SE541561C2

SE541561C2 - Replacable knock down post module

Info

Publication number: SE541561C2
Application number: SE1750974A
Authority: SE
Inventors: Lars Gunnar Strandberg
Original assignee: Skydd100 Ab
Priority date: 2017-08-08
Filing date: 2017-08-08
Publication date: 2019-10-29
Also published as: WO2019030295A4; EP3649294B1; SE1750974A1; ES2928139T3; EP3649294A1; WO2019030295A1; DK3649294T3

Abstract

The invention relates to a replaceable support module for posts in a traffic environment, said posts supporting a traffic sign, traffic signal or simply a barrier post, containing in essence two members, a lower and an upper part 10 and 20, with these two parts pressed together by a connecting rod 40. The support module could deflect somewhat while cornpressing springs 45,49, not inflicting any deformation of the post. Further deflection is developed as plastic deformation of the connecting rod 40 while a convex surface roll over a fiat surface in the lower and upper parts.if the post has been run down by traffic could the support module be quickly replaced with a new support module with a new connecting rod, while the deformed connecting rod is replaced with a straight connecting rod in the old support module to be used again.

Description

REPLACABLE KNOCK DOWN POST MODULE.

Background of the Invention The present invention relates to a replaceable knock down module used when mounting a vertically oriented post in a traffic environment, preferably a post supporting a traffic sign, a traffic light or simply a traffic barrier, in a prefabricated ground base element with a vertical mounting bore for said post.

More than 7000 posts supporting traffic signs need to be replaced yearly in a medium sized town like Stockholm with about 1 million inhabitants. The posts are typically run down by cars and heavy vehicles. The cost for replacing a post is not only restricted to a new post as such, but may also relate to replacement of the ground base element, typically buried 60-100 centimeter down into the ground. Conventionally is the ground base element made in concrete as a prefabricated standard element. In some urban areas with heavy traffic could one and the same signpost be run down up to 10-20 times per year.

Posts used as traffic barriers separating oncoming traffic from each other, or separating vehicles from pedestrians, have been used frequently, which in some cases also support multiple steel wires led between posts. These posts are more or less meant to be run over by cars, and also need frequent exchange of posts.

This problem area with posts needing replacement has been in focus over decades, and several different proposals have been presented and patented but not many of those has been put into regular use, as they may bring along other problems such as safety risks for pedestrians or drivers of the vehicles.

Prior Art Several prior art solutions involve usage of a spring member in the base of the signpost, but this design may cause severe risks when the signpost suddenly is released from the impacting vehicle and bounces back with considerable force and speed. One such solution is shown in Gebrauchmuster DE9301135 where a joint between a convex end surface of the pole and a concave surface on the base is kept together by a heavy spring arranged inside the pole, allowing the vertically oriented pole to deflect into a horizontal position where the spring is compressed and thus preloaded to a maximal extent. In US7377717 was issued as late as 2008 a further development of this kind of spring loaded mount, but using two spring-loaded wires and cooperating and complimentary notches and ridges in the convex and concave surfaces. In US7726056 was issued 2 years later yet a patent with a heavyduty spring connecting the signpost pole with the base.

Other solutions involve a weak part that breaks upon impact, which may release the signpost into surrounding traffic and cause more injuries. One such solution is shown in DE29801441, having an intermediate cylindrical member mounted on a base member, with the weak point of the intermediate member located at a distance from the base member inside the signpost. Once broken the entire signpost will be thrown away into surrounding traffic. Yet another solution of this kind is shown in DE2319229 where the weak point is located in a coaxial insert between the lowermost part of the signpost pole and a base mounted lower pole.

Yet other solutions involve usage of a plastically deformable element in the end of the signpost, that deforms at any order of impact and may be replaced afterward. One such solution could be seen in FR2836166, but needs replacement of the deformable even if the impact force is low.

Summary of the Invention: The invention is related to an improved design for a replaceable knock down module that could reduce cost for replacing a post in a traffic environment that has been run over by vehicles, and do not have the disadvantages with prior art.

