GB2424177A

GB2424177A - Child seat mounting arrangement

Info

Publication number: GB2424177A
Application number: GB0427577A
Authority: GB
Inventors: John Davies
Original assignee: Nissan Motor Manufacturing UK Ltd; Nissan Technical Centre Europe Ltd
Current assignee: Nissan Motor Manufacturing UK Ltd
Priority date: 2004-12-16
Filing date: 2004-12-16
Publication date: 2006-09-20
Anticipated expiration: 2024-12-16
Also published as: GB0427577D0; GB2424177B

Abstract

A seat assembly for a vehicle comprises a passenger seat 10, means 20,42 for allowing back and forth movement of the passenger seat, and a mounting arrangement 32,36 for mounting a child seat 24 to the passenger seat so that, in use, the mounting arrangement is operative to allow mounting of the child seat on the passenger seat only in circumstances in which the passenger seat has been moved into or beyond a predetermined position. Also disclosed is a vehicle including an airbag control circuit which is deactivated in circumstances in which the mounting arrangement is operative, and a vehicle including a door lock control circuit which is activated to lock the door in such circumstances.

Description

VEHICLE SEAT ASSEMBLY

The invention relates to a seat assembly for use in a vehicle, and in particular to a seat assembly which is adaptable for use by a child. The invention finds particular benefit when employed in vehicles fitted with an airbag on the passenger side of the vehicle.

For babies and very young children, typically up to the age of 18 months, it is recommended for a child seat to be arranged in a rear-facing direction to the direction of travel. Furthermore, it is often desirable for the child seat to be located on the passenger seat of the vehicle, next to the driver, so that the driver has the child in view at all times.

Due to increasing vehicle safety standards it is becoming more common to provide a frontal airbag device on both the passenger's side of the vehicle and on the driver's side. It is recognised, however, that it is not safe to provide an airbag on the passenger side of the vehicle if a rear-facing child seat is to be mounted in the passenger seat.

Car manufacturers have developed one solution to address this incompatibility, and that is to disable permanently the passenger airbag at the time of vehicle sale if there is a likelihood that the buyer will wish to mount a child seat in the passenger seat. This operation can be performed at the factory or at the dealership, as necessary. However, this solution is not wholly desirable because, due to the permanent disabling of the passenger airbag, there is no facility to use a passenger airbag when an adult occupies the passenger seat. Furthermore, over the life of a vehicle it is likely that the requirements of the owner, or owners, may change, and there may be times when there is no longer a requirement to carry child passengers. The reverse problem also occurs if a vehicle does not have the passenger airbag disabled at the time of manufacture, but there later becomes a requirement to use a child seat in the passenger seat.

Another proposed solution is to provide the vehicle with a switch for allowing the user to disable or enable the airbag depending on whether a rear-facing child seat is to be used in the passenger seat. This solution is also undesirable, however, due to the risk of inadvertent disabling of the passenger airbag, forgetting to activate the passenger airbag after deliberate disabling, or vice versa.

One other problem facing vehicle manufacturers is the adaptability of vehicles for different situations. For example, although a vehicle user may wish to seat a child in the front passenger seat on some occasions, there may often be circumstances when an adult passenger must be seated there instead.

It is an object of the present invention to provide a seat assembly, suitable for accommodating a child, which seeks to address at least one of the aforementioned problems.

According to a first aspect of the present invention, there is provided a seat assembly for use in a vehicle, the seat assembly comprising a passenger seat and means for allowing the passenger seat to be moved back and forth. A mounting arrangement is provided for mounting a child seat to the passenger seat, in use, wherein the mounting arrangement is operative to allow mounting of the child seat on the passenger seat only in circumstances in which the passenger seat has been moved into or beyond a predetermined position.

In a preferred embodiment, the seat assembly includes means for permitting back and forth movement of the passenger seat between forward and rearward positions. Alternatively, or in addition, the seat assembly may include means for permitting back and forth sideways movement of the passenger seat.

In one preferred embodiment, the mounting arrangement is operative to allow mounting of the child seat on the passenger seat only in circumstances in which the passenger seat has been moved rearward into or beyond a predetermined position. This is particularly appropriate when the seat assembly is intended for use as a front passenger seat.

The reason why manufacturers do not typically allow the mounting of child seats in the front passenger seat is that it requires the child seat to be mounted too close to the likely location of the dashboard-mounted passenger airbag. In vehicles where front-seat mounting of the child seat is possible it is necessary to provide an airbag-disabling switch to be sure the device can be deactivated if the child seat is to be used. As described previously, this provides disadvantages, and particularly as inadvertent disabling of the switch, or forgetting to reactivate the switch, or vice versa, may occur. The problem is overcome in the present invention as mounting of the child seat is only permitted if the passenger seat has been displaced rearward from the passenger airbag beyond what is deemed to be a safe amount, leaving a sufficient gap between the airbag and the seated child to prevent injury in the event of airbag deployment. The requirement for a passenger airbag disabling switch is therefore removed.

