Safety device for a height-adjustable seat structure and vehicle seat in a truck, work or bus using such a safety device

Abstract

A safety device for a height adjustable seat structure (100) is provided. The seat structure includes a first set of legs (101A) including a first leg (105A) pivotally connected to a second leg (108A) and a first pair of rails (102A) including an upper rail (103A) and a lower rail (104A). The first leg includes one end portion (106A) pivotally hinged to the upper rail and another end portion (107A) linearly movable along the lower rail. The second leg includes one end portion (109A) pivotally hinged to the lower rail and another end portion (110A) linearly movable along the upper rail. The seat structure further includes a first seat actuator (200) including a first piston (202), the first seat actuator configured to move the first piston from a retracted position to an extended position in which the first piston is configured to move the first piston from the retracted position to the extended position in accordance with an activation signal, the first piston being configured to move the first piston from the retracted position to the extended position in accordance with the activation signal. The first piston directly or indirectly applies a force to one of the linearly movable end portions to urge the height adjustable seat structure toward the lowered position. In addition, a vehicle seat provided with such a safety device is disclosed.

Description

Technical Field

[0001] The present invention relates to a safety device for a height - adjustable seat structure and to a vehicle seat in a truck, lorry or bus using such a safety device. Background Art

[0002] Seats for trucks, lorries and buses should be comfortable in order to provide an ergonomic and comfortable working environment for the driver / passenger. By way of example, the seat should provide a wide range of settings and also provide good suspension. A well - known measure for allowing height adjustment of a vehicle seat is to use a scissor mechanism to provide a seat - lifting device for its seat structure. Such seat structures inherently have weaknesses and tend to deform and bend forward in the case of a frontal collision. One way to reduce and limit movement in the case of a frontal collision is to provide a seat belt and a seat belt retractor that restricts the forward movement of the seat structure. Such seat belt retractors can be of the same type as those used in conventional seat belts. However, seat belts typically require a certain amount of slack to allow the seated person to adjust the seat in the vertical direction as well as in the backward and forward directions. However, such slack is dangerous in the case of a roll - over accident. In a roll - over accident, the seat structure as well as the body of the seated person attached to the seat will undergo upward and lateral movement. While the movement of the seat structure can be restricted by the seat belt and the seat belt retractor, the movement of the body can be restricted by the seat belt and one or more air bags configured to deploy in the opposite direction. However, there remains a risk that, in particular, the head of the seated person comes into contact with a cross - bar extending between the A - pillar and the B - pillar of the vehicle cab. This is because the body is not fully connected by the seat belt in this direction. This is especially the case when the seat has been set to a vertically elevated position, where the vertical distance between the person's head and the cross - bar of the vehicle cab is short. Accordingly, there is a need to provide an improved safety device for a seat intended for use in a truck, lorry or bus, which device is designed to operate in the case of a roll - over accident. Summary of the Invention

[0003] An object of the present invention is to provide a safety device for a height - adjustable seat structure, which safety device is designed to override any adjustment in the height direction set by the driver / passenger.

[0004] Another object is to provide a safety device that can be released in the event of a determined roll - over accident.

[0005] Yet another object is to provide a safety device that is specifically designed for a seat structure in a vehicle seat in a truck, lorry or bus and in similar vehicles using a scissor mechanism.

[0006] These and other objects, which are apparent from the following summary and description, are achieved by a safety device according to the appended claims.

[0007] According to one aspect of the invention, there is provided a safety device for a height - adjustable seat structure, the seat structure comprising: a first set of legs and a first pair of guide rails, the first set of legs including a first leg pivotally connected to a second leg, the first pair of guide rails including an upper guide rail and a lower guide rail; wherein

[0008] the first leg of the first set of legs includes an end portion pivotally hinged to the upper guide rail of the first pair of guide rails and another end portion linearly movable along the lower guide rail of the first pair of guide rails, and the second leg of the first set of legs includes an end portion pivotally hinged to the lower guide rail of the first pair of guide rails and another end portion linearly movable along the upper guide rail of the first pair of guide rails; wherein

[0009] the height - adjustable seat structure further includes a first seat actuator including a first piston, the first seat actuator being configured to move the first piston from a retracted position to an extended position in accordance with an activation signal, in which extended position, the first piston directly or indirectly applies a force to one of the end portions of the first set of legs that is linearly movable, thereby pushing the height - adjustable seat structure towards a lowered position.

