GB2386918A - Post structure - Google Patents

Abstract

The post structure, particularly for use as a traffic bollard etc., includes a foot portion 4 that, in use, is buried in the ground and an upper portion 16 that extends substantially upright, in use, above the ground and which is connected to the foot portion by a flexible portion that allows the upper portion to flex relative to the foot portion. The flexible portion preferably comprises a neck 14 that includes two recesses 12 formed on opposite sides of the post and which have a substantially part-cylindrical surface. The post is preferably formed from plastic in a single moulding operation, either a blow moulding or rotational moulding process, and is at least partially hollow. The foot portion may include a pedestal 8 of increased diameter which is connected to the flexible portion by a portion of increased rigidity that has a cruciform cross-section.

Description

POST STRUCTURE

The present invention relates to a post structure, for example for roadside use, and in 5 particular but not exclusively to a bollard.

Bollards are used in many roadside situations, for example for restricting vehicle movements, marking the edge of a road, controlling access and so on. Generally, bollards are made of a heavy rigid material such as concrete or cast iron, and are set in concrete to provide a physical barrier as well as to provide a visual indication of the boundary of 10 permitted vehicle movement.

Unfortunately, however, although bollards provide a deterrent against unauthorized vehicle movement, they are vulnerable to damage in the event of a collision with a vehicle, even at relatively low speeds. This may result in the bollard being knocked over, in which case it will have to be re-erected at considerable cost, or it may be broken and will have to be 15 replaced. An accidental collision with a rigid bollard can also of course cause considerable damage to the vehicle.

It is an obj ect of the present invention to provide a bollard that is less vulnerable to damage, and is less likely to cause damage to a vehicle, in the event of a collision.

According to the present invention there is provided a post structure including a foot portion 20 that, in use, is buried in the ground and an upper portion that extends substantially upright above the ground, the upper portion being connected to the foot portion by a flexible portion that allows the upper portion to flex relative to the foot portion.

The post structure is able to deform elastically in the event of a collision, but will then return to its original upright state. The post is therefore less vulnerable to damage and it is less 25 likely to be uprooted if a vehicle runs into it. Similarly, the risk of causing damage to the vehicle is significantly reduced. However, in the case of a bollard, it still serves the purpose of marking the boundary of permitted vehicle travel and, since it is also quite stiff and does

not deform easily, it also provides a physical barrier that can be overcome only by applying quite a considerable force.

Advantageously, the flexible portion comprises a neck. The neck may include two recesses formed on opposite side of the post. Preferably, each recess has a substantially part 5 cylindrical surface. We have found that a neck provides that required degree of flexibility, together with an appropriate level of stiffness and an ability to recover once the deforming force has been removed. It also does not detract significantly from the appearance of the post structure.

Advantageously, the upper portion can flex relative to the foot portion through an angle of 10 at least 10 , and preferably at least 30 , and more preferably approximately 90O, without the post structure suffering significant damage. Although an ability to flex through an angle of 90 is preferred, so that a vehicle can knock the post flat without causing significant damage, in certain applications a lower degree of flexibility may be sufficient, for example in situations where the post is unlikely to be struck hard, such as in a car park.

15 The post structure may be made of a plastics material. We have found for example that polyethylene provides a suitable set of performance characteristics.. Preferably, the post structure is manufactured in a single moulding operation, so minimising manufacturing costs.

The post structure may for example be manufactured by blow moulding or a rotational moulding process.

20 Advantageously, the post structure is at least partially hollow. This reduces the weight of the post and helps to increase its flexibility. Alternatively, the post may be solid or filled with a resilient material, for example a plastics foam.

The foot portion may include a pedestal of increased diameter. This serves as an earth anchor and helps to prevent the post from being uprooted. The pedestal may be connected 25 to the flexible portion by a portion of increased rigidity, to ensure that it flexes only at the intended flexible portion. Preferably, the portion of increased rigidity has a cruciform cross section. According to a preferred embodiment of the invention, the post structure comprises a bollard.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a right hand side view of the bollards Figure 2 is a front view of the bollard, 5 Figure 3 is a left hand view of the bollard, Figure 4 is a top view of the bollard, and Figure is an isometric view of the bollard.

The bollard comprises a substantially cylindrical post 2 having a total height of approximately 644mm and a diameter of approximately 1 25mm. The post is hollow and is 10 made of a resilient material, for example polyethylene or polypropylene, for example by blow moulding or rotational moulding.

At the lower end of the post is a foot portion 4 that in use is buried in the ground so as to support the post in an upright position. The upper boundary of the foot portion is marked by a circumferential groove 6 that serves to indicate the ground level when the foot portion 15 is buried to the correct depth. At the lower end of the foot portion a pedestal 8 of increased diameter is provided, which serves as an earth anchor to prevent the bollard from being pulled out of the ground after it has been buried. The upper part 10 of the foot portion 4 above the pedestal 8 has a cruciform shape, which increases its rigidity.