In a further preferred embodiment, the seat assembly further includes means for locking the passenger seat against movement when the mounting arrangement is operative and the child seat is mounted upon the passenger seat. The provision of the locking means provides a further advantage as it prevents mis-use of the seat assembly, for example by sliding the passenger seat rearward beyond the predetermined position to allow mounting of the child seat but subsequently moving the passenger seat forward into an unsafe position.

In a further preferred embodiment, the mounting arrangement is changed between operative and inoperative positions by moving the mounting arrangement i.e. by changing its position.

In one embodiment, for example, the mounting arrangement is configured so that its height is changed between the operative and inoperative positions.

In a particularly preferred embodiment, the mounting arrangement is an ISOfix or a LATCH mounting arrangement which is well known in the automotive industry. The ISOfix mounting arrangement is adapted so as to provide the aforementioned functionality, whereby it can only be operated to mount a child seat to it when the passenger seat of the vehicle is considered to be at a safe distance from the passenger airbag mounted in the vehicle dashboard.

Preferably, the ISOfix mounting arrangement includes at least one ISOfix anchor, most preferably two anchors, for co-operation with a fixing means provided on the child seat when the mounting arrangement is in the operative position. The ISOfix anchor is movable between the operative position in which it can be coupled to the fixing means and the inoperative position in which coupling of the fixing means to the ISOfix anchor is prevented.

Preferably, the mounting arrangement further includes a shield member for shielding the ISOfix anchor from the fixing means on the child seat when the inoperative position is adopted.

In an alternative embodiment, the shield member of the mounting arrangement is movable into the operative position when the passenger seat is moved into or beyond the predetermined amount i.e. the shield is moved, rather than the ISOfix anchor.

The shield member is preferably provided with an opening which aligns with the ISOfix anchor when the operative position is adopted so as to provide access for the fixing means to the ISOfix anchor, and whereby the opening becomes mis- aligned with the ISOfix anchor when the inoperative position is adopted so as to prevent said access.

The seat assembly preferably includes a linkage means including a pivotally mounted lever which is operable to adjust the relative positions of the ISOfix anchor and the shield member, either by moving one or the other of them, or by moving both of them.

The locking means preferably takes the form of a locking pin which is coupled to the linkage means. The locking pin co-operates with a fixed part of the vehicle when the mounting arrangement is inoperative in a manner which allows sliding movement of the passenger seat. In addition, the locking pin co-operates with the fixed part of the vehicle when the mounting arrangement is operative in a manner which locks the passenger seat against movement beyond the predetermined position.

For example, the locking pin may be receivable within a channel defined in a passenger seat rail mounted on the floor of the vehicle, in use, to lock the passenger seat against further movement.

In a front seat application, the predetermined position of the passenger seat, namely that position forward of which it is considered unsafe to mount a child seat on the front passenger seat, may correspond to the passenger seat being at a rearmost end of its range of travel.

In an alternative embodiment, the predetermined position may correspond to the passenger seat being a short distance in front of a rearmost end of its range of travel. This is because in some vehicles there is a large enough space between the passenger seat and the frontal airbag to allow the passenger seat to take up a position slightly forward of its rearmost position, whilst still carrying a child seat occupant safely.

The invention also has application in the rear passenger seats of a vehicle, and in particular passenger seats which are arranged between the front row of seats and the third (typically rear) row of seats. It is often desirable to locate the passenger seat of the middle row such that, when the child seat is mounted upon it, the rear of the seat back of the child seat rests against, or abuts, the rear of the front passenger seat. This provides additional support for the child seat, and ensures the child seat is near to a rigid structure (i.e. the front seat), which is beneficial especially if a side curtain airbag is provided in the vehicle. However, in order to mount the child seat in the middle row of vehicle seats, extra room may be required between the front passenger seat and the intermediate row of seats if the child seat is to be manoeuvred conveniently during mounting. It is therefore desirable for the passenger seat to be moveable, over a short region forward from the predetermined position, once the child seat has been mounted on the operative mounting arrangement. In this embodiment, therefore, the "predetermined position" is defined at the rear end of a predetermined range of movement of the passenger seat, that is at the rear end of a discrete region of the total range of movement.

Rearward movement of the passenger seat beyond the predetermined position is prevented once the child seat is mounted upon the passenger seat. Additionally, in circumstances in which the passenger seat is rearward of the predetermined position, the mounting arrangement is rendered inoperative so that the child seat cannot be mounted upon it.

In this particular embodiment, therefore, the locking pin and the fixed part of the vehicle may be configured to permit movement of the passenger seat over a predetermined region of movement, forward of the predetermined position, even in circumstances in which the mounting arrangement is operative and the child seat is mounted upon the passenger seat.

