ENERGY

DESCRIPTION

TECHNICAL FIELD

The present invention relates to energy absorbing apparatus, in particular for absorbing kinetic energy of impacts.

BACKGROUND ART

There are known rotaratable kinetic energy absorbers, in other words energy absorbing barriers, for converting kinetic energy of impact imparted to a translationally movable impact receiving element via a coupling arrangement to a rotor. A US patent application US20070007780 describes a kinetic energy absorber for connecting to a bumper of a car and comprising a rotatable energy absorber with a rotor connected with the bumper via a toothed bar and a toothed gear. Upon impact directed to the bumper, the translational motion of the bumper induces translational motion of the toothed bar, which induces rotation of the rotor. Such barriers provide dynamic absorption of kinetic energy.

Absorbers of this type can be used to as impact-receiving means in road barriers, as disclosed in European patent application EP10461530 or a PCT application PCT/EP201 1/053347, railway wagon buffers, as disclosed in European patent application EP1 1460002, or quay protection arrangements as disclosed in European patent application EP1 1460003.

The absorbers described in the above-mentioned documents comprise an arrangement with one or more rotors coupled with one or more actuators, all mounted in a single casing, therefore forming a single absorber.

DISCLOSURE OF THE INVENTION The aim of the present invention is to provide an energy absorbing apparatus with improved energy absorbing capacity.

The object of the invention is an energy absorbing barrier, comprising a plurality of energy absorbing modules , each module comprising a casing configured to receive impact energy and a rotor mounted within the casing and coupled via coupling means with an actuator , the casing being movable with respect to the actuator such as to absorb at least part of the kinetic energy of impact imparted to the casing in rotational movement of the rotor . The modules being arranged in at least two serially connected sections, wherein the casing of at least one module in each section is movable with respect to the casing of at least one module in the preceding section and configured to receive the impact energy not absorbed by the module of the preceding section.

The barrier may further comprise supplementary absorbers mounted between the casings of modules of successive sections.

The barrier may further comprise supplementary absorbers mounted between the casings of modules of at least the last section and the object to be protected from impact.

The energy absorbing capacity of each successive section can be higher than the energy absorbing capacity of its preceding section.

Each successive section may comprise more energy absorbing modules than its preceding section.

Each successive section may comprise modules of higher energy absorbing capacity than the modules of its preceding section.

At least one section of modules may comprise a plurality of modules connected in parallel.

At least one module may comprise a plurality of rotors, each mounted within the casing and coupled via individual coupling means with an individual actuator.

At least some of the modules can be mounted movably on a common base to which the actuators for the movable modules are fixed still.

At least some of the modules can be fixed still on a common base and comprise movable actuators mounted within the casing of the module . BRIEF DECRIPTION OF DRAWINGS

The present invention is shown by means of exemplary embodiments on a drawing, in which:

Fig.1 shows a general schematic of an energy absorbing module.

Figs. 2A-2C show a general schematic of an energy absorbing barrier before impact, during impact and after impact.

Figs. 3A-3B present a first exemplary embodiment of the barrier in a pre- impact and post-impact position.

Fig.4 presents a second exemplary embodiment of the barrier.

Fig.5 presents a third exemplary embodiment of the barrier.

Fig.6 presents a fourth exemplary embodiment of the barrier.

