Longitudinal adjuster and carrier seat
By designing a fastened connection between the movable spindle retainer and the lower rail in the longitudinal adjuster, the problem of deformation of the spindle under overload is solved, ensuring the normal adjustment function of the seat, especially in emergency situations.
Patent Information
- Application Number
- CN202380072830.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-10-14
- Filing Date
- 2023-02-03
- Publication Date
- 2025-05-27
AI Technical Summary
The existing longitudinal adjuster can easily cause the spindle to deform under overload, which will affect the seat adjustment function, especially in case of emergency, which cannot be adjusted normally.
A longitudinal adjuster is designed in which the spindle retainer is movably mounted on the track and is connected to the lower track by a fastening element to ensure that the spindle does not undergo undesired twisting or buckling at high longitudinal loads.
It effectively avoids deformation of the spindle under high longitudinal load conditions, ensures that the seat can still be adjusted normally in an emergency, and meets the need for emergency evacuation from behind the vehicle seat.
Smart Images
Figure CN120051397A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a longitudinal adjuster, in particular for a vehicle seat. Furthermore, the present invention also relates to a vehicle seat. Background Art
[0002] Longitudinal adjusters are known in the prior art, in particular for vehicle seats. The longitudinal adjuster typically has at least one pair of tracks, which is formed by a first track and a second track that is longitudinally movable relative to the first track; and at least one drive device, which is formed at least by a motor and a spindle or a drivable spindle nut with a trapezoidal thread. The tracks engage with each other to form an internal channel. A spindle holder connected to the second track is arranged in the internal channel and connected to the spindle.
[0003] In response to a force application, in particular a force application in the forward direction, such as in the event of a collision or incorrect use, the spindle may deform, such that the seat cannot be adjusted in an emergency. Summary of the Invention
[0004] The present invention is based on the following object: to improve a longitudinal adjuster of the initially described type, in particular to reduce or avoid permanent deformation of the spindle after overload; and to provide a corresponding vehicle seat.
[0005] Technical solution
[0006] According to the present invention, the first object is achieved by a longitudinal adjuster having the features of claim 1. According to the present invention, the second object is achieved by a vehicle seat having the features of claim 10.
[0007] Advantageous embodiments that can be used individually or in combination with each other are the subject matter of the dependent claims.
[0008] A longitudinal adjuster according to the present invention, in particular for a vehicle seat, includes at least one pair of tracks, which is formed by a first track and a second track that are configured to be displaceable relative to each other along a longitudinal direction; and a drive device, which is formed at least by a motor and a spindle nut that is drivable by the motor and is arranged to be longitudinally movable on a spindle that is particularly stationary, wherein the tracks engage with each other to form an internal channel, and wherein at least one spindle holder is arranged in the internal channel and is connected to one of the tracks on one side and to the spindle on the other side. According to the present invention, the at least one spindle holder is movably mounted on the track.
[0009] The first track is preferably a seat track, in particular a top track, which can be connected to a vehicle seat. The second track is preferably a floor track, in particular a lower track, which can be connected to the vehicle structure. At least one spindle retainer is preferably movably mounted on the second track.
[0010] In response to the application of a predetermined force, for example during an accident, the force can be conducted via the first track, the spindle nut, the spindle and the spindle retainer away from the vehicle seat to the second track.
[0011] The present invention is based on the following consideration: Even after an accident, especially when a high longitudinal load acts on the longitudinal adjuster, the vehicle seat must still allow adjustment of the movable track (= the first track) and thus adjustment of the vehicle seat, for example, for an emergency evacuation from the seat row located behind the vehicle seat. To ensure this, the longitudinal adjuster is designed such that the spindle does not twist or buckle at least in the front region viewed in the longitudinal direction between the spindle retainer and the gear mechanism of the spindle nut and / or the motor.
[0012] The present invention is also based on the following consideration: In the case of a high track longitudinal load, such as a forward load, a tensile force acts on the spindle in the rear spindle region between the gear mechanism of the spindle nut / motor and the rear spindle retainer in the fixed track (= the second track, also referred to as the lower track), while a compressive force acts on the spindle in the front spindle region between the gear mechanism of the spindle nut / motor and the front spindle retainer. If a specific force is exceeded, elastic and plastic elongation can occur in the rear region of the spindle and elastic or permanent lateral displacement of the spindle can occur in the front region of the spindle, which results in undesired bending and / or buckling of the spindle. Therefore, the spindle nut (also referred to as the output gear) actively connected to the spindle can no longer rotate within the gear mechanism in the region of undesired bending and / or buckling, such that the longitudinal adjustment is blocked or locked.
