NL1019869C2 - Pyrotechnic control device and seat equipped with it, as well as damping element to be used therein. - Google Patents

Description

PYROTECHNICAL CONTROL DEVICE AND CHAIR EQUIPPED WITH THAT, AND DAMPER TO BE APPLIED THEREOF

The invention relates to an operating device for moving an object connected thereto.

In many situations it is of great importance that an object can be moved over some distance by means of an operating device in a very short time.

In this context, in particular, safety systems can be envisaged, for example in vehicles, which in the event of an incident, in particular a collision, must protect the occupants of the vehicle against injury. However, these safety systems must not affect the normal operation of systems that are furthermore present and must therefore be present in the background.

An example of a situation where there is a need for such a fast-acting safety system in the background is a sudden forward acceleration of a vehicle seat, for example as a result of a rear-end collision, where the passenger is forcefully pressed against the backrest. Known vehicle seats can be adjusted in a variety of ways, which is at the expense of the structural strength and stiffness. As a result, these seats generally offer insufficient support and protection in the event of such a rear-end collision. With the known vehicle seats 25, the backrest therefore moves very quickly against the load direction under the load, which starts when the pelvis of the passenger touches the backrest. As a result, the back of the occupant is released from the backrest, and only hits it again at the end of the movement with extra force. The headrest, which is after all mounted on top of the backrest, also carries out this rapid movement, so that the head of the occupant will also strike the headrest with force at the end of the movement. The force of the blow with which the back and head hit the backrest and headrest often leads to injuries known under the collective name "whiplash".

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In a patent application not previously published, the applicant has already proposed that in the case of a rear-end collision the backrest of a chair should be pivoted about an axis which is placed approximately halfway down the backrest. This pivoting movement should be initiated by the contact of the pelvis with the underside of the handrail, whereby the upper side thereof would pivot in the opposite direction, that is to say forward, and would catch the upper body and head of the occupant. In practice, however, this pivoting movement appears to be reversed almost immediately after its creation, at the moment that a part of the back above the pivot axis comes into contact with the backrest.

The invention now has for its object to provide an operating device with which, for example, a rapid movement of a backrest of a vehicle seat can be generated, in order to prevent back, neck and head injuries in the event of a rear-end collision. According to the invention this is achieved by an operating device which is provided with a cylinder connected to a pyrotechnic element and a piston movably accommodated therein under the influence of the pyrotechnic element. By making use of a pyrotechnic element, the piston, which can be connected to an object to be moved, can be moved through the cylinder very quickly.

The operating device is preferably provided with means for blocking the piston in the cylinder in a rest position. Hereby unintended movements of the object connected to the piston can be avoided.

In a constructionally simple embodiment, these blocking means are formed by at least one collapsing member arranged between the piston and the cylinder. This collapsing member, which may, for example, have the shape of a protruding edge of the piston resting against a shoulder in the cylinder, will simply collapse in the event of a load on the piston by activating the pyrotechnic element, after which the piston can freely to move.

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According to a preferred embodiment, the operating device is also provided with means for fixing the piston in the cylinder at an end of its stroke movement. As a result, the actuating device further behaves as a rigid whole after it has been activated, as a result of which the further movements of the object connected therewith are predictable and controllable. Moreover, the fixed end position of the piston forms a clear indication that the operating device has been used.

These fixation means can for instance be formed by a tapered end part of the cylinder, and a conical end part of the piston that fits tightly therein. Due to the force and speed with which the piston is moved after activation of the pyrotechnic element, it will lock into the tapered end part of the cylinder with a suitable choice of the materials of cylinder and piston.

According to another aspect the invention also provides means for damping a return movement of an element, such as for instance a piston of an operating device as described above. A constructionally simple embodiment is thereby obtained if the damping means are plastically deformable.

For damping a pressure load, the cylinder and / or the piston can then be of divided design, and the damping means comprise at least one compressible damping member arranged between the parts. This way a compact construction is achieved. In order to achieve a very uniform and easily adjustable damping, the damping member is preferably tubular and has at least one protruding stabilizing edge. A relatively light construction that can nevertheless withstand high loads is obtained when the tubular part of the damping member and / or the stabilizing edge is made of metal, for example aluminum.

