Post bases is use at present are of a basic type, in which a massive concrete base is sunk into the ground to support the post. To secure the post in the concrete base, the latter usually has a central hole that is normally slightly conical, so that a post lowered into the hole becomes firmly wedged against the sides of the lower part of the hole. The junction of the post and the base frequently has a collar intended to protect the inside of the base, by essentially preventing the penetration of water and snow. The collar is also intended to ensure a sufficiently strong joint. Usually, if it is intended to lead cables to the post, as in street and traffic light posts, the base has suitable holes, through which the cables can be led into the post.

If an impact strikes a post supported by a solid concrete base, the base is very likely to fracture. The rigidity of the base is also dangerous in a collision. This is mainly due to the fact that, in a collision, the post bends, close to the point of impact, in the direction of the colliding vehicle or similar, causing great damage, and even the loss of human life.

Various kinds of base construction allowing the post to fall, at least to some extent, at an angle, which can even be horizontal, are disclosed, for example, in US patent 4,364,688, in which the constructions are implemented by an essentially cup-shaped counterweight set inside a cup-shaped base and retained by a pin that breaks in a collision. This construction is extremely ponderous in operation and liable to breakage. Due to its expense and complexity, it cannot be widely used as a primary construction for bases.

CH patent 669967 discloses another falling base construction, which is based on a horizontal joint pin and several springs. Large post constructions cannot be implemented by this construction, as it is difficult to control heavy weights with springs. In addition, the invention disclosed only permits falling in one direction. A force acting in an entirely different direction may not make the post fall while a transverse force will have precisely the same effect on the post as it would on a permanently set post.

This invention applies an entirely new philosophy to bases. The intention is to create an extremely collision-friendly base, which permits a flexible collision with the post supported by the base, thus reducing the damage to the vehicle and its occupants. Another intention is to create a base, which is light and easy to handle, and which remains undamaged by an impact with the post it is supporting.

The aforesaid and other advantages and benefits of the invention are achieved in the manner described in the characterizing section of the accompanying Claims.

The following more detailed description of the invention discloses the characteristics of the invention to the reader. In the following, the invention is described with reference to the drawings, which show some embodiments of the invention.

Thus : Figure 1 shows a vertical cross-section of the basic features of one embodiment of a base according to the invention; Figure 2 shows the details of one base according to the invention ; Figure 3 shows a post supported by a base according to the invention in a collision ; and Figure 4 shows another embodiment of a base according to the invention.

Figure 1 shows a vertical cross-section of one embodiment of the invention. In basic principal, the base 1 is formed by a upwardly narrowing jacket surface 2, which may be, for example, shaped as a circular cone, though the shape is not critical. The base also includes a bottom 3, which may be more or less solid or, as described later, bottom 3 may be formed by, for example, discontinuous components in a radial arrangement. In a solid bottom, there should preferably be holes or openings made in it, to allow water that may enter base 1 to exit.

Bottom 3 has an inward protrusion 4, which, in its simplest form, can only be called a bump on the bottom. An upward-pointing pipe-like component 5 rests on protrusion 4, so that protrusion 4 is partly inside pipe 5. In this embodiment, pipe 5 is not as large in diameter as protrusion 4. Pipe-like component 5 penetrates the hole remaining in the uppermost part of the conical jacket surface and extends for a certain distance 5'above the jacket surface 2. Preferably, a watertight seam is made between pipe 5,5'and the opening in the jacket surface, by welding the materials together, or in another suitable manner.

In its operating environment, base 1 according to the invention is in a position, in which the surface 8 of the ground is more or less at, or slightly above, the level shown, but preferably not up to the level of seal 6. The seal can be of any known type, a shrink-plastic sleeve at the seam or, as later described, a permanently welded joint. The visible part 5'of pipe 5 is intended to form a support for the actual post 7, the lower end of post 7 being simply set on top of section 5'. Pipe 5, 5'is made sufficiently long to firmly secure the post.

In an alternative form of installation, base 1 does not include a pipe 5,5'at all, post 7 being pushed instead into the hole in the upper part of cone 1 and set on protrusion 4 on the bottom of base 1. Naturally, the diameters of the protrusion 4 and the post 7 are dimensioned to achieve the desired form of operation.

The invention's basic idea is that, if there is a collision with the post, the lower end of pipe 5, or, if a pipe is not used, of post 7, slips off protrusion 4, the force of the impact turning the pipe or part of the post inside the base against the inner

surface of the cone while the section of the post above the ground turns more or less around point 6. Thus, the damage caused by the collision will very probably be much less than the damage due to a collision with an essentially rigid post.

