WO2003074342A1

WO2003074342A1 - Collapsible buggy

Info

Publication number: WO2003074342A1
Application number: PCT/NL2003/000159
Authority: WO
Inventors: Walter Grim
Original assignee: Wf International Holding B.V.
Priority date: 2002-03-01
Filing date: 2003-03-03
Publication date: 2003-09-12
Also published as: NL1020099C2; AU2003218829A1

Abstract

The invention relates to a collapsible buggy, provided with at least a front wheel (4), two rear wheels (5) and a frame (3), wherein each (rear) wheel (5) is carried by a mounting bracket (22) which is pivotally connected to the frame through pivot means (23) wherein the pivot means of each mounting bracket include an axis (M) which in normal operating condition includes an angle with the longitudinal direction of the axes of the (rear) wheels, wherein the (rear) wheels together with the mounting brackets are pivotable relative to the frame and each other towards a collapsed condition.

Description

Title: Collapsible buggy

The invention relates to a buggy, more particular a collapsible buggy.

Classical children's strollers are known, comprising a chassis with four relative large wheels and a cradle, usually detachably mounted, to accommodate a reclined child.

In addition, buggies are known, which enable a child to be transported in an upright or reclined seating position, and to that end comprise a chassis mounted with a child seat, which may or may not be detachable. Compared to the classical stroller, the wheels of the buggy are smaller and often of double construction.

Yet another known category is formed by the three-wheeled buggies, which comprise a chassis with three relative large wheels, one in the front and two at the rear side, and a detachable seat. The seat can be replaced by a cradle, providing a new type of buggy. Advantages of this last category are ease of handling thanks to the three-wheeled construction and a sportive look, common to this type of buggies.

A latest trend features a four-wheeled buggy, based on the sportive appearance of a three-wheeled buggy. With these four-wheeled buggies too, the seat can be replaced by a cradle. Occasionally, the larger wheels are replaced by two smaller wheels each, which on top of that often may be swingable.

A disadvantage of known buggies in general is their considerable size in collapsed condition, for storing or transporting of the buggy, for instance in a car. After bringing these known buggies into a collapsed configuration the wheels thereof may considerably extend side ways rod ways and frequently need to be disassembled in order to fold the buggy as compact as possible. It is therefore an object of the invention to provide a buggy of the above -de scribed type, which can be collapsed into a very compact unit, so that it can be stored in a small space (such as a closet, automobile trunk, etcetera), without having to disassemble one or each wheel, but just by folding the buggy in a special way.

To that end, a buggy according to the invention is characterised by the features of claim 1. By connecting each rear and/or front wheel pivotally to the frame around a pivot axis which in unfolded condition includes an angle with the axis of the respective rear and/or front wheels, the advantage is achieved that upon bringing the buggy into a collapsed condition through pivoting of the wheels towards the frame, the rear wheels (in case of a three wheeled buggy) will move towards the front wheels (or the front wheels will move towards the rear wheels in case of a four wheeled buggy), as well as towards each other, thus reducing both the length and width of the wheel base in extended condition. Hence, a collapsible buggy can be conceived having a relatively broad wheelbase in extended condition (measured in the direction of the rotation axes of the rear wheels) with matching stable road holding, yet having a very narrow wheelbase and hence a compact width in collapsed condition. In a preferred embodiment, a collapsible buggy according to the invention is characterised by the features of claim 3.

By configuring the frame in such way that in collapsed condition the front and rear wheels can extend at least partially next to each other, preferably flanked by one of more frame portions, a very compact sized unit can be obtained. Furthermore, the frame may advantageously serve to keep the wheels together and protect them from being exposed to potential harmful shocks, which could cause the wheels for example to become wobbled or to get a flat tire.

In a further preferred embodiment a collapsible buggy according to the invention is characterised by the features of claim 4. By applying a rod assembly, the (rear) wheels can be kept in substantial parallel orientation with respect to each other during collapsing the buggy. Thus, the rod assembly may contribute in reducing the overall width of the collapsed buggy (measured in the direction of the rear wheel axes), since it will be appreciated that the width of the buggy will be minimum with the (rear) wheels extending substantially parallel to one another.

