U.S. patent application number 10/557389 was filed with the patent office on 2006-12-28 for security barriers.
Invention is credited to Richard David Henshell.
Application Number | 20060288643 10/557389 |
Document ID | / |
Family ID | 9958279 |
Filed Date | 2006-12-28 |
United States Patent
Application |
20060288643 |
Kind Code |
A1 |
Henshell; Richard David |
December 28, 2006 |
Security barriers
Abstract
A security barrier is disclosed for controlling the passage of
vehicles along a vehicle throughway (16). The security barrier
comprising upper and lower barrier members (20, 22, 120, 122, 220,
222, 320, 322). The upper barrier member (20, 120, 220, 320) is
pivotally mounted for movement between a closed configuration, in
which a barrier portion of said upper barrier member (20, 120, 220,
320) extends across the vehicle throughway (16), and an open
configuration in which the barrier portion is raised to permit
passage of a 10 vehicle along the vehicle throughway (16). The
upper and lower barrier members (20, 22, 120, 122, 220, 222, 320,
322) are operably linked so that pivoting of the upper barrier
member (20, 120, 220, 320) to the open configuration causes the
lower barrier member (22, 122, 222, 322) to be lowered, and
pivoting of the upper barrier member (20, 120, 220, 320) to the
closed configuration causes the lower barrier member (22, 122, 222,
322) to be raised.
Inventors: |
Henshell; Richard David;
(Nottingham, GB) |
Correspondence
Address: |
Gunnar G Leinberg;Nixon Peabody
Clinton Square
P O Box 31051
Rochester
NY
14603-1051
US
|
Family ID: |
9958279 |
Appl. No.: |
10/557389 |
Filed: |
May 17, 2004 |
PCT Filed: |
May 17, 2004 |
PCT NO: |
PCT/GB04/02112 |
371 Date: |
November 17, 2005 |
Current U.S.
Class: |
49/49 |
Current CPC
Class: |
E01F 13/06 20130101 |
Class at
Publication: |
049/049 |
International
Class: |
E01F 13/00 20060101
E01F013/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 17, 2003 |
GB |
0311385.9 |
Claims
1. A security barrier for controlling passage of vehicles along a
vehicle throughway, the security barrier comprising: upper and
lower barrier members, the upper barrier member being pivotally
mounted for movement between a closed configuration, in which a
barrier portion of said upper barrier member extends across the
vehicle throughway, and an open configuration in which the barrier
portion is raised to permit passage of a vehicle along the vehicle
throughway, the lower barrier member being mounted by at least one
pivoting linkage to a part of the security barrier that is
stationary during use, the at least one pivoting linkage being
rotatable relative to the stationary part of the security barrier
within a vertical plane that is orientated generally
perpendicularly to the direction of motion of vehicles along the
vehicle throughway, wherein the upper barrier member is operably
linked to the lower barrier member such that pivoting of the upper
barrier member to the open configuration causes the lower barrier
member to be lowered and pivoting of the upper barrier member to
the closed configuration causes the lower barrier member to be
raised.
2. A security barrier as claimed in claim 1, wherein the security
barrier is arranged so that a counterbalancing moment is exerted on
the upper barrier member in the rotational direction opposite to
that of the moment caused by the weight of the upper barrier
member.
3. A security barrier as claimed in claim 2, wherein the
counterbalance moment is predominantly caused by the weight of the
lower barrier member.
4. A security barrier as claimed in claim 3, wherein the upper
barrier member is pivotally mounted at a point between its ends,
the upper barrier member thereby comprising an extension portion
that extends to the other side of said pivot point to the barrier
portion, the extension portion of the upper barrier member being
operably linked to the lower barrier member such that the lower
barrier member acts to counterbalance the weight of the barrier
portion of the upper barrier member.
5. A security barrier as claimed in claim 4, wherein the lower
barrier member and the extension portion of the upper barrier
member are operably linked by a mechanical linkage.
6. A security barrier as claimed in claim 5, wherein the mechanical
linkage comprises a connecting member that extends between the
extension portion of the upper barrier member, and the lower
barrier member.
7. A security barrier as claimed in claim 5, wherein the mechanical
linkage comprises a connecting member that extends between the
extension portion of the upper barrier member, and an intermediate
component that is itself mechanically linked to the lower barrier
member.
8. A security barrier as claimed in claim 6, wherein the connecting
member is rigid in form, and is pivotally attached to the extension
portion of the upper barrier member.
9. A security barrier as claimed in claim 6, wherein the length of
the connecting member between the extension portion of the upper
barrier member, and either the lower barrier member or the
intermediate component, is variable such that said length increases
as the lower barrier member is lowered and decreases as the lower
barrier member is raised.
10. A security barrier as claimed in claim 9, wherein the
connecting member is flexible, and the upper barrier member
includes a cam about which the flexible member travels such that
the effective length of the connecting member is varied.