On the other hand, it is also conceivable that the damping member comprises at least one chamber filled with a compressible mass. The damping means can thus be formed simply and at low costs.

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Moreover, when the load to be damped is a tensile rather than a compressive load, the piston preferably has a plastic extensible piston rod.

The invention also relates to a chair 5 in which an operating device and / or damping means as described above can / can be applied. A vehicle seat previously developed by the applicant comprises a frame mounted in the vehicle, a seat mounted thereon and a backrest connected thereto, at least a part of which is movable substantially parallel to the seat. The invention now provides a chair of this type, which is further provided with at least one operating device for causing at least the movable part of the backrest to move with the load in response to a shock load. Thus, in the event of a rear-end collision, the backrest can very quickly move forward to catch the upper body and head of the occupant.

An effective collection movement is achieved when the seat and / or backrest can be tilted about a horizontal axis directed substantially transversely to the direction of movement of the vehicle. Thus, the entire chair can tilt forward to reduce the distance to the user's body. The tilt-axis line can herein be determined by at least one hinge placed near an edge of the seat remote from the backrest.

An even better guided movement is obtained when the seat and / or backrest is connected to the frame by at least two pivot arms arranged in the direction of movement of the vehicle with spacing. The movement can be accurately controlled by adjusting the mutual position and length of the swivel arms.

The at least one operating device is then advantageously arranged between the seat and / or backrest and the frame. Incidentally, it may be advantageous in some cases to make use of separate means arranged between the seat and / or backrest and the frame for damping a return movement of the seat and / or backrest, so that the operating function, the movement of (parts of) the chair is separated from that of damping the return movement. Finally, the invention relates to a damping member for use in the operating device as described above.

The invention will now be explained with reference to a number of examples, with reference to the accompanying drawing, in which: 1A to C show a first embodiment of the operating device according to the invention during different phases of its use,

FIG. 2A to C are views corresponding to fig. 1 of a second embodiment of the operating device,

FIG. 3A to C show views corresponding to the previous figures of a third embodiment of the operating device,

FIG. 4A to C are corresponding views of a fourth embodiment of the operating device according to the invention,

FIG. 5A and B show schematic side views of a vehicle seat in which an operating device according to the invention is applied, respectively during a rest position and when the operating device is used,

FIG. 6A and B are views corresponding to fig. 5 of an alternative embodiment of the operating device when used in a vehicle seat,

FIG. 7A and B are views corresponding to the previous figures 30 of a third arrangement of the operating device when used in a vehicle seat, and FIG. 8A and B show a vehicle seat which is provided with means for damping its movement.

An operating device 1 (Fig. 1) comprises a cylinder 2 and a piston 3, which is movable therein. The cylinder 2 is provided with a protruding part 4 in which pyrotechnic element 5 is included, which upon activation causes a gas discharge in the cylinder 2. The piston 3 is connected to a piston rod 6, which at one end through an opening 8 in a protruding from the end wall 9 of the cylinder 2.

In the example shown, the cylinder 2 is in fact designed in two parts, and has a continued part 10 which is received in an end wall 11, and which has a bore 12 into which the piston rod 6 protrudes. The continued part 10 is provided with damping means 14, here in the form of a relatively thin-walled tube 15 and a number of stabilizing rings 16 arranged in between. In the example shown, the tube 15 and the stabilizing rings 16 are formed as a whole with one another metal, such as aluminum, and also form a whole with the extended part 10 of the cylinder 2. The piston rod 6 and the extended part 10 are further provided with openings 7 and 13 respectively with which the operating device 1 can be fixed between a fixed base and an object to be moved by the operating device 1.

The operating device 1 is further provided with means for locking the piston 3 in the cylinder 2 in the rest position. In the example shown, these blocking means are formed by a collapsing member arranged between the piston 3 and the cylinder, here in the form of a protruding breaking edge 17 of the piston 3, which is in engagement with a shoulder 18 in the cylinder 2.

