Energy absorbing system for absorbing energy of an object in a vehicle in a crash situation

An energy absorbing system that is adapted for absorbing energy of an object in a vehicle in a crash situation by decreasing acceleration and force acting on the object in the crash situation, the energy absorbing system comprising at least one plastically deformable energy absorber that is plastically deformable in the crash situation. A mass-dependent self-adjusting mechanism is provided, the mass-dependent self-adjusting mechanism being adapted for adjusting, on the basis of an underlying mass of the object, a required compensation force that is to be provided by the energy absorbing system in the crash situation for plastically deforming the at least one plastically deformable energy absorber in order to decrease the acceleration and force acting on the object.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to European patent application No. EP 15400032.7 filed on Jul. 22, 2015, the disclosure of which is incorporated in its entirety by reference herein.

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The invention is related to an energy absorbing system that is adapted for absorbing energy of an object in a vehicle in a crash situation by decreasing acceleration and force acting on said object in said crash situation. The invention is further related to a vehicle seat and to a vehicle having a seat provided with such an energy absorbing system.

(2) Description of Related Art

An Energy Absorbing System (EAS), which may also be referred to as an Energy Absorption/Attenuation System, is usually provided in a crashworthy seat of a vehicle, such as an aircraft, for protecting an occupant of the crashworthy seat e.g. in a crash situation of the vehicle by reducing an occurring body load. Currently, complex EAS exist that are automatically electronically adjustable, for instance by using magneto-rheological fluids. Furthermore, fixed-force EAS with multiple different functioning principles exist, which are generally cheaper and easier to manufacture.

The document US2002/0079725 describes an exemplary fixed-force EAS for absorbing energy of a vehicle or component of a vehicle or occupant of the vehicle in a crash situation so as to allow relatively gradual deceleration of the vehicle, component or occupant. This fixed-force EAS includes a first part, a second part and an elongate deformable member secured to the first part and extending through a deforming arrangement carried by the second part. The elongate deformable member normally acts as a tie or strut between the first and second parts, but the arrangement is such that, when the force acting between these first and second parts exceeds a predetermined amount in a predetermined direction, the elongate deformable member is forced progressively through the deforming arrangement as the distance between the first and second parts changes and the deformable member is thereby forced to undergo plastic deformation, whereby energy is absorbed. The deforming arrangement is such as to effect such plastic deformation substantially without changing the material cross sectional area of the deformable member.

More specifically, the fixed-force EAS according to the document US2002/0079725 is implemented as a roller-tube assembly, wherein the deforming arrangement is provided by means of a roller arrangement having rollers with fixed, i.e. predefined, distances relative to each other, and the deformable member is provided by means of a plastically deformable attenuation tube. In other words, energy absorption/attenuation is performed by deformation of the attenuation tube by means of the rollers with the predefined distances relative to each other.

However, by fixing the distances between the rollers of the roller arrangement to such predefined distances, the rollers may only transmit a predetermined compression force to the plastically deformable attenuation tube for plastically deforming the latter. Consequently, this system can only be manually and stepwise adjusted by adding and connecting additional roller-tube assemblies.

The document US2002/0079725 further describes that manual or automatic adjustment of the energy absorbing characteristics of the described roller-tube assembly can be achieved in a number of ways, including:

(1) Adjustment of wall thickness by rotating, about its longitudinal axis, an attenuation tube having a circular cross-section exterior and a non-circular internal cross-section, to various positions within the roller arrangement, so as to vary the force required to flatten or deform the attenuation tube and hence to alter the attenuation characteristics.

(2) Partially pre-deforming, e. g. flattening, the attenuation tube varying amounts:(2.1) Rotation of an attenuation tube having a noncircular form of constant or varying wall thickness such that different parts of the periphery of the attenuation tube are presented to the rollers of the roller arrangement so that different forces are needed to deform the attenuation tube, thus providing adjustment for different occupants.(2.2) Varying a predefined gap between the rollers of the roller arrangement or equivalent parts of the respective deforming arrangement, thereby increasing or decreasing the force required to flatten/deform the attenuation tube.

