Impact attenuator

Abstract

An impact attenuator (100) for attachment to a host vehicle, comprising: a front end frame (105) and a rear end frame (110), an elongated first curved side wall (115) and an elongated second curved side wall (120) attached to the front end frame (105) and the rear end frame (110), an arc-shaped front module (125) attached to the front end frame (105), an arc-shaped rear module (130) attached to the rear end frame (110), an energy absorbing module (128) arranged within an open area between the arc-shaped front module (125) and the arc-shaped rear module (130).

Description

[0001] IMPACT ATTENUATOR

[0002] Technical Field

[0003] The present disclosure relates to impact attenuators, and more particularly to an impact attenuator for attachment to a host vehicle.

[0004] Background

[0005] Impact attenuators, also known as crash cushions or crash attenuators, are safety devices designed to reduce the severity of vehicle collisions by absorbing and dissipating kinetic energy. They are typically installed at the ends of barriers, guardrails, or other roadside structures to protect motorists and reduce the risk of injuries and fatalities in the event of a crash. Impact attenuators are commonly found on highways, bridges, construction zones, and other high-risk areas.

[0006] The absorption and dissipation of the kinetic energy generated during a collision is achieved through various mechanisms such as deformation of materials, crushing of structural components, or compression of specialized elements within the impact attenuator device. By absorbing and redirecting the energy of a colliding vehicle, impact attenuators can prevent vehicles from penetrating barriers or other structures, thus mitigating the risk of injuries and fatalities.

[0007] Impact attenuators may have various designs and configurations, each tailored to specific applications and impact scenarios. Common types include water-filled barriers, sand-filled barrels, crushable foam modules, steel or concrete crash cushions, and hybrid systems combining different materials and mechanisms for energy absorption.

[0008] Impact attenuators are subject to rigorous testing and certification according to established performance standards, such as those outlined by organizations like the American Association of State Highway and Transportation Officials (AASHTO) and the Federal Highway Administration (FHWA). These standards ensure that attenuators meet specific criteria for impact resistance, durability, and effectiveness in reducing crash severity.

[0009] Overall, impact attenuators play a vital role in enhancing road safety by reducing the severity of vehicle collisions and protecting motorists and passengers from harm. Their effectiveness depends on factors such as design, construction quality, proper installation, etc. A Truck Mounted Attenuator (TMA) is a safety device used on highways and roads to protect both road workers and motorists. It is typically mounted on the rear of a truck, which is often positioned in a stationary or slow-moving position to protect workers and equipment in a work zone. The TMA absorbs the impact of an errant vehicle, reducing the severity of collisions and minimizing damage and injuries.

[0010] The design of a TMA usually consists of a series of impact-absorbing components, such as collapsible elements or cushioning materials, housed within a rigid frame. When a vehicle strikes the TMA, these components deform or compress, absorbing and dissipating the kinetic energy of the impact. This action helps to prevent the vehicle from penetrating further into the work zone, thus safeguarding workers and equipment.

[0011] TMA units are typically constructed to meet the specific standard according to the MASH (Manual for Assessing Safety Hardware) guidelines set by the American Association of State Highway and Transportation Officials (AASHTO). They are designed to be highly visible to approaching motorists, often featuring reflective markings and warning lights to alert drivers to the presence of the work zone and the TMA-equipped truck.

[0012] Overall, Truck Mounted Attenuators play a crucial role in improving safety on highways and roads by providing a protective barrier between moving traffic and workers in construction or maintenance zones.

[0013] EP 1064172 describes a crash impact attenuator designed to be mounted on a service truck or other vehicle. The attenuator has an elongated profile outlined by the perimeter band. The perimeter band is a section of high molecular weight / high density polyethylene pipe. The section of pipe has been converted from a circular profile to an elongated profile by a loop of cable extending from diametrically opposed sides of the pipe and tightened to pull the sides toward each other. Mounted inside the perimeter of the perimeter band are two front cylinders. These cylinders are made of the same material as is the perimeter band.

[0014] A disadvantage of the crash impact attenuator according to EP1065172 is that it has a relatively high weight. Moreover, the pre-tensioning of the tube by means of the loop cable to create the elongated profile makes the device unstable and impairs the material's ability to withstand the stresses of a collision.

[0015] US6581992 describes a tuck mounted attenuator (TMA). The TMA is comprised of a strut and a cartridge. The TMA strut is attached to a backup that is rigidly attached to the truck rear end. The TMA cartridge is pivotally attached to the strut and is located behind the truck. The cartridge includes a pair of vertically spaced outwardly curved members, and the strut similarly includes a pair of vertically spaced outwardly curved members designed to buckle upon application to the TMA of forces resulting from vehicular impact. These members comprise aluminium tubing. The TMA has an open construction with a plurality of energy absorbent cartridges constructed of an aluminium honeycomb material disposed in environmentally sealed aluminium containers.

