AU2004212597A1 - Retractable bollard - Google Patents

Description

P/00/011 Regulation 3.2

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name of Applicant: Address of Applicant: Actual Inventor: Address for Service: IMAGE BOLLARDS PTY LTD PO Box 292, Mount Lawley, Western Australia, 6929 Griffith Hack, Patent and Trade Mark Attorneys, 6th Floor, 256 Adelaide Terrace, Perth, Western Australia, 6000.

Standard Complete Specification for the invention entitled: "Retractable Bollard" Details of Associated Provisional Applications: 2003905135 and 2003905915 The following is a full description of this invention, including the best method of performing it known to me:- 2 Retractable Bollard Field of the Invention The present invention relates to a retractable bollard.

Background of the Invention Retractable bollards are characterised by a tubular housing in which resides a post that can be extended from and retracted into the housing. When the bollard is not in use the post is fully retracted within the housing.

When it is desired to deploy the bollard in order to control access to and from an area, the post is extended from the housing and locked in an extended position.

The post is typically made from steel and, necessarily in order to perform its function, is of a substantial strength and mass. As a result, reasonable physical strength is required in order to move the post to the extended position. When returning the post to the retracted position, a user may either simply unlock the post and allow it to fall by action of gravity back into its housing or alternately hold the post and lower it into the housing. If the user simply allows the post to fall by action of gravity to the retracted position then the bollard and in particular any associated locking mechanisms may become damaged. Alternately, an operator must have sufficient strength to hold the post and slowly lower it into the housing. In addition when physically lifting or lowering the post a user will often bend over, rather than squat and use their legs, which can cause back injury.

Summary of the Invention According to one aspect of the present invention there is Ros/keep/speci/complete/P54305 Retractable Bollard 21/09/04 3 provided a retractable bollard comprising: a housing; a post moveable between a retracted position where the post is substantially wholly disposed within the housing and an extended position where a length of the post is extended from the housing; and, at least one counterweight coupled to the post, wherein the at least one counterweight moves in a direction opposite to a direction of motion of the post as the post is moved between the retracted and extended positions.

According to another aspect of the present invention, there is provided a retractable bollard comprising: a housing having a main compartment and a first compartment; a post moveable between a retracted position where the post is substantially wholly disposed within the main compartment and an extended position where a length of the post is extended from the main compartment; a first counterweight disposed in the first compartment and coupled to the post, the first counterweight and the post relatively juxtaposed so that when the post moves in a direction from the retracted position to the extended position, the counterweight moves in an opposite direction and applies a force to the post that counters gravitational force acting on the post.

Preferably, the bollard comprises first and second counterweights, one of each coupled to opposite sides of the post.

Preferably, the housing comprises a main compartment in which the post is retained and first and second side compartments one on each side of the main compartment, wherein the first counterweight is located in the first Ros/keep/speci/complete/P54305 Retractable Bollard 21/09/04 4 compartment and the second counterweight is located in the second compartment.

Preferably, the bollard further comprises a first releasable lock for releasably locking the post in the extended position.

Preferably, the first releasable lock is automatically deployed when the post reaches the extended position.

Preferably, the first releasable lock comprises a first member biased toward a locked state and a first capture means provided in the housing and in a position whereby the first member engages the first capture means when the post is in the extended position to thereby lock the post in the extended position.

Preferably, the first member is supported by the post.

Preferably, the first member comprises a pin or rod and a bias mechanism for biasing the pin or rod into engagement with the first capture means.

Preferably, the first releasable lock comprises a release mechanism coupled to the first member to disengage the first member from the first capture means against the bias of the bias mechanism.

Preferably, the bollard further comprises a second releasable lock for releasably locking the post in the retracted position.

Preferably, the second releasable lock is automatically deployed when the post is in the retracted position.

Preferably, the second releasable lock comprises a second member biased toward a locked state and a second capture Ros/keep/speci/complete/P54305 Retractable Bollard 21/09/04 5 means provided in the housing at a position whereby the second member is engaged by the second capture means when the post is in the retracted position to thereby releasably lock the post in the retracted position.