(3) Varying the roller diameter via tapered cones. In a similar fashion to (2.2) above, the gap that the attenuation tube is required to pass through may be either increased or decreased by moving the rollers of the roller arrangement or other corresponding fixed members as appropriate to present the desired diameter to the attenuation tube, thus, changing the attenuation properties.

However, while the document US2002/0079725 describes that the energy absorbing characteristics of the described roller-tube assembly can be adjusted manually or automatically and further enumerates a number of ways how this can be achieved, it remains silent on concrete realizations. For instance, one described way consists in varying a predefined gap between the rollers of the roller arrangement for increasing or decreasing the force required to flatten/deform the attenuation tube. Nevertheless, it is not described how this variation is performed, whether it is performed manually or automatically, whether it is performed between different discrete predefined gap values and so on.

The document US2009/326765 describes load limiting on a seat belt buckle by providing an adjustable energy absorbing device mounting the seat belt buckle. Vehicle and occupant conditions are electronically sensed to determine the optimal adjustment of the adjustable energy absorbing device. The adjustable energy absorbing device is an extendable strut having an end connected to the buckle and an end connected to the vehicle. The strut has metal deforming elements to be deformed upon the load reaching a certain magnitude by ball shaped plow shoes.

The document US2009/322066 describes a load limiting device for mounting a seat belt buckle that also includes a plow shoe attached to one of the buckle and a pair of opposed plates attached to the other of the buckle and the vehicle. The plow shoe travels between the plates and absorbs energy by deforming at least one of the plates. An electronic adjuster mechanism adjusts the distance between the opposed plates to selectively increase or decrease the energy absorbing capacity of the load limiting device.

The document U.S. Pat. No. 5,273,240 describes an impact energy absorption system for aircraft seats. A seat is movable between a first unloaded position and a second crash induced position. A deforming die and an additional set of die jaws are connected to a seat mounting and defines an aperture of variable size. A deformable rod has a shoulder connecting the seat to the mounting the rod passing through the deforming die and the variable die jaws. During crash induced movement of the seat, the rod is pulled through the deforming die.

BRIEF SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide a new EAS that is adapted for absorbing energy of an object in a vehicle in a crash situation by decreasing acceleration and force acting on the object in the crash situation, wherein the EAS is automatically adjustable for use with arbitrary object masses.

This object is solved by an EAS that comprises the features of claim1. More specifically, according to the present invention an EAS that is adapted for absorbing energy of an object in a vehicle in a crash situation by decreasing acceleration and force acting on the object in the crash situation, comprises at least one plastically deformable energy absorber that is plastically deformable in the crash situation. A mass-dependent self-adjusting mechanism is provided. The mass-dependent self-adjusting mechanism is adapted for adjusting, on the basis of an underlying mass of the object, a required compensation force that is to be provided by the EAS in the crash situation for plastically deforming the at least one plastically deformable energy absorber in order to decrease the acceleration and force acting on the object.

According to one aspect of the present invention, the EAS decreases acceleration and force for an occupant or object in a vehicle in a crash situation. More specifically, in aviation crash events an occurring vertical acceleration must be reduced to prevent injuries of seat occupants in the aircraft. Therefore, corresponding seat pans are adapted for striking towards the aircraft floor in order to increase time and way for decreasing acceleration on bodies of corresponding seat occupants. The inventive EAS thereby absorbs the kinetic energy generated by the occupant's mass and provides for preferably constant and limited body loads, e. g. lumbar loads. Due to varying occupant anthropometrics, the EAS has to be adjusted to the occupant's weight for the best result.

Advantageously, such an adjustment is done by means of an automatic adjustment, i.e. the self-adjustment of the EAS to a suitable compensation force and, thus, an acceptable crash force in a crash situation. This self-adjustment is performed on the basis of a measurement of the object's weight, e. g. a measurement of a weight of an occupant of a seat in the vehicle, and is therefore referred to as a mass-dependent self-adjusting. In other words, the inventive EAS weights the mass of the occupant or object prior to the crash situation and automatically adjusts a compensation force required in the crash situation in order to provide constant deceleration of a seat pan of the crashworthy seat in the crash situation.