In a highly advantageous embodiment, a collapsible buggy according to the invention is characterised by the features of claim 5.

Thanks to such coupling, collapsing and unfolding of the buggy is greatly facilitated. Preferably, the mounting brackets are coupled to the frame in such way, that by folding an upper half of the frame towards or away from a lower half of the frame, all other collapsible parts of the buggy, in particular the mounting brackets with the rear wheels, ^"are automatically brought in a collapsed or unfolded condition as well. To that end the coupling means can for instance be configured as rods, extending between the mounting brackets and an upper half of the frame of the buggy which is pivotally connected to a lower half of the frame, according to the features of claim 13. Thanks to such vertical orientation, the rods, during use, will be mainly subjected to axial loads (tensile and pressure) instead of bending loads (lateral forces) against which the rods have less resistance. Operation of the buggy between an unfolded and folded condition can even be further facilitated by providing the buggy with external drive means, such as for instance a pneumatic, hydraulic or mechanic spring, for supporting or performing at least part of the folding or unfolding operations. In further elaboration a collapsible buggy according to the invention is characterised by the features of claim 8.

By making the mounting brackets and the front fork of substantial equal length, minimum height can be achieved in collapsed condition, without the at least one front wheel or the rear wheels having to be disassembled or pivoted around a further pivot axis. By furthermore selecting the orientation of the pivot axles of the mounting brackets according to the features of claim 9, a buggy can be conceived having a relatively broad, and therefore stable wheel base in unfolded condition and yet having a relatively small wheel base in collapsed condition, whereby the maximum width is determined by the width of the frame part mounting the seat, rather than the wheel carrying part of the frame. Moreover, by providing the buggy with rear wheels suspended on two independent mounting brackets, space becomes available between these rear wheels, which may be used as walking space, or used for additional storing capacity, by providing a net or basket. Furthermore, independent rotational movement of the mounting brackets may further enhance the stability and comfort of the buggy, when negotiating potholes or bumps in the road.

In further elaboration, the buggy according to the invention may be characterised by the features of claim 10. By placing the mounting brackets and front fork, seen in side view, under a relatively large angle, the length of the wheel base in unfolded condition may be increased. Moreover, the centre of gravity will be situated relatively low to the ground and within the footprint of the wheels. All these effects enhance the stability of the buggy and prevent it from tipping over too easily.

In a further advantageous embodiment, a handle for pushing the buggy may be pivotally connected to the frame, according to the features of claim 14. Thanks to such configuration, the height of the handle, as measured from the ground, may be adapted to the height of a user, by simply varying the angle between the handle and the frame.

In an even further advantageous embodiment a buggy according to the invention is characterised by the features of claim 15.

By making the upper and lower frame part of substantial equal length, a buggy can be configured having a frame with a substantial length and height in unfolded condition, offering convenience of use when pushing the buggy, and yet having minimal height in folded condition.

In further elaboration, the frame of the buggy is configured such that a child support may be mounted between members of said frame, preferably detachably, for instance by press buttons or barbed tape, or a combination thereof. This allows various types of child supports, such as a seat or a cradle, to be interchanged, allowing versatile use. In a further preferred embodiment, the child supports may be of flexible, foldable design, so that they do not need to be removed before collapsing the buggy, increasing the convenience of use even further.

These and further advantageous embodiments of the invention are set forth in the dependent claims.

DESCRIPTION OF THE DRAWINGS Herein after the invention will be explained further, with reference to but not limited to the embodiments as presented in the accompanying drawings, wherein:

FIGs. 1-5 show a buggy according to the invention, in unfolded condition, from different points of view; FIGs. 6-8 show the buggy of FIGs. 1-5 in collapsed condition, from different points of view;

FIGs. 9-11 show the rear wheels of the buggy according to the invention in extended, partially collapsed and completely collapsed condition respectively; FIGs. 12, 13 show a buggy according to the invention, in unfolded condition, provided with a seat; and

FIGs. 14, 15 show a buggy according to the invention, in unfolded condition, provided with a cradle.