[0016] Since the device consists of two parts, which are pivotable in relation to each other, it makes the TMA more complex but at the same time unstable. In order to meet set requirements for safety, more parts are required, which makes the entire construction heavier, not least because of the plurality of energy absorbent cartridges constructed of expensive honeycomb material.

[0017] Prior art crash impact attenuators and TMAs involve many different components, both movable and fixed, which in many cases are costly.

[0018] The present inventor has realized that there is room for improvements in this regard. Hence, the present inventor has identified both the need for and the benefits of a novel and inventive impact attenuator.

[0019] Summary

[0020] It is an object of the teachings of this application to obviate at least some of the above disadvantages and to provide an improved impact attenuator.

[0021] According to a first aspect, this is achieved by an impact attenuator for attachment to a host vehicle, comprising: a front end frame and a rear end frame, an elongated first curved side wall and an elongated second curved side wall attached to the front end frame and the rear end frame, wherein the front end frame, the rear end frame, the first curved side wall, and the second curved side wall form an elongated frame, surrounding an open area, an arc-shaped front module arranged within said open area and attached to the front end frame, an arc-shaped rear module arranged within said open area and attached to the rear end frame, an energy absorbing module arranged within the open area between the arcshaped front module and the arc-shaped rear module, crossed first and second metal rods attached to the front end frame at respective endpoints of the arc-shaped front module and to opposite points on the inside of the arcshaped front module, crossed third and fourth metal rods attached to the rear end frame between endpoints of the arc-shaped rear module and to opposite points on the inside of the rear module, a fifth metal rod attached to the middle of the elongated first curved side wall and to a first point on an envelope surface of the arc-shaped front module, a sixth metal rod attached to the middle of the elongated second curved side wall and to a second point on the envelope surface of the arc-shaped front module, a seventh metal rod attached to the middle of the elongated first curved side wall and to a first point of an envelope surface of the arc-shaped rear module, and an eight metal rod attached to the middle of the elongated second curved side wall and to a second point on the envelope surface of the arc-shaped rear module .

[0022] In an advantageous embodiment, the energy absorbing module is attached to the envelope surface of the arc-shaped front module facing the rear module.

[0023] In some embodiments, the front module including the energy absorbing module is arranged at a distance from the rear module.

[0024] In an advantageous embodiment, the crossed first and second metal rods and the crossed third and fourth metal rods comprises one or more pairs of crossed first and second metal rods) and one or more pairs of crossed third and fourth metal rods.

[0025] In an advantageous embodiment, the fifth, sixth, seventh, and eight metal rods comprises one or more pairs of the fifth, sixth, seventh, and eight metal rods.

[0026] In some embodiments, each of the elongated first and second curved side walls are attached to brackets of the front end frame and brackets of the of the rear end frame, respectively.

[0027] In an advantageous embodiment, each of the elongated first and second curved side walls is provided with vertical buckling grooves spaced apart on the inside of the respective side wall.

[0028] In an advantageous embodiment, two of the vertical buckling grooves are spaced apart on a front half of each of the elongated first and second curved side walls, and one vertical buckling groove on a rear half of each of the elongated first and second curved side walls. In an advantageous embodiment, each of the elongated first and second curved side walls comprises three elongated curved beams arranged on top of each other.

[0029] In an advantageous embodiment, the arc-shaped front module comprises three arc-shaped front elements arranged on top of each other, and the arc-shaped rear module comprises three arc-shaped rear elements arranged on top of each other.

[0030] In an advantageous embodiment, the arc-shaped front module forming a circular arc of about 240°-280° between the end points of the arc-shaped front module.

[0031] In an advantageous embodiment, the arc-shaped rear module forming a circular arc of about 240°-280° between the end points of the arc-shaped rear module.

[0032] In some embodiments, the energy absorbing module has an aluminium honeycomb core.

[0033] In some embodiments, the impact attenuator comprises a truck mounting arrangement for attachment of the impact attenuator to the host vehicle, wherein the front end frame is attached to the truck mounting arrangement, thereby forming a cantilever impact attenuator.

[0034] In some embodiments, the elongated first curved side wall, the elongated second curved side wall, the arc-shaped front module, and the arc-shaped rear module are made of a first aluminium alloy.

[0035] In an advantageous embodiment, the first aluminium alloy is aluminium 6063- T4, or any other aluminium alloy with similar properties.

[0036] In some embodiments, the rear end frame, brackets for attachment of the energy absorbing module and brackets for attachment of the arc-shaped front module and the arc-shaped rear module are made of a second aluminium alloy.

