Security barrier

Abstract

The security barrier (10, figure 1) comprises a support (14, figure 1) and a barrier member (12, figure 1) which is pivotable relative to the support between a stowed position and a deployed position about a horizontal barrier pivot axis 15. The support has an upper part for positioning, in use, substantially at ground level, and the barrier pivot axis is substantially at the upper part. A main drive device 34 is operable to provide said pivotable movement of the barrier member relative to the support via an actuation device 33 having at least one pivotable member 40 which is pivotable about a respective axis of rotation parallel to the barrier pivot axis. Also disclosed is a main drive device for lifting and / or rotating a barrier member of a security barrier, an auxiliary drive unit for a security barrier having a main drive device and a method of operating a security barrier comprising a support and a barrier member.

Description

Technical Field The invention relates to a security barrier, a drive device, an auxiliary drive unit, and a method for operation thereof. Background A security barrier may be used for resisting an unauthorised passage of a vehicle such as a car or lorry. Such barriers typically comprise a housing with a barrier member mounted to it. The housing is typically cast into concrete foundations below ground level. The barrier member is arranged to be retractable so that it can be stowed within the housing to allow the vehicle to pass, or deployed to a working position above ground level to prevent or inhibit the vehicle to pass. In the deployed position the barrier member is required to be sufficiently high above ground level to prevent or inhibit the vehicle from passing. Security barriers are typically provided in two categories. The first category is a high security barrier, or anti-terrorist barrier, that is intended to prevent a vehicle from passing. Such a barrier is robustly constructed and is typically about 1 to 1.2 metres above ground level. A high security barrier might be used at a road entrance to an airport or an official building, such as a Government building, and is typically able to withstand a crash impact from a car or lorry. The second category of security barrier might be used at a home or work premises to safeguard a car parking space or driveway from being used by an unauthorised vehicle. Such barriers are relatively less robustly constructed, and typically extend to about one metre above ground level. It is known to provide a high security barrier comprising a wedge-shaped barrier member which is arranged to pivot substantially at ground level about an apex of the wedge. The barrier member is typically the width of a road and is operable to be stowed in a housing in the ground so that a surface of the wedge is level with the ground. The security member may be deployed above ground so that an uppermost part of the wedge is up to a height of 1.2 metres. Such a security barrier has the problem that when the wedge is stowed in the ground, a deep foundation is required for the housing. It will be appreciated that the depth of the foundation must be at least as deep as the height that the wedge-shape barrier member protrudes from the ground when in the deployed position. Using such a deep foundation is disadvantageous, particularly in an urban environment, because it may interfere with services such as power lines, drains, or communication cables. In another known arrangement the wedge portion of the high security barrier comprises four wedge portions that are nested together in the stowed position to reduce the depth of the barrier in the ground. Each of the four wedge portions are arranged to pivot substantially at ground level about an apex of the wedge, and when they are in the deployed position the four wedge portions form the complete wedge. Typically, the four wedge portions are moved between the stowed and the deployed position using a screw jack. A problem with such an arrangement is that the operation of the screwjack creates a partial vacuum, which draws water and debris into the mechanism thereof. The screw jack typically has seals on an output shaft, which often fail and require replacement, and results in increased operational costs and downtime for the security barrier. Overall, the known screw jack arrangement for operating the wedge barrier may be relatively unreliable. Alternatively, a hydraulic cylinder may be used instead of the screwjack to provide the required operation of the security barrier. However, a hydraulic cylinder may also be disadvantages because it requires periodic maintenance, and it may leak causing the spillage of hydraulic fluid. It is broadly an object of the present invention to address one or more of the above mentioned disadvantages of previously known security barriers. Summary What is required is a way of providing a security barrier to be deployed and retracted, which may reduce or minimise at least some of the above-mentioned problems. According to a first aspect of the invention, there provided a security barrier comprising a support and a barrier member which is pivotable relative to the support between a stowed position and a deployed position about a horizontal barrier pivot axis, the support having an upper part for positioning substantially at ground level, the barrier pivot axis being substantially at the upper part, wherein a drive device is operable to provide said pivotable movement of the barrier member relative to the support via an actuation device having at least one pivotable member which is pivotable about a respective axis of rotation parallel to the barrier pivot axis. Such a security barrier provides the advantage that the barrier member can be located shallowly in the ground in the stowed position while facilitating rapid deployment via rotary action. In an embodiment, the at least one pivotable member includes an actuation member operable to engage the barrier member for movement thereof. Preferably, the actuation member is an elongate member coupled at a distal end thereof to the barrier member by a first rotational coupling defining a first axis of rotation, whereby the actuation member is rotatable relative to the barrier member about the first axis of rotation. An advantage is to facilitate rapid deployment the barrier member via rotary action. Furthermore, a mechanical advantage may be proved. In an embodiment, the actuation member is arranged to be rotatable relative to the support. An advantage is to facilitate rapid deployment the barrier member via rotary action. Preferably, the at least one pivotable member includes a rotational drive member operable to engage the actuation member for movement thereof. Preferably, the rotational drive member is fixedly mounted for rotation on a drive shaft for providing said pivotable movement, the drive shaft defining a second axis of rotation. An advantage is to facilitate rapid deployment the barrier member via rotary action. In an embodiment, the actuation member is an elongate member coupled at a proximal end thereof to the rotational drive member by a second rotational coupling defining a third axis of rotation, whereby the actuation member is rotatable relative to the rotational drive member about the third axis of rotation. An advantage is that the actuation member can act upon a distal point on the pivotable barrier member, thereby facilitating rapid deployment the barrier member via rotary action. Preferably, the third axis of rotation is spaced apart on the rotational drive member from the second axis of rotation, whereby the rotational drive member is operable for rotating and / or lifting the actuation member in response to rotation of the rotational drive member. An advantage is that the rotational drive member simultaneously causes both lifting and rotation of the, thereby facilitating rapid pivoting of the barrier member and thus its deployment. Preferably, the first axis of rotation, the second axis of rotation and / or the third axis of rotation is parallel to the barrier pivot axis. As distinct from a system involving a screw jack, this embodiment provides an efficient arrangement by which rotary motion is transferred to the pivotable barrier member, facilitating rapid deployment the barrier member via rotary action. Preferably, the actuation device includes a transmission operable to receive driving motion from the drive device and to transmit rotational motion to at least one pivotable member. Preferably, the drive shaft is the output shaft of the transmission. Such an embodiment provides efficient transferred of rotary motion to the pivotable barrier member, facilitating rapid deployment the barrier member via rotary action. In an embodiment, one or more of the pivotable members has a first bearing surface and the support has a second bearing surface, said bearing surfaces arranged to abut each other when the barrier member is in the deployed position. An advantage is to limit the amount of rotary motion during deployment, facilitating relatively high-speed rotation and ensuring that other components are not unduly stressed at the end of travel. Such an arrangement has the advantage of inhibiting the barrier member from being forced from the support in the event of a crash impact by a vehicle. Such an arrangement also provides a stop so that the barrier member is fully deployed in a particular