In this description, identical or corresponding parts have identical or corresponding reference numerals. All combinations of parts of the embodiments shown and described in this description are explicitly understood to fall within the scope of the invention as outlined by the claims and are explicitly understood to be incorporated within this description.

FIGs. 1-5 show a buggy 1 according to the present invention, in unfolded condition, comprising a frame 3, carried by a front wheel 4 and two rear wheels 5. The frame 3 comprises an upper frame part 6 and a lower frame part 7, which are pivotally connected by means of central pivot means 8, allowing the upper frame part 6 to be pivoted towards the lower frame part 7 around a central pivot axis C, as indicated by arrow P in FIG. 1, wherein axis C extends substantially parallel to the axes of rotation B of the rear wheels 5. Locking means are provided (not shown) to lock the central pivot means 8 against pivotal movement, at least in the unfolded condition shown in FIGs. 1- 5, in which condition the upper and lower frame parts 6, 7 extend substantially in one plane, which inclines backward, seen in the main direction of travel of the buggy 1.

The upper and the lower frame part 6, 7 each comprise two frame members 11, 12; 13, 14, which extend substantially parallel to one another, at a distance WF. The upper frame members 11, 12 are joined together near their upper end 15 by means of a substantially C-shaped handle 17. This handle 17 is preferably pivotally connected to the upper frame part 6 by means of a hinge 18, allowing a user to adjust angle δ between said handle 17 and the upper frame part 6 (see FIG. 3) and consequently the height H of the handle 17 to the ground, according to his or her personal preferences.

The lower frame members 13, 14 are interconnected by a cross bar 20, which extends substantially parallel to and at some distance below the central pivot axis C. The lower ends 16 of the lower frame members 13, 14, extending beyond said cross bar 20, are bent towards each other so as to form a bottle-shaped front fork 19, in which the front wheel 4 is rotatably mounted around axis A Two mounting brackets 22 are pivotally connected to the back of the cross bar 20, near the middle thereof, by pivot means 23. The pivot means 23 are arranged in such way that with the buggy 1 in unfolded condition, the pivot axis M of each mounting bracket 22 includes an angle α with the axis of rotation B of the rear wheels 5 (as best seen in FIG. 5) as well as an angle γ with the horizontal plane (as best seen in FIG. 4). In extended condition, the mounting brackets 22 slope downwards from the cross bar 20, to include an angle β with the front fork 19 (see FIG. 3) and furthermore slope sideways so that the rear wheels 5, which are rotatably mounted near the ends of the mounting brackets 22 around axis of rotation B, extend beyond the frame members 11, 12 (as best seen in FIG. 5). In other words, the width W of the wheelbase is larger than the width WF between the frame members 11, 12; 13, 14 (see FIG. 4). The brackets 22 can be of single or double construction, as illustrated in the Figures. The mounting brackets 22 are furthermore coupled to the upper frame part 6 by means of two rods 24, which with one end are pivotally connected to an upper frame member 11, 12, near the central pivot means 8 and with another end are pivotally connected to the mounting bracket 22, near the rear wheel 5. The points of connection of the rods 24 are preferably chosen in such way that the rods 24, at least in unfolded condition, extend substantially vertical, as best seen in FIGs. 3 and 4. This offers the advantage that in use, while transferring external forces acting on the frame to the wheels and vice versa, the rods 24 will be mainly subjected to axial loads (tensile and pressure), and little subjected to bending loads (lateral forces). The opening of the frame 3, between the frame members 11-14 has a width WF which is sufficiently wide for receiving a child support, such as for instance a seat 25 as illustrated in FIGs. 12, 13 or a cradle 26, as illustrated in FIGs. 14, 15. The support is preferably detachably mountable to the frame members 11-14, by means of suitable fastening means, such as for instance snap-fasteners, press-buttons, hook-in means, clips, barbed tape or the like. This enables use of the buggy 1 with several types of child support, such as the ones shown in FIGs. 12-15. Moreover, it allows for easy removal of the child support before bringing the buggy in collapsed condition, allowing the use of seats 25 and cradles 26 of relatively stiff, noncollapsible design. Alternatively, the child support can be of collapsible design, for instance made of a flexible material, stretched between the frame members 11-14. To that end, the frame members 11-14 can be bent in any suitable way, to allow the support to be stretched around these members in an ergonomic way. As the collapsible child support does not necessarily have to be removed before bringing the buggy 1 in collapsed condition, convenience of use is even further served, without compromising the sitting comfort. Notice that in FIGs 1-11 the child support has been omitted for clarity sake.