[0037] In an advantageous embodiment, the second aluminium alloy is aluminium 6082-T6, or any other aluminium alloy with similar properties.

[0038] In some embodiments, the metal rods are made of stainless steel.

[0039] In an advantageous embodiment, the stainless steel is 316L, or any other stainless steel with similar properties.

[0040] In an advantageous embodiment, the impact attenuator is a Truck Mounted Attenuator, TMA.

[0041] In some embodiments, the impact attenuator is a trailer mounted attenuator comprising a trailer frame, a wheel set, and a trailer coupler for connection to the host vehicle.

[0042] An advantage of some embodiments of the present disclosure is that the impact attenuator is less complex, i.e comprises few components, and has reduced weight. Another advantage of some embodiments of the present disclosure is that the impact attenuator has few moving parts.

[0043] Moreover, the impact attenuator has a modular design, allowing for easier maintenance and replacement of damaged components.

[0044] Still another advantage is that the inventive impact attenuator meets the specific standard according to the MASH (Manual for Assessing Safety Hardware) guidelines.

[0045] Other aspects and features of the invention and its embodiments are further explained in the detailed description and the drawings, and are defined by the appended claims.

[0046] It should be emphasized that the term “comprises / comprising” when used in this specification is taken to specify the presence of stated features, integers, steps, or components, but does not preclude the presence or addition of one or more other features, integers, steps, components, or groups thereof.

[0047] All terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a / an / the element, device, component, means, etc are to be interpreted openly as referring to at least one instance of the element, device, component, means, etc., unless explicitly stated otherwise.

[0048] Brief Description of the Drawings

[0049] Further objects, features and advantages will appear from the following detailed description of embodiments, with reference being made to the accompanying drawings, in which:

[0050] FIG. l is a perspective view of an impact attenuator according to an embodiment;

[0051] FIG. 2A is a top view of the impact attenuator of FIG. 1;

[0052] FIG. 2B is a side view of the impact attenuator of FIG. 1;

[0053] FIG. 3 A is a top view or a bottom view of an energy absorbing curved beam of the impact attenuator of FIG. 1;

[0054] FIG. 3B is a first side view of the energy absorbing curved beam of FIG. 3 A;

[0055] FIG. 3C is a second side view of the energy absorbing curved beam of FIG.

[0056] 3 A;

[0057] FIG. 3D is an enlarged cross sectional view along the line IIID-IIID in FIG.

[0058] 3 A; FIG. 4A is a side view of an arc-shaped front element of an energy absorbing arc-shaped front module of the impact attenuator of FIG. 1;

[0059] FIG. 4B is a top view of the arc-shaped front element of FIG. 4A;

[0060] FIG. 4C is a cross sectional view along the line IVC-IVC in FIG. 4B;

[0061] FIG. 5A is a side view of an arc-shaped rear element of an energy absorbing arc-shaped rear module of the impact attenuator of FIG. 1;

[0062] FIG. 5B is a top view of the arc-shaped rear element in FIG. 5A; and

[0063] FIG. 5C is a cross sectional view along the line VC-VC in FIG. 5A.

[0064] Detailed Description

[0065] Embodiments of the invention will be described with reference to FIGs. 1-5, which illustrate schematically an example arrangement to some embodiments. The same reference signs are used for corresponding features in different figures. The terminology used in the detailed description and drawings of the embodiments are not intended to be limiting.

[0066] The following description describes embodiments applicable to the field of impact attenuators, also known as crash cushions or crash attenuators, including Truck Mounted Attenuators (TMAs) or trailer mounted attenuators for attachment to a host or shadow vehicle, such as a truck. The TMA is designed to absorb the impact of an errant vehicle, reducing the severity of collisions and minimizing damage and injuries.

[0067] The absorption and dissipation of the kinetic energy generated during a collision is achieved through various mechanisms such as deformation of materials, crushing of structural components, or compression of specialized elements within the impact attenuator. By absorbing and redirecting the energy of a colliding vehicle, the impact attenuator mitigates the risk of injuries and fatalities.

[0068] FIG. 1 shows an embodiment of an impact attenuator 100 for attachment to a host vehicle. The impact attenuator 100 comprises a front end frame 105 and a rear end frame 110, an elongated first curved side wall 115 and an elongated second curved side wall 120 attached to the front end frame 105 and the rear end frame 110. The first curved side wall 115 and the second curved side wall 120 are securely attached to the front end frame 105 and the rear end frame 110.

