This invention relates to a push-chair which can be converted from a first mode in which it is adapted to move on wheels into a second mode in which the wheels are retracted and vice versa from the second mode to the first mode. It is particularly concerned with a child's buggy or stroller that can be easily and conveniently converted into a child's safety seat for use in a motor vehicle.

It has previously been proposed to provide a combined child's buggy and car safety seat and previous constructions are described in inter alia. US 5104134, US 4647054 and WO 92/18349.

The present invention aims to provide an improved seat of this general type having an improved retraction mechanism with a quick-release action between the open, buggy form and the retracted form.

The invention provides, therefore, a push-chair comprising a seat having a backrest and a seating portion, a frame to support the backrest and seating portion, wheels attached to the frame that in a first position extend below the frame into a ground- contacting position, the wheels being retractable upwardly into the frame into a second position, whereby in the second position the push-chair can be located on a seat in a motor vehicle and attached securely to the vehicle by suitable restraints, wherein the frame has a pair of spaced apart side members, a forward upper bracket, a rearward upper bracket and a lower bracket depending from or connected to each side member, each forward upper bracket pivotally carrying a forward upper strut, the distal end of which is pivotally connected to a first arm

carrying a front wheel, each rearward upper bracket pivotally carrying a rearward upper strut, the distal end of which is pivotally connected to a second arm carrying a rear wheel, the lower bracket pivotally carrying a front support strut, the distal end of which is pivotally connected to the first arm, and the lower bracket pivotally carrying a rear support strut, the distal end of which is pivotally connected to the second arm, whereby the wheels can be pivoted upwardly to rest within the frame in the second position and can be extended downwardly into the first position where each forward upper strut and its associated first arm are constrained by and supported on their respective front support strut and each rearward upper strut and its associated second arm are constrained by their respective rear support strut.

The invention also provides a frame to receive a seat, the frame having means to extend and retract wheels between first and second positions as described in the immediately preceding paragraph.

The forward upper bracket and rearward upper bracket are so called as each carries a forward upper strut and a rearward upper strut respectively. However, it is not essential that the forward bracket be forward of the rearward bracket with respect to the front and rear of the pushchair although this will be a normal configuration. They may be level with respect to front and rear or the rearward bracket may even be positioned forward of the forward bracket. They will usually be in the same horizontal plane with respect to the pushchair when on horizontal ground but this is not essential and one may be higher than the other. In another embodiment, they may be combined in an integral fixture.

In one embodiment each rearward upper strut and its associated second arm may also be supported on their respective rear support strut but this is not essential.

The pivotal connections between the struts and arms may be direct attachments between each strut and its respective arm or they may be via an intermediary, e.g. a joining block. Such a block, which may also give structural support in the open configuration, may be, for example, of moulded plastics material, e.g. nylon.

The frame preferably has one or more cross-members to give it required strength and rigidity and will have upwardly extending rear frame members to support the backrest portion of the seat. The rear frame members may have extensible handles that can be extended in a manner known per se for use in pushing the push-chair and retracted when the push-chair is to be converted into its car safety seat form.

The quick release mechanism can conveniently be a cross-bar pivotally attached at each end between the two second arms, i.e. the arms associated with the rear wheels. The cross-bar may be attached to the arms directly or via a bracket or flange at each of its ends. Extending forwardly from adjacent each end of the cross-bar or from its associated means of attachment to the second arms is a strut pivotally connected at its forward end to the first arm carrying a front wheel. Retraction and opening of the front and rear wheels is thereby effected simultaneously by grasping the cross-bar and moving it upwardly or downwardly as appropriate. Each strut may be attached at or towards the end of the crossbar but it will be appreciated that the pair of struts must be spaced for the centre point of the cross-bar.

In a further preferred embodiment the support struts, particularly the front support struts, can be of a generally 'Z'-shape whereby an increased gap can be provided underneath the strut so that the wheels can be raised to a higher level within the frame than would otherwise have been possible.

Specific embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which:

Figure 1 is a perspective view of a pushchair of the invention in retracted form for positioning on a seat in a motor vehicle;

Figure 2 is a perspective view of a frame of the invention minus its backrest support portion;

Figure 3 is a composite diagrammatic illustration of the opening and retracting mechanism to be attached to the frame of Figure 2 and one half as shown in Figure 3a is in the open position and the other half is shown in Figure 3b in the retracted position;

Figure 4 shows a detail of the front wheel retraction mechanism in an alternative embodiment to that of Figure 3, in open configuration;

Figure 5 is a rear view of a frame of the invention showing the quick-release cross bar;

Figure 6 is a front perspective view of an alternative pushchair of the invention in open configuration;

Figure 7 is a diagrammatic illustration of one half of the opening and retracting mechanism of the chair of Figure 6 in open configuration;

Figure 8 shows the mechanism of Figure 7 in closed configuration; and

Figure 9 is a rear view of the pushchair of Figure 6 in closed configuration.