The buggy 1 may further comprise a foot support 28, which, mounted just above the front wheel 4, may serve as a mud flap for said wheel 4 at the same time. The front and/or rear wheels 4, 5 can be provided with one or more brake systems. For instance, the front wheel 4 may be provided with two brake shoes, operable by a user by means of a brake cable leading up to the handle 17. Such brake facility may assist the user in negotiating steep slopes. Furthermore, one or each rear wheel 5 may be provided with blocking means (not shown), for parking the buggy 1. Such blocking means could for instance be activated by a food pedal.

The buggy 1 as described above can be brought from its extended condition shown in FIGs. 1-5 to a collapsed condition shown in FIGs. 6-8, and in more detail in FIGs. 9-11. To that end, the central pivot means 8 are unlocked and the upper frame part 6 is pushed downward so as to pivot around central pivot axis C towards the lower frame part 7, as indicated by arrow P (FIG. 1). This pivot movement is transferred to the mounting brackets 22 via the rods 24, causing the mounting brackets 22 to pivot around their respective pivot axes M in a direction as indicated by arrows R (FIG. 4). Consequently, the rear wheels 5 will be moved simultaneously towards the front wheel 4 and each other, as illustrated in three consecutive steps in FIGs. 9-11.

In the final collapsed condition (FIGs. 6-8) the mounting brackets 22 extend substantially parallel to each other, at a distance S (see FIGs. 7, 8, 11), flanking opposite sides of front wheel 4. The rear wheels 5 extend at least partially next to said front wheel 4, with the axes of rotation A,B of the wheels 4,5 extending substantially parallel to each other and preferably at the same height above the ground. The rear wheels 5 are flanked by the upper frame members 11, 12. Hence, the width W_w of the wheelbase in extended condition is reduced to a width Wwcoi in collapsed condition, which is smaller than the width WF of the frame 3, and therefore the overall width of the buggy 1 in collapsed condition is determined by the width of the frame 3 rather than the width of the wheelbase. Likewise, the length L_w_oi of the wheel base in collapsed condition is considerably smaller than the length L in extended condition and could in theory, with the axes of rotation A,B of the wheels 4,5 being aligned in collapsed condition be as small as the diameter of said wheels 4, 5. In a preferred collapsed condition, the handle 17 is pivoted so as to embraces the rear wheels 5 at least partially. In this way, the handle 17 can protect the wheels 5 against undesired external shocks, which could harm the wheels during transportation.

It will be appreciated that through a suitable dimensioning and orientation of the various frame parts, a buggy can be conceived having a large wheel base with a relatively low centre of gravity, situated well within the boundary of said wheel base, and hence featuring excellent stability and road- holding in unfolded condition, while in collapsed condition having a very compact, handy size, enabling easy storage, transportation and other handling.

In the present embodiment this is achieved by choosing the length LM of the mounting brackets 22, measured between axis of rotation B and pivot axis M (see FIG. 3) to be approximately equal to the length LF of the front fork 19 measured between pivot axis M and the axis of rotation A. Furthermore, the orientation of the pivot axes M of the mounting brackets 22 (that is the angle α with rotation axis B, and the angle γ with the horizontal plane) is chosen such, that in extended condition, in extended condition the angle φ of divergence between the mounting brackets 22 (see FIG. 4) and the angle β between the mounting brackets 22 and the front fork 19 (see FIG. 3) are relatively large. The large angle β (in this embodiment approximately 85 degrees) provides for a long wheel base L ₎ a relative low positioned cross bar 20 and consequently a relatively low position of the child support 25, 26 resulting in a relatively low centre of gravity, which is beneficial for the stability of the buggy 1. The large angle φ results in the buggy having a wide, stable wheel base W in extended condition.

