Patent Description:
There exist many situations where a load may cause damages upon sudden deceleration or vice versa that sudden deceleration causes damages on the load, e.g. when a vehicle is crashing. Due to the high energy that has been gained by the load due to the speed sudden deceleration may cause attachment members between the vehicle and the assembly carrying the load to break, e.g. disrupt, which may cause severe damages. One typical example that may be referred to is a car having a roof box carried on top of a roof rack.

Severe disasters have been caused by heavy loads on roof racks that in connection with sudden deceleration of vehicles, e.g. crash, have loosened from their attachments to the roof rack. For instance, roof boxes have been causing disasters in this manner. As is well known, roof boxes may enclose a very large volume and accordingly it is possible to put a lot of load into a roof box. In connection with a crash, or other sudden deceleration, there is a risk that the attachment members keeping the roof box in place on the roof rack may be over-strained and rupture. In such a situation the roof box will continue to travel at high speeds along an uncontrolled trajectory, thereby risking to destroy and/or injure objects and/or people within that trajectory.

From <CIT> there is known an arrangement intended to minimize the above risk, which is based on a specifically designed attachment between a holder of a roof rack and a bracket attached onto the roof of the vehicle. However, such an arrangement does not eliminate or reduce the risk that at large impact the attachment devices keeping the load e.g. roof box, onto the roof rack may rupture.

From <CIT> and <CIT> it is known to supplement a roof rack assembly with energy absorbing devices in order to reduce hazard upon sudden deceleration. However, these designs present some essential disadvantages. One major disadvantage is that the energy absorbing device is complicated to install and is of need of specifically designed inter-fitting details. Further, from <CIT> it is known to supplement a trailer hitch with an energy absorbing member, which presents some essential disadvantages, e.g. providing a relatively limited energy absorption and having a relatively bulky and complex design.

Further, from <CIT>, <CIT> and <CIT> there are known safety devices intended to be used by people working high up, e.g. on roofs, including energy absorbing members, where <CIT> discloses an energy absorbing member according to the preamble of claim <NUM>.

It is an object of the invention to eliminate or at least reduce the above-mentioned problem which is achieved in accordance with a solution as defined in claim <NUM>.

Thanks to the invention there is provided an energy absorbing means for a load carrying, load pulling, load pushing or load stopping assembly, or the like, which may eliminate disastrous consequences in connection with sudden decelerations, e.g. crashes, and which may easily be used in a flexible manner in various applications and easily maintained and exchanged.

In one application it may relate to a load carrying assembly on a vehicle carrying a load in the form of a roof box, or similar device, which will absorb energy in a controlled manner at impact which in turn will decrease the strain excerpted on, or applied to, the attachment devices between the load and the vehicle. Accordingly, the risk of rupture of any attachment device is thereby significantly reduced, which may save lives and eliminate or decrease possible damages.

In another application it may relate to a security arrangement for a load pulling assembly connected to a vehicle, wherein a security arrangement including an energy absorbing member according to the invention may eliminate a rupture of the coupling between the load pulling vehicle and the load that is pulled, e.g. in the form of a trailer and a vehicle arranged with a tow bar.

In another application according to the invention it may relate to a vehicle pushing a load wherein a security arrangement with an energy absorbing member according to the invention may eliminate rupture between a coupling between the pushing vehicle and the pushed load, e.g. a train pushing a wagon.

In another application it may relate to a vehicle in the form of a moveable device in a machine which is arranged with a load stop assembly, wherein security arrangement including an energy absorbing member according to the invention may eliminate rupture of the attachment between the ground and the stop member of the machine.

The basic principle of the solution according to the invention includes the use of an energy absorbing member including a stabilizing control arrangement, such that it will not allow any substantial relative movement between the attachment devices, i.e. at a force below a predetermined level. At a force above said predetermined level the stabilizing control arrangement will rupture and thereafter a soft deceleration is achieved by means of the energy absorbing member deforming, i.e. by being elongated, and wherein at least a portion of the energy will be transformed to permanent deformation of said energy absorbing member. In a preferred embodiment the energy absorbing member is made of a ductile material, e.g. a shaped body of metal to enable deformation parallelly with the longitudinal direction, i.e. enable prolongation in said longitudinal direction according to some examples.