11. A security barrier as claimed in claim 1, wherein the lower
barrier member is connected by a first pivoting linkage to a pillar
or the like at the other side of the vehicle throughway to the
extension portion, the lower barrier member being suspended by
pivoting linkages from the extension portion of the upper barrier
member and the pillar at the other side of the vehicle
throughway.
12. A security barrier as claimed in claim 1, wherein the lower
barrier member is mounted by first and second pivoting linkages,
the first and second linkages being of identical length and
orientated parallel to each other such that the lower barrier
member is maintained in a horizontal orientation at all times.
13. A security barrier as claimed in claim 1, wherein the lower
barrier member is received within a channel formed in the ground
surface such that the upper surface of the lower barrier member
lies substantially flush with the ground level.
14. A security barrier as claimed in claim 1, wherein the security
barrier includes a ramp that is formed on the upper surface of the
ground across the vehicle throughway, and includes a channel within
which the lower barrier member is received such that the upper
surface of the lower barrier member lies substantially flush with
the upper surface of the ramp.
15. A security barrier as claimed in claim 14, wherein the ramp is
formed from suitable road-building materials, and the side walls of
the channel are lined, and thereby supported, by one or more
support members.
16. A security barrier as claimed in claim 1, wherein the lower
barrier member has such a form that when it is lowered into
abutment with the ground a vehicle is able to drive over it without
undue hindrance.
17. A security barrier as claimed in claim 1, wherein the lower
barrier member is of greater weight and strength than the upper
barrier member.
18. A security barrier as claimed in claim 17, wherein the
cross-sectional shape of the lower barrier member is chosen so as
to maximise the strength of the security barrier in the event of
impact by a vehicle.
19. A security barrier as claimed in claim 18, wherein the lower
barrier member is of channel section.
20. A security barrier as claimed in claim 1, wherein the upper
barrier member pivots about a fixed point in a pillar or the like
mounted to one side of the vehicle throughway, said pillar or the
like including means for rotating the upper barrier member about a
pivot axis.
21. A security barrier as claimed in claim 20, wherein the free end
of the barrier portion is received, when the upper barrier member
is in the closed configuration, within a support positioned
adjacent the opposite side of the vehicle throughway to that at
which the upper barrier member is pivotally mounted.
22. A security barrier as claimed in claim 21, wherein the upper
barrier member is pivotally mounted between two pillars at one side
of the vehicle throughway, and the free end of the upper barrier
member is received, in the closed configuration, between two
pillars at the other side of the vehicle throughway.
23. A security barrier as claimed in claim 22, wherein the lower
barrier member extends beyond both of the pillars at each side of
the vehicle throughway.
24. A security barrier as claimed in claim 23, wherein the ends of
the lower barrier member are enlarged.
25. A security barrier as claimed in claim 1, wherein the security
barrier includes a pair of portal frames that together define the
lateral limits of the vehicle throughway.
26. A security barrier as claimed in claim 25, wherein the portal
frames each define an opening, and the lower barrier member is
arranged within these openings at all times during use.
27. A security barrier as claimed in claim 1, wherein the masses of
the upper barrier member and the lower barrier member are selected
so as to conserve gravitational potential energy between the closed
and open configurations.
28. A security barrier as claimed in claim 1, wherein the lower
barrier member is suspended beneath two upper barrier members that
are each pivotally mounted on a pillar or the like and are directed
towards each other.
29. A method for making a security barrier for controlling passage
of vehicles along a vehicle throughway, the method comprising:
pivotally mounting at least one upper barrier member for movement
between a closed configuration and an open configuration; and
mounting at least one lower barrier member with at least one
pivoting linkage to a part of the security barrier that is
stationary during use, the at least one pivoting linkage being
rotatable relative to a base; wherein the upper barrier member is
operably linked to the lower barrier member such that pivoting of
the upper barrier member to the open configuration causes the lower
barrier member to be lowered and pivoting of the upper barrier
member to the closed configuration causes the lower barrier member
to be raised.
30. A security barrier for controlling passage of vehicles along a
vehicle throughway, the security barrier comprising: two or more
upper barrier members; at least one lower barrier member; the two
or more upper barrier members are each pivotally mounted for
movement between a closed configuration, in which a barrier portion
of each of the two or more upper barrier members extends across at
least a portion of the vehicle throughway, and an open
configuration in which the barrier portion of each of the two or
more upper barrier members is raised to permit passage of a vehicle
along the vehicle throughway, the lower barrier member is mounted
by at least one pivoting linkage to a part of the security barrier
that is stationary during use, the at least one pivoting linkage is
rotatable relative to the stationary part of the security barrier
within a vertical plane that is orientated generally
perpendicularly to the direction of motion of vehicles along the
vehicle throughway, wherein the two or more upper barrier members
are operably linked to the lower barrier member such that pivoting
of the two or more upper barrier members to the open configuration
causes the lower barrier member to be lowered and pivoting of the
two or more upper barrier members to the closed configuration
causes the lower barrier member to be raised.