The orientation of the pivot axes M furthermore allows the brackets to extend approximately parallel to each other in collapsed condition (see FIG. 7), resulting in a very small wheelbase and hence small overall width and length dimensions of the buggy 1 in collapsed condition.

Furthermore, the central pivot means are positioned approximately halfway the frame 3, so that the length L_Up of the upper frame part 6, measured between pivot axis C and hinge 18, approximately equals the length Lb of the lower frame part 7, measured between central pivot means 8 and rotation axis A. Hence, in collapsed condition, the frame 3 can substantially be folded double, resulting in a small overall height H_coι. Moreover, the pivot axis of hinge 18 will extend approximately at the same height above the ground as the rotation axes A, B of the wheels 4,5 and in a preferred embodiment be aligned with at least the axes B of the rear wheels 5. It will be appreciated that the use of the two independent mounting brackets 22 according to the present invention for suspending the rear wheels 5, obviates the need of a fixed (rear) axle extending between the rear wheels 5, as common in many known buggies. Thanks to the absence of such fixed axle, free space is obtained below the frame 3 between the rear wheels 5, which may be used for walking, or can be used as additional storing space. To that end a netting member or the like can be mounted below the child support, at least partially extending between said brackets 22. Moreover, the independent suspension of the rear wheels 5 allows these wheels 5 to negotiate irregularities in the road surface, such as bumps and potholes, independently of each other, which may even further increase the stability of the buggy as well as the riding comfort.

The invention is not limited in any way to exemplary embodiments shown in the description and the figures. Many variations thereof are possible within the scope of the invention outlined by the claims. For instance, the buggy can comprise two front wheels instead of one, which can be folded in a comparable way as described for the rear wheels, to a collapsed condition in which the front and rear wheels lie side by side (wherein either of the wheels may occupy an outside or inside position) and the axes of rotation of said wheels are preferably aligned. Also the at least one front wheel and/or the rear wheels may be detachable, preferably by means of a quick release system. This allows the wheels of the buggy to be interchanged easily for other or larger wheel types, to adapt the buggy for all terrain purposes. Moreover, it allows the size of the buggy in collapsed condition to be reduced even further. The buggy can be marketed with several types and/or sizes of seats and cradles, additional wheels (larger size) and other accessories, such as brakes, a carrying handle 29 (see FIG. 2) for carrying the collapsed buggy in a most appropriate, balanced way, like a suitcase, etc. Furthermore, the fold and unfold operation can be even further facilitated by providing the frame with suitable drive means, such as biased (gas, hydraulic or mechanical) spring means, which may, upon activation, complete the desired pivot movements automatically or semi-automatically. The frame and mounting brackets can be made of metal, especially aluminum or steel, or plastic or a combination of both.

These and many comparable variations are understood to fall within the scope of the invention as outlined by the claims.

Claims

1. Collapsible buggy, provided with at least a front wheel (4), two rear wheels (5) and a frame (3), wherein each (rear) wheel (5) is carried by a mounting bracket (22) which is pivotally connected to the frame (3) through pivot means (23), wherein the pivot means (23) of each mounting bracket (22) include an axis (M) which in normal operating condition includes an angle with the longitudinal direction of the axes (B) of the (rear) wheels (5), wherein the (rear) wheels (5) together with the mounting brackets (22) are pivotable relative to the frame (3) and each other towards a collapsed condition.

2. Collapsible buggy according to claim 1, wherein the pivot means (23) are arranged in such way that by collapsing the buggy (1) the (rear) wheels (5) together with the mounting brackets (22) move towards each other as well as in the direction of the at least one (front) wheel (4).

3. Collapsible buggy according to claim 1 or 2, wherein the frame (3) is configured in such way that in the collapsed condition the (rear) wheels (5) extend at least partially adjacent the at least one (front) wheel (4), preferably a (rear) wheel (5) at either side thereof, wherein a portion (11, 12, 17) of the frame (3), in particular a handle portion (17) thereof, extends next to the (rear) wheels (5).

4. Collapsible buggy according to anyone of the preceding claims, wherein each mounting bracket (22) for suspension of a (rear) wheel (5) is configured as a multiple rod assembly, in particular a four rod assembly, in such way that when pivoting said brackