the end terminal, which can
lead to the vehicle rebounding into other road traffic. The EN1317 standard has criteria
that must be met to gain successful accreditation. The problem is that the nature
of this test is likely to cause the vehicle to spin out beyond limits set in the standard
and therefore fail the test. According to the invention a hooked front end is provided
on the collision catcher which is designed to 'capture' the front bumper of a vehicle
and therefore reduce motion of the vehicle during impact and stay within the limits
prescribed by the test standard EN1317. The hook part can also be embodied with a
locking pin that breaks under impact. The hook part can also be embodied as an active
feature which becomes operational upon impact of a car.
[0012] In still another aspect of the invention, which can be applied independently or in
combination with any of the other features of the invention, it is preferred that
below the elongated beam a stander is provided with a U-shaped receptacle in which
the elongated beam is received. The stander with the U-shaped receptacle only supports
the elongated beam. This has the advantage that the connection between the stander
and the beam is relatively strong in a lateral direction, but relatively weak in a
longitudinal direction.
[0013] Preferably the stander is designed to collapse when the elongated beam is loaded
during the impact of a colliding car.
[0014] In still another aspect of the invention, which can be applied independently or in
combination with any of the other features of the invention, it is preferred that
the elongated beam is provided with at least one insert beam extending over a part
of the length of the elongated beam to provide said elongated beam with portions of
different impact resistance. This differentiates from prior art solutions that are
equipped with a single mechanism for absorbing energy and therefore do not have any
ability to tailor the resistive force level for different vehicle impacts. According
to this particular aspect of the invention the at least one insert beam that extends
over a part of the length of the elongated beam provides it with different levels
of impact resistance, so that one thing and another can be tailored to the required
properties of the end terminal.
[0015] The benefits of applying at least one insert beam in the elongated beam can be further
promoted by arranging that the elongated beam is provided with a plurality of insert
beams, preferably having mutually differing lengths, gauges and/or material properties.
[0016] It is preferable that the at least one insert beam is closer to the safety guardrail
than to the ground anchor in order to provide that upon impact the elongated beam
initially provides a lower impact resistance than at a final stage when the part of
the elongated beam wherein the insert beam is provided becomes operational.
[0017] In still another aspect of the invention, which can be applied independently or in
combination with any of the other features of the invention, it is preferred that
the end terminal is provided with a deflector, wherein the deflector extends below
the elongated beam. This provides a solution for the problem in certain cases of vehicle
impact from an opposite rather than from the regular impact side, that the vehicle
can become wedged between the underside of the elongated beam and the rigid anchor
to the ground. The deflector is arranged to deflect parts of the vehicle (mainly the
wheel) back out away from the anchor to the ground, to prevent such parts from getting
trapped.
[0018] The deflector can either be mounted on the elongated beam or another suitable part
of the end terminal, or to the ground.
[0019] The invention will hereinafter be further elucidated with reference to the drawing
of an exemplary embodiment of an apparatus operating according to a prior art method
and according to the method of the invention that is not limiting as to the appended
claims.
[0020] In the drawing:
- figure 1 shows a detail of an end terminal for a safety guardrail according to the
invention with a view at the sliding block; and
- figure 2A and figure 2B show the sliding block after it has moved over a certain distance
along the elongated beam of the end terminal;
- figures 3A - 3C show the sliding block according to a first embodiment after it has
moved over a certain distance along the elongated beam of the end terminal, also showing
the bolt heads on top of the elongated beam;
- figure 3D shows separately a sliding block according to a second embodiment;
- figure 4A and figure 4B show the end terminal for a safety guardrail, as provided
with an upstanding hook for catching behind the bumper of a car;
- figure 5 shows the end terminal of the invention in a specific embodiment with an
insert beam provided in the part of the elongated beam; and
- figure 6A and figure 6B respectively show the end terminal of the invention as provided
with a deflector in rest, and after impact with a colliding car.
[0021] Whenever in the figures the same reference numerals are applied, these numerals refer
to the same parts.
[0022] Making first reference to figure 6A, this figure most clearly shows the substance
of a nominal configuration of an end terminal 1 for a safety guardrail. Such an end
terminal 1 comprises an elongated beam 2 which is on opposite ends connected to a
ground anchor 3 and to a safety guardrail, respectively. The safety guardrail is not
shown in the figure, but its construction and its combination with an end terminal
1 as shown in figure 6A is abundantly clear to the skilled person and requires no
further elucidation. The end terminal 1 comprises a collision catcher 4 which is slidably
mounted on the beam 2, wherein the collision catcher 4 connects to a sliding block
5 with an aperture 6 through which the beam 2 is guided.
[0023] Turning now to figure 1, a first aspect of the invention is illustrated by a detailed
view at the beam 2 and the sliding block 5 with its aperture 6. It is shown in figure
1 that inside the aperture 6 the sliding block 5 is provided with one or more protruding
deformation elements 7. Figure 1 only provides a view of a single deformation element
7, but it is preferred that at least two deformation elements 7 are provided within
the aperture 6 and on the sliding block 5, projecting to opposite sides of the elongated
beam 2 reaching through the sliding block 5.