MODES FOR CARRYING OUT THE INVENTION

Fig. 1 shows a general schematic of an energy absorbing module 100, operating according in line with the principles of the rotatable kinetic energy absorbers known from the prior art as described above. The module comprises a casing 101 configured to receive impact energy, for example via a bumper 106. The bumper 106 may comprise compressible elements, such as to dampen the first section of the impact. The casing 101 may be a full housing with walls, floor and ceiling surrounding and protecting the internal components from external environment, or a frame configured to provide only support for the internal components. A rotor 102 is mounted within the casing 101 , for example via a shaft 105 fixed to the sides of the casing 101 , and coupled via coupling means 104 with an actuator 103. The casing 101 , together with the rotor 102, is movable with respect to the actuator 103 such that at least part of the impact energy imparted to the casing 101 is absorbed in rotational movement of the rotor 102. The amount of energy accumulated in the rotor 102, in other words a rotatable mass, depends on the weight and the moment of inertia of the rotor, its diameter and rotational speed, which in turn depends on the parameters of the transmission between the actuator 103 and the rotor 102. Preferably, the rotor 102 is a freewheel. The actuator 103 can be a toothed bar and the coupling means 104 can be a toothed wheel, forming a rack and pinion mechanism, and the coupling means 104 may comprise a plurality of toothed gears engaging with a toothed wheel of the rotor 102 so as to form a transmission multiplying the rotational speed. Alternatively, the coupling means 104 may have a form of a strand having one end connected to the actuator 103 in form of a strand holder and the other end wound around a shaft of the rotor 102.

Figs. 2A-2C show a general schematic of an energy absorbing barrier according to the invention before impact, during impact and after impact, respectively. The barrier has a base 230 on which a plurality of energy absorbing modules 21 1 -217 are mounted, each having a structure as discussed with respect to Fig.1 . The base 230 may be fixed to a object 231 to be protected from impact. The modules 21 1 -217 are arranged in at least two serially connected sections. In the embodiment of Figs. 2A-2C three sections are present, namely a first section comprising the module 21 1 , a second section comprising parallel modules 212, 213 and a third section comprising parallel modules 214-217. The casing of at least one module in each section is movable with respect to the casing of at least one module in the preceding section and configured to receive the impact energy not absorbed by the module of the preceding section. For example, the casings of the modules 21 1 - 217 may be movable along guides 221 -227 running along the energy absorption direction. The actuators with which the rotors of the modules are coupled in the configuration before impact are preferably fixed still to the base 230.

The barrier operates as follows. When impact is applied to the module 21 1 of the first section, the casing of the module 21 1 starts to move along the guide 221. The relative motion between the actuator and the casing induces, via its coupling means, rotation of the rotor of the module 21 1 , in which at least part of the kinetic energy of the impact is absorbed. In case the impact energy is lower than the energy absorption capabilities of the first module 21 1 , the whole impact energy is absorbed and the barrier stops in a position such as shown in Fig.2B. In case the impact energy is higher than the energy absorption capabilities of the first module, the first module 21 1 continues its movement and hits the second section comprising modules 212, 213. The kinetic energy of impact not accumulated by the first section is passed to the casings of the modules 212, 213 of the second section, which start to move along guides 222, 223. The relative motion between the actuators and the casings induces, via their coupling means, rotation of the rotors of the modules 212, 213, in which at least part of the remaining kinetic energy of the impact is absorbed. In case the whole impact energy is not absorbed, the remaining energy is passed to the third section with modules 214-217. In case the remaining impact energy is lower than the energy absorption capabilities of the third section, the remaining energy is absorbed in rotary motion of the rotors of the third section modules 214-217 and the barrier stops in arrangement as shown in Fig.2C, and the object 231 is effectively protected from impact. In case of impacts of energy larger than the total absorption capacity of the modules 21 1 -217 of all sections, only part of impact energy is imparted to the protected object 231 .

Supplementary absorbers 242-245 can be provided between the casings of modules 21 1 -217 of successive sections in order to partially damp the impact transmitted between the casings. The supplementary absorbers 242-245 may have the form of springs and/or pneumatic, hydraulic or magnetic dampers. Alternatively, the supplementary absorbers 242-245 may have the form of rotary kinetic energy absorbers with absorption capabilities lower than that of the modules 21 1 -217.

In addition, supplementary absorbers 246-247 can be provided between the casings of at least the modules 214-217 of the last section and the protected object 231 , in order to at least partially absorb the energy not absorbed by the modules 21 1 - 217 and damp the final impact transmitted to the protected object 231 .