position. Preferably, the first bearing surface is disposed on the rotational drive member. Preferably, the rotational drive member includes a radially extending projection, and the first bearing surface comprises a non-circumferential surface of the projection. An advantage is that the rotational drive member can be simply manufactured with a robust part for blocking further rotation upon abutment. In an embodiment, the transmission includes one or more gears configured such that, in response to motion received at an input component of the transmission, for conversion into said pivotable movement of the barrier member, the output shaft of the transmission and / or said rotational drive member rotates, in use, by a total angle that (i) is less than 300 degrees, (ii) is less than 270 degrees, (ii) is 260 degrees. An advantage is that the transmission can be provided with suitable gear ratios such that a relatively small amount of angular movement of the rotational drive member is necessary, thereby facilitating rapid deployment the barrier member via rotary action. Preferably, said total angle extends between a start point of pivoting motion and the point at which said bearing surfaces abut each other. An advantage is to reduce or minimise the angular movement required. In an embodiment, at least one of the bearing surfaces is disposed on at least one plate forming part of or connected to a pivotable member or the support. An advantage is that the members with the bearing surfaces can be simply manufactured with a robust part for blocking further rotation upon abutment. In an embodiment, the actuation member and / or the rotational drive member is a plateshaped member, and / or lies, in use, in a plane perpendicular to the barrier pivot axis. An advantage is that the members are relatively lightweight components (facilitating rapid movement), and can be spaced apart from other components of the actuation device so as to avoid interference. In an embodiment, the security barrier further includes a connection member, spaced apart from the one or more pivotable member, connecting the barrier member to the support. An advantage is to provide a member affording stability while the barrier member is in motion (as well as other effects). In addition, as distinct from a system involving a screw jack, this embodiment affords the possibility for the connection member to lock the security barrier in a deployed state. In each case, the actuation device is separate from the connection member (and locking action), thus enabling independent repair or replacement of each. Preferably, the connection member provides a lock mechanism to lock the security barrier in the deployed position. Preferably, the lock mechanism is an over-centre arrangement of the connection member. An advantage is to provide a stable and independent means to lock the security barrier in a deployed state. Such an arrangement may provide the advantage of improving the ability of the security barrier to inhibit passage of a vehicle. In an embodiment, the connection member comprises at least one connection rod coupled at one part thereof to one of the barrier member and the support via a third rotational coupling, whereby the connection rod is pivotable, during said pivoting of the barrier member, relative to the barrier member or the support. An advantage is to provide a member affording stability while the barrier member is in motion, as well as to afford the possibility for the connection member to lock the security barrier in a deployed state. In an embodiment, the connection member comprises at least a first rod and a second rod, wherein the first rod is coupled at a first end thereof to the barrier member via a third rotational coupling and the second rod is coupled at a first end thereof to the support via a fourth rotational coupling, and wherein the first rod is coupled at a second end thereof to a second end of the second rod via a fifth rotational coupling. An advantage is to provide a member affording stability while the barrier member is in motion, as well as to afford the possibility for the connection member to lock the security barrier in a deployed state. Preferably, in use, during the pivoting movement of the barrier member between the stowed position and the deployed position, in response to the fifth rotational coupling passing a centre line joining the third rotational coupling and the fourth rotational coupling, the connection member enters into a locked state. An advantage is to enable the connection member to lock the security barrier in a deployed state by controlling the pivoting movement applied to the barrier member. Such an arrangement provides a convenient way to move the security barrier between the stowed and the deployed positions and to lock the security barrier in the deployed position. Preferably, in use, the connection member toggles between the locked state and a movable state, in which rotation of the connection member is possible, in response to successive further pivoting movements of the barrier member in the same sense as the movement towards the deployed position. An advantage is to enable locking and freeing of the security barrier simply by controlling the pivoting movement applied to the barrier member. In an embodiment, the barrier member is substantially wedge-shaped, and the barrier pivot axis is at an apex of the wedge. Preferably, the barrier member is substantially the shape of a quadrant of a right circular cylinder. Such a security barrier provides the advantage that the barrier member can be rapidly deployed merely via rotary action. Preferably, the barrier member is formed of a plurality of wedge-shaped sections having respective radial parts and circumferential parts. Such a security barrier provides the advantage that the barrier member can be located shallowly in the ground in the stowed position. The security barrier can be more easily installed in the ground because relatively shallow foundations can be used which are less likely to interfere with services such as power lines, drains, or communication cables. Preferably, from the lowermost wedge-shaped section to the uppermost wedge-shaped section the radial parts and circumferential parts are successively larger, whereby in the stowed position, the wedge-shaped sections are nested so as to stow with a thickness equal to that of the uppermost wedge-shaped section. An advantage is that the barrier member can be located shallowly in the ground in the stowed position and can be more easily installed in the ground because relatively shallow foundations can be used. In an embodiment, the barrier member comprises an upper surface for positioning substantially at ground level in the stowed position. This affords rapid deployment of an effective barrier. According to another aspect of the invention, there provided a drive device for lifting and / or rotating a barrier member of a security barrier, the drive device comprising: a transmission having an input component, configured to receive motion from an electromachinery device, and an output shaft, configured to output rotational motion; and a rotational drive member, fixedly attached for rotation on the output shaft; wherein the transmission includes one or more gears configured such that, in response to motion received at the input component, for conversion into movement of the barrier member, the output shaft of the transmission and said rotational drive member are operable to rotate by a predetermined total angle. An advantage is to provide a device that can be installed in a security barrier as an independent component, swapped in and out, and that is capable of rapid and efficient deployment of a barrier member of the security barrier. In an embodiment, the rotational drive member includes an actuation member for operating the barrier member. Preferably, the actuation member is an elongate member for coupling at a distal end thereof to the barrier member by a first rotational coupling defining a first axis of rotation, whereby the actuation member is rotatable about the first axis of rotation. An advantage is to facilitate rapid deployment the barrier member via rotary action. Furthermore, a mechanical advantage may be proved. In an embodiment, the actuation member is arranged to be rotatable. Preferably, the rotational drive member operable to engage the actuation member for movement thereof. An advantage is to facilitate rapid deployment the barrier member via rotary action. Preferably, the drive shaft defines a second axis of rotation, the actuation member is an elongate member coupled at a proximal end thereof to the rotational drive member by a second rotational coupling defining a third axis of rotation, whereby the actuation member is rotatable relative to the rotational drive member about the third axis of rotation. An advantage is that the actuation member can act upon a distal point on the pivotable barrier member, thereby facilitating rapid deployment the barrier member via rotary action. Preferably, the third axis of rotation is spaced apart on the rotational drive member from the second axis of rotation, whereby the rotational drive member is operable for rotating and / or lifting the actuation member in response to rotation of the rotational drive member. An advantage is that the rotational drive member simultaneously causes both lifting and rotation of the, thereby facilitating rapid pivoting