Lordosis Support

Abstract

The invention relates to a lumbar support for a seat backrest, having a lumbar support basket 12 arranged in a frame 10 of a seat backrest, a pulling device which changes the position of the lumbar support basket 12 relative to the frame, characterised in that the pulling device has two pull cables 16, 17 which are coupled to the lumbar support basket 12 and the frame in such a way that when tension is exerted on the pulling device the lumbar support basket 12 is moved relative to the plane defined by the frame 10 of the seat backrest.

Description

The present invention relates to a lumbar support for a seat backrest. The invention relates in particular to a lumbar support fitted in backrests of motor vehicle seats, office furniture seats, or domestic furniture seats.

Lumbar supports are fitted in seat backrests in order to provide sufficient support in the lumbar-vertebra or lordosis region of a person seating on the seat by forming a corresponding supporting surface. For this, the lumbar support customarily has a lumbar support basket which is fastened to a frame arranged in the seat backrest. Furthermore, a pulling device by which the position of the lumbar support basket can be changed relative to the frame is customarily provided.

In the prior art, a lumbar support basket is known which is fastened on one side to the support frame, while the other side is fastened via a Bowden cable to the other frame side, the position of the support basket relative to the plane defined by the frame being changed when tension is exerted on the Bowden cable. The unilateral tensile load results in an asymmetrical action of the tensile load, so that the lumbar support basket is also moved laterally when tension is exerted on the Bowden cable, and not just perpendicularly to the plane defined by the frame. Furthermore, the movement does not take place symmetrically to the axis which is perpendicular to the plane defined by the frame, so that the person sitting on the seat feels unsymmetrical relief of the strain on the lordosis region when tension is exerted on the Bowden cable. Furthermore, a relatively long pull length is necessary for a relatively small movement of the lumbar support basket.

An object of the present invention is to provide a lumbar support which enables a symmetrical movement of the lumbar support basket while achieving a greatest possible adjustment of the lumbar support basket for a small pulling movement.

This object is achieved according to the invention by the independent claim. Preferred embodiments of the invention are described in the dependent claims.

According to the invention, the lumbar support for a seat backrest has a lumbar support basket arranged in a frame of a seat backrest. Furthermore, a pulling device which changes the position of the lumbar support basket relative to the frame is provided. The pulling device has two pull cables which are coupled to the lumbar support basket and the frame in such a way that when tension is exerted on the pulling device the lumbar support basket is moved relative to the plane defined by the frame of the seat backrest. Symmetrical tension on the lumbar support basket is achieved by means of the two pull cables of the pulling device, so that a symmetrical movement of the lumbar support basket with respect to an axis which is perpendicular to the plane defined by the frame of the seat backrest is achieved. At the same time, by means of the two pull cables, for the same pull length twice the adjusting travel is achieved compared with the prior art, in which the lumbar support basket is equipped with only one pull cable.

Preferably, the lumbar support basket has a guiding device in which the pulling device is movably guided. According to a preferred embodiment, the two pull cables are movably located in the guiding device. Preferably, the pulling device is a Bowden cable, the actuator for actuating the Bowden cable being attached to the frame.

According to a further preferred embodiment, both pull cables are fastened at their one end to the frame. In this embodiment, the respective other ends of the pull cables are fastened to the actuator. The pull cables can, in one embodiment, run together from the actuator up to the guiding device, the pull cables branching at the guiding device and each pull cable running from the branching up to the frame, where it is fastened.

Furthermore, preferably the pull cables run upon the branching at the guiding device in opposite directions and are fastened to opposite sides of the frame. These two lateral parts of the pull cables from the branching up to the frame are responsible for the position of the lumbar support basket relative to the frame.

