Vehicle seat

A vehicle seat (1) having a squab (2) and the backrest (3) may be provided with a child squab or booster cushion (4). Various elements are provided on the seat which may move in response to the child squab (4) being provided. A first element that may move is a guide (10) which guides part of a seat belt (7). The guide (10) moves inwardly towards the central axis (8) of the seat. Other moveable restraints may be lateral restraints (62,63) which move forwardly from the backrest of the seat to be located to either side of the torso of a child occupying the child squab (4) and head restraints (64,65) which may move forwardly from the head rest.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a 371 National Stage of International application No. PCT/SE2006/000553, filed May 12, 2006 and published in English as WO 2006/123981 A1 on Nov. 23, 2006. This application claims the benefit of GB 0510368,4, filed May 20, 2005. The disclosures of the above applications are incorporated herein by reference.

The present invention relates to a vehicle seat, and more particularly relates to a vehicle seat which may be adapted to seat a child.

Conventional safety belt arrangements which are often installed in motor vehicles are usually in the form of a three-point belt arrangement.

A three-point belt arrangement is usually formed by a single continuous belt which is fixed at one end by an anchorage to part a vehicle which is on one side of a vehicle seat, at a position which is below the level of the squab of the seat.

The belt has a first section which extends upwardly from the anchorage on said one side of the seat, over the lap of a seat occupant to a tongue which is inserted and locked into a buckle on the other side of the seat.

The three-point belt has a second section which extends diagonally upwardly from the tongue, across the torso of the seat occupant to a guide loop. The guide loop is fixed to the wall or door pillar of the motor vehicle at a position which is on the opposite side of the seat occupant to the buckle, with the guide loop being positioned above the level of the shoulder of the seat occupant.

The belt arrangement has a third section which extends downwardly from the guide loop to a retractor which is mounted to the vehicle on the same side as the guide loop, but at a position below the guide loop.

Safety requirements in modern vehicles usually require the belt fixing, buckle, guide loop and retractor to be positioned at specified distances from one another to ensure that when the safety belt is being worn by a seat occupant the first section of the belt extends over the lap of the occupant in the correct position, and more particularly the second section of the safety belt extends over the correct part of the torso and the centre of one shoulder of the occupant. The required positioning of the points of the safety belt when the safety belt is being worn are chosen such that the safety belt provides optimum protection for an average sized occupant in the event that a crash situation occurs. Such an average sized occupant is typically of average adult size, or the size and weight of a 50 percentile male dummy.

Therefore, when an average sized adult is wearing a conventional safety belt, the lap and torso parts of the safety belt extend over the occupant at the correct positions, making the safety belt both comfortable to wear, and ensuring that the safety belt offers the optimum protection to the seat occupant should a crash situation occur.

If a smaller than average sized occupant, such as a child, is seated in a vehicle and wearing a conventional safety belt of the type discussed above, the sections of the safety belt do not usually pass over the smaller occupant at the correct positions. This is most noticeably the case when a small child is seated on the vehicle seat, where the child's shoulders are at a much lower level than the shoulders of an adult seated on the same seat. In this case the second section of the safety belt extends at a high level across the child, and in some cases only extends across the very upper part of the child's torso and across the child's neck. This incorrect positioning of the second section of the safety belt on a child can potentially be very dangerous, as the second section may exert a large force on the neck of the child during a crash situation, which may injure the neck of the child.

Therefore, in an attempt to alleviate this problem the seat may be provided with a child squab, or booster cushion, which is placed above the level of the squab of the seat, to allow the child to be seated on top of the child squab at a higher level than the upper level of the squab of the seat. The child squab thus acts to raise the level of the shoulders of the child when the child is seated, so that the second section of the safety belt passes diagonally at a lower level across the torso of the child, away from the neck of the child.

Although the use of a child squab, or booster cushion, can alleviate the problem of the second section of the safety belt passing over the neck of the child, the use of such a child squab can create a different problem. This different problem results from the child squab raising the seated child so that the second section of the safety belt passes across the torso of the child at an angle which results in the second section of the safety belt extending below and to one side of the shoulders of the child. In this case, the second section of the safety belt does not pass over a shoulder of the child, and thus the safety belt is not able to restrain the child correctly. In a crash situation the child may be thrown forwardly by the forces of the crash, and as the safety belt does not pass over a shoulder of the child, the child may not be sufficiently restrained from moving upwardly and the child may be thrown “over” the second section of the safety belt and strike part of the vehicle, possibly causing injury.