of the barrier member and thus its deployment. Preferably, the first axis of rotation, the second axis of rotation and / or the third axis of rotation are parallel. As distinct from a system involving a screwjack, this embodiment provides an efficient arrangement by which rotary motion is transferred to the pivotable barrier member, facilitating rapid deployment the barrier member via rotary action. The predetermined total angle may (i) be less than 300 degrees, (ii) be less than 270 degrees, or (ii) be 260 degrees. Thus, an advantage is that a smaller angular rotation is required than that needed (e.g. 360 degrees) in comparable systems. As compared with systems using a screwjack (which are difficult to operate quickly), the drive device of this embodiment may require only 1.5 seconds to reach full height (deployed position). In an embodiment, the rotational drive member has a first bearing surface and a casing of the transmission or stop member fixedly attached thereto has a second bearing surface, said bearing surfaces arranged to abut each other when rotation through said predetermined total angle is complete, corresponding to the barrier member being in the deployed position. An advantage is to limit the amount of rotary motion during deployment, facilitating relatively high-speed rotation and ensuring that other components are not unduly stressed at the end of travel. Such an arrangement has the advantage of inhibiting the barrier member from being forced from the support in the event of a crash impact by a vehicle. Such an arrangement also provides a stop so that the barrier member is fully deployed in a particular position. Preferably, the rotational drive member includes a radially extending projection, and the first bearing surface comprises a non-circumferential surface of the projection. An advantage is that the rotational drive member can be simply manufactured with a robust part for blocking further rotation upon abutment. In an embodiment, said predetermined total angle extends between a start point of the rotation of the rotational drive member and the point at which said bearing surfaces abut each other. An advantage is to reduce or minimise the angular movement required. Preferably, the rotational drive member is a plate-shaped member. An advantage is that the members are relatively lightweight components (facilitating rapid movement), and can be spaced apart from other components of the actuation device so as to avoid interference. In an embodiment, the input component is configured to receive rotational motion about one axis, and the output shaft is configured to output rotational motion about another axis, perpendicular to the one axis. This enables a shaft of a motor to be mounted for driving the input component about the first axis; the size of the interface between the motor and transmission can be minimised and, with regard to prevention of ingress of dirt or debris, only sealing around that interface or motor shaft are required. Preferably, said another axis is parallel to a barrier pivot axis about which the barrier member is rotatable and / or the rotational drive member rotates, in use, in a plane perpendicular to the barrier pivot axis. An advantage is that the barrier member is not moved by vertical pushing or lifting, but by rotary movement of members rotating about an axis, facilitating rapid movement to the deployed position. Preferably, the input component is a socket configured to receive and be driven by the output shaft of an electric motor. This enables a shaft of a motor to be mounted for driving the input component about the first axis; the size of the interface between the motor and transmission can be minimised and, with regard to prevention of ingress of dirt or debris, only sealing around that interface or motor shaft are required. In an embodiment, the security barrier further includes an auxiliary drive unit comprising an auxiliary housing forming part of or attachable to the support. This enables the actuation device to be driven to cause the pivoting of the barrier member even in a case where the main drive device (e.g. including motor) is non-operational. In an embodiment, the auxiliary drive unit comprises an auxiliary drive device configured to be driven via an auxiliary input coupling element, wherein the auxiliary drive device and the housing have cooperating elements whereby, in use, the auxiliary drive device is movable between a disengaged position, in which the auxiliary drive device is disengaged from the main drive device and an engaged position, in which an output coupling element of the auxiliary drive device engages for rotation an input coupling element of the main drive device. An advantage is to enable the auxiliary drive device to be readily deployed and moved out of deployment. In an embodiment, the auxiliary drive unit comprises a translation mechanism including a manually operable handle and configured to translate the auxiliary drive device between a disengaged position, in which the auxiliary drive device is disengaged from the main drive device and an engaged position, in which an output coupling element of the auxiliary drive device engages for rotation an input coupling element of the main drive device. An advantage is to enable the auxiliary drive device to be readily deployed and moved out of deployment. Preferably, the cooperating elements comprise a planar flange on each of opposing sides of the auxiliary drive device, each flange being slidable within a slot in a respective side of the housing. An advantage is to enable controlled translational movement of the auxiliary drive device into / out of deployment. In an embodiment, the translation mechanism further includes a lever arm, the handle being attached at or near one end of the lever arm, the other end thereof being rotatable about an auxiliary axle within or on the auxiliary housing; and wherein a connecting rod configured for translational motion is connected at one end thereof to a rotational coupling on the lever arm that is spaced apart from the auxiliary axle, the connecting rod being connected at the other end thereof to the auxiliary drive unit. An advantage is to enable controlled translational movement of the auxiliary drive device into / out of deployment. In an embodiment, the translation mechanism further includes a spring biassing element attached at one end thereof to the auxiliary housing and attached at the other end thereof to a point on the lever arm, wherein the spring biassing element is configured to bias the auxiliary drive device (i) into the disengaged position while the auxiliary drive device is between the disengaged position and a predetermined intermediate point in the travel between the disengaged position and the engaged position, and / or (ii) into the engaged position while the auxiliary drive device is at the predetermined intermediate point or between the predetermined intermediate point and the engaged position. An advantage is to afford effective toggling of the auxiliary drive device into / out of its deployment position. According to another aspect, there is provided an auxiliary drive unit for a security barrier having a main drive device, the auxiliary drive unit comprising an auxiliary housing forming part of or attachable to the security barrier, wherein the auxiliary drive unit comprises an auxiliary drive device configured to be driven via an auxiliary input coupling element, wherein the auxiliary drive device and the housing have cooperating elements such that the auxiliary drive device is movable between a disengaged position in which the auxiliary drive device is disengaged from the main drive device, and an engaged position in which an output coupling element of the auxiliary drive device is engageable with an input coupling element of the main drive device for rotation thereof. Such an auxiliary drive unit enables the security barrier to be operated even in a case where the main drive device (e.g. including motor) is non-operational. In an embodiment, the auxiliary drive unit comprised a translation mechanism including a manually operable handle and configured to translate the auxiliary drive device between the disengaged position and the engaged position. Preferably, the cooperating elements comprise a planar flange on each of opposing sides of the auxiliary drive device, each flange being slidable within a slot in a respective side of the housing. An advantage is to enable controlled translational movement of the auxiliary’ drive device into / out of deployment. In an embodiment, the translation mechanism further includes a lever arm, the handle being attached at or near one end of the lever arm, the other end thereof being rotatable about an auxiliary axle within or on the auxiliary housing; and wherein a connecting rod configured for translational motion is connected at one end thereof to a rotational coupling on the lever arm that is spaced apart from the auxiliary axle, the connecting rod being connected at the other end thereof to the auxiliary drive unit. An advantage is to enable controlled translational movement of the auxiliary drive device into / out of deployment. In an embodiment, the translation mechanism further includes a spring biassing element attached at one end thereof to the auxiliary housing and attached at the other end thereof to a point on the lever arm, wherein the spring biassing element is