In Figure 1 is shown a push-chair 10 having a seat 12 comprising a backrest portion 13 and a seating portion 14. The seat 12 sits on a frame 16 having a lower frame portion 17 and an upwardly extending rear member 18. A pushing handle 20 is shown in its lowermost retracted position on rear frame member 18.

The push-chair has front wheels 50, each of which as shown is a double wheel and rear wheels 60, each of which again is a double wheel. The wheels are in the retracted position within the lower frame 17 so that the retracted push-chair can sit on the rear seat of a motor car to which it is to be attached by seat belt 28.

In Figure 2 is shown the lower portion 17 of the frame 16, the upwardly extending rear members 18 having been omitted for clarity.

Frame portion 17 has a pair of spaced-apart side members 30,31 joined by a reinforcing cross-member 32 and two spaced downwardly extending front members 34,35 which are joined by a foot cross-member 36.

(All the frame members can conveniently be of tubular metal).

Cross-member 32 carries, adjacent side members 30,31 , a forward upper bracket 38, and a rearward upper bracket 40 is carried by struts 41 and 42 extending inwardly and rearwardly from the side members 30,31 and the cross-member 32 respectively.

A lower bracket 44 is carried by a downward extension 30a,31a of the side members.

Figure 3 shows the opening/retraction mechanism of the push-chair one half being in extended form and the other half in retracted form.

Each front wheel 50 is rateably attached to one end of hook-shaped arm 52 and arm 52 has a pivotal attachment 54 at its other end to one end of a forward upper stmt 56. The other end of stmt 56 has a pivotal attachment 58 to forward upper bracket 38 (not shown) of the frame. Each rear wheel 60 is rotably attached to one end of an arm 62 and arm 62 has a pivotal attachment 64 at its other end to one end of a rearward upper stmt 66. The other end of stmt 66 has a pivotal attachment 68 to rearward upper bracket 40 (not shown) of the frame.

A stmt 70 pivotally connects between each pair of arms 52 and 62. The pivotal connection 72 at one end of stmt 70 is made centrally of arm 52 and at its other end the pivotal connection is made at the same connection 64 between arm 62 and stmt 66.

Lower bracket 44 (not shown) in Figure 3 has a pivotal connection 74 to one end of front support stmt 76 and to one end of rear support strut 78. The other end of front support stmt 76 is pivotally connected at 80 to arm 52 between pivotal connection 72 of stmt 70 and pivotal connection 54 of stmt 56. The other end of rear support stmt 78 is pivotally connected at 82 on arm 62 between the wheel and pivotal connection 64 to stmt 66.

Rearward and upward pivotal movement of stmts 70 synchronously retracts the wheels to the position shown in Figures 1 and 3b. Downward and forward movement of stmts 70 extends the wheels to the open position.

Conveniently (see Figure 5) a cross-bar 90 extends between the rearmost ends of the stmt 70 adjacent pivots 64. The cross-bar can be grasped from the rear of the push-chair to open or close the chair as required. Cross-bar 90 may be locked in the open position and in the closed position by any convenient means. For example, quick-releasing locking means of conventional type may be provided on rear support stmt 78 and arm 62 or on stmt 78 and stmt 66 to lock the mechanism in the open position. Similarly, locking means may be provided between cross-bar 90 and the upwardly extending rear frame portion to lock the mechanism in the retracted position.

As shown in Figure 3a, the opening movement of arm 52 and upper stmt 56 is stopped when it comes into contact with front support stmt 76 and load transmitted through arm 52 and stmt 56 is carried by stmt 76. Similarly the opening movement of arm 62 and upper strut 66 is stopped when it comes into contact with rear support stmt 78 and load transmitted through arm 62 and stmt 66 is carried by stmt 78.

Figure 4 shows a modified form of front support stmt. The modified front support stmt 100 is of generally Z-shape having end portions 100a and 100c and a central portion 100b. It is attached, as before, at one end of section 100a by pivotal connection 80 to arm 52 and at its other end by pivotal connection 74 to lower bracket 44 (not shown).