[0010] Thus, there is provided a safety device arranged to interact with a seat structure of the type using a scissor mechanism to allow the seat structure to be height - adjustable. Such seat structures are well - known in seats for trucks and vans. More precisely, the safety device according to the invention includes a seat actuator having a piston which, when set to its extended position, directly or indirectly applies a force to one of the end portions of the first set of legs that is linearly movable. The height - adjustable seat structure is thereby pushed by the piston towards a lowered position. The body of the person sitting and connected thereto will thus automatically follow the downward direction as she is connected to the vehicle seat using a three - point seat belt. As the body of the person moves downward, her head portion will be prevented from hitting the crossbar extending between the A - pillar and the B - pillar of the vehicle cab. Instead, the lateral movement of her head can be accommodated by an airbag forming part of the overall vehicle crash protection system, and the airbag is configured to deploy in both the downward and lateral directions.

[0011] Due to the scissors mechanism, the piston can be configured to act on either of the two linearly movable end portions of the first set of legs to lower the seat structure. The piston can be configured to act directly on the legs by physically engaging the legs with the free end of the piston (or a driver connected thereto), or indirectly on the legs by engaging, for example, a protrusion or crossbar connected to the legs with the free end of the piston (or a driver connected thereto). The activation signal can be communicated from a collision sensor in response to a determined rollover accident. The activation signal can be communicated to the seat actuator via a processor forming part of an electronic control unit (ECU) of the vehicle.

[0012] The seat structure may further include a second set of legs and a second pair of guide rails, the second set of legs including a first leg pivotally connected to a second leg, the second pair of guide rails including an upper guide rail and a lower guide rail; wherein the first leg of the second set of legs includes one end portion pivotally hinged to the upper guide rail of the second pair of guide rails and another end portion linearly movable along the lower guide rail of the second pair of guide rails, and the second leg of the second set of legs includes one end portion pivotally hinged to the lower guide rail of the second pair of guide rails and another end portion linearly movable along the upper guide rail of the second pair of guide rails.

[0013] Although the seat structure in its simplest form may include only one set of legs, a more robust seat structure can be provided by providing two sets of legs. The first set of legs and the second set of legs of the seat structure are preferably arranged side by side in a parallel manner. The first set of legs and the second set of legs are preferably identical.

[0014] The safety device may further include a second seat actuator including a second piston, the second seat actuator being configured to move the second piston from a retracted position to an extended position in accordance with the activation signal, in which extended position the second piston directly or indirectly applies a force to one of the linearly movable end portions of the first set of legs and / or the second set of legs.

[0015] Thus, the first seat actuator and the second seat actuator can be arranged to act on the same set of legs or different sets of legs. The two seat actuators can be fixedly connected to the upper guide rail or the lower guide rail of the first pair of guide rails, to the upper guide rails of the first pair of guide rails and the second pair of guide rails, or to the lower guide rails of the first pair of guide rails and the second pair of guide rails. The first seat actuator and the second seat actuator should preferably be arranged symmetrically.

[0016] The first seat actuator and the second seat actuator can be configured to be simultaneously activated by one and the same activation signal.

[0017] The first set of legs and the second set of legs may be interconnected by at least one crossbar that extends perpendicular to the longitudinal extensions of the guide rails in the first pair of guide rails and the second pair of guide rails.

[0018] The seat actuator may be fixedly connected to the upper guide rail or the lower guide rail in the first pair of guide rails, or to the upper guide rail or the lower guide rail in the first pair of guide rails and the second pair of guide rails.

[0019] By way of example, the guide rails may have an L-shaped cross-section or a C-shaped cross-section. The seat actuator is preferably arranged on the inner wall portion of the guide rail.