configured to bias the auxiliary drive device (i) into the disengaged position while the auxiliary drive device is between the disengaged position and a predetermined intermediate point in the travel between the disengaged position and the engaged position, and / or (ii) into the engaged position while the auxiliary drive device is at the predetermined intermediate point or between the predetermined intermediate point and the engaged position. An advantage is to afford effective toggling of the auxiliary drive device into / out of its deployment position. According to another aspect, there is provided a method of operating a security barrier comprising a support and a barrier member which is pivotable, in use, relative to the support about a barrier pivot axis, the support having an upper part for positioning substantially at ground level, the barrier pivot axis being substantially at the upper part, the method including: operating a main drive device so as to move the barrier member between a stowed position, in which the barrier member is disposed within the support and / or coplanar with the ground, and a deployed position by pivoting the barrier member relative to the support; and wherein pivoting the barrier member relative to the support includes providing said pivotable movement via an actuation device having at least one pivotable member pivotable about a respective axis of rotation parallel to the barrier pivot axis. In one embodiment the method further includes an actuation member which is an elongate member coupled at a distal end thereof to the barrier member by a first rotational coupling defining a first axis of rotation, the method including rotating the actuation member about the first axis of rotation to move the barrier member. An advantage is that the actuation member can act upon a distal point on the pivotable barrier member, thereby facilitating rapid deployment the barrier member via rotary action. Preferably, the method further includes operating the rotational drive member to engage the actuation member for movement thereof. An advantage is that the rotational drive member simultaneously causes both lifting and rotation of the, thereby facilitating rapid pivoting of the barrier member and thus its deployment. In an embodiment, said moving of the barrier member comprises, while the barrier member is in the stowed position, commencing pivoting the barrier member relative to the support and pivoting the barrier member to an intermediate angle of travel. Preferably, the said moving of the barrier member comprises continuing to pivot the barrier member relative to the support so as to pivot the barrier member to a predetermined total angle of travel, greater than the intermediate angle, and ceasing to pivot the barrier member. In an embodiment, the actuation device comprises a lock mechanism, the method including locking the security barrier in the deployed position using the lock mechanism. Preferably, locking the security barrier in the deployed position comprises locking the security barrier at the intermediate angle of travel of the barrier member. In an embodiment, the lock mechanism comprises an over-centre arrangement of the actuation member and a connection member, the method including locking the security barrier in the deployed position using the over-centre arrangement. Preferably, the intermediate angle of travel corresponds to an overcentre point of the over-centre arrangement, and locking the security barrier in the deployed position comprises locking the security barrier at the intermediate angle of travel of the barrier member after pivoting the barrier member through the predetermined total angle of travel. In an embodiment, the method further includes, while the barrier member is in the stowed position, repeating the pivoting of the barrier member in the same sense beyond the intermediate angle of travel so as to release the lock mechanism, and thereby cause the movement of the barrier member between the deployed position and the stowed position. Through the aforementioned methods, analogous advantages are provided as in relation to the aforementioned security barrier and main drive device. According to an alternative characterisation of the invention there is provided a security barrier comprising a support and a barrier member which is pivotable relative to the support between a stowed position and a deployed position about a horizontal barrier pivot axis, the support having an upper part for positioning substantially at ground level, the barrier pivot axis being substantially at the upper part, wherein a main drive device is operable to provide said pivotable movement of the barrier member relative to the support via an actuation device having an actuation member and a rotational drive member, the rotational drive member being pivotable about an axis of rotation parallel to the barrier pivot axis, the actuation member being an elongate member coupled at a distal end thereof to the barrier member by a first rotational coupling, the actuation member being coupled at a proximal end thereof to the rotational drive member by a second rotational coupling which is spaced apart the axis of rotation of the rotational drive member. According to another alternative characterisation of the invention there is provided a main drive device for lifting and / or rotating a barrier member of a security barrier, the main drive device comprising: a transmission having an input component, configured to receive motion from an electromachinery device, and an output shaft, configured to output rotational motion; and a rotational drive member, fixedly attached for rotation on the output shaft; wherein the transmission includes one or more gears configured such that, in response to motion received at the input component, for conversion into movement of the barrier member, the output shaft of the transmission and said rotational drive member are operable to rotate by a predetermined total angle, the rotational drive member being pivotable about an axis of rotation, the actuation member being an elongate member for coupling at a distal end thereof to the barrier member by a first rotational coupling, the actuation member being coupled at a proximal end thereof to the rotational drive member by a second rotational coupling which is spaced apart the axis of rotation of the rotational drive member. According to another alternative characterisation of the invention there is provided a method of operating a security barrier apparatus according to the alternative characterisations of the invention. Any preferred or optional features of one aspect of the invention may be preferred or optional feature of other aspects of the invention. Brief Description of the Drawings Other features of the invention will be apparent from the following description of preferred embodiments shown by way of example only with reference to the accompanying drawings, in which; Figure 1 shows a perspective view of a security barrier in a fully deployed position according to an embodiment of the invention; Figure 2 shows a perspective view of the security barrier shown in Figure 1; Figure 3 shows a side view of the security barrier of Figures 1 and 2 in a stowed position; Figure 4 shows a side view of the security barrier of Figures 1 and 2 in a partially deployed position; Figure 5 shows a side view of the security barrier of Figures 1 and 2 in a fully deployed position; Figure 6 shows a perspective view of a drive arrangement shown in Figures 3 to 5; Figure 7 shows a plan view of a manual drive arrangement shown in Figures 3 to 5; Figure 8 shows a perspective view of the manual drive arrangement shown in Figure 7; and Figure 9 shows a diagram of a method according to an embodiment of the invention. Detailed Description Figure 1 shows a perspective view of a security barrier in a fully deployed position according to an embodiment of the invention, generally designated 10. Figure 2 shows a perspective view of the security barrier shown in Figure 1. In Figures 1 and 2 like features are shown with like reference numerals. In Figures 1 and 2 the security barrier 10 is shown to comprise a barrier member 12 and a support 14. The barrier member 12 is preferably wedge shaped in the deployed position and comprises four wedge portions 16,18, 20, 22, which nest within each other in the stowed position and are substantially of equal size. Each wedge portion 16, 18, 20, 22 is pivotably attached to the support 14 about a pivot axis 15 (also referred to herein as the “barrier pivot axis”) substantially at a ground level 31 (see Figure 3). It will be understood that the ground level 31 is, for example, level with a road and in the illustrated embodiment the four wedge portions 16, 18, 20, 22 are arranged to be pivoted relative to the support 14 so that they partially rotate. In the deployed position (Figs 1 and 2) the barrier member 10 is substantially the shape of a sector of a right circular cylinder with a sector angle of about 45 degrees, and such that the pivot axis 15 is the axis of the cylinder. In the deployed position the wedge shape has a curved surface 25 (i.e., outer, circumferential surface) which is an impact surface, so that in the event of an impact from a vehicle in the direction indicated by arrow 24 the security barrier 10 is inhibited from collapsing or moving towards the stowed position. In an embodiment, the wedge shape