GB2504548A

GB2504548A - Compression post foot connection

Info

Publication number: GB2504548A
Application number: GB1213854.1A
Authority: GB
Inventors: Abdul Mukith; Luke Smith
Original assignee: A Fax Ltd
Current assignee: Three Smith Group Ltd
Priority date: 2012-08-03
Filing date: 2012-08-03
Publication date: 2014-02-05
Also published as: GB201213854D0

Abstract

A post connection is provided wherein a post is connected to a foot anchor internally. The post and foot anchor are secured together using friction, with the foot anchor in a state of compression. For instance, the foot anchor includes a rigid central section and a compressible outer sleeve that fits tightly about the rigid central section. Here, the post is forced on to the outside of the compressible sleeve. The internal dimensions of the post, the dimensions of the compressible sleeve, and the external dimensions of the rigid central section are sized so as to make a tight compression joint. It has been found that such a joint forms an extremely reliable and strong connection between the post and foot anchor. Furthermore, the foot anchor remains substantially hidden in use.

Description

Improvements in and Relating to Post Connections The present invention relates to the connection of posts and the like to a surface. The invention is particularly suitable to the connection of posts to a ground in a barrier arrangement.

Barrier arrangements are known where a series of posts are installed anchored to a ground surface. The posts can be interconnected by rails or the like to form a pedestrian, vehicular or other barrier. In such systems, in the event of an impact, the forces are transferred through the post and into the ground. The strength of the connection to the ground surface is therefore important and typically a strong anchor connection is required.

It is advantageous from a cost and reliability point of view that the posts and rails are formed from a high strength plastic material. Typically, these parts are extruded and cut to size. Whilst the posts can be installed by burying part of the extrusion to anchor it directly to the ground, this is often not possible or desirable. Rather, the posts are usually secured to a foot plate that is then secured to the ground. Known foot plates are typically formed from metal such as steel. Here the footplates have a sleeve part that extends a substantial way up the length of the extrusion in order to receive and secure the plastic post. A plate part extends from the sleeve part at a generally orthogonal angle to the length of the sleeve so as to be parallel to the ground when the post is upright. The plate part extends outwards from the sleeve so that fixings can be secured there though to anchor the foot plate to the ground. For instance, typically the plate part is square and bolts are secured through holes in each corner.

Often, the weakest point of known post and footplate systems is the connection between the plastic post and metal footplate. Furthermore, the footplate remains visible and requires finishing. Yet further, when the footplates are secured to the ground at an off-set to a central axis of the post, the ground anchors are susceptible to greater tension and increased pull out forces are applied that act to pull the post from the ground when impacted.

It is an aim of the present invention to solve at least one of the above or other disadvantages. It is a further aim to provide a post connection that can be anchored to the ground in an improved manner, and in particular, in a manner wherein the post substantially retains its external appearance. It is a further aim to provide a post connection having increased strength when the post or rail is impacted.

According to the present invention there is provided a post connection and a method of connecting a post to the ground as set forth in the appended claims. Other features of the invention will be apparent from the dependent claims, and the description which follows.

According to an exemplary embodiment, there is provided a post connection wherein a post is connected to a foot anchor internally. Here the post is at least partially hollow at a foot end and the foot anchor is secured to said foot of the post. The foot anchor can be secured to the ground in a conventional manner or, advantageously, through the alternative embodiment herein described. It will be appreciated that the post connection is particularly suitable for use with an extruded post, such as a plastic post. Here, the post is entirely hollow, which includes having ribs or webs for strength. However, the exemplary embodiments work equally well with solid or other types of post having a hollow portion formed at the foot end.