[0013] Due to the fact that at least one of the spindle retainers, in particular the front spindle retainer viewed in the longitudinal direction, is movably mounted on the second track, in particular the fixed track or the lower track, the undesired deformation of the spindle in the front region, such as twisting and / or buckling, is at least reduced or even does not occur at all and is thus prevented. In other words, the present invention allows avoidance of spindle deformation in the case of a high longitudinal load.
[0014] Specifically, the spindle retainer is linearly movably, for example longitudinally movably, mounted on the track, in particular the second track. The longitudinally movable mounting of the spindle retainer particularly means the linear movement of the spindle retainer in the longitudinal direction of the track, along the longitudinal axis or the track axis.
[0015] To fix the spindle retainer to the second track, at least two fastening elements can be provided, for example. For example, the second track can have at least two fastening receivers, and the at least two fastening elements are movably mounted in the fastening receivers. Specifically, the fastening receivers are configured such that the fastening elements are mounted with limited linear mobility.
[0016] For example, the fastening receivers are designed to prevent linear movement of the fastening elements in one direction. In the opposite direction, the fastening elements are designed to allow limited linear movement of the fastening elements.
[0017] The corresponding fastening receivers can include, for example, a stop or a block, wherein, when a force is applied, the linear movement of the fastening element is blocked by the stop or the block. In addition, the corresponding fastening receivers can be designed such that, in the case of mechanical stress on the second track, the fastening elements can linearly move and be longitudinally movable from the normal position in the direction towards the compensation position, in particular in the direction of the acting force, for example forward in the longitudinal direction.
[0018] For example, the corresponding fastening receivers can be configured as notches in the second track. Such an embodiment of the corresponding fastening receivers as notches allows for linear longitudinal mobility of the fastening elements in the fastening receivers while allowing fixing of the lateral position of the fastening elements in the fastening receivers. In addition, at least two fastening receivers can be oriented in the same way in the longitudinal direction.
[0019] The corresponding spindle retainer, in particular the front spindle retainer and / or the rear spindle retainer, can be connected to the second track, in particular the lower track, by means of the fastening elements. The lower track can be fastened to the vehicle floor or the vehicle body. The second track is fixedly connected to the vehicle floor or the vehicle body in the vertical direction. The fastening elements are configured as rivets, for example.
[0020] The spindle can be connected to the second track via the spindle retainer. The spindle is configured as a fixed spindle. Optionally, an attachment plate can be provided between the spindle retainer and the second track. Specifically, the optional attachment plate can be provided on the front spindle retainer viewed in the longitudinal direction between the front spindle retainer and the second track. The attachment plate can be configured in a U-shape as an additional mounting piece. The spindle retainer is then connected to the attachment plate at the bottom of the U-shape. For example, the spindle is connected to the attachment plate via the spindle retainer by material bonding, such as a welded connection. However, the attachment plate can also be omitted and the spindle retainer can be directly fixed to the bottom of the second track.
[0021] The corresponding spindle retainer can be riveted to the second track such that, when a force exceeding a predetermined force occurs in the longitudinal direction, limited linear movement of the spindle retainer relative to the second track is allowed.
[0022] To still allow longitudinal mobility after the riveting process, a spring element can be provided. For example, a spring element with a predetermined pre-tension can be provided between the spindle retainer and the second track. The spring element can be formed, for example, as a disc spring. Here, the fastening element, the fastening receiver, the attachment plate, and the spring element are constructed and arranged relative to each other such that the spring element is provided with a predetermined pre-tension and does not get stuck between the fastening head (= rivet head) and the underside of the second track. This can prevent the spindle retainer from wobbling during travel.
[0023] By means of the spring element, a predetermined frictional force can be generated between the spindle retainer and the second track, such that in normal operation, during longitudinal adjustment, the spindle retainer is firmly fixed to and positioned on the second track, and can only move longitudinally relative to the second track in the event of an accident or misuse and if a predetermined frictional force is exceeded.
