VEHICLE SEAT AND A METHOD FOR OPERATING A VEHICLE SEAT

Abstract

A vehicle seat includes a lower frame and an upper frame, where the upper frame is pivotably arranged in relation to the lower frame. The upper frame is movably connected to the lower frame via an actuating assembly, where the actuating assembly includes a first actuator and a second actuator configured to cooperate with each other for displacing the upper frame in relation to the lower frame. The actuating assembly further includes a beam structure connected to and extending between the first actuator and the second actuator, where the first actuator and the second actuator are floatingly connected to the lower frame via the beam structure.

Claims

1. A vehicle seat comprising a lower frame and an upper frame, wherein the upper frame is pivotably arranged in relation to the lower frame, wherein the upper frame is movably connected to the lower frame via an actuating assembly, wherein the actuating assembly comprises a first actuator and a second actuator configured to cooperate with each other for displacing the upper frame in relation to the lower frame, wherein the actuating assembly further comprises a beam structure connected to and extending between the first actuator and the second actuator, wherein the first actuator and the second actuator are floatingly connected to the lower frame via the beam structure.

2. The vehicle seat according to claim 1, wherein the first actuator comprises a first drive unit attached to the beam structure, wherein the first drive unit is floatingly connected to the lower frame via the beam structure; wherein the second actuator comprises a second drive unit attached to the beam structure, wherein the second drive unit is floatingly connected to the lower frame via the beam structure.

3. The vehicle seat according to claim 2, wherein the first actuator comprises a first displacement member rotatably connected to the beam structure, wherein the first drive unit is connected to the first displacement member and configured for rotating the first displacement member when displacing the upper frame in relation to the lower frame; wherein the second actuator comprises a second displacement member rotatably connected to the beam structure, wherein the second drive unit is connected to the second displacement member and configured for rotating the second displacement member when displacing the upper frame in relation to the lower frame.

4. The vehicle seat according to claim 3, wherein the first drive unit and the second drive unit are synchronized electric motors.

5. The vehicle seat according to claim 3, wherein the first displacement member is connected to the upper frame via a first pivoting member and the second displacement member is connected to the upper frame via a second pivoting member, wherein the first pivoting member and the second pivoting member are pivotably connected to the upper frame.

6. The vehicle seat according to claim 5, wherein the first displacement member is rotatably connected to the first pivoting member and the second displacement member is rotatably connected to the second pivoting member, wherein the first displacement member is configured for displacing the upper frame in relation to the lower frame upon rotation of the first displacement member, wherein the second displacement member is configured for displacing the upper frame in relation to the lower frame upon rotation of the second displacement member.

7. The vehicle seat according to claim 5, wherein the first displacement member is arranged as a threaded screw having an extension in a first axial direction and a first threaded section, wherein the first pivoting member comprises a first threaded opening configured for engaging the first threaded section, wherein upon rotation of the first displacement member the first pivoting member is displaced along the first displacement member in the first axial direction; wherein the second displacement member is arranged as a threaded screw having an extension in a second axial direction and a second threaded section, wherein the second pivoting member comprises a second threaded opening configured for engaging the second threaded section, wherein upon rotation of the second displacement member the second pivoting member is displaced along the second displacement member in the second axial direction.

8. The vehicle seat according to claim 1, wherein the first pivoting member and the second pivoting member are connected to a beam member of the upper frame, wherein the beam member is extending in a lateral direction.

9. The vehicle seat according to claim 1, wherein the beam structure is slidingly arranged relative to a cradle structure of the lower frame, wherein upon displacement of the upper frame in relation to the lower frame the beam structure is sliding relative to the cradle structure.

10. The vehicle seat according to claim 9, wherein the cradle structure is extending in a lateral direction.

11. The vehicle seat according to claim 3, wherein the first displacement member and the second displacement member are extending through the cradle structure.

12. The vehicle seat according to claim 11, wherein the beam structure comprises a first structural element arranged in connection to a lower end of the first displacement member and a second structural element arranged in connection to a lower end of the second displacement member, wherein the first structural element and the second structural element are arranged below the cradle structure and configured for preventing upward movements of the first displacement member and the second displacement member in a vehicle impact event.