[0024] Figure 2A and figure 2B show from different perspectives how the beam 2 is deformed
during a vehicle impact as the sliding block 5 is moved in the direction of arrow
A, towards the safety guardrail, along beam 2. Beam 2 may be arranged as having an
optional initial depressed portion 8 that the deformation elements 7 engage with.
This is however not necessary as the beam 2 may also be arranged with a square or
rectangular cross-section over its entire length.
[0025] There are no specific requirements as to the tensile strength of the elongated beam
2 and the tensile strength of the sliding block 5, as long as the beam 2 and the sliding
block 5 are arranged such that upon movement of the sliding block 5 along the beam
2 towards the safety guardrail - that is in the direction of the arrow A - the deformation
element or elements 7 provide a depressed portion 8 in the beam 2, or extend an initial
depressed portion 8 of the beam 2 towards the safety guardrail. As the sliding block
moves along the beam 2 during vehicle impact, the deformation elements 7 deform the
beam 2, which takes energy and slows the car down. As the elongated beam 2 has a substantially
square or rectangular cross-section before movement of the sliding block 5, after
passing of the sliding block 5 this square or rectangular cross-section is converted
by the operation of the deformation elements 7 into a non-square or non-rectangular
cross-section with depressed portions 8.
[0026] Taking reference now to figures 3A - 3C it is shown that the sliding block 5 is provided
with at least one of upper 5' wall portions inside the aperture 6. Preferably also
at least one of lower wall portions 5" are provided. This means that not both upper
5' and lower 5" wall portions need to be present, but that it is preferred that at
least one of the upper wall portions 5' and at least one of lower wall portions 5"
are provided. Whatever wall portions are actually present, these wall portions are
intended to directly engage the elongated beam 2 for support of the sliding block
5, and that in or between said at least one of upper 5' and lower 5" wall portions
a slit 9 or slits are provided providing room for passing of bolt heads 10 or other
fixtures on top of the elongated beam 2. Going from figure 3A to figure 3C the progressing
movement of the sliding block 5 along the elongated beam 2 is shown, wherein the bolt
heads 10 can pass through the upper slit 9 between the two adjacent upper wall portions
5'. A similar construction can be provided at the underside of the beam 2 wherein
a lower slit 9 can be provided between the optional lower wall portions 5". This is
not visible in the figures 3A - 3C but entirely clear for the skilled person, so that
a further elucidation is superfluous.
[0027] In an alternative embodiment shown in figure 3D an embodiment of a sliding block
5 is shown wherein the sidewalls 15', 15" of the sliding block 5 are provided with
indents 16', 16" protruding inwardly into the aperture 6 through which the elongated
beam (not shown) is guided, wherein said indents 16', 16" are designed to directly
engage the elongated beam for support of the sliding block 5 whilst providing room
for passing of bolt heads 10 or other fixtures extending from the elongated beam 2.
[0028] Turning now to figure 4A and figure 4B it shows that the collision catcher 4 has
a hook part 11. Figure 4B shows its function for catching behind a bumper 12 of a
colliding car.
[0029] Preferably the hook part 11 is upstanding, which has proven to be most effective.
It can also be beneficial that the hook part 11 is swivable. Other options are to
embody the hook part with a locking pin that breaks under impact. The hook part can
also be embodied as an active feature which becomes operational upon impact of a car.
The way this can be executed requires no further elucidation, and is therefore not
further shown in the drawing.
[0030] In figure 5 it is indicated that the elongated beam 2 is provided with an insert
beam extending over a part 13 of the length of the elongated beam 2 to provide said
elongated beam with portions of different impact resistance. As will be clear from
figure 5, the insert beam in part 13 of the elongated beam 2 is closer to the safety
guardrail (which is not shown but which is present at the left of the figure), than
to the ground anchor 3 in order to provide that upon impact the elongated beam 2 initially
provides a lower impact resistance than at a final stage when the part 13 of the elongated
beam 2, wherein the insert beam is provided, becomes operational. Although figure
5 only shows a single insert beam, it may be preferable to provide the elongated beam
2 with a plurality of insert beams, wherein the insert beams have mutually differing
lengths, gauges and/or material properties. This increases the flexibility in the
design to provide the elongated beam with portions of different impact resistance.
[0031] As another feature shown in figure 5, below the elongated beam 2 a stander 17 is
provided with a U-shaped receptacle 18 in which the elongated beam 2 is received.
Preferably the stander 17 is designed to collapse when the elongated beam 2 is loaded
during the impact of a colliding car.