[0069] Referring to FIG. 1 and FIG 2A, the front end frame 105, the rear end frame 110, the first curved side wall 115, and the second curved side wall 120 are attached to each other, thereby form an elongated frame 121, surrounding an open area. In this embodiment, the front end frame 105 is pivotally attached to a truck mounting arrangement 112, wherein the impact attenuator 100 may be moved between a horizontal use position as illustrated in FIG. 1 and a vertical transport position. The truck mounting arrangement 112 is made of steel or any other rigid material.

[0070] Further, an arc-shaped front module 125 is arranged within the open area, wherein end points 126, 127 of the arc-shaped front module 125 are attached to the front end frame 105, preferably by means of brackets 126a, 127a and screw fastenings. In this embodiment the arc-shaped front module 125 comprises, but is not limited to, three arcshaped front elements 181-183 arranged on top of each other.

[0071] An energy absorbing module 128, preferably, but not limited to, a honeycomb module, is arranged within the open area between the arc-shaped front module 125 and the arc-shaped rear module 130. In this embodiment, the energy absorbing module 128 is attached to the envelope surface of the arc-shaped front module 125 at a distance from and facing the rear module 130. The attachment of the energy absorbing module 128 to the arc-shaped front module 125 is provided preferably by means of brackets 128a, 128b and screw fastenings.

[0072] In addition, an arc-shaped rear module 130 is arranged within the open area, wherein end points 131, 132 of the arc-shaped rear module 130 are attached to the rear end frame 110, preferably by means of brackets 131a, 132a and screw fastenings. In this embodiment the arc-shaped rear module 130 comprises, but is not limited to, three arcshaped rear elements 184-186 arranged on top of each other.

[0073] In this embodiment, the three arc-shaped front elements 181-183 and three arcshaped rear elements 184-186 may be extruded aluminum profiles.

[0074] As illustrated in FIG. 1 and FIG. 2A, first and second pairs of crossed metal rods 135, 135’; 136, 136’ are attached to the front end frame 105 at the respective endpoints 126, 127 of the arc-shaped front module 125 and to opposite points on the inside of the front module 125, close to attachment points of the brackets 128a, 128b of the energy absorbing module 128.

[0075] Third and fourth pairs of crossed metal rods 137, 137’; 138, 138’ are attached to the rear end frame 110 at attachment points between the endpoints 131, 132 of the arc-shaped rear module 130 and to opposite points on the inside of the arc-shaped rear module 130.

[0076] A fifth pair of metal rods 139, 139’ are attached to an anchor plate 143 in the middle of the elongated first curved side wall 115 and to the arc-shaped front module 125, adjacent to a first side of the energy absorbing module 128 close to the bracket 140’ are attached to the middle of the elongated second curved side wall 120 and to the arc-shaped front module 125 adjacent to a second side of the energy absorbing module 128 close to attachment point of the bracket 128b of the energy absorbing module 128.

[0077] A seventh pair of metal rods 141, 141’ are attached to an anchor plate 143 in the middle of the elongated first curved side wall 115 and to the arc-shaped rear module 130 at the same positions as the fourth pair of metal rods 138, 138’ but on the envelope side of the arc-shaped rear module 130. An eight pair of metal rods 142, 142’ are attached to an anchor plate 144 in the middle of the elongated second curved side wall 120 and to the arc-shaped rear module 130 at the same position as the third pair of metal rods 137, 137’ but on the envelope side of the arc-shaped rear module 130.

[0078] Hence, the first pair of metal rods 135, 135’ and the sixth pair of metal rods 140, 140’ form two portions of slightly broken lines from the attachment points of the front end frame 105 to the middle point of the second curved side wall 120, and the second pair of metal rods 136, 136’ and the fifth pair of metal rods 139, 139’ form two portions of slightly broken lines from the attachment points of the front end frame 105 to the middle point of the first curved side wall 115.

[0079] Hence, the third pair of metal rods 137, 137’ and the eight pair of metal rods 142, 142’ form straight lines from the attachment points of the rear end frame 110 to the middle point of the second curved side wall 120, and the fourth pair of metal rods 138, 138’ and the seventh pair of metal rods 141, 141’ form straight lines from the attachment point of the rear end frame 110 to the middle point of the first curved side wall 115.

[0080] The first to eight pairs of metal rods 135, 135’ to 142, 142’ are preferably attached by means of screw fastenings providing secure attachment points and ensure proper alignment and stability during operation of the impact attenuator 100.

[0081] As illustrated in FIG 1 and FIG 2A, each of the elongated first and second curved side walls 115, 120 is provided with vertical buckling grooves 151-153 spaced apart on the inside of the respective wall 115, 120. In this embodiment two of the vertical buckling grooves 151, 152 are spaced apart on the front half of each of the elongated first and second curved side walls 115, 120, and one vertical buckling groove 153 on the rear half of each of the elongated first and second curved side walls 115, 120.

