Regulation 3.2 AUSTRALIA PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT ORIGINAL Name of Applicant: Britax Childcare Pty Ltd Actual Inventor: Wieslaw Maciejczyk Address for Service: Cl- MADDERNS, GPO Box 2752, Adelaide, South Australia, Australia Invention title: SEAT BELT GUIDE FOR CONVERTIBLE CHILD SEAT The following statement is a full description of this invention, including the best method of performing it known to us. 1 FIELD OF THE INVENTION The present invention relates to child safety seats or restraints for child passengers in vehicles. In a particular form the invention relates to a child safety seat adjustable to accommodate children of different ages and sizes. 5 PRIORITY This patent application claims priority from: - Australian Provisional Patent Application 2009904512, titled "SEAT BELT GUIDE FOR 10 CONVERTIBLE CHILD SEAT", and filed on 17 September 2009. The entire content of this application is hereby incorporated by reference. BACKGROUND 15 Young children cannot be safely restrained in a vehicle by a standard seat belt so specialised safety seats or child restraints have been developed to protect a child ranging in age from that of a newborn to that of a toddler, in the event of an accident. A number of child restraints or safety seats have been developed which are designed to accommodate this 20 wide range of ages with a single unit. Typically these seats can be configured in either the prone configuration suitable for a rearward facing installation, or the forward facing upright configuration. In this manner, a single safety seat can be used for both a baby (prone configuration) and a large toddler (forward facing configuration) thereby saving on unnecessary expense. 25 As well as the necessary pivoting and attachment arrangements which support the ability to configure the child restraint in either the prone or upright positions, it is clear that the dimensions of the actual seat which supports the child must be capable of adjustment to also accommodate the growth of the child. To provide this mode of adjustment, a number of arrangements have been developed, these including the use of a removable insert which sits within the seat and provides extra support to an infant, to adjustment 30 mechanisms, whereby the headrest portion of the seat forms a separate section to the seat body and is adjustable vertically to expand or contract the length of the back portion of the seat. Unfortunately, removable inserts as described above can be easily misplaced, and these do not effectively adjust the length of the seat. As for those seats that include adjustment arrangements and the like to adjust 35 the headrest, there are difficulties associated with providing a sufficient amount of shoulder harness strap for the full range of adjustment of the headrest, as excess strap can become twisted, tangled or foul workings of the seat. This difficulty is worsened where the seat is also a convertible one (i.e. adapted to 2 be configured in either the prone configuration suitable for a rearward facing installation or the forward facing upright configuration). It is an object of the present invention therefore to provide a child safety seat that ameliorates one or 5 more of the above described difficulties, or which at the least is a useful alternative to child safety seats of the prior art. Other objects and advantages of the present invention will become apparent from the following description, taken in connection with the accompanying drawings, wherein, by way of illustration and 10 example, an embodiment of the present invention is disclosed. SUMMARY OF THE INVENTION In a first aspect the present invention provides a child safety seat comprising a seat body with a base, a back portion, and a harness, where the harness is routed along a path of variable length on a rear side 15 of the back portion until routed through to a front side of the back portion, the path of variable length providing a harness reserve portion on the rear side of the back portion. In one form, a length of harness extending on the front side of the back portion of the seat is varied by varying the length of the path on the rear side of the child safety seat. 20 In one form, a length of harness extending on the front side of the back portion of the seat is lengthened by decreasing the length of the path on the rear side of the child safety seat. In one form, a length of harness extending on the front side of the back portion of the seat is shortened 25 by increasing the length of the path on the rear side of the child safety seat. In one form, the child safety seat further comprises an adjustable headrest, the position of which can be adjusted relative to the back portion. 30 In one form, the position at which the harness passes through the back portion of the body to the front side thereof is variable. In one form, the position at which the harness passes through the back portion of the body to the front side thereof follows the adjustable headrest. 35 3 In one form, the path includes one or more runs of harness extending substantially parallel to the back portion of the base. In one form, the path extends from an anchor point, to a first guide, and then from the first guide to the 5 position at which the harness passes through the back portion of the body to the front side thereof. In one form, the first guide is movable (i.e. its position is adjustable to vary the path length). In one form, this movement is parallel with the seat back. In an alternative, this movement is forward and backward, or a combination of up and down and forward and backward. 