The invention's attachment of pipe 5 or the lower end of post 7 to protrusion 4 with the protrusion partly inside the lower end of the pipe/post, is easy and effective, as it results in a situation, in which no part of the base need be replaced after a collision, instead the initial situation is restored by turning pipe 5 or post 7 back to its original position, possibly by lifting it slightly.

If pipe 5 is made from plastic and the base cone is made from the same or a different plastic, it will often be possible to make a watertight joint with either a separate sealing ring or else making an absolutely watertight joint by welding the seam between the pipe and cone 2 shut. Plastic is a light and economical manufacturing material, so-called recycled plastic being eminently suitable, as, base 1 being practically invisible, there is no problem with the colour or precise composition of the end product. Suitable reinforcements can be made easily in the surface of the plastic cone, resulting in a construction of sufficient strength to withstand all normal situations.

A base according to the invention is easy and simple to install in its operating environment. The base is supported in a conventional manner on the bottom of a pit excavated to a suitable depth; the pit then being backfilled to the desired height, when the material placed on top of the upwardly narrowing structure will hold the base firmly in place.

It is obvious that a joint permitting the lower end of the pipe or post to turn inside conical surface 2 can be made in many other ways than by supporting it on protrusion 4 on the bottom. For example, and in particular, if it is desired that the post supported by the base will move in a particular path or similar, the lower end of pipe 5 or post 7 that penetrates the base can be secured to its surroundings, in this case mainly to the jacket surface of the base, with suitable retainers, which will flex or break if a sufficient force strikes the post above the base.

Figure 2 shows an example of the construction described above. It shows, from directly above, the lower end of pipe 5 surrounded by a collar or ring 9, which is secured to jacket surface 2 by three ties 10. Though the ties can be as many as desired, three is the minimum number. It is assumed that the ties are flexible, allowing them to stretch when the lower end of the pipe or post tries to turn to the side. Alternatively, ties 10 can break, if a sufficient impact or force strikes the post from the side.

It is clear that many other ways of holding the pipe-like piece in place can be found in various fields of technology, the invention not being in any way restricted to the above. One case worth mentioning is the use of cellular plastic to support pipe 5 or post 7 and as the flexible element, as its characteristics include returning to its initial shape prior to the collision with the post or pipe. This is shown by reference number 12 in Figure 1. In addition, cellular plastic's properties are beneficial to this embodiment, as cellular plastic does not absorb water and is suitably shock absorbing.

Figure 1 also shows diagrammatically, by reference number 11, a suitable opening, through which a cable, leads or other desired devices can be brought into the base, to carry out specific functions.

Figure 3 shows a diagram of a collision. Striking a rigid post usually results in the post bending with great force on top of the vehicle, causing at least material damage. A collision with a post equipped with a base according to the invention will cause the reaction shown in Figure 3, in which the post turns with the impact, causing much less damage than a collision with a traditional post.

Figure 4 shows an adaptation of a base according to the invention. In this embodiment, the base can be, for example, a concrete ring or similar, and thus no longer a cone. However, here too the post turns according to the basic idea of the invention and according to the principles described above. A protrusion 4 on the bottom of the base holds the lower end of pipe 5, or alternatively the post, in place. The upper part of the base ring has a retaining device 13, holding the pipe

or post more or less firmly in place, but nevertheless so that turning is possible.

The device can be supported, for example, on the edges of the ring, or on its inner surfaces, or in an otherwise suitable manner.

In a collision, the lower end of the pipe or post will slip off the protrusion, so that the section of post above ground can turn with the impact. This embodiment also incorporates a diagram of a cellular plastic cushion 12, to be used instead of, or with protrusion 4.

According to another alternative embodiment, the post can also be allowed to turn by attaching the pipe or post essentially rigidly to the bottom of the base, turning being permitted by a device, such as 13, in the top of the base. Thus, in a collision, device 13 will give way and permit the post to turn to a slant in line with the force of the impact.

The invention can be adapted in many ways while still remaining within both the inventive step (that the post turns as the result of a collision) and the scope of the protection of the accompanying Claims. For example, the shape of the base can vary greatly, while the principles stated above still apply to it. One alternative is to construct the base entirely from cellular plastic, the base narrowing upwards and having an essential central hole for the pipe or post, the flexibility of the material from which the base is made permitting the post to turn to a slant as described above. By selecting a suitable cellular plastic material, a sufficiently sturdy attachment can be created while still ensuring the desired flexibility.