A further problem with the use of a child squab or booster cushion is that the squab or booster cushion does not, of itself, provide any lateral support for a child utilising the child squab or booster cushion and in particular does not provide any lateral support for the torso of the child and does not provide any lateral support for the head of the child.

The present invention seeks to provide an improved vehicle seat.

According to this invention there is provided a vehicle seat incorporating a squab and a backrest, the seat comprising at least one restraint element which is moveably mounted relative to the backrest, the restraint element being moveable between a first position and a second position, there being a drive arrangement connected to the or each restraint element to move the element from the first position to the second position in response to the seat being provided with a child squab to accommodate a child.

In one embodiment the child squab is formed integrally with the vehicle seat, the child squab being moveable from a retracted position, in which the seat is adapted to seat an adult, to an operative position to provide said child squab in a position to accommodation a child.

Preferably the said drive arrangement moves the or each restraint element in response to movement of the child squab between said retracted position and said operative position.

In an alternative embodiment the drive arrangement is responsive to a separate child squab being provided on said seat as a booster cushion to accommodate a child.

Conveniently the seat incorporates a sensor which senses the presence of the child squab on the squab of the seat, the sensor being configured to actuate the drive arrangement.

Preferably the or each restraint element is moveable by a wire linkage system incorporating at least one Bowden cable which forms at least part of the drive arrangement.

Alternatively the or each restraint element is moveable by a drive arrangement which incorporates one or more electrically actuable elements.

Conveniently the electrically actuable elements comprise electric motors.

Preferably the or a said restraint element comprises a safety belt guide element, the safety belt guide element being moveably mounted to the backrest of the seat, to one side of the central longitudinal axis of an upper part of the backrest of the seat to guide a safety over a shoulder of an occupant of the seat, with the guide element being moveable from said first position to a second position which is closer to the central longitudinal axis of the back rest than the first position.

Conveniently the or a restraint element comprises a restraint element moveable from said first position in which the restraint element is accommodated within the backrest of the seat, to a second position in which the restraint projects from the backrest of the seat, the said restraint element being positioned to one side of the child squab.

Advantageously there are two said restraint elements accommodated within the backrest of the seat positioned on respective sides of the child squab.

Preferably the or a restraint comprises a head restraint moveably mounted to the headrest of the seat and moveable from a first position, in which the restraint is retracted, to a second position in which the restraint extends forwardly of a central part of the headrest of the seat.

Conveniently two said head restraints are provided, there being a respective one on each side of the headrest.

Advantageously the or each restraint element is associated with a first locking arrangement having a first locking member for locking the restraint element in the first position and a second locking arrangement having a second locking member for locking the restraint element in the second position.

Referring initially toFIG. 1of the accompanying drawings, a vehicle seat1, in accordance with a preferred embodiment of the invention, has a squab2and a backrest3. The seat1incorporates an integrated moveable child supporting squab4which, when the seat1is to seat an adult, is retracted and forms the upper front part of the squab2, as shown inFIG. 1.

Vehicle seats which incorporate an integrated moveable child supporting squab are known in the art. An example of a vehicle seat which incorporates an integrated moveable child supporting squab is disclosed in British Patent Publication No. GB 2368272 A.

A three-point safety belt5is installed in the vehicle for use by an occupant of the vehicle seat1. The three-point safety belt5is shown inFIG. 1in an operative, buckled, condition but without an occupant being seated on the seat1.

The three-point safety belt5is a conventional safety belt of the type discussed above. The three-point safety belt5is attached at one end by an anchorage6to part of the vehicle on one side of the squab2and a lap section7extends (when the safety belt5is in use) to a tongue8which is locked into a buckle9on the other side of the squab2. A torso section9of the safety belt5extends diagonally upwardly from the tongue8, and through a moveable guide10which is moveably mounted to an upper part of the backrest3on one side of the central longitudinal axis A of the backrest3. The torso section9then extends diagonally upwardly from the moveable guide10to a guide loop11which is fixed to the wall of the vehicle. A third section12of the safety belt5extends down from the guide loop11to a retractor13which is mounted to the wall or floor of the vehicle below the guide loop11.