has an upper flat surface 26 on which vehicles can drive when the security barrier 10 is in the stowed position (Fig. 3). The support 14 is substantially the shape of a rectangular box and is cast into the ground with concrete foundations (not shown) and using rebar 28 according to known arrangements. Also shown is a drive housing 30, which contains the drive device (see Figures 3 to 8) and may be part of the support 14. Alternatively, the drive housing 30 is an auxiliary housing that may be removably securely attached to the remainder of the support 14, e.g. by bolting. The barrier member 12, the support 14, and the drive housing 30 may be constructed of steel plate which is welded together to form the required shapes. In the illustrated embodiment, the four wedge portions 16, 18, 20, 22 are deployed from the support 14 through an aperture 32 (see especially Fig. 1) of the support 14. The four wedge portions 16, 18, 20, 22 are preferably close fitting with the aperture 32 such that there is a gap of approximately 5 - 10mm between the barrier member 12 and the aperture 32. Such an arrangement may inhibit debris from entering the aperture 32, and may also assist with improving the safety of operation for the security barrier 10. In an embodiment, the plurality of wedge-shaped portions 16, 18, 20, 22 having respective radial parts and circumferential parts. In an embodiment, from the lowermost wedge-shaped portion 22 to the uppermost wedge-shaped portion 16 the radial parts and circumferential parts are successively larger, whereby (i) in the stowed position, the wedge-shaped portions are nested so as to stow with a depth (i.e. thickness) equal to that of the uppermost wedge-shaped portion. The barrier member 12 described above is shown to be a quadrant of a right circular cylinder, but it will be appreciated that any suitable shaped barrier member 12 may be used. In one embodiment the barrier member 12 is a curved plate. As the security barrier 12 moves from the stowed position (Fig. 3) to the deployed position (Figs 1, 2 and 5) the barrier member 12 initially pivots about the pivot axis 15 as shown by arrow 42 in Figs 3 to 5. Movement of the barrier member 12 and the support 14 between the stowed and the deployed positions is achieved by using an actuation device or mechanism 33 driven by a main drive device 34, e.g. an electric motor, which may be alternatively termed a drive device. The actuation device or mechanism 33 has at least one pivotable member pivotable about a respective axis of rotation parallel to the barrier pivot axis 15, as described further below. More particularly, in an embodiment, the actuation device 33 includes an actuation member 40 operable to engage the barrier member 12 for movement of the latter. The actuation member 40 may be an elongate member coupled at a distal end thereof to the barrier member 12 by a first rotational coupling 44 defining a first axis of rotation, whereby the actuation member 40 is rotatable relative to the barrier member about the first axis of rotation (preferably parallel to the barrier pivot axis 15). In an embodiment, the actuation member 40 is a plate-shaped member, and / or lies, in use, in a plane perpendicular to the barrier pivot axis 15. The actuation member 40 may arranged to be rotatable relative to the support 14. More particularly, in an embodiment, the actuation device 33 includes a rotational drive member 38 operable to engage the actuation member 40 for movement of the latter. The rotational drive member 38 may be fixedly mounted for rotation on a drive shaft 50 for providing the pivotable movement, the drive shaft 50 defining a second axis of rotation (preferably parallel to the barrier pivot axis 15). In an embodiment, the rotational drive member 38 is a plate-shaped member, and / or lies, in use, in a plane perpendicular to the barrier pivot axis 15. In an embodiment, a proximal end of the elongate actuation member 40 is coupled to the rotational drive member 38 by a second rotational coupling 43 defining a third axis of rotation, whereby the actuation member 40 is rotatable relative to the rotational drive member 38 about the third axis of rotation (preferably parallel to the barrier pivot axis 15). As seen in Figs 4 and 5, in this embodiment, the third axis of rotation (i.e. second rotational coupling 43) is spaced apart on the rotational drive member 38 from the second axis of rotation (i.e. drive shaft 50), whereby the rotational drive member 38 is operable, in use, for rotating and / or lifting the actuation member 40 in response to rotation of the rotational drive member 38 by the shaft 50. It will also be appreciated that a mechanical advantage is provided by the rotational drive member 38 and the actuation member 40, in part due to the second rotational coupling 43 that is offset from the second axis of rotation 50, and the manner in which barrier member 12 is operated via the first rotational coupling 44. In an embodiment, the actuation device 33 includes a transmission operable to receive driving motion from the main drive device 34 and to transmit rotational motion to the at least one pivotable member, e.g. rotational drive member 38. As seen in Fig. 5, the actuation device 33 may be secured to (the base of) the support 14 by means of fixing strut 59, which is secured at each end by bolts. In Figs 3 to 5, the drive shaft 50 is the output shaft of the transmission. In an embodiment, the transmission includes one or more gears (not shown) configured such that, in response to motion received at an input component (e.g. an input socket or shaft engaged by motor 34) of the transmission, for conversion into said pivotable movement of the barrier member 12, the output shaft 50 of the transmission and / or said rotational drive member 38 rotates, in use, by a total angle that (i) is less than 300 degrees, (ii) is less than 270 degrees, (ii) is 260 degrees. In use, the total angle extends between a start point (Fig. 3) of pivoting motion and the point (Fig. 5 and 6) at which said bearing surfaces (46, 48) abut each other. In an embodiment, the rotational drive member 38 has a first bearing surface (item 46 in Fig 5) and the support 14 has a second bearing surface (48 in Fig 5), said bearing surfaces arranged to abut each other when the barrier member is in the deployed position. Such an arrangement inhibits the barrier member 12 from pivoting fully out of the support 14 when moved to the deployed position (Fig. 5). As best seen in Fig. 6, the rotational drive member 38 includes a radially extending projection 39, and the first bearing surface 46 comprises a non-circumferential surface of the projection 39. The first bearing surface 46 as shown is a radial surface of the projection 39 As noted above, the security barrier member 10 has bearing surfaces 46, 48 arranged to abut each other when the barrier member 12 is in the deployed position. At least one of the bearing surfaces comprises at least one plate (labelled 49 in Fig. 3) attached to the support 14. Such an arrangement stops the barrier member 12 from pivoting fully out of the support 14 when moved to the deployed position, and also assists in locking the barrier member 12 in the deployed position. In an embodiment, once the barrier member 12 is in the deployed position a locking device, such as a pin, may be used to secure it in position relative to the support 14. In an embodiment, the security barrier 10 further includes a connection member (generally designated 23 in Fig. 5), spaced apart from the one or more pivotable members (38, 40) of the actuation device 33, connecting the barrier member 12 to the support 14. Suitably, the connection member 23 provides a lock mechanism to lock the security barrier 10 in the deployed position. Preferably, the lock mechanism is an over-centre arrangement of the connection member 23. For example, in Figure 5 the middle pin of the connecting rod 23 is shown to have moved slightly past the dashed line 52 position prior to the bearing surfaces 46, 48 abutting, which provides an over-centre lock arrangement for the security barrier 10. In an embodiment, the connection member 23 comprises at least one connection rod 54, 56 coupled at one part thereof to one of the barrier member 12 and the support 14 via a further rotational coupling, whereby the connection rod 54, 56 is rotatable, during said pivoting of the barrier member 12, relative to the barrier member 12 or the support 14. In an embodiment, the connection member 23 comprises at least a first rod 54 and a second rod 56, wherein the first 54 rod is coupled at a first end thereof to the barrier member 12 via a third rotational coupling (not shown in Fig. 5) and the second rod 56 is coupled at a first end thereof to the support via a fourth rotational coupling 57, and wherein the first rod is coupled at a second end thereof to a second end of the second rod via a fifth rotational coupling 58. Preferably, through the provision of the over-centre lock arrangement, during the pivoting movement of the barrier member 12 between the stowed position (Fig. 3) and the deployed position (Fig. 5), in response to the fifth rotational coupling 58 passing a centre line 52 joining the third rotational coupling and the fourth rotational coupling 57, the connection member 23 enters into a locked state. It will be appreciated that the over-centre lock arrangement requires the barrier member 12 to move