[0020] The corresponding piston may be configured to move in a direction parallel to the longitudinal extension of the upper guide rail or the lower guide rail in the corresponding pair of guide rails.

[0021] The corresponding piston may be configured to apply a force to one of the linearly movable end portions of the corresponding set of legs by directly acting on one of the first leg and the second leg in the corresponding set of legs, or indirectly by acting on a protrusion or a crossbar mounted on one of the first leg and the second leg in the corresponding set of legs.

[0022] The seat structure may further include a seat support having a top surface and a bottom surface, wherein the upper guide rail in the corresponding pair of guide rails is supported by the bottom surface of the seat support.

[0023] The corresponding seat actuator may be fixedly connected to the seat support. The fixing may be carried out by bolt connection or welding.

[0024] In one embodiment, the seat actuator may be arranged along the longitudinal center line of the seat support, and the piston of the seat actuator may be configured to apply a force to the linearly movable end portions of the first set of legs and the second set of legs simultaneously, directly or indirectly.

[0025] This may be achieved by the free end of the piston, which includes a driver in the form of a crossbar having a lateral extension located between the first leg and the second leg, so as to allow the two sets of legs to be directly and simultaneously acted upon.

[0026] Alternatively, this may be achieved by the free end of the piston, which includes a driver configured to act on a crossbar that extends between the two sets of legs, so as to allow the two sets of legs to be indirectly and simultaneously acted upon.

[0027] The piston of the corresponding seat actuator may be configured to be actuated by the gas pressure generated by a gas generator. The gas generator may be a pyrotechnic gas generator.

[0028] The dimensions of the seat actuator can be set to apply a force to the seat structure that has a vertical force component exceeding the vertical force component exerted by any seat-lifting device integrated in the seat structure. Such seat-lifting devices are typically part of the comfort device of the seat structure to allow the seated person to adjust the height and suspension of the seat structure. By way of example, such seat-lifting devices can be gas springs that interact with one or two sets of legs of the seat structure. The force of the seat actuator set to a dimension should exceed the vertical force exerted by any seat-lifting device integrated in the seat structure so as to overturn this vertical force and push the seat structure to a lowered position in the event of a defined rollover accident.

[0029] The free end of the corresponding piston may include a driver having a C-shaped or V-shaped form. By the C-shaped or V-shaped form, the driver will facilitate engagement with the legs or any protrusion or crossbar extending from the guide rail and also accommodate any deformation of the seat structure.

[0030] According to another aspect, the present invention refers to a vehicle seat in a truck, bus or lorry, characterized in that the vehicle seat is provided with a safety device according to any one of claims 1 to 13. The features and advantages of such safety devices have been discussed above. These equally apply to the vehicle seat using such safety devices and, to avoid undue repetition, reference is made to the above sections.

[0031] Other objects and advantages of the present invention will be apparent to those skilled in the art by reading the detailed description given below of different embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will be described in detail with reference to the schematic drawings.

[0033] Figure 1 An embodiment of a vehicle seat with a height-adjustable seat structure using a scissor mechanism is disclosed.

[0034] Figure 2 It is schematically disclosed how the legs of the scissor mechanism move during the lowering of the seat structure.

[0035] Figure 3 A vehicle seat having a first embodiment of a safety device according to the present invention is disclosed.

[0036] Figure 4A and Figure 4B It is schematically disclosed the operation of the safety device according to the first embodiment of the present invention.

[0037] Figure 5 A vehicle seat having a second embodiment of a safety device according to the present invention is disclosed.

[0038] Figure 6A and Figure 6B schematically discloses the operation of a safety device according to a second embodiment of the present invention.

[0039] Figure 7A and Figure 7B schematically discloses the operation of a safety device according to a third embodiment of the present invention.

[0040] Figures 8A to 8E Highly schematically discloses different embodiments of using two or more seat actuators as applied to a seat structure.