Description
[0001] This invention relates to security barriers for controlling
the access of vehicles along a vehicle throughway, and in
particular to security barriers that include a pivoted barrier
member.
[0002] There are many different forms of security barrier for
controlling the access of vehicles along a vehicle throughway. One
form of security barrier includes a drive assembly situated at one
side of the vehicle throughway, and a barrier member pivotally
mounted at one end to the drive assembly. In a closed configuration
of the security barrier, the barrier member extends across the
width of the vehicle throughway. In the closed configuration, the
barrier member is orientated horizontally at a height above ground
level that prevents the access of vehicles along the vehicle
throughway. In order to allow vehicular access, the security
barrier is moved into an open configuration by rotating the barrier
member about its pivot until the barrier member is in a vertical
orientation. Security barriers of this type are popular due to the
relatively low cost of manufacture and installation, and high speed
of operation.
[0003] A principal disadvantage associated with security barriers
of this type is that, in order to provide a high level of security,
the barrier member needs to have a high level of strength.
Unfortunately, the stronger the barrier member, the more the
barrier member generally weighs, and consequently the greater the
power and time required to rotate the barrier member from a
horizontal orientation to a vertical orientation. For this reason,
conventional security barriers of this type do not generally
provide a high level of security.
[0004] In order to attempt to overcome this disadvantage, security
barriers have been developed that incorporate additional security
features, such as bollards that rise out of the ground. However,
such additional security features typically lower the speed of
operation significantly. In addition, the cost of manufacturing and
installing the security barrier is likely to be increased
considerably.
[0005] There has now been devised an improved security barrier
which overcomes or substantially mitigates the above-mentioned
and/or other disadvantages associated with the prior art.
[0006] According to the invention, there is provided a security
barrier for controlling passage of vehicles along a vehicle
throughway, the security barrier comprising upper and lower barrier
members, the upper barrier member being pivotally mounted for
movement between a closed configuration, in which a barrier portion
of said upper barrier member extends across the vehicle throughway,
and an open configuration in which the barrier portion is raised to
permit passage of a vehicle along the vehicle throughway, wherein
the upper barrier member is operably linked to the lower barrier
member such that pivoting of the upper barrier member to the open
configuration causes the lower barrier member to be lowered and
pivoting of the upper barrier member to the closed configuration
causes the lower barrier member to be raised.
[0007] The security barrier according to the invention is
advantageous principally because the provision of two barrier
members increases the level of security provided by the security
barrier without significantly increasing the cost of manufacture
and installation. The lower barrier member of the invention is
preferably used as a counterbalancing weight for the barrier
portion of the upper barrier member, thereby reducing the power and
time required to raise the barrier portion. The lower barrier
member may therefore be formed in materials of greater weight and
strength relative to the upper barrier member.
[0008] The upper barrier member is preferably pivotally mounted at
a point between its ends. Hence, the upper barrier member
preferably comprises the barrier portion that extends across the
vehicle throughway, and an extension portion that extends to the
other side of said pivot point. The extension portion of the upper
barrier member is preferably operably linked to the lower barrier
member such that the lower barrier member acts to counterbalance
the weight of the barrier portion of the upper barrier member.
[0009] The lower barrier member, and the extension portion of the
upper barrier member, are preferably operably linked by a
mechanical linkage. The mechanical linkage preferably comprises a
connecting member, which may be either rigid or flexible in form,
that extends between the extension portion of the upper barrier
member, and either the lower barrier member itself or an
intermediate component that is itself mechanically linked to the
lower barrier member.
[0010] Where the connecting member is rigid, the connecting member
is preferably pivotally attached at one end to the extension
portion of the upper barrier member, and attached to the lower
barrier member at the other end. The rigid connecting member may
also be pivotally attached to the lower barrier member.
[0011] In other embodiments, the length of the connecting member
between the extension portion of the upper barrier member, and
either the lower barrier member or the intermediate component, is
variable. In particular, said length preferably increases as the
lower barrier member is lowered and decreases as the lower barrier
member is raised. In this case, the connecting member is preferably
flexible, and the upper barrier member preferably includes a cam
about which the flexible member travels such that the effective
length of the connecting member varies as described above. The cam
is preferably shaped so as to optimise the balance between the
weight of the barrier portion, and the weight of the lower barrier
member.