According to a further aspect of the present invention, there is provided a lock for a bollard having a housing and a post adapted to be at least partially received in the housing, the lock comprising: a first member supported by the post and a bias mechanism for biasing the first member to extend from the post in a direction transverse to a longitudinal axis of the post; and, a capture mechanism on the housing which engages the first member to lock the post to the housing when the post is at least partially received in the housing and in one of one or more lock positions relative to the housing.

Preferably, the lock further comprises a release mechanism coupled at one end to an actuator supported by the post and coupled at an opposite end to the first member, the actuator switchable between a first state where the first member can automatically engage the capture mechanism by action of the bias mechanism when the post is in one of the lock positions, and a second state where the actuator pulls the release mechanism in a direction of the longitudinal axis and retracts the first member against the bias mechanism where the first member disengages or is unengagable with the capture device.

Preferably, the release mechanism comprises a tether having a first length extending internally along a portion of the length of the post, and a second length near the first member which extends in the transverse direction.

Preferably, the actuator comprises a cam or lever to which the one end of the release mechanism is attached.

Ros/keep/speci/complete/P54305 Retractable Bollard 21/09/04 6 Preferably, the lock further comprises a surface about which the release mechanism turns from the first length into the second length.

Preferably, the surface is an outer circumferential surface of a roller rotatably supported by the post.

Preferably, the actuator is key operated.

Preferably, the actuator is arranged so that when turned by a key to switch the lock to the second state, the lock is maintained in the second state upon withdrawal of the key.

According to a further aspect of the present invention it is provided a bollard comprising: a housing having a first end and a second end, and defining a cavity between the first and second ends; a post extendable from the first end of the housing and adapted to be received at least partially in the housing; and, a lock in accordance with the present invention wherein the first member of the lock is supported by the post and the capture mechanism is provided on the housing, the bollard having a deployed condition where the post is in a first of the lock positions and locked to the housing by the lock with a first length of the post disposed in the cavity and a second length of the post extending from the first end of the housing so that the bollard has a length equal to a distance between the second end of the housing and the first end of the post and, a non-deployed condition where the bollard has a length equal to the distance between the first and second ends of the housing.

Ros/keep/speci/complete/P54305 Retractable Bollard 21/09/04 7 In one embodiment, the cavity is dimensioned such that the post can be substantially wholly disposed in the cavity when the bollard is in the non-deployed condition. In this embodiment when the bollard is in the non-deployed condition, the lock may, but need not necessarily, lock the post to the housing. In order for the post to be locked to the housing when the bollard is in the nondeployed condition the housing is provided with a second capture mechanism located to be engaged by the first member when the post is substantially wholly disposed in the housing.

In an alternative embodiment when the bollard is in the non-deployed condition, the post is wholly removed or withdrawn from the cavity. Thus, in this embodiment the post is located separately from the housing when the bollard is in the non-deployed condition.

Brief Description of the Drawings An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings in which: Figure 1 is a perspective view of an embodiment of the retractable bollard in a retracted state; Figure 2 is a perspective view of the interior of another portion of the retractable bollard with an associated bollard cap removed; Figure 3 is a view of the interior of the top portion of the bollard with the bollard cap attached; Figure 4 is a perspective view of first and second locking mechanisms incorporated in the bollard; Figure 5 is a view from an alternate angle of the locking mechanisms depicted in Figure 4; Figure 6 is an interior view of a bottom portion of the bollard depicting an associated post in a retracted position; Ros/keep/speci/complete/P54305 Retractable Bollard 21/09/04 8 Figure 7 is a schematic representation of another embodiment of the bollard; and, Figure 8 is a schematic representation of a further embodiment of the bollard.