In an embodiment in which the passenger seat is movable back and forth sideways, or laterally, within the vehicle, the mounting arrangement is operative to allow mounting of the child seat on the passenger seat only in circumstances in which the passenger seat is moved laterally (sideways) away from the vehicle side, into or beyond a predetermined position.

This embodiment of the invention finds particular application in the middle or rear row of seats of a vehicle, and especially in vehicles provided with a side curtain airbag where it is desirable to seat child passengers beyond a predetermined, safe distance from the side curtain airbag.

The linkage means may include one or more of the following: an hydraulic arrangement, a magnetic arrangement, an electrical arrangement, a mechanical linkage means. Other forms of linkage are also envisaged.

The seat assembly may further comprise a switch means which is coupled to the mounting arrangement and operable between an active state in circumstances in which the mounting arrangement is inoperative and an inactive state in circumstances in which the mounting arrangement is operative.

For example, the switch means may form a part of a passenger airbag control circuit. The seat assembly may further comprise means for detecting whether or not a child seat is mounted upon the mounting arrangement, whereby in circumstances in which the mounting arrangement is operative and it is detected that the child seat is mounted on the mounting arrangement, the switch means is in the inactive state so as to disable an airbag of the vehicle.

In another implementation, the passenger seat may be movable by electrical means including an electric seat control circuit, and the switch means may form a part of the electric seat control circuit. In circumstances in which the mounting arrangement is operative, the switch means is in the inactive state so as to disable operation, and hence movement, of the electric seat.

According to a second aspect of the invention, there is provided a vehicle including a passenger airbag, a seat assembly of the first aspect of the invention and an airbag control circuit which is deactivated in circumstances in which the mounting arrangement is operative, so as to prevent deployment of the airbag in such circumstances.

In this aspect of the invention, therefore, the airbag disabling switch itself forms a part of the invention.

According to a third aspect of the invention, there is provided a vehicle including a seat assembly of the first aspect of the invention, an electrically operable door lock means for a vehicle door and a door lock control circuit for controlling locking and unlocking of the vehicle door from inside the vehicle. The door lock control circuit is activated in circumstances in which the mounting arrangement of the seat assembly is operative and it is detected that a child is occupying the seat, so as to prevent inadvertent opening of the vehicle door from the vehicle interior in such circumstances.

This aspect of the invention therefore incorporates a functionality of a front door child lock.

It will be appreciated that preferred and/or optional features of the seat assembly of the first aspect of the invention may be provided in the vehicle of the second aspect of the invention also, either alone or in appropriate combination.

The invention will now be described, by way of example only, with reference to the following figures in which: Figure 1 is a schematic side view of a first embodiment of the invention in which the passenger seat is in a first, relatively rearward position in which a mounting arrangement for the child seat is operable to allow mounting of the child seat on the passenger seat, Figure 2 is a schematic side view of the passenger seat in Figure 1 when in a relatively forward position, in which the mounting arrangement of the passenger seat is inoperable to prevent mounting of the child seat on the passenger seat, Figure 3 is an enlarged schematic view of the mounting arrangement for the child seat when the passenger seat adopts the rearward position of Figure 1, Figure 4 is an enlarged schematic view of the mounting arrangement in Figure 3 when the passenger seat adopts the forward position of Figure 2, Figure 5 is a schematic side view of a second embodiment of the invention in which the passenger seat is in a first, relatively rearward position in which a mounting arrangement for the child seat is operable to allow mounting of the child seat on the passenger seat, Figure 6 is a schematic side view of the passenger seat in Figure 5 when in a relatively forward position, in which the mounting arrangement of the passenger seat is inoperable to prevent mounting of the child seat on the passenger seat, Figure 7 is an enlarged schematic view of the mounting arrangement for the child seat when the passenger seat adopts the rearward position of Figure 5, Figure 8 is an enlarged schematic view of the mounting arrangement in Figure 7 when the passenger seat adopts the forward position of Figure 6, and Figure 9 is a schematic diagram to illustrate a switch means which may form a part of the embodiment of Figures 1 to 4, or the embodiment of Figures 1 to 8.

Referring to Figure 1, a seat assembly for use in a vehicle includes a passenger seat assembly, referred to generally as 10, having a generally level seat cushion 12 and a generally upright seat back 14, which meet at an intersection towards the rear of the seat cushion 12 and the lower part of the seat back 14. The seat cushion 12 is mounted upon a seat base 16, which attaches to the floor pan 18 of the vehicle via a guide or rail mechanism 20 to allow the seat assembly 10 to be moved back and forth, in rearward and forward directions respectively, in the manner of a conventional vehicle seat. Each rail mechanism 20 typically includes is first and second seat rails which are fixed to the vehicle floor pan, one on either side of the seat. In the side view of Figure 1 only a single rail is visible (indicated at 20). The passenger seat base 16 is provided with runners (not shown) which co-operate with the rails 20 during back and forth seat motion, in a conventional manner.