It should be noted that when the vehicle seat1is configured to seat an adult, with the moveable child supporting squab4retracted into the squab2of the seat1, the moveable guide10is in a first position, away from the central longitudinal axis A of the backrest3, as shown inFIG. 1. An adult can thus seat on the squab2of the seat1with the moveable guide10guiding the torso section9of the safety belt5over the central part of one of the shoulders of the adult, making the safety belt5comfortable to wear and offering optimised protection for the adult.

It is to be understood that the moveable guide10forms a lateral restraint element, restraining the part of the safety belt it is instantaneously contained within the guide, preventing lateral movement of that part of the belt, and thus causing the belt to follow a precisely predetermined course.

Referring now toFIG. 2, the seat1has been adapted to seat a child by moving the child supporting squab4to an operative position, above the rear part of the squab2of the seat1. It should be noted that upon movement of the child supporting squab4from the retracted position to the operative position, the moveable guide10has moved laterally from the first position to a second position, with the second position being closer to the central longitudinal axis A of the backrest3than the first position.

When the moveable guide10is in the second position, the moveable guide10guides the torso section9of the safety belt5over the central part of one of the shoulders of the child seated on the child supporting squab4. A child can thus sit on the child supporting squab4with the safety belt5being guided over the correct part of the torso of the child, making the safety belt5comfortable to wear for the child, whilst offering optimised protection for the child.

After the child supporting squab4has been moved to the operative position, the lap section7of the safety belt5is hooked beneath a hook member14which is mounted to one side of the child supporting squab4. The hook member14acts as a guide for the lap section7of the safety belt5to guide the lap section7over the lap of a child seated on the child supporting squab4, to a position which is close to one side of the child. The hook member14thus ensures that the lap section7of the safety belt5is pulled tight over the lap of the child, to offer optimised protection for the child.

Referring now toFIGS. 3 to 6of the accompanying drawings, the moveable guide10forms part of a guide arrangement15. The upper part of the moveable guide10is defined by a belt guide member16which has a generally rectangular planar base17with two upstanding walls18and19that extend upwardly from each end of the planar base17. Two flanges20and21are provided, each flange extending inwardly from the upper end of a respective upstanding wall18,19, part way across the length of the planar base17. A gap is formed between the ends of the flanges20,21, so that the belt guide member16of substantially C-shaped cross-section.

An upstanding section of an inverted T-sectioned support member22is attached to the underside of the planar plate17, to support the belt guide member16. The support member22has a generally rectangular enlarged lower end plate23, and the rectangular area defined by the enlarged lower end plate23is substantially the same as the rectangular area defined by the belt guide member16.

Two locking recesses24and25are formed in the lower side of the enlarged lower end plate23. The purpose of the locking recesses24,25will become clear from the following description.

The moveable guide10is dimensioned to be inserted into one end of an elongate hollow, open ended C-shaped housing26. The C-shaped housing26has an elongate planar base27with upstanding walls28and29that extend upwardly from the edge of the planar base27along the length of the C-shaped housing26. Elongate flanges30and31extend inwardly from the upper ends of the upstanding walls28and29, part way across the width of the elongate base27, with a guide slot32being defined between the ends of the elongate flanges30,31. The guide slot32extends along the entire length of the C-shaped housing26. The guide slot32has enlarged sections33and34at positions along the C-shaped housing26which correspond to the first and second positions of the moveable guide10.

During assembly of the guide arrangement15, the enlarged lower end23of the moveable guide10is inserted into one end of the C-shaped housing26, with the upstanding section of the T-shaped support member22extending through the guide slot32. The moveable guide10is thus held by the C-shaped housing26, with the T-shaped support member22being constrained to move linearly along the guide slot32. The enlarged lower end23of the moveable guide10prevents the T-shaped support member22from being pulled upwardly, and out from the C-shaped housing26. The moveable guide10is biased towards the first position by a guide biasing spring35.