13. The vehicle seat according to claim 1, wherein a front part of the upper frame is pivotably arranged in relation to a front part of the lower frame around a front pivot axis.

14. The vehicle seat according to claim 1, wherein a rear part of the upper frame is movably connected to a rear part of the lower frame via the actuating assembly.

15. The vehicle seat according to claim 1, wherein the first actuator is arranged in connection to a first rear lateral side of the lower frame, and the second actuator is arranged in connection to a second rear lateral side of the lower frame.

16. A method for operating a vehicle seat, wherein the vehicle seat comprises a lower frame and an upper frame, wherein the upper frame is pivotably arranged in relation to the lower frame, wherein the upper frame is movably connected to the lower frame via an actuating assembly, wherein the actuating assembly comprises a first actuator, a second actuator, and a beam structure connected to and extending between the first actuator and the second actuator, wherein the first actuator and the second actuator are floatingly connected to the lower frame via the beam structure, wherein the method comprises the step: operating the first actuator and the second actuator, wherein the first actuator and the second actuator upon operation are cooperating for displacing the upper frame in relation to the lower frame.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The disclosure will be described in detail in the following, with reference to the attached drawings, in which

[0024] FIG. 1 shows schematically, in a side view, a vehicle with a vehicle seat comprising an actuating assembly according to the disclosure,

[0025] FIG. 2 shows schematically, in a perspective front view from above, the vehicle seat with the actuating assembly and a beam structure according to the disclosure,

[0026] FIG. 3 shows schematically, in a perspective rear view from above, the vehicle seat with the actuating assembly and the beam structure according to the disclosure,

[0027] FIG. 4 shows schematically, in a perspective side view, the actuating assembly and the beam structure according to the disclosure,

[0028] FIG. 5 shows schematically, in a perspective rear view, the actuating assembly and the beam structure according to the disclosure,

[0029] FIGS. 6A-6B show schematically, in perspective rear views, a section of the vehicle seat with the actuating assembly and the beam structure, and a section of the vehicle seat without the actuating assembly and the beam structure, according to the disclosure, and

[0030] FIGS. 7A-7B show schematically, in a cross-sectional side view and in an enlarged cross-sectional side view, a section of the vehicle seat with the beam structure and a first actuator or a second actuator, and the beam structure and a part of the first actuator or the second actuator, according to the disclosure.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0031] Various aspects of the disclosure will hereinafter be described in conjunction with the appended drawings to illustrate and not to limit the disclosure, wherein like designations denote like elements, and variations of the described aspects are not restricted to the specifically shown embodiments, but are applicable on other variations of the disclosure.

[0032] FIG. 1 schematically shows a vehicle V with an adjustable vehicle seat 1 equipped with an actuating assembly 4. The vehicle seat 1 may be suitable for use in any type of vehicle V, such as for example cars as illustrated in the figure. In the figures, the frame structure and the actuating assembly are illustrated. It should however be understood that the vehicle seat may involve other non-illustrated components or structural parts, such as for example padded or upholstered seat components and seat cover fabrics or other cover structures.

[0033] The vehicle seat 1 has an extension in a longitudinal direction D.sub.LO corresponding to a longitudinal direction of the vehicle V in which the vehicle seat 1 is arranged. A lateral direction D.sub.LA is defined as a direction perpendicular to the longitudinal direction D.sub.LO corresponding to a lateral direction of the vehicle V. A vertical direction D.sub.V is defined as a direction perpendicular to the longitudinal direction D.sub.LO and the lateral direction D.sub.LA, corresponding to a vertical direction of the vehicle V. The expressions upper, lower, upwards, and downwards, used in this context are referring to directions in relation to the vehicle seat 1 in the vertical direction D.sub.V. The expressions front, rear, forwards, and rearwards used in this context are referring to directions in relation to the vehicle seat 1 in the longitudinal direction D.sub.LO. The directions are for example indicated in FIG. 2.