10 In one form, the path extends from the first guide to a second guide before passing through the back portion of the body to the front side thereof. In one form, the second guide travels is movable. In one form, the second guide travels with the headrest. 15 In one form, the first guide is located at or near the level at which the harness passes through to the front side of the back portion when the headrest is at its uppermost extent. In one form, the first guide is a member over which the harness can be passed and against which this can slide as the headrest is adjusted. 20 In one form, the harness comprises a single strap which diverges into a pair of parallel shoulder straps prior to being routed through to a front side of the back portion. In one form, each of the shoulder straps passes through an aperture in the back portion of the seat. 25 In one form, each of the shoulder straps passes through one of a pair of parallel slots extending up the back portion of the seat. In one form, a shutter element travels with the headrest so as to blank off a substantial portion of the slots extending up the back portion and define in conjunction with these a pair of substantially horizontal slots 30 through which one each of the shoulder straps passes. In one form, the headrest is adjustable between an upper and a lower extent of adjustment relative to the back portion. 35 In a further aspect the present invention provides a child safety seat comprising a seat body with a base, a back portion and an adjustable headrest, the position of which can be adjusted relative to the back portion, and a harness comprising a pair of shoulder straps, where a reserve portion of the harness is routed along 4 a path of variable length on a rear side of the back portion, and wherein a length of harness extending both on the front side of the back portion of the seat and in reserve, is varied by varying the position of the headrest relative to the back portion of the seat. 5 BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of this disclosure it will now be described with respect to an exemplary embodiment which shall be described herein with the assistance of drawings wherein: Figure 1 is a front perspective view of a child safety seat having an adjustable headrest set to its 10 lowermost position, where the dashed lines represent the position of the headrest and shoulder straps when the headrest is in its uppermost position; Figures 2 and 3 are rear perspective views of the child safety seat in Figure 1, where certain detail has been omitted in order to permit visibility of the harness, and where Figure 2 shows the headrest near its 15 uppermost position, and Figure 3 shows the headrest in a lower position; Figure 4 is a rear view of the child safety seat in Figure 1; Figure 5 is a side view of the child safety seat in Figure 1 illustrating the headrest in a position 20 approximately midway between its upper and lowermost extents; Figure 6 is a side view of the child safety seat in Figure 1 illustrating the headrest tilted forward to permit adjustment of the position of this; 25 Figure 7 is a side view of the child safety seat in Figure 1 illustrating the headrest at its uppermost extent; and Figure 8 is a side view of the child safety seat in Figure 1 illustrating the headrest at its lowermost extent. In the following description, like reference characters designate like or corresponding parts throughout 30 the several views of the drawings. TECHNICAL DESCRIPTION Referring now to Figure 1, where there is illustrated a child safety seat I for use with a seatbelt equipped vehicle seat, Such child safety seats are typically secured to the vehicle seat by the vehicle seat belts and 35 either of a tether strap or a specialized latching device, such as an Isofix latch, which is carried on the seating product and which interfaces with a complementary device carried by the vehicle seat. 5 The child safety I seat comprises a seat body 2 with a base portion 4 and a back portion 6, and an adjustable headrest 8, the position of which can be adjusted relative to the back portion 6. In the embodiment illustrated, the headrest 8 comprises a pair of optional side wings extending outwardly 5 and forward therefrom, which may be either deleted, or mounted to the back portion 6 of the seat body 2. The position of the headrest 8 is adjusted by grasping the upper edge of this, tilting it forward relative to the back portion 6 of the body 2, and then sliding the headrest 8 up or down as required (usually up as the child grows), [0 There is a seat belt harness 20 comprising a pair of shoulder straps 22 which converge into a single strap 24, where the end of this single strap 24 is adapted to be secured to an anchor point 26 toward the front and centre of the base portion 4 of the body 2 of the seat 1. A pair of vertically oriented parallel slots 25 extends through and up the back portion 6 of the seat body 2. [5 One each of the shoulder straps 22 passes through one of these slots. Each of the shoulder straps 22 then extends through a seat belt tongue 28 before terminating at spaced apart anchor points 30 on the body 2 of the seat 1. 20 Each of the seat belt tongues 28 are adapted to engage a seat belt buckle 32 that is secured to the base 4 by crotch straps 34 that terminate at spaced apart anchor points 36 on the body 2 of the seat 1. The harness 20 extends from its anchor point 26 and it is then routed along a path extending from the anchor point 26 to the position A at which the shoulder straps 24 pass through the back portion 6 of the 25 body 2 to a front side thereof. As the head rest 8 is moved up and down, so to does the position A move, so that this position A will remain about the height of the seat occupant's shoulders. 