A handle or manual seat adjuster 22 is provided on the front of the seat base 16 to facilitate manoeuvring of the seat assembly 10 back and forth by disabling a locking arrangement (not shown). The manual seat adjuster operates in a known manner so that, when operated, combs or slider locks of the locking arrangement become disengaged from correspondingly formed slots provided in the seat rail.

Once the desired seat position has been reached, the adjuster is released so that the combs are urged back into their slots to secure the passenger seat in the desired position.

A passenger airbag device (not shown) is typically mounted upon the dashboard of the vehicle, forward of the passenger seat 10 and spaced apart from the seat 10 by a variable amount, depending on the position of the seat 10.

The passenger seat 10 is adapted to support a child seat 24 in a rear- or forward- facing orientation. In the illustration shown, the child seat 24 provides a rear- facing seat position for the child. The child seat 24 has a seating portion 26, upon which a child passenger sits, a seat base 28 which supports the seating portion 26 and a back rest portion 30.

The passenger seat 10 is provided with a mounting arrangement which enables secure mounting of the child seat 24 to the passenger seat 10. Typically, the mounting arrangement takes the form of an ISOfix compliant mounting arrangement, including first and second ISOfix anchors 32 (only the first one of which is shown in the side view) which are located in the region of intersection between the lower part of the seat back 14 and the rear part of the seat cushion 12. The ISOfix child seat system is an automotive industry standard proposed by the United Nation Economic Commissions for Europe, and ISOfix compliant mounting arrangements would be well known to a person skilled in this art. In the United States, the ISOfix mounting arrangement is commonly known as the LATCH mounting arrangement.

The first and second ISOfix anchors 32 are co-operable with a fixing means, in the form of first and second fixing bars 34 respectively (only one of which is shown), which are provided on the child seat 24. The fixing bars 34 of the child seat 24 co-operate with the ISOfix anchors 32 in a conventional manner.

Typically, a release handle 36 is provided on the child seat 24, which is operable to permit detachment of the fixing bars 34 from the ISOfix anchors 32 when the child seat 24 is to be removed from passenger seat 10. The release handle 36 is located at the rear edge of the child seat base 28.

It is a particular characteristic of the seat assembly that the ISOfix mounting arrangement 32 has two different states, depending upon the axial position of the passenger seat 10 along the rail mechanism 20. Referring to Figure 1, when the passenger seat 10 adopts a fully rearward position along the rails 20, the ISOfix anchors 32 are in an operative' state in which the fixing bars 34 of the child seat 24 may be attached to their respective anchors 32. Referring to Figure 2, when the passenger seat 10 adopts a fully forward position along the rails 20, the ISOfix anchors 32 are in an inoperative' state in which the anchors 32 are shielded so that it is not possible to attach the child seat fixing bars 34 to them.

The manner in which the anchors 32 are altered between the operative and inoperative states will now be described in further detail with reference to Figures 3 and 4. For the sake of simplicity, only one of the ISOfix anchors 32 and its associated fixing bar 34 will be described in detail.

Referring to Figure 3, the mounting arrangement further includes a shield member 36 provided with an opening 38 to permit access to the ISOfix anchor 32 only in circumstances in which the anchor 32 is moved into a position which corresponds to the fully rearward position of the passenger seat 10. A coupling means in the form of a mechanical linkage 40 couples the ISOfix anchor 32 to a locating feature 42, in the form of a locking pin, which co-operates with the floor-mounted rail 20 and slides back and forth along it as the passenger seat 10 is moved. The linkage 40 is configured to allow the height of the ISOfix anchor 32 above the rail 20 (i.e. above the vehicle floor) to be adjusted, depending on the position of the passenger seat 10 along the rail 20.

The linkage 40 includes a movable lever 44, one end of which is attached to the ISOfix anchor 32 and the other end of which is attached to a pivotal support 46 in fixed connection with a part of the passenger seat 10. An intermediate element 48 connects the pivotal support 46 for the lever 44 to a linkage support 50 which carries, at its end remote from the intermediate element, the locking pin 42. The locking pin 42 is receivable within an appropriately shaped groove or channel 52 provided in the rail 20.

The linkage support 50 is biased downwards by means of a spring 54 so that, when the passenger seat 10 is in its fully rearward position (as shown in Figure 3), the locking pin 42 is urged into, and retained within, the channel 52 by means of the spring force. With the linkage support 50 urged downwards, the lever 44 is caused to pivot upwards about the support 46, and thus the ISOfix anchor 32 adopts an elevated or raised position in which it is presented to, or aligned with, the opening 38 in the shield 36. This is the operative position of the mounting arrangement (as shown in Figure 3), in which the fixing bar 34 of the child seat 24 may be received through the shield opening 38 to co-operate with the ISOfix anchor 32, thereby allowing secure fixing of the child seat 24 to the passenger seat 10.