[0082] Referring to FIG. 2B, the elongated first curved side wall 115 of the impact attenuator 100 comprises three elongated curved beams 161-163 arranged on top of each other and attached to the front end frame 105 and the rear end frame 110 by means of the beam brackets 105a, 110a and screw fastenings. Correspondingly, as shown in FIG 1, the elongated second curved side wall 120 of the impact attenuator 100 comprises three elongated curved beams 164-166 arranged on top of each other and attached to the front end frame 105 and the rear end frame 110 by means of the brackets 105b, 110b.

[0083] The brackets 105a, 105b, 110a, 110b, 126a, 127a, 128a, 128b, 131a, 132a and the screw fastenings provide secure attachment points and ensure proper alignment and stability during use of the impact attenuator 100.

[0084] Since all of the elongated curved beams 161-166 may be identical, only one of the beams, i.e. beam 164 of the elongated second side wall 120, is described herein with reference to FIGs. 3 A-3D.

[0085] Hence, FIG. 3 A is a top view of the energy absorbing curved beam 164 of the elongated second curved side wall 120 of the impact attenuator 100. However, the top view of the beams 164-166 of the elongated second curved side wall 120 corresponds to the bottom view of the beams 161-163 of the elongated first curved side wall 115. In this embodiment, the elongated curved beam 164 may have a length of 3.5 - 4.0 m, but preferably about 3.7 m, and a bending radius of 7.0 - 7.5m, but preferably about 7.3 m.

[0086] FIG. 3B is a first side view of the energy absorbing curved beam 164, i.e. as it appears from the inside of the impact attenuator 100, illustrating the position of the vertical buckling grooves 151, 152, 153. In this embodiment the vertical buckling grooves 151, 152 are spaced apart on the front half of the energy absorbing curved beam 164, and the vertical buckling groove 153 is provided on the rear half of the energy absorbing curved beam 164. In this embodiment, one of the vertical buckling groves 151 may be milled about 60 - 65 cm, but preferably 63 cm, from the front end of the beam 164, a second grove 152 may be milled about 120 - 125 cm, but preferably 123 cm, from the front end of the beam 164, and a third groove 153 may be milled about 360-380 cm, but preferably 370 cm, from the front end of the beam 164.

[0087] FIG. 3C is a second side view of the energy absorbing curved beam 164, i.e. as it appears from the outside when it is arranged as part of the impact attenuator 100. The beam 164 is provided with screw holes 171, 173 for the attachment to the bracket 110b of the rear end frame 110 and the bracket 105b of the front end frame 105, respectively, and screw holes 172 for the attachment of the anchor plate 144 for the metal rods 140, 142, as illustrated in FIG 1. FIG. 3D is an enlarged cross sectional view of the energy absorbing curved beam 164 along the line IIID-IIID in FIG 3 A. In this embodiment, the energy absorbing curved beam 164 has a cross-sectional dimension of about, but not limited to, at least 15x10 cm (height x width).

[0088] Since all of the arc-shaped front elements 181-183 of the energy absorbing arc-shaped front module 125 may be identical, only one of the elements, i.e. element 181, is described herein with reference to FIGs. 4A-4C.

[0089] FIG. 4A is a side view of the arc-shaped front element 181. Advantageously, the arc-shaped front element 181 is provided with a plurality of circumferential reinforcement flanges 190. The height of the arc-shaped front element 181 may be about 10 - 20 cm, but preferably 15 cm. The flanges 190 may protrude horizontally about 2 -

[0090] 4 cm, but preferably 3 cm.

[0091] With reference to FIG. 4B, the arc-shaped front element 181 of the arc-shaped front module 125 form a circular arc of about 240°-280°, but preferably 260°, between the end points 126, 127 of the arc-shaped front module 125 having a bending radius of 5.2 - 5.7 m, but preferably 5.5 m. The thickness of the material may be 0.8-1.5 cm, but preferably 1 cm.

[0092] FIG. 4C shows a cross sectional view along the line IVC-IVC in FIG. 4B of the arc-shaped front element 181.

[0093] Since all of the arc-shaped front elements 184-186 of the energy absorbing arc-shaped rear module 130 may be identical, only one of the elements, i.e. element 184, is described herein with reference to FIGs. 5A-5C.

[0094] FIG. 5 A is a side view of the arc-shaped rear element 184. Advantageously, the arc-shaped front element 181 is provided with a plurality of circumferential reinforcement flanges 195. The height of the arc-shaped rear element 184 may be about 10 - 20 cm, but preferably 16 cm. The flanges 195 may protrude horizontally about 3 -

[0095] 5 cm, but preferably 4 cm.

