[001] The present invention relates to a seat mounting for a child safety seat.

[002] Child safety seats which can be attached to passenger seats (vehicle seats) in cars are known. Problems can arise where cars are provided with air bag systems and other supplementary restraint systems such as seat belt tensioners for the protection of adult passengers. Such systems can be inappropriate, or even dangerous, when a child in a safety seat is present, rather than an adult. In particular, deployment of an air bag can be highly dangerous to a child in a (rear facing) safety seat.

[003] To address this problem, sensing systems for determining the presence of a safety seat placed on a passenger seat in a car are known. Such sensing systems take the form of antennas incorporated in the passenger seat which interact with one or more resonators located in the safety seat. In this way, the sensing system is able to determine whether or not the safety seat is present, and to send this information to a controller for controlling the deployment of various supplementary restraint systems. Thus, in the example of an air bag deployment system, the air bag can be allowed to deploy normally if a safety seat is not present on the vehicle seat, or can be prevented from deploying if a child seat is present.

[004] Certain types of safety seat are attached to the passenger seat, via a separate mounting unit (seat mounting/supporting base) . In this case, the mounting unit, rather than the child seat, is attached to the vehicle seat, and the child seat is releasably mounted to the mounting unit. Such mounting units are designed to be placed over

the vehicle seat base, and may be attached thereto using an isofix-type latch system, or the seat belt of the vehicle seat. Thus, in use, the mounting unit is interposed between the child seat and the vehicle seat base.

[005] For the above described sensing system to work with such safety seats, it has previously been necessary for the resonator to be located in the mounting unit rather than the safety seat. This is because, with the resonator located in the safety seat, the mounting unit acts as a screen (obstacle) which disrupts interaction with the resonator, such that it can not operate satisfactorily.

[006] Certain types of safety seat may be used with or without a mounting unit. In these cases it is clearly necessary for a resonator to be located in the safety seat, so that the safety seat can be detected when the mounting unit is not present.

[007] However, including resonators in both the safety seat and the mounting unit can be problematic, due to interference between the resonators.

[008] It is an object of the present invention to overcome the aforementioned problems.

[009] According to the present invention there is provided a seat mounting for mounting a child safety seat on a vehicle seat, the seat mounting comprising:- coupling means for releasably holding the child safety seat; and a window for providing a detection path between the mounted child safety seat and a detector element provided in the vehicle seat. In this manner, the presence of a child safety seat can be readily detected, despite the presence of the seat mounting between the child safety seat and the vehicle seat.

[0010] According to a further aspect of the present invention, there is provided a seat mounting for locating a child safety seat on a vehicle seat, the seat mounting comprising:- coupling means for releasably receiving the child safety seat; and a window for allowing the presence of a detection element located in a child safety seat attached to the seat mounting to be detected through the seat mounting by a detector element provided in the vehicle seat. As such, the window provides enhanced detection of the child safety seat, when mounted.

[0011] The window is preferably substantially transparent to electromagnetic radiation. Hence, an inductively coupled detection system may be employed.

[0012] Conveniently, the window forms a blind hole within the seat mounting. Alternatively, the window forms an aperture through the seat mounting. In both cases, the detection element provided in the child safety seat can be brought close to the detector element provided in the vehicle seat. This allows electromagnetic radiation levels to be reduced.

[0013] Preferably, upper edges of the window are profiled for guiding a seat into engagement with the seat mounting. The upper edges of the window may be tapered and/or curved.

[0014] The seat mounting is preferably symmetrical about at least one axis for allowing a seat to be mounted thereon in more than one orientation.

[0015] In this regard, the seat mounting can have front and rear ends, the window being symmetrical for allowing a child safety seat to be mounted in either forward or rearward

facing directions.

[0016] The seat mounting can be attachable to a child safety- seat by means of a socket and ball mechanism. The male part of the socket and ball mechanism is conveniently on the seat mounting,- whilst the female part is conveniently on the child safety seat.

[0017] According to a further aspect of the present invention there is provided a child safety seat for use in combination with the seat mounting defined above, wherein the child safety seat comprises a detection element for detection by the detector element of the vehicle seat, the detection element being provided asymmetrically within a window engaging component.