The edge 17 is dimensioned such that it collapses when the gas pressure in the cylinder 2 behind the piston 3 is explosively increased by activating the pyrotechnic element 5.

The operating device 1 is also provided with means for fixing the piston 3 in the cylinder 2 at the end of its stroke movement. These fixing means are here formed by a tapered end part 20 of the cylinder, in which a conical end part 19 of the cylinder piston can be closely fitted. By a suitable choice of the material of the piston 3 and the cylinder 2, the piston 3 can be pressed by the gas pressure in the cylinder 2 with so much force into the tapered end 20 that the 7 piston 3 and the cylinder 2 act in the normal manner on them. taxes as a whole.

The cylinder 2 is otherwise provided with outflow openings 21 for escaping the air present in front of the piston 3 in the cylinder 2.

The operation of the operating device 1 is now as follows. When the operating device 1 is arranged by means of the attachment points 7 and 13 between a fixed base and an object to be moved, this in fact forms a rigid connection between them (Fig. 1A), due to the rigidity of the cylinder 2 and the extension part 10, and because the piston 3 is locked in the cylinder 2 by the fixation means 17, 18, and with its piston rod 6 locked in the extended part 10.

If the operating device 1 is now put into operation, the pyrotechnic element 5 is first activated by means of an igniter. As a result, a high gas pressure is built up explosively in the cylinder 2, as a result of which the piston 3 is moved to the right relative to the cylinder 2 in the drawing (Fig. 1B). The fixation edge 17 thereby collapses. The movement of the piston 3 in the cylinder 2 is limited by the tapered end 20 of the cylinder 2, in which the conical end 19 of the piston 3 becomes jammed. At that moment the distance between the attachment points 7 and 13 has increased with the stroke length of the piston 3, so that the object to be moved is displaced over the same stroke length.

If a reaction force is now exerted on the operating device 1 by the object to be moved, this force is initially absorbed by the damping means 14, which deform plastically in a precisely determined manner. The plastic deformation has the form of buckling the segments of the tube 15 between the stabilization rings 16, until parts of the inner wall of the tube 15 come into contact with each other and the tube segments are compressed substantially flat between the stabilization rings 16 (fig. 1C). Due to the specific shape of the damping means 14, the relationship between the plastic deformation thereof and the applied force is substantially linear, so that voltage spikes are avoided. The damping force increases rapidly at the start of the deformation, and then reaches a value that remains practically constant during the further deformation of the pipe segments.

Thus, in the operating device 1 according to this embodiment, a fast outgoing movement is combined with an even damping of a possible recoil movement. This makes the operating device 1 particularly suitable for use in certain safety systems, in particular systems used in vehicles to prevent personal injury in the event of a collision.

In a more compact variant of the operating device 1 (Fig. 2), the pyrotechnic element 5 is arranged in a space in a head part 4 connected to the cylinder wall 2, which at the same time carries a fixing point 13. An access space 22 for the ignition is also formed in the head part 4. In this variant, the damping means 14 are not included in the cylinder 2, but in the piston 3. To that end, the piston rod 6 is provided with a bore 24, in which an extension part 23 is received, which carries the fixing point 7. The damping means 14 also have the form of a sleeve 15 with a number of distributed stabilization rings 16, and are received in the bore 24 of the piston rod 6. The other parts of the operating device 1 correspond to those of the device of FIG. 1. When the operating device 1 according to this variant is used, gas pressure is built up by igniting the pyrotechnic element 5, as a result of which the piston 3 moves explosively to the left in the cylinder 2, and again locks in its end part, while during the subsequent occurrence of a larger reaction force the extension part 23 is pressed into the bore 24 of the piston rod 6, under compression of the damping means 14. These are again plastically deformed between the stabilizing rings 16, in the same manner as in Fig. 1.