As shown in Figure 4, when the passenger seat 10 is positioned in the fully forward position, the locking pin 42 is raised out of the channel 52 to rest against the upper surface of the rail 20. This is achieved by lifting the linkage support 50 against the force of the spring 54, so that the locking pin 42 can be dislodged or disengage from the channel 52 as the seat 10 is moved forwards along the rail 20.

As a result of the linkage 40 being lifted upwards, the lever 44 is caused to pivot downward about the support 46 so that the ISOfix anchor 32 is lowered to reduce its height above the rail 20. This is the inoperative position of the mounting arrangement, in which the ISOfix anchor 32 is hidden or shielded behind the shield 36 (i.e. mis-aligned with the opening 38) so that the ISOfix anchor 32 is not accessible to the fixing bar 34 of the child seat 24.

In order to move the passenger seat 10 between the position shown in Figure 3 and that shown in Figure 4, it will be appreciated that the child seat fixing bar 34 must first be removed from the ISOfix anchor 32 so that the linkage 40 can be raised upwards, against the biasing force of the spring 54, to allow the locking pin 42 to dislodge from the channel 52. To aid movement of the locking pin 42 out of the channel 52 in such circumstances, the channel 52 is preferably shaped to define a ramped surface (not indicated) along which the locking pin 42 can slide.

It will be appreciated that in the position shown in Figure 3, the locking pin 42 is effectively jammed' or locked' within the channel 52. Thus, forward movement of the passenger seat 10 within the rails 20 is not possible unless the child seat 24 is first detached from the ISOfix anchors 32. Only when the child seat 24 is detached from the mounting arrangement 32 does the linkage 40 have the freedom to be raised upwards, thereby allowing the locking pin 42 to be moved out of the channel 52 and allowing movement of the seat 10 in a forward direction along the rail 20.

From the foregoing description it will be appreciated that an advantage of the present invention is that the child seat 24 can only be fixed to the passenger seat 10, by virtue of the fixing bars 34 co-operating with the ISOfix anchors 32, in circumstances in which the seat 10 occupies its fully rearward position along the rail 20. In this position, the passenger seat 10 is separated from the passenger airbag by a safe distance. In circumstances in which the passenger seat 10 is moved forwards along the rails 20, out of its fully rearward position, the ISOfix anchors 32 become inaccessible, and hidden from view, to prevent a child seat 24 being mounted upon the passenger seat in circumstances in which the passenger seat 10 is too close to the passenger airbag for safe mounting of the child seat 24.

It is a further benefit that once the child seat 24 is mounted upon the passenger seat 10 in its fully rearward position, the passenger seat 10 cannot then be moved forwards, deliberately or inadvertently, as the locking pin 42 becomes locked within the channel 52 to prevent such movement.

Figures 5 and 6 illustrate an alternative embodiment of the invention in which the mounting arrangement consists of a static, or rigidly fixed, ISOfix anchor 32 and a movable shield member 36. In practice, the embodiment of Figures 5 and 6 may be preferred, as it is easier to engineer strength into a static component than a movable one, and it is the ISOfix anchor 32 which has the greater strength requirement. The height of the shield 36 above the rail 20 is adjustable as the passenger seat 10 is moved back and forth along the rail 20, so in this embodiment it is the shield 36 that is movable between inoperative and operative states. As shown in Figure 5, when the passenger seat 10 is fully rearward and in a safe position to carry the child seat 24, the shield 36 adopts a raised position in which the child seat fixing bar 34 can be attached to the ISOfix anchor 32.

Conversely, as shown in Figure 6, when the passenger seat 10 is moved forwards, the shield 36 adopts a lowered position in which attachment of the child seat fixing bar 34 to the ISOfix anchor 32 is prevented.

Figures 7 and 8 illustrate the second embodiment of the invention in more detail.

In this case, the shield 36 is coupled to the locking pin 42 via the linkage 40 so that when the locking pin 42 rests within the channel 52 with the passenger seat 10 in the fully rearward position, the opening 38 in the shield 36 aligns with the fixed ISOfix anchor 32 to allow the child seat fixing bar 34 to be attached to the anchor 32. If the child seat fixing bar 34 is detached from the ISOfix anchor 32, as shown in Figure 8, the linkage 40 can be lifted upwards, against the force of the spring 54, thereby causing the lever 44, and hence the shield 36, to pivot downwards about the support 46. As the shield 36 is lowered, the opening 38 is moved out of alignment with the ISOfix anchor 32, thus preventing re-attachment of the child seat fixing bar 34 to the anchor 32.