[0018] Preferably, the window engaging component comprises a protrusion having a substantially complementary profile to the window. The coupling between the protrusion and the window provides a secure mounting between the child safety seat and the seat mounting.

[0019] • Conveniently, the detection element is provided at or adjacent an outer surface of the window engaging component. This allows the detection element of the child safety seat to be brought close to the detector element provided in the vehicle seat, thereby permitting electromagnetic radiation levels to be reduced.

^' [0020] The child safety seat can be attachable to a seat mounting by means of a socket and ball mechanism. The male part of the socket and ball mechanism is conveniently on the seat mounting, whilst the female part is conveniently on the child safety seat.

^• _ c _

[0021] The present invention will now be described with reference to the following drawings in which: -

[0022] Figure 1 shows a side view of a seat mounting embodying the present invention;

[0023] Figure 2 shows the seat mounting of figure 1 with a child safety seat mounted therein in a forward facing direction;

[0024] Figure 3 shows the seat mounting of figure 1 with a child safety seat mounted therein in a rearward facing direction;

[0025] Figure 4 shows a plan view from above of the seat mounting;

[0026] Figure 5 shows a plan view from beneath of a child safety seat for use with the seat mounting;

[0027] Figure β shows a schematic view of an inductively coupled system for use with the present invention;

[0028] Figure 7 shows a side view of a further embodiment of a seat mounting of the present invention;-

[0029] Figure 8 shows a side view of the embodiment of figure 7 with the seat in a mounted position; and

[0030] Figure 9 shows a side view of a further seat mounting having alternative vehicle seat mounting means, namely means for engaging a vehicle seat belt.

[0031] Figures I ₁ 2 and 3 are side views of a mounting unit 1 embodying the present invention attached to a vehicle seat

2. Figure 1 shows a safety seat 6 dismounted from the mounting unit 1, whilst figures 2 and 3 show the safety seat 6 mounted on the mounting unit 1 in different orientations.

5 [0032] As can be seen from figures 1 and 2, the mounting unit 1 is attached to the vehicle seat via a pair of isofix latch systems 3 (only one shown) in a known manner. The mounting unit 1 extends over the base of the vehicle seat 2, and overhangs the front edge thereof. A foot prop 4, 10 extends downwardly from the overhang to the floor to support the mounting unit 1 in position.

[0033] The mounting unit 1 is provided with a rectangular recess 5 (see figure 4) for receiving the child safety seat

15 6. As can be seen from figures 1 and 2, the recess 5 extends most, but not all, of the way through ¹ the thickness of the mounting unit 1, such that there is only a thin layer of material 5a between the safety seat 6 and the vehicle seat 2 when the safety seat is mounted on the mounting unit

20 1. The walls of the recess 5 curve inwardly from the top of the mounting unit 1, so that the recess is smaller at the bottom than the top. Further, the walls substantially correspond in shape, with an engaging portion .7 of the safety seat 6, so that this portion of the safety seat 6 fits

25 within the aperture 5, where it can be fixed in place, for example by means of a socket and ball mechanism.

[0034] Figure 4 shows the mounting unit 1 viewed from above.

As can be seen from this view, the aperture 5 is symmetrical

30 about the line X-X. Thus, the safety seat 6 fits into the mounting unit in a forward facing manner as shown in figure

2, and a rearward facing manner, as shown in figure 3.

[0035] A sensing system 8 is integrated within the base of ^' 35 the vehicle seat. As described in more detail below, the

sensing system 8 is able to detect the presence of resonators 9L, 9R located in the safety seat 6 (see figure 5) , when the safety seat 6 is mounted in the mounting unit 1.

[0036] The resonators 9L and 9R are located at the bottom of the engaging portion 7 of the safety seat 6, such that the bottom surfaces thereof lie flush with the bottom of the safety seat 6.

[0037] Thus, when the safety seat 6 is mounted in the mounting unit 1, as shown in figures 2 and 3, the resonators 9L, 9R lie immediately adjacent, or in contact with, the thin layer of material 5a at the bottom of the aperture 5.