In a particularly exemplary embodiment, the post and foot anchor are secured together using friction. In this case, importantly, a portion of the foot anchor in contact with an inside of the post is softer than the post when under operating conditions. For instance, suitably the foot anchor includes a rigid central section and a compressible outer sleeve that fits tightly about the rigid central section. Here, the post is forced on to the outside of the compressible sleeve. The internal dimensions of the post, the dimensions of the compressible sleeve, and the external dimensions of the rigid central section are sized so as to make a tight compression joint. It has been found that such a joint forms an extremely reliable and strong connection between the post and foot anchor. Furthermore, the foot anchor remains substantially hidden in use. Whilst the foot anchor may be formed from a single material wherein the compressible outer sleeve and rigid central section are a single piece, the rigid central section provides a suitable connection point for a ground anchor connection. In this case, the rigid central section with reduced compressibility as compared to the compressible outer sleeve, which is used to give the compression joint strength, which would otherwise result in the ground anchor having reduced rigidity and strength.

In one exemplary embodiment, the foot anchor is bulbous. That is, the pad of the foot anchor received by the post has a greater thickness at a point spaced from a point nearer the foot or top of the post and preferably from both a point nearer the foot and a point nearer the top. The post may be pre-shaped to follow the shape of the foot anchor. That is, the post is moulded prior to connection to the foot anchor to have, for instance, a bulbous foot. However, dependant on the material properties and the forces involved, in some instances it may be possible to form the foot of the post to mould about the foot anchor during connection of the two.

In an exemplary embodiment, a method of connecting the post to the foot anchor is provided. Here the method involves urging the post onto the foot anchor to form a strong compression joint. In a preferable embodiment, the extruded post may be heated to improve the malleability of the post to the foot anchor. In this example, whilst heated the foot anchor is introduced into the pipe. The foot anchor may be pre-assembled or may be introduced one after the other. In a particularly exemplary embodiment, a rigid former is arranged about the foot of the post whilst the foot anchor is introduced to the post.

The foot anchor may be arranged to be secured to the ground using ground anchors in the usual manner. In this instance, the rigid central section includes side extensions that extend outwards from the post when assembled to the foot anchor. It will be appreciated that the side extensions would include holes or be otherwise adapted for the ground anchors.

However, according to exemplary embodiments, the foot anchor is secured to the ground by a ground anchor substantially central to the post. For instance, the foot anchor may include an integral, central fixing or may include a central fixing location through which a rotatable ground anchor is received. Rotatable ground anchors are known such as threaded sockets, or resin or mechanical expansion nuts and bolts. The premise behind rotatable ground anchors is to rotate one part relative to the other. When the ground anchors are easily accessible, this is straighiforward using tools. However, when the ground anchor is central to the post, the tools need to be substantially the length of the post, if not longer. Indeed, in instances when the post is not hollow, or the top of the post is covered, they become inaccessible. Consequently, it is proposed in the exemplary embodiments to provide at least one aperture through the foot anchor and for the post, which through which a tool can be inserted to rotate one of the parts of the rotatable ground anchor. For instance, the tool may be used to rotate the assembled post and foot anchor where the ground anchor is integral thereto. Alternatively, the tool may be used to engage a ground anchor that is installed in a rotatable manner through a hole in the foot anchor.

Advantageously, a single central anchor reduces the number of ground anchors necessary to fix the foot anchor to the ground. Furthermore, the central location assists in reducing the pull out forces experienced by the ground anchor in the event of impact.

In exemplary embodiments, the apertures extend from one side of the post to the other so that a tool can be inserted to extend from both sides. In yet further exemplary embodiments, an aperture may be provided either side of a centre of the post in order to improve and balance the turning forces.

For a better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings in which: Figure 1 is a perspective bottom view of a post assembly according to a first exemplary embodiment; Figure 2 is a cross-sectional perspective view through a bottom end of a post assembly of an exemplary embodiment and along a central axis; Figure 3 is a cross-sectional perspective view through a foot anchor according to an exemplary embodiment; Figure 4 is a perspective side view of an exemplary post for use in forming a post assembly; Figure 5 is a view of one half of an exemplary former used during the joining process of a foot assembly and post; and Figure 6 is a perspective view of an exemplary ground anchor for use in securing a foot anchor to a ground.