[0041] Figure 9 Highly schematically discloses an alternative form of a centrally arranged seat actuator. Detailed Description

[0042] Now turning to Figure 1 and Figure 2 , an example of a vehicle seat 1 is disclosed. The vehicle seat 1 is of the type commonly used in trucks, vans or buses. The vehicle seat 1 includes a height-adjustable seat structure 100 using a scissor mechanism. The disclosed seat structure 100 includes a first set of legs 101A and a second set of legs 101B pivotally interconnected by a crossbar 112. The two sets of legs are arranged in parallel, whereby only one set of legs is disclosed in the view shown.

[0043] The crossbar 112 provides stability, but in view of the legs in each set of legs 101A, 101B, the crossbar also serves as pivots 111A, 111B. Although the seat structure 100 in its simplest form may include only one set of legs, a more robust seat structure can be provided by providing two sets of legs. The first set of legs 101A and the second set of legs 101B are preferably arranged side by side in a parallel manner.

[0044] In addition, the disclosed seat structure 100 includes a first pair of guide rails 102A and a second pair of guide rails 102B. The two pairs of guide rails are arranged in parallel, whereby only one set of legs is disclosed in the view shown.

[0045] Each pair of guide rails 102A, 102B includes an upper guide rail 103A, 103B and a lower guide rail 104A, 104B. Those skilled in the art will recognize that in the case of only one set of legs, only one pair of guide rails is required.

[0046] The two sets of legs 101A, 101B and the two pairs of guide rails 102A, 102B are preferably identical. Unless otherwise specifically stated, only the first set of legs 101A and the first pair of guide rails 102A will be referred to below. Figure 2 for discussion.

[0047] Go to Figure 2 The first leg 105A in the first set of legs 101A includes an end portion 106A that is pivotally hinged to the upper rail 103A in the first pair of rails 102A, see arrow A1. Another end portion 107A of the first leg 105A is linearly movable along the lower rail 104A in the first pair of rails 102A, see arrow A2.

[0048] Correspondingly, the second leg 108A in the first set of legs 101A includes an end portion 109A that is pivotally hinged to the lower rail 104A in the first pair of rails 102A, see arrow A3. Another end portion 110A is linearly movable along the upper rail 103A in the first pair of rails 102A, see arrow A4. With this arrangement, the first set of legs 101A operates like a scissor mechanism, which allows the height of the seat structure 100 to be adjustable by pivoting each leg 105A, 108A relative to its corresponding rail 103A, 104A and also by pivoting the two legs 105A, 108A relative to each other about the pivot 111A, see arrow B.

[0049] By way of example, the rails 103A, 104A can have a C-shaped cross-section or an L-shaped cross-section. It should be appreciated that other cross-sections are also applicable.

[0050] The lower rails 104A, 104B can be fixedly mounted directly to the floor of the vehicle cab (not shown). They can also be fixed to a structure (not shown) that is in turn configured to be fixedly mounted to the cab floor.

[0051] The end portions 107A, 110A of the legs that are linearly movable along the corresponding rails 103A, 104A can be provided with optional sliding members, such as wheels (not shown), which provide low-friction support relative to the rails. As an alternative to wheels, the free ends of the corresponding legs can be provided with rounded end profiles, protective sheets or protective plugs. The sheet or plug can be formed of a low-friction material.

[0052] The first set of legs 101A and the second set of legs 101B are interconnected by at least one crossbar 112. In the disclosed embodiment, five crossbars 112 are disclosed. The crossbars 112 extend perpendicular to the longitudinal extensions of the rails 103A, 103B, 104A, 104B in the first pair of rails 102A and the second pair of rails 102B.

[0053] As Figure 1As best shown, the seat structure 100 may further include a seat support member 113. The seat support member 113 has a top surface and a bottom surface. The top surface supports the seat cushion 114. The upper guide rails 103A, 103B of the corresponding pair of guide rails 102A, 102B are supported by the bottom surface of the seat support member 113. The upper guide rails 103A, 103B can be mounted to the seat support member 113 by, for example, bolt connection or welding.