[0034] As illustrated in FIGS. 2 and 3, the vehicle seat 1 comprises a lower frame 2 and a movable upper frame 3. The upper frame 3 is pivotably arranged in relation to the lower frame 2. In the illustrated embodiment, the lower frame 2 comprises a front part 2a and a rear part 2b. The upper frame 3 comprises a front part 3a and a rear part 3b. The front part 3a of the upper frame 3 is pivotably arranged in relation to the front part 2a of the lower frame 2 around a front pivot axis A. The front pivot axis A is extending in the lateral direction D.sub.LA or essentially in the lateral direction D.sub.LA, allowing the upper frame 3 to be raised or lowered for adjusting a seating height and a seating angle ? of the vehicle seat 1. The upper frame 3 is movably connected to the lower frame 2 via the actuating assembly 4, and as understood from for example FIGS. 1 and 2, the rear part 3b of the upper frame 3 is movably connected to the rear part 2b of the lower frame 2 via the actuating assembly 4. With this arrangement, the rear part 3b of the upper frame 3 is height adjustable and configured for being raised or lowered. The upper frame 3 may, as illustrated in for example 2 be connected to a backrest structure, and the backrest structure may suitably be adjustably attached to the upper frame 3. The lower frame 2 is suitably connected to a rail structure or similar arrangement for longitudinal adjustment of the vehicle seat 1 relative to a floor structure of the vehicle V.

[0035] The actuating assembly 4 comprises a first actuator 4a and a second actuator 4b, as shown in FIGS. 2-6A. The first actuator 4a and the second actuator 4b are configured to cooperate with each other for displacing the upper frame 3 in relation to the lower frame 2. The first actuator 4a is arranged in connection to a first rear lateral side 12a of the lower frame 2, and the second actuator 4b is arranged in connection to a second rear lateral side 12b of the lower frame 2, as understood from the figures. The actuating assembly 4 further comprises a beam structure 5 connected to and extending between the first actuator 4a and the second actuator 4b. The beam structure 5 is extending in the lateral direction D.sub.LA, as understood from the figures. The beam structure 5 may be made of any suitable material providing high bending and torsional stiffness, such as for example polymeric materials, composite materials or metals. A high bending and torsional stiffness of the beam structure 5 is desired for minimizing movement between the actuators for an efficient adjustment of the vehicle seat 1 via the actuators.

[0036] In the illustrated embodiment, the first actuator 4a comprises a first drive unit 6a and a first displacement member 7a. The first displacement member 7a is arranged between the lower frame 2 and the upper frame 3 and is used for displacing the upper frame 3 relative to the lower frame 2 when driven by the first drive unit 6a. The first drive unit 6a is attached to the beam structure 5, and the first drive unit 6a is suitably attached to a first bracket 5a or similar arrangement of the beam structure 5. The first bracket 5a may be arranged as an integrated structural part of the beam structure 5, or alternatively as a separate part attached to the beam structure 5 as illustrated in for example FIG. 2.

[0037] In the illustrated embodiment, the second actuator 4b comprises a second drive unit 6b and a second displacement member 7b. The second displacement member 7b is arranged between the lower frame 2 and the upper frame 3 and is used for displacing the upper frame 3 relative to the lower frame 2 when driven by the second drive unit 6b. The second drive unit 6b is attached to the beam structure 5, and the second drive unit 6b is suitably attached to a second bracket 5b or similar arrangement of the beam structure 5. The second bracket 5b may be arranged as an integrated structural part of the beam structure 5, or alternatively as a separate part attached to the beam structure 5 as illustrated in for example FIG. 2.

[0038] The first actuator 4a and the second actuator 4b are floatingly connected to the lower frame 2 via the beam structure 5. With floatingly connected is meant that the respective actuators are free to move in relation to the lower frame 2 via the beam structure 5. The floating connection has been established through the arrangement of the beam structure 5 to the lower frame 2, where the beam structure 5 is allowed to move relative to the lower frame 2. The lower frame 2 comprises a cradle structure 2c that is extending in the lateral direction D.sub.LA of the vehicle seat 1, as understood from for example FIGS. 6A-6B. The beam structure 5 is slidingly arranged relative to the cradle structure 2c of the lower frame 2, and upon displacement of the upper frame 3 in relation to the lower frame 2 the beam structure 5 is allowed to slide relative to the cradle structure 2c. The cradle structure 2c has suitably a U-shape like or curved cross-sectional configuration with an upper surface 2c.sub.U, and a lower surface 2c.sub.L as shown in FIGS. 7A-7B. The beam structure 5 is arranged to slide on the upper surface 2c.sub.U upon displacement of the upper frame 3 relative to the lower frame 2.