[0012] Most preferably, the lower barrier member is of greater
weight and strength than the upper barrier member. The upper
barrier member preferably pivots about a fixed point in a pillar or
the like mounted to one side of the vehicle throughway. Such a
pillar or the like preferably includes means for rotating the upper
barrier member about the pivot axis. Such means may be manually
operated, or may be driven by a motor. In the latter case, the
means may be actuated by an operator or automatically under
microprocessor control. For example, a microprocessor may cause the
upper barrier member to be raised to the open configuration in
response to a satisfactory security check. The security check may
be performed in any conventional manner. For example, the security
barrier may include a device for receiving security information,
such as a keycard reader, microphone or keypad, and means for
verifying the security information before activating the rotating
means.
[0013] The free end of the barrier portion is preferably received,
when the upper barrier member is in the closed configuration,
within a support positioned adjacent the opposite side of the
vehicle throughway to that at which the upper barrier member is
pivotally mounted. Conveniently, such a support takes the form of a
well in the upper surface of a pillar or the like that is mounted
at that side of the vehicle throughway, or a ledge formed on such a
pillar or between two pillars.
[0014] In a particularly preferred arrangement, the upper barrier
member is pivotally mounted between two pillars at one side of the
vehicle throughway, and the free end of the upper barrier member is
received, in the closed configuration, between two pillars at the
other side of the vehicle throughway.
[0015] The lower barrier member is preferably mounted by means of
at least one pivoting linkage to a part of the security barrier
that is stationary during use. The first pivoting linkage is
preferably pivotally attached at one end to the lower barrier
member, and at the other end to a part of the security barrier that
is stationary during use. Said stationary part of the security
barrier is preferably situated at the other side of the vehicle
throughway to the extension portion of the upper barrier member.
Where the lower barrier member is mounted by means of only one
pivoting linkage, the pivoting linkage is preferably pivotally
attached to a part of the security barrier that is situated above
ground level.
[0016] For example, the lower barrier member may be connected by
the pivoting linkage to a pillar or the like at that side of the
vehicle throughway, which pillar may also be part of an assembly
that receives and supports the free end of the upper barrier member
when the latter is in the closed configuration. In this case, the
lower barrier member is preferably suspended by pivoting linkages
from the extension portion of the upper barrier member and the
pillar at the other side of the vehicle throughway. In such an
arrangement, in the closed configuration, the upper and lower
barrier members and the two pivoting linkages by which the lower
barrier member is suspended have a generally trapezoidal
disposition, with the upper and lower barrier members preferably
being disposed substantially parallel to each other and to the
ground. By appropriate selection of the geometry of the linkages,
an arrangement can be achieved in which the lower barrier member
remains horizontal and parallel to the ground while it is lowered
or raised by raising or lowering of the upper barrier member to the
open or closed configuration.
[0017] In addition, the lower barrier member may be mounted by
means of a second pivoting linkage to a further part of the
security barrier that is stationary during use. The second pivoting
linkage is preferably pivotally attached at one end to the lower
barrier member, and at the other end to a part of the security
barrier that is stationary during use. In particular, the second
pivoting linkage is preferably pivotally attached to a part of the
security barrier that is situated on the same side of the vehicle
throughway as the extension portion of the upper barrier member. In
this case, the first and second pivoting linkages preferably act on
opposite ends of the lower barrier member.
[0018] The first and second pivoting linkages are preferably
pivotally attached to a part of the security barrier that is at
ground level. Most preferably, the first and second linkages are of
identical length, and are orientated parallel to each other, such
that the lower barrier member is maintained in a horizontal
orientation at all times.
[0019] In the closed configuration, the upper barrier member
extends across the vehicle throughway and represents a barrier to a
vehicle travelling along the vehicle throughway. The lower barrier
member is suspended beneath the upper barrier member and also
extends across the vehicle throughway, above ground level.
[0020] When the upper barrier member is raised to the open
configuration, the lower barrier member is lowered sufficiently to
permit a vehicle to pass over it. The lower barrier member may be
received within a channel formed in the ground surface such that
the upper surface of the lower barrier member lies substantially
flush with the ground level. The security barrier may include a
ramp that is formed on the upper surface of the ground across the
vehicle throughway, and includes a channel within which the lower
barrier member may be received such that the upper surface of the
lower barrier member lies substantially flush with the upper
surface of the ramp. The ramp is preferably formed from suitable
road-building materials, such as asphalt or concrete, and the side
walls of the channel are preferably lined, and thereby supported,
by one or more support members. These support members may also
provide a suitable substrate for the pivoting attachment of any
linkages.
[0021] Alternatively, the lower barrier member may have such a form
that when it is lowered into abutment with the ground a vehicle is
able to drive over it without undue hindrance. The lower barrier
member may, for example, be formed with ramps at one or both sides.
In such an arrangement, the lower barrier member may permit traffic
flow only in one direction, or may permit traffic flow while at the
same time having a speed-restricting (or traffic-calming) effect.