As in the previous embodiment, when the passenger seat 10 is fullyrearwards with the child seat fixing bars 34 attached to the ISOfix anchors 32, it is not possible to move the passenger seat 10 forwards due to the locking pin 42 being engaged within the channel 52 in the rail 20. Only when the child seat 24 is detached from the ISOfix anchors 32 is the passenger seat 10 able to be slid forwards, by raising the linkage 40 upwards and urging the locking pin 42 to move up and out of the channel 52.

Alternative embodiments of Figures 1 to 4 are also envisaged in which, for * example, the shields 36 are not movable by means of a mechanical linkage 40 coupled to the locking pin 42, but in which another form of coupling is provided.

For example, the shields 36 may be movable by means of an hydraulic arrangement, a gear arrangement, a magnetic arrangement or an electrical arrangement.

In all instances, the important feature is provided that movement of the shields 36 to block access to the ISOfix anchors 32 occurs as soon as the passenger seat 10 is moved in a forward direction beyond what is considered to be the predetermined, minimum safe distance, between the passenger seat 10 and the passenger airbag, at which a child seat 24 can be mounted safely on the seat 10.

In an alternative embodiment, for example, the shields 36 may be movable by means of an electromagnetic actuator, or actuators. The actuator(s) is only activated to move the shields 36 into a position to expose the ISOfix anchors 32 in circumstances in which the passenger seat 10, and hence the locking pin 42, is moved rearward along the rail 20 to a position beyond the predetermined, minimum safe distance from the passenger airbag. The passenger seat 10 may be provided with a switch means that is closed to activate the actuator, and thus expose the anchor 32 for mounting of the child seat, when the passenger seat 10 has reached the predetermined safe distance.

In a similar manner, the embodiments of Figures 5 to 8 may also include means other than a mechanical linkage 40 for coupling the movable shield 36 to the locking pin 42.

In some vehicles, it may not be necessary for the inoperative state of the mounting arrangement 32, 36 to correspond to the fully rearward position of the passenger seat 10. In practice, the predetermined safe distance between the passenger seat 10 and the airbag will depend upon the space available within the cabin. In larger vehicles, for example, it may be that for positions of the passenger seat 10 beyond, say, three quarters of its total range of travel along the rails 20, it is safe for the child seat 24 to be mounted on the passenger seat 10.

In a further alternative embodiment (not shown), the linkage 40 may be configured to move between different lateral positions, as opposed to adjusting its height, so as to switch between the operative and inoperative states of the mounting arrangement 32, 36. As the fixing bars 34 of the child seat 24 are in fixed positions, lateral movement of the ISOfix anchors 32, either to increase or decrease their separation, will prevent the fixing bars 34 being attached thereto.

In a still further alternative embodiment (not shown), the vehicle may be provided with a controller for controlling the passenger airbag system, including a sensor for detecting the position of the passenger seat 10 along the rails 20 and a means for detecting when the child seat 24 is affixed to the mounting arrangement 32.

The position of the passenger seat 10 is detected and the controller provides a control signal to disable the passenger airbag in circumstances in which (i) it is determined that the child seat 24 is mounted on the passenger seat 10 and (ii) the passenger seat 10 adopts a position sufficiently rearward for the mounting arrangement 32, 36 to be rendered operative. Thus, if a child seat 24is mounted upon the passenger seat 10 when it adopts a position at, or rearward of, the predetermined safe distance, the passenger airbag will automatically be disabled.

Therefore, there are no circumstances in which a child seat 24 can be mounted upon the passenger seat 10 with the passenger airbag enabled. This may be particularly useful in smaller vehicles, for example, where the space available in the vehicle cabin does not permit the passenger seat 10 to be moved far enough rearward to exceed what is considered to be the predetermined, safe distance for mounting of a child seat 24.

Figure 9 shows a less sophisticated implementation of the aforementioned embodiment, based on a seat assembly 10 having a movable ISOfix anchor (not shown in Figure 9) as in Figures 1 to 4. A switch means 60 is provided on the seat assembly 10 which forms a part of the vehicle's airbag control circuit. The switch means 60 includes a pivotally movable switch 62, mounted on the shield 36, which is co-operable with a corresponding, fixed switch contact (not shown) mounted on a fixed part of the seat. The switch means has an active state, in which the movable switch 62 makes contact with the switch contact to complete an electrical circuit, and an inactive state in which the movable switch 62 is disengaged from the fixed switch contact to break the electrical circuit.

When the passenger seat 10 is moved rearwards sufficiently far to allow the child seat fixing bar 34 to be attached to the ISOfix anchor 32, the movable switch 62 is caused to move pivotally out of engagement with the fixed contact switch, thus disabling the airbag control circuit.

In a further alternative embodiment, the switch means 60 on the passenger seat 10 is coupled electrically to the vehicle door locking circuit, so that when the airbag is disabled (i.e. when the child seat 24 is mounted on the passenger seat 10), the lock on the adjacent vehicle door is activated. This provides an increased safety measure for the child passenger. In this embodiment, therefore, the switch means forms a part of the door lock control circuit.