Two pairs of spaced apart lock apertures36,37and38,39are formed along the central longitudinal axis of the planar base27of the C-shaped housing26, with each of the lock apertures36-39being positioned beneath the guide slot32. The purpose of the lock apertures36-39will become clear from the following description.

Two generally box shaped lock housings40and41each have an open end which is mounted to the underside of the planar plate27of the C-shaped housing26. Each of the open ends of the lock housings40and41extends around a respective pair of lock apertures36,37and38,39. Each of the lock housings40and41has a respective generally rectangular base42,43, and a relatively small diameter aperture44,45is formed in a central region of each rectangular planar base42,43. The purpose of each small diameter aperture44,45will become clear from the description below.

The lock housings40and41are substantially identical to one another, and each of the lock housings40,41houses a locking arrangement46,47which is substantially identical to a locking arrangement46,47within the other lock housing40,41.

Each of the locking arrangements46,47incorporates a substantially U-shaped locking member48,49, and each of the locking members48,49incorporates an elongate support bar50,51which is positioned inside a respective lock housing40,41. Each of the elongate support bars50,51has an upturned locking pin52-55formed integrally at each end of the bar.

The first pair of the lock apertures36,37corresponds to the first pair of locking pins52,53, and the first pair of locking pins52,53extends up from the interior of the first lock housing40through the first pair of lock apertures36,37and into the interior of the C-shaped housing26. The second pair of the lock apertures38,39corresponds to the second pair of locking pins54,55and the second pair of locking pins54,55extend up from the second lock housing41through the second pair of lock apertures38,39and into the interior of the C-shaped housing26. Each of the U-shaped locking members48,49is biased upwardly from the interior of their respective lock housing40,41towards the C-shaped housing26by a respective pair of biasing springs56,57and58,59.

The guide arrangement incorporates three Bowden cables60,61and62. A first Bowden cable60has an outer sheath63and an inner wire64. The inner wire64of the first Bowden cable60extends into the first lock housing40and is attached to the lower side of the U-shaped locking member48with the sheath63of the cable60engaging the housing40. A second Bowden cable61has an outer sheath65and an inner wire66, and the inner wire66extends through the second lock housing41and is attached to the lower side of the second U-shaped locking member49with the sheath65of the cable61engaging the housing41. A third Bowden cable62has an outer sheath67and an inner wire68. The outer sheath67is fixed relative to the C-shaped housing26, and the inner wire68is connected to the moveable guide10.

The third Bowden cable62forms part of a drive arrangement which is connected to the moveable guide10to move the guide element from the first position to the second position.

Referring now toFIG. 7, the Bowden cables60,61and62are connected to a control mechanism (not shown), and the control mechanism provides a connection between the Bowden cables60,61and62and a single control Bowden cable69. The control Bowden cable69has an outer sheath70and an inner wire71. The outer sheath70is mounted to a support flange72, and the inner wire71passes through an aperture73formed in the support flange72and an aperture74in an arm75of a pivoted lever76. The end of the inner wire71is fastened to the arm75by a locking nut or nipple77.

The pivoted lever76comprises a planar plate78, from which the arm75extends upwardly. The planar plate78is of generally rectangular shape, but with one end of the planar plate78being cut away so that the planar plate78presents a vertical edge79and an inclined edge80. The planar plate78is pivotally mounted to part of the vehicle by a pivot member81at a point close to the upper end of the planar plate78, below the arm75. The pivoted lever76is mounted such that if a force is exerted on the lower end of the vertical edge79, as indicated by arrow82, the pivoted lever76will pivot about the pivot member81in an anticlockwise direction. The pivoted lever76is biased in a clockwise direction by a coil spring83, such that the force applied in the direction of arrow82must be in excess of a predetermined level, dependent upon the coil spring83, in order to pivot the pivoted lever76. As the pivoted lever76pivots, the arm75is moved away from the support flange72, pulling the inner wire71through the support flange72and out from the outer sheath70of the control Bowden cable69.

