Vehicle seat with a vertically movable support surface

The present invention relates to a vehicle seat whose back has a supporting part in form of a flexible closed loop adapted to move approximately vertically by a circulatory motion by rotating around two horizontal axes and adapted to be driven by friction the back of the vehicle occupant. ₁

It has been found that the seat backs of vehicles used to date exert compression repeated efforts on the spine of the driver and passengers due to the reaction to the frictional force of the back of the person sitting when moving vertical that person due to inequality and bumps in the road and to the elasticity of the seat petition. The friction forces and reactions can be relatively high, since the file is generally used in an inclined position with a relatively high back pressure on the folder. To remedy this defect, it has been proposed to include in the record a pneumatic cushion capable of deforming along the oscillating movement of the back (DE-A-24.20.277). In the same document it was proposed to replace the air bag by endless belts mounted on two sets of tapered roller freely rotating on two parallel axes. The assembly is recessed into the backrest and occupies only part of the height of the bearing surface of the back. His back resting against the tapered rollers, it was proposed to coat the foam rollers, but such a coating makes it difficult to rotation of the rollers and virtually nullified the effect ribbons. On the other hand, below and above the moving ribbons, the back bears against fixed parts so that the friction forces and reactions are concentrated in these points, the desired beneficial effect being thus eliminated. The position of the device also is not suitable for all sizes of drivers and passengers. Finally, driven by clothing ribbons, either up or down tend to be pinched between the ribbons on the rollers, and the fixed part of the record.

In another document (FR-A-2403910), it was proposed to make a seat hanging folder, in which the padded part of the backrest can slide vertically on a fixed support being held in its middle position by springs compensators, one pulling down and the other is pulling up. Traction, respectively compression compensation springs when the backrest is raised, have the effect of exercise in turn a force downward, which can also be exercised while the back of the seated person has not downward movement correspondant.- the movement of the seated person and the oscillating movement of the backrest can be occasionally even against phase so that not only the effect of suppressing the reaction to friction can be largely negated but that the compression of the spring is added to the negative effect of compression found in a conventional seat.

A similar chair is described in WO-A-85/00 029. This chair, though with a filling is in the form of an endless belt stretched around a swing support consists of a cushion and passing over two rollers mounted for free rotation, substantially behaves the same way as the previous seat because the friction between the pad and the pad is such that the insert is driven by the cushion in its oscillating movement.

The present invention aims to achieve a comfortable seat on every occasion in which the mobile support surface of the backrest is capable of providing a beneficial effect on the spine in all conditions, regardless of the size of the person sitting and without the disadvantages of previously proposed systems.

The vehicle seat according to the invention is characterized in that said support portion forms a continuous surface extending throughout the height of the backrest and is supported directly and resiliently between said shafts by rotary members so as to circulate around the case.

According to one embodiment, by allowing the circulatory movement of the loop in one direction, namely up to its front part in contact with the back of the passenger, it is also possible to obtain an effect additional favorable: when the passenger goes down relative to the folder, the mobile part of it is retained and response back from friction forces on the file generates a force acting upwards, that is to say, a force traction to the spine. But such tension is beneficial by its effect comparable to a back extension.

The accompanying drawing shows, by way of example, two embodiments of the seat according to the invention.<ul><li>Figure 1 is a perspective view of a seat according to a first embodiment.</li><li>Figure 2 is a perspective view identical to that shown in Figure 1 but with a portion broken away of the folder.</li><li>Figure 3 is a perspective view of a portion of the same seat.</li><li>Figure 4 is a schematic view of a folder of the locking mechanism.</li><li>Figure 5 is a cut-away and partially exploded view of the seat according to a second embodiment.</li><li>Figure 6 is a side view of a lateral strip of the second embodiment.</li><li>Figure 7 is a detailed view of a roller supporting the ribbon.</li><li>Figure 8 is a sectional view of the control valve of the hydraulic circuit, in a first position.</li><li>Figures 9, 10 and 11 respectively show the same valve in three other positions.</li><li>12 shows a variant of the second embodiment.</li></ul>