In the extended, open position the pivoted end 54 of forward upper stmt 56 bears on support portion 100a of stmt 100 adjacent central portion 100b and stmt 56 lies substantially parallel to central section 100b of stmt 100. Space 102 defined by portions 100b and 100c of stmt 100 represents additional room for a wheel to be retracted further into the frame.

The angles between portions 100a, 100b, 100c may be varied according to the required dimensions of the push-chair.

A further embodiment of the invention is shown in Figures 6 to 9.

In this embodiment, as is described in more detail below, the pivotal connections between the various stmts and arms are made via intermediate blocks of plastics material, i.e. each strut or arm is pivotally connected to a block instead.

The pushchair 110 (Figure 6) has front wheels 150 and rear wheels 160, each of which has a mudguard 123, 125 respectively. The mudguards can be arranged to rotate so as to be positioned beneath wheels in the retracted position so as to provide some protection against wet and dirt when the retracted chair is positioned on a car seat.

The pushchair 110 has a frame 116 having a lower frame member 117 and an upwardly extending rear member 118 to which is attached a pushing handle 120. The pushchair has a seat 112 having a backrest portion 113 and a seating portion 114. Guides 126, 128 are provided on the frame to receive seat belts of the rear seat, say, of a car on which the retracted pushchair is to be secured.

Frame portion 117 has a pair of spaced apart side members 130, only one of which can be seen, joined by a generally U-shaped reinforcing cross-member 132, which in this embodiment passes underneath the frame, and two spaced, downwardly- extending front members 134, 135 which are joined by a foot cross-member 136.

Forward and rearward upper brackets 138 and 140 respectively are mounted on the inside of each side member 130. A lower bracket 144 is mounted via a block 144a on the inside of each arm 132a of the U-shaped cross-member 132.

In Figures 7 and 8, one half only of the mechanism is shown, the other half being identical.

Each front wheel 150 is rotatedly attached to one end of an arm 152 the upper end of which is fixed in a correspondingly shaped blind bore 153A in a block 153. Pivotally attached at pivot 154 to the other end of block 153 is one end of a forward upper stmt 156. The other end of stmt 156 has a pivotal attachment 158 to forward upper bracket 138 (not shown) of the frame. By this means arm 152 is indirectly pivotally connected to forward upper strut 156.

A U-shaped cross member 155 (see Figure 6) has the end of each arm of the U embedded in one of the blocks 153.

Each rear wheel 160 is rotatably attached to one end of an arm 162. Arm 162 passes through a corresponding bore 163A through a block 163 and terminates beyond the block 163. A cross-member 190 joins the free end of arms 162 (see Figure 9). Rearward upper strut 166 has pivotal attachment 165 at one end to block 163 and a pivotal attachment 168 at its other end to rearward upper bracket 140 (not shown) of the frame. By this means arm 162 is indirectly pivotally connected to rearward upper strut 166.

A stmt 170 pivotally connects between each pair of the front and rear wheels 150 and 160. The pivotal connection 172 at one end of each stmt 170 is made to a block 171 attached to cross-member 155. The pivotal connection not shown at the

other end of each stmt 170 is made to a block 181 on cross-member 190 (see Figure 9).

Lower bracket 144 (not shown in Figures 7 and 8) has a pivotal connection 174 to one end of front support stmt 176 which is of generally Z-shape, and to one end of rear support stmt 178. The other end of support stmt 176 is pivotally connected at 180 to block 153 whereby it is indirectly pivotally connected to arm 152. The other end of rear support stmt 178 is pivotally connected at 182 to block 163 whereby it is indirectly pivotally connected to arm 162.

In the open configuration each forward upper stmt 156 is supported on the central region 176a of support stmt 176.

Rearward and upward movement of stmts 70 synchronously retracts the wheels to the position shown in Figure 8. Downward and forward movement of stmts 170 extends the wheels to the open position of Figure 7. Both of these movements are conveniently achieved by grasping and moving cross-member 190.

The invention is not limited to the above-described embodiments. For example, the frame of the push-chair may be held in placed in the retracted configuration on a car seat by a conventional seat belt. This attachment may be by a lap and diagonal seat belt, lap seat belt or, alternatively a fixing kit may be used. Moreover, the backrest portion and seating portion of the seat may be securely attached to anchorage points in the car by any conventional attachment means for a child's safety seat. Any convenient catch member may be provided to retain the pushchair in the closed and in the open positions. A foldable footrest may be attached to the foot cross member. A fairing may be provided around the sides of the frame.

As indicated the wheels of the push-chair may be provided with mudguards and these may be rotatable to lie underneath the wheels in the retracted position to keep the car seat clean. Alternatively, other means, e.g. a mat, may be used for that purpose.