A few centimetres above the foot portion 4 two recesses 12 are formed on the front and rear 20 sides of the post, forming a narrow neck portion 14 that allows the post to bent forwards and rearwards at this point. In the example, the recesses 12 are curved having approximately part-cylindrical surfaces, but it should understood that although this is a preferred profile, other shapes are also possible.

Above the neck portion, the post 2 may have virtually any shape, but in the embodiment 25 shown in the drawings it has substantially cylindrical upper portion 16 with a head portion 18 at the upper end of that portion. The head portion 18 has two flattened faces 20 that may carry reflectors allowing the bollard to be seen easily at night. The bollard shown in

the drawings is designed for use by the side of a road and the faces 20 are set at an acute angle to one another, so that the reflectors are directed to reflect light back towards vehicles travelling in either direction along the road. A further small reflector 22 is provided just above the neck portion and two decorative bands 24 of slightly different diameters are S provided approximately in the middle of the central portion.

We have found that the neck portion 14 is extremely flexible, allowing the bollard to flex through as much as 90 without suffering any damage. It is thus possible for the upper portion 16 of the bollard to be knocked flat against the ground without uprooting the foot portion. When the vehicle has departed, the bollard will spring back to the upright position.

10 The bollard is therefore far less vulnerable to damage and likewise is far less likely to cause significant damage to a vehicle in the event of a collision.

However, although the post is capable of flexing through a large angle without suffering damage, it is also quite stiff and will flex only if quite a large force (for example, the force that might be exerted by a vehicle) is applied to it. Therefore, as well as marking the 15 boundary of permitted vehicle travel, the bollard also provides a physical barrier, which can only be overcome by applying quite a considerable force.

Various modifications ofthe invention are possible. For example, the bollard may be made of various resilient different materials, including plastics materials, natural or synthetic rubber and composite materials, and it may be made using a variety of different 20 manufacturing techniques, including injection moulding, rotational moulding and casting.

It may be solid or filled with another rnateria, for example a foamed plastics material. The shape of the bollard may also be varied and in particular the neck portion and the foot portion may have different forms.

Instead of providing a neck portion, some other method may be used to provide a portion 25 of the bollard with sufficient flexibility to allow the bollard to bend. For example, the bollard may include a flexible portion in which the walls have a concertina form, or are of reduced thickness, or are treated to increase the elasticity of the material, or a made of a different material having increased elasticity.

Further, although it is preferred that the bollard is capable of flexing through an angle of 90 , in certain circumstances it may be sufficient for the bollard to flex through a smaller angle, for example 30 , or even as little as 10 . This will allow the bollard to flex slightly in the event of a very low speed collision, for example when struck by a vehicle whilst 5 parking, without suffering damage or causing damage to the vehicle.

The structure of the bollard as described herein may also be applied to other articles of roadside street furniture such as lamp posts, road signs and traffic lights, to protect them against damage in the event of a collision, or to the support posts of crash barriers, to provide them with a degree of resilience.

1. A, post structure including a foot portion that, in use, is buried in the ground and an 5 upper portion that extends substantially upright above the ground, the upper portion being connected to the foot portion by a flexible portion that allows the upper portion to flex relative to the foot portion.

2. A post structure according to claim 1, wherein the flexible portion comprises a neck.

3. A post structure according to claim 2, wherein the neck includes two recesses 10 formed on opposite side of the post.

4. A post structure according to claim 3, wherein each recess has a substantially part cylindrical surface.

5. A post structure according to any one of the preceding claims, wherein the upper portion can flex relative to the foot portion through an angle of at least 1 OQ, and 15 preferably at least 30 , and more preferably approximately 90 , without the post structure suffering significant damage.

6. A post structure according to any one of the preceding claims, being made of a plastics material.

7. A post structure according to claim 6, being manufactured in a single moulding 20 operation. 8. A post structure according to claim 6 or claim 7, being manufactured by a blow moulding process or a rotational moulding process 9. A post structure according to any one of the preceding claims, the structure being at least partially hollow.

25 10. A post structure according to any one of the preceding claims, wherein the foot portion includes a pedestal of increased diameter.

A post structure according to claim 10, wherein the pedestal is connected to the flexible portion by a portion of increased rigidity.

12. A post structure according to claim 1 1, wherein the portion of increased rigidity has a cruciform cross section.

5 13. A post structure according to any one of the preceding claims, said post structure comprising a bollard.

14. A post structure substantially as described herein with reference to and as illustrated by the accompanying drawings.

Claims (1)

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