Preferably the energy absorbing member may easily be replaced by a new member after having been elongated.

According to further aspects of the invention:.

Further aspects and details of the invention will become apparent from the following detailed description.

In the following the invention will be described in more detail with reference to the enclosed figures, wherein;.

In <FIG> there is shown a schematic view of a vehicle <NUM> with a roof rack carrying a roof box <NUM>, where four exemplary security arrangements A are arranged, and wherein each security arrangement A may have an energy absorbing member <NUM> according to the invention. In the shown example the security arrangements A are arranged between the roof box <NUM> and the roof rack, i.e. two on the front roof rack bar and two on the rear roof rack bar, forming a load carrying assembly <NUM>. It is foreseen that instead of two, merely one single unit may be used at the front and rear, respectively and indeed even merely one single unit for all of it. Such exemplary security arrangements A are adapted to secure e.g. a roof box <NUM> to e.g. a roof rack, forming a load carrying assembly <NUM>.

Generally, this kind of exemplary security arrangement A may be seen as an attachment arrangement A for attaching a device for carrying a load, e.g. a vehicle <NUM>, e.g. attached to the roof or part of the roof of such a vehicle <NUM>, e.g. a roof rack attached to roof rails of the vehicle, wherein the security arrangement A is arranged between roof rack and a load <NUM> carried by the roof rack. However, it may also fulfil the same basic function in other applications, as will become evident below. Hence, the above description, wherein an example is given, is merely intended to make it easier to understand how the basic function of invention may be used to achieve improved safety. The core of this invention relates to an improved design of an energy absorbing member <NUM> that may be used in the above described exemplary application.

The energy absorbing member <NUM> includes a shaped body <NUM>, including a plurality of U-shaped portions 35A -35D connected to each other in a row forming the shaped body <NUM>, wherein two neighbouring U-shaped portions 35A, 35B, etc will form an S. Hence, every second U-shaped portion 35A, 35C of a first kind have the curve part on a first side of a longitudinal centre line C and every second U-shaped portion 35B, 35D of a second kind have the curve part on a second side of a longitudinal centre line C. Preferably, the body <NUM> of the energy absorbing member <NUM> is flat shaped, which provides the advantage that it may be included in an assembly in a compact/hidden manner. Further it also provides the advantage that it may easily be produced by means of cutting or punching from a plate material, e.g. a metal plate.

When a sufficiently large force F1 is applied in the longitudinal direction the shaped body <NUM> will be straightened and elongated, and at least partially permanently deformed/prolonged, i.e. if the force exceeds a predetermined level. However, in the preferred embodiment the energy absorbing member <NUM>, will be designed to withstand substantially higher forces, without any rupture, once the shaped body <NUM> has absorbed energy that has totally straightened the body <NUM>, due to elastic and plastic deformation of the body <NUM> itself before rupture. Accordingly, a relatively soft deceleration will first be achieved during the straightening phase and thereafter a less soft deceleration will be achieved during the elastic and plastic deformation of the body <NUM> itself.

Preferably the shape of the energy absorbing member <NUM> is such that the relative movement may only reach a maximal prolongation ΔLmax %= <NUM> x (Lmax- L<NUM>) / L<NUM>) of said absorbing member <NUM> from its nominal length L<NUM>, (e.g. <NUM>-<NUM>) to a maximum length Lmax, wherein ΔLmax is at least <NUM>%, preferably at least <NUM>%, more preferred at least <NUM>%, i.e. in some applications up to <NUM>% or more. In many applications the meandering/multi-S shaped energy absorbing body <NUM> may preferably be prolonged from a nominal length L<NUM> to a maximal prolongation ΔLmax within a range of about <NUM> - <NUM> %, e.g. if of about <NUM> i.e. a maximum length Lmax of about <NUM> -<NUM>.