[0054] The seat structure 100 further includes a seat lifting device 115. The seat lifting device 115 is shown highly schematically. The seat lifting device 115 (which is well known in the art per se) is generally part of the comfort device of the seat structure 100 to allow adjustment of the height and suspension of the seat structure 100. By way of example, the seat lifting device 115 can be a gas spring 116 that cooperates with the guide rails of the seat structure 100. The position and structural design of the seat lifting device 115 may vary between different seat suppliers and vehicles.

[0055] Now turning to Figure 3 , a first embodiment of the safety device according to the present invention is disclosed as being mounted to the seat structure 100 of a vehicle seat 1.

[0056] The safety device includes a seat actuator 200. The seat actuator 200 is disclosed as being fixedly connected to an inner wall portion of one of the two upper guide rails 103B by a bracket 201. By arranging the seat actuator on the inner wall portion and thus on the lower side of the vehicle seat 1, the seat actuator 200 will be protected from any external impact and / or interference. Regardless of the position, the fixation can be carried out by bolt connection or welding.

[0057] It should be emphasized that a second seat actuator may optionally be arranged in a corresponding position on the inner wall of the other upper guide rail 103A of the two parallel upper guide rails. Hereinafter, only one of the two actuators will be discussed, since the design and operating principles are the same.

[0058] The seat actuator 200 includes a piston 202. The piston 202 is arranged in a housing 203 that forms a cylinder chamber. The cylinder chamber serves as a guide for the piston 202 during its actuation. The piston 202 is Figure 3 disclosed as being in its retracted position, i.e., its normal position. As will be discussed below, the piston 202 is configured to longitudinally shift to its extended position when the seat actuator 200 is activated. This activation can be triggered by an activation signal from a collision sensor (not shown) that indicates an accident of the rollover type.

[0059] The piston 202 is in its simplest form configured as a rod. In some embodiments, the piston 202 can be telescopic. The piston 202 can be configured to be actuated by the gas pressure generated by a gas generator (not shown) in the seat actuator 200. The gas generator can be a pyrotechnic gas generator. This is well known in the art and will not be discussed further.

[0060] The housing 203 of the seat actuator 200 can have a discharge device (not shown) that allows the generated gas to be discharged from the housing 203. Such discharge is well known in the art and will not be discussed further.

[0061] The free end of the piston 202 includes an optional driver 204. The driver 204 can have a C-shaped or V-shaped configuration. The driver 204 is disclosed as being configured to engage a protruding portion of the crossbar 112 that pivotally interconnects the upper portions of the two legs 105A, 105B and that can linearly move the end portions 110A, 110B. Those skilled in the art will recognize that the driver can be omitted. Instead, the free end of the piston 202 can be configured to act directly on the corresponding linearly movable leg.

[0062] The piston 202 is preferably configured to move in a direction parallel to the longitudinal extension of at least one of the guide rails 104A, 104B; 103A, 103B of the pair of guide rails 102A, 102B.

[0063] Now turning to Figure 4A and Figure 4B , the operation of the safety device according to the first embodiment will be discussed.

[0064] Starting from Figure 4A , the seat actuator 200 in its normal use is disclosed, where the seat actuator 200 is fixedly supported on the inner wall of one of the upper guide rails 103B of the seat structure 100. Additionally, the piston 202 is in its retracted position. Preferably, the seat actuator 200 is installed such that when the seat structure 100 is set to its highest position allowed when using the seat lifting device, there is a gap G between the driver 204 of the piston 202 and the linearly movable end portion of the leg to be acted upon or the crossbar 112, as seen in the proper position. Thus, during the normal use of the vehicle seat (such as in the case of a bumpy road), there is no risk that the driver 204 or the free end of the piston 202 will be accidentally forced to engage with the leg / crossbar.

[0065] When a rollover accident is determined by a collision sensor (not shown) in a vehicle, an activation signal is communicated from the collision sensor to the seat actuator 200 via a processor (not shown) forming part of the vehicle's electronic control unit (ECU). The gas generator is activated, thereby creating gas pressure inside the housing 203 of the seat actuator 200. The gas pressure forces the piston 202 to move from its retracted position to its extended position, see Figure 4B . In cases where the safety device includes two seat actuators, these seat actuators can be configured to be activated simultaneously by one and the same activation signal.