Alternatively, the lower barrier member may change in form when it
is lowered into engagement with the ground. For instance, elements
of the lower barrier member that are disposed, in the closed
configuration, perpendicular to the ground, may be hinged such that
they rotate to parallel alignment with the ground.
[0022] The lower barrier member is preferably formed of a high
strength material. The cross-sectional area of the lower barrier
member is preferably greater than that of the upper barrier member
so as to provide increased strength. The cross-sectional shape of
the lower barrier member is preferably chosen so as to maximise the
strength of the barrier in the event of impact by a vehicle. For
example, the lower barrier member may be of channel section, and
hence comprise a plate that is orientated in a horizontal plane and
a pair of downwardly-depending side plates that are both orientated
in vertical planes. In addition, the lower barrier member may
include a high-strength cable along its length to provide
additional strength in the event of an impact.
[0023] The lower barrier member preferably extends beyond one, or
preferably, both of the pillars or the like at each side of the
vehicle throughway. This will help to impede any attempt by a
vehicle to gain access at either side of the security barrier. The
lower barrier member is preferably adapted to deform when impacted
by an oncoming vehicle so as to absorb the energy of impact and
contain the vehicle on one side of the security barrier without
breaking. In order to further strengthen the security barrier on
impact by a vehicle, the ends of the lower barrier member are
preferably enlarged.
[0024] The security barrier may include a pair of portal frames
that together define the lateral limits of the vehicle throughway.
Preferably, the portal frames each define an opening, and the lower
barrier member is preferably arranged within these openings at all
times during use. In this case, the portal frames provide an
additional reinforcement in the event of a vehicle colliding with
the lower barrier member.
[0025] The security barrier is preferably arranged so that a
counterbalancing moment is exerted on the upper barrier member in
the rotational direction opposite to that of the moment caused by
the weight of the upper barrier member. Preferably, the
counterbalance moment is predominantly caused by the weight of the
lower barrier member.
[0026] Preferably, in order to minimise the energy required to
raise and lower the upper barrier member between the closed and
open configurations, the masses of the upper barrier member and the
lower barrier member are selected so as to conserve gravitational
potential energy between the closed and open positions. In
approximate terms, this is achieved by equating the weight of the
lower barrier member multiplied by the height through which its
centre of gravity moves, to the weight of the upper barrier member
multiplied by the height through which its centre of gravity
moves.
[0027] In the majority of applications, the upper barrier member
will have a length of less than 10 m, more typically less than 5 m,
eg about 3-4 m. This will be sufficient for the majority of
installations. However, where the vehicle throughway is
particularly wide, it may be necessary to achieve an effective
barrier width in excess of these figures, possibly as much as 20 m
or more. In such cases, it may be appropriate for two (or more)
upper barrier members to be operably linked to the lower barrier
member. In a particularly preferred arrangement, the lower barrier
member is suspended beneath two upper barrier members that are each
pivotally mounted on a pillar or the like and are directed towards
each other. The arrangement is thus essentially symmetrical and
potentially offers a number of advantages, as follows:
[0028] a) the upper barrier members may be shorter in length than
would be the case for a single upper barrier member spanning the
same distance. This may lead to faster operation and/or fewer
problems in high winds;
[0029] b) The presence of two motors, one associated with each
upper barrier member may speed operation of the barrier, especially
where the lower barrier member is particularly heavy;
[0030] c) Provided that the two upper barrier members are moved in
synchronism, the lower barrier member will always remain horizontal
when it is lowered.
[0031] The invention will now be described in greater detail, by
way of illustration only, with reference to the accompanying
drawings, in which
[0032] FIG. 1 is a plan view of a vehicle throughway and a first
embodiment of a security barrier according to the invention in a
closed configuration;
[0033] FIG. 2 is a cross-sectional view, along the line II-II in
FIG. 1, of the security barrier in a closed configuration;
[0034] FIG. 3 is a cross-sectional view of the security barrier in
a partially open configuration;
[0035] FIG. 4 is a cross-sectional view of the security barrier in
a fully open configuration; and
[0036] FIG. 5 is a cross-sectional view of a second embodiment of a
security barrier according to the invention in a closed
configuration;
[0037] FIG. 6 is a cross-sectional view of a third embodiment of a
security barrier according to the invention in a closed
configuration;
[0038] FIG. 7 is a cross-sectional view of the third embodiment in
a partially open configuration;
[0039] FIG. 8 is a cross-sectional view of a fourth embodiment of a
security barrier according to the invention in a closed
configuration; and
[0040] FIG. 9 is a cross-sectional view, which is orthogonal to the
view of FIG. 8, of a lower barrier member and a ramp that both form
part of the fourth embodiment.
