WO2004081407A2

WO2004081407A2 - Device for damped transmission of a load acting thereon, and vehicle seat installation equipped therewith

Info

Publication number: WO2004081407A2
Application number: PCT/NL2004/000143
Authority: WO
Inventors: Johannes Theodorus Marie Rasenberg
Original assignee: Rasenberg Johannes Theodorus M
Priority date: 2003-02-25
Filing date: 2004-02-25
Publication date: 2004-09-23
Also published as: WO2004081407A3; NL1022773C2; EP1599358A2; NL1022773A1

Abstract

The invention relates to a device for damped transmission of a load acting thereon, with a member for taking up the load, a member for relinquishing the damped load, and a number of elements (13) arranged therebetween which are deformable under the influence of the load. The deformable elements (13) are herein formed such that the resistance of the device remains at least the same, or even increases, as the deformation thereof increases. Each deformable element (13) transmits the load until its failure load is reached, whereafter the load is transmitted by a subsequent deformable element (13). The invention also relates to an installation for mounting a seat in a vehicle, which is provided with one or more damped load-transmitting devices of this type arranged between the construction of the vehicle and the seat. Such an installation damps a significant part of the loads in the case of a collision.

Description

DEVICE FOR DAMPED TRANSMISSION OF A LOAD ACTING THEREON, AND VEHICLE SEAT INSTALLATION EQUIPPED THEREWITH

The invention relates to a device for damped transmission of a load acting thereon. Such damped load- transmitting devices are already known in a large number of variants. The damped transmission of loads is of great importance in many technical fields, particularly where the object is to save people from discomfort or even injury or to protect vulnerable machines and objects from damage. An important application is vehicle engineering, where damping systems are used on a large scale in order to limit as far as possible damage and injury resulting from collisions.

The invention has for its object to propose a device for damped transmission of loads, which has a compact and simple construction, can be manufactured at low cost and is able to protect people from the consequences of relatively strong impact loads, such as for instance occur during an accident. The invention provides for this purpose a damped load-transmitting device, comprising at least one member for taking up the load, at least one member for relinquishing the damped load, and at least one element arranged therebetween and deformable under the influence of the load, wherein the or each deformable element is formed such that the resistance of the device remains at least the same as the deformation thereof increases. By making use of deformable damping elements, i.e. mechanical damping wherein the resistance to deformation does not decrease, relatively high loads can be damped at a relatively small deformation, thus also a relatively small displacement compared to for instance a hydraulic damper. Such a mechanical damping device furthermore has a simpler construction and requires less maintenance than a hydraulic damper. Finally, such a mechanical damper responds more quickly than a hydraulic damper, which is a great advantage in accidents .

The or each deformable element is preferably even formed such that, as the deformation increases, the resistance of the device not only remains the same, but even increases. Such a progressive action results in a very effective reduction of forces in the case of relatively small deformations or displacements .

A preferred embodiment of the device according to the invention is provided with a number of deformable elements which, as the deformation increases, successively transmit at least part of the load from the take-up member to the relinquishing member. An excellent damping is thus achieved over a wide range of loads. A very well controllable damping is then obtained when only one of the deformable elements at a time transmits the load from the take-up member to the relinquishing member. This can be achieved in that each deformable element transmits the load until its failure load is . reached, whereafter the load is transmitted by a subsequent deformable element.

In order to be able to successively connect the deformable elements for the purpose of transmitting the load, they are fixed in each case with one end to the relinquishing member, while the other end is in engagement with the take-up member or is brought into engagement therewith as deformation increases.

This can be achieved when the deformable elements have different lengths. In order to ensure here that the deformation of each element remains roughly the same as the load increases, the deformable elements preferably have differing rigidity.

On the other hand, it is also possible to envisage that the deformable elements are each fixed to the relinquishing member via a substantially non-deformable assembly part, and that these assembly parts have different lengths. The deformable elements can thus even have equal lengths and therefore equal deformations. A readily predictable deformation and a simple integration of the device into a construction is achieved when the deformable elements are pull elements or push elements and thus perform a substantially linear movement. The deformable elements can herein be arranged parallel to each other between the take-up member and the relinquishing member. Particularly in the case of push elements it is also readily possible to envisage these being arranged concentrically.