Preferably, the energy absorbing capacity of each successive section of modules 212-213; 214-217 is higher than the energy absorbing capacity of its preceding section 21 1 ; 212-213. In this manner, the barrier can be configured to receive a wide range of impacts. This can be achieved by increasing the number of modules in each successive section, as shown in figs. 2A-2C and 3A-3B. Moreover, this can be achieved by increasing the energy absorbing capacity of individual modules in each successive section, for example by increasing the energy accumulation properties of rotors as shown in Fig.5 or the number of rotors in each module, as shown in Fig 6.

Figs. 3A-3B present a first exemplary embodiment of the barrier in a pre- impact and post-impact position. The barrier comprises three modules 31 1 -313, the module 31 1 forming the first section and the modules 312, 313 forming the second section connected in series to the first section. For each module 31 1 -313 there is provided an actuator 303 in form of a toothed bar fixed to the base 330. Each module 31 1 -313 comprises a casing 301 and a rotor 302 mounted within the casing 301 on a support 305 fixed to the casing 301. The coupling between the rotor 302 and the actuator 303 has the form of a transmission formed by toothed gear sections 304. The casing 301 is movable with respect to the base 330, i.e. with respect to the actuators 303. When impact is imparted to the first module 31 1 , its casing 301 moves towards the second section of modules 312, 313 and the toothed gear 304 engaged with the toothed bar 303 induces rotation of the rotor 302. At least part of the kinetic energy of the impact is accumulated in the rotor 302. In case the whole impact energy is not accumulated, as the first module 31 1 moves, protrusions 307 in its casing 301 contact the casings of the modules 312, 313 of the following section, thereby passing the energy not accumulated to the casings of modules of the following section. In the post-impact configuration shown in Fig.3B, the casings are moved in the direction of absorbed impact and at least part of the impact energy is absorbed.

Fig.4 presents a second exemplary embodiment of the barrier. The barrier comprises three modules 41 1 -413, each forming an individual section connected in series with neighboring sections. The modules 41 1 , 412 have actuators of the type indicated by reference 403A, in form of a toothed bar fixed to the base 430. The module 413 has actuators of the type indicated by reference 403B, in form of a toothed bar mounted movably within the casing of the module 413 which is fixed still to the base 430. Modules 41 1 , 412 are mounted movably with respect to the base 430. Each of the modules 412, 413 comprises a plurality of rotors. The casings of modules 41 1 , 412 are configured to move inside the casings of the following modules 412, 413. Upon impact received by the front wall 407 of the first module 41 1 , the casing of the first module moves with respect to the base and the actuator, thereby causing rotation of the rotor of the first module and accumulation of at least part of the impact energy. After the casing of the first module 41 1 moves inside the casing of the second module 412, the front wall 407 causes further movement of the first module 41 1 and the second module 412, thereby causing rotation of the rotors of the second module 412 and accumulation of at least part of the remaining energy therein. In case the whole energy is not accumulated, the casings of the first module 41 1 and of the second module 412 move inside the casing of the third module 413 and protrusions 408 at the front wall 407 cause movement of the actuators 403B, thereby inducing rotation of the rotors of the third module 413.

Fig.5 presents a third exemplary embodiment of the barrier. The third embodiment has a structure equivalent to that shown in Fig.4. The size of rotors 521 , 522, 523 increases for successive modules 51 1 , 512, 513, therefore increasing energy accumulation capabilities in successive sections.

Fig. 6 presents a fourth exemplary embodiment of the barrier. The fourth embodiment has a structure equivalent to that shown in Fig.4. The number of rotors in successive modules 61 1 , 612, 613 increases, for example exponentially.

By connecting the energy absorbing modules in series, the energy of impact can be efficiently absorbed. It follows from the principles of operation of the rotatable kinetic energy absorbers, that a single absorber is capable of absorbing a specific fraction, such as e.g. 50%, of the energy of impact applied to it. Therefore, by connecting the modules having efficiency of 50% in series, the energy of impact can be absorbed in 50% at the first section, in 75% at the second section, in 87,5% at the third section, in 93,75% at the fourth section etc. This energy absorption capabilities can be further increased by using conventional absorbers, such as springs or dampers, to absorb a given amount of the remaining energy not accumulated at the given section.