WO2017176129A1 - Système de retenue et de libération dépendant de la force - Google Patents

Système de retenue et de libération dépendant de la force Download PDF

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Publication number
WO2017176129A1
WO2017176129A1 PCT/NZ2017/050040 NZ2017050040W WO2017176129A1 WO 2017176129 A1 WO2017176129 A1 WO 2017176129A1 NZ 2017050040 W NZ2017050040 W NZ 2017050040W WO 2017176129 A1 WO2017176129 A1 WO 2017176129A1
Authority
WO
WIPO (PCT)
Prior art keywords
washer
fastener
post
release system
aperture
Prior art date
Application number
PCT/NZ2017/050040
Other languages
English (en)
Inventor
Christopher James Allington
Andrew Karl DIEHL
Andrew SARRATT
Emerson RYDER
Ken READMAN
Nathan King
Original Assignee
Holmes Solutions Limited Partnership
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Holmes Solutions Limited Partnership filed Critical Holmes Solutions Limited Partnership
Publication of WO2017176129A1 publication Critical patent/WO2017176129A1/fr

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01F—ADDITIONAL WORK, SUCH AS EQUIPPING ROADS OR THE CONSTRUCTION OF PLATFORMS, HELICOPTER LANDING STAGES, SIGNS, SNOW FENCES, OR THE LIKE
    • E01F15/00—Safety arrangements for slowing, redirecting or stopping errant vehicles, e.g. guard posts or bollards; Arrangements for reducing damage to roadside structures due to vehicular impact
    • E01F15/02—Continuous barriers extending along roads or between traffic lanes
    • E01F15/04—Continuous barriers extending along roads or between traffic lanes essentially made of longitudinal beams or rigid strips supported above ground at spaced points
    • E01F15/0407—Metal rails
    • E01F15/0423—Details of rails
    • E—FIXED CONSTRUCTIONS
    • E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
    • E01F—ADDITIONAL WORK, SUCH AS EQUIPPING ROADS OR THE CONSTRUCTION OF PLATFORMS, HELICOPTER LANDING STAGES, SIGNS, SNOW FENCES, OR THE LIKE
    • E01F15/00—Safety arrangements for slowing, redirecting or stopping errant vehicles, e.g. guard posts or bollards; Arrangements for reducing damage to roadside structures due to vehicular impact
    • E01F15/02—Continuous barriers extending along roads or between traffic lanes
    • E01F15/04—Continuous barriers extending along roads or between traffic lanes essentially made of longitudinal beams or rigid strips supported above ground at spaced points
    • E01F15/0461—Supports, e.g. posts
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
    • F16B31/00—Screwed connections specially modified in view of tensile load; Break-bolts
    • F16B31/02—Screwed connections specially modified in view of tensile load; Break-bolts for indicating the attainment of a particular tensile load or limiting tensile load
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
    • F16B31/00—Screwed connections specially modified in view of tensile load; Break-bolts
    • F16B31/02—Screwed connections specially modified in view of tensile load; Break-bolts for indicating the attainment of a particular tensile load or limiting tensile load
    • F16B31/021—Screwed connections specially modified in view of tensile load; Break-bolts for indicating the attainment of a particular tensile load or limiting tensile load by means of a frangible part
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16B—DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING
    • F16B43/00—Washers or equivalent devices; Other devices for supporting bolt-heads or nuts

Definitions

  • Described herein is a force dependent retention and release system. More specifically, a system is described that links members together in a releasable manner dependent on an applied force via at least one tuneable retention means.
  • Force dependent retention and release systems may be used in a variety of applications such as signs, barriers, terminal ends of barriers, lifeline protection systems and so on.
  • a barrier system the members being an elongated longitudinal beam element that is typically located in a near parallel orientation with the ground and a post or posts that support the beam at a defined height and a retention means between the beam and posts.
  • This application should not be seen as limiting as many other applications are also possible as defined later in this specification.
  • the posts in a barrier system may be located at discrete distances along the length of the longitudinal beam. Most commonly, the posts are installed directly into the soil but equally the posts can be installed onto the surface of a more rigid medium (concrete or asphaltic-concrete).
  • a first connection is formed at the intersection between the post and the longitudinal beam and a second connection is located between the ground, or more rigid medium, and post. This first connection is required to provide support for the longitudinal beam in most circumstances but allow the longitudinal beam to separate from the posts in a controlled and repeatable manner when impacted by an errant vehicle.
  • the second connection is required to give stability to the post during normal retention and to react in a
  • a force dependent retention and release system may be used.
  • a retention system that releases upon a controlled displacement may also be used.
  • the system When installed as a roadside barrier the system is required to have sufficient strength and stiffness to be able to be installed and to remain rigidly in place under a variety of weather conditions.
  • the posts and connection detail must provide sufficient vertical support to the longitudinal beam to maintain its height relative the ground.
  • the system must also be able to withstand variations in temperature whereby the longitudinal beam (elongated tension element) can expand during hot temperatures and contract during colder weather, resulting in a longitudinal movement in the rail .
  • the strength and stiffness of the posts and the connection detail between the posts and the longitudinal beam must be able to accommodate this lateral (longitudinal along the length of the barrier) movement.
  • connection detail must have sufficient tolerance for vertical and horizontal misalignment of the connection detail to allow the posts to be joined to the longitudinal beam. For a conventional installation this may require up to ⁇ 25 mm in all directions.
  • the connection detail must also allow for angular misalignment of the connection point.
  • the primary purpose of the system as a roadside barrier is to protect the occupants of the vehicle from a roadside hazard and to protect other road users from the vehicle should it become errant.
  • To operate as desired it is required to contain and then redirect an errant vehicle when impacting the barrier.
  • an errant vehicle impacts the barrier it can be a violent and dynamic event resulting in damage to both the barrier and the vehicle.
  • the design of the barrier system can accommodate this violent impact and function as intended without causing harm to the vehicle occupants or other road users.
  • the longitudinal beam element is typically manufactured from a series of shorter length sections that are joined at regular intervals to form the full length of the barrier.
  • each length of longitudinal beam is up to 4 m long although longer segments may be used.
  • Most commonly the location of the joins in the longitudinal beam (often called a splice joint) are weaker or have higher stresses than the other sections of the longitudinal beam and if failure of the longitudinal beam is observed it commonly occurs at these locations.
  • the location of the joints is typically located at a post location. Therefore it is important to ensure that the connection between the longitudinal beam and the post limits any additional stresses placed into the longitudinal beam so as to limit the potential for failure at this location.
  • the longitudinal beam is required to deflect backwards by the errant vehicle. This backward motion of the longitudinal beam forces the posts which are attached to the longitudinal beam to also rotate backward. As the posts hinge backwards the height of the connection with the longitudinal beam above the ground level will reduce, due to the geometry of the motion. As the height of the connection with the longitudinal beam drops it will force the longitudinal beam to drop as well.
  • the impacting vehicle has the potential to override the barrier causing a hazard to the vehicle occupants and other road users. It is therefore critically important to limit the potential for downward motion of the longitudinal beam during an impact.
  • the downward motion of the longitudinal beam can be limited in a variety of manners:
  • the base of the post can move backwards in a similar manner to the top.
  • connection detail used to join the longitudinal beam and the posts can be designed so as to allow the two components to separate when impacted (see Figure 3). This allows the longitudinal beam to move upward relative to the post as it rotates backwards. This method has a considerable number of advantages if it is controlled correctly but this is very difficult to achieve.
  • US 8,353,499 describes a system using a vertical slot in the front face of a U-channel which is used to form the connection between the longitudinal beam and the post (see Figure 4 for a drawing of this design).
  • the slot allows the connection with the longitudinal beam to move upward relative to the post as the post rotates backwards.
  • At the top of the slot there is material bridging the top of the slot.
  • the fastener used in the connection reaches the top of the slot it is forced to fracture through this bridge in order to separate the longitudinal beam from the post.
  • the force required to achieve this fracture must be carefully controlled; if the force is too little then the longitudinal beam can separate early, if the force is too high then the longitudinal beam will stay attached too long and be dragged downward as the post rotates backward.
  • a further drawback of this system is that there may be a fine tolerance for the degree of fastener tightening. Too loose and the parts may detach prematurely. Too tight and the rail sliding movement may be impacted potentially causing the rail to be drawn down with the post due to the additional friction or clamping force created between the post and the beam.
  • this system allows for vertical movement between the post and the longitudinal beam and it creates a vertical release of the connection, however it does not allow the post to separate from the longitudinal beam in any other manner or direction of loading and therefore does not address the issues of releasing when the force perpendicular to the face of the post is sufficiently large, releasing due to twisting of the post, or the beam moving laterally or downwards.
  • the system is only described for use with U-shaped posts and is very specific to the properties of the post. Due to this limitation, the system cannot be installed with a longitudinal beam on both sides of the post (back-to-back or median installation). The system is also difficult to install due to the dimensions of the bridge at the top of the slot. This bridge is required to be small to limit the strength to ensure release occurs, and therefore because it is small it is prone to being damaged when installed into the ground, particularly since the majority of the posts are driven into the ground by being pounded using a falling weight onto the top surface. Any damage to this bridge can critically alter the manner in which the release mechanism occurs.
  • US 7,878,486 describes a system operated by using a smaller diameter fastener than intended for the size slot in the longitudinal beam element such that the head of the fastener can move directly through the slot in the longitudinal beam.
  • Figure 5 illustrates this art design.
  • a deformable washer is placed under the head of the fastener to prevent the fastener from falling through the slot.
  • a series of cup shaped washers are then installed between the longitudinal beam and the posts to provide the required seating between the post and the longitudinal beam.
  • a tension load is placed onto the fastener.
  • the tension load reaches the desired level (defined by the properties of the deformable washer) the edges of the washer deform and allow the longitudinal beam to separate from the post by the fastener pulling directly through the longitudinal beam element.
  • This system has no vertical tolerance. As the posts rotate backwards, the longitudinal beam is forced to travel down with the posts until such time that the tension force on the fastener exceeds the capacity of the washer. This form of release is prone to error and has the potential to drag the longitudinal beam downward if the properties of the washer are inconsistent or the placement of the washer is varied. By way of example, if the washer is located towards the middle of the slot it is apparent that it is required to deform less (to a lower force) than if the washer is located at either end of the slot where additional material is required to be deformed (thereby requiring a higher force). Additionally, if the fastener is installed to the edge of the slot in the beam, then the head of the faster is allowed to overlap with the material in the front face of the beam. In this configuration the washer cannot deform as it is constrained between the head of the fastener and the beam, rendering the unsuitable for use.
  • US 8,960,647 and US 9,217,230 operate by use of a deformable tab system formed integrally in the post.
  • the tab is designed to hinge away from the post as the post rotates backwards, with the hinge formed at the base of the tab (see Figure 6 for an illustration of this art design).
  • the top of the tab is connected to the post with a series of shear tabs that are designed to fracture under a predefined tension load and allow the tab to rotate.
  • the hinges at the bottom of the tab are also designed to fracture allowing the tab to break free from the post and allowing the longitudinal beam to separate from the post.
  • a key benefit of the system is described as being the simplicity of the connection. It does not require any additional components and can be formed with conventional fasteners. However, obtaining the correct performance of the system is difficult as there is insufficient difference between the force imparted on the tabs when holding the tab into the post under normal conditions and the forces which the tab must break under during an impact from a vehicle. Experience has shown that this can be difficult to achieve with insufficient tolerance between the forces obtained during an installation and those during an impact. Key issues with installations include the ability of the tabs to provide sufficient strength in a direction perpendicular to the post when the longitudinal beam is required to be installed around a convex curved where a high tension force perpendicular to the face of the post can be generated.
  • US2015/0014617 describes a system that operates by connecting the longitudinal beam to the post via a slider system, a drawing of this design illustrated in Figure 7.
  • This slider fits around the post and is relatively free to move up and down the front face of the post. As the posts rotate backwards the slider moves up the face of the posts and ultimately comes free from the top of the post.
  • a series of tabs are included on the face of the posts. These tabs interfere with the fastener used to connect the longitudinal beam to the post to provide some resistance to vertical movement.
  • a key issue with the system described in the '617 application is that the sliders are required to be inserted over the top of the posts and then are required to release from the top of the posts. Any damage that occurs to the top of the posts during the installation of the posts into substrate can prevent the sliders from being installed. Likewise, if the top of the posts are damaged during an impact then the sliders may not release in a consistent manner (or release at all) and result in the longitudinal beam being dragged downward with the posts. Additionally, if the fastener is not tightened to the full extent of the thread then it will not interfere fully with the tabs and will alter the release force of the system,
  • art force dependent releasable retention systems may have drawbacks such as bespoke parts, difficult installation and lack of tuneability. It would therefore be useful to address at least some of the art drawbacks or at least provide the public with a choice.
  • the retention means may be at least one deformable washer.
  • the deformable washer may be designed to transfer a load force from a first member via a fastener to a second member, the washer extending around the fastener and having a first face that bears on the fastener or a part thereof (or forms part of the fastener) and an opposing face that at least partly bears on a part of the first and/or second member.
  • the washer is designed so that, in the event of an imposed force of sufficient magnitude or an imposed displacement of a sufficient magnitude, on one or both members, the washer at least partly deforms allowing the members to separate.
  • a force dependent retention and release system comprising at least one first member and at least one second member, the members being indirectly linked via at least one fastener and at least one washer wherein the at least one washer comprises:
  • At least one deformable region extending at least partly about the aperture that at least partially bears on at least a part of the at least one fastener and an opposing face that bears on at least part of the first or second member; and, in the event of an applied force or a displacement being applied on either member or the fastener of sufficient magnitude, at least part of the at least one deformable region of the at least one washer deforms to an extent that the indirect link ceases to provide indirect attachment between the members, thereby releasing or loosening the connection between the members.
  • At least one deformable region extending at least partly about the aperture that at least partially bears on at least a part of the at least one fastener and an opposing face that bears on at least part of the first member;
  • At least part of the at least one deformable region of the at least one washer deforms to an extent that the indirect link ceases to provide indirect attachment of the first member and fastener, thereby releasing or loosening the connection between the first member and at least one fastener.
  • At least one washer for use in a force dependent retention and release system comprising:
  • At least one aperture that is sufficiently large to receive at least one fastener therethrough; and at least one deformable region extending at least partly about the aperture that is sized to at least partially bear on either or both of at least a part of the at least one fastener and at least part of a first member;
  • At least part of the at least one deformable region of the at least one washer deforms to an extent that the bearing face or faces are substantially removed.
  • a fifth aspect there is provided a method of arresting or re-directing the path of movement of an object by the step of installing a force dependent retention and release system substantially as described above.
  • the system may also minimise stress points on the member or members ensuring that the member or members do not fail in an unpredictable way in the event of an impact;
  • the system can translate one form of motion or force vector which doesn't apply a sufficient force or displacement to the washer to cause deformation into a second force vector or motion which does apply a force or displacement of sufficient strength to deform a region on the washer. Equally, the system can be constructed to undertake the opposite, thereby changing the motion or applied force so as to reduce the deformable load applied to the washer.
  • Figure 1 illustrates a schematic diagram of a first impact action
  • Figure 2 illustrates a schematic diagram of a second impact action
  • Figure 3 illustrates a schematic diagram of a third impact action
  • Figure 4 illustrates a prior art design
  • FIG. 5 illustrates an alternative prior art design
  • Figure 6 illustrates a further alternative prior art design
  • Figure 7 illustrates a further alternative prior art design
  • Figure 8 illustrates embodiments of washer shapes
  • Figure 9 illustrates alternative connection details in a post (shaded/dotted areas being the deformable washer).
  • Figure 10 illustrates a tab at top and bottom of slot embodiment to prevent overlap of the deformable washer with post material when at either end of the slot;
  • Figure 11 illustrates side views of an assembled post and beam illustrating the prying action resulting on a bolt with and without an upper tab (beak);
  • Figure 12 illustrates an image showing the post detail and aperture with an upper tab including a crease to form a protruding beak
  • Figure 13 illustrates the relative movement of a longitudinal beam and posts upstream and downstream of an impact
  • Figure 14 illustrates alternative views of the relative movement of a longitudinal beam and posts
  • Figure 15 illustrates side views of examples of flat and cupped washer shapes
  • Figure 16 illustrates an exploded view showing an example of use of a conventional nut and bolt
  • Figure 17 illustrates an embodiment of an installation with upper tab (beak) detail on the post providing a prying action on bolt to assist with release forces;
  • Figure 18 illustrates an alternative view of the typical installation embodiment of Figure 17
  • Figure 19 illustrates an image from a first side of a post and beam after separation and deformation of the washer caused by post rotation and twisting during impact
  • Figure 20 illustrates an image from the opposing side of a post and beam after separation a nd
  • Figure 21 illustrates a further different view of a post and beam after separation and deformation of the washer caused by post rotation and twisting during impact.
  • Figure 22 illustrates a post and beam located at a distance from the impact zine illustrating the
  • deformable washer still retaining the post and beam together but where the beam has moved upward to the top of the post and begun to deform.
  • the retention means may be at least one deformable washer.
  • the deformable washer may be designed to transfer a load force from a first member via a fastener to a second member, the washer extending around the fastener and having a first face that bears on the fastener or a part thereof (or forms part of the fastener) and an opposing face that at least partly bears on a part of the first and/or second member.
  • the washer is designed so that, in the event of a force of sufficient magnitude, on one or both members, the washer at least partly deforms allowing the members to separate.
  • the term 'about' or 'approximately' and grammatical variations thereof mean a quantity, level, degree, value, number, frequency, percentage, dimension, size, amount, weight or length that varies by as much as 30, 25, 20, 15, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1% to a reference quantity, level, degree, value, number, frequency, percentage, dimension, size, amount, weight or length.
  • substantially' or grammatical variations thereof refers to at least about 50%, for example 75%, 85%, 95% or 98%.
  • 'barrier', 'guardrail' and 'longitudinal beam' and grammatical variations thereof as used herein refers to the complete assembly being the longitudinal beam or beams, a post or posts, at least one fastener or fasteners, at least one washer and/or at least one integrated washer and fastener.
  • washer' and grammatical variations thereof as used herein refers to a plate with an aperture, the aperture opening defining an inside edge and an outside perimeter defining an outside edge.
  • the term 'fastener' and grammatical variations thereof as used herein refers to a mechanical linking means that may incorporate the washer as a separate part or the washer may be an integral part of the fastener.
  • the fastener may be a nut and bolt with the washer separately fitted over the bolt shaft.
  • the washer may form the bolt head or the nut or be integral to the shaft of the bolt and hence is integral to the fastener design.
  • Reference below to a fastener and washer incorporates both separate and integral designs and reference to one embodiment should not be seen as excluding the other embodiment.
  • W-beam' and grammatical variations thereof as used herein refers to a W-shape cross-section beam however, unless otherwise noted, reference to a W-beam should not be seen as limiting as other shapes of longitudinal beam, cables, or other elements may also be used, examples including box beams, U-channel beams and Thrie beams.
  • the term 'member' or grammatical variations thereof may be a post or beam other longitudinal part or material and may also be a substrate such as a ground surface or planar building surface for example. Reference to a post, beam or substrate such as the ground should not seen as limiting and, as may be appreciated, one may be substituted for the other.
  • a force dependent retention and release system comprising at least one first member and at least one second member, the members being indirectly linked via at least one fastener and at least one washer wherein the at least one washer comprises:
  • At least one deformable region extending at least partly about the aperture that at least partially bears on at least a part of the at least one fastener and an opposing face that bears on at least part of the first or second member;
  • At least part of the at least one deformable region of the at least one washer deforms to an extent that the indirect link ceases to provide indirect attachment between the members, thereby releasing or loosening the connection between the members.
  • At least one deformable region extending at least partly about the aperture that at least partially bears on at least a part of the at least one fastener and an opposing face that bears on at least part of the first member;
  • At least part of the at least one deformable region of the at least one washer deforms to an extent that the indirect link ceases to provide indirect attachment of the first member and fastener, thereby releasing or loosening the connection between the first member and at least one fastener.
  • At least one washer for use in a force dependent retention and release system comprising:
  • At least one aperture that is sufficiently large to receive at least one fastener therethrough; and at least one deformable region extending at least partly about the aperture that is sized to at least partially bear on either or both of at least a part of the at least one fastener and at least part of a first member;
  • At least part of the at least one deformable region of the at least one washer deforms to an extent that the bearing face or faces are substantially removed.
  • a fifth aspect there is provided a method of arresting or re-directing the path of movement of an object by the step of installing a force dependent retention and release system substantially as described above.
  • the first or second member load may be transferred from the fastener to the alternate member solely through the one or more deformable regions of the at least one washer.
  • deformable regions' or grammatical variations thereof refer to a region of the washer that is structurally weaker or of lower stiffness relative to another part of the washer.
  • the deformable region may be characterised by having at least one of:
  • variable material treatments and/or
  • Deformation of the at least one region may be primarily or exclusively plastic deformation although at least some elastic deformation may also occur.
  • the washer may be an important part of the overall system performance.
  • the properties of this washer may be altered to tune the performance of the washer in order to achieve the desired behaviour of the system.
  • Key variables that may for example be altered on the washer include material properties, thickness, number of cut-outs, size and shape of cut-outs, location of cut-outs, dimensions relative to the detail in the post, profile of the washer (cupped or flat), symmetry of the washer (both lateral and vertical), shape of the washer (square, round, rectangle, etc). Accordingly the performance of the washer is very tuneable for the desired outcome.
  • the washer may have a circular or semi-circular shape.
  • the use of a circular washer may ensure a consistent performance independent of the orientation of the washer, assuming consistent behaviour is desired. This makes for an easier installation.
  • other shapes and details may be used for the washer that alters the release load or deflection of the system when loaded in different directions or orientations. This can be used to optimise the performance of the system for specific applications.
  • the washer may be manufactured as a flat surface or it may be cupped so that it fits at least partially into an aperture in the first or second member. By varying the cupping of the washer, the degree of clamping friction formed between the washer and the member may be altered. Changing the clamping friction may help tune the force required to move a member relative to the alternate member in the plane of the clamped interface.
  • deformation of the deformable region may be tuned or tailored via many factors. Tailoring (or tuning) of the force needed to cause deformation may be useful for example to ensure a controlled separation at the desired load or displacement.
  • the system may also be tuned to provide different performances under different types of loads or movements. Further, the system may be tuned for different loads and movements in different directions. This degree of tuning and the various ways this can be achieved may be significant value as it allows considerable system versatility.
  • the washer may in one embodiment link the members with all linking forces transferred through a single member wall although this is not essential .
  • This single member wall may be the wall closest to the alternate member - herein referred to as the front face.
  • the washer may have a width greater than that of the widest part of the fastener, so that the fastener can move unobstructed through the member aperture upon the desired amount of deformation of the washer. Typically this might be the widest part of a nut used in conjunction with a bolt.
  • the at least one deformable region extending at least partly about the aperture at least partially bears on either side or both sides of at least a part of the at least one fastener and an opposing face that bears on at least part of the first or second member.
  • the washer may be sized to ensure it bears on the internal edge of the member and thereby prevent this lateral movement.
  • the shape of the member or the dimension of the washer may be modified accordingly.
  • Deformation as noted above results in the indirect connection ceasing or loosening. Ceasing or loosening may be a result of the washer and fastener(s) being drawn through either the first or second member. Alternatively, ceasing may be a result of the washer detaching from the fastener which in turn allows the members to detach. Equally, it may result in the fastener separating if a deformable region is located within the fastener itself. In more detail, in a separation event, the at least one fastener may be drawn out of a member, the deformed washer and fastener remaining attached to one member and released from the alternate member.
  • the fastener may be drawn out of the washer with a member attached in the event of an impact, the washer remaining located behind the wall of the member.
  • washer deformation may have the equivalent effect of bolt head removal or nut removal using a bolt and nut fastener as an example.
  • one member may have an aperture through which the fastener passes.
  • the aperture may be shaped in various ways to suit the desired end design parameters. Reference is made herein to a single aperture however multi-aperture applications may also be possible and reference to a single aperture should not be seen as limiting.
  • the term 'aperture' refers to a closed hole such as a round shaped hole but may also incorporate part openings or holes, one example being a U-shaped cut-out.
  • the aperture may have an elongated opening allowing the fastener to move to a predetermined extent in the direction of the elongation before deformation forces are applied to the washer.
  • Vertical movement allowance may be useful to extend the time and lateral deformation that the members remain engaged and therefore optimise the extent that the at least one of the members e.g. in a barrier embodiment, a longitudinal beam, that remains at a desired height above a surface or object (e.g. a road) before being drawn down or released by member rotation caused by an force of sufficient magnitude/impact.
  • the fastener may be installed at a low point (at or about the bottom of the slot). During an impact/imposed force, one member may be required to rotate backwards e.g.
  • the fastener and the deformable washer used to connect the second member (a beam for example) to the first member may move up the aperture until they impact the top of the aperture. If during this motion a force vector placed on the connection is sufficient, the capacity of the washer will be overcome and the deformable region(s) of the washer will deform thereby allowing the fastener to pull free of the member(s).
  • the force or motion applied to the member or fastener may result in the fastener interacting with the member in such a way as to cause the deformable washer to deform.
  • the shape of the top of the member aperture may be formed in any number of ways to control the behaviour of the system.
  • the shape may have a flat or outward radius end allowing the fastener to reach the end of the detail such that the material on the end of the washer may overlap with material on the front face of the member.
  • the fastener may then rotate relative to the face of the first member (e.g. a post) due to the moment couple created from the offset between the thickness of the second member (e.g. a longitudinal beam) and the thickness of the post.
  • the deformable region(s) of the washer will deform and allow the fastener to separate from the first member thereby separating the second member from the first member.
  • the deformation that occurs in this embodiment is the interaction of the fastener and the member translating a motion or force from a motion or force that does not deform the washer into one that causes it to deform.
  • the top of the member example above may for example transfer vertical translation of the washer into rotation and prying movement. This may be an effective way to tune the system for example to delay release or introduce a degree of hysteresis into the system.
  • the system can be constructed to undertake the opposite effect, thereby changing the motion or applied force so as to reduce the deformable load applied to the washer.
  • the alternative shape may limit the potential overlap between the washer and the material in the front face of the first member at the top of the aperture and therefore require a lesser force to pry out.
  • alternative shapes may comprise: inward radius or serpentine shapes; tabs; and shaped pathways.
  • the aperture shape may also be formed so as to alter the deformation characteristics of the aperture.
  • the aperture may be a T-shaped, X-shaped, wedged shape, key hole, or L-shaped hole and the aperture may therefore have regions where the washer can more easily be pulled through the aperture, for example about the intersection of the L, T or X shape or about regions where the resistance is higher.
  • Shaped aperture may also allow control of the relative motion of two members by the fastener following the shape of the aperture path, e.g. upward and then left.
  • the first member may also have an aperture sized to allow at least one horizontal plane or lateral movement. This may be useful for example to allow for expansion and contraction of the parts caused by high or low temperatures. Lateral movement allowance may also be important to address for example ribbon tension in a second member, e.g. a longitudinal beam, in the event of an impact. Ribbon tension refers to the tension forces imposed on a beam causing the beam to extend and deflect.
  • Allowing for some lateral movement of the fastener may alter the ribbon tension dynamics minimising the risk of beam failure or rupture whilst also addressing any rotation and/or shear forces imposed on the fastener as the first member or members rotate and move with the second member/beam deflection.
  • the system in the even of a force of sufficient magnitude on the system, the system is required to deflect backwards.
  • This backward motion places the second member e.g. .a longitudinal beam into tension due to the increase in length required to support the backward motion.
  • An effect of this motion is that the second member/longitudinal beam may be forced to move towards the point of impact from either side, causing a relative force vector and/or relative lateral movement between the first members and the second member.
  • this may place a relative movement (left to right) on the posts upstream of the point of impact and a relative movement of right to left on the downstream posts.
  • the opposite relative movement would occur in the case of an impact from the right hand direction.
  • this relative movement may be constrained by the washer bearing on the internal edges of the first member/post.
  • this lateral movement may be allowed to occur.
  • the use of a non-symmetric first member/post or non-symmetric apertures or aperture locations may allow movement in one direction only as the washer has no surface to bear against in the other direction.
  • the bottom of the first member aperture may be formed so that it limits the downward motion of the fastener. This may be achieved with a radius or a flat (square) bottom.
  • Using this form of aperture when the fastener is at the bottom of the aperture allows the washer to overlap the front face of the first member and provides additional resistance to pull-out force in the direction perpendicular to the face of the first member and to pull-out forces associated with twisting of the first member.
  • the bottom of the aperture may be formed with a section of the front face of the first member folded inward which therefore prevents the bottom of the washer from overlapping with the front face of the first member and ensure that only the side of the washer engages with the first member. In this orientation, the fastener may be suspended above the bottom of the aperture by the washer being supported by a folded element.
  • first member may be used in the system described above given that the design is not reliant on the member sides and member rear (the first member/post side opposing the second member/beam).
  • the first member may be of any geometric shape, provided they have a surface that mates to the back of the second member to allow the connection to be formed. This surface may have a sufficient width to allow the connection detail to be formed in the first member.
  • the first members may have the cross sectional shape of an I-beam, C channel, boxed section, U post, Z post, or ⁇ post.
  • other first member shapes are also possible, the shape being dependent on the end application - e.g. a road sign may have a circular shape.
  • the removal of the fastener from the aperture may be a function of the prying action that is caused on the fastener.
  • This prying action may be a function of the force in the system (F) and the offset between the two points of bearing (L), whereby the prying action can be defined as the product of the two (F x L) called the prying moment (M).
  • F force in the system
  • L offset between the two points of bearing
  • M prying moment
  • the amount of material from the deformable washer that overlaps the top of the first member may also be controlled thereby providing further ability to tune the performance of the system.
  • Equally material from other locations along the pathway of the aperture may also be forced inward to interfere with the pathway of the fastener. This may include one or more interference location on one or more sides of the aperture.
  • a directing means may protrude into the aperture of the first or second member to interfere with the motion of the fastener.
  • the directing means may protrude into the top of the aperture of the first or second member.
  • the directing means may prevent the fastener from overlapping with the material on the front face of the first or second member.
  • the directing means may be formed from a material with at least one crease or fold in the length of the material. This crease or fold may significantly increase the directing means capacity to resist the forces applied from the fastener.
  • the directing means may be deformed and creased in a single action thereby making it both economic to manufacture and strong.
  • a separate element may be used (e.g. another fastener) to cause the same effect e.g. the washer and fastener slide up until they hit a second fastener which causes the prying action.
  • the location of the aperture on the face of the first member may be remote from the top of the member or members and therefore the system performance may be unaffected by damage that may have been caused to the top of the member or members during manufacturing, handling, or installation. This makes this form of system resilient to damage, an issue which can plague art systems.
  • connection formed between the first member and the second member may use conventional fasteners. This may reduce the need for special components and may ease maintenance issues.
  • the at least one fastener may be reusable.
  • One end of the at least one fastener may be located on the outwards facing side of the second member and may have a smooth shape.
  • Outwards refers to the side of the second member that a vehicle or other object might impact against.
  • a smooth shape may be preferable as this avoids objects and vehicles snagging or catching on the fastener(s).
  • the vehicle/object slides along the second member during an impact in order to help redirect and guide the vehicle/object to safety. It should be appreciated that this orientation is not necessary for the system to work, and alternative orientations of fasteners may be applied.
  • the at least one fastener may be a bolt with a male thread that threads directly into a nut, the washer abutting the nut or bolt head spending on the bolt orientation relative to the post.
  • the bolt as used above may be an M 16 bolt although it should be appreciated that a range of other bolt sizes may be used and the same or similar outcomes achieved. Reference to a bolt should not be seen as limiting as the fastener make take a variety of different forms.
  • the first member may have generally upright/vertical position once driven into the ground.
  • First members in the assembled form may be spaced at varying distances such as 1, or 1.5, or 2, or 2.5, or 3 metre intervals, or as necessary to locate with the mounting location on the second member.
  • the overall system length may be varied to suit the end application.
  • the barrier as a whole may have terminating ends.
  • the terminating ends may be of varying design to the wider barrier configuration.
  • the terminating ends may incorporate the system described herein to releasably retain the terminal ends or a part thereof.
  • the second member or longitudinal beam may follow a generally horizontal alignment, in the case of a road barrier, typically following the road contours and having a constant height above the road commensurate with where a vehicle/object or part thereof might impact the second
  • the indirect link described above is described in the context of joining a first member to a second member.
  • the indirect link could be installed onto an intermediary member such as a block-out component.
  • the block-out could be rigidly attached to the first member and then the washer used to connect the block-out to the second member. This could be a useful option for retrofitting existing systems without removing and replacing the first members. Existing block-outs could simply be removed and replaced with the new block-out containing the washer connection detail.
  • the blockout could be rigidly fastened to the longitudinal beam and connected to the post via the deformable connection, or connected to both the beam and post using the deformable connection.
  • a fastener may be inserted through the second member (in the application of a longitudinal beam, typically inserted about the mid-section) and the fastener may be threaded through the first member aperture, washer and nut before being fixed in place by tightening the nut ensuring that the second member load is transferred cross the fastener/washer.
  • the washer may for example be a nut or a bolt head and the same method of assembly is used albeit without adding a separate washer.
  • installation is relatively simple - for example, install the first member/post separately, and attach the second member/longitudinal beam. This simple method avoids damage on installation to the connection point as the washer and fastener are fitted after first member driving.
  • the performance of the system may be very tuneable with regards to pull out force and/or pull out displacement. Once designed, the system may be insensitive to tolerances, unlike the art systems which can have significant variations in pull out forces.
  • the system as described may be insensitive to the location of the connection formed between the members and, for longitudinal beams, insensitive to the location of splice joints used to connect the individual lengths of longitudinal beam.
  • the second member may typically be heavily stressed (loaded) during a force impact.
  • the ability to tune the system described herein prevents it from adding additional loads to the second member and therefore limits the potential for unwanted failure modes such as tearing or failure of the second member. All art systems have specific failure modes that they cannot prevent which can result in additional forces being placed into the second member and could result in failure of the second member in certain circumstances.
  • the system as described may also have sufficient tolerance and movement to allow for movement caused by temperature (thermal expansion and contraction). This may be an important characteristic to prevent unwanted structural weakening or breakage.
  • Barrier post foot plate fixings - the foot plate to ground connection may need to be releasable to allow the entire post to release from the ground in the event of an impact;
  • Lifeline connections for fall protection the washer being designed to progressively release to dissipate energy in a fall or limit the load on the lifeline connection;
  • the system may also minimise stress points on the member or members ensuring that the member or members do not fail in an unpredictable way in the event of an impact.
  • the system can translate one form of motion or force vector which doesn't apply a sufficient force to the washer to cause deformation into a second force vector or motion which does apply a force of sufficient strength to deform a region on the washer. Equally, the system can be constructed to undertake the opposite, thereby changing the motion or applied force so as to reduce the deformable load applied to the washer.
  • the system comprises of three key components; the longitudinal beam 1 (second member), the posts 2 (first members), and the connection detail comprising a deformable washer 10 and fastener 3.
  • An assembled system is shown in Figure 17 and Figure 18 with images of the system post impact shown in Figures 19-22.
  • a general description of the components is provided below. Please note that these are only provided by way of example.
  • the longitudinal beam 1 is required to form a continuous element along the length of the barrier. It is most commonly manufactured from short lengths of structural section which are joined at regular intervals to form a continuous member.
  • the shape of the longitudinal beam 1 could take many forms, but most commonly for a roadside barrier the longitudinal beam 1 will be a W-beam section, a Thrie beam section, a box beam, or a C channel . Alternatively it could be a cable or wire.
  • the longitudinal beams 1 are provided in lengths of up to 4.2 m and joined together with a bolted connection, either by overlapping the sections or butting the sections together and using a third jointing member.
  • the longitudinal beam 1 is required to have the necessary structural properties to operate correctly as a barrier whilst also being economic to manufacture, simple to bend for concave and convex corners, whilst also being economic to install.
  • the longitudinal beam 1 typically comes preformed with a mounting slot located at regular intervals.
  • the slots are used to attach the longitudinal beam 1 to the post 2.
  • the slots run longitudinally along the length of the barrier and provide tolerance for the lateral placement of the post 2.
  • the longitudinal beams 1 are typically off-the-shelf components that are purpose-built for the application. It is desirable to not modify an existing system.
  • the posts 2 are used to provide vertical support to the longitudinal beam 1 at regular intervals so as the beam 1 is at the correct height and to provide resistance to the backward deflection of the longitudinal beam 1 when impacted by a vehicle.
  • the posts 2 are installed directly into the soil by being driven (impacted) into the ground to the desired height.
  • posts 2 may also be installed by being placed into preformed holes and then compacted around or being encased in concrete.
  • the posts 2 can also be installed onto a hardened surface (concrete, asphalt, etc). This is typically achieved by having a baseplate detail on the bottom of the posts 2 which is then bolted or bonded to the surface.
  • the post 2 can be of any geometric shape, provided they have a surface that mates to the back of the longitudinal beam 1 section to allow the connection to be formed. This surface must have a sufficient width to allow the connection detail to be formed in the post 2.
  • the posts 2 would have the cross sectional shape of an I-beam, C channel, boxed section, U post, Z post, or ⁇ post. However, other post 2 shapes are also possible.
  • the face of the post 2 that mates with the longitudinal beam 1 section (defined as the front of the post 2) will have a specific detail located in it to form the connection with the longitudinal beam 1.
  • the connection is formed by the fastener 3 and the washer 10 (described in the following section), and the detail on the post 2.
  • connection between the post 2 and the longitudinal beam 1 is formed using a conventional fastener 3 and a specially manufactured deformable washer 10.
  • the fastener 3 could take any form but it is envisaged it would be a conventional bolt and nut arrangement commonly used in barrier applications. It is envisaged that the bolt would be passed through the longitudinal beam 1 and into the post 2. The washer 10 would then be installed on the bolt before the nut is installed and tightened.
  • the deformable washer 10 is integral to the performance of the system.
  • the properties of this washer 10 can be altered to tune the performance of the washer 10 in order to achieve the desired behaviour of the system.
  • Key variables that could be altered on the washer 10 include material properties, thickness, number of cut-outs, size and shape of cut-outs, location of cut-outs, dimensions relative to the detail in the post 2, profile of the washer 10 (cupped or flat), symmetry of the washer 10 (both lateral and vertical), shape of the washer 10 (square, round, rectangle, etc).
  • Some example washer 10 shapes are shown by way of example in Figure 8. Accordingly the performance of the washer 10 is very tuneable for the desired outcome.
  • the internal dimension of the post 2 is required to have a width greater than that of the widest part of the fastener 3 that is used in the connector, so that the fastener 3 can move unobstructed through the aperture 4. Typically this would be the widest part of the nut used in conjunction with a bolt (not shown in Figure 9). There must also be additional width on the front face of the post 2 to allow the deformable washer 10 detail to bear on the rear side of the front face of the post 2 with sufficient area so as to provide a suitable pull out resistance.
  • the deformable washer 10 can be sized to ensure it bears on the internal edge of the post 2 and thereby prevents sufficient lateral movement so as to prevent the nut from engaging with the material on the front face of the post 2.
  • the shape of the post 2 or the dimension of the washer 10 can be modified accordingly.
  • the detail in the post 2 can be formed as an elongated slot (as shown above) to allow the fastener 3 vertical tolerance for installation and to allow the longitudinal beam 1 the ability to move up the post 2 as the post 2 deforms backwards when the system is impacted by an errant vehicle.
  • the detail could be formed without vertical tolerance and take more of the shape of a hole rather than a slot.
  • the detail could be installed in the post 2 rotated 90 degrees thereby providing the system with movement in the horizontal direction.
  • the bottom of the detail can be formed so that it limits the downward motion of the fastener 3. This can be achieved with a radius or a flat (square) bottom.
  • the washer 10 detail overlaps the front face of the post 2 and provides additional resistance to pull-out force in the direction perpendicular to the face of the post 2 and to pull-out forces associated with twisting of the post 2.
  • the bottom 5 of the slot 4 can be formed with a section 6 of the front face of the post 2 folded inward as shown in Figure 10 which therefore prevents the bottom of the washer 10 from overlapping with the front face of the post 2 and ensure that only the side of the washer 10 engages with the post 2. In this orientation the fastener 3 is suspended above the bottom of the aperture 4 by the washer 10 sitting on the folded tab section 6.
  • the fastener 3 and the deformable washer 10 used to connect the longitudinal beam 1 to the post 2 can move up the detail in the post 2 until they impact the top of the detail. If during this motion the force vector placed on the connection is sufficient the release capacity of the washer 10 will be overcome and the edge or edges of the washer 10 will deform thereby allowing the fastener 3 to either pull free of or loosen its grip on the post 2.
  • the shape can be formed in any number of ways to control the behaviour of the system. If the shape has a flat or outward radius end then the fastener 3 will impact the end of the detail and the washer 10 will overlap with the front face of the post 2. Once this occurs, the fastener 3 will then rotate relative to the face of the post 2 due to the moment couple created from the offset of the thickness of the longitudinal beam 1 element and the thickness of the post 2. When the force created by the prying motion exceeds the capacity of the washer 10, the deformable regions of the washer 10 will deform and allow the fastener 3 to separate from the post 2 thereby separating the longitudinal beam 1 from the post 2 element.
  • top of the post 2 aperture 4 detail in the post 2 is formed with an alternative shape it can limit the potential overlap between the washer 10 and the material in the front face of the post 2 at the top of the detail and therefore reduce the force to pry out.
  • alternative shapes such as in inward radius or serpentine shape are shown in Figure 9.
  • the removal of the fastener 3 from the slot 4 is primarily a function of the prying action that is caused on the fastener 3.
  • this prying action is a function of the force in the system (F) and the offset between the two points of bearing (L), whereby the prying action can be defined as the product of the two (F x L) called the prying moment (M).
  • F force in the system
  • L offset between the two points of bearing
  • M the prying moment
  • the amount of material from the deformable washer 10 that overlaps the top of the post 2 can also be controlled thereby providing further ability to tune the performance of the system.
  • the barrier is required to deflect backwards.
  • This backward motion places the longitudinal beam 1 into tension due to the increase in length required to support the backward motion.
  • An effect of this motion is that the longitudinal beam 1 element is forced to move towards the point of impact from either side, causing a relative force vector and/or relative lateral movement between the posts 2 and the longitudinal beam 1.
  • this places a relative movement (left to right) on the posts 2 upstream of the point of impact and a relative movement of right to left on the downstream posts 2 resulting from an impact occurring from the left hand direction. If the dimensions of the deformable washer 10 and the edges of the post 2 are sufficiently tight then this relative movement can be constrained by the washer 10 bearing on the internal edges of the post 2.
  • the optimal performance of a barrier system may be obtained by retaining the connection between the post 2 and the longitudinal beam 1 for all posts 2 upstream from the point of impact - see Figure 22 for example - while allowing the posts 2 downstream to disconnect from the longitudinal beam 1 thereby preventing the longitudinal beam 1 from being dragged downward as the posts 2 are deflected - see Figures 19-21 for example.
  • the different relative lateral movement of the longitudinal beam 1 to the posts 2 in the upstream and downstream directions can be used to provide an increased resistance to release force upstream and downstream.
  • the system can be tuned to provide different release loads between the system upstream 100 and downstream 200 from the point of impact, as shown in Figure 13 and Figure 14.
  • a circular deformable washer 10 ensures a consistent performance independent of the orientation of the washer 10. This makes for an easier installation.
  • other shapes and details can be used for the washer 10 that alters the release load or deflection of system when loaded in different directions or orientations. This can be used to optimise the performance of the system for specific applications.
  • the washer 10 can be manufactured as a flat surface or it can be cupped so that it fits into the detail formed in the post 2 and bears directly on the back surface of the longitudinal beam 1 element, or somewhere in between. Examples of flat and cupped washers 10 are shown in Figure 15. By varying the cupping of the washer 10 the degree of friction formed between the washer 10 and the post 2 can be altered. Changing the clamping friction can help tune the force required to move the longitudinal beam 1 relative to the post 2 in direction of the interface plane. Additionally, changing the external dimensions of the washer 10 can result in differing degrees of relative movement required between the washer 10 and the post 2 prior to the beam 1 being released. A washer with a larger perimeter will require a greater relative movement prior to a release being formed.
  • the location of the detail on the face of the post 2 is remote from the top of the posts 2 and therefore its performance will be unaffected by damage that may have been caused to the top of the posts 2 during installation. This makes this form of release mechanism resilient to damage, an issue which plagues the art systems. Furthermore the connection formed between the post 2 and the longitudinal beam 1 can use conventional fasteners typically used in this form of construction. This reduces the need for special components and eases maintenance issues.
  • Some art systems have less tolerance for installation, with either limited vertical tolerance or a lack of rotational tolerance relative between the post 2 and the longitudinal beam 1.
  • Systems which require a bolt to be inserted directly into threaded hole can be difficult to install, particularly for installations that require variations in horizontal or vertical alignment.
  • the barrier system described herein has tolerance in all directions and is simple to install.
  • the use of a conventional bolt and nut arrangement with a deformable washer 10 allows the system to be installed using conventional tools and with conventional tolerances without any additional care.
  • the performance of the system is very tuneable with regards to pull out force and/or pull out displacement. Once designed, the system is insensitive to tolerances, unlike the system in US 7,878,486 which has significant variations in pull out forces depending on where the system is located in to the slot of the w-beam.
  • the system as described is insensitive to the location of the connection formed between the post 2 and the longitudinal beam 1 and the splice joints used to connect the individual lengths of longitudinal beam 1.
  • the longitudinal beam 1 element is typically heavily stressed (loaded) during an impact event.
  • the ability to tune the barrier system described herein prevents it from adding additional loads to the longitudinal beam 1 and therefore limits the potential for unwanted failure modes such as tearing or failure of the longitudinal beam 1. All other systems have specific failure modes that they cannot prevent which can result in additional forces being placed into the longitudinal beam 1 and could result in failure of the longitudinal beam 1 in certain circumstances.
  • the novel connection detail can be used with a variety of post 2 shapes. It can also be used in a back-to-back longitudinal beam 1 configuration (defined as a median configuration) with longitudinal beam 1 installed on both sides of a post 2. It an can also be used with block-outs installed between the post 2 and the rail, with the deformable connection used either between the rail and the blockout or the blockout and the post 2. When installed in a back to back configurations, this could have block-outs on one, both, or no-sides.
  • the detail could be installed onto a block-out component.
  • the block out could be rigidly attached to the post 2 and then the washer 10 and detail 4 used to connect the block-out to the longitudinal beam 1.
  • This could be a useful option for retrofitting existing barrier systems without removing and replacing the posts 2.
  • the existing block-outs could simply be removed and replaced with the new block-out containing the washer 10 connection detail. It an can also be used with the deformable connection between the blockout and the post 2, thereby separating the block-out and post 2 when released.
  • the system could be installed with block-outs on one side, both siders or with no block-outs.
  • connection detail located on the post 2 with a simple aperture 4 or slot located on the longitudinal beam 1.
  • the system would work equally with the connection detail on the longitudinal beam 1 and a simple connection point on the post 2.
  • the connection could be tuned 90 degrees (or any other angle) and could be used to provide a releasing mechanism with tolerance for lateral movement (or movement in any direction).
  • the connection could be formed with the detail on both the rail and post 2, with the details angularly separated so as to provide variable releasing forcing under varying applied loads in all directions.
  • system described herein may be used for a variety of other applications including for example, retention and release of barrier posts, car parking barriers, signs and light posts.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Bolts, Nuts, And Washers (AREA)

Abstract

La présente invention concerne un système de retenue et de libération dépendant de la force, le système liant des éléments ensemble d'une manière libérable en fonction d'une force appliquée par l'intermédiaire d'au moins un moyen de retenue réglable. La libération peut être réalisée en fonction à la fois de l'amplitude et de la direction de la force pour que la libération puisse être un résultat de différentes forces de libération dans différents angles de force. Le moyen de retenue peut être au moins une rondelle déformable. La rondelle déformable peut être conçue pour transférer une force de charge d'un premier élément par l'intermédiaire d'un dispositif de fixation à un second élément, la rondelle s'étendant autour du dispositif de fixation et possédant une première face qui s'appuie sur le dispositif de fixation ou une partie de celui-ci (ou fait partie du dispositif de fixation) et une face opposée qui s'appuie au moins partiellement sur une partie du premier élément et/ou du second élément. La rondelle est conçue pour que, dans le cas d'une force d'amplitude suffisante, sur l'un ou les deux éléments, la rondelle se déforme au moins partiellement, permettant aux éléments de se séparer.
PCT/NZ2017/050040 2016-04-08 2017-04-07 Système de retenue et de libération dépendant de la force WO2017176129A1 (fr)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060011900A1 (en) * 2004-07-19 2006-01-19 Ochoa Carlos M Releasable highway safety structures
US8807536B2 (en) * 2007-08-21 2014-08-19 Nucor Corporation Roadway guardrail system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20060011900A1 (en) * 2004-07-19 2006-01-19 Ochoa Carlos M Releasable highway safety structures
US8807536B2 (en) * 2007-08-21 2014-08-19 Nucor Corporation Roadway guardrail system

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