[0039] In the illustrated embodiment, the beam structure 5 is provided with a first sliding surface 5.sub.S1 arranged in connection to the first actuator 4a, and a second sliding surface 5.sub.S2 arranged in connection to the second actuator 4b. The first sliding surface 5.sub.S1 and the second sliding surface 5.sub.S2 are arranged as downwards facing surfaces on lateral opposite sides of the beam structure 5. The first sliding surface 5.sub.S1 and the second sliding surface 5.sub.S2 are positioned in connection to the upper surface 2c.sub.U of the cradle structure 2c, as shown in for example FIGS. 7A-7B, and during displacement of the vehicle seat 1, the first sliding surface 5.sub.S1 and the second sliding surface 5.sub.S2 are configured to slide relative to the upper surface 2c.sub.U due to angular displacement of the displacement members as will be further described below. The first sliding surface 5.sub.S1 and the second sliding surface 5.sub.S2 suitably have shapes corresponding to the shape of the cradle structure 2c for an efficient sliding movement. The first sliding surface 5 and the second sliding surface 5.sub.S2, as well as the upper surface 2c.sub.U of the cradle structure 2c may be provided with or made of low friction material for an efficient sliding movement.

[0040] Through the attachment of the first drive unit 6a and the second drive unit 6b to the beam structure 5, also the first drive unit 6a and the second drive unit 6b are floatingly connected to the lower frame 2 via the beam structure 5. As shown in for example FIGS. 2, 3, 6A, and 7A-7B, the drive units are positioned below the cradle structure 2c for a compact solution of the actuating assembly 4. It should be understood that the first drive unit 6a and the second drive unit 6b are not attached to the lower frame 2, but instead to the beam structure 5 via the respective first bracket 5a and second bracket 5b. When the beam structure 5 is moving in relation to the lower frame 2 through the sliding movement between the first sliding surface 5.sub.S1 and the second sliding surface 5.sub.S2 relative to the upper surface 2c.sub.U of the cradle structure 2c, the first drive unit 6a and the second drive unit 6b are moving with the beam structure 5 relative to the lower frame 2. In this way, the first drive unit 6a and the second drive unit 6b are floatingly arranged relative to the lower frame 2 via the beam structure 5.

[0041] As described above, the first actuator 4a comprises the first displacement member 7a, and the first displacement member 7a is rotatably connected to the beam structure 5 via a first bearing 13a, as illustrated in FIGS. 7A-7B. The first bearing 13a may be of any suitable type and is allowing the first displacement member 7a to rotate relative to the beam structure 5. The first displacement member 7a has an elongated shape with an axial extension in a first axial direction A1, and the first displacement member 7a is arranged to rotate around an axis extending in the first axial direction A1. The first drive unit 6a is connected to the first displacement member 7a and configured for rotating the first displacement member 7a when displacing the upper frame 3 in relation to the lower frame. The first drive unit 6a is suitably arranged as an electric motor that is drivingly engaging a lower end 11a of the first displacement member 7a, where the lower end 11a of the first displacement member 7a is arranged below the cradle structure 2c. The first drive unit 6a may be connected to the lower end 11a via a gear unit or other suitable gearing mechanism. The first drive unit 6a may rotate the first displacement member 7a in opposite directions for raising or lowering the upper frame 3 relative to the lower frame 2, as indicated in FIG. 4.