Detailed Description of Preferred Embodiment With reference to the accompanying drawings, a retractable bollard 10 in accordance with an embodiment of the invention comprises a housing 12, a post 14 moveable between a retracted position (shown in Figures 1-3) where the post 14 is substantially wholly disposed within the housing 12, and an extended position (not shown) where a length of the post is extended from the housing 12; and, a counterweight system 16 disposed within the housing 12 and coupled to the post 14 for biasing the post 14 toward the extended position.

The housing 12 comprises a central or main compartment 18 defined by a central elongated sleeve 20 in which the post 14 is retained and first and second side compartments 22 and 24 on each side of the central compartment 18, the compartment 22 being defined by a sleeve 26 and the compartment 24 being defined by a sleeve 28. An upper end of the housing 12 is closed by a cover plate 32 which is provided with a central aperture 34 through which the post 14 can move. The plate 32 extends laterally beyond the sleeves 20, 26 and 28. A length of angle iron 36 is fixed to opposite surfaces near a lower end of the housing 12 and extends transverse to the length of the housing. The angle iron 36 assists in retaining the housing 12 within the ground.

The post 14 is in the form of a square section metal tube 38 which is closed by a plate 40 at an end adjacent the end of the housing 12 when the post 14 is in the retracted position. However the cross-sectional shape of the post 14 is not critical to the working of embodiments of the Ros/keep/speci/complete/P54305 Retractable Bollard 21/09/04 9 invention and other shapes, most notably but not limited to, circular can be used.

The counterweight system 16 comprises a pair of counterweights 42 (see Figures 2 and 3) both of which are coupled to the post 14 and moveable within the housing 12, and more particularly compartments 22 and 24 of associated sleeves 26 and 28, in a direction opposite the motion of the post 14 as the post 14 is moved between its retracted and extended positions. For example, with reference to Figure 3 where the post 14 is shown in a retracted position, if the post 14 were to be moved to the extended position so that it moves in an upward direction the counterweights 42 would move in an opposite downward direction. Similarly, assuming the post 14 were fully extended, and it was desired to return the post 14 to the retracted position, the post 14 would move in a downward direction and the counterweights 42 move simultaneously in an upward direction.

It should be noted that while the counterweight system 16 is depicted as comprising two counterweights, obviously other embodiments may use a different number of counterweights.

for example in one variation the counterweight system 16 may have only a single counterweight and the housing 12 provided with only a single (or first) compartment to house the single counterweight. What is of importance is the presence of a counterweight to assist in the lifting and lowering of the post 14 not the specific number of counterweights.

The counterweights 42 are attached by the respective straps 44 to the post 14. The straps 44 pass about rollers or pulleys 46 mounted on respective axles 48 that in turn are supported by respective brackets 50 attached at the upper end of the sleeves 26 and 28 respectively. The rollers may be in the form of bobbins, having a raised rim at each axial end. The straps 44 pass through apertures 52 provided adjacent the rollers 46 formed in the sleeves 20, 26 and 28, Ros/keep/speci/complete/P54305 Retractable Bollard 21/09/04 10 and extend into the central compartment 18 on either side of the post 14. The distal end of each strap 44 is passed into the post 14 through a corresponding aperture 54 near a lower end of the post 14 and engaged by a respective buckle 56 (see Figure 6) to thereby attach them to the post 14.

However, in one variation a bar can be attached to the lower end of the post 14 about which the straps 44 can be looped and stitched back onto themselves to couple the straps to the post. The bar may be supported by an end cap fitted to the bottom of the post 14. Naturally other types of couplings or tether can be used such as ropes, wires and wire cables.

The counterweights 42 bias the post 14 toward the extended position by virtue of gravity acting on the counterweights 42 urging them to move toward a lower end of the housing 12 which by virtue of the connection via the straps 44 urges the post 14 toward the extended position. By forming the counterweights 42 to have a combined mass approximately the same as that of the post 14 it would be appreciated that very little external force is required to be applied to the post 14 in order to lift it to the extended position.