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In a third variant of the operating device, the damping means 14 no longer have the shape of a sleeve with stabilizing rings, but are formed by plastically compressible bodies, such as, for example, plastic balls, received in the bore 24 of the piston rod 6. The end of the extension part 23 is in this case designed as an auxiliary piston 26, whereby the balls 25 are compressed. Incidentally, the plastically deformable balls 25 could also be replaced by a fluid that could be pressed through a small opening in the piston 3 or the wall of the piston rod 6, as a result of which a hydraulic damper would arise.

In yet another variant of the operating device 1 (Fig. 4), the movements relative to the previously shown variants are reversed, in the sense that a pull instead of a compressive force is exerted on the object to be moved, and thus the reaction force also an opposite tensile rather than compressive force. The damping of the reaction force is thereby provided by the piston rod 6, which is designed to be plastically deformable. In order to limit the movement of the piston rod, the end thereof is connected to the end wall 9 of the cylinder 2 via a compressible and extendable bellows 27.

As stated, the operating device 1 can be used in a safety system, for instance to move a vehicle seat 28, or at least its backrest 30 from back to front in the event of a collision, so as to prevent the distance between the back, neck and the user's head on the one hand and the backrest 30 and 30 headrest 36 of the seat 28 on the other hand becomes too large at the start of the collision, which could lead to forcefully striking these body parts in the backrest and headrest, turn could give rise to whiplash. Fig. 5 shows a conventional vehicle seat 28 with a seat 29 which is connected to the backrest 30 via an adjustable hinge 31.

The seat 28 stands on two seat rails 32 which are attached to the bottom 33 of the vehicle. In each rail 32 two slides 34 and 35 are slidably received, which support the chair 28.

According to an aspect of the invention, the desired movement of the backrest 30 is achieved by tilting the seat 29 and the backrest 30 connected thereto about an axis line P (Fig. 5B). In the example shown, this tilt axis line P is formed by a conventional hinge construction 37, with which the seat 29 is attached to the front carriage 34. For effecting the tilting movement, between the rear carriage 35 and a frame part 38 of the seat 28 comprises an operating device 1 as shown, for example, in one of the figures 1 to 3. This operating device 1 is activated in the case of a rear-end collision, which is detected by a sensor (not shown here). Upon activation, the piston 3 is moved relative to the cylinder 2, whereby the distance between the fixing points 7 and 13, one of which is connected to the carriage 35 and the other to the frame part 38, is increased. As a result, the seat 29, the backrest 30 and the headrest 36 are moved forward about the tilt axis P, whereby the distance between the backrest 30 and headrest 36 on the one hand and the back, neck and head of the user on the other hand is reduced.

It should be borne in mind here that as a result of the low stiffness of the seat, the backrest 30 and headrest 36 have started a rearward displacement immediately upon the occurrence of the collision, which is thus counteracted by the movement of the operating device. If subsequently the body of the user is also subjected to a rearward acceleration with some delay, and thus is pushed back into the backrest 30 and headrest 36, the forces occurring thereby will be relatively small, since the distance over which the body parts can accelerate before They hit the backrest and headrest relatively small. Thereafter, the force exerted by the user on the backrest and headrest increases, as a result of which the damping means 14 11 of the operating device 1 will deform plastically, and in this way an important part of the energy of the movement of the body relative to the chair is absorbed.

In an alternative embodiment of the seat 28 (Fig. 6), it is connected by two pivot arms 39, 40 to the slides 34 and 35. The slide 34 in this example is thereby driven by the operating device 1, while the second pivot arm 39 is formed. is moved by a separate damper, which in the example shown has the same structure as the damping means 14 in figures 1 and 2. When the operating device 1 is used in the event of a rear-end collision, the carriage 34 is thus moved forward, The front of the seat 29 is moved forward and downward by rotating the pivotal arm 39. As a result, the backrest 30 performs a combined translation and rotation movement in the direction of the back of the user. . When the user finally touches the backrest 30 and headrest 36, the resulting return movement of these parts and of the seat 30 is damped by plastic deformation of the damper acting as the second swivel arm 40.