[0042] As described above, the second actuator 4b comprises the second displacement member 7b, and the second displacement member 7b is rotatably connected to the beam structure 5 via a second bearing 13b, as illustrated in FIGS. 7A-7B. The second bearing 13b may be of any suitable type and is allowing the second displacement member 7b to rotate relative to the beam structure 5. The second displacement member 7b has an elongated shape with an axial extension in a second axial direction A2, and the second displacement member 7b is arranged to rotate around an axis extending in the second axial direction A2. The second drive unit 6b is connected to the second displacement member 7b and configured for rotating the second displacement member 7b when displacing the upper frame 3 in relation to the lower frame 2. The second drive unit 6b is suitably arranged as an electric motor that is drivingly engaging a lower end 11b of the second displacement member 7b, where the lower end 11b of the second displacement member 7b is arranged below the cradle structure 2c. The second drive unit 6b may be connected to the lower end 11b via a gear unit or other suitable gearing mechanism. The second drive unit 6b may rotate the second displacement member 7b in opposite directions for raising or lowering the upper frame 3 relative to the lower frame 2, as indicated in FIG. 4.

[0043] The first drive unit 6a and the second drive unit 6b are suitable arranged as synchronized electric motors, where the operation of the first drive unit 6a and the second drive unit 6b are synchronized. Thus, when there is a desire to raise or lower the upper frame 3 relative to the lower frame 2, the first drive unit 6a and the second drive unit 6b are operated simultaneously for a synchronized rotation of the respective displacement members. The drive units or the displacement members may be connected to sensors for measuring the displacement of the upper frame 3 or the rotational movement of the drive units in order to control that the operation is fully synchronized. The electric motors may be driven in opposite directions for raising or lowering the upper frame 3 relative to the lower frame 2 via the displacement members through rotation of the displacement members. When raising the upper frame 3 both the first drive unit 6a and the second drive unit 6b may drive the displacement members in a first rotational direction, and when lowering the upper frame 3 both the first drive unit 6a and the second drive unit 6b may drive the displacement members in a second rotational direction opposite the first rotational direction, as indicated in FIG. 4. In an alternative configuration of the actuating assembly, the first drive unit 6a may drive the first displacement member 7a in a first rotational direction and the second drive unit 6b the second displacement member 7b in a second rotational direction opposite the first rotational direction when raising the upper frame 3, and the first drive unit 6a may drive the first displacement member 7a in the second rotational direction and the second drive unit 6b the second displacement member 7b in the first rotational direction when lowering the upper frame 3. The rotational directions may depend on the configuration of the displacement members.

[0044] The operation of the first drive unit 6a and the second drive unit 6b may for example be initiated by a user of the vehicle V by actuating a seat adjustment switch, such as a switch knob or other suitable switch component for vehicle seat adjustment. It should be understood that the adjustment of the vehicle seat could be automated and controlled via a control unit, for example via a vehicle user profile with stored seat adjustment or positioning information.

[0045] The first displacement member 7a and the second displacement member 7b are extending through the cradle structure 2c. As shown in for example FIG. 6B, the cradle structure 2c is provided with a first passage 14a for receiving the first displacement member 7a and a second passage 14b for receiving the second displacement member 7b. The first passage 14a and the second passage 14b may be arranged as two openings in the cradle structure 2c with extensions allowing angular displacement of the respective first displacement member 7a and second displacement member 7b. The lower end 11a of the first displacement member 7a and the lower end 11b of the second displacement member 7b are arranged below the cradle structure 2c, as shown in FIGS. 7A-7B.

[0046] The beam structure 5 further comprises a first structural element 5c arranged in connection to the lower end 11a of the first displacement member 7a and a second structural element 5d arranged in connection to the lower end 11b of the second displacement member 7b. As shown in FIGS. 6A and 7A-7B, the first structural element 5c and the second structural element 5d are arranged below the cradle structure 2c and configured for preventing upward movements of the first displacement member 7a and the second displacement member 7b in a vehicle impact event. Thus, the first structural element 5c and the second structural element 5d are restricting an upwards movement of the beam structure 5, where the first displacement member 7a and the second displacement member 7b are connected to the beam structure 5 for a safe construction. The lower surface 2c.sub.L of the cradle structure 2c is preventing upwards movements of the first structural element 5c and the second structural element 5d if the displacement members are exerted to upwards directed forces in a vehicle impact event.