When the vehicle seat1is to accommodate an adult, the child supporting squab4is retracted into the front part of the squab2, as shown inFIG. 1. However, if the vehicle seat1is to accommodate a child the child supporting squab4is moved to the operative position by actuating a movement mechanism (not shown). When the movement mechanism is actuated, the lever76is engaged and moved to pull the wire71of the control Bowden cable69. In response to this the control mechanism pulls the first inner wire64of the first Bowden cable60, causing the first U-shaped locking member48to be moved downwardly, against the bias of the springs56,57. As the U-shaped locking member48is moved downwardly, the locking pins52,53are moved out from the locking recesses24,25in the moveable guide10. After the locking pins52,53have been moved out from the locking recesses24,25, the control mechanism pulls the inner wire68of the third Bowden cable62which pulls the moveable guide10along the guide slot32to the second position, in which the moveable guide10is positioned over the second locking arrangement47.

When the moveable guide10is positioned over the second locking arrangement47, the control mechanism releases the inner wire66of the second Bowden cable61to allow the second U-shaped locking member49to move upwardly under influence of the bias of the springs58,59. The locking pins54,55are thus moved into the locking recesses24,25to lock the moveable guide10in the second position, as shown inFIG. 5.

Thus, it will be appreciated that the moveable guide10is moved by a drive arrangement from the first position to the second position in response to the child supporting squab4being moved from the retracted position to an operative position to provide the child supporting squab4in a position to accommodate a child.

If, subsequently, the vehicle seat1is to accommodate an adult, the movement mechanism is actuated, to pull the inner wire66of the second Bowden cable61, moving the second U-shaped locking member49downwardly, and hence moving the locking pins54,55out from the locking recesses24,25. The inner wire68of the third Bowden cable62is subsequently released by the control mechanism. The moveable guide10is thus free to move from the second position back to the first position under the force exerted by the biasing spring35when the third Bowden cable62is released by the control mechanism. Once the moveable guide10has moved back to the first position the inner wire64of the first Bowden cable60is released by the control mechanism and the first U-shaped locking member48moves upwardly under a biasing force exerted by the springs56,57so that the locking pins52,53move into the locking recesses24,25.

Referring now toFIGS. 8 and 9, an alternative embodiment of the invention utilises an electronic system to move the U-shaped locking members48and49, to unlock the moveable guide10. In this alternative embodiment, the first and second Bowden cables60and61are replaced by armatures84which are each mounted to the underside of a respective U-shaped locking member48,49. Each choke84passes through the small diameter aperture44,45in the base of the lock housing40,41, and each of the armatures84is biased upwardly, towards the moveable guide10by a resilient biasing strip85. A solenoid coil86is loosely wound around part of each of the armatures84, where each armature84passes through their respective small diameter aperture44,45,43. Each solenoid coil86is connected by wires to a circuit87which is positioned adjacent a pivoted lever76of the same configuration as the pivoted lever76of the preferred embodiment described above. The electrical circuit87incorporates a sensor88which senses the presence of the arm75of the pivoted lever76.

In this alternative embodiment, when a user moves the child supporting squab4from the retracted position to the operative position, the movement mechanism pivots the pivoted lever76which moves the arm75away from the sensor88. The sensor88provides a signal to the electronic circuit87and the electronic circuit87passes a current through one of the solenoid coils86. The current flowing through the solenoid coil86creates a magnetic field which pulls the armature84of the first locking arrangement downwardly, to pull the locking pins52,53out from the locking recesses24,25. A reader skilled in the art will appreciate that the armature84pulling the U-shaped locking member48downwardly is analogous to the inner wire64of the first Bowden cable60pulling the locking member48downwardly.

A further solenoid, or motor drive, may be provided to move the moveable guide10between its two positions.

Once each U-shaped locking member48,49has been moved to unlock the moveable guide10and after the moveable guide moved, the locking member48,49is subsequently moved back to a locking position by a force exerted by the corresponding biasing springs56-59. Thus, a reader skilled in the art will appreciate that the resilient biasing strip85is analogous to a pair of the biasing springs56,57or58,59.

Thus, a reader skilled in the art will appreciate that the mechanical arrangement involving the first and second Bowden cables60,61can be replaced with a system which uses solenoids to provide the same control for locking and unlocking the moveable guide10.