[0024] The fastening receiver configured as a groove allows the spindle retainer and, optionally, the attachment plate together with the fastening element to move longitudinally forward relative to the second track. The fastening element in the fastening receiver strikes, in particular, a stop or a block in the longitudinal direction backward. Thereby, the tensile force can be absorbed without displacing the attachment plate and / or the spindle retainer. In other words, the tensile force is directly transmitted into the second track (= lower track) through the stop or the block in the fastening receiver. Since the spindle retainer and the fastening element can be offset forward in the longitudinal direction in the fastening receiver configured as a groove, a compressive force cannot be transmitted initially.
[0025] In other words, the groove and the fastening element, for example, a rivet, are positioned relative to each other in the longitudinal direction or the x-direction in each case such that displacement is not possible in one direction (here backward) in the event of overload, but displacement is possible in the opposite direction (here forward) in the event of high forces.
[0026] The spindle is fixed. A spindle nut is mounted on the spindle for rotational and longitudinal movement, and the spindle nut can be driven by a motor.
[0027] The external thread of the spindle can be structured in the form of a trapezoidal thread. The internal thread of the spindle nut can be structured in the form of a trapezoidal thread. The external thread of the spindle and the internal thread of the spindle nut can each be structured as a double thread.
[0028] The longitudinal adjuster can preferably include two spindle retainers, in particular a front spindle retainer and a rear spindle retainer. The spindle nut is mounted longitudinally movably on the spindle between the front spindle retainer and the rear spindle retainer.
[0029] According to the invention, this object is also achieved by a vehicle seat having a longitudinal adjuster according to the invention, in particular according to the longitudinal adjuster described above. Description of the Drawings
[0030] The present invention will be described in more detail in connection with the advantageous exemplary embodiments shown in the drawings. However, the present invention is not limited to these exemplary embodiments. In the drawings:
[0031] Figure 1 : shows a schematic view of a vehicle seat having a longitudinal adjuster,
[0032] Figure 2 : shows along Figure 1 a cross-sectional view of the longitudinal adjuster according to the invention along the median line II-II, and
[0033] Figure 3 : shows an enlarged cross-sectional view of the spindle holder of the longitudinal adjuster according to the invention in the region III of Figure 2 . Detailed Description of the Invention
[0034] Corresponding components in all the figures have the same reference numerals.
[0035] As Figure 1 schematically shown, the prior art vehicle seat 100 will be described hereinafter with reference to three spatial directions extending perpendicular to each other. When the vehicle seat 100 is mounted on a vehicle, the longitudinal direction x extends generally horizontally and preferably parallel to the vehicle longitudinal direction, which corresponds to the normal driving direction of the vehicle. The transverse direction y extending perpendicular to the longitudinal direction x is also horizontally oriented in the vehicle and extends parallel to the vehicle transverse direction. The vertical direction z extends perpendicular to the longitudinal direction x and the transverse direction y. When the vehicle seat 100 is mounted in a vehicle, the vertical direction z preferably extends parallel to the vehicle vertical axis.
[0036] The position data and / or orientation data used, such as front, rear, top and bottom, are related to the viewing direction of an occupant sitting in the vehicle seat 100 in a normal seating position, wherein the vehicle seat 100 is mounted in the vehicle in a use position suitable for transporting people, has an upright backrest 104, and is oriented in the conventional manner along the driving direction. However, the vehicle seat 100 can also be assembled or moved in a different orientation, for example, transversely to the driving direction. Unless otherwise specified, the vehicle seat 100 is constructed to be mirror-symmetrical with respect to a plane perpendicular to the transverse direction y.
[0037] The backrest 104 can be pivotally provided on the seating part 102 of the vehicle seat 100. To this end, the vehicle seat 100 can optionally include a control fitting 106, in particular an adjustment control fitting, a rotation control fitting, a latch control fitting or a fingerwheel control fitting.
[0038] The position data and / or orientation data used, such as radial, axial, and circumferential, are related to the rotational axis 108 of the control fitting 106. Radial means perpendicular to the rotational axis 108. Axial means in the direction of the rotational axis 108 or parallel to the rotational axis 108.