[0066] When the piston 202 moves from its retracted position to its extended position, the driver 204 on the free end of the piston 202 contacts, according to the design, the crossbar 112 or the linearly movable end portion 110B of the leg. Depending on the design of the end portion 110B of the leg, the driver 204 can directly engage the end portion, or engage a protrusion or crossbar that extends from or extends through the linearly movable end portion of the leg. The piston 202 thus applies a linear force to the linearly movable upper end portion 110B of the leg. The height-adjustable seat structure 100 is thereby pushed towards its lowered position, see Figure 4B . The lowering of the seat structure 100 is the result of the scissor mechanism of the seat structure. The movement of the seat structure 100 is shown by the arrows in Figure 4A .

[0067] The body of the person sitting and strapped in will automatically follow the downward direction since she is strapped to the vehicle seat using a three-point seat belt. Since the body of the person moves downward, her head portion will be prevented from hitting the crossbar structure extending between the A-pillar and the B-pillar of the vehicle cab. Instead, the lateral movement of her head can be accommodated by an airbag forming part of the overall vehicle collision protection system, and the airbag is configured to deploy in the downward and lateral directions.

[0068] The seat actuator 200 is dimensioned to apply a force to the seat structure 100 that has a vertical force component exceeding the vertical force component applied by any seat lifting device integrated in the seat structure 100. The seat lifting device is omitted in Figure 3 and Figures 4A to 4B . See Figure 1, the seat lift device 115 is generally part of the comfort device of the seat structure 100 to allow the seated person to adjust the height and suspension of the seat structure 100. By way of example, such a seat lift device can be a gas spring that interacts with one or two sets of legs of the seat structure 100. By sizing the vertical force component of the impact force applied by the seat actuator 200 to exceed the vertical force component applied by any seat lift device, the latter will be overridden and the seat structure 100 will be pushed to its lowered position and thus be pushed to Figure 4B the position disclosed in

[0069] Now turning to Figure 5 , a second embodiment of the safety device according to the present invention is disclosed as being mounted to the seat structure 100 of the vehicle seat 1.

[0070] The second embodiment differs from the first embodiment in that the seat actuator 200 is fixed to the inner wall portion of the lower guide rail 104B.

[0071] It should be emphasized that the second seat actuator 200 can optionally be arranged in a corresponding position on the inner wall of the other lower guide rail 104A of the two parallel lower guide rails 104A, 104B. Hereinafter, only one of the two actuators will be discussed, since the design and operating principles are the same.

[0072] The operating principle of the second embodiment is disclosed in Figure 6A and Figure 6B . Figure 6A The safety device in its normal use is disclosed, where the piston 202 is in its retracted position and the seat structure is set to the raised position. Figure 6B The safety device in its activated position is disclosed, where the piston 202 has been set to its extended position, and where the piston of the seat actuator has pushed the seat structure 100 to its lowered position. The movement of the seat structure 100 is shown by the arrow. The operating principle is the same as that discussed above with reference to Figure 3 and Figures 4A to 4B . Refer to the above discussion to avoid excessive repetition.

[0073] Now turning to FIGS. 7a and Figure 7B , a third embodiment of the safety device according to the present invention is disclosed as being mounted to the seat structure 100 of the vehicle seat 1. The third embodiment differs from the first and second embodiments in that the seat actuator 200 is fixed to the support structure 300, which is directly or indirectly fixedly mounted to the floor of the vehicle cab. The overall design of the seat structure 100 and the vehicle seat 1 is the same as that described above with reference to Figure 1 and Figure 2 .