In a modified embodiment (not shown) the meandering/multi-S shaped energy absorbing member <NUM> may have a body <NUM> shaped to have an increasing energy absorbing effect during prolongation, e.g. by means of having a continuously increasing cross-sectional area of the body, e.g. by means of having an increasing width W1 from one end to the other, i.e. the curve part of the first U-shaped portion 35A may then have a width that is less than the width of a second and/or third U-shaped portion <NUM> B. As a result, it will require a first level of force F1 (e.g. above <NUM> N, or more preferred above <NUM> N) to straighten out the first bend/curve part having the smallest width, a higher a second level (e.g. + <NUM>-<NUM> %) of force F2 to straighten out the second bend/ curve part having a larger width, etc..

Further, as described in more detail below the shaped body <NUM> of the energy absorbing member <NUM> has a stabilizing control arrangement <NUM> including ribs <NUM> extending in the longitudinal direction, providing the advantage that during normal use (relatively low forces acting) of an assembly including a shaped body <NUM> according to the invention there will be no relative movement between the attachment points <NUM>, <NUM> of the energy absorbing member <NUM>, e.g. eliminating oscillations that may occur without the stabilizing control arrangement <NUM>.

The design of a rib <NUM> is such that the rupture force RF is substantially smaller than F1, preferably many times smaller than F1, whereby disturbing oscillations or movements that may cause disadvantages during normal use may be eliminated, but full function still is obtained regarding the main function of energy absorbing member <NUM>. The stabilizing control arrangement <NUM> will be of a material and have such a dimension that it breaks at a desired/predetermined level of force, where after the energy absorbing member <NUM> will start taking over the function to absorb energy. Preferably, the longitudinally extending ribs <NUM> are made of the same material as the shaped body <NUM>, e.g. cut or punched out from a flat piece of metal, whereby the largest cross sectional area AR of said longitudinally extending ribs <NUM> is substantially smaller than the smallest cross sectional area AS of the shaped body <NUM>, wherein preferably AS > <NUM> AR, more preferred AS > <NUM> AR, and wherein the areas AS, AR are proportional to the widths W2 and W3 respectively.

In <FIG> there is shown a view from above of a preferred embodiment of an energy absorbing member <NUM> according to the invention. The body <NUM> of the energy absorbing member <NUM> is preferably flat shaped and arranged between two attachment members <NUM>, <NUM>, preferably also flat shaped, e.g. in the form of plates <NUM>, <NUM>, with attachment passages <NUM>, <NUM>. There may be arranged two rows of parallelly extending body members <NUM>', <NUM>", which jointly will absorb energy as described above. Preferably, the two rows of parallelly extending body members <NUM>', <NUM>" are arranged mirror symmetric in relation to the longitudinal centre line C. Accordingly, each row <NUM>',<NUM>" will include a plurality of consecutive U-shaped portions 35A, 35B, etc..

Further, there is shown in <FIG> that there is arranged a stabilizing control arrangement <NUM>. The stabilizing control arrangement <NUM> as main feature comprises longitudinally extending ribs <NUM> providing basically the same kind of function as described above. The longitudinally extending ribs <NUM> extend the whole distance between the attachment parts <NUM>, <NUM> along the centre line C between the two body members <NUM>', <NUM>", preferably the longitudinally extending ribs <NUM> extend in between the two rows <NUM>', <NUM>'' without contacting any part of rows, i.e. without contact with any part of the most centrally positioned part 35i of any U-shaped portion 35A, 35B, but in a space formed between the two rows <NUM>', <NUM>".

Furthermore, there may also be provided transversally extending ribs <NUM>, to achieve further stability. Hence, the transversally extending ribs <NUM> may provide for increased stability during normal use, i.e. during use that does not exceed the force level (e.g. 700N) that will start to deform any of the ribs <NUM>, <NUM>. Together with the longitudinally extending ribs <NUM> the transversally extending ribs <NUM> will provide a stabilizing structure that may keep the energy absorbing body <NUM> form stable in regard to forces from any direction of the two dimension of extension of the flat shaped energy absorbing body <NUM>. The transversally extending ribs <NUM> may also assist in achieving improved control during energy absorption, i.e. a more controlled straight-lined elongation than if without such transversal ribs <NUM>. Each transversal rib <NUM>, as do also each longitudinal rib <NUM>, extends from a hub part <NUM>. There is a plurality of such hub parts <NUM> centrally positioned along the centre line C Each hub part <NUM> preferably presents a larger part, i.e. has a larger area seen from above than the ribs <NUM>, <NUM>. The thickness of the ribs <NUM>, <NUM> and the hub is preferably the same, and as a result the hub parts <NUM> will not rupture but instead the ribs <NUM> upon application of a force that exceeds the rupture level of the ribs <NUM>.