In vehicles fitted with electrically operated seats, the switch arrangement may also, or in addition, be coupled to the vehicle's electric seat control circuit so that, when the child seat 24 is mounted on the passenger seat 10, the electric seat circuit is disabled to prevent any forward movement of the passenger seat 10 until the child seat 24 is dismounted.

The invention may also be used in the rear passenger seats, typically in multi- person vehicles (MPVs), for example, such as those have three rows of seats; a front row, a middle row, and a back or rear row. It is often desirable for the child seat to be mounted on the middle row of seats, leaving the front passenger seat vacant for a second adult passenger but keeping the child in close proximity to the front-seated adult passengers at the same time. For safety reasons, it is also preferable for the child seat to take up a rear-facing position for transit in which its seat back rests against the rear-facing surface of the front passenger seat.

The invention can be adapted for use in the middle or rear row of a vehicle by ensuring the mounting arrangement only becomes operative when the passenger seat is moved in a forward direction beyond a predetermined amount so as to ensure a short distance is maintained, between the front seat and the middle row of seats, if a child seat is to be mounted on the passenger seat. However, it is not often possible to mount the child seat on the passenger seat in the middle row when the passenger seat is moved so far forward. It is therefore desirable to be able to mount the child seat on the passenger seat when the passenger seat is displaced a short distance rearward of the ideal position for transit, and to allow movement of the passenger seat in a forward direction, over a restricted range of movement, when the child seat has been mounted.

In this embodiment, therefore, the seat assembly is adapted to move the ISOfix anchors 32 and/or the shields 36 into the operative position when the passenger seat 10 is moved in a forward direction beyond a predetermined amount.

Furthermore, the mounting arrangement 32, 36 is operative over a range of movement of the passenger seat 10, forward of the predetermined position, rather than being operative at just a single position of the passenger seat 10. Thus, once the child seat 24 has been mounted on the passenger seat 10 by means of the operative ISOfix anchors 32, the passenger seat 10 is still permitted to move a short way forward, through a discrete range of travel, to allow the seat 10 to take up a safer position for the purposes of transit.

Movement of the passenger seat in a rearward direction, beyond the predetermined position, is prevented once the child seat is mounted upon the passenger seat 10, so as to be sure that the favoured forward position of the passenger seat is maintained during transit.

A further alternative embodiment is proposed in which a lateral movement of the passenger seat is possible. This may be desirable in vehicles fitted with side curtain airbags, for example, where a child seat is to be mounted on the rear passenger seat. Mounting of the child seat on the operative mounting arrangement is only permitted in circumstances in which the passenger seat is displaced laterally, or sideways, away from the vehicle side, beyond what is determined to be a safe distance between the child seat and the side curtain airbag.

Claims

1. A seat assembly for use in a vehicle, the seat assembly comprising: a passenger seat (10), means (20, 42) for allowing back and forth movement of the passenger seat, and a mounting arrangement (32, 36) for mounting a child seat (24) to the passenger seat (10), in use, wherein the mounting arrangement (32, 36) is operative to allow mounting of the child seat (24) on the passenger seat (10) only in circumstances in which the passenger seat (10) has been moved into or beyond a predetermined position.

2. The seat assembly as claimed in claim 1, wherein the mounting arrangement (32, 36) is operative to allow mounting of the child seat (24) on the passenger seat (10) only in circumstances in which the passenger seat (10) has been moved in a rearward direction into or beyond the predetermined position.

3. The seat assembly as claimed in claim 2, wherein the predetermined position corresponds to the passenger seat (10) being at a rearmost end of its range travel.

4. The seat assembly as claimed in claim 2, wherein the predetermined position corresponds to the passenger seat (10) being a short distance forward of a rearmost end of its range of travel.

5. The seat assembly as claimed in claim 1, wherein the mounting arrangement (32, 36) is operative to allow mounting of the child seat (24) on the passenger seat (10) only in circumstances in which the passenger seat (10) has been moved in a forward direction into or beyond the predetermined position.

6. The seat assembly as claimed in any one of claims 1 to 5, wherein the means for allowing passenger seat movement includes means for allowing the io passenger seat to be moved laterally, wherein the mounting arrangement is operative to allow mounting of the child seat on the passenger seat only in circumstances in which the passenger seat is moved laterally away from a side of the vehicle into or beyond the predetermined position.

7. The seat assembly as claimed in any one of claims 1 to 6, further comprising locking means for locking the passenger seat (10) against further movement when the mounting arrangement (32, 36) is operative and the child seat (24) is mounted upon the passenger seat.

8. The seat assembly as claimed in claim 7, wherein the mounting arrangement (32, 36) is changed between operative and inoperative positions by moving of the mounting arrangement.