Indeed, after an initial external physical pull on the post 14, the bias provided by the counterweights may be sufficient to fully extend the post 14 without the need for any further lifting or pulling on the post 14 by a user.

Similarly, when it is desired to retract the post 14 from the extended position to the retracted position, the counterweights 42 by continuing to bias the post 14 in the opposite direction effectively support the post 14 as it is retracted preventing it from free falling at an acceleration of 1g. While gravitational forces are acting on the post 14 urging it toward the retracted position, the gravitational force is effectively being countered by the motion of the counterweights in an opposite direction against gravitational force.

Ros/keep/speci/complete/P54305 Retractable Bollard 21/09/04 11 With the combined mass of the counterweights 42 about the same as the mass of the post 14, the effects of gravity are substantially balanced by the counterweight thereby resulting in the post 14 either moving of its own accord very slowly back into the housing 14 or requiring only a light push in a downward direction by an operator to cause it to move to the retracted position.

The bollard 10 further comprises first and second locking mechanisms for releasably locking the post 14 in the extended and retracted positions.

Referring to Figures 4 to 6, the first locking mechanism 58 locks the post 14 in the extended position. The locking mechanism 58 comprises a first biased member in the form of a spring biased pin 60 which is held within a tube 62 extending transversely of the post 14 and supported in a bracket assembly 64 attached on the inside and at a lower end of the post 14 (see in particular Figure The pin engages a capture means in the form of a hole (not shown) formed transversely through an upper end of the sleeves and 28. Thus when the post 14 is in the extended position, the pin 60 will by virtue of its bias automatically extend into the hole thereby automatically locking the post 14 to the extended position.

The locking mechanism 58 includes a cord 66 which acts as a release mechanism to disengage the pin 60 from the hole in order to allow the post 14 to be returned to the retracted position. The cord 66 is attached at one end to an actuator in the form of a key operated cam 68 on the inside near an upper end of the post 14. An opposite end of the cord 66 passes about a pulley 70 rotatably mounted in the bracket assembly 64 and coupled to the pin 60, typically by a grub screw clamping the cord 66 in an axial passage in the pin The cam 68 is operated by a key that turns the cam 68 Ros/keep/speci/complete/P54305 Retractable Bollard 21/09/04 12 to pull on the cord 66 thereby retracting the pin 60 from the hole, disengaging the locking mechanism 58 and allowing the post 14 to be returned to its retracted position.

In an alternative embodiment, the tube 62 and bracket assembly 64 may be formed as a single integral unit from a plastics material in the general shape of a cylinder with a pair of arms extending at one end between which the roller is rotatably retained. The cylinder will have an axial passage through which the cable 66 can pass and at an opposite end to the bifurcated arms, a recess for retaining the pin 60. It is further envisaged that the pin 60 could be in the form of a stainless steel rod provided with an axial passage into which the cable 66 is fed and having a grub screw or other locking mechanism that can engage the cable 66 to lock it onto the pin 60. Also, in Figure 3 the cord 66 is shown as attached to the cam 68 by a ring 69.

However, in an alternative embodiment a small pulley or roller can be rotatably coupled to the end of cam 68 and the cord 66 looped around the pulley or roller and attached back onto itself.

A second separate releasable locking mechanism 72 is provided to lock the post 14 in the retracted position. The second locking mechanism 72 comprises a second member in the form of a tongue 74 that passes through a hole 77 formed in the post 14 and which is biased toward a locked state by a spring 76 and an aperture 78 (see Figure 6) formed in the sleeves 20 and 28 which engages the tongue 74 when the post 14 is in the retracted position. The tongue 74 is provided at an end of a transversely extending plate 80 which in turn is mounted on a longitudinally extending rod 82. The rod 82 extends at its upper end through a bracket 84 attached on the inside near the top of the post 14. The upper end of the rod 82 passes through the bracket 84 and is formed with a tang 86 that can be engaged by a key (not shown) for rotating the rod 82 about its longitudinal axis. To Ros/keep/speci/complete/P54305 Retractable Bollard 21/09/04 13 facilitate engagement of the key with the tang 86, the plate is provided with a hole 88 through which the key can pass. The spring 76 acts on the rod 82 biasing the tongue 74 toward the locked state where it extends into the aperture 78. Thus, when the post 14 is fully retracted, the tongue 74 automatically extends into the aperture 78 thereby self-locking the post 14 in the retracted position.