In order to prevent an excessive movement of the device under the influence of a load, it is preferably provided with at least one stop member for bounding the relative displacement of the take-up member and the relinquishing member. When the deformable elements have deformed so far that the stop member is reached, the load is transmitted further undamped. When the device according to the invention is provided with at least two take-up members placed on either side of the relinquishing member and connected thereto by associated deformable elements, it can be used to damp loads in two opposite directions. The invention further relates to an installation for mounting a seat in a vehicle. Seats have heretofore been mounted rigidly in vehicles, optionally via a rail system to allow adjustment of the position of the seat in longitudinal direction. Such a rigid mounting has the drawback that loads on the construction of the vehicle, for instance as a result of collisions, are transmitted directly to the seat and from there to the body of a passenger. These loads can quickly cause serious injury.

The invention therefore has for its object to propose an improved installation of a seat in a vehicle. According to the invention an installation for mounting a seat in a vehicle comprises for this purpose at least one damped load-transmitting device of the above described type arranged between a part of the construction of the vehicle and the seat. By interposing such a device, loads which occur during a collision are transmitted to the passenger in damped manner, thereby minimizing the chance of serious injury.

The mounting installation according to the invention is preferably provided with at least two load- transmitting devices acting in opposite directions, so that the passenger is protected in both rear-end collisions and head-on collisions. Instead of two devices acting in oppqsing directions- a single double- action device can of course also be applied for this purpose.

The invention will now be elucidated on the basis of a number of embodiments, with reference to the annexed drawing in which corresponding components are designated with reference numerals increased by 100, and in which:

Fig. 1 is a side view of an installation for mounting a seat in a vehicle, wherein use is made of two oppositely acting devices according to the invention, Fig. 2 shows a schematic longitudinal section of one of the devices of fig. 1, wherein the deformable elements are pull elements,

Fig. 3 shows a view corresponding with fig. 2 of an alternative embodiment of this device, and Fig. 4 is a view corresponding with fig. 2 and 3 of an embodiment of the device wherein the deformable elements are push elements .

An installation 1 for mounting a seat 2 in a vehicle 3 (fig. 1) comprises two rails 4 (only one of which is shown here) , over each of which two carriages 5 are slidable. Each rail 4 is fixed to a part of the construction of vehicle 3, here the base plate 6, and each carriage 5 is fixed to frame 7 of seat 2. Rails 4 and carriages 5 have means co-acting in known manner for fixing carriages 5 in determined positions, for instance in the form of spring-loaded pins 8 which can be placed into openings 9 of rails 4. A passenger can hereby set a desired position of seat 2. In order to protect the passenger against high loads in the case of a collision, which loads could result in injury, each carriage 5 is fixed according to the present invention to frame 7 of seat 2 via a device 10 for damped transmission of a load acting thereon. In the shown embodiment there are thus four such damped load-transmitting devices 10, two on the left-hand side and two on the right-hand side. The two devices 10F and 10R herein act in opposite directions on each side. The foremost device 10F serves to damp a rearward-directed load F_F which is transmitted from the front side of vehicle 3 via base plate 6 to seat 2 in the case of a head-on collision. Conversely, the rearmost device 10R damps a forward-directed load F_R which is transmitted to the seat from the rear through base plate 6 when vehicle 3 is struck from the rear.

Each damped load-transmitting device 10 comprises a member 11 connected to carriage 5 for taking up the load, a member 12 connected to seat frame 7 for relinquishing the damped load, and a number of elements 13 arranged therebetween and deformable under the influence of the load. In this embodiment are shown eleven deformable elements 13_x, 13₂, ... , 13_n in the form of mutually parallel pull rods of different lengths, but more or fewer elements could of course also be used depending on the expected loads and the available space. The deformable elements 13,-13]^ are embodied and dimensioned such that the resistance of device 10 increases as deformation thereof increases. In this manner an almost completely uniform displacement of seat 2 with the passenger thereon can be achieved.

The deformable elements or pull rods 13_!-13_u are each fixed at one end 14₁-14₁₁ to relinquishing member 12, while the other end 15_x of the shortest pull rod 13_x is in engagement with take-up member 11, while the other ends 15₂-15_n of the other pull rods 13₂~13_u are brought into engagement with the take-up member when the load increases. Take-up member 11 here takes the form of a beam 16 with a number of parallel openings ll_l-'ll_llr through which pull rods 13_α-13_u protrude. Each pull rod 13₃-13^ is provided on its relevant outer end lSj-lδn with a widened head which engages on beam 16.

