Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
POST WITH DISCONNECTABLE PARTS FOR END TERMINAL
Document Type and Number:
WIPO Patent Application WO/2012/010310
Kind Code:
A2
Abstract:
The invention relates to a post for an end terminal for a safety barrier, the end terminal comprising at least one rail and a number of posts to support the rail or rails, wherein each post comprises an upper part and a lower part which upper and lower part are connected to each other in such a manner that the upper and lower part of the post disconnects under a predetermined load. This is achieved by providing at least one pin member in one of the parts of the post and at least one notch in the other part of the post wherein with the upper part and lower part of the post connected to each other at least one pin member is positioned in at least one notch.

More Like This:
Inventors:
SIRMAN, Steven, Charles (Group Intellectual Property Services, Wenckebachstraat 1, NL- 1951 JZ VELSEN-NOORD, NL)
BAYTON, Andrew (Group Intellectual Property Services, Wenckebachstraat 1, NL- 1951 JZ VELSEN-NOORD, NL)
Application Number:
EP2011/003660
Publication Date:
January 26, 2012
Filing Date:
July 21, 2011
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
TATA STEEL UK LIMITED (30 Millbank, London SW1P 4WY, GB)
SIRMAN, Steven, Charles (Group Intellectual Property Services, Wenckebachstraat 1, NL- 1951 JZ VELSEN-NOORD, NL)
BAYTON, Andrew (Group Intellectual Property Services, Wenckebachstraat 1, NL- 1951 JZ VELSEN-NOORD, NL)
International Classes:
E01F15/04; E01F15/14
Domestic Patent References:
WO1999032728A11999-07-01
Foreign References:
US20060038164A12006-02-23
US4838523A1989-06-13
Attorney, Agent or Firm:
BLAUW, Frans (Tata Steel Nederland Technology B.V, Tata Steel- Group IPSPO Box 10000, CA IJmuiden, NL-1970, NL)
Download PDF:
Claims:
CLAIMS

Post for an end terminal for a safety barrier, the end terminal comprising at least one rail and a number of posts to support the rail or rails, wherein the post comprises an upper part and a lower part of which the upper and lower parts are connected to each other such that these post parts disconnect under a predetermined load, characterised in that one of the parts of the post is provided with at least one pin member and the other part of the post with at least one notch wherein with the upper and lower parts of the posts connected to each other at least one pin member is positioned in at least one notch, therewith retaining the part provided with at least one notch in the member provided with at least one pin member, and wherein the parts of the posts disconnect at a predetermined load by deformation of the material adjacent a notch in which a pin member is positioned.

Post according to claim 1, characterised in that at least one notch is bound on opposite sides by a first portion and a second portion and between the first and second portion by an intermediate portion, wherein the first portion is longer than the second portion.

Post according to claim 2, characterised in that with the post assembled the second portion extends in a direction transverse to the corresponding pin member and has a length in a range from the sum of the length of the intermediate section and 0.1 times the width of the pin member to the sum of the length of the intermediate section and 2 times the width of the pin member.

Post according to claim 2 or 3, characterised in that the intermediate portion extends in a direction transverse to the corresponding pin member in a range from 0.5 - 3 times the width of the pin member, preferably from 1 - 2.5 times the width of the pin member.

5. Post according to one or more of claims 2-4, characterised in that the first portion extends beyond the pin member for at least 1.5 times the sum of the intermediate portion and the width of the pin member.

6. Post according to one or more of claims 1-5, characterised in that the part of the post provided with at least one pin member is a channel or tubular section wherein at least one pin member is positioned at the inside of the section.

7. Post according to one or more of claims 1-6, characterised in that a single pin member is provided extending from wall to wall across the channel or tubular section.

8. Post according to one or more of claims 1-7, characterised in that at least one pin member is positioned with the length axis thereof transverse to the length direction of the safety barrier.

9. Post according to claim 8, characterised in that part of the post provided with at least one notch is a channel section with two notches or a tubular section with a single notch.

10. Post according to one or more of claims 1-9, characterised in that the part of the post with at least one pin member is the lower part of the post.

11. Post according to claim 10, characterised in that the lower part of the post is at least partly entered into the ground.