In following parts are details referred to as a lower or upper part, and this is in relation to a vertically mounted post, i.e. a lower part is closer to ground and an upper part closer to the sign at the end of the post. Also, length is referred to as an axial distance in the direction of the vertically mounted post, and diameter is related to a measurement in a horizontal plane intersecting the post orthogonally. Even if embodiments show a post for a traffic sign, said post may carry a traffic signal or simply be a barrier post between lanes in traffic.

According to the most general aspect is a replaceable knock down module used when mounting a vertically oriented post of a traffic sign in a prefabricated ground base element with a vertical mounting bore, Said knock down module comprising: a lower module member insert able into the vertical mounting bore of the ground base element and with an outer form complimentary with the inner form of the mounting bore allowing the lower module to be inserted into the bore, said lower module also incorporating an upper and upwardly facing surface aligned with the upper surface of the ground base element when the lower module is fully inserted into the bore; an upper module member insert able into the post of a traffic sign and with an outer form complimentary with the inner form of the post allowing the upper module to be inserted into the post, said upper module also incorporating a lower and downwardly facing surface in contact with the upper and upwardly facing surface of the lower module; a vertically oriented connecting member arranged in the center of both the upper and lower module members with an upper washer element preventing the connecting member from being withdrawn from the upper module member and with a lower washer element preventing the connecting member from being withdrawn from the lower module member; and wherein one of the upper and upwardly facing surface (21) or the lower and downwardly facing surface has a convex surface symmetrically around the connecting member, and the other upper or lower surface has a flat surface, allowing the convex surface to roll over the flat surface when post is deflected from its strict vertical orientation.

These general basic features enable the post to be deflected upon impact, such that a rolling motion is developed between the convex surface and the flat surface of the upper and lower module, with the point of contact between these surfaces changing as the post deflects further from the ordinary vertical position.

According to a preferred embodiment of the inventive replaceable knock down module is the connecting member also including a centrally located rod with a length exceeding that of the vertical length of the upper module member and preferably less than the total length of the upper and lower module member in an assembled state of said knock down module and with the upper and lower washer elements arranged on the upper and lower ends of said rod. The usage of this long rod in the connecting member enable a distribution of any plastic deformation that may occur when the long rod is exposed to axial stresses upon deflection of the post, without a short and stiff connection that easily may break upon deflection of the post.

According to another preferred embodiment of the inventive replaceable knock down module is the connecting member including also a compression spring arranged concentrically of said rod and located between the upper and lower washer members. This compression spring will provide a biasing force on the module keeping the post in the vertical position.

According to yet another preferred embodiment of the inventive replaceable knock down module is the rod of the connecting member including an upper locking nut engaging a threaded upper part of the rod and a lower locking nut engaging a threaded upper part of the rod. These end nuts will provide an adjustable clamping force keeping the lower and upper parts tightly together.

According to yet another preferred embodiment of the inventive replaceable knock down module is he the connecting member including a washer spring arranged concentrically of said rod and located between the lower locking nut and the lower washer member. This additional resilient washer spring could provide with a lower biasing force that could give in during touching impact from vehicles that only deflects the post some 10-20 degrees, which kind of impact often occurs at parking lots and similar places where vehicles travel in low speed and in restricted areas for maneuvering.

According to a preferred embodiment for low speed impact of the inventive replaceable knock down module is the lower module member including a lower chamber with an internal diameter leaving a distance between the internal surface of the lower chamber and the vertically oriented connecting member protruding axially downwardly in said lower chamber. This enable a certain smaller deflection of the post before the connecting rod starts to plastically deform the connecting rod.

According to a preferred embodiment of the inventive replaceable knock down module is the axial length of the lower module member running down into the bore of the ground base element, when fully mounted, exceeding 15 centimeters, and preferably in the range 15-40 centimeters. This allows a distribution of stress forces over a larger area when post deflects, avoiding any cracking or deformation of the ground base element, and thus enable that entire deformation is assumed in the knock down module only.

Likewise, in order to reduce local stress forces on the ground base element, according to a preferred embodiment of the inventive replaceable knock down module is the diameter of the upper and upwardly facing surface exceeding the diameter of the post and exceeds 10 centimeters and at least cover the upper end face of the ground base element.

In the inventive replaceable knock down module has preferably also the convex surface a spherical form with a constant radius over the entire convex surface. The spherical form gradually changes the contact point between the upper and lower module members as the post deflects.