[0096] With reference to FIG. 5B, the arc-shaped rear element 184 of the arc-shaped rear module 130 form a circular arc of about 240°-280°, but preferably 263°, between the end points 126, 127 of the arc-shaped rear module 130 having a bending radius of 5.7 - 6.2 m, but preferably 5.9 m. The thickness of the material may be 0.8-1.5 cm, but preferably 1 cm.

[0097] FIG. 5C is a cross sectional view along the line VC-VC in FIG. 5A.

[0098] Advantageously, the elongated first curved side wall 115 with the elongated curved beams 161-163, the elongated second curved side wall 120 with the elongated curved beams 164-164, the arc-shaped front module 125 with the arc-shaped front elements 181-183, and the arc-shaped rear module 130 with the arc-shaped rear elements 184-185 are made of aluminium alloy 6063-T4 and manufactured as extruded aluminum profiles in this embodiment. However, any other aluminium alloy with similar properties as 6063-T4 may be applicable.

[0099] Advantageously, the rear end frame 110, the brackets for attachment of the energy absorbing module 128 and the brackets 128a, 128b for attachment of the arcshaped front module 125 including the arc-shaped front elements 181-183, and the arcshaped rear module 130 including the arc-shaped rear elements 184-186 are made of aluminium alloy 6082-T6 and manufactured as extruded aluminum profiles in this embodiment. However, any other aluminium alloy with similar properties as 6082-T6 may be applicable.

[0100] Advantageously, the metal rods 135, 135’- 142, 142’ are made of stainless steel 316L in this embodiment. The rods may have a diameter of 7-12 mm, but preferably 9 mm. However, any other stainless steel with similar properties as 316L may be applicable.

[0101] The elongated curved beams 161-166 are arranged to be deformed when an errant vehicle crashes into the impact attenuator 100.

[0102] As illustrated in FIGs. 1 to 5, relative positions and dimensions of the components of the impact attenuator as well as the particular materials, such as aluminum alloys and stainless steel, described above provide an impact attenuator, which is inexpensive and light and meets the requirements of the MASH (Manual for Assessing Safety Hardware) guideline, in order to meet the requirements including the following tests: 3-50, 3-51, 3-52, 3-53, and 3-54.

[0103] The crossed metal rods 135, 135’, 136, 136’, 137, 137’, 138, 138’ are arranged to maintain the correct shape of the arc-shaped front module 125 and the arc-shaped rear module 130 in different types of collisions. In the event of a collision, tensile forces are created in the fifth - eight pairs of metal rods 139, 139’ - 142,142’ in the middle of the impact attenuator 100. Thereby, at least parts of the energy is absorbed by the impact attenuator 100 during a collision as one or more of the fifth-eight pairs of metal rods 139, 139’ - 142, 142’are pulled until breaking. Moreover, the fifth-eight pairs of metal rods 139, 139’ - 142, 142’ control the buckling points of the beams 161-166.

[0104] The inventor has realized that advantageous properties of the stainless steel, particularly the stainless steel 316L, are advantageous for this purpose as it is very tough and plasticizes over its entire length before breaking. In this embodiment, the entire elongation of the stainless steel may be utilized. However, any other stainless steel with similar properties to stainless steel 316L may be applicable.

[0105] The energy-absorbing parts of the device are thus preferably made of aluminum alloys and stainless steel. The device is designed to pass the tests described in the MASH standard, i.e. 3-50, 3-51, 3-52, 3-53 och 3-54. These tests include three centered collisions with vehicles weighing 1100 kg, 1500 kg and 2270 kg at a speed of 100 km / h as well as two tests with the heavier vehicle, including an offset collision and an angled offset collision.

[0106] The elongated curved beams 161-166 of the arc-shaped curved first and second side walls 115, 120 forming energy absorbing profiles arranged to absorb a maximum force according to the MASH standard requirements at a first phase of a collision during an initial time period. The standard requires that only a certain amount of force be absorbed for a certain amount of time at the beginning of the collision to give the driver of the colliding vehicle time to contact the steering wheel. In order to achieve that, the elongated curved beams 161-166 are arranged to bend and the metal rods 139, 139’ - 142, 142’ are extended up to about 1.5 times the original length of the metal rods before they break. Further, the metal rods 139, 139’ - 142, 142’are arranged to control the deformation of the elongated curved beams 161-166 and that the beams will break at the vertical buckling grooves during the collision.

[0107] During a second phase of the collision, the arc-shaped rear module 130 is arranged to absorb the energy caused by a vehicle weighing no more than 1100 kg. When the arc-shaped rear module 130 is essentially compressed, the second phase of the collision is completed.