[0032] Turning back to figure 6A, it is shown near to the collision catcher 4 the end terminal
is provided with a deflector 14, wherein the deflector 14 is mounted on and extends
below the elongated beam 2. Alternatively the deflector 14 can also be mounted to
the ground. Figure 6B shows the functionality of the deflector 14 to deflect parts
of the vehicle (mainly the wheel 15) back out, away from the anchor 3 to the ground,
to prevent such parts from getting wedged and trapped between the underside of the
elongated beam 2 and the rigid anchor 3 to the ground.
[0033] Although the invention has been discussed in the foregoing with reference to exemplary
embodiments of the end terminal for a safety guard of the invention, the invention
is not restricted to these particular embodiments which can be varied in many ways
without departing from the invention. The discussed exemplary embodiments shall therefore
not be used to construe the appended claims strictly in accordance therewith. On the
contrary the embodiments are merely intended to explain the wording of the appended
claims without intent to limit the claims to these exemplary embodiments. The scope
of protection of the invention shall therefore be construed in accordance with the
appended claims only, wherein a possible ambiguity in the wording of the claims shall
be resolved using these exemplary embodiments.
1. End terminal (1) for a safety guardrail, said end terminal (1) comprising an elongated
beam (2) which is on opposite ends connected to a ground anchor (3) and to the safety
guardrail, respectively, and further comprising a collision catcher (4) which is slidably
mounted on the beam (2), wherein the collision catcher (4) connects to a sliding block
(5) with an aperture (6) through which the beam (2) is guided, characterized in that inside the aperture (6) the sliding block (5) is provided with one or more protruding
deformation elements (7) that engage the beam (2) so as to arrange that upon movement
of the sliding block (5) towards the safety guardrail, the deformation elements (7)
provide a depressed portion (8) in the beam (2) that extends towards the safety guardrail.
2. End terminal according to claim 1, characterized in that the elongated beam (2) has an initial depressed portion (8) in which the one or more
protruding deformation elements (7) protrude.
3. End terminal according to claim 1 or 2, characterized in that the elongated beam (2) has a substantially square or rectangular cross-section, and
that at least two deformation elements (7) are provided within the aperture (6) on
the sliding block (5), and projecting to opposite sides of the elongated beam (2)
reaching through the sliding block (5).
4. End terminal according to the preamble of claim 1 or according to any one of claims
1 - 3, characterized in that the sliding block (5) is provided with at least one of upper (5') wall portions inside
the aperture (6) that directly engage the elongated beam (2) for support of the sliding
block (5), and that in or between said at least one of upper (5') wall portions a
slit (9) or slits are provided providing room for passing of bolt heads (10) or other
fixtures extending from the elongated beam (2).
5. End terminal according to claim 4, characterized in that the sliding block (5) is also provided with at least one of lower (5") wall portions
inside the aperture (6) that directly engage the elongated beam (2) for support of
the sliding block (5), and that in or between said at least one of lower (5") wall
portions a slit (9) or slits are provided providing room for passing of bolt heads
(10) or other fixtures extending from the elongated beam (2).
6. End terminal according to the preamble of claim 1 or according to any one of claims
1 - 5, characterized in that the sidewalls (15', 15") of the sliding block (5) are provided with indents (16',
16") protruding inwardly into the aperture (6) through which the elongated beam (2)
is guided, wherein said indents (16', 16") directly engage the elongated beam (2)
for support of the sliding block (5) whilst providing room for passing of bolt heads
(10) or other fixtures extending from the elongated beam (2).
7. End terminal according to the preamble of claim 1 or according to any one of claims
1 - 6, characterized in that the collision catcher (4) has a hook part (11) for catching behind a bumper (12)
of a colliding car.
8. End terminal according to claim 7, characterized in that the hook part (11) is an upstanding hook part.
9. End terminal according to the preamble of claim 1 or according to any one of claims
1 - 8, characterized in that below the elongated beam (2) a stander (17) is provided with a U-shaped receptacle
(18) in which the elongated beam (2) is received.
10. End terminal according to claim 9, characterized in that the stander (17) is designed to collapse when the elongated beam (2) is loaded during
the impact of a colliding car.
11. End terminal according to the preamble of claim 1 or according to any one of claims
1 - 10, characterized in that the elongated beam (2) is provided with at least one insert beam extending over a
part (13) of the length of the elongated beam (2) to provide said elongated beam (2)
with portions of different impact resistance.
12. End terminal according to claim 11, characterized in that the insert beams have mutually differing lengths, gauges and/or material properties.
13. End terminal according to any one of claims 11 - 12, characterized in that the at least one insert beam is closer to the safety guardrail than to the ground
anchor (3) in order to provide that upon impact the elongated beam (2) initially provides
a lower impact resistance than at a final stage when the part (13) of the elongated
beam (2) wherein the at least one insert beam is provided becomes operational.
14. End terminal according to the preamble of claim 1 or according to any one of claims
1 - 13, characterized in that the end terminal (1) is provided with a deflector (14), wherein the deflector (14)
extends below the elongated beam (2).
15. End terminal according to claim 14, characterized in that the deflector (14) is mounted to the ground.