In a preferred embodiment of the spherical form may the radius correspond to the radius of the post. However, other shapes of the spherical form may be used that results in this smooth change of contact point between the surfaces and a rolling motion between the lower and upper modules. The radius may for example be larger than the radius of the post, with a (half-) ball-like end member having a radius 2-5 times the radius of the post.

In a possible alternative of the inventive replaceable knock down module may the convex surface have a transition surface closest to the connecting rod being flat. This will reduce tendency to deflect post at very small impact forces, or when the sign and post is exposed to strong wind.

The connecting rod of the inventive replaceable knock down module preferably has a diameter less than 25% of the diameter of the post, preferably in the range 5-15 mm if the post has a diameter in the range of 50-100 mm, and said rod being made in one piece with threaded ends or preferably as a continuous threaded screw with a ductility allowing plastic deformation and elongation of the rod by as much as over 10% before breaking. Hence, a brittle rod breaking easily is not to be used, as the rod should be plastically deformed during post deflection when impact forces exceed a certain level, i.e. until the rod end meets the inner surface of the lower module member. Normal carbon steel qualities in threaded rods may thus be used.

These aspects of the invention are defined in attached claims, but the inventive replaceable knock down module may be modified in several ways beyond the embodiment disclosed in attached figures and described in more detail below.

List of Drawings In the following schematic drawings may same details not be numbered in additional figures.

Figure 1; Show a traffic sign mounted on a post and with the inventive support module; Figure 2; Show an embodiment of a standard ground base element typically used; Figure 3; Show the inventive support module in the initial mounting position; Figure 4; Show the inventive support module in a first order of deflection of the post; Figure 5; Show the inventive support module in a slight modification of that shown in figure 3, with a smaller part of the convex surface being flat; Figure 6; Show an alternative inventive support module with a larger diameter on the spherical part; Figure 7a; Show the standard cylindrical hole in the ground base in upper figure and the post in lower figure, with differing forms of the mounting hole in the ground base in upper row of figures 7b, 7c and 7d, with necessary adapters in lower part of figures.

Detailed Description of the Invention Figure 1 show a traffic sign 2 mounted on a post 2 and with the inventive support module 10,20 inserted into a ground base element 30, that is buried some 40-100 centimeters into the soil mass 50. The upper module member 10 is inserted into the lower end of the post and has a length L10, when fully mounted, exceeding 10 centimeters, and preferably in the range 10-40 centimeters. This allows a distribution of stress forces over a larger area of the post when post deflects, avoiding any cracking or deformation of the post, and thus enable that entire deformation is assumed in the knock down module only.

The lower module member 20 is inserted into a bore of the ground base element 30 and has a length L20of the lower module member running down into the bore of the ground base element, when fully mounted, exceeding 20 centimeters, and preferably in the range 20-40 centimeters. This allows a distribution of stress forces over a larger area when post deflects, avoiding any cracking or deformation of the ground base element, and thus enable that entire deformation is assumed in the knock down module only.

As the ground base elements typically are made in concrete, such concrete ground base elements are less resistant to tension forces (tending to expand the surrounding ground base element), while the post most often made in galvanized carbon steel, could withstand much higher order of tension forces and thus may the insertion length be shorter for the upper module member.

Figure 2 show the typical standardized prefabricated ground base element 30, with a bore 31 for mounting of a suitable post.

Now, even if circular post 1 predominantly are used, and with cylindrical bores 30 in the ground base element 30, other shaped of the post and cooperating bore may be used. Hollow posts with a triangular, rectangular, pentagonal of hexagonal cross section may also be used.

In Figure 3 is shown the inventive support module as such in the initial vertical mounting position. The support module contains two members, a lower and an upper part 10 and 20, with these two parts pressed together by a connecting member 40.

The lower module member 20 is insert able into the vertical mounting bore of the ground base element. The lower module member has an outer form complimentary with the inner form of the mounting bore allowing the lower module to be inserted into the bore. Said lower module also incorporating an upper and upwardly facing surface 21 aligned with the upper surface of the ground base element when the lower module is fully inserted into the bore.

The upper module member 10 is insert able into the hollow post of a traffic sign. The upper module has an outer form 12 complimentary with the inner form of the post allowing the upper module to be inserted into the hollow post. Said upper module also incorporating a lower and downwardly facing surface 11 in contact with the upper and upwardly facing surface 21 of the lower module.