[0047] The first structural element 5c is suitably arranged in connection to the first bracket 5a, as shown in for example FIGS. 7A-7B, and the first structural element 5c is positioned between the cradle structure 2c and the first drive unit 6a. The lower end 11a of the first displacement member 7a is extending through the first structural element 5c. The lower end 11a of the first displacement member 7a may be provided with a threaded portion and secured with a first nut 16a arranged below the first structural element 5c. The first structural element 5c may be provided with a pre-tensioning mechanism with a first spring unit 17a, such as a set of plate springs for pre-tensioning the beam structure 5 towards the cradle structure 2c via the first displacement member 7a. The pre-tensioning is pushing the first displacement member 7a axially downwards for an assembly of the first actuator 4a without play for an efficient load distribution in a vehicle impact event.

[0048] The second structural element 5d is suitably arranged in connection to the second bracket 5b, as shown in for example FIGS. 7A-7B, and the second structural element 5d is positioned between the cradle structure 2c and the second drive unit 6b. The lower end 11b of the second displacement member 7b is extending through the second structural element 5d. The lower end 11b of the second displacement member 7b may be provided with a threaded portion and secured with a second nut 16b arranged below the second structural element 5d. The second structural element 5d may be provided with a pre-tensioning mechanism with a second spring unit 17b, such as a set of plate springs for pre-tensioning the beam structure 5 towards the cradle structure 2c via the second displacement member 7b. The pre-tensioning is pushing the second displacement member 7b axially downwards for an assembly of the second actuator 4b without play for an efficient load distribution in a vehicle impact event.

[0049] With a vehicle impact event is meant any situation where the vehicle V is exposed to impact forces, such as when the vehicle V is hitting an object or an object is hitting the vehicle V. Typical vehicle impact events are when the vehicle V is involved in a crash situation or collision, for example with another vehicle, or if the vehicle V leaves a roadway in a run-off-road collision or similar event. If the vehicle V is involved in a collision, impact forces will act on the vehicle seat 1.

[0050] In a rear-end collision, or in a collision where the rear end of the vehicle V runs into an object, the rear part 3b of the upper frame 3 is pushed in a direction downwards towards the rear part 2b of the lower frame 2, due to impacting forces in the longitudinal vehicle direction D.sub.LO in such a vehicle impact event acting on the vehicle seat 1 and causing a rotational movement of the vehicle seat 1. The displacement members and the connections of the displacement members to the respective seat frames are designed to withstand pushing forces in such a vehicle impact event, and the arrangement with the two actuators are providing a balanced load path.

[0051] In a head-on collision, or in a collision where the front end of the vehicle V runs into an object, the rear part 3b of the upper frame 3 is pulled in a direction upwards away from the rear part 2b of the lower frame 2, due to impacting forces in the longitudinal vehicle direction D.sub.LO in such a vehicle impact event acting on the vehicle seat 1 and causing a rotational movement of the vehicle seat 1. The displacement members and the connections of the displacement members to the respective seat frames are designed to withstand pulling forces in such a vehicle impact event, and the arrangement with the two actuators are providing a balanced load path.

[0052] As shown in FIGS. 2, 3 and 6A, the first displacement member 7a is connected to the upper frame 3 via a first pivoting member 8a and the second displacement member 7b is connected to the upper frame 3 via a second pivoting member 8b. The first pivoting member 8a and the second pivoting member 8b are pivotably connected to the upper frame 3. The first pivoting member 8a and the second pivoting member 8b are in the illustrated embodiment connected to a beam member 3c of the upper frame 3, where the beam member 3c is extending in a lateral direction D.sub.LA. The beam member 3c of the upper frame has a tube-like configuration and the first pivoting member 8a and the second pivoting member 8b are inserted into the beam member 3c. In the illustrated embodiment, the first pivoting member 8a and the second pivoting member 8b have plug-like configurations, and the first pivoting member 8a and the second pivoting member 8b are free to rotate in relation to the beam member 3c upon displacement of the upper frame 3 relative to the lower frame 2. It should however be understood that the first pivoting member 8a and the second pivoting member 8b may be connected to the upper frame 3 in other ways depending on the design and construction of the vehicle seat 1.