In a third variant of the vehicle seat, two pivot arms 39 and 40 are connected to a common pivot point 41, while an operating device 1 with integrated damping means is connected to the point of engagement 38 of the second pivot arm 40 on the seat 28. Here too the activation of the operating device 1 in the first instance until a tilting movement of the chair 28 around the pivot point 41, whereby the distance between the backrest 30 and the headrest 36 on the one hand and the back, neck and the head of the user on the other hand is reduced, whereafter when the backrest and the headrest knock the body back and the chair is tilted backwards, while distorting the damping means in the operating device 1.

Finally, in Fig. 8, another variant of the seat 28 is shown, wherein use is made exclusively of a mechanical damper for damping the movement of the seat in response to a collision. from behind. This mechanical damper 14 has the same shape as the damping means in the embodiment of the operating device 1 of figures 1 and 2, that is to say a tubular shape with stabilizing rings, and is arranged between a front support 42 of the seat 28 and a fixed with the vehicle connected point.

Although the invention has been explained above with reference to a number of examples, it will be clear to the skilled person that it can be varied in many ways. The shape and dimensions of the cylinder and the piston can thus be selected differently, while the position of the pyrotechnic element can also be changed. The manner in which the piston is fixed in its rest position and / or in its end position with respect to the cylinder could also be varied. And although in most examples shown the operating device is combined with damping means, it could also be used without such damping means, or in combination with separate damping means. The position of the operating device when used in combination with a chair could also be varied. The operating device could thus directly engage the backrest or a part thereof, instead of the seat. The scope of the invention is therefore solely determined by the appended claims.

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Claims (17)

Operating device according to claim 1, characterized by means for blocking the piston in the cylinder in a rest position. 3. Operating device as claimed in claim 1 or 2, characterized in that the blocking means are formed by at least one collapsing member arranged between the piston and the cylinder. Operating device according to one of the preceding claims, characterized by means for fixing the piston in the cylinder at an end of its stroke movement. Operating device as claimed in claim 4, characterized in that the fixing means are formed by a tapered end part of the cylinder, and a conical end part of the piston that fits tightly therein. Operating device according to one of the preceding claims or according to the preamble of claim 1, characterized by means for damping a return movement thereof. 7. Operating device as claimed in claim 6, characterized in that the damping means are plastically deformable. Operating device as claimed in claim 7, characterized in that the cylinder and / or the piston is of partly designed form, and the damping means comprise at least one compressible damping member arranged between the parts. Operating device according to claim 8, characterized in that the damping member is box-shaped and has at least one protruding stabilizing edge. Operating device according to claim 9, characterized in that the tubular part of the damping member 35 and / or the stabilizing edge is made of metal. II. Operating device according to claim 8, characterized in that the damping member comprises at least one chamber filled with a compressible mass. 12. Operating device as claimed in claims 6 and 7, characterized in that the piston has a plastically extendable piston rod. 13. Seat, in particular vehicle seat, comprising a frame mounted in the vehicle, a seat mounted thereon and a backrest connected thereto, at least a part of which is movable substantially parallel to the seat, characterized by at least one operating device for adjusting response to an impact load with the load moving at least the movable part of the backrest. 14. Seat as claimed in claim 13, characterized in that the seat and / or backrest can be tilted about a horizontal axis directed substantially transversely to the direction of movement of the vehicle. 15. Chair as claimed in claim 14, characterized in that the tilt-axis line is determined by at least one hinge placed near an edge of the seat remote from the backrest. 16. Seat as claimed in claim 14 or 15, characterized in that the seat and / or backrest is connected to the frame by at least two pivot arms arranged in the direction of movement of the vehicle with spacing. Chair according to one of claims 13 to 16, characterized in that the at least one operating device is arranged between the seat and / or backrest and the frame. Chair according to any one of claims 13 to 17, characterized by separate means arranged between the seat and / or backrest and the frame for damping a return movement of the seat and / or backrest. 19. A damping member, apparently intended for use in an operating device according to any one of claims 8 to 11. 0; > 3