It is to be appreciated that in the embodiment described above a single restraint element, in the form of the moveable safety belt guide10is provided mounted on the seat back and moveable relative to the seat back in response to the seat being provided with a child squab to accommodate a child.

FIGS. 10 and 11illustrate a modified embodiment of the invention. InFIGS. 10 and 11many of the illustrated components correspond with components of the above described embodiments. These components will be identified using the same reference numerals and these components will not be redescribed at this time.

It is to be appreciated, fromFIGS. 10 and 11, that the embodiment of the invention now described incorporates a vehicle seat1having all of the features present in the embodiments ofFIGS. 1 to 9. However, the seat is provided with additional lateral restraint elements in the form of two restraint elements90,91which are initially mounted in a retracted position within the backrest3of the seat1, and two further restraint elements92,93which are initially mounted in position adjacent the ends of the headrest94provided at the top of the backrest3of the seat. The restraint elements90,91are provided with a drive arrangement to drive the restraint elements from an initial retracted position, as shown inFIG. 10, in which the restraint elements do not project at all from the backrest of the seat to an operative position, as shown inFIG. 11, in which the restraints extend forwardly of the backrest of the seat. Each restraint is in the form of a vertical panel, the vertical panels being located to respective sides of the child squab4, and being positioned so as to provide lateral restraint for the torso of a child sitting on the child squab.

Similarly the restraint element92,93associated with the headrest of the seat mounted for forward movement, the restraints, in this case, being mounted for pivotal movement about a pivot axis95located adjacent a forward lower part of the headrest. The restraint elements can therefore pivot forwardly, as indicated by the arrows96, until the restraint elements occupy the position illustrated inFIG. 11. The restraint elements92,93then project forwardly, one on either side of the headrest94, the restraint elements being positioned to provide lateral restraint for the head of a child sitting on the child squab4.

The restraint elements are each provided with an appropriate drive arrangement which is connected to the restraint element to move the restraint element from a first retracted or non-deployed position, as shown inFIG. 10to an extended or operative position, as shown inFIG. 11, in response to a seat being provided with a child squab to accommodate a child. The drive arrangement may be a wire linkage system incorporating a Bowden cable, which may be very closely associated with the Bowden cable arrangement provided to move the belt guide10. Alternatively, the drive arrangement may incorporate electrically actuable components such as solenoids or motors to drive the retaining elements from their first retracted position to their second extended or deployed position. Each restraint90,91,92,93may be provided with a locking member to lock it in the first position in the second position.

It is to be understood that whilst, in the embodiment described with reference toFIGS. 10 and 11, in response to the provision of the child squab the seat belt guide10effects a movement, and each of the retainer elements effects a movement, in a simpler embodiment of the invention a lesser number of moveable elements may be provided. Thus, it is conceivable that in a very simple embodiment of the invention only one lateral restraint element will be provided moveable from a retracted position to an extended position.

Whilst, in the embodiments described above the vehicle seat1has been a seat with an integrated moveable child supporting squab4, the vehicle seat1may alternatively be a standard vehicle seat, which does not incorporate an integrated moveable child supporting squab. In this case, a separate child squab may be provided on the squab2of the seat as a booster cushion to accommodate a child. In this case, the seat could be fitted with a sensor which senses the presence of a separate child supporting squab on the squab of the seat, with the sensor providing a signal to the drive arrangement to move the moveable lateral restraint or restraints10from the first position to the second position upon the seat being provided with the separate child supporting squab.

A reader skilled in the art will appreciate that a sensor for sensing the presence of a separate child supporting squab on a seat may take several forms. For instance, a Hall effect sensor could be installed within the squab2of the seat1to detect the presence of a magnet in the separate child supporting squab4when the child supporting squab4is placed on the squab2of the seat1. Alternatively, the seat may be provided with a mechanical arrangement, whereby a member on the separate child supporting squab presses a mechanical arrangement within the seat and the mechanical arrangement actuates the drive arrangement to move the moveable guide10from the first position to the second position. Thus a member on the separate child supporting squab4may engage a lever equivalent to the lever76.