US20080277984A1

US20080277984A1 - Child Safety Seat

Info

Publication number: US20080277984A1
Application number: US11/914,851
Authority: US
Inventors: David Shaun Carine
Original assignee: Britax Childcare Ltd
Current assignee: Britax Childcare Ltd
Priority date: 2005-05-20
Filing date: 2006-05-22
Publication date: 2008-11-13
Also published as: JP2008540249A; GB0510313D0; CA2609011A1; CN101247972A; WO2006123169A1; EP1890907A1

Abstract

The present invention concerns a child safety seat (1) for use with a vehicle seat. The child safety seat comprises a child seat body having: —a child support portion (2), and a base member (7), a link (11) projecting from the child seat body, and a releasable connector (12) provided on the link for engagement with an anchorage unit associated with the vehicle seat. The link is attached directly to the child seat body by a pivot connection (14) that permits angular movement of the child seat body relative to the link about an axis, a foot prop (24) being provided at the front of the child seat body.

Description

The present invention relates to a child safety seat, particularly though not exclusively for use in vehicles such as cars.
Original child safety seats were secured in cars via anchorages fixed to the car. Insofar as this involved after-market drillings of car bodies, this was unsatisfactory. The system that became and remains widely used is for car child safety seats to be secured by adult seat belts. This has limitations, primarily because such adult belts have long lateral runs which due to trigonometrical effects can allow significant forwards movement of the child safety seat for small extensions of the adult belt. In this connection, adult belt systems are designed to restrain adults not child safety seats.
A system finding increasing use is the so-called Isofix system, in which the child seat is attached via links or latches to loop mountings fixed in the car. This system addresses child seat movement resulting from extension of the seat attachment means.
However, the Isofix system relies on two points (the loop mountings) which are fixed in the car (even although these are possibly adjustable in the car with adult seat adjustment). The loop mountings define an axis transverse of the car, and as such a child seat mounted thereon has a tendency to rotate about this axis (“the Isofix Axis”).
Mechanisms for dealing with such rotation exist. One such mechanism involves the attachment use of top tethers, and these have been widely used in certain countries, even prior to use of the Isofix system. A top tether is a tether from the top of the child safety seat to a rigid point in the car body. Provision of such a point adds cost to cars and as such is not ideal.
Foot props also are known for resisting rotation of child safety car seats about the Isofix Axis. A foot prop is used in one of the present applicant's products, namely a base for a rear facing Group 0+infant carrier. The base is attached by Isofix latches at its rear end. Its front end extends off the adult seat and the foot prop supports the base against diving down in an accident due to the centre of gravity of the infant being above the Isofix Axis. This is described in our UK Patent Application No. 0410303.2.
Other mechanisms are known for controlling rather than preventing rotation of the child seat. For instance the present applicant's “Isofix Pivoting Link” European Patent Application No. 00308653.5 describes a child safety seat comprising a child seat structure having a base support surface for resting on a vehicle seat cushion, a back support surface for abutting against the seat back of said vehicle seat and a seating surface for a child occupant, together with a rigid link projecting from the child seat structure. A releasable latch connector is mounted on the rigid link for engagement with a standard anchorage unit such as a loop mounting associated with the vehicle seat. The rigid link is attached directly to the child seat structure solely by a pivot connection that permits angular movement of the child seat structure relative to the rigid link about an axis located above the base support surface. This arrangement operates to control the movement of the child seat so that forward and rotational movement thereof is translated at least in part into downward movement.
Hence whilst the foot prop arrangement simply operates to resist downward diving of the child seat base, the pivoting link arrangement acts to control and translate the forward and rotational movement. These arrangements are as such wholly separate mechanisms for dealing with undesirable seat motion.
On their own, each of these arrangements alleviates undesirable rotational movement relating to the seat, albeit in different ways. However, with a foot prop arrangement, the foot prop in essence provides a solid stop resisting diving of the seat base. With the pivoting link arrangement, the emphasis is to control the rear of the child seat and thereby translate forward movement into downwards movement.
Each arrangement has its own benefits, but there are also potential disadvantages from one to the other. With the foot prop arrangement, the prop acts as a solid stop, providing no, or very limited translation or dissipation of forward to downward energy in the system. With the pivoting link arrangement, the front of the seat base remains free, such that its movement at the front, though controlled from the rear, is open to deviation.
The object of the present invention is to provide an improved child seat alleviating the problems of existing arrangements.