[0038] Figure 5 is a view of the safety seat 6, taken from below. As can be seen from this figure, the resonators 9R, 9L are located at equal distances either side of the centre line X-X which extends from the front to the rear of the engaging portion 7 of the child seat. However, the centres of the resonators 9L, 9R are offset towards the rear of the child seat from the centre line Y-Y, which extends from the left to the right of the engaging portion of the child seat. Thus, the resonators 9L, 9R are located in a different position with respect to the sensing system 8 when the safety seat is mounted in a forward facing manner as shown in figure 2, and when it is mounted in a rearward facing manner, as shown in figure 3.

[0039] When the safety seat 6 is mounted in the mounting unit 1, the sensing system 8 and the resonators 9L, 9R together form an inductively coupled system.

[0040] A suitable inductively coupled system is shown in figure 6. Here, the sensing system 9 comprises a

transmitting antenna 81 and a pair of receiving antennas 82L, 82R integrated within the base of the vehicle seat 2. The antennas are connected to a controller 83, also integrated within the vehicle seat. The transmitting ^" antenna 81 is connected to a power source (not shown) which causes a sinusoidal current (carrier signal) to flow therein when the system is switched on, thereby generating an alternating magnetic field around the transmitting antenna 81. When the resonators 9L, 9R are placed within this magnetic field, as they will be when- the safety seat 6 is mounted in the mounting unit 1 (as shown in figures 2 and 3) , the magnetic field inductively excites the resonators 9L, 9R ₁ . which modulate the phase shift of the carrier signal by periodical switching of the resonant frequency. The resonator generated phase shift is detected by the receiving antennas 82L, 82R and transmitted to the controller 83 for processing.

[0041] The phase shifted signals transmitted to the controller thus constitute an indication of the presence of the child safety seat, which enables the controller to control the various supplementary restraint systems present in the car in an appropriate manner. For example, air bag deployment for that seat can be prevented.

[0042] In addition, the controller can derive orientation information of the child seat by differentiating between the responses of the two resonators 9R, 9L. In particular, the controller can determine whether the child seat is in a forward facing orientation or a rearward facing orientation, and is able to control the various supplementary restraint systems (of the vehicle) accordingly. The controller is also able to determine whether the safety seat has been orientated incorrectly in the mounting unit, for example, if it has been arranged to face right or left in the car, instead of forwards or rearwards. The controller is thus able to raise

an alarm, or immobilize the vehicle, when the safety seat is incorrectly mounted.

[0043] In an alternative example, a pair of antennas/detectors are respectively arranged towards the front and the rear of the base of the vehicle seat. As discussed above, the centre of the resonators 9L, 9R are offset to the rear of the centre line Y-Y in figure 5. Thus, the rear-most detector detects a stronger response than the front-most detector when the child seat is mounted in a forward facing orientation, whilst the front-most detector detects a stronger response than the rear-most detector when the child seat is mounted in a rearward facing orientation. Both detectors are connected to a controller, which is able to determine the orientation of the child seat from the relative strengths of the detected responses. In this embodiment, the pair of resonators 9L, 9R could be replaced by a single resonator arranged centrally on the line X-X in figure 5, but offset to the rear of the centre line Y-Y in figure 5.

[0044] The above described presence and orientation detection system could be readily modified by a person skilled in the art to detect whether the safety seat has been orientated correctly in the mounting unit.

[0045] The present invention has been described with reference to the embodiment shown in figures 1 to 6. However, the skilled person will realize that alternative embodiments of the invention are also possible.

[0046] For example, the thin layer of material at the bottom of the aperture may be omitted. That is to say, an aperture

5 ' which extends all the way through the thickness of the mounting unit 1 may be formed in place of the recess, as

shown in figures 7 and 8. In this case, the resonator 8 will lie immediately adjacent, or in contact with, the base of the vehicle seat 2 when the safety seat is mounted in the mounting unit.

[0047] The recess 5 (aperture 7') may have a form other than a rectangle.

[0048] Further, the mounting unit may be attached to the vehicle seat 2 using the seat belt of the vehicle seat instead of the isofix latch system, as shown in figure 9.