[0041] FIGS. 1 and 2 show a security barrier according to the
invention in a closed configuration. The security barrier comprises
a drive assembly 12 and a slave assembly 14. The drive and slave
assemblies 12, 14 are positioned on opposite sides of a vehicle
throughway 16, and each comprise a pair of spaced-apart rectangular
pillars. Vehicles move along the vehicle throughway 16 in the
direction of the arrows in FIG. 1 (and/or the opposite
direction).
[0042] The security barrier further comprises an upper barrier
member 20 which is securely mounted, a short distance from one end
of the member 20, about a drive axle 13 that extends between the
upper ends of the pillars of the drive assembly 12. When the
security barrier is in its closed configuration, the end of the
upper barrier member 20 remote from the drive axle 13 rests upon a
support platform 15 that extends between the upper ends of the
pillars of the slave assembly 14.
[0043] The drive assembly 12 also includes means (not shown in the
Figures) for imparting a rotational force on the drive axle 13.
Such means could, for instance, comprise a hand-wheel that is
rotated manually by an operator or, alternatively, an electric
motor that is controlled either directly by an operator or
automatically by a central processor. Where a motor rotates the
drive axle 13, the motor is preferably enclosed within a pillar of
the drive assembly 12. However, it will be clear to the skilled
person that any means could be used that is capable of imparting
sufficient rotational force upon the drive axle 13 to raise the
upper barrier member 20 into a vertical orientation.
[0044] The security barrier further comprises a lower barrier
member 22 which is of greater weight and strength than the upper
barrier member 20. The lower barrier member 22 extends between the
drive and slave assemblies 12, 14 directly below, and (in the
closed configuration depicted in FIGS. 1 and 2) parallel to, the
upper barrier member 20. The lower barrier member 22, however, is
longer than the upper barrier member 20 and extends beyond both the
drive and slave assemblies 12, 14.
[0045] The lower barrier member 22 is suspended from the upper
barrier member and the slave assembly 14 respectively by first and
second links 24,26. The first link 24 is pivotally connected at one
end to the end of the upper barrier member 20 adjacent the drive
axle 13. The other end of the first link 24 is connected to a part
of the lower barrier member 22 that is situated within the drive
assembly 12. In the embodiment illustrated, the lower end of the
first link 24 is fixedly connected to the lower barrier member 22,
at right angles thereto. The first link 24 is orientated vertically
when the security barrier is in a closed configuration. In other
embodiments, the lower end of the first link 24 may be pivotally
connected to the lower barrier member 22, in which case the first
link 24 will be inclined to the vertical when the security barrier
is in the closed configuration. The pivotal connection is formed so
that the upper barrier member 20 is rotatable relative to the lower
barrier member 22 and the first link 24, within the limits imposed
by the remainder of the security barrier, in a vertical plane which
is orientated perpendicularly to the direction of motion of
vehicles along the vehicle throughway 16.
[0046] The second link 26 is pivotally connected at one end to a
pillar of the slave assembly 14 and at the other end to a part of
the lower barrier member 22 that is positioned between the drive
and slave assemblies 12, 14 in the closed configuration. The second
link 26 is orientated at an angle to both the pillar of the slave
assembly 14 and the lower barrier member 22. The pivotal
connections are formed so that the second link 26 is rotatable
relative to both the pillar of the slave assembly 14 and the lower
barrier member 22, within the limits imposed by the remainder of
the security barrier, in a vertical plane which is orientated
perpendicularly to the direction of motion of vehicles along the
vehicle throughway 16.
[0047] Referring also now to FIGS. 3 and 4, the security barrier is
arranged so that if the drive axle 13 is rotated anti-clockwise (as
viewed in FIGS. 2 to 4), and the upper barrier member 20 is
therefore raised, the lower barrier member 22 is lowered, as shown
in FIG. 3. As shown in FIGS. 3 and 4, the first link component 24
remains orientated vertically, the lower barrier member 22 remains
orientated horizontally, and the second link component 26 rotates
towards a vertical orientation, as the lower barrier member 22 is
lowered. A trough 30 is formed across the vehicle throughway in a
straight line between, and slightly beyond, the drive and slave
assemblies 12, 14 so that when the upper barrier member 20 is
raised fully, as shown in FIG. 4, the lower barrier member 22 is
received within the trough 30, the upper surface of the lower
barrier member 22 being substantially flush with the surface of the
vehicle throughway.
[0048] In order to further strengthen the security barrier in the
event of an impact by a vehicle, the lower barrier member 22 has
enlarged end portions 23 that are of larger dimensions than the
space between the pillars of the drive and slave assemblies 12, 14.
The trough 30 includes enlarged end portions 32 so as to
accommodate the enlarged portions 23 of the lower barrier member
22.