[0039] The vehicle seat 100 includes a longitudinal adjuster 110 (also referred to as a longitudinal adjustment device). The longitudinal adjuster 110 includes, for example, a track device 112 having a first track 114 and a second track 116. The first track 114 is adjustable relative to the second track 116 in the longitudinal direction x. The first track 114 is fastened to the seating part 102. The second track 116 is fastened to a structural element of the vehicle, such as the vehicle floor.
[0040] For greater clarity, in the following description, the first track 114 is referred to as the top track 114. This top track 114 (also referred to as a running track or slide rail) is assigned to the vehicle seat 100 and is designed to carry the vehicle seat 100. The second track 116 is referred to as the lower track 116 hereinafter. The lower track 116 is fixed and is connected, for example, to the vehicle floor.
[0041] Figure 2 A sectional view in the x-z plane of the longitudinal adjuster 110 according to the present invention along Figure 1 the line II-II is shown, and the longitudinal adjuster includes a track device 112 and a drive device 120.
[0042] The track device 112 of the vehicle seat 100 may include two track pairs 118 arranged parallel to each other. Each track pair 118 includes a fixed lower track 116 and a top track 114 that is longitudinally movable on the lower track.
[0043] Figure 2 An exemplary track pair in the track pair 118 is shown.
[0044] The longitudinal adjuster 110 includes a track device 112 having two track pairs 118 and a drive device 120, which is at least formed by a motor 122 and a spindle nut 124 that can be driven by the motor 122. A gear mechanism 126 may be provided between the motor 122 and the spindle nut 124. The vehicle seat 100 is fixedly connected to the longitudinal adjuster 110 by at least one seat retainer 128.
[0045] The spindle nut 124 is longitudinally movably arranged on the spindle 130. The spindle 130 is fixed. The spindle nut 124 is mounted on the spindle 130 to be rotatably and longitudinally movable, and the spindle nut can be driven by the motor 122 via the gear mechanism 126.
[0046] The lower track 116 and the upper track 114 can be joined to each other to form an internal passage 132. A spindle mount connected to the lower track 116 is disposed in the internal passage 132. The spindle mount may include one or more spindle holders 134. The spindle mount includes a front spindle holder 134.1 and a rear spindle holder 134.2. A spindle nut 124 is longitudinally movably mounted on the spindle 130 between the front spindle holder 134.1 and the rear spindle holder 134.2.
[0047] According to the invention, at least one spindle holder 134 is movably mounted on the lower track 116 (= fixed track, second track).
[0048] In particular, the front spindle holder 134.1 can be mounted on the lower track 116 to be linearly movable, for example longitudinally movable.
[0049] In order to fasten the spindle holder 134, in particular the linearly movable spindle holder, to the lower track 116, for example two fastening elements 138, in particular rivets, can be provided. The lower track 116 can for example have at least two fastening receivers 136, each for one spindle holder 134. The at least two fastening elements 138 are movably mounted in the fastening receivers 136.
[0050] The corresponding spindle holder 134 is connected to the fixed lower track 116 by the fastening element 138. The fastening element 138 is for example formed as a rivet.
[0051] In response to the application of a predetermined force, for example during an accident, the force can be conducted away from the vehicle seat 100 through the upper track 114, the spindle nut 124, the spindle 130 and the corresponding spindle holder 134 into the lower track 116, as will be described in detail below with reference to Figure 3 as will be illustrated by way of example.
[0052] Figure 3 Shows Figure 2 an enlarged cross-sectional view of the front spindle holder 134.1 of the longitudinal adjuster 110 according to the invention in region III of
[0053] The fastening receivers 136 in the lower track 116 are configured such that the fastening elements 138 are mounted to be linearly movable forward, in particular longitudinally movable, to a limited extent according to arrow 140.
[0054] For example, the corresponding fastening receiver 136 is designed to prevent linear movement of the associated fastening element 138 in one direction. To this end, the corresponding fastening element 138, in particular a rivet, abuts against the stop 136.1. In addition, the corresponding fastening receiver 136 is designed to allow limited linear movement of the associated fastening element 138 in the opposite direction according to arrow 140. To this end, the corresponding fastening receiver 136 is, for example, configured as a slot 136.2 in the lower track 116. In other words, the corresponding fastening receiver 136 is dimensioned larger than the external dimension of the associated fastening element 138 in the longitudinal direction x.