In the shown embodiment the pull rods 13 are dimensioned such that only one of them at a time transmits the load from take-up member 11 to relinquishing member 12, until its failure load is reached, whereafter the load is transmitted by a subsequent pull rod 13. Starting with the first pull rod 13_x, each pull rod is thus loaded until it collapses, wherein precisely at the moment of collapse of a pull rod 13_n the head 15_n+1 of the following pull rod 13_n+1 is in engagement with beam 16, so that the load is therefore taken up by this pull rod 13_n+1. For this purpose the length in unloaded state of this following pull rod 13_n+1 must be chosen to equal the unloaded length of the preceding pull rod 13_n increased by the elongation of this pull rod 13_n at the collapse thereof.

The tensile strength of each subsequent pull rod 13_n+1 is herein of course greater than that of the preceding pull rod 13_n. This can be achieved by increasing the cross-sectional area and/or choosing a stronger material. Instead of a single subsequent pull rod 13_n+1 with increased cross-sectional area, two subsequent pull rods 13_n+1(l) and (2) of equal length could for instance be used, which could each have the same cross-sectional area as the preceding pull rod 13_n.

When all pull rods 13 are manufactured from the same material, the elongation at break thereof will be the same, so that the elongation increases progressively as the length of rods 13 increases. This is therefore also the case for the displacement of relinquishing member 12 (and therefore seat 2) relative to take-up member 11 (and thus vehicle 3) . In order to prevent this, the longer pull rods 13 would have to be manufactured from a material with a lower elongation at break than the shorter members.

Each device 10 is otherwise also provided with a stop member 18 for bounding the relative displacement of take-up member 11 and relinquishing member 12. Relinquishing member 12 comes to rest against this stop member 18 as soon as the final pull rod 13₁₂ has also collapsed. From that moment the load is of course further transmitted in undamped manner.

Table I below gives an example of the loads on the successive pull rods

and the displacement of relinquishing member 12 relative to take-up member 11 occurring therein. Use is made of round pull rods 13.

00

Table II shows at which speed difference the stated loads occur, wherein a duration of the collision of 0.078 sec. is taken as a starting point. Two cases are calculated here, i.e. a combination of seat 2 and passenger with a total mass of 100 kg, and a combination with a total mass of 150 kg. As stated, the loads are transmitted in each case from vehicle 3 to seat 2 by two devices 10.

Table II

* per damped load-transmitting device 10

In an alternative embodiment of device 10 according to the invention, the deformable elements or pull rods 13 each have an equal length but they are fixed to relinquishing member 12 via substantially non-deformable assembly parts 19 (fig. 3) . The successive assembly parts 19_x, 19₂, - 19₇ herein have increasing lengths. In this embodiment the pull rods further have a tensile strength which only increases slightly. Each subsequent pull rod 13_n can for instance have a diameter which is only 2% greater than that of the preceding pull rod 13_n. _!, so that its surface area is then about four percent larger. When the materials are the same, this ratio then of course also applies for the tensile strength. Owing to this configuration the elongation of each pull rod 13 is roughly equal at collapse, so that a uniform deformation occurs.

In yet another embodiment of the damped load- transmitting device 110 (fig. 4), the deformable elements 113, five of which are shown here, are adapted to absorb a pressure load instead of a tensile load. These push elements HSj-llS_s are herein arranged concentrically, wherein the longest and thinnest element 113-_L is embodied as a centrally placed rod, while the other push elements 113₂-113₅ take the form of tubes of increasing diameter and decreasing length placed therearound. The operating principle of this embodiment of device 110 is largely the same as that of the first embodiment, in the sense that the load is first borne by the relatively long and thin element 113]_,, until this buckles, whereafter the load will be borne by the longest and thinnest tube 113₂, until this also buckles, and so on. One difference however is that the elements 113 which have already collapsed in this embodiment continue to carry the load to some extent, since they remain in engagement with both take-up member 11 and relinquishing member 12. The failure behaviour of device 110 and the build-up of the loads therein is hereby slightly more difficult to predict as a whole and a resort has to be made to simulations for this purpose. This embodiment of device 110 can on the other hand take a more compact form, among other reasons because a separate stop member can be omitted.

The device according to the invention thus makes it possible to transmit relatively high loads, such as for instance occur in a vehicle during a collision, in well- damped manner. In the case of a rear-end collision so- called "whiplash" injury can be avoided by applying this device. The loads occurring in a head-on collision can be so greatly reduced by this device that the effectiveness of the other provisions for protecting the passengers of the vehicle, such as seatbelt tensioners and air bags, is improved. It will probably even be possible to suffice with smaller air bags.