In a variation of the above arrangement, the spring 76 can be moved to an upper end of the post 14 and coupled between a tab (not shown) extending transversely of the rod 82 and a small bracket welded or otherwise attached to the inside of the post 14. In this variation, the bracket 84 can be removed and replaced with a smaller flange depicted by phantom line 85 and a small L-shaped bracket (depicted by phantom line 87) to support the cam 68. This arrangement allows easy visual inspection inside of the post 14 upon removal of the end cap or plate Figure 7 depicts a further embodiment of the bollard which comprises a housing 12' and post 14'. The housing 12' is disposed in the ground 15 and has a first end 17 substantially at ground level and an opposite second end 19 disposed beneath ground level. The housing 12' defines a cavity 21 in which the post 14' is received. When the bollard 10' is in a deployed or extended condition, a first length of the post 14' is disposed in the cavity 21 and a second length of the post extends from the first end 17.

The cavity 21 is dimensioned so that when the bollard 10' is in a non-deployed or retracted condition, the post 14' can be fully retracted into the housing 12' so that an upper end 23 of the post 14' is substantially flush with or below the end 17 of the housing 12'. The bollard 10' also comprises a first locking mechanism 58' which is of similar construction to the locking mechanism 58' depicted in the embodiment shown in Figures 1 to 6 together with a capture mechanism in the form of a recess 25 formed in the housing 12. The Ros/keep/speci/complete/P54305 Retractable Bollard 21/09/04

M

14 locking mechanism 58' comprises a release mechanism in the form of a cable or tether 66' that is coupled at one end to a key operated cam or actuator 68' and at an opposite end to a spring biased pin 60'. The actuator 68' has a first state where the pin 60' can automatically engage the recess when in alignment therewith, which corresponds to the post 14' being locked in the deployed condition, as depicted in Figure 7. However, the actuator 68' can also be switched to a second state, where it pulls the cord or tether 66' upwardly in a general direction of longitudinal axis A of the post 14' thereby retracting the pin 60' to disengage the pin 60' from the recess 25. Moreover, the actuator 68' can be formed in the manner so that when switched to a particular state by a key, and the key is removed, the actuator remains in that state. Alternatively, the actuator 68' can be formed so as to automatically return to the first state upon release or withdrawal of the key. The actuator 68' of the embodiment depicted in Figures 1 to 6 may also be formed in this manner.

The housing 12' may also include a second recess 25' near the lower end 19 for capturing the pin 60' when the bollard is in the non-deployed condition. This allows the post to be locked in the non-deployed condition and prevent unauthorised withdrawal. When the second recess 25' is included, a keyhole for the actuator 68' needs to be moved to the plate 40 to allow release of the pin 60' from the recess 25' when moving the post 14' from the retracted to the extended position.

The operation of the bollard 10' will now be described.

Figure 7 depicts the bollard 10' in the deployed condition with a first length of the post 14' disposed in the cavity 21 and a second length extending from the first end 17 of the housing 12'. The cavity 21 and thus the housing 12' are dimensioned so that the bollard 14' when in a non-deployed condition it can be fully retracted into the housing 12' Ros/keep/speci/complete/P54305 Retractable Bollard 21/09/04 15 In the description of this embodiment, it is assumed that the actuator 68' is of a simplest kind where the position of the actuator 68' is not maintained upon withdrawal of the key. Thus, when no key is inserted into the actuator 68' and turned, the pin 60' is ordinarily biased outwardly of the post 14' To retract the post 14' from the deployed condition into the housing 12', the key is inserted into the actuator 68' and turned to pull the cord 66' upwardly to disengage the pin from the recess 25. The post 14' will now fall or can be lowered by hand until it reaches the end 19 of the housing 12'. If the housing 12' is provided with the recess the pin 60' will automatically engage the recess and thereby lock the post 14' automatically in the nondeployed condition. When it is next required to deploy the post 14' (and assuming for the present time that the housing 12' does not include the recess the user will simply grab the post 14' and slide it in an upward direction.