According to the present invention there is provided a child safety seat for use with a vehicle seat, the child safety seat comprising:—a child seat body having:—a child support portion, and a base member, a link projecting from the child seat body, and a releasable connector provided on the link for engagement with an anchorage unit associated with the vehicle seat, wherein the link is attached directly to the child seat body by a pivot connection that permits angular movement of the child seat body relative to the link about an axis, a foot prop being provided at the front of the child seat body.
As such, the child safety seat benefits from both a pivoting link arrangement as well as a foot prop. Combining these two features is somewhat counterintuitive since one would assume that the use of one in combination with the other would adversely affect their respective operations.
However, a combination of the pivoting link and a foot prop (“the Combination”) has shown unexpected and surprising improvements in performance in comparison with a control experiment using an arrangement (such as described in our Patent Application No. 0410303.2, except with a forwards facing child seat).
In the control experiment, whilst one might expect no forward rotation of the child safety seat, being connected to the Isofix Axis and propped at the front, the top of the child safety seat does in fact move forwards from the back of the adult seat in a simulated accident. This is attributed to flexibility of the component parts of the child safety seat and the foot prop.
In the experiment on the Combination, the top of the back of the child safety seat does not move appreciably away from the top of the back of the adult seat. This in itself is surprising, since the Isofix pivoting link is so arranged as to allow the bottom of the child safety seat to move slightly forwards with respect to the Isofix axis.
Preferably, the child support portion has back and base portions provided substantially in an L-configuration, the links being pivotally connected to the child seat body above an underside of the base member and in the region of the root of the L. Conveniently, the links extend rearwards of the child seat body.
The pivot point of the link with the child seat body is preferably closer to the junction of the back portion and the base portion than respectively a top end of the back portion and a front end of the base portion.
The child support portion may be provided as a shell or carapace as per the current normal construction of child safety seats. However, the invention is not intended to be restricted to this construction.
Whilst it can be envisaged that the link may be pivoted directly on the child support portion of the seat body, with the lower portion thereof forming the base member, the child safety seat can alternatively comprise a separate base member on which the child support portion is mountable. This may enable the child support portion to be reclined on the base member, for allowing the child to sleep on long journeys or for the child support portion to be removed altogether.
Further, to assist in attachment of the child safety seat with as little possibility to rebound as possible, the link or preferably its pivot may be adjustable to urge the back portion against the vehicle seat back.
A metal framework is preferably provided, at least at the front of the child safety seat for the foot prop, which conveniently is formed of metal. Nevertheless, other possibilities such as a polymer foot prop and a polymer supporting structure for it can be envisaged.
In order to enable ready connection of the link to the mounting loops or points, involving rearwards movement, the links are preferably partially L shaped.
The links are moreover preferably rigid and provide a rigid link between the mounting loops and the pivot axis on the child safety seat.
According to a further aspect of the present invention there is provided a child safety seat adapted to be attached at an adult seat having rigid attachment points associated with it and installed in a vehicle having a floor, the child seat comprising: a child seat body, having: a child support portion having substantially a L-configuration; and an underside; a link pivotally connected to the child seat body above the underside and in the region of the root of the L, the link having: latches for attachment of the child safety seat to the rigid attachment points, the latches extending rearwards of the child safety seat; and a foot prop provided at the front of the seat for extension below the level of the underside and for abutment with the vehicle floor.
According to a yet further aspect of the present invention there is provided a child safety seat system for use with a vehicle seat, the child safety seat system comprising:—a base member for installation on the vehicle seat, and a child support member for releasable attachment to the base member, the base member further comprising:—a link projecting therefrom, and a connector provided on the link for engagement with an anchorage unit associated with the vehicle seat, wherein the link is attached directly to the base member by a pivot connection that permits angular movement of the base member relative to the link, and wherein a foot prop is further provided at the front of the base member.

A specific example of the present invention will now be described by way of example and with reference to the accompanying drawings, in which:

FIG. 1 shows a perspective view of a child safety seat of the present invention;

FIG. 2 shows a side view of the seat of FIG. 1 in a first position; and

FIG. 3 shows a side view of the seat of FIG. 1 in a second position.