Preferably there is arranged a curved transition zone at the periphery of the hub <NUM> extending between each transversal rib <NUM> and longitudinal rib <NUM> to safeguard that the ribs <NUM>, <NUM> will rupture and not the hub part <NUM>. As a consequence, the width W4 of each hub part <NUM> will preferably be larger than the width W2, W3 of the ribs <NUM>, <NUM>. However, it is evident for the skilled person that basically the intended function may also be achieved by having the hub in various forms, e.g. to have the same width as the ribs, <NUM>, <NUM>, e.g. W4 = W3. The whole stabilizing control arrangement <NUM> extends substantially the same distance as each one of the energy absorbing body members <NUM>', <NUM>". Thanks to the arrangement a very stable and controlled function of the energy absorbing member <NUM> may be achieved. Firstly, the ribs <NUM>, <NUM> will safeguard that no movement will occur between the attachment parts <NUM>, <NUM> during normal use, i.e. when being used and not exceeding the predetermined rupture force level RF (e.g. 700N), i.e. a force level that cannot start to deform any of the ribs <NUM>, <NUM>. At exceeding such a level RF, firstly the longitudinal ribs <NUM> will break and thereafter the transversal ribs will be pushed together and bend and follow the hub portion <NUM>. Thanks to this arrangement there will be a very controlled elongation during the consecutive rupture of the ribs <NUM> of the stabilising control device <NUM> until a larger force is applied that will start to be absorbed by elongation of the absorbing body members <NUM>', <NUM>".

In <FIG> there is shown an energy absorbing member <NUM> that has been applied to a force exceeding the predetermined force level F1 where it starts to elongate. As can be noted the shaped body <NUM> has prolonged at least the double length compared to the original length of the shaped body. As a consequence, the two S-shaped rows <NUM>', <NUM>" have turned into more or less straight-lined rows. Further, it is shown that all the longitudinal ribs <NUM> have ruptured and left fragments <NUM>' of each longitudinal rib <NUM>. Moreover, the transversally extending ribs <NUM> have been bent by the pressing forces that have been applied during elongation. The hub-shaped parts <NUM> have been moved relative to each other but in other aspects remained more or less undeformed. As can be noted the elongation has been performed in a controlled straight-line manner, which in many applications is a major advantage.

In <FIG> there is shown a fourth embodiment of an energy absorbing member <NUM> according to the invention where there is use of the same kind of shaped body <NUM> as also shown in <FIG> and <FIG>. Herein also two rows <NUM>', <NUM>" of a plurality of U-shaped portions 35A, 35B etc. are used to form two parallel rows including a plurality of S-shaped parts. Also, here there is arranged a stabilization control device <NUM> comprising longitudinal ribs <NUM> and transversal ribs <NUM> which emanate centrally from the hub part <NUM>. Further, it is shown that the attachment devices <NUM>, <NUM>, as is an evident alternative, include both through holes <NUM>, <NUM> and shoulders <NUM>, <NUM> to fixedly position the energy absorbing member <NUM> within an arrangement.

In <FIG> there is shown in a perspective view providing a more detailed presentation of a preferred energy absorbing shaped body <NUM>, which is in substance is designed in the same manner as has been described above in relations to <FIG> and <FIG>. It is shown that preferably the thickness W of the plate material may be more or less the same as the width W1 of the shaped body parts <NUM>, preferably W < W1 ≤ <NUM>,<NUM> W.