Referring to Figure 1, an exemplary post assembly 100 is shown. The post assembly is formed from a post 110 and a foot anchor 120. The post is formed on the outside of the foot anchor 120. Advantageously, because the post is compressed onto the outside of the foot anchor 120, the foot anchor 120 remains substantially hidden by the post 110. In the exemplary embodiments, the post is held to the foot anchor by friction. Specifically, the post is compressed onto the foot anchor 120. Here, the foot anchor acts to apply an outwardly force in an attempt to expand but is constrained in doing so by the surrounding post 110. It has been found that this assembly of a post to a foot anchor can provide an extremely high-strength bond between the post and foot anchor and is particularly useful in providing a post assembly for use in a traffic or pedestrian barrier system.

In more detail, the connection between the foot anchor 120 and post 110 is shown in Figure 2. As will be explained herein, the post is formed from an extrusion. Suitably in exemplary embodiments, the post is an extruded plastic, which provides a naturally aesthetic surface finish as well as being corrosion and abrasion resistant. Typically, the extrusion forms a hollow tube with constant wall thickness. Although the post 120 is shown having a circular cross-section, the foot anchor and other parts can be adapted for use with ovoid, square, rectangular and any other cross-sectional design as required by the post designers. Further more, although the post 110 is shown as being hollow, all that is necessary is for a foot region 112 of the post to be provided with a hollow area 114 for receiving the foot anchor 120.

Consequently, the post 110 may be substantially solid above the foot region, or may include webs or ribs for strength.

Still referring to Figure 2, the fool anchor 120 includes a rigid central section 130 having a compressible outer sleeve 140. The rigid central section 130 provides a stiff centre to the foot anchor and provides a stiff support to the compressible outer sleeve 140 to prevent inward movement of the outer sleeve. Suitably, the rigid central section 130 may be formed from a metal, such as steel or the like or may be formed from a rigid plastic material similar to that of the post. The outer sleeve is sized so as to fit tightly onto an outside of the central section 130. A particularly suitable material for the outer sleeve has been found to be rubber, however, what is thought to be important rather than the specific material is that the outer sleeve, under normal conditions of operating, is softer than the post. An outer surface of the compressible sleeve 140 is sized so as to fit tightly within the foot of the post 110. As will be appreciated, the compressible sleeve is sized so as to be at least partially compressed when the post 110 is forced there over. However, the possibility of additionally using an adhesive or further material between the post and foot anchor is not excluded.

As can be seen in Figure 2, a ground anchor 150 is used to secure the foot anchor, and therefore the post assembly to the ground. As will be herein described, the foot anchor can be secured in any known manner. In Figure 2. an exemplary embodiment is shown wherein the post assembly is secured using a single, central ground anchor 150. Also, although the ground anchor is shown as extending through an aperture in the central section 130, the ground anchor 150 may alternatively be integral to the central section 130, such as an integral threaded hole or an integral protruding threaded section. It will therefore be appreciated that what is important is for the post assembly to include a means to secure the central section to a ground surface. With the central section secured in an adequate manner, the post 110 automatically becomes secured to the ground through the exemplary connection between the foot anchor 120 and post 110.