slightly downwards after it has reached a maximum height (e.g. from a final angle of pivoting to an intermediate angle of pivoting that was previously passed during movement). Such an over-centre lock arrangement means that in the event of an impact from a vehicle in the direction indicated by arrow 24 the security barrier 10 is inhibited from collapsing or moving towards the stowed position. It will be appreciated that through the use of the over-centre lock arrangement, in use, the connection member 23 toggles between the locked state and a movable state, in which rotation of the connection member 23 is possible, in response to successive further pivoting movements of the barrier member 12 in the same sense as the movement towards the deployed position. Furthermore, the over-centre lock arrangement inhibits collapse of the security barrier 10 in the event of an impact in the direction of arrow 24. The over-centre lock arrangement also inhibits collapse of the security barrier 10 in the event of a failure of the drive mechanism, for example due to loss of power to the drive mechanism. In an alternative embodiment the security barrier 10 does not have an over-centre arrangement and the connecting rod 23 is substantially vertical when the security barrier 10 is in the deployed position. Figures 7 and 8 show plan and perspective views of an auxiliary drive unit 36 shown in Figures 3 to 5. The auxiliary drive unit 36 may comprise an auxiliary housing 72 forming part of or attachable to the support 14. The auxiliary drive unit 36 may comprises an auxiliary drive device 74 configured to be driven via an auxiliary input coupling element 82 (e.g. hex socket). Preferably, the auxiliary drive device 74 and the auxiliary housing 72 have cooperating elements whereby, in use, the auxiliary drive device 74 is movable (indicated by arrow A) between a disengaged position, in which the auxiliary drive device 74 is disengaged from the main drive device 34 (e.g. a motor in Fig. 6) and an engaged position, in which an output coupling element (e.g. output shaft 84) of the auxiliary drive device 74 engages for rotating an input coupling element (e.g. socket of a shaft) of the main drive device 34. In an embodiment, the auxiliary drive unit 36 comprises a translation mechanism including a manually operable handle 80 and configured to translate the auxiliary drive device 74 between a disengaged position, in which the auxiliary drive device is disengaged from the main drive device 34 and an engaged position, in which an output coupling element (e.g. output shaft 84) of the auxiliary drive device 74 engages for rotation an input coupling element (e.g. socket of a shaft) of the main drive device 34. As seen in Figs 7 and 8, in an embodiment, the cooperating elements comprise a planar flange 78 on each of opposing sides of the auxiliary drive device 74, each flange 78 being slidable within a slot 79 (Fig. 8) in a respective side of the housing 72. In an embodiment, the translation mechanism further includes a lever arm 76, the handle 80 being attached at or near one end of the lever arm 76, the other end being rotatable about an auxiliary axle 77 within or on the auxiliary housing 72. Preferably, a connecting rod 75 configured for translational motion is connected at one of its ends to a rotational coupling 71 on the lever arm 76 that is spaced apart from the auxiliary axle 77, the connecting rod 75 being connected at its other end to the auxiliary drive unit 74. In an embodiment, the translation mechanism further includes a spring biassing element (e.g. spring 73) attached at one of its ends to the auxiliary housing 72 and attached at its other end to a point on the lever arm 76. Preferably, the spring biassing element is configured to bias the auxiliary drive device 74 (i) into the disengaged position while the auxiliary drive device 74 is between the disengaged position and a predetermined intermediate point in the travel between the disengaged position and the engaged position, and / or (ii) into the engaged position while the auxiliary drive device 74 is at the predetermined intermediate point or between the predetermined intermediate point and the engaged position. In Figures 7 and 8 the handle 80 is shown which has a sliding motion to engage / disengage a gear (not shown) on an end the motor shaft (of the main drive device 34). The nut 82 can then be turned (e.g. by applying an electric drill) to drive a small gearbox (not shown) within the auxiliary drive unit 36 to drive the output shaft 84 and to move barrier member 12 between the stowed and the deployed position. Figure 9 shows a diagram of a method according to an embodiment of the invention, generally designated 90. The method 90 comprises operating the main drive device so as to move the barrier member between a stowed position, in which the barrier member is disposed within the support and / or coplanar with the ground, and a deployed position by pivoting the barrier member relative to the support. Pivoting the barrier member relative to the support includes providing said pivotable movement via an actuation device having at least one pivotable member pivotable about a respective axis of rotation parallel to the barrier pivot axis. More particularly, the method 90 may comprise, while the barrier member is in the stowed position, commencing (92) pivoting the barrier member relative to the support and continuing pivoting (94) the barrier member to an intermediate angle of travel. Then, the method 90 may comprise, continuing (96) to pivot the barrier member relative to the support so as to pivot the barrier member to a predetermined total angle of travel, greater than the intermediate angle, and ceasing to pivot the barrier member. In an embodiment, in a case where the actuation device comprises a lock mechanism, the method includes locking (97) the security barrier in the deployed position using the lock mechanism. Locking the security barrier in the deployed position may comprise locking the security barrier at the intermediate angle of travel of the barrier member 12. In a case where the lock mechanism comprises an over-centre arrangement of the actuation member and the connection member, the method may including locking the security barrier in the deployed position using the over-centre arrangement. In an embodiment, the intermediate angle of travel corresponds to an overcentre point of the over-centre arrangement, and locking the security barrier in the deployed position comprises locking the security barrier at the intermediate angle of travel of the barrier member after pivoting the barrier member through the predetermined total angle of travel. As a means of toggling the security barrier 10 out of the deployed position, the method may further comprise, while the barrier member is in the stowed position, repeating (98) the pivoting of the barrier member in the same sense beyond the intermediate angle of travel so as to release the lock mechanism, and thereby cause the movement of the barrier member between the deployed position and the stowed position. The method may further comprise operating the actuation device 33 to cause barrier member 12 to return to the stowed position. The method further includes an actuation member which is an elongate member coupled at a distal end thereof to the barrier member by a first rotational coupling defining a first axis of rotation, the method including rotating the actuation member about the first axis of rotation to move the barrier member. The method further includes operating the rotational drive member to engage the actuation member for movement thereof. The security barrier 10 described above is substantially the width of a road, for example between 4 - 6m in width. It is also envisaged that the security barrier 10 might be narrower than this to inhibit access of a vehicle to a passageway or driveway. With such an arrangement a less powerful drive mechanism may be used to move the barrier member 12. In the embodiments of Figures 1 - 9 the security barrier 10 described is intended to be crash proof so that a car or lorry travelling at speed is substantially prevented from passing. As such the security barrier 10 is relatively large and constructed of relatively heavyweight material. Such a security barrier 10 might alternatively be termed a high security barrier, a vehicle barricade, a truck stopper or a road blocker and might be particularly useful to guard against terrorist activities. It is also envisaged that a smaller version of the above described embodiments could be used for application at the home or business premises. Such a less heavy duty security barrier 10 may not require a drive mechanism and may be operated by hand. The less heavy duty security barrier 10 may be used to guard a parking space or driveway and may be constructed of lighter materials. The high security barrier 10 and the smaller version security barrier 10 may alternatively be termed a vehicle security barrier. With the above described embodiments, it will also be appreciated that the barrier member 12 is movable relative to the body 16 between a stowed position where the barrier member 12 is at or below an upper part of the support 14, and a deployed position where at least a part of the barrier member 12 is above the upper part of the support 14. The upper part may be at the pivot point, i.e. the pivot axis 18, which is at the ground level 20.