Preferably, the adjustment is autonomously done, i.e. without need for an intervention of an operator in the vehicle or an occupant of the vehicle. Training of the operator or the occupant for adjusting the EAS is, thus, not required. Consequently, a complex manual adjustment of the EAS due to a possible wide minimum to maximum occupant weight range on such a crashworthy seat can be avoided. The EAS preferably also includes a mechanism to limit underlying tripping characteristics independent of the measured occupant or object weight.

Advantageously, the inventive EAS allows provision of crashworthy seats for vehicles, i.e. seats having a single seating surface, which allow, e.g. when used in aircrafts, reduction of body load on occupants of the seats occurring in an aircraft crash. It furthermore allows for an automatic and advantageous load distribution of unbalanced loads to two or more EAS. Moreover, the inventive EAS is a simple and robust, light weight, low-maintenance, non-electrical mechanism without need for complex electronics and power supplies. It uses available technical solutions and logistical equipment known from aerospace environment in general and is retrofitable into existing solutions.

According to a preferred embodiment, the mass-dependent self-adjusting mechanism comprises at least one first and one second roller that are spaced apart from each other by means of at least one spring pushing the first and second rollers in opposed directions. The first and second rollers are adapted for applying the required compensation force to the at least one plastically deformable energy absorber in the crash situation for plastically deforming the at least one plastically deformable energy absorber in the crash situation.

According to a further preferred embodiment, the at least one plastically deformable energy absorber is a plastically deformable tube.

According to one aspect, the inventive EAS is integrated into or next to a seat in a vehicle and consists of at least two rollers that are adapted for deforming a tube during a crash situation of the vehicle. Thus, the kinetic energy of e.g. an occupant of the seat can be converted to deformation and thermal energy by the deformation of the tube. An underlying compensation force for the deformation is dependent from a required degree of deformation, which advantageously depends from a self-adjustable distance between the at least two rollers. More specifically, a lower distance between the at least two rollers results in a higher degree of deformation that requires a higher deformation force.

According to a further preferred embodiment, the first and second rollers are pre-loadable in direction of the at least one plastically deformable energy absorber in normal operation mode by the underlying mass of the object.

According to a further preferred embodiment, the mass-dependent self-adjusting mechanism comprises a support frame. The first and second rollers are moveably mounted to the support frame and are moveable towards each other inside the support frame in normal operation mode on the basis of the underlying mass of the object, against a pushing force provided by the at least one spring, in order to allow self-adjustment of a mass-dependent deformation distance between the first and second rollers in the support frame.

According to a further preferred embodiment, the mass-dependent deformation distance determines the required compensation force that is applied by the first and second rollers to the at least one plastically deformable energy absorber in the crash situation for plastically deforming the at least one plastically deformable energy absorber in the crash situation. The required compensation force increases if the mass-dependent deformation distance decreases.

According to a further preferred embodiment, the mass-dependent self-adjusting mechanism comprises at least one damper. The at least one damper is adapted for maintaining the self-adjusted mass-dependent deformation distance between the first and second rollers in the crash situation at least approximately.

According to a further preferred embodiment, the mass-dependent self-adjusting mechanism comprises inclined surface members. The first and second rollers are arranged on the inclined surface members such that pre-loading of the first and second rollers in direction of the at least one plastically deformable energy absorber in normal operation mode by the underlying mass of the object is translatable into a rolling movement of the first and second rollers along the inclined surface members in direction of the at least one plastically deformable energy absorber. The rolling movement is construed for resulting in a movement of the first and second rollers towards each other inside the support frame.

According to a further preferred embodiment, the mass-dependent self-adjusting mechanism comprises an inclined surface member support. The inclined surface members are releasably mounted to the inclined surface member support.

More specifically, an underlying spacing between the at least two rollers is adjusted by the objects or occupant's mass, i.e. its measured weight, the inclined surface members and the at least one spring. The inclined surface members are preferably fixed relative to the plastically deformable tube in normal operation mode and do not move relative to each other. The at least two rollers are preferentially guided horizontally in the inclined surface member support, such as a frame that is e.g. fixed to a seat pan. The damper-spring system defined by the at least one spring and the at least one damper is preferably only connected to the at least two rollers.