12. End terminal for safety barrier comprising at least one rail and a number of posts according to one or more of claims 1 -1 1 to support at least one rail, characterised in that the rail comprises successive portions that are slideably connected to each other.

13. End terminal according to claim 12, characterised in that overlapping parts of the rail sections are provided with corresponding longitudinal slots with breakable bridges wherein the longitudinal slots are bolted to each other. 14. End terminal according to claim 12, characterised in that the last rail portion is provided with an end assembly at the free outer end of the rail.

Description:
POST WITH DISCONNECT ABLE PARTS FOR END TERMINAL

The invention relates to a post for an end terminal for a safety barrier, the end terminal comprising at least one rail and a number of posts to support the rail or rails, wherein the post comprises an upper part and a lower part which upper and lower part are connected to each other such that these post parts disconnect under a predetermined load.

The collision of a vehicle against a safety barrier will in most cases be sideward and the impact of the collision will be absorbed by the deformation of the barrier rail. Because of the length of the rail and the number of posts supporting the rail, the rail will remain tensioned and the vehicle will be deflected back to the road. At the end of the safety barrier this will be different since a head-on collision at this point is very well possible. Different solutions have been proposed for this problem including telescoping rail elements, an inclined end of the rail ending beneath ground level, breakable posts and disconnecting parts of a post.

In W09932728 a post for an end terminal is disclosed consisting of an upper and lower part, wherein the lower part is provided with a support for the upper part and wherein the parts of the post are connected by means of a breakable pin. On collision of a vehicle head-on against the end terminal one or more of the breakable pins of the successive post will break absorbing at least partly the impact of the vehicle.

These breakable pins are supposed to break at a predetermined load. However, in practice it has proven to be quite difficult to tune a breakable pin so that it will indeed break at said predetermined load and even more so to manufacture series of pins that will all break at said predetermined load.

It is an objective of the invention to provide a post for an end terminal that gives way at a predetermined load.

It is a further objective of the invention to provide a post comprising a connected upper and lower part that disconnect at a predetermined load.

It is another objective of the invention to provide connecting means between upper and lower part of the post that can easily and reliably be tuned such that upper and lower part of the post will disconnect at a predetermined load. It is still a further objective of the invention to provide an end terminal for a safety barrier comprising a number of posts, each post comprising an upper and lower part that will disconnect at a predetermined load.

One or more of these objectives are realised by providing a post for an end terminal for a safety barrier, the end terminal comprising at least one rail and a number of posts to support the rail or rails, wherein the post comprises an upper part and a lower part which upper and lower part are connected to each other such that these post parts disconnect at a predetermined load, wherein one of the parts of the post is provided with at least one pin member and the other part of the post with at least one notch and wherein with the upper and lower parts of the posts connected to each other at least one pin member is positioned in at least one notch.

With the notch and pin member connection according the invention the load at which the connection between the upper and lower part of the post is disconnected is not dependent on the breaking of the pin member but on the deformation of the material adjacent to the one or more notches. The advantage of this feature is that the load at which the upper and lower part of the posts should disconnect can be fine tuned to a certain predetermined load. Moreover, once the dimensions for post and notch or notches for a certain predetermined load at which the upper and lower part should disconnect are known, the upper and lower part of the posts can easily be manufactured in series. With the notch and pin member system according to the invention inevitable small production deviations will not result in a load at which the upper and lower part of the post disconnect which is outside a defined small range for said predetermined load. This will result in an increased safety for driver and passengers in the unluckily event of a head-on collision against an end terminal of a safety barrier.

The notch and pin member are designed such that with the upper and lower part of the post in connection the part provided with at least one notch is retained in the member provided with at least one pin member. This means that dependent on the construction with notches and pin members that to connect the upper and lower part of the post with each other that at least one pin member is to be mounted or inserted after the upper and lower part of the post are brought into the right position with respect to each other. This is to prevent that the upper and lower part may be disconnected in any other manner than by deformation of the material around or adjacent the notch or notches under the predetermined load.

In this description the terms notch and pin member are used in the singular as well as in the plural. If used in the singular this could mean that a post is provided with only one notch and one pin member, but also that the post is provided with more than one notch and or pin member and reference is made to only one notch and/or pin member thereof.

The term pin member used in the description will mean any protrusion extending from a wall of upper or lower part of the post or any member extending from wall to wall in upper or lower part of the post which is sufficiently rigid to serve as a load reactive member against which the material around a notch may deform under load.

According to a further aspect of the invention it is provided that at least one notch is bound on opposite sides by a first portion and a second portion and between the first and second portion by an intermediate portion, wherein the first portion is longer than the second portion. With this construction when the upper and lower part of the post disconnect under load the second portion is pulled over the pin member in the course of which at least the second portion and the intermediate portion are deformed. The deformation of the area around or adjacent to the notch defines the load at which the upper and lower part of the post disconnect.

The pin member can have various shapes seen in cross-section for instance round, square, rectangular or triangular with a rounded, straight or stepped contact surface with the second portion of the post defining the notch.

According to a further aspect of the invention it is provided that with an assembled post the second portion extends in a direction transverse to the corresponding pin member and has a length in a range from the sum of the length of the intermediate section and 0.1 times the width of the pin member to the sum of the length of the intermediate section and 2 times the width of the pin member. The width of the pin member is the dimension measured transverse to the pin member and transverse to the length direction of the post.

According to a further aspect of the invention it is provided that the intermediate portion extends in a direction transverse to the corresponding pin member in a range from 0.5 - 3 times the width of the pin member, preferably from 1 - 2.5 times the width of the pin member.

The dimensions of the intermediate portion and that of the second portion together define to a large extent the load at which the upper and lower part of the post disconnect. These dimensions are also dependent on the width and shape of the pin member, which however is chosen such that it will not break or deform under the predetermined load at which the upper and lower part of the post disconnect.

With a pin member with a triangular shape the first and second portion will be at a sharp angle which could mean that the intermediate portion is reduced to a line with a certain length, wherein the length represents the width of the intermediate member as defined above.

The first portion is positioned against part of post, if the notch is made in a separate member that is affixed to the post, and the second portion is at the free end. Also if the notch is made directly in a part of the post, the second portion is at free end. This means that also the dimension in a direction at a right angle to the length is of importance in the tuning of the predetermined load at which the parts of the post disconnect. Thickness of the material is another parameter.

According to a further aspect of the invention it is provided that the first portion extends beyond the pin member for at least 1.5 times the sum of the intermediate portion and the width of the pin member. The first portion should be sufficiently rigid resulting in that the deformation on impact is defined by the intermediate and second portion. Moreover, if the notch is made directly in the section of the upper part or lower part of the post, the first portion is defined by the dimensions of that section. The section should be rigid enough to function as part of a post and also to transfer the load to the sections that define the predetermined load at which the upper and lower part of the post disconnect.

According to a further aspect of the invention it is provided that the part of the post provided with at least one pin member is a channel or tubular section wherein at least one pin member is positioned at the inside of the section. Although constructions with pin members on the outside of the upper part or lower part of the post are possible, it will be easier to retain one part in the other part of the post with one or more pin member on the inside. The pin member or members might be pins with fixed ends on both sides or pins with a fixed end and a free end. The most uncomplicated embodiment is the one with a single pin member extending from wall to wall across the channel or tubular section. A pin member extending from wall to wall is the most practical solution since a pin member, for instance a bolt, can be used which is put through holes in opposite walls after positioning the upper and lower part of the post.

According to a further aspect of the invention the part of the post provided with at least one notch is a channel section or a tubular section with two notches. Although it is well possible to fix one or more separate notch members to a part of the post, for instance by welding, it is preferred to provide at least one notch directly in the upper or lower part of the post by removing part of the material of said upper or lower part.

According to a further aspect of the invention the at least one pin member is positioned with the length axis thereof transverse to the length direction of the safety barrier. This direction is transverse to the load on the post with a head-on collision against the end terminal and results in that with more than one notch the load can be distributed evenly over the notches.

Preferably the part of the post with the at least one pin member is the lower part of the post. The lower part of the post is at least partly entered into the ground and more preferably with the pin member below ground level.

According to a further aspect of the invention an end terminal for a safety barrier is provided comprising at least one rail and a number of posts as described above to support the at least one rail, wherein the rail comprises successive portions that are slideably connected to each other. To that end the overlapping parts of the rail sections are provided with corresponding longitudinal slots with breakable bridges wherein the longitudinal slots are bolted to each other. With said end terminal the impact of a head- on collision is absorbed by one or more successive posts disconnecting when the predetermined load is exceeded, the breaking of the bridges in the rail portions, as a result of which the rail portions will slide over each other, and deformation of the rail portions.

The last rail portion is provided with an end assembly at the free outer end of the rail to transfer the load of the impact to the end terminal. The invention is further elucidated and shown in the non-limitative examples shown in the drawing, wherein: fig. 1 shows schematically a perspective view of a safety barrier with an end terminal, fig. 2 shows schematically a perspective view of a post with disconnectable parts, and fig. 3 shows a section of the post according to fig.1.

In fig. 1 a safety barrier 1 is shown provided with an end terminal 2. The end terminal 2 comprises a number of posts 3, rail portions 4 and an end assembly 8 at the outer end. Safety barrier 1 comprises a rail 5 and posts 7 to support the rail of which for clarity's sake only one is shown in the drawing. The end terminal 2 if further provided with end assembly 8.

The post 3 according to fig. 2 has an upper part 9 and a lower part 10. The lower part 10 is a rectangular tubular section and the upper part 9 a U-shaped channel section. It will however be clear that also C-sections, channel sections or round tubular sections could have been used for one of the parts or for both the upper and lower part of post 3.

In the lower part 10 a pin member 1 1 is provided extending across the width of lower part 10. Preferably a pin is used extending on both sides through openings provided in the opposite walls of lower part 10. A bolt with nut would be a possible embodiment for the pin member.

Pin member 11 is positioned in a notch 12. Notch 12 is defined by a first portion 13 above notch 12, a second portion 14 below notch 12 and an intermediate portion 15 between first and second portion 13, 14. The upper first portion 13 is in fact the portion of the upper part 9 of post 3 above pin member 1 1. The lower second portion 14 is far shorter than first portion 13 and ends in this example below pin member 11.

In fig. 3 the boundaries between first portion 13, second portion 14 and intermediate portion 15 are indicated with broken lines. With the U-shaped section these portions 13, 14, 15 continue from side to side. Further the walls of the upper part 9 of the post lie against the walls of the lower part 10 of the post 3 or are positioned close to these walls. In this position and with pin member 1 1 mounted the upper part 9 is retained in lower part 10. Further various dimensions of the upper and lower part 9,10 of the post 3 are indicated with capitals. The thicknesses A, B are chosen within the normal range for posts for safety barriers which is 6 - 10 mm.

The successive widths C and D of the upper and lower part 9,10 are chosen such that the width of the upper part is less than the width of the lower part 10 in order to give the upper part 10 enough room to move when the predetermined load is exceeded and the upper and lower part 9, 10 of post 3 disconnect. This is necessary to solely define the load at which the upper and lower part 9, 10 disconnect by means of the portions 13, 14, 15 around notch 12.

The width or in this example the diameter of pin member 1 1 is chosen such that it will not deform under load let alone that it will break. Depending on the predetermined load the diameter could be anywhere in a range from 8 - 30 mm. In most cases a diameter of 16 mm of pin member 11 will be more than sufficient.

By changing the dimensions E, H, I of the portions 13, 14 the load at which these parts will deform can easily be fine tuned therewith setting within a narrow range the load at which the upper and lower part 9,10 will disconnect.

Dimension H, the width of the second portion 14, can be split up in a dimension E representing the width of intermediate portion 15 and extension G with respect to the width of intermediate portion 15.

Dimension D of first portion 15 should be such that no or only insignificant deformation in said part will occur.

The dimensions C, D, E, G, H, I relate to the side walls of the upper and lower part 9, 10 which side walls are positioned transverse to pin member 1 1. The other sides of the upper and lower part 9,10 are important for the rigidity of these parts but are not important to tune the post 3 to a specific load at which the upper and lower part 9,10 should disconnect.

The overlap J of the upper and lower part 9,10 is of less importance but should be chosen in combination with C and D such that enough room is available to have the upper part 9 pulled out of the lower part 10 when the upper and lower part 9,10 disconnect when the predetermined load is exceeded.