[0053] The first displacement member 7a is rotatably connected to the first pivoting member 8a and the second displacement member 7b is rotatably connected to the second pivoting member 8b. The first displacement member 7a and the second displacement member 7b are configured for displacing the upper frame 3 in relation to the lower frame 2 upon rotation of the first displacement member 7a and the second displacement member 7b respectively. The rotational movement of the first displacement member 7a is established by the first drive unit 6a, and the rotational movement of the second displacement member 7b is established by the second drive unit 6b, as described above and indicated in FIG. 4.

[0054] In the illustrated embodiment, the first displacement member 7a is arranged as a threaded screw with an extension in the first axial direction A1. The first displacement member 7a is further arranged with a first threaded section 9a. As shown in for example FIG. 6A, the first threaded section 9a is arranged with outer threads above the lower end 11a of the first displacement member 7a. The first pivoting member 8a comprises a first threaded opening 10a configured for engaging the first threaded section 9a of the first displacement member 7a. The first threaded opening 10a comprises inner threads that are matching the outer threads of the first threaded section 9a. The first threaded section 9a is thus in threaded engagement with the first threaded opening 10a for an efficient engagement between the first displacement member 7a and the first pivoting member 8a. Upon rotation of the first displacement member 7a, the first pivoting member 8a is displaced along the first displacement member 7a in the first axial direction A1, as indicated with the double arrow in FIG. 4. Depending on the rotational direction of the first displacement member 7a and through the threaded engagement, the first pivoting member 8a can be moved in a direction upwards or in a direction downwards along the first displacement member 7a.

[0055] In the illustrated embodiment, the second displacement member 7b is arranged as a threaded screw with an extension in the second axial direction A2. The second displacement member 7b is further arranged with a second threaded section 9b. As shown in for example FIG. 6A, the second threaded section 9b is arranged with outer threads above the lower end 11b of the second displacement member 7b. The second pivoting member 8b comprises a second threaded opening 10b configured for engaging the second threaded section 9b of the second displacement member 7b. The second threaded opening 10b comprises inner threads that are matching the outer threads of the second threaded section 9b. The second threaded section 9b is thus in threaded engagement with the second threaded opening 10b for an efficient engagement between the second displacement member 7b and the second pivoting member 8b. Upon rotation of the second displacement member 7b, the second pivoting member 8b is displaced along the second displacement member 7b in the second axial direction A2, as indicated with the double arrow in FIG. 4. Depending on the rotational direction of the second displacement member 7b and through the threaded engagement, the second pivoting member 8b can be moved in a direction upwards or in a direction downwards along the second displacement member 7b.

[0056] As indicated in FIGS. 6B and 7A, the beam member 3c is provided with through bores for receiving the first displacement member 7a and the second displacement member 7b respectively. A first set of openings 15a are arranged in the beam member 3c in connection to the first pivoting member 8a for receiving the first displacement member 7a when threaded into the first threaded opening 10a of the first pivoting member 8a. The first set of openings 15a are having greater extensions than the cross-section of the first displacement member 7a for allowing the pivoting movement of the first pivoting member 8a relative to the beam member 3c. A second set of openings 15b are arranged in the beam member 3c in connection to the second pivoting member 8b for receiving the second displacement member 7b when threaded into the second threaded opening 10b of the second pivoting member 8b. The second set of openings 15b are having greater extensions than the cross-section of the second displacement member 7b for allowing the pivoting movement of the second pivoting member 8b relative to the beam member 3c.

[0057] Through the connection of the first pivoting member 8a and the second pivoting member 8b to the upper frame 3, the rear part 3b of the upper frame 3 can be displaced in upwards and downwards movements relative to the rear part 2b of the lower frame 2 upon simultaneous rotational movements of the first displacement member 7a and the second displacement member 7b by the respective drive units, as indicated with the double arrow in FIG. 6A.