When tension is exerted on the pull cables, the region of the pull cables from the fastening to the frame up to the guiding device can be shortened, whereby the lumbar support basket is displaced relative to the plane defined by the frame. In this case, the region in which the two pull cables run jointly up to the guiding device lengthens. The region of one pull cable from the guiding device to the lateral frame is shortened, this region likewise for the other pull cable from the guiding device to the other frame side likewise being shortened, whereby the adjusting travel of the lumbar support basket is doubled for a given pull length.

According to another embodiment, the two pull cables are arranged in such a way that the second pull cable runs from the actuator up to the guiding device. The first pull cable runs from one frame side via the guiding device to the other frame side and is coupled to the second pull cable in such a way that when tension is exerted on the second pull cable the effective cable length of the first pull cable between the two frame sides is shortened. In this case, when tension is exerted on the second pull cable a subregion of the first pull cable is moved in the direction of the second pull cable perpendicularly to the course of the first pull cable, so that the effective cable length of the first pull cable from the first frame side to the second frame side shortens.

The invention is explained in more detail below using an exemplary embodiment with reference to the accompanying schematic drawings, in which:

FIG. 1 shows a front view of the lumbar support arranged in the frame of a seat backrest,

FIG. 2 shows a rear view of the lumbar support in the frame,

FIG. 3 shows a plan view of the lumbar support in an unloaded position,

FIG. 4 shows a plan view of the lumbar support in a loaded position,

FIG. 5 shows an enlarged view of the lumbar support in a front view,

FIG. 6 shows an enlarged rear view of the lumbar support,

FIG. 7 shows a detail view of the guiding device in the unloaded position of the Bowden cable, and

FIG. 8 shows a detail view of the guiding device in the loaded position of the Bowden cable.

FIG. 1 shows a front view of a frame 10 which is part of a seat backrest (not illustrated) of a motor vehicle seat. Furthermore, in the lower region of the seat frame a lumbar support 11 having a lumbar support basket 12 is provided. The lumbar support basket is actuated via a Bowden cable, an actuator 13 fastened to one side of the frame 10 being provided in order to actuate the Bowden cable. In the embodiment illustrated in FIG. 1, two different positions of the actuator 13 are illustrated, the actuator 13a and the actuator 13b. The two actuators 13a and 13b show only different possible arrangements of a single actuator in the backrest frame, there being no provision for two actuators. Provided above the lumbar support basket 12 is a wire mat 14 which can be connected to the frame 10, for example, via springs (not illustrated). The wire mat 14 can also be connected to the lumbar support basket 12. A connection between lumbar support basket 12 and wire mat 14 is not absolutely necessary, however.

As can also be seen in FIG. 2 inter alia, two pull cables 16 and 17 of the Bowden cable are guided in a cable sleeve 15. Starting from the actuator 13, these two pull cables run jointly in the cable sleeve 15 up to a guiding device 18, at which they branch, one pull cable 16 being fastened to one side 10a of the frame 10, and the pull cable 17 branching off at the guiding device, running to the other side of the frame 10 and being fastened there. As can be seen in FIGS. 5 and 6 inter alia, the lumbar support basket is designed in the form of a plate and is slightly concavely curved in order to guide the lower lumbar region. The lumbar support basket has a middle section 20, to which the guiding device 18 is attached. Furthermore, two lateral sections 21 and 22 are provided. Braces 23 are provided on the side of the lumbar support basket facing away from the back of the person leaning against the seat backrest.

As can be seen in FIGS. 2 and 6, the cable sleeve 15 is attached to the guiding device 18. The guiding device 18 has two arcuate guiding sections 24 and 25 which effect the diversion of the two pull cables 16 and 17. The two pull cables 16 and 17 are movably arranged in the guiding device and are diverted by about 90° substantially in opposite directions at the diversions 24 and 25 and guided in guiding eyes 26 on the lumbar support basket before being fastened to the frame 10 by fixing elements 27.