The seat as shown in Figure 1 is virtually indistinguishable externally of a conventional seat. It comprises a petition 1 comprising a cushion spring and with padding and a backrest 2 having a central portion 3 for supporting the back of each side of which are arranged two side uprights 4 and 5 fixed and back, connected at their upper end by part 6 in the form of arch topped by a headrest 7. the present case usual means for adjusting the inclination of 8. Since this spring, however, the figures 2, 3 and 4, part 3 of the record consists by a tape 9 in flexible but resistant material, preferably inelastic, for example a synthetic material semi-hard, on which is fixed a synthetic foam 10 coated with a cloth or any other seat upholstery. The tape 9 and the foam 10 form a closed loop in the manner of a drive belt of which it is also possible to draw for the choice of the material constituting the band 9. The loop thus formed is mounted on two rollers 11 and 12, rotatably mounted to the lower part and the upper backrest respectively, pivoted on the axes in the lateral uprights 4 and 5 of the file on a rigid support 13 (Figure 4). These two rollers 11 and 12 are further connected by a transmission chain which ensures an identical rotation of the rollers so as to maintain a constant tension on the tape 9 and to discharge it from this task. Between the rollers 11 and 12, the movable part 3 is supported by rollers 14 rotatably and freely mounted at the end of oscillating arms 15 hinged to the support 13 and whose axes are further mounted on springs 16 based on the support 13, so as to further increase the comfort of the file. The tape 9 is extended laterally on each side of the foam pad 10 (Figure 3) and this projecting part is provided with notches 17 in the manner of a toothed belt, these notches cooperating with notches 18 and 19 of cylinders 11 and 12. the projecting parts of the tape 9 are hidden in the side uprights 4 and 5. the cylinder 11 is mounted completely free to rotate. The cylinder 12 is also free to rotate, but its rotation can be locked by the driver in the counterclockwise direction or in both directions by means of a locking device described in connection with Figure 5. The unidirectional rotation , that is to say in the direction corresponding to movement of the back in the direction of the arrow F (Figure 2) can be secured by any known means.

According to Figure 4 the roller 12 is rotatably mounted on a shaft 25 fixed in rotation but movable axially. This shaft 25 is supported, in amounts 4 and 5, by two guides 26 and 27 which prevent it from turning. At one of its ends the shaft 25 is provided with a disc 28 secured to the shaft and provided with teeth or protrusions 29, 30 directed towards the roller 12. On the other side of the roller 12, between the roller and the guide 27, the shaft 25 carries a freewheeling device, the outer ring 31 is keyed on the shaft 25 and therefore fixed in rotation while the inner wheel 32 is free to rotate in the direction corresponding to the arrow F (fig. 2). This wheel 32 is provided with a toothing for engagement with a toothing corresponding edge 33 provided at the end of the roller 12. The end of the shaft 25 and screwed in a control knob 34. The positioning the shaft 25 is ensured by a spring 35 mounted between the guide 27 and the belt 31.

In the position shown the roller 12 is free to rotate in both directions: the backrest 3 follows the back of the passenger in its upward and downward movements.

If you turn the knob 34 clockwise, the shaft 25 is pulled towards the button and the teeth 29, 30 of the disk 28 are blocking the roller 12.

If you turn the knob 34 in the counterclockwise direction (unscrewing) the shaft 25 is pushed to the left by the spring 35 and the wheel 32 meshes with the teeth 33 of the roll. When the passenger moves upward relative to the file, under the effect of relaxing the springs of petition 1, back drives Part 3 of the dossier by adherence. It then moves freely with the back of the passenger circulating around the rollers 11 and 12. When the passenger goes down relatively the record, part 3 is retained by the upper roller 12 blocked in reverse rotation. back of the friction on the portion 3a then has the effect of generating a reaction resulting in a traction on the back, that is to say on the spine.

If there is concern that the degree of freedom given to the file allows the passenger during strong shaking, to be thrown against the roof of the vehicle, it is possible to limit the upward movement of Part 3 of the file by limiting the speed of rotation of the roller 11 and therefore the roller 12 by the drive chain by means of a Watt integral regulator of the transmission chain. The controller is effective in both directions of rotation, which has the effect of limiting the accelerations in both directions. Such a regulator being adjustable as regards its braking effect on the roll 11, it allows an adaptation to the weight of the driver. Furthermore this regulator is a safety for vertical shock device, for example when the vehicle passes through a pothole.