Further, a vertically oriented connecting member 40 is arranged in the center of both the upper and lower module members 10 & 20 with an upper washer element 41 preventing the connecting member from being withdrawn from the upper module member and with a lower washer element 43 preventing the connecting member from being withdrawn from the lower module member. The lower washer member 43 also functions as a sliding washer that allows the washer to slide upon deformation of the connecting member until the outer periphery of the washer 43 meets the internal surface of the chamber CH.

Finally, the distinctive feature of the support module is that one of the upper and upwardly facing surface, in this embodiment 21, or the lower and downwardly facing surface, in this embodiment 11, has a convex surface CF symmetrically around the connecting member 40, and the other upper or lower surface has a flat surface FF, allowing the convex surface to roll over the flat surface when post 1 is deflected from its strict vertical orientation. Hence, the convex surface may be arranged on surface 21 and the flat surface on surface 11, opposite to the what is shown in figure 1.

As indicated may also a protective socket 19 be arranged around the area of rolling motion between the convex surface 11 / CF and the flat surface 21 / FF, preventing ingress of gravel etc that could counteract the intended rolling motion. Such a protective socket is made in a thin cylindrical shielding plate of a break-away type that collapses upon small order of deformation.

As could be seen in figure 3 is the upper module member 10 provided with a cylindrical guide surface 12 onto which the post could be guided until the end surface of the post comes into abutting contact with the shoulder 13. Further, in this starting position could also be seen that the lower end of the connecting rod is located at a clearance d to the inside of the chamber in the lower module member 20.

In Figure 4 is shown the inventive support module in a first order of deflection of the post, and the function of support module will be described in more detail with description of interaction between parts thereof. In this figure is shown an order of deflection of the post that may lie in a deflection angle a of about 10-20 degrees, depending on sizing of chamber CH and length of the connecting rod 40.

In this position has the end of the connecting rod come into abutting contact with the inner cylindrical wall surface of the chamber CH, and the support module has been deflected without any plastic deformation of the connecting rod 40. Instead has the washer spring 45 been compressed and the lower washer 43 has been pushed to the right in the figure, while the compression spring 49 has been bent. During the deflection range between the position shown in figure 3 and the position shown in figure 4, are only the springs 45 and 49 elastically deformed, and once the deflecting impact is withdrawn is the post recapturing the position of figure 3. The support module could thus absorb a moderate impact that may be inflicted upon the post from vehicles travelling at low speed, without any need for replacing the post or associated support module.

When the post 1 experience a larger deflection that that shown in figure 4 is a second phase activated where the connecting rod 40 starts to deform plastically, and thus keeps the deformed state also when the impact is withdrawn. During this deformation of the connecting rod 40 will the convex surface of upper module member 10 roll on the flat surface of the lower module 30, while further compressing the washer spring 45. The form of the surfaces will introduce a smoothly increasing axial force on the connecting rod 45, while being counteracted by the washer spring 45. This will proceed until the post lies parallel to the ground surface, but with the connecting rod still in place. The calibration of the connecting rod, i.e. choice of material and diameter of the rod, may easily be tested, and preferably could normal steel qualities be used that may withstand a extension of 10-12% before breaking.

In figure 5 is shown the inventive support module in a slight modification of that shown in figure 3, with a smaller part of the convex surface being flat. This flat end piece of the surface 11 may be only 2-5 mm wide, leaving most of the convex surface intact. The flat part of surface 11 may stabilize the ordinary vertical position of the post, avoiding deflection in heavy wind if the sign mounted on the post has a large impact surface.

In figure 6 is shown an alternative inventive support module with a larger diameter on the convex surface 11 / CF.

In figure 7a is shown the standard cylindrical hole 31 in the ground base 30 in upper figure and the post in lower figure 7a.

In figure 7b is shown a different mounting hole with square form in the ground base 30 in the upper figure, requiring an adapter as shown in lower figure 7b.

In figure 7c is shown a different mounting hole with hexagonal form in the ground base 30 in the upper figure, requiring an adapter as shown in lower figure 7c.