In <FIG>, <FIG> it is shown that each transversal rib <NUM> has a substantial length l, i.e. a length l that is larger than the thickness W of the shaped body <NUM>. Preferably the length l of each transversal rib <NUM> is at least two times, preferably <NUM>-<NUM> times larger than the thickness W of the shaped body <NUM>. This is preferably achieved by having the outer end of each transversal rib <NUM> connected to a distal part 35d of each shaped body <NUM> in a configuration having two rows of parallelly extending mirror symmetric body members <NUM>', <NUM>". More preferred this is achieved by having the hub-shaped parts <NUM> positioned centrally in between distal parts 35d of two neighbouring mirror symmetric rows <NUM>', <NUM>", such that each pair of transversal ribs <NUM> having their inner ends connected to the hub part <NUM>, when extending substantially obliquely in relation to the centre line C, will have their outer ends connected to a distal part 35d of each shaped body <NUM>. Moreover, preferably the width W2, W3 of the ribs <NUM>, <NUM> is such that the width W2 of the transversal ribs <NUM> is within the range of <NUM>,<NUM>-<NUM> times the width W3 of the longitudinally extending ribs <NUM>, e.g. in some embodiments having the same or substantially the same width W2, W3 for both ribs <NUM>, <NUM>.

In a most preferred embodiment, the minimum radius R at the inner curved surface of the bends of each S-shaped part body part is in the range of W ≤ R ≤ <NUM>,5W. Further preferably the thickness W of the shaped body <NUM> may be within the range of 10W ≤ L<NUM> ≤ <NUM> W of the nominal length L<NUM> of the shaped body <NUM>, and the width W2, W3 of the ribs <NUM>, <NUM> within the range of <NUM>,<NUM> - <NUM>,<NUM> of the thickness W of the shaped body <NUM>.

It is foreseen that an energy absorbing member according to the invention may be used in a large variety of applications, e.g. different kind of security arrangements, e.g. for an assembly having a vehicle pushing a load wherein the security arrangement may eliminate rupture between a coupling between the pushing vehicle and the pushed load, e.g. a train pushing a wagon. In another exemplary application it may relate to a vehicle in the form of a moveable device in a machine which is arranged with a load stop assembly, wherein the security arrangement including such an energy absorbing member may eliminate rupture of the attachment between the ground and the stop member of the machine.

Claim 1:
Energy absorbing member (<NUM>) for a load carrying, load pulling, load pushing or load stopping assembly or the like, wherein said energy absorbing member (<NUM>) includes first and second attachment devices (<NUM>, <NUM>) and a shaped body member (<NUM>) extending in a longitudinal direction (C) between said first and second attachment devices (<NUM>, <NUM>), which shaped body member (<NUM>) when applied to a force above a first force level (F1) is arranged to enable a predetermined relative elongation (ΔL) between said first and second attachment devices (<NUM>, <NUM>) parallelly with said longitudinal direction (C) upon simultaneous absorption of energy reducing the risk of hazard in connection with sudden deceleration, wherein said absorbing member (<NUM>) includes a stabilizing control arrangement (<NUM>) that extends along said shaped body member (<NUM>) arranged to stabilize said shaped body member (<NUM>) in relation to forces not exceeding a first force level (F1) hindering relative movement between said attachment devices (<NUM>, <NUM>) in at least said longitudinal direction (C), and wherein said stabilizing control arrangement (<NUM>) includes at least one longitudinally extending rib (<NUM>),said longitudinally extending rib (<NUM>) extending along a centre line (C) between a neighbouring pair of rows of body members (<NUM>', <NUM>"), whereby there is a longitudinally extending row of longitudinal ribs (<NUM>) extending the whole distance between said attachment parts (<NUM>, <NUM>) characterized in that there is arranged a plurality of pairs of transversal ribs (<NUM>), connecting in between the longitudinal ribs (<NUM>) and two neighbouring rows (<NUM>', <NUM>") of said shaped body member (<NUM>), wherein each transversal rib (<NUM>) and each longitudinal rib (<NUM>) extend from a hub part (<NUM>) that is positioned along said centre line (C), and wherein there is arranged a plurality of hub parts (<NUM>) positioned along said centre line (C).