9. The seat assembly as claimed in claim 8, whereby the height of the mounting arrangement (32, 36) is changed as the mounting arrangement moves between the operative and inoperative positions.

10. The seat assembly as claimed in claim 8 or claim 9, wherein the mounting arrangement is an ISOfix or a LATCH mounting arrangement (32, 36) .

11. The seat assembly as claimed in claim 10, wherein the ISOfix mounting arrangement includes at least one ISOfix anchor (32) for co-operation with a fixing means (34) provided on the child seat (24) when the mounting arrangement is in the operative position.

12. The seat assembly as claimed in claim 11, wherein the ISOfix anchor (32) is movable between the operative position in which it can be coupled to the fixing means (34) and the inoperative position in which coupling of the fixing means (34) to the ISOfix anchor (32) is prevented.

13. The seat assembly as claimed in claim 12, wherein the mounting arrangement includes a shield member (36) for shielding the ISOfix anchor (32) from the fixing means (34) on the child seat (24) when the inoperative position is adopted.

14. The seat assembly as claimed in claim 11, wherein the mounting arrangement includes a shield member (36) for shielding the ISOfix anchor (32) when the inoperative position of the mounting arrangement is adopted, the shield member (36) being movable into the operative position when the passenger seat (10) is moved into or beyond the predetermined amount.

15. The seat assembly as claimed in claim 13 or claim 14, wherein the shield member (36) is provided with an opening (38) which aligns with the ISOfix anchor (32) when the operative position is adopted so as to provide access for the fixing means (34) to the ISOfix anchor (32), and whereby the opening (38) becomes mis-aligned with the ISOfix anchor (32) when the inoperative position is adopted so as to prevent said access.

16. The seat assembly as claimed in any one of claims 13 to 15, including a linkage means (40) which is operable to adjust the relative positions of the shield member (36) and the ISOfix anchor (32), either by moving the ISOfix anchor (32) or the shield member (36) or both, the mechanical linkage means (40) including a pivotally mounted lever (44) which is operable to adjust the position of the ISOfix anchor (32) and/or the shield member (36).

17. The seat assembly as claimed in claim 16, wherein the locking means includes a locking pin (42) which is coupled to the linkage means (40), the locking pin (42) co-operating with a fixed part (20) of the vehicle when the mounting arrangement (32, 36) is inoperative so as to permit sliding movement of the passenger seat (10) relative to the fixed part (20).

18. The seat assembly as claimed in claim 17, wherein the locking pin (42) co- operates with the fixed part (20) of the vehicle when the mounting arrangement (32, 36) is operative to lock the passenger seat (10) in position.

19. The seat assembly as claimed in claim 17 or claim 18, wherein the locking pin (42) is receivable within a channel (52) defined in a vehicle floor mounted rail or guide (20), thereby to lock the passenger seat (10) against further movement.

20. The seat assembly as claimed in any one of claims 16 to 19, wherein the linkage means includes one or more of the following: an hydraulic arrangement, a magnetic arrangement, an electrical arrangement, a mechanical linkage means (40).

21. The seat assembly as claimed in any one of claims 1 to 20, further comprising a switch means (60) coupled to the mounting arrangement (32, 36) and operable between an active state in circumstances in which the mounting arrangement (32, 36) is inoperative and an inactive state in circumstances in which the mounting arrangement (32, 36) is operative.

22. The seat assembly as claimed in claim 21, wherein the switch means (60) forms a part of a passenger airbag control circuit, the seat assembly further comprising means for detecting whether or not a child seat is mounted upon the mounting arrangement, whereby in circumstances in which the mounting arrangement (32, 36) is operative and it is detected that the child seat is mounted upon the passenger seat (10), the switch means is in the inactive state so as to disable an airbag of the vehicle.

23. The seat assembly as claimed in claim 21 or claim 22, wherein the passenger seat (10) is movable by electrical means including an electric seat control circuit, wherein the switch means (60) forms a part of the electric seat control circuit, whereby in circumstances in which the mounting arrangement (32, 36) is operative and the child seat is mounted upon the passenger seat (10), the switch means (60) is in the inactive state so as to disable operation, and hence movement, of the electric seat.

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24. A vehicle including: a passenger airbag, a seat assembly (10) as claimed in any one of claims 1 to 23, and an airbag control circuit which is deactivated in circumstances in which the mounting arrangement (32, 36) of the seat assembly is operative to prevent deployment of the airbag in such circumstances.

25. A vehicle including: a seat assembly (10) as claimed in any one of claims 1 to 23, an electrically operable door lock means for a vehicle door, and a door lock control circuit for controlling locking and unlocking of the vehicle door from inside the vehicle, the door lock control circuit being activated in circumstances in which the mounting arrangement (32, 36) of the seat assembly is operative, thereby to prevent inadvertent opening of the vehicle door from the vehicle interior in such circumstances.