In figure 7d is shown a different mounting hole with a cross form in the ground base 30 in the upper figure, requiring an adapter as shown in lower figure 7d.

Hence, with adapters as suggested above, i.e. the lower row of figures 7a-7d, could the same inventive support module be used for different ground base elements, and for standard posts.

The invention may be modified in many ways without departing from the concept as shown in figures.

Claims

1. . A replaceable knock down module used when mounting a vertically oriented post (1) in a traffic environment, preferably a post supporting a traffic sign, a traffic light or simply a traffic barrier, in a prefabricated ground base element (30) with a vertical mounting bore (31) for said post, comprising: a lower module member (20) insert able into the vertical mounting bore (31) of the ground base element (30) and with an outer form complimentary with the inner form of the mounting bore allowing the lower module (20) to be inserted into the bore (31), said lower module also incorporating an upper and upwardly facing surface (21) aligned with the upper surface of the ground base element (30) when the lower module is fully inserted into the bore (31); an upper module member (10) insertable into the post of a traffic sign and with an outer form (12) complimentary with the inner form of the post allowing the upper module to be inserted into the post, said upper module also incorporating a lower and downwardly facing surface (11) in contact with the upper and upwardly facing surface (21) of the lower module; a vertically oriented connecting member (40) arranged in the center of both the upper and lower module members (10 & 20) with an upper washer element (41) preventing the connecting member from being withdrawn from the upper module member and with a lower washer element (43) preventing the connecting member from being withdrawn from the lower module member and; wherein: one of the upper and upwardly facing surface (21) or the lower and downwardly facing surface (11) has a convex surface (CF) symmetrically around the connecting member (40), and the other upper or lower surface has a flat surface (FF), allowing the convex surface to roll over the flat surface when post (1) is deflected from its strict vertical orientation;. characterized in that: the connecting member (40) includes a centrally located rod with a length exceeding that of the vertical length of the upper module member (10) and preferably less than the total length of the upper and lower module member (10+20) in an assembled state of said knock down module and with the upper and lower washer elements (41, 43) arranged on the upper and lower ends of said rod and a compression spring (49) arranged concentrically of said rod and located between the upper and lower washer members (41,43); and, the lower module member (20) includes a lower chamber (CH) with an internal diameter leaving a distance (d) between the internal surface of the lower chamber and the vertically oriented connecting member (40) protruding axially downwardly in said lower chamber.

2. A replaceable knock down module according to claim 1 characterized in that the rod of the connecting member (40) includes an upper locking nut (42) engaging a threaded upper part of the rod and a lower locking nut (44) engaging a threaded lower part of the rod.

3. A replaceable knock down module according to claim 2 characterized in that the connecting member (40) includes a washer spring (45) arranged concentrically of said rod and located between the lower locking nut (44) and the lower washer member (43).

4. A replaceable knock down module according to claim any of the previous claims characterized in that the axial length of the lower module member (20) running down into the bore (31) the ground base element when fully mounted, exceeds 15 centimeters, and preferably in the range 15-40 centimeters.

5. A replaceable knock down module according to claim 4 characterized in that the diameter of the upper and upwardly facing surface (21) exceeds the diameter of the post and exceeds 10 centimeter and at least cover the upper end face (32) of the ground base element (30).

6. A replaceable knock down module according to claim 1 characterized in that the convex surface (CF) has a spherical form with a constant radius over the entire convex surface.

7. A replaceable knock down module according to claim 6 characterized in that said constant radius correspond to the radius of the post.

8. A replaceable knock down module according to claim 7 characterized in that the convex surface (CF) has a transition surface (13) closest to the connecting rod (40) being flat.

9. A replaceable knock down module according to claim 1 characterized in that the rod of the connecting member (40) has a diameter less than 25% of the diameter of the post, preferably in the range 5-15 mm if the post has a diameter in the range of 50-100 mm, and said rod being made in one piece as a continuous threaded screw with a ductility allowing plastic deformation and elongation of the rod by as much as over 10% before breaking.

10. A replaceable knockdown down module according to any of the previous claims characterized in that said lower washer element (43) is a sliding washer with a diameter which less than the diameter of the internal surface of the lower chamber and which allows the washer to slide upon deformation of the connecting member until the outer periphery of the washer (43) meets the internal surface of the chamber CH.