[0058] To operate the vehicle seat 1 for an adjustment of the upper frame 3 relative to the lower frame 2, a control unit is suitably distributing power to the actuating assembly 4. The control unit is for example receiving an actuating command from a switch device operated by a user of the vehicle, or alternatively the control unit is automatically operating the vehicle seat. Upon adjustment of the vehicle seat when the actuating assembly 4 is powered, the first actuator 4a and the second actuator 4b are operated, and the first actuator 4a and the second actuator 4b are cooperating for displacing the upper frame 3 in relation to the lower frame 2. When powered, the first drive unit 6a and the second drive unit 6b are simultaneously rotating the first displacement member 7a and the second displacement member 7b respectively. The coordinated simultaneous rotational movements of the displacement members are forcing the first pivoting member 8a and the second pivoting member 8b to move axially along the respective displacement members, as described above for a displacement of the upper frame 3 relative to the lower frame 2. Depending on the rotational direction of the drive units, the pivoting members are simultaneously moving in a direction upwards along the displacement members for raising the upper frame 3 of the vehicle seat 1, or alternatively the pivoting members are simultaneously moving in a direction downwards along the displacement members for lowering the upper frame 3 of the vehicle seat 1. When the upper frame 3 has reached a desired position, the power distribution to the drive units is suitably shut off. When raising the upper frame 3 the seating angle ? is increased, and when lowering the upper frame 3 a seating angle ? is decreased, as understood from FIGS. 6A-6B.

[0059] Through the floating arrangement of the actuators in connection to the lower frame 2, the pivoting arrangement of the upper frame 3 to the lower frame 2, and the pivoting connection of the displacement members in connection to the upper frame 3, the displacement members are exhibiting a small angular displacement for an efficient and tension free operation with optimized load paths, as indicated with the curved double arrow in FIG. 7A. The load paths are extending from the upper frame 3 directly to the lower frame 2 via the displacement members arranged at rear corners of the vehicle seat 1. The drive units are not forming part of the load paths through the floating arrangement and the direct connection of the lower frame 2 and the upper frame 3 via the displacement members, for a direct and efficient force distribution in a vehicle impact event.

[0060] It will be appreciated that the above description is merely exemplary in nature and is not intended to limit the present disclosure, its application or uses. While specific examples have been described in the specification and illustrated in the drawings, it will be understood by those of ordinary skill in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure as defined in the claims. Furthermore, modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from the essential scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular examples illustrated by the drawings and described in the specification as the best mode presently contemplated for carrying out the teachings of the present disclosure, but that the scope of the present disclosure will include any embodiments falling within the foregoing description and the appended claims. Reference signs mentioned in the claims should not be seen as limiting the extent of the matter protected by the claims, and their sole function is to make claims easier to understand.

REFERENCE SIGNS

[0061] 1: Vehicle seat [0062] 2: Lower frame [0063] 2a: Front part, Lower frame [0064] 2b: Rear part, Lower frame [0065] 2c: Cradle structure [0066] 2c.sub.U: Upper surface [0067] 2c.sub.L: Lower surface [0068] 3: Upper frame [0069] 3a: Front part, Upper frame [0070] 3b: Rear part, Upper frame [0071] 3c: Beam member [0072] 4: Actuating assembly [0073] 4a: First actuator [0074] 4b: Second actuator [0075] 5: Beam structure [0076] 5.sub.S1: First sliding surface [0077] 5.sub.S2: Second sliding surface [0078] 5a: First bracket [0079] 5b: Second bracket [0080] 5c: First structural element [0081] 5d: Second structural element [0082] 6a: First drive unit [0083] 6b: Second drive unit [0084] 7a: First displacement member [0085] 7b: Second displacement member [0086] 8a: First pivoting member [0087] 8b: Second pivoting member [0088] 9a: First threaded section [0089] 9b: Second threaded section [0090] 10a: First threaded opening [0091] 10b: Second threaded opening [0092] 11a: Lower end, First displacement member [0093] 11b: Lower end, Second displacement member [0094] 12a: First rear lateral side [0095] 12b: Second rear lateral side [0096] 13a: First bearing [0097] 13b: Second bearing [0098] 14a: First passage [0099] 14b: Second passage [0100] 15a: First set of openings [0101] 15b: Second set of openings [0102] 16a: First nut [0103] 16b: Second nut [0104] 17a: First spring unit [0105] 17b: Second spring unit [0106] ?: Seating angle [0107] A: Front pivot axis [0108] A1: First axial direction [0109] A2: Second axial direction [0110] D.sub.LA: Lateral direction [0111] D.sub.LO: Longitudinal direction [0112] D.sub.V: Vertical direction [0113] V: Vehicle