In FIGS. 3 and 4, the different positions of the lumbar support basket relative to the frame are depicted. In the position illustrated in FIG. 3, no tension is exerted on the pull cables 16 and 17 and the lumbar support basket is in a rest position where it is pushed by upholstery (not illustrated) of the seat into the position illustrated in FIG. 3. In this position of FIG. 3, the two cables run together, as illustrated in FIG. 7, up to a joining nipple 28 which joins the two pull cables 16 and 17, before they are guided by the diversions to the sides of the frame. If the actuator 13 is now actuated, tension is exerted on the two pull cables 16 and 17, which moves the joining nipple and the jointly running region of the pull cables, as illustrated in FIG. 8, in the direction of the cable sleeve 15. As a result, the region of the pull cables 16 and 17 which previously ran horizontally, diverted by the diversions 24 and 25, is in each case shortened by the height h. Overall, the region of the pull cables which runs horizontally between the two sides 10a and 10b of the frame 10 is shortened by the height 2h. Overall, the effective horizontal pull cable length thus shortens by the height 2h. This horizontal pull cable length is responsible for the position of the lumbar support basket 12 relative to the plane defined by the frame. As a result, the lumbar support basket is, as illustrated in FIG. 4, pushed in the direction of the back (not illustrated).

From the foregoing description, the following advantage is thus obtained for a person skilled in the art by means of the invention.

Firstly, the lumbar support basket is moved symmetrically perpendicularly to the plane defined by the frame. Furthermore, an adjustment of the lumbar support basket by the length 2h is achieved by a pull length h at the actuator. The actuator for actuating the pull cable can be actuated either manually or by an electric motor.

Instead of the two pull cables 16 and 17 illustrated in the figures, it is also possible to provide a first pull cable running from one side 10a of the frame to the other side 10b, while providing a second pull cable running from the actuator up to the joining nipple 28. The first pull cable is in this case joined to the second pull cable at the joining nipple 28. When tension is exerted on the second pull cable, which is fastened to the actuator, this pull cable lifts the other pull cable in the direction of the cable sleeve 15, so that once again the lumbar support basket is moved into the position illustrated in FIG. 4, since the length of the pull cable stretching between the two sides of the frame is shortened by the length 2h.

LIST OF REFERENCE SYMBOLS

• 10 Frame
• 10 a Side
• 10 b Side
• 11 Lumbar support
• 12 Lumbar support basket
• 13 Actuator
• 14 Wire mat
• 15 Cable sleeve
• 16, 17 Pull cables
• 18 Guiding device
• 20 Middle section
• 21, 22 Lateral sections
• 23 Brace
• 24, 25 Diversion
• 26 Guiding eyes
• 27 Fixing elements
• 28 Joining nipple

Claims

1-8. (canceled)

9. Lumbar support for a seat backrest, having a lumbar support basket arranged in a frame of a seat backrest,a pulling device with a Bowden cable, the actuator of the Bowden cable being attached to the frame, wherein the pulling device changes the position of the lumbar support basket relative to the frame and has two pull cables which are coupled to the lumbar support basket and the frame in such a way that when tension is exerted on the pulling device the lumbar support basket is moved relative to the plane defined by the frame of the seat backrest,

10. Lumbar support for a seat backrest, having a lumbar support basket arranged in a frame of a seat backrest,a pulling device which changes the position of the lumbar support basket relative to the frame and which has two pull cables which are coupled to the lumbar support basket and the frame in such a way that when tension is exerted on the pulling device the lumbar support basket is moved relative to the plane defined by the frame of the seat backrest, wherein the pulling device is a Bowden cable, the actuator of the Bowden cable being attached to the frame,

11. Lumbar support according to claim 10, wherein both pull cables are fastened by one of their ends to the frame.

12. Lumbar support according to claim 10, the pull cables upon the branching being diverted in opposite directions and fastened to opposite sides of the frame.

13. Lumbar support according to claim 10, wherein when tension is exerted on the pulling device the regions of the pull cable from the fastening to the frame up to the guiding device are shortened, whereby the lumbar support basket is displaced relative to the plane defined by the frame.