30 Referring now to Figure 5, where it can be seen that the path travelled by harness 20 extends from the anchor point 26, along the underside of the base 4 of the seat body 2, up a rear side of the back 6 of the seat body 2 to a first guide 50, from the first 50 guide to a second guide 60, and from the second guide through slots 25 to the front side of the back portion 6 of seat body 2. 35 In this exemplary embodiment the first guide 50 is a steel bar extending across and secured to the rear side of the back portion 6 of the body 2 of the seat 1. This first guide bar 50 is located at or about the level 6 of the position A when the headrest 8 is at its uppermost extent (see Figure 7), The shoulder straps 22 pass up and over this guide bar 50 and then extend to the second guide 60. The second guide 60 is also a steel guide bar, but this travels with the headrest 8, and so is always located 5 at or about the level of the position A. The shoulder straps 22 pass beneath this second guide 60 before passing through the slots 25 in the back portion 6 of the body 2 of the seat 1. Referring now to any one of Figures 4 through 8, the ends of this second guide bar 60 are adapted to be located in any one of a series of capture positions 54 notched into a pair of spaced apart tracks located on 10 and extending up the back side of the back portion 6 of the seat body 2, The second guide bar 60 is biased into engagement in one of the capture positions 54 by a biasing element such as a spring or elastic band (not shown). It should be emphasised that guides 50 and 60 may take forms other than steel bars. Guides 50 and 60 [5 may take the form of edges moulded into the relevant plastic components with which each is associated (the seat body in one case, and the headrest in the other). Grasping the upper edge of the headrest 8 and tilting this forward forces the second guide bar 60 out of its capture position 54 against the efforts of the biasing element, The headrest 8 can then be slid up and down 20 relative to the back portion 6 of the seat body 2. When the headrest 8 has been located in the desired position it can be released, where upon the biasing element forces the second guide bar 60 into the nearest capture position 54. A shutter element 70 slides against the front side of the back portion 6 and travels with the headrest 8. 25 The shutter element 70 blanks off a substantial portion of the parallel vertical slots 25 in the back portion 6, with the exception of a pair of horizontal slots through which one each of the shoulder straps 22 pass. In this way the shutter element 70, in conjunction with the second guide 60, precisely control the position A at which the shoulder straps 22 pass through the back portion 6 of the body 2 to the front side thereof. With reference to Figure 8, it can be seen that when the headrest 8 is at its lowermost extent then less of 30 the shoulder straps 22 are required on the front side of the back portion 6 of the seat body 2, and more of the shoulder straps 22 are retained in the guide means as reserve portions extending between guide bars 50 and 60. Referring now to Figure 5, where the headrest 8 is positioned approximately midway between its upper 35 and lowermost extents, so that more of the shoulder straps 22 are required on the front side of the back portion 6 of the seat body 2 than was required when the headrest 8 was at its lowermost extent. In follows then that the reserve portions extending between guide bars 50 and 60 are shorter. 7 Referring now to Figure 9, where it can be seen that when the headrest 8 is at its uppermost extent, more of shoulder straps 22 are required on the front side of the back portion 6 of the seat body 2 than was required when the headrest 8 was at its midway position. In follows then that the reserve portions 5 extending between guide bars 50 and 60 are very short. It is apparent then the above described arrangement advantageously facilitates a harness 20 having shoulder straps 22 of sufficient length to accommodate the headrest's 8 full range of adjustment. A further significant advantage is that the arrangement retains reserve portions of the shoulder straps 22 in such a 10 fashion that these cannot tangle or interfere with the workings of the seat 1. While the invention relates broadly to juvenile seating products, it is further described and illustrated in this application with reference to a child safety seat of the type generally described above, it being understood that the invention is not so limited. 15 It will be understood that the term "comprise" and any of its derivatives (e.g. comprises, comprising) as used in this specification is to be taken to be inclusive of features to which it refers, and is not meant to exclude the presence of any additional features unless otherwise stated or implied. Z0 The reference to any prior art in this specification is not, and should not be taken as, an acknowledgement of any form of suggestion that such prior art forms part of the common general knowledge. Although an illustrative embodiment of the present invention has been described in the foregoing detailed description, it will be understood that the invention is not limited to the embodiment disclosed, but is 25 capable of numerous rearrangements, modifications and substitutions without departing from the scope of the invention as set forth and defined by the following claims.
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