[0049] In the closed configuration of the security barrier, a
counterbalance moment is exerted by the first link 24 upon the end
of the upper barrier member 20 to which the first link 24 is
pivotally connected. The counterbalance moment is caused by the
resultant force exerted by the first link 24 upon the end of the
upper barrier member 20. The analysis of the forces in the various
links is amenable to simple static analysis for slow motion or to
dynamic analysis in the case where motion is fast enough for
inertia forces to be significant. The lengths, spatial orientation,
speed of operation and masses of the links can be adjusted to
achieve a wide variety of predictable resulting effects.
[0050] The security barrier is arranged so that, as the upper
barrier member 20 is rotated from the closed configuration, in
which the barrier moment is greater than the counterbalance moment,
towards the open configuration, the counterbalance moment increases
relative to the barrier moment. The security barrier will then
reach an equilibrium configuration, situated between the closed and
open configurations, in which the counterbalance moment is equal to
the barrier moment. As the upper barrier member 20 is rotated
further, from the equilibrium configuration towards the open
configuration, the counterbalance moment increases further relative
to the barrier moment and becomes greater than the barrier moment.
In this way, a rotational force is required to rotate the upper
barrier member 20 from the closed configuration to the equilibrium
configuration but then the counterbalance moment will overcome the
barrier moment to rotate the upper barrier member 20 from the
equilibrium configuration to the open configuration. A
counterbalance mass (not shown in the Figures) may be added to the
end of the upper barrier member 20 adjacent the first link 24 so as
to adjust the barrier and counterbalance moments, as required.
[0051] In order to minimise the energy required to raise and lower
the upper barrier member 20 between the closed and open
configurations, the masses of the upper barrier member 20 and the
lower barrier member 22 are selected so as to conserve
gravitational potential energy between the closed and open
positions. In approximate terms, this is achieved by equating the
weight of the lower barrier member 22 multiplied by the height
through which its centre of gravity moves, to the weight of the
upper barrier member 20 multiplied by the height through which its
centre of gravity moves.
[0052] FIG. 5 shows a second embodiment of a security barrier
according to the invention. The second embodiment differs from the
first, illustrated in FIGS. 1 to 4, in that it comprises a single
lower barrier member 122 that is suspended, not from a single upper
barrier member and a slave assembly, but instead from a pair of
upper barrier members 120. The upper barrier members 120 are
broadly similar to the upper barrier member 20 of the first
embodiment, each being pivotally mounted in a drive assembly 112
that houses a motor (not shown) by which the upper barrier member
120 can be rotated (about drive axles 113) from the closed
configuration shown in FIG. 5 (in which the upper barrier member
120 is disposed substantially horizontally, in the path of a
vehicle approaching the security barrier) to an open configuration
(in which the upper barrier member 120 is raised to permit passage
of the vehicle). As for the first embodiment, each drive assembly
112 comprises a pair of spaced-apart pillars, the upper barrier
members 120 being mounted between the two pillars of the drive
assembly 112.
[0053] The upper barrier members 120 are coupled to the lower
barrier member 122 by pivoting links 124, each of which is
connected at one end to a point near the end of the upper barrier
member 120 adjacent the associated drive assembly 112 and at the
other end to the lower barrier member 122. As can be seen from FIG.
5, the arrangement is symmetrical, with the two upper barrier
members 120 meeting at the centre of the barrier. In other
embodiments, the ends of the upper barrier members may overlap, eg
by virtue of having cranked ends or by being slightly offset from
one another.
[0054] In use, the upper barrier members 120 are raised to the open
configuration by operation of the motors housed within the drive
assemblies 112. This has the effect of lowering the lower barrier
member 122. Provided that, as would normally be the case, the two
motors are operated in synchronism, the symmetry of the barrier is
maintained as the upper barrier members 120 are raised, and the
lower barrier member 122 remains horizontal as it descends. As for
the first embodiment, the lower barrier member 122 is received
within a trough 130 formed in the ground beneath the barrier,
enlarged end portions 123 of the lower barrier member 122 being
received within correspondingly enlarged portions 132 of the trough
130.
[0055] FIGS. 6 and 7 show a third embodiment of a security barrier
according to the invention. The third embodiment is identical to
the first embodiment save for a pair of base links 226 which
replace the second link 26, and a pair of support members that line
the trough 230 along its side faces.
[0056] The base links 226 are of identical length, and are each
pivotally connected at one end to a side face of the lower barrier
member 222 and at the other end to one of the support members
within the trough 230. The security barrier is arranged so that the
base links 226 are always parallel relative to one another, and the
lower barrier member 222 is maintained in a horizontal
orientation.
[0057] When the security barrier is in its closed configuration, as
shown in FIG. 6, the lower barrier member 222 is orientated
horizontally in a raised position, and the base links 226 are
inclined relative to both the lower barrier member 222 and the
trough 230. As the upper barrier member 220 is rotated towards an
open configuration, the lower barrier member 222 is lowered and the
base links 226 rotate towards the trough 230, as shown in FIG. 7.