[0055] This embodiment of the corresponding fastening receiver 136 as a slot 136.2 allows linear longitudinal mobility while fixing the lateral position of the associated fastening element 138 within the fastening receiver 136.
[0056] The two fastening receivers 136 of the front spindle holder 134.1 are oriented in the longitudinal direction x in the same manner. The two fastening receivers 136 are arranged spaced apart from each other.
[0057] The spindle 130 can be connected to the lower track 116 via the front spindle holder 134.1 or alternatively, as shown in the example, via an attachment plate 142. The attachment plate 142 includes a passage opening 142.1 for the fastening element 138. The passage opening 142.1 corresponds to the external dimension of the fastening element 138.
[0058] For example, the spindle 130 is connected to the front spindle holder 134.1 by a material bond, for example by welding.
[0059] The front spindle holder 134.1 is riveted to the lower track 116 such that when a force exceeding a predetermined value occurs in the longitudinal direction x, according to arrow 140, the front spindle holder 134.1 is allowed to perform a linear movement relative to the lower track 116.
[0060] In order to still allow this longitudinal mobility after the riveting process, a spring element 144 is provided, for example. For example, the spring element 144 can be provided between the front spindle holder 134.1 and the lower track 116 with a predetermined pre-tensioning force. The spring element 144 can, for example, be formed as a disc spring.
[0061] The fastening element 138, in particular a rivet, is fixedly connected, in particular riveted, to the respective spindle holder 134.
[0062] The fastening element 138, the fastening receiver 136, the optional attachment plate 142, and the spring element 144 are in particular constructed and arranged relative to one another such that the spring element 144 is set with a predetermined pre-tensioning force and does not jam between the fastening head 138.1 (= rivet head) and the underside 116.1 of the lower track 116. The step height of the fastening head 138.1 together with the height of the spring element 144, such as a disc spring, defines the pre-tensioning force in the vertical direction z. Furthermore, the fastening element 138, the fastening receiver 136, the optional attachment plate 142, and the spring element 144 are designed such that jamming of the spring element 144, in particular a disc spring, is avoided. Thus, the longitudinal mobility of the spindle retainer 134 can be further achieved and is not restricted or impeded. Thereby, wobbling of the front spindle retainer 134.1 during travel can also be avoided.
[0063] By means of the spring element 144, a predetermined frictional force can be generated between the front spindle retainer 134.1 and the lower track 116 such that, during normal operation and during longitudinal adjustment, the front spindle retainer 134.1 is firmly fixed and stably positioned on the lower track 116. In the event of an accident or misuse in which a greater force is generated in the longitudinal direction x, and when the predetermined frictional force in the longitudinal direction x relative to the lower track 116 is exceeded, the spring element 144 allows the front spindle retainer 134.1 to move longitudinally by a limited amount through its fastening element 138 located in the fastening receiver 136, in particular forward in the direction of arrow 140.
[0064] The fastening receiver 136, which is configured as a groove 136.2, thus allows the front spindle retainer 134.1 and the optional attachment plate 142 together with the fastening element 138 to move forward by a limited amount longitudinally in the longitudinal direction x relative to the fixed lower track 116. Towards the rear in the longitudinal direction x, the fastening element 138 in the fastening receiver 136 strikes the respective stop 136.1 or abutment.
[0065] In other words, the tensile force is directly transmitted into the lower track 116 through the stop 136.1 in the fastening receiver 136. Since the front spindle retainer 134.1 and the fastening element 138 can be offset forward in the longitudinal direction x in the fastening receiver 136 configured as a groove 136.2, compressive forces cannot initially be transmitted. The groove 136.2 and the fastening element 138, such as a rivet, are each positioned relative to one another in the longitudinal direction x such that in one direction (here towards the rear, opposite to arrow 140), no displacement occurs during overload, but in the opposite direction (here forward, according to arrow 140), displacement can occur during high forces.
[0066] The external thread 130.1 of the main shaft 130 can be configured as a trapezoidal thread. The internal thread of the main shaft nut 124 (not shown in detail) can be configured as a trapezoidal thread. The external thread 130.1 of the main shaft 130 and the internal thread of the main shaft nut 124 can each be configured as a double thread.
[0067] The features disclosed in the above description, claims and drawings may be important for the implementation of the present invention in its various embodiments, either individually or in combination.