According to a further preferred embodiment, the mass-dependent self-adjusting mechanism comprises at least one trigger mechanism that is adapted for triggering release of the inclined surface members from the inclined surface member support in the crash situation.

According to one aspect of the present invention, the trigger mechanism blocks a horizontal or sideward movement of the inclined surface members in normal operation mode. The trigger mechanism preferably releases the inclined surface members, i.e. allows a horizontal or sideward movement thereof, only in a crash situation. Such a release is preferably independent from the object's weight and is only triggered if a predetermined acceleration is exceeded.

More specifically, preferably a trigger wheel fixes the inclined surface members from moving horizontally, i.e. sideward. An associated trigger mass is pushed upwards against a blocking member by a spring member. The trigger mass and the trigger wheel are connected by a lever. The lever is fixed on a pivot bearing. If the predetermined acceleration exceeds an adjusted value, the forces of the mass inertia exceed the spring forces and the lever starts rotating. The trigger wheel, thus, moves upward and releases the inclined surface members, which may consequently move horizontally, i.e. sideward.

According to a further preferred embodiment, the trigger mechanism comprises at least one trigger wheel for each one of the inclined surface members. The at least one trigger wheel is connected to a trigger mass and is maintained immobile against an associated inclined surface member in the normal operation mode by means of the trigger mass for maintaining the associated inclined surface member in a predetermined blocking position of the at least one trigger wheel on the inclined surface member support in the normal operation mode.

According to a further preferred embodiment, the trigger mechanism comprises at least one lever. The lever connects the at least one trigger wheel to the trigger mass. The lever is pivotally mounted to an associated pivot bearing and rotatable around the associated pivot bearing in response to an acceleration of the trigger mass in a predetermined acceleration direction occurring in a crash situation.

According to a further preferred embodiment, the lever is connected to a spring member. The spring member preloads the at least one trigger wheel by means of the lever into the predetermined blocking position.

According to a further preferred embodiment, the object in the vehicle is a vehicle seat or an occupant of the vehicle seat. The support frame is integrated into a seat pan of the vehicle seat.

Preferably, the entire EAS is part of the vehicle seat.

The present invention further provides a vehicle seat for a vehicle, in particular for a rotorcraft. The vehicle seat is provided with an energy absorbing system as described above.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1shows a vehicle seat1for a vehicle. According to one aspect of the present invention, the vehicle seat1is a crashworthy seat that is provided with an EAS2, and the vehicle is an aircraft, in particular a rotorcraft and, more particularly, a helicopter. However, it should be noted that the vehicle is not illustrated in detail, as the vehicle as such is not part of the present invention, so that illustration thereof can be omitted for simplicity of the drawings.

The crashworthy seat1illustratively comprises at least a seat pan1athat houses a support frame1b.Preferably, the support frame1bis integrated into the seat pan1a.The seat pan1aand the support frame1bare preferably adapted for accommodating at least partly the EAS2.

According to one aspect of the present invention, the EAS2is adapted for absorbing energy of the crashworthy seat1and/or an occupant of the crashworthy seat1in a crash situation of the vehicle by decreasing acceleration and force acting on the crashworthy seat1and/or the occupant of the crashworthy seat1in the crash situation. However, it should be noted that the crashworthy seat1and/or the occupant of the crashworthy seat1are merely cited and described as examples for any arbitrary object in the vehicle that may be equipped with the EAS2according to the present invention, such as e.g. cargo retainers and so on. Therefore, the terminology “object1” is used hereinafter instead of the terminology “crashworthy seat1”.

Preferably, the EAS2comprises a mass-dependent self-adjusting mechanism2aand at least one plastically deformable energy absorber8that is plastically deformable in a crash situation of the vehicle. The at least one plastically deformable energy absorber8is preferentially a plastically deformable tube.