[0108] In a third phase, the arc-shaped rear module 130 is forced forward and meets the arc-shaped front module 125 through the intermediate energy absorbing module 128. The honeycomb structure of the energy absorbing module 128 secures that the energy absorption takes place gradually, thereby preventing spike energy through the errant vehicle running into the impact attenuator 100.

[0109] If the vehicle running into the impact attenuator 100 is weighing no more than 1500 kg, the arc-shaped front module 125 will also be partly compressed before the collision is ended.

[0110] If the vehicle running into the impact attenuator 100 is weighing up to 2700 kg, the impact attenuator will be completely compressed, i.e. even the arc-shaped front module 125 will be completely compressed before the collision is ended. Although embodiments of the impact attenuator have been illustrated in the accompanying drawings and described in the foregoing detailed description, the disclosure is illustrative only, and changes, modifications and substitutions may be made without departing from the scope of the technology as set forth and defined by the following claims. Hence, it should be understood that the limitations of the described embodiments are merely for illustrative purpose and by no means limiting. Instead, the scope of the teaching is defined by the appended claims rather than by the description, and all variations that fall within the range of the claims are intended to be embraced therein.

[0111] According to the embodiments described herein, the metal rods are arranged in pairs of metal rods. However, in alternative embodiments, single metal rods or triple metal rods may be used instead of pairs of metal rods. Moreover, the metal rods may be either partly or fully threaded.

[0112] Moreover, the energy absorbing module may be attached to the envelope surface of the arc-shaped rear module facing the front module in an alternative embodiment.

[0113] In alternative embodiments, the arc-shaped front module and the arc-shaped rear module may comprise one, two, four or more arc-shaped front and rear elements, respectively.

[0114] In an alternative embodiment, each of the elongated first and second curved side walls may comprise one, two, four or more elongated curved beams. However, in an embodiment of an impact attenuator having elongated curved side walls with one or two beams of each side wall, the beams have larger cross-sectional dimensions and / or thicker material. In an embodiment of an impact attenuator having elongated curved side walls with more than three elongated curved beams of each side wall, the beams may have smaller cross-sectional dimensions and / or thicker material.

[0115] In addition, singular references do not exclude a plurality. The terms "a", "an", "first", "second" etc. do not preclude a plurality. Reference signs in the claims are provided merely as a clarifying example and shall not be construed as limiting the scope of the claims in any way. List of feature elements: impact attenuator 100 front end frame 105 rear end frame 110, a truck mounting arrangement 112 elongated first curved side wall 115, elongated second curved side wall 120, beam brackets 105a, 105b; 110a, 110b an elongated frame 121, arc-shaped front module 125 end points 126, 127 of the arc-shaped front module 125 energy absorbing module 128, arc-shaped rear module 130, end points 131, 132 of the arc-shaped rear module 130, brackets 126a, 127a, 128a, 128b, 131a, 132a first metal rod 135 second metal rod 136 third metal rod 137 fourth meatal rod 138 fifth metal rod 139 sixth metal rod 140 seventh metal rod 141 eight metal rod 142 anchor plates 143, 144 vertical buckling grooves 151-153 elongated curved beams 161-163; 164-166 screw holes 171-173 arc-shaped front elements 181-183 arc-shaped rear elements 184-186 circumferential reinforcement flanges 190, 195

Claims

CLAIMS1. An impact attenuator (100) for attachment to a host vehicle, comprising: a front end frame (105) and a rear end frame (110), an elongated first curved side wall (115) and an elongated second curved side wall (120) attached to the front end frame (105) and the rear end frame (110), wherein the front end frame (105), the rear end frame (110), the first curved side wall (115), and the second curved side wall (120) form an elongated frame (121), surrounding an open area, an arc-shaped front module (125) arranged within said open area and attached to the front end frame (105), an arc-shaped rear module (130) arranged within said open area and attached to the rear end frame (110), an energy absorbing module (128) arranged within the open area between the arc-shaped front module (125) and the arc-shaped rear module (130), crossed first and second metal rods (135,136) attached to the front end frame (105) at respective endpoints (126, 127) of the arc-shaped front module (125) and to opposite points on the inside of the arc-shaped front module (125), crossed third and fourth metal rods (137, 138) attached to the rear end frame (110) between endpoints (131, 132) of the arc-shaped rear module (130) and to opposite points on the inside of the rear module (130), a fifth metal rod (139) attached to the middle (143) of the elongated first curved side wall (115) and to a first point on an envelope surface of the arc-shaped front module (125), a sixth metal rod (140) attached to the middle (144) of the elongated second curved side wall (120) and to a second point on the envelope surface of the arc-shaped front module (125), a seventh metal rod (141) attached to the middle (143) of the elongated first curved side wall (115) and to a first point of an envelope surface of the arc-shaped rear module (130), and an eight metal rod (142) attached to the middle (144) of the elongated second curved side wall (120) and to a second point on the envelope surface of the arc-shaped rear module (130).