The seat according to the second embodiment shown in Figure 5, comprises a padded petition 41 and a folder 42 having a padded portion 43. for example of synthetic foam, forming a closed loop, through which elastic bands 44 attached to each of their ends to a flexible strip 45 made ​​of steel, each of these strips being supported by toothed rollers 46, 47 and 48 and by a series of toothed wheels 49, this mobile being mounted themselves on a frame 50 U-shaped up the back support and also bearing a headrest 51. the bands 45 are hidden in a side panel 52. the angle of the backrest can be adjusted in a known manner by means of a button 53. the steel strips 45 are provided with cuts 54 in which the movable teeth 46 to engage toothed 49. in the frame 50, the height of the roller 47 is also mounted a hydraulic pump 55 (Figure 6) mounted in a hydraulic circuit 56 comprising in series, a first valve 57 whose shutter is actuated by a button 58 accessible on the side of the back, above the button 53, and a second valve 59. the pump 55 is driven by the roller 47, himself even driven by the tape 45 with the padded part of the record. If necessary, multiplication is provided between the axis of the roller 47 and the pump 55. The other movable supporting ribbons 45 are freely mounted on their respective axes. When the folder is driven, the pump 55 is then actuated and the fluid is circulated in the circuit 56, provided that the valves 57 and 59 are open. The valve 59 is provided for limiting the flow rate of the circuit, that is to say limit the pump rotation speed of 55, that is to say limit the acceleration of the folder so as to prevent the passenger, during strong shaking, being thrown against the vehicle roof. This valve 59 is in principle not adjustable by the user, but is set at the factory or workshop, based on the weight of the passenger. The valve 57, actuated by the passenger, is shown in section in different positions in Figures 8 to 11. This valve comprises a valve body 60 having an inlet 61 and an outlet 62 aligned, and a cylindrical shutter rotary 63, actuated by the button 58, and having two mutually perpendicular passages 64 and 65. one of the orifices 66 of the passage 65 is formed as a non-return valve by means of a ball 67 or a cone valve or any other known construction.

In the position shown in Figure 8, the fluid can flow in the direction of the arrow F, but not in opposite direction, due to the non-return valve 26. This flow direction of the fluid corresponds to the rise of the part previous record of 43, which means that the passenger may be lifted without friction on the record with respect to petition 41, but down again by rubbing the folder.

In the position shown in Figure 9, which is reached by rotating the shutter 63 of 45 ° relative to the position shown in Figure 8, the valve 57 is fully closed. The fluid can not flow; the pump is blocked, and with it the folder 43. The seat behaves like a conventional seat.

By continuing to turn the shutter 63 clockwise, you arrive in the braking control range of the file (Figure 10). The valve is gradually opened so that the fluid passage is gradually released.

Once that has been rotated 90 °, it reaches the position shown in Figure 11 in which the valve 57 completely open and allows fluid flow in both directions, that is to say a freedom of the file 43 both upwards and downwards.

The steel bands 45, which are loaded in tension towards the inside of the seat by the elastic strips 4 are retained laterally by example as shown in Figure 7. The rollers 46, 47 and 48 have a frustoconical portion 68 on which builds a part 45a of the strip 45 formed such that it forms an angle with the rest of the ribbon. This tape 45 is not extensible, it is retained by the part 68. It is seen in this drawing teeth 69 which accompany the rollers 46, 47 and 48.

It is possible to provide other means for laterally retaining steel tapes 45. It is for example possible to provide linear bearings in the areas between the rollers 46 and 47 and between the rollers 47 and 48 on the other. It is possible to provide the outside edge of the tape 45 small rolling tapered rollers and retained laterally in a track integral part of the 50.

In the variant shown in Figure 12, the strips 45 are supported, in the lumbar region, by two gears 70 whose diameter is such that they support the ribbon 45 on two diametrically opposite parts of their circumference. The common axis of these wheels 70 is further mounted in slots 71 oriented substantially perpendicular to the strips 45, slots in which the wheel axle 70 can be moved and locked in the desired position by means of a clamping device, for example a nut integral with a handle. The lights 71 are carried in holders 72 fixed to the frame 10. The axis of the wheels 70 could be mounted in the slots via sliders mounted on parallel screw the lights to their positioning along the lights. The pump 55 is driven either by one of the mobile 70, either by one of the other mobile driven by the ribbons 45.

The ability to change the position of the axis of the wheels 70 provides the user the ability to adapt as best as possible the curvature of the case to the particular curvature of the lumbar area.

The seat of the invention has an additional advantage: the circulation of the file has the effect of renewing the part contacting the back of the passenger, thereby reducing the heating of the back and sweat.