Because the damping takes place by mechanical deformation, a relatively large amount of energy can be dissipated in a compact construction. The device is furthermore maintenance-free. The device is also very suitable for later incorporation into existing constructions . Although the invention is elucidated above on the basis of two embodiments, it will be apparent that the invention is not limited thereto. Instead of pull rods, tension cables could thus be used which could therefore already be fixed with one outer end to the take-up member in the unloaded state, and could hang slack until loaded.

Instead of concentric, tubular push elements, adjacently placed push rods could also be applied. The separate, concentric push members could also be replaced with a single integrated push member with a resistance increasing in the direction of deformation. Such a push member could for instance take a conical or stepped form.

Other types of deformable element, for instance torsion elements, could also be used if they could be integrated into the construction in logical manner. It is not otherwise necessary for a subsequent deformable element to be loaded only when the preceding element has collapsed. Also during the phase of elastic deformation of the one element a subsequent element could already be loaded. A more even transition is hereby obtained.

Any material is in principle suitable for the deformable elements, wherein for practical reasons metals and fibre-reinforced plastics are particularly envisaged.

Instead of the shown installation with two oppositely acting devices in each case, it is further also possible to opt for the use of a double-action device with a central relinquishing member and take-up members and deformable elements on either side thereof. The deformable elements which serve to transmit the loads in the case of a head-on collision can herein be made longer than the elements for the rear-end collision, since there will be more free space on the front side of the seat. The generally higher loads in the case of head-on collisions can hereby be damped very well. This is of course also the case when use is made of two oppositely acting devices.

Finally, the application of the device according to the invention is not limited to vehicle seats. Other components intended to absorb energy by means of deformation or displacement in the case of collisions, such as vehicle bumpers, could also be mounted via such a device. This also applies for protection systems in the doors of a vehicle. This damping principle could even be applied in the deformable parts themselves, for instance in a so-called crushable zone.

The scope of the invention is therefore defined solely by the appended claims.

Claims

1. Device for damped transmission of a load acting thereon, comprising at least one member for taking up the load, at least one member for relinquishing the damped load, and at least one element arranged therebetween and deformable under the influence of the load, wherein the or each deformable element is formed such that the resistance of the device remains at least the same as the deformation thereof increases.

2. Damped load-transmitting device as claimed in claim 1, characterized in that the or each deformable element is formed such that the resistance of the device increases as the deformation thereof increases.

3. Damped load-transmitting device as claimed in claim 1 or 2, characterised by a number of deformable elements which, as the deformation increases, successively transmit at least part of the load from the take-up member to the relinquishing member.

4. Damped load-transmitting device as claimed in claim 3, characterised, isi that only one of the deformable elements at a time transmits the load from the take-up member to the relinquishing member.

5. Damped load-transmitting device as claimed in claim 3 or 4, characterized in that each deformable element transmits the load until its failure load is reached, whereafter the load is transmitted by a subsequent deformable element.

6. Damped load-transmitting device as claimed in any of the claims 3-5, characterized in that the deformable elements are fixed in each case with one end to the relinquishing member, while the other end is in engagement with the take-up member or is brought into engagement therewith as deformation increases.

7. Damped load-transmitting device as claimed in claim 6, characterized in that the deformable elements have different lengths.

8. Damped load-transmitting device as claimed in claim 7, characterized in that the deformable elements have differing rigidity.

9. Damped load-transmitting device as claimed in claim 6, characterized in that the deformable elements are each fixed to the relinquishing member via a substantially non-deformable assembly part, and the assembly parts have different lengths.

10. Damped load-transmitting device as claimed in any of the claims 3-9, characterized in that the deformable elements are pull elements.

11. Damped load-transmitting device as claimed in any of the claims 3-9, characterised in that the deformable elements are push elements.

12. Damped load-transmitting device as claimed in any of the claims 3-11, characterized in that the deformable elements are arranged parallel to each other between the take-up member and the relinquishing member.

13. Damped load-transmitting device as claimed in any of the claims 3-12, characterized in that the deformable elements are arranged concentrically between the take-up member and the relinquishing member.

1 . Damped load-transmitting device as claimed in any of the foregoing claims, characterized by at least one stop member for bounding the relative displacement of the take-up member and the relinquishing member.

15. Damped load-transmitting device as claimed in any of the foregoing claims, characterized by at least two take-up members placed on either side of the relinquishing member and connected thereto by associated deformable elements.

16. Installation for mounting a seat in a vehicle, comprising at least one damped load-transmitting device as claimed in any of the foregoing claims arranged between a part of the construction of the vehicle and the seat .

17. Mounting installation as claimed in claim 16, characterized by at least two load-transmitting devices acting in opposite directions .