[0074] In this embodiment, the seat actuator 200 is arranged along the longitudinal centerline of the seat support. The piston 202 of the seat actuator 200 is configured to simultaneously and indirectly apply a force to the linearly movable end portions of the first set of legs 101A and the second set of legs 101B. This is achieved by the free end of the piston 202, which includes a driver 204 configured to act on the central position of a crossbar 112 that extends between the two sets of legs 101A, 101B. Thereby, the two sets of legs can act simultaneously to lower the seat structure 100.

[0075] The seat actuator 200 is disclosed as being arranged to act on a crossbar 112 that extends between two linearly movable end portions 107A, 107B supported by two lower guide rails 104A, 104B. Those skilled in the art will recognize that the same principle applies equally by alternatively arranging the seat actuator to be supported by the bottom surface of the seat structure 113 and arranging the piston to act on an upper crossbar that extends between two linearly movable end portions 108A, 108B supported by two upper guide rails 103A, 103B.

[0076] Similar to the first and second embodiments, the free end of the piston 202 includes an optional driver 204 having a C-shaped configuration.

[0077] Figure 7A A safety device in its normal use is disclosed, in which the piston 202 is in its retracted position and the seat structure 100 is set to the raised position. Preferably, the seat actuator 200 is mounted such that when the seat structure 100 is set to the highest position allowed when using the seat lifting device, there is a gap G between the driver 204 of the piston 202 and the crossbar 112 to be acted upon, as seen in the proper position. Thereby, during the normal use of the vehicle seat (such as in the case of a bumpy road), there is no risk that the driver 204 of the piston 202 will be accidentally forced to engage with the crossbar 112.

[0078] Figure 7B A safety device in its activated position is disclosed, in which the piston 202 has been set to its extended position, and in which the piston 202 of the seat actuator 200 has pushed the seat structure 100 to its lowered position. The operating principle is the same as that discussed above with reference to Figure 3 and Figures 4A to 4B discussed, and will not be further discussed to avoid excessive repetition.

[0079] The number of seat actuators can be varied. In its simplest form, as already illustrated above with reference to the first to third embodiments, having a single seat actuator suffices. It has been illustrated that such a single seat actuator can be fixedly connected to the upper or lower guide rail in one of a pair of guide rails. In the case of two or more seat actuators, these seat actuators are preferably arranged symmetrically. In the case where the safety device includes two or more seat actuators, these seat actuators can be configured to be simultaneously activated by one and the same activation signal.

[0080] Figure 8A One embodiment is disclosed having two seat actuators 200 in the upper guide rail 103A and the lower guide rail 104A of the first pair of guide rails.

[0081] Figure 8B One embodiment is disclosed having two seat actuators 200 in the upper guide rail 103B and the lower guide rail 14B of the second pair of guide rails.

[0082] Figure 8C One embodiment is disclosed having two seat actuators 200 in two upper guide rails 103A, 103B.

[0083] Figure 8D One embodiment is disclosed having two seat actuators 200 in two lower guide rails 104A, 104B.

[0084] Figure 8E One embodiment is disclosed having four seat actuators 200, one seat actuator in each of the guide rails 103A, 103B, 104A, 104B.

[0085] Now turning to Figure 9 . Those skilled in the art will recognize that by providing a T-shaped crossbar 212 with a driver 204' in its free end for the free end of such a centered piston 202, the same principle as in the third embodiment can be provided. The T-shaped crossbar 212 has a lateral extension that is configured to extend between the first and second legs of the first set of legs and the second set of legs, thereby allowing the two sets of legs to be directly and simultaneously acted upon.

[0086] Those skilled in the art will recognize that the features from the various embodiments disclosed herein can be combined with one another to provide additional alternative embodiments.

[0087] A seat structure has been disclosed, in which the seat structure and the seat actuator are oriented such that the end portion of the leg that can move linearly is arranged to move in a rearward position to lower the seat structure. Those skilled in the art recognize that the seat structure and its seat actuator with remaining functions can be oriented in the opposite direction, rather than being configured to operate in the forward direction to lower the seat structure.

[0088] The safety device can be combined with any additional separate restraint system (not shown). These systems can be configured to be enabled simultaneously.