Claims

1. A security barrier comprising a support and a barrier member which is pivotable relative to the support between a stowed position and a deployed position about a horizontal barrier pivot axis, the support having an upper part for positioning substantially at ground level, the barrier pivot axis being substantially at the upper part, wherein a main drive device is operable to provide said pivotable movement of the barrier member relative to the support via an actuation device having at least one pivotable member which is pivotable about a respective axis of rotation parallel to the barrier pivot axis.

2. A security barrier according to claim 1, wherein the at least one pivotable member includes an actuation member operable to engage the barrier member for movement thereof.

3. A security barrier according to claim 2, wherein the actuation member is an elongate member coupled at a distal end thereof to the barrier member by a first rotational coupling defining a first axis of rotation, whereby the actuation member is rotatable relative to the barrier member about the first axis of rotation.

4. A security barrier according to any of claims 2 to 3, wherein the actuation member is arranged to be rotatable relative to the support.

5. A security barrier according to any of claims 2 to 4, wherein the at least one pivotable member includes a rotational drive member operable to engage the actuation member for movement thereof6. A security barrier according to claim 5, wherein the rotational drive member is fixedly mounted for rotation on a drive shaft for providing said pivotable movement, the drive shaft defining a second axis of rotation.

7. A security barrier according to claim 5 or 6, when dependent upon claim 2, wherein the actuation member is an elongate member coupled at a proximal end thereof to the rotational drive member by a second rotational coupling defining a third axis of rotation, whereby the actuation member is rotatable relative to the rotational drive member about the third axis of rotation.

8. A security barrier according to claim 7, wherein the third axis of rotation is spaced apart on the rotational drive member from the second axis of rotation, whereby the rotational drive member is operable for rotating and / or lifting the actuation member in response to rotation of the rotational drive member.

9. A security barrier according to any of claims 3 to 8, wherein the first axis ofrotation, the second axis of rotation and / or the third axis of rotation is parallel to the barrier pivot axis.

10. A security barrier according to any preceding claim, wherein the actuation device includes a transmission operable to receive driving motion from the main drive device and to transmit rotational motion to at least one pivotable member.

11. A security barrier according to claim 10, when dependent upon claim 6, wherein the drive shaft is the output shaft of the transmission.

12. A security barrier according to any of the preceding claims, wherein one or more of the pivotable members has a first bearing surface and the support has a second bearing surface, said bearing surfaces arranged to abut each other when the barrier member is in the deployed position.

13. A security barrier according to claim 12, when dependent upon claim 5, wherein the first bearing surface is disposed on the rotational drive member.

14. A security barrier according to claim 13, wherein the rotational drive member includes a radially extending projection, and the first bearing surface comprises a non-circumferential surface of the projection.

15. A security barrier according to claim 10, or any claim dependent thereon, wherein the transmission includes one or more gears configured such that, in response to motion received at an input component of the transmission, for conversion into said pivotable movement of the barrier member, the output shaft of the transmission and / or saidrotational drive member rotates, in use, by a total angle that (i) is less than 300 degrees, (ii) is less than 270 degrees, (ii) is 260 degrees.

16. A security barrier according to claim 15, when dependent upon any of claims 12 to 14, wherein said total angle extends between a start point of pivoting motion and the point at which said bearing surfaces abut each other.

17. A security barrier according to any of claims 12 to 16, wherein at least one of the bearing surfaces is disposed on at least one plate forming part of or connected to a pivotable member or the support.

18. A security barrier according to any of claims 2 to 17, wherein the actuation member and / or the rotational drive member is a plate-shaped member, and / or lies, in use, in a plane perpendicular to the barrier pivot axis.

19. A security barrier according to any of the preceding claims, further including a connection member, spaced apart from the one or more pivotable member, connecting the barrier member to the support.

20. A security barrier according to claim 19, wherein the connection member provides a lock mechanism to lock the security barrier in the deployed position.

21. A security barrier according to claim 20, wherein the lock mechanism is an overcentre arrangement of the connection member.

22. A security barrier according to any of claims 19 to 21, wherein the connection member comprises at least one connection rod coupled at one part thereof to one of the barrier member and the support via a third rotational coupling, whereby the connection rod is pivotable, during said pivoting of the barrier member, relative to the barrier member or the support.

23. A security barrier according to any of claims 19 to 21, wherein the connection member comprises at least a first rod and a second rod, wherein the first rod is coupled at a first end thereof to the barrier member via a third rotational coupling and the second rod is coupled at a first end thereof to the support via a fourth rotational coupling, and wherein the first rod is coupled at a second end thereof to a second end of the second rod via a fifth rotational coupling.

24. A security barrier according to claim 23, wherein, in use, during the pivoting movement of the barrier member between the stowed position and the deployed position, in response to the fifth rotational coupling passing a centre line joining the third rotational coupling and the fourth rotational coupling, the connection member enters into a locked state.

25. A security barrier according to claim 24, wherein, in use, the connection member toggles between the locked state and a movable state, in which rotation of the connection member is possible, in response to successive further pivoting movements of the barrier member in the same sense as the movement towards the deployed position.

26. A security barrier according to any of the preceding claims, wherein the barrier member is substantially wedge-shaped, and the barrier pivot axis is at an apex of the wedge.

27. A security barrier according to claim 26, wherein the barrier member is substantially the shape of a quadrant of a right circular cylinder.

28. A security barrier according to claim 26 or 27, wherein the barrier member is formed of a plurality of wedge-shaped sections having respective radial parts and circumferential parts.

29. A security barrier according to claim 28, wherein from the lowermost wedge-shaped section to the uppermost wedge-shaped section the radial parts and circumferential parts are successively larger, whereby (i) in the stowed position, the wedge-shaped sections are nested so as to stow with a thickness equal to that of the uppermost wedge-shaped section.

30. A security barrier according to any preceding claim, wherein the barrier member comprises an upper surface for positioning substantially at ground level in the stowed position.

31. A security barrier according to any of the preceding claims, and further including an auxiliary drive unit comprising an auxiliary housing forming part of or attachable to the support.

32. A security barrier according to claim 31, wherein the auxiliary drive unit comprises an auxiliary drive device configured to be driven via an auxiliary input coupling element, wherein the auxiliary drive device and the housing have cooperating elements whereby, in use, the auxiliary drive device is movable between a disengaged position, in which the auxiliary drive device is disengaged from the main drive device and an engaged position, in which an output coupling element of the auxiliary drive device engages for rotation an input coupling element of the main drive device.

33. A security barrier according to claim 31 or 32, wherein the auxiliary drive unit comprises a translation mechanism including a manually operable handle and configured to translate the auxiliary drive device between a disengaged position, in which the auxiliary drive device is disengaged from the main drive device and an engaged position, in which an output coupling element of the auxiliary drive device engages for rotation of an input coupling element of the main drive device.

34. A security barrier according to any of claim 32 or 33, wherein the cooperating elements comprise a planar flange on each of opposing sides of the auxiliary drive device, each flange being slidable within a slot in a respective side of the housing.

35. A security barrier according to claim 33 or 34, wherein the translation mechanism further includes a lever arm, the handle being attached at or near one end of the lever arm, the other end thereof being rotatable about an auxiliary axle within or on the auxiliary housing; and wherein a connecting rod configured for translational motion is connectedat one end thereof to a rotational coupling on the lever arm that is spaced apart from the auxiliary axle, the connecting rod being connected at the other end thereof to the auxiliary drive unit.

36. A security barrier according to claim 33, 34 or 35, wherein the translation mechanism further includes a spring biassing element attached at one end thereof to the auxiliary housing and attached at the other end thereof to a point on the lever arm, wherein the spring biassing element is configured to bias the auxiliary drive device (i) into the disengaged position while the auxiliary drive device is between the disengaged position and a predetermined intermediate point in the travel between the disengaged position and the engaged position, and / or (ii) into the engaged position while the auxiliary drive device is at the predetermined intermediate point or between the predetermined intermediate point and the engaged position.