2. The impact attenuator (100) according to claim 1, wherein the energy absorbing module (128) is attached to the envelope surface of the arc-shaped front module (125) facing the rear module (130).

3. The impact attenuator (100) according to claim 2, wherein the front module (125) including the energy absorbing module (128) is arranged at a distance from the rear module (130).

4. The impact attenuator (100) according to any of the claims 1-3, wherein the crossed first and second metal rods and the crossed third and fourth metal rods comprises one or more pairs of crossed first and second metal rods (135, 135 ’ ; 136, 136’) and one or more pairs of crossed third and fourth metal rods (137, 137’; 138, 138’).

5. The impact attenuator (100) according to any of the claims 1-4, wherein the fifth, sixth, seventh, and eight metal rods comprises one or more pairs of the fifth, sixth, seventh, and eight metal rods (139, 139’; 140, 140’; 141, 141’; 142, 142’).

6. The impact attenuator (100) according to any of the preceding claims, wherein each of the elongated first and second curved side walls (115, 120) are attached to brackets (105a, 105b) of the front end frame (105) and brackets (110a, 110b) of the of the rear end frame (110), respectively.

7. The impact attenuator (100) according to any of the preceding claims, wherein each of the elongated first and second curved side walls (115, 120) is provided with vertical buckling grooves (151-153) spaced apart on the inside of the respective side wall (115, 120).

8. The impact attenuator (100) according to claim 7, wherein two of the vertical buckling grooves (151, 152) are spaced apart on a front half of each of the elongated first and second curved side walls (115, 120), and one vertical buckling groove (153) on a rear half of each of the elongated first and second curved side walls (115, 120).

9. The impact attenuator (100) according to any of the preceding claims, wherein each of the elongated first and second curved side walls (115, 120) comprises three elongated curved beams (161-163; 164-166) arranged on top of each other.

10. The impact attenuator (100) according to any of the preceding claims, wherein the arc-shaped front module (125) comprises three arc-shaped front elements (181-183) arranged on top of each other, and the arc-shaped rear module (130) comprises three arc-shaped rear elements (184-186) arranged on top of each other.

11. The impact attenuator (100) according to any of the preceding claims, wherein the arc-shaped front module (125) forming a circular arc of about 240°-280° between the end points (126, 127) of the arc-shaped front module (125).

12. The impact attenuator (100) according to any of the preceding claims, wherein the arc-shaped rear module (130) forming a circular arc of about 240°-280° between the end points (131, 132) of the arc-shaped rear module (130).

13. The impact attenuator (100) according to any of the preceding claims, wherein the energy absorbing module (128) has an aluminium honeycomb core.

14. The impact attenuator (100) according to any of the preceding claims, comprising a truck mounting arrangement (112) for attachment of the impact attenuator (100) to the host vehicle, wherein the front end frame (105) is attached to the truck mounting arrangement (112), thereby forming a cantilever impact attenuator.

15. The impact attenuator (100) according to any of the preceding claims, wherein the elongated first curved side wall (115), the elongated second curved side wall (120), the arc-shaped front module (125), and the arc-shaped rear module (130) are made of a first aluminium alloy.

16. The impact attenuator (100) according to claim 15, wherein the first aluminium alloy is aluminium 6063-T4, or any other aluminium alloy with similar properties.

17. The impact attenuator (100) according to any of the preceding claims, wherein the rear end frame (110), brackets (128a, 128b) for attachment of the energy absorbing module (128) and brackets (126a, 127a; 131a, 132a) for attachment of the arc-shaped front module (125) and the arc-shaped rear module (130) are made of a second aluminium alloy.

18. The impact attenuator (100) according to claim 17, wherein the second aluminium alloy is aluminium 6082-T6, or any other aluminium alloy with similar properties.

19. The impact attenuator (100) according to any of the preceding claims, wherein the metal rods (135-142; 135 ’ - 142’) are made of stainless steel.

20. The impact attenuator (100) according to claim 19, wherein the stainless steel is 316L, or any other stainless steel with similar properties.

21. The impact attenuator (100) according to any of the preceding claims, wherein the impact attenuator (100) is a Truck Mounted Attenuator, TMA.

22. The impact attenuator (100) according to any of the preceding claims, wherein the impact attenuator (100) is a trailer mounted attenuator comprising a trailer frame, a wheel set, and a trailer coupler for connection to the host vehicle.

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