Referring to FIG. 1, a child seat 1 has a child support portion 2, in the form of an injection moulded shell 3 and is upholstered with a suitable cover 4. The child support portion 2 has a back portion 5 and a base portion 6, which are arranged in a substantially L-configuration. The child support portion is mounted on a base member 7.
The child support portion is provided with a harness 8 for strapping in a child and is reclinable on the base member via at an arcuate interface 9.
An Isofix Pivoting Link 11 is provided to connect the child safety seat 1 to Isofix points P in an adult vehicle seat A. The link has latches 12—one each side—to the points P and a pivot axis 14 to the base 7. The pivot axis can be adjusted in the base member, to enable the seat to be pushed back for abutment of a back surface 15 of the back portion 5 against the back B of the adult seat. The underside of the child seat, in effect the underside 16 of the base member presses against the seat cushion S of the adult seat. This pressure can be provided by the interaction of the two seat backs and the adjustment mechanism.
The base member is provided with a steel tubular frame 21, arranged as a U, with two limbs 22 extending from front to back, and an interconnecting member 23 extending in front of the base member at a position spaced in front of the front F of the adult seat cushion S. A foot prop 24 is pivotally connected to the interconnection 23. Suitable interconnection means are provided, such as stops/catches in detents (not shown), for holding the foot prop in a non-use position back underneath the underside 16, and a deployed position in which it extends down to a vehicle floor F. It is telescopically adjustable 25 to provide firm contact in use of a foot 26 with the floor.
In use, a child C is strapped into the child safety seat, with a centre of gravity (C of G) well above the base portion of the child support portion 6 and the pivot axis 14. In an accident, the child is thrown forward against the harness 8, which applies a forwards force to the child seat. This force acts at the pivot 14 and creates a moment about the Isofix axis at the Isofix points P. The result is that the link 11 rotates downwards. The rear end of the base member 7 and the entire child seat moves down. At the same time, reaction from the adult seat cushion S and from the foot prop 24, which is at an appreciable lever arm with respect to the pivot axis 14 and the Isofix Axis, resist downwards movement of the front of the seat. However the rear of the seat does move down. The result is the paradoxical situation that a forwards acceleration of the child results in the top of the child seat being held back against the adult seat back.
This is particularly beneficial, because the upper fastening of the harness and in particular the shoulder pads which contribute to the restraint of the child, become tensioned to full extent early in the accident, restraining the child without free movement allowing the child to move forwards and then, be sharply restrained. In turn this results in peak accelerations of the child's head being contained.
In terms of the comparative tests mentioned in the preamble above, the seat of the invention showed a 20 g improvement in peak head acceleration and a 40 mm improvement in peak head displacement.

Claims

1. A child safety seat for installation on a vehicle seat, the child safety seat comprising:—

a child seat body having:—

a child support portion, and

a base member,

a link projecting from the child seat body, and

a releasable connector provided on the link for engagement with an anchorage unit associated with the vehicle seat,

wherein when in use, with the child safety seat installed the link is attached directly to the child seat body by a pivot connection that permits angular movement of the child seat body relative to the link about an axis, a foot prop being provided at the front of the child seat body.

2. A child safety seat according to claim 1, wherein the child support portion has a back portion and a base portion provided substantially in an L-configuration, the link being pivotally connected to the child seat body above an underside of the base member and in the region of the root of the L.

3. A child seat according to claim 1, wherein the link extends rearwards of the child seat body.

4. A child seat according to claim 1, wherein the pivot point of the link with the child seat body is closer to the junction of the back portion and the base portion than respectively a top end of the back portion and a front end of the base portion.

5. A child seat according to claim 1, wherein the child support portion is provided on a separate base member.

6. A child seat according to claim 5, wherein the child support portion is adjustably reclinable on the base member.

7. A child seat according to claim 5, wherein the link is provided directly to the base member.

8. A child seat according to claim 1, wherein the link and/or its pivot is adjustable for urging the back portion against the vehicle seat back.

9. A child seat according to claim 1, wherein metal framework is preferably provided, at least at the front of the child seat body for the foot prop.

10. A child seat according to claim 1, wherein two or more rigid links are provided.

11. A child safety seat system for installation on a vehicle seat, the child seat system comprising:

a base member for installation on the vehicle seat, and a child support member for releasable attachment to the base member,

the base member further comprising:

a link projecting therefrom, and

a connector provided on the link for engagement with an anchorage unit associated with the vehicle seat,

wherein when in use, with the child safety seat system installed the link is attached directly to the base member by a pivot connection that permits angular movement of the base member relative to the link, and wherein a foot prop is further provided at the front of the base member.

12. (canceled)

13. A child safety seat system according to claim 12, wherein the child support member has a back portion and a base portion provided substantially in an L-configuration.

14. (canceled)

15. (canceled)