37. A main drive device for lifting and / or rotating a barrier member of a security barrier, the main drive device comprising:a transmission having an input component, configured to receive motion from an electromachinery device, and an output shaft, configured to output rotational motion; anda rotational drive member, fixedly attached for rotation on the output shaft;wherein the transmission includes one or more gears configured such that, in response to motion received at the input component, for conversion into movement of the barrier member, the output shaft of the transmission and said rotational drive member are operable to rotate by a predetermined total angle.

38. A main drive device according to claim 37, wherein the rotational drive member includes an actuation member for operating the barrier member.

39. A main drive device according to claim 38, wherein the actuation member is an elongate member for coupling at a distal end thereof to the barrier member by a first rotational coupling defining a first axis of rotation, whereby the actuation member is rotatable about the first axis of rotation.

40. A main drive device according to any of claims 38 to 39, wherein the actuation member is arranged to be rotatable.

41. A main drive device according to any of claims 38 to 40, wherein the rotational drive member operable to engage the actuation member for movement thereof.

42. A main drive device according to claim 41, when dependent upon claim 38 and 39, wherein the drive shaft defines a second axis of rotation, the actuation member is an elongate member coupled at a proximal end thereof to the rotational drive member by a second rotational coupling defining a third axis of rotation, whereby the actuation member is rotatable relative to the rotational drive member about the third axis of rotation.

43. A main drive device according to claim 42, wherein the third axis of rotation is spaced apart on the rotational drive member from the second axis of rotation, whereby the rotational drive member is operable for rotating and / or lifting the actuation member in response to rotation of the rotational drive member.

44. A main drive device according to any of claims 39 to 43, wherein the first axis of rotation, the second axis of rotation and / or the third axis of rotation are parallel.

45. A main drive device according to any of claim 37 to 44, wherein the predetermined total angle (i) is less than 300 degrees, (ii) is less than 270 degrees, or (ii) is 260 degrees.

46. A main drive device according to any of claims 37 - 45, wherein the rotational drive member has a first bearing surface and a casing of the transmission or stop member fixedly attached thereto has a second bearing surface, said bearing surfaces arranged to abut each other when rotation through said predetermined total angle is complete, corresponding to the barrier member being in the deployed position.

47. A main drive device according to claim 46, wherein the rotational drive member includes a radially extending projection, and the first bearing surface comprises a non-circumferential surface of the projection.

48. A main drive device according to any of claims 46 to 47, wherein said predetermined total angle extends between a start point of the rotation of the rotational drive member and the point at which said bearing surfaces abut each other.

49. A main drive device according to any of claims 37 to 48, wherein the rotational drive member is a plate-shaped member.

50. A main drive device according to any of claims 37 to 49, wherein the input component is configured to receive rotational motion about one axis, and the output shaft is configured to output rotational motion about another axis, perpendicular to the one axis.

51. A main drive device according to claim 52, wherein said another axis corresponds to a barrier pivot axis about which the barrier member is rotatable and / or the rotational drive member rotates, in use, in a plane perpendicular to the barrier pivot axis.

52. A main drive device according to any of claims 37 to 51, wherein the input component is a socket configured to receive and be driven by the output shaft of an electric motor.

53. An auxiliary drive unit for a security barrier having a main drive device, the auxiliary drive unit comprising an auxiliary housing forming part of or attachable to the security barrier, wherein the auxiliary drive unit comprises an auxiliary drive device configured to be driven via an auxiliary input coupling element, wherein the auxiliary drive device and the housing have cooperating elements such that the auxiliary drive device is movable between a disengaged position in which the auxiliary drive device is disengaged from the main drive device, and an engaged position in which an output coupling element of the auxiliary drive device is engageable with an input coupling element of the main drive device for rotation thereof.

54. An auxiliary drive unit according to claim 53, comprising a translation mechanism including a manually operable handle and configured to translate the auxiliary drive device between the disengaged position and the engaged position.

55. An auxiliary drive unit according to claim 53 or 54, wherein the cooperating elements comprise a planar flange on each of opposing sides of the auxiliary drive device, each flange being slidable within a slot in a respective side of the housing.

56. An auxiliary drive unit according to claim 54 or 55, wherein the translation mechanism further includes a lever arm, the handle being attached at or near one end of the lever arm, the other end thereof being rotatable about an auxiliary axle within or on the auxiliary housing; and wherein a connecting rod configured for translational motion is connected at one end thereof to a rotational coupling on the lever arm that is spaced apart from the auxiliary axle, the connecting rod being connected at the other end thereof to the auxiliary drive unit.

57. An auxiliary drive unit according to claim 54, 55 or 56, wherein the translation mechanism further includes a spring biassing element attached at one end thereof to the auxiliary housing and attached at the other end thereof to a point on the lever arm, wherein the spring biassing element is configured to bias the auxiliary drive device (i) into the disengaged position while the auxiliary drive device is between the disengaged position and a predetermined intermediate point in the travel between the disengaged position and the engaged position, and / or (ii) into the engaged position while the auxiliary drive deviceis at the predetermined intermediate point or between the predetermined intermediate point and the engaged position.

58. A method of operating a security barrier comprising a support and a barrier member which is pivotable, in use, relative to the support about a barrier pivot axis, the support having an upper part for positioning substantially at ground level, the barrier pivot axis being substantially at the upper part, the method including:operating a main drive device so as to move the barrier member between a stowed position, in which the barrier member is disposed within the support and / or coplanar with the ground, and a deployed position by pivoting the barrier member relative to the support; andwherein pivoting the barrier member relative to the support includes providing said pivotable movement via an actuation device having at least one pivotable member pivotable about a respective axis of rotation parallel to the barrier pivot axis.

59. A method according to claim 58, and further including an actuation member which is an elongate member coupled at a distal end thereof to the barrier member by a first rotational coupling defining a first axis of rotation, the method including rotating the actuation member about the first axis of rotation to move the barrier member.

60. A method according to claim 59, and further including operating the rotational drive member to engage the actuation member for movement thereof.

61. A method according to any of claims 58 to 60, wherein said moving of the barrier member comprises, while the barrier member is in the stowed position, commencing pivoting the barrier member relative to the support and pivoting the barrier member to an intermediate angle of travel.

62. A method according to claim 61, wherein the said moving of the barrier member comprises continuing to pivot the barrier member relative to the support so as to pivot the barrier member to a predetermined total angle of travel, greater than the intermediate angle, and ceasing to pivot the barrier member.

63. A method according to any of claims 61 to 62, wherein the actuation device comprises a lock mechanism, the method including locking the security barrier in the deployed position using the lock mechanism.

64. A method according to claim 64, when dependent on claim 61 or 62, wherein locking the security barrier in the deployed position comprises locking the security barrier at the intermediate angle of travel of the barrier member.

65. A method according to claims 63 or 64, wherein the lock mechanism comprises an over-centre arrangement of the actuation member and a connection member, the method including locking the security barrier in the deployed position using the overcentre arrangement.

66. A method according to claims 65, when dependent on claim 62, wherein the intermediate angle of travel corresponds to an overcentre point of the over-centre arrangement, and locking the security barrier in the deployed position comprises locking the security barrier at the intermediate angle of travel of the barrier member after pivoting 5 the barrier member through the predetermined total angle of travel.

67. A method according to any of claims 63 to 66, when dependent upon claim 61, and further including, while the barrier member is in the stowed position, repeating the pivoting of the barrier member in the same sense beyond the intermediate angle of travel 10 so as to release the lock mechanism, and thereby cause the movement of the barrier member between the deployed position and the stowed position.

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