When the security barrier has reached its fully open configuration,
the lower barrier member 222 and the base links 226 will lie
alongside one another within the trough 230.
[0058] The base link 226 arrangement of this embodiment ensures
that the lower barrier member 222 does not deviate from a
horizontal orientation during opening or closing of the security
barrier.
[0059] FIGS. 8 and 9 show a fourth embodiment of a security barrier
according to the invention. The fourth embodiment comprises drive
and slave assemblies 312,314 that are similar to those of the first
embodiment. The fourth embodiment also comprises a trough 330 of
rectangular cross-section. This trough 330 is similar to the trough
230 of the first embodiment except that it is formed within a ramp
334 that traverses the vehicle throughway, as shown in FIG. 9. The
ramp 334 is formed of a suitable road-building material, such as
asphalt or concrete, and L-shaped support members 336 support the
side walls of the trough 330.
[0060] An upper barrier member 320 extends in a horizontal
orientation between the drive and slave assemblies 312,314 when the
security barrier is in a closed configuration, as shown in FIG. 8.
At one end, the upper barrier member is formed with a cam 316 on
its upper surface that is securely attached to a drive axle 313.
The rotating means of the drive assembly 312 acts to rotate the
drive axle 313, and hence also the cam 316 and the upper barrier
member 320, between a closed configuration of the security barrier
in which the upper barrier member is orientated horizontally and a
fully open configuration of the security barrier in which the upper
barrier member is orientated vertically. In the closed
configuration of the security barrier, the upper barrier member 320
rests upon a platform 315 extending between the two pillars of the
slave assembly 314.
[0061] The fourth embodiment also has a lower barrier member 322
which has a cross-section that is rectangular and channel-shaped,
and a pair of upstanding end portions. In particular, the lower
barrier member 322 comprises an upper plate, which is orientated in
a horizontal plane, and a pair of downwardly-depending side plates
that are both orientated in vertical planes, as shown most clearly
in FIG. 9. When the security barrier is in its open configuration,
the lower barrier member 322 is accommodated within the trough 330.
The lower barrier member 322 is formed so that, in this
configuration, the upper plate forms a bridge across the trough 330
so that vehicles can drive smoothly over the ramp 334, the trough
330 and the lower barrier member 322.
[0062] In a similar manner to the third embodiment, base links 326
connect the lower barrier member 322 to one of the support members
336 within the trough 330. The base links 326 are of identical
length, and are each pivotally connected at one end to a side face
of the upstanding end portions of the lower barrier member 322 and
at the other end to one of the support members 336 within the
trough 330. The security barrier is arranged so that the base links
326 are always parallel relative to one another, and the lower
barrier member 322 is maintained in a horizontal orientation.
[0063] A wire rope 317 is securely attached at one end to the side
of the cam 316 that faces in the direction of the slave assembly
314. The wire rope 317 passes over the upper surface of the cam
316, and extends downwardly below the upper barrier member 320. An
eye at the lower end of the wire rope 317 engages a trunnion bolted
to the base link 326 that is adjacent to the drive assembly 312.
The security barrier is arranged such that the wire rope 317 acts
to raise the base link 326 that is adjacent to the drive assembly
312, and hence raise the lower barrier member 322, as the upper
barrier member 320 is lowered from the open configuration of the
security barrier to the closed configuration.
[0064] When the security barrier is in its closed configuration, as
shown in FIG. 8, the lower barrier member 322 is orientated
horizontally in a raised position, and the base links 326 are
inclined relative to both the lower barrier member 322 and the
trough 330. As the upper barrier member 320 is rotated towards an
open configuration, the lower barrier member 322 is lowered and the
base links 326 rotate towards the trough 330. When the security
barrier has reached its fully open configuration, the lower barrier
member 222 is fully accommodated within the trough 330, as
described above with reference to FIG. 9.
[0065] The shape of the cam 316 is chosen so as to give the best
possible balance at the drive axle 313 as the security barrier is
being opened or closed. The cam 316 shown in FIG. 8 has a curved
upper surface that has a gradually decreasing radius as the wire
rope 317 extends towards the base link 326 to which the wire rope
317 is attached.
[0066] Finally, the fourth embodiment includes a pair of portal
frames 340 that together define the lateral limits of the vehicle
throughway. The portal frames 340 each define an opening, and the
lower barrier member 322 is arranged within these openings at all
times during use. The portal frames 340 therefore provide an
additional reinforcement in the event of a vehicle colliding with
the lower barrier member 322. Each portal frame 340 is formed from
members that have a cross-section that is rectangular and
channel-shaped for additional strength. In addition, the portal
frames 340 need only be high enough to accommodate the lower
barrier member 322 in its uppermost position.
* * * * *