Referring to Figure 3, an exemplary foot anchor 120 is shown. Suitably, the foot anchor comprises a rigid central section 130 and compressible outer sleeve 140 as herein described. In this exemplary embodiment, the central section 130 is generally cup-like having a base 132 and upwardly extending side walls 134. The sidewalls 134 are preferably parallel and arranged to extend parallel to a central axis of the post 110. Again, although the central section 130 is shown as having a generally circular cross-section, alternative shapes and configurations are envisaged and can be easily adopted by simple rearrangement of the matching shapes. In an exemplary embodiment, the base 132 includes an aperture through which a ground anchor 150 can be arranged. Alternatively, the ground anchor 150 may be integral. For instance, the hole through the base 132 may be threaded for coupling to a threaded connection anchored in the ground. Alternatively, rather than a hole, the base 132 may be provided with a threaded protrusion for coupling to a threaded hole or the like in the ground surface. The central section is shown with an open top 136. As will be seen, this enables, in one embodiment, a tool to be inserted from the top of the post assembly 100 to operate the ground anchor 150. However, in other embodiments, where access to the ground anchor 150 from the top of the post assembly 100 is not required, the central section may be substantially solid or may include ribs or webbing for strength. A flange 138 is optionally formed around the open top 136. here, the flange extends outwardly from the side walls 134 and can provide a stop for the compressible outer sleeve 140 to abut.

The compressible outer sleeve is also described in more detail by way of example to the exemplary embodiment shown in Figure 3. The outer sleeve 140 fits over the central section.

Preferably, the outer sleeve is sized so as to have to be urged on to the central section by driving the two parts together. It will be appreciated that here, the two parts are moved towards each other along a central axis. Additionally or alternatively to abutting a flange on the central section, the outer sleeve may also be generally cup-shaped so that a closed bottom surface 142 also covers the base 132 of the central section 130. In this instance, when the ground anchor 150 is tightened, the bottom surface 142 is trapped between the base 132 of the central section and the ground surface. This allows the post assembly to be squeezed onto the ground by tightening the ground anchor, the compression of the bottom surface acting as a damper. The generally cup-shaped outer sleeve includes upwardly extending side walls 144. Inside surfaces of the upwardly extending walls are shaped and sized to envelop the central section 130. Although outer surfaces of the upwardly extending walls 144 that compress against the insides of the post 110 may be parallel, preferably the outer surface bulge. In this instance the outer surfaces bulge at a point spaced from an open end 146 or the bottom 142. However, in the exemplary embodiment shown in Figure 3, the outer surfaces bulge in-between both the open end 146 and bottom 142.

Figure 4 shows an exemplary post 110 prior to joining to a foot anchor 130. The post shown here has been preformed to include a bulge at the foot region 112. The bulge 112 corresponds to the bulge of the foot anchor. This pre-forming reduces the risk of splitting when the post 110 is forced over the foot anchor 120. However the pre-forming of the bulge may not be necessary in all occasions. The method of joining the post 110 and foot anchor is yet further enhanced in an exemplary method by heating the foot region 112 before forcing the foot anchor into the post. In this instance, and when the post is formed from a plastic material having a melting point of around 152°C, the exemplary methods have heated the foot region 112 to between 100-140°C. Thus, it is thought important that the heating maintains the post beneath its melting point but enables the post to be soft and pliable. In the exemplary embodiments after any preferable heating and pre-forming steps, the foot anchor is pushed onto the foot region of the post 110. Although in one exemplary embodiment, the foot anchor 120 is pre-assembled, in another exemplary embodiment, the central section and outer sleeve are inserted simultaneously from either end of the post 110. When the post cools, the post contracts onto the foot anchor and compresses the outer sleeve thereby forming the connection there between.

In the exemplary methods, a former is suitably used on the outside of the foot region 112 of the post 110. A suitable former 160 is shown in Figures by way of example. Suitably, the former 160 forms a split part mould that has an internal shape corresponding to the shape of the foot region 112. Consequently, when the split part mould is clamped about the foot region 112, the former 160 restricts expansion of the foot region 112.

As will be appreciated, if the outer sleeve 140 does not include a closed end, the central section can abut the ground surface directly. This also allows an outwardly extending flange or flanges to extend past the extend of the post and enables a traditional fixing to be employed to secure the central part to the ground surface. For instance, the base of the central section may be a plate having dimensions greater than the external dimensions of the post 110.