Eventually the post 14' will reach the locked position where the pin 60', being biased by a spring, will automatically extend into the recess 25 to lock the post 14' in position.

Thus, the pin 60' will automatically engage the recess without the need for an operator to manipulate or otherwise turn the actuator 68'. It will also be appreciated that the automatic engagement of the pin 60' in the recess 25 will prevent unauthorised removal of the post 14' from the housing 12'.

In the event that the housing 12' is provided with the second recess 25', then in order to extend the post 14' to the deployed condition, an operator must first insert a key into the actuator 68' and turn it in an appropriate manner to retract the pin 60' from the recess Figure 8 depicts a further embodiment of the bollard The bollard 10" differs from the bollard 10' only in terms Ros/keep/speci/complete/P54305 Retractable Bollard 21/09/04 16 of the configuration of the housing 12'. With the embodiment 10", the housing 12" is shortened and of a length only required to house a lower length of the post 14" when in the deployed condition. That is, the housing 12" is not of a sufficient length to fully house or accommodate the post 14" in a non-deployed condition. Thus, when the bollard 10" is being used but is not required to deploy the post 14", the post 14" is simply wholly removed from the housing 12" and stored separately.

It will be further appreciated that the bollards 10' and do not use or incorporate counterweights, nor do they use the second locking mechanism 72.

All modifications and variations of the above-described embodiments that would be obvious to a person of ordinary skill in the art are deemed to be within the scope of the present invention, the nature of which is to be determined from the above description and the appended claims.

In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

Ros/keep/speci/complete/P54305 Retractable Bollard 21/09/04

Claims (24)

1. A retractable bollard comprising: a housing; a post moveable between a retracted position where the post is substantially wholly disposed within the housing and an extended position where a length of the post is extended from the housing; and, at least one counterweight coupled to the post, wherein the at least one counterweight moves in a direction opposite to a direction of motion of the post as the post is moved between the retracted and extended positions.

2. A retractable bollard comprising: a housing having a main compartment and an adjacent compartment; a post moveable between a retracted position where the post is substantially wholly disposed within the main compartment and an extended position where a length of the post is extended from the main compartment; and, a first counterweight disposed in the first compartment and coupled to the post, the first counterweight and the post relatively juxtaposed so that when the post moves in a direction from the retracted position to the extended position, the counterweight moves in an opposite direction and applies a force to the post that counters gravitational force acting on the post.

3. A retractable bollard according to claim 1 or claim 2 comprising first and second counterweights, one of each coupled to opposite sides of the post.

4. A retractable bollard according to claim 1 or claim 3 wherein the housing comprises a main compartment in which the post is retained and first and second side compartments, one on each side of the main compartment, wherein the first Ros/keep/speci/complete/P54305 Retractable Bollard 21/09/04 18 counterweight is located in the first compartment and the second counterweight is located in the second compartment.

A retractable bollard according to any one of claims 1 to 4 further comprising a first releasable lock for releasably locking the post in the extended position.

6. A retractable bollard according to claim 5 wherein the first releasable lock is automatically deployed when the post reaches the extended position.

7. A retractable bollard according to claim 6 wherein the first releasable lock comprises a first member biased toward a locked state and a first capture means provided in the housing and in a position whereby the first member engages the first capture means when the post is in the extended position to thereby lock the post in the extended position.