[0068] Although the present invention has been described in detail in the drawings and the foregoing description, these descriptions are for illustrative and exemplary purposes only and should not be construed as restrictive. In particular, the selection of the proportions of the various elements shown in the figures should not be construed as necessary or restrictive. In addition, the present invention is not particularly limited to the proposed exemplary embodiments. Those skilled in the art can make further modifications to the present invention and its implementation according to the foregoing disclosure, drawings and claims.
[0069] In the claims, the use of terms such as "comprising", "having", "including", "containing", etc. does not exclude other elements or steps. The use of an indefinite article does not exclude a plurality. A single device can perform the functions of multiple units or devices recited in the claims.
[0070] List of reference signs
[0071] 100 Vehicle seat
[0072] 102 Seating part
[0073] 104 Backrest
[0074] 106 Control fitting
[0075] 108 Axis of rotation
[0076] 110 Longitudinal adjuster
[0077] 112 Track device
[0078] 114 First track (top track)
[0079] 116 Second track (lower track)
[0080] 116.1 Bottom side
[0081] 118 Track pair
[0082] 120 Driving device
[0083] 122 Motor
[0084] 124 Spindle nut
[0085] 126 Gear mechanism
[0086] 128 Seat retainer
[0087] 130 Spindle
[0088] 130.1 External thread
[0089] 132 Internal passage
[0090] 134 Spindle retainer
[0091] 134.1 Front spindle retainer
[0092] 134.2 Rear spindle retainer
[0093] 136 Fastening receiver
[0094] 136.1 Stopper
[0095] 136.2 Groove
[0096] 138 Fastening element
[0097] 138.1 Fastening head
[0098] 140 Arrow
[0099] 142 Attachment plate
[0100] 142.1 Passage opening
[0101] 144 Spring element
[0102] x Longitudinal direction
[0103] y Transverse direction
[0104] z Vertical direction
Claims
1. A longitudinal adjuster (110), especially for a vehicle seat (100), wherein, the longitudinal adjuster (110) at least comprises: - a pair of tracks (118), which is formed by a first track (114) and a second track (116), and the first track and the second track are configured to be displaceable relative to each other along a longitudinal direction (x), and - a drive device (120), which is at least formed by a motor (122) and a spindle nut (124), and the spindle nut can be driven by the motor (122) and is arranged to be longitudinally movable on the spindle (130), wherein, the tracks (114, 116) engage with each other around to form an internal channel (132), wherein, at least one spindle holder (134) is arranged in the internal channel (132), and is connected to one of the tracks (116) on one side and to the spindle (130) on the other side, and wherein, the at least one spindle holder (134) is movably mounted on the track (116).
2. The longitudinal adjuster (110) according to claim 1, wherein, the at least one spindle holder (134) is linearly movably mounted on the track (116).
3. The longitudinal adjuster (110) according to claim 1 or 2, wherein, in order to fasten the at least one spindle holder (134) to the track (116), at least two fastening elements (138) are provided, and the track (116) has at least two fastening receivers (136), and the at least two fastening elements (138) are movably mounted in the at least two fastening receivers (136).
4. The longitudinal adjuster (110) according to claim 3, wherein, the fastening receivers (136) are configured such that the fastening elements (138) are mounted to be capable of limited linear movement.
5. The longitudinal adjuster (110) according to claim 3 or 4, wherein, the corresponding fastening receivers (136) are designed to prevent the linear movement of the fastening elements (138) in one direction and allow the limited linear movement of the fastening elements (138) in the direction opposite to the one direction.
6. The longitudinal adjuster (110) according to any one of claims 3 to 5, wherein, the corresponding fastening receivers (136) are configured as slots (136.2).
7. The longitudinal adjuster (110) according to any one of claims 3 to 6, wherein, the at least two fastening receivers (136) are oriented in the same way in the longitudinal direction (x).
8. The longitudinal adjuster (110) according to any one of the foregoing claims, wherein, the spindle (130) is connected to an attachment plate (142) via the spindle holder (134).
9. The longitudinal adjuster (110) according to any one of the foregoing claims, wherein, a spring element (144) having a predetermined pre-tightening force is provided between the spindle holder (134) and the second track (116).
10. A vehicle seat (100) having a longitudinal adjuster (110), the longitudinal adjuster being the longitudinal adjuster according to any one of the preceding claims.