However, in the exemplary embodiments and in accordance with an embodiment not necessarily dependent on the previous exemplary embodiments wherein the post is internally fixed to the foot anchor, the toot anchor 120 is secured to the ground surface by a central ground fixing. That is, the foot anchor is secured to the ground at a point coincident with the central axis of the post 110. Whilst one exemplary method comprises using a long tool to access the fixing from the top of the post, in the particularly exemplary embodiments, the ground anchor 150 is activated through an aperture formed in the post assembly.

When the ground anchor 150 is integral to the foot anchor 120, the aperture can be formed in the post. This allows a tool to be inserted into the aperture and generally perpendicular to the post's central axis. Rotation of the post assembly can therefore be achieved using the tool as a handle. Here the aperture may extend through the post 110.

Alternatively, when the ground anchor 150 needs to be rotated within the post assembly 100, the aperture may be formed through the post assembly so that the tool can be inserted through the aperture to engage the ground anchor. Here, as shown in the exemplary embodiment of Figure 6, the ground anchor 150 may include in a head of the ground anchor, a corresponding aperture 152 via which the tool engages the ground anchor. Thus the tool can be used to rotate the ground anchor, and therefore the threaded protrusion 154 to engage and couple the corresponding part anchored in the ground surface.

Although preferred embodiment(s) of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made without departing from the scope of the invention as defined in the claims.

Claims

Claims 1. A post assembly comprising a post and a foot anchor, wherein the foot anchor is connected to the inside of the post in a state of compression.
2. The post assembly of claim 1, wherein the foot anchor bulges.
3. The post assembly of any of claims I or 2, wherein the foot anchor includes a central section and a compressible outer sleeve.
4. The post assembly of any of claims 1 to 3, wherein the foot anchor is arranged to connected to a ground surface at a central location relative to an axis of the post.
5. The post assembly of claim 4, wherein the foot anchor includes an integral ground anchor.
6. The post assembly of claim 5, wherein an aperture is formed in the post assembly so that a tool is able to be inserted into the aperture and at an angle to the central axis of the post to rotate the post assembly.
7. The post assembly of claim 4, wherein the foot anchor includes a hole for receiving a ground anchor.
8. The post assembly of claim 7, wherein the post assembly includes an aperture so that a tool is able to be inserted into the aperture and at an angle to the central axis of the post in order to engage and rotate the ground anchor.
9. A method of connecting a post to a foot anchor to form a post assembly of any of claims ito 8, the method comprising forcing a foot anchor into a hollow of a post so that the two parts are held together under compression.
iO. The method of claim 9, wherein the method comprises heating a foot region of the post prior to inserting the foot anchor.
ii. The method of claim 9 or 10, wherein the method comprises inserting a central section from a top of the post and a compressible outer sleeve from the bottom of the post so that the post, outer sleeve and central section simultaneously engage said respective parts.
12. The method of any of claims 9 to 11, wherein the method comprises arranging a former about the outside of a foot region of the post during connection of the post and foot anchor.
13. A post assembly comprising a post and a foot anchor, wherein the foot anchor is connected to either an inside of the post or an outside of the post, the foot anchor being arranged to be connected to a ground surface at a central location relative to an axis of the post.
14. The post assembly of claim 13, wherein the foot anchor includes an integral ground anchor.
15. The post assembly of claim 14, wherein an aperture is formed in the post assembly so that a tool is able to be inserted into the aperture and at an angle to the central axis of the post to rotate the post assembly.
16. The post assembly of claim 13, wherein the foot anchor includes a hole for receiving a ground anchor.
17. The post assembly of claim 16, wherein the post assembly includes an aperture so that a tool is able to be inserted into the aperture and at an angle to the central axis of the post in order to engage and rotate the ground anchor.
18. A method of installing a post assembly of any of claims Ito Sand 13 to 17, wherein the method comprises inserting a tool into an aperture of the post assembly and using the tool to rotate the post assembly in order to tighten a ground anchor securing the foot anchor to the ground surface.
19. A post assembly or method substantially as herein described and with reference to the Figures.