According to one aspect of the present invention, the mass-dependent self-adjusting mechanism2ais at least adapted for adjusting, on the basis of an underlying mass of the object1, a required compensation force that is to be provided by the EAS2in a crash situation of the vehicle for plastically deforming the at least one plastically deformable tube8in order to decrease acceleration and force acting on the object1in the crash situation. For this, the self-adjusting mechanism2ais provided with at least one and, preferably, at least two rollers3that are adapted for applying the required compensation force to the at least one plastically deformable tube8in the crash situation of the vehicle for plastically deforming the at least one plastically deformable tube8in the crash situation.

Illustratively, the at least two rollers3comprise a first roller3aand a second roller3b.Therefore, by way of example and not for limiting the invention thereto, reference is only made to the first and second rollers3a,3bhereinafter.

The first and second rollers3a,3bare exemplarily arranged on two opposed peripheral sides of the at least one plastically deformable tube8with a displacement of illustratively 180°, by way of example on left and right sides thereof. However, other amounts of rollers and other arrangements thereof with respect to the at least one plastically deformable tube8are likewise possible. For instance, three rollers with a relative displacement of approximately 120° with respect to each other can likewise be applied, and so on.

Preferably, the first and second rollers3a,3bare moveably mounted to the support frame1b.More specifically, the first and second rollers3a,3bare preferably moveable towards each other inside the support frame1bin normal operation mode of the EAS2on the basis of the underlying mass of the object1, as described in more detail below. The support frame1bis, therefore, considered as being part of the mass-dependent self-adjusting mechanism2a.

According to one aspect of the present invention, the mass-dependent self-adjusting mechanism2afurther comprises inclined surface members4. The latter illustratively exhibit triangular cross sections and are arranged such that inclined surfaces thereof are facing each other and oriented towards the at least one plastically deformable tube8for respectively defining down-grades towards the at least one plastically deformable tube8.

By way of example, the inclined surface members4comprise at least a first inclined surface member4aand a second inclined surface member4b.Therefore, by way of example and not for limiting the invention thereto, reference is only made to the first and second inclined surface members4a,4bhereinafter. However, it should be noted that an underlying number of applied inclined surface members may vary dependent on an applied number of rollers and a desired configuration of the mass-dependent self-adjusting mechanism2a.

The first and second rollers3a,3bare preferably arranged on the first and second inclined surface members4a,4b,i.e. on the inclined surfaces that are facing each other. More specifically, the first roller3ais arranged on the first inclined surface member4aand the second roller3bis arranged on the second inclined surface member4b,such that pre-loading of the first and second rollers3a,3bin direction of the at least one plastically deformable tube8in normal operation mode of the EAS2by the underlying mass of the object1is translatable into a rolling movement of the first and second rollers3a,3balong the first and second inclined surface members4a,4bin direction of the at least one plastically deformable tube8. The rolling movement is preferentially construed for resulting in a movement of the first and second rollers3a,3btowards each other inside the support frame1b.

Preferably, the first and second inclined surface members4a,4bare releasably mounted to an inclined surface member support5. The latter is preferentially also part of the mass-dependent self-adjusting mechanism2a.

According to one aspect of the present invention, the mass-dependent self-adjusting mechanism2afurther comprises at least one trigger mechanism6that is adapted for triggering release of the first and second inclined surface members4a,4b,from the inclined surface member support5in a crash situation of the vehicle. Preferably, each one of the first and second inclined surface members4a,4bhas an associated trigger mechanism6.

The trigger mechanism6preferably comprises at least one trigger wheel6athat is connected to a trigger mass6c.The trigger wheel6ais maintained immobile against the associated one of the first and second inclined surface members4a,4bin the normal operation mode of the EAS2by means of the trigger mass6cfor maintaining its associated inclined surface member4a,4bin a predetermined blocking position of the at least one trigger wheel6aon the inclined surface member support5in the normal operation mode, as illustrated inFIG. 1.

More specifically, the trigger mechanism6preferably comprises at least one lever6f,which connects the trigger wheel6ato the trigger mass6c.The lever6fis pivotally mounted to an associated pivot bearing6eand rotatable around the associated pivot bearing6ein response to an acceleration of the trigger mass6cin a predetermined acceleration direction (12inFIG. 8) occurring in a crash situation of the vehicle.

Preferably, the lever6fis connected to a spring member6dthat preloads the trigger wheel6aby means of the lever6finto the predetermined blocking position. More specifically, the spring member6d,which is preferentially embodied as a rotary spring, preferably preloads the lever6fsuch that the trigger mass6cis pushed upwards—inFIG. 1—against an associated blocking member6b.Illustratively, the latter is implemented as a part of the inclined surface member support5. Consequently, as the lever6fpivots, respectively rotates, around the associated pivot bearing6e,the trigger wheel6ais pushed downwards—inFIG. 1—, such that the trigger wheel6aabuts against its associated inclined surface member4a,respectively4b.The latter is, thus, blocked and maintained in the predetermined blocking position, wherein an outwardly directed horizontal, i.e. sideward, movement of its associated inclined surface member4a,respectively4b,is prevented.

According to one aspect of the present invention, the mass-dependent self-adjusting mechanism2afurther comprises at least one spring7athat pushes the first and second rollers3a,3bin opposed directions. Thus, the first and one second rollers3a,3bare spaced apart from each other by means of a pushing force that is provided by the at least one spring7a,and an adjustable deformation distance (10ainFIGS. 3 and 10binFIG. 6) between the first and second rollers3a,3bin the support frame1bis created.

The mass-dependent self-adjusting mechanism2apreferably further comprises at least one damper7b.The at least one damper7bis preferentially adapted for maintaining the adjustable deformation distance (10ainFIGS. 3 and 10binFIG. 6) between the first and second rollers3a,3bat a respectively adjusted value in a crash situation of the vehicle at least approximately. Preferably, the at least one damper7bis a viscous damper that hydro-mechanically “memorizes” a respectively adjusted deformation distance (10ainFIGS. 3 and 10binFIG. 6). The at least one damper7band the at least one spring7apreferably define a spring-damper unit7.

It should be noted that the adjustable deformation distance (10ainFIGS. 3 and 10binFIG. 6) determines the required compensation force that is applied by the first and second rollers3a,3bto the at least one plastically deformable tube8in a crash situation of the vehicle for plastically deforming the at least one plastically deformable tube8in the crash situation. Preferably, the required compensation force increases if the adjustable deformation distance (10ainFIGS. 3 and 10binFIG. 6) decreases and it decreases if the adjustable deformation distance (10ainFIGS. 3 and 10binFIG. 6) increases.

In normal operation mode of the EAS2, the first and second rollers3a,3bare pre-loadable in direction of the at least one plastically deformable tube8by the underlying mass of the object1. More specifically, the first and second rollers3a,3bare moveable towards each other inside the support frame1bin the normal operation mode on the basis of the underlying mass of the object1against a pushing force provided by the at least one spring7aof the spring-damper unit7, in order to allow self-adjustment of the adjustable deformation distance (10ainFIGS. 3 and 10binFIG. 6). Therefore, the adjustable deformation distance (10ainFIGS. 3 and 10binFIG. 6) is also referred to as the “mass-dependent deformation distance” hereinafter. This self-adjustment of the mass-dependent deformation distance (10ainFIGS. 3 and 10binFIG. 6) is preferably always executed in an initial adjustment phase that is performed each time the mass-dependent self-adjusting mechanism2ais used in normal operation mode of the EAS2, as described below.