Claims

1. A safety device for a height-adjustable seat structure, the seat structure comprising: A first set of legs and a first pair of guide rails, wherein the first set of legs includes a first leg pivotally connected to a second leg, and the first pair of guide rails includes an upper guide rail and a lower guide rail; wherein the first leg of the first set of legs includes an end portion pivotally hinged to the upper guide rail of the first pair of guide rails and another end portion linearly movable along the lower guide rail of the first pair of guide rails, and the second leg of the first set of legs includes an end portion pivotally hinged to the lower guide rail of the first pair of guide rails and another end portion linearly movable along the upper guide rail of the first pair of guide rails; wherein the height - adjustable seat structure further includes a first seat actuator, the first seat actuator includes a first piston, and the first seat actuator is configured to move the first piston from a retracted position to an extended position according to an activation signal, and in the extended position, the first piston directly or indirectly applies a force to one of the linearly movable end portions of the first set of legs that is linearly movable, thereby pushing the height - adjustable seat structure toward a lowered position.

2. The safety device according to claim 1, wherein the seat structure further includes a second set of legs and a second pair of guide rails, the second set of legs includes a first leg pivotally connected to a second leg, and the second pair of guide rails includes an upper guide rail and a lower guide rail; wherein the first leg of the second set of legs includes an end portion pivotally hinged to the upper guide rail of the second pair of guide rails and another end portion linearly movable along the lower guide rail of the second pair of guide rails, and the second leg of the second set of legs includes an end portion pivotally hinged to the lower guide rail of the second pair of guide rails and another end portion linearly movable along the upper guide rail of the second pair of guide rails.

3. The safety device according to claim 1 or 2, wherein the safety device further includes a second seat actuator, the second seat actuator includes a second piston, and the second seat actuator is configured to move the second piston from a retracted position to an extended position according to an activation signal, and in the extended position, the second piston directly or indirectly applies a force to one of the linearly movable end portions of the first set of legs and / or the second set of legs that is linearly movable.

4. The safety device according to claim 3, wherein the first seat actuator and the second seat actuator are configured to be simultaneously activated by one and the same activation signal.

5. The safety device according to claim 3, wherein the first set of legs and the second set of legs are interconnected by at least one crossbar extending perpendicularly to the longitudinal extensions of the guide rails in the first pair of guide rails and the second pair of guide rails.

6. The safety device according to claim 1 or 2, wherein the seat actuator is fixedly connected to the upper rail or the lower rail of the first pair of rails, or to the upper rail or the lower rail of the first pair of rails and the second pair of rails.

7. The safety device according to claim 1 or 3, wherein the respective piston is configured to move in a direction parallel to the longitudinal extension of the upper rail or the lower rail of the respective pair of rails.

8. The safety device according to claim 1 or 3, wherein the respective piston is configured to apply a force to one of the linearly movable end portions of the respective set of legs by directly acting on one of the first leg and the second leg in the respective set of legs, or to indirectly apply a force by acting on a protrusion or crossbar mounted on one of the first leg and the second leg in the respective set of legs.

9. The safety device according to claim 1, wherein the seat structure further includes a seat support having a top surface and a bottom surface, and wherein the upper rail of the respective pair of rails is supported by the bottom surface of the seat support.

10. The safety device according to claim 9, wherein the seat actuator is arranged along the longitudinal centerline of the seat support, and wherein the piston of the seat actuator is configured to simultaneously, directly or indirectly apply a force to the linearly movable end portions of the first set of legs and the second set of legs.

11. The safety device according to claim 1 or 3, wherein the piston of the respective seat actuator is configured to be actuated by the gas pressure generated by a gas generator.

12. The safety device according to claim 1, wherein the seat actuator is sized to apply a force to the seat structure, the force having a vertical force component that exceeds the vertical force component applied by any seat lifting device integrated in the seat structure.

13. The safety device according to claim 1, wherein the free end of the respective piston includes a driver having a C-shaped or V-shaped configuration.

14. A vehicle seat in a truck, bus or lorry, the vehicle seat being provided with the safety device according to claim 1.

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