8. A retractable bollard according to claim 7 wherein the first member is supported by the post.

9. A retractable bollard according to claim 8 wherein the first member comprises a pin or rod and a bias mechanism for biasing the pin or rod into engagement with the first capture means.

A retractable bollard according to claim 9 wherein the first releasable lock comprises a release mechanism coupled to the first member to disengage the first member from the first capture means against the bias of the bias mechanism.

11. A retractable bollard according to any one of claims to 10 further comprising a second releasable lock for releasably locking the post in the retracted position. Ros/keep/speci/complete/P54305 Retractable Bollard 21/09/04 19

12. A retractable bollard according to claim 11 wherein the second releasable lock is automatically deployed when the post is in the retracted position.

13. A retractable bollard according to claim 12 wherein the second releasable lock comprises a second member biased toward a locked state and a second capture means provided in the housing at a position whereby the second member is engaged by the second capture means when the post is in the retracted position to thereby releasably lock the post in the retracted position.

14. A lock for a bollard having a housing and a post adapted to be at least partially received in the housing, the lock comprising: a first member supported by the post and a bias mechanism for biasing the first member to extend from the post in a direction transverse to a longitudinal axis of the post; and, a capture mechanism on the housing which engages the first member to lock the post to the housing when the post is at least partially received in the housing and in one of one or more lock positions relative to the housing.

15. A lock according to claim 14 further comprising a release mechanism coupled at one end to an actuator supported by the post and coupled at an opposite end to the first member, the actuator switchable between a first state where the first member can automatically engage the capture mechanism by action of the bias mechanism when the post is in one of the lock positions, and a second state where the actuator pulls the release mechanism in a direction of the longitudinal axis and retracts the first member against the bias mechanism where the first member disengages or is unengagable with the capture device. Ros/keep/speci/complete/P54305 Retractable Bollard 21/09/04 20

16. A lock according to claim 15 wherein the release mechanism comprises a tether having a first length extending internally along a portion of the length of the post, and a second length near the first member which extends in the transverse direction.

17. A lock according to claim 16 wherein the actuator comprises a cam or lever to which the one end of the release mechanism is attached.

18. A lock according to any one of claims 15 to 17 wherein the actuator is arranged so that when turned by a key to switch the lock to the second state, the lock is maintained in the second state upon withdrawal of the key.

19. A bollard comprising: a housing having a first end and a second end, and defining a cavity between the first and second ends; a post extendable from the first end of the housing and adapted to be received at least partially in the housing; and, a lock in accordance with any one of claims 15 to 18, wherein the first member of the lock is supported by the post and the capture mechanism is provided on the housing, the bollard having a deployed condition where the post is in a first of the lock positions and locked to the housing by the lock with a first length of the post disposed in the cavity and a second length of the post extending from the first end of the housing so that the bollard has a length equal to a distance between the second end of the housing and the first end of the post and, a non-deployed condition where the bollard has a length equal to the distance between the first and second ends of the housing.

A bollard according to claim 19 wherein the cavity is dimensioned such that the post can be substantially wholly Ros/keep/speci/complete/P54305 Retractable Bollard 21/09/04 21 disposed in the cavity when the bollard is in the non- deployed condition.

21. A bollard according to claim 20 wherein said lock locks said post to said housing in said non-deployed condition.

22. A bollard according to claim 21 wherein the housing is provided with a second capture mechanism located to be engaged by the first member when the post is substantially wholly disposed in the housing.

23. A bollard according to claim 19 wherein when the bollard is in the non-deployed condition, the post is wholly removed or withdrawn from the cavity.

24. A bollard substantially as herein described with reference to and as illustrated in the accompanying drawings. A lock for a bollard according to claim substantially as herein described with reference to and as illustrated in the accompanying drawings. Dated this 21st day of September 2004. IMAGE BOLLARDS PTY LTD By Its Patent Attorneys GRIFFITH HACK Fellows Institute of Patent and Trade Mark Attorneys of Australia Ros/keep/speci/complete/P54305 Retractable Bollard 21/09/04