In the initial adjustment phase in the normal operation mode of the EAS2, the first and second rollers3a,3bare pushed in the direction of the at least one plastically deformable tube8by the underlying mass of the object1, which applies a load9to the first and second rollers3a,3b.The first and second rollers3a,3bare, thus, forced to perform a rolling movement along the first and second inclined surface members4a,4bin the direction of the at least one plastically deformable tube8, i.e. inFIG. 1downwards the first and second inclined surface members4a,4b.This rolling movement is performed against the pushing force of the at least one spring7aof the spring-damper unit7and, thus, translated by the inclined surface members4a,4binto generation of a compression force for compression of the at least one spring7a,whereby the mass-dependent deformation distance (10ainFIGS. 3 and 10binFIG. 6) is adjusted dependent on the weight of the underlying mass of the object1. The rolling movement stops at a point, where an equilibrium between the pushing force of the at least one spring7aand the generated compression force is reached, so that the mass-dependent deformation distance (10ainFIGS. 3 and 10binFIG. 6) is adjusted for the underlying mass of the object1. This adjusted mass-dependent deformation distance (10ainFIGS. 3 and 10binFIG. 6) is then preferably maintained at least essentially invariable by means of the at least one damper7bof the spring-damper unit7as long as the load9is applied to the first and second rollers3a,3b.

It should, however, be noted that the form of the first and second inclined surface members4a,4band underlying spring characteristics of the at least one spring7aaffect the adjusted mass-dependent deformation distance (10ainFIGS. 3 and 10binFIG. 6). Generally, a comparatively small mass-dependent deformation distance (10ainFIGS. 3 and 10binFIG. 6) results in a comparatively high degree of plastic deformation of the plastically deformable tube8in a crash situation and a comparatively high compensation force for deformation, while a comparatively great mass-dependent deformation distance (10ainFIGS. 3 and 10binFIG. 6) results in a comparatively low degree of plastic deformation of the plastically deformable tube8in a crash situation and a comparatively low compensation force for deformation.

FIG. 2shows the EAS2ofFIG. 1with the mass-dependent self-adjusting mechanism2aafter the initial adjustment phase in the normal operation mode of the EAS2as described above with reference toFIG. 1. Preferably, the mass-dependent self-adjusting mechanism2ais provided with two separate spring-damper units7, each comprising at least one spring7aand at least one damper7b,which are preferentially arranged laterally with respect to the first and second rollers3a,3b,preferably in the support frame1bofFIG. 1.

According to one aspect of the present invention, the lever6fof the trigger mechanism6is embodied as a frame that interconnects the trigger wheel6aand the trigger mass6c.However, it should be noted that this implementation is merely shown by way of example and not for limiting the invention accordingly. Instead, the lever6fmay also be embodied as a lever arm, so that e.g. two trigger mechanisms6with arm-like levers6fcan be employed per inclined surface member, i.e. the first or second inclined surface member4aor4b,and so on.

FIG. 3shows the plastically deformable tube8ofFIG. 1andFIG. 2after a plastic deformation thereof by means of the first and second rollers3a,3bin a crash situation. As can be seen fromFIG. 3, the tube8now no more exhibits a circular cross section like inFIG. 1andFIG. 2, but instead an oval cross section, as it was compressed by the first and second rollers to a mass-dependent deformation distance10athat was initially adjusted as described above.

FIG. 4shows the object1ofFIG. 1with the EAS2ofFIG. 1that comprises the mass-dependent self-adjusting mechanism2aofFIG. 1in an initial adjustment phase in the normal operation mode of the EAS2in a case, wherein the applied load9is greater than inFIG. 1. This happens if the underlying mass of the object1is greater than inFIG. 1. In this case, the first and second rollers3a,3bare pushed further towards the plastically deformable tube8than inFIG. 1, as the applied load9is suitable for generating a greater compression force for compression of the at least one spring7aof the spring-damper unit7.

FIG. 5shows the EAS2ofFIG. 4with the mass-dependent self-adjusting mechanism2aafter the initial adjustment phase in the normal operation mode of the EAS2. The initial adjustment phase is performed similar to what is described above with reference toFIG. 1, so that a more detailed description thereof can be omitted for brevity and conciseness.

FIG. 6shows the plastically deformable tube8ofFIG. 4andFIG. 5after a plastic deformation thereof by means of the first and second rollers3a,3bin a crash situation. As can be seen fromFIG. 6, the tube8now no more exhibits a circular cross section like inFIG. 1andFIG. 2, but instead an oval cross section, as it was compressed by the first and second rollers to a mass-dependent deformation distance10bthat was initially adjusted as described above.

It should be noted that the mass-dependent deformation distance10bis smaller than the mass-dependent deformation distance10aofFIG. 3. This is necessary as the required compensation force that must be applied by the first and second rollers3a,3bto the plastically deformable tube8for plastically deforming the latter in a crash situation must be greater for comparatively great underlying masses of the object1, than for comparatively small underlying masses of the object1, in order to achieve a suitable energy absorption/attenuation.

FIG. 7toFIG. 9show the EAS2ofFIG. 4that comprises the mass-dependent self-adjusting mechanism2aofFIG. 4in an exemplary crash situation. In other words, the crash situation is described by way of example on the basis of the EAS2as described above with reference toFIG. 4, wherein the applied load9of the object1ofFIG. 4is comparatively great and the mass-dependent deformation distance consequently comparatively small, i.e. exemplarily corresponds to the mass-dependent deformation distance10bofFIG. 6.

FIG. 7shows the EAS2after the initial adjustment phase in normal operation mode of the EAS2according toFIG. 4upon occurrence of a crash situation. Illustratively, occurrence of the crash situation consists of results in an acceleration of the object1ofFIG. 4, i.e. the seat pan1aofFIG. 4, in a crash situation movement direction11. At the beginning of this acceleration, the trigger mechanism6blocks, i.e. maintains, the inclined surface member4a,respectively4b,in the predetermined blocking position, wherein an outwardly directed horizontal, i.e. sideward, movement of the inclined surface member4a,respectively4b,is prevented.

FIG. 8shows the EAS2ofFIG. 7upon activation of the trigger mechanism6by means of the acceleration in the crash situation movement direction11according toFIG. 7. If this acceleration exceeds a predetermined value, the forces of the mass inertia of the trigger mass6cof the trigger mechanism6exceed the spring forces of the spring member6dof the trigger mechanism6and its lever6fstarts rotating, i.e. pivoting, such that the trigger mass6cmoves into a trigger mass acceleration direction12—i.e. downwards inFIG. 8—and that the trigger wheel6aof the trigger mechanism6moves into a trigger wheel release movement direction15—i.e. upwards inFIG. 8—and, thereby, releases the inclined surface member4a,respectively4b,from its blocking position. The first and second inclined surface members4a,4bmay, thus, move horizontally, i.e. sideward, on the inclined surface member support5.

FIG. 9shows the EAS2ofFIG. 8after an exemplary horizontal, i.e. sideward movement of the inclined surface members4a,4bon the inclined surface member support5in an inclined surface member sideward movement direction13. It should be noted that this sideward movement is forced by the first and second rollers3a,3b,which are accelerated in the crash situation in an associated deformation movement direction14towards the plastically deformable tube8and, thus, push the inclined surface members4a,4boutwardly while rolling on them.

It should be noted that during this rolling, the mass-dependent deformation distance10bofFIG. 6is maintained by means of the damper7bof the spring-damper unit7. In fact, the at least one damper7bis preferably adapted for not responding in the very short and quickly running crash situation.

Consequently, the first and second rollers3a,3bperform a rolling movement along at least a part of the plastically deformable tube8, while the mass-dependent deformation distance10bofFIG. 6is maintained. This leads to a plastic deformation of the plastically deformable tube8as illustrated inFIG. 6.

It should be noted that modifications to the above described embodiments are within the common knowledge of the person skilled in the art and, thus, also considered as being part of the present invention. For instance, the inventive EAS cannot only be applied to crashworthy seats, but also e. g. in storage compartments of vehicles that are provided with cargo retainers, and so on. Furthermore, the plastically deformable tube8described above can be filled with a material that absorbs most of the energy in a crash situation. This will lead to a more linear stopping force over deformation degree characteristics. It also decreases the risk of buckling of the tube.

REFERENCE LIST

4inclined surface members

4afirst inclined surface member

4bsecond inclined surface member

5inclined surface member support

10alow weight deformation measure

10bhigh weight deformation measure

11seat pan crash situation movement direction

12trigger mass acceleration direction

13inclined surface member sideward movement direction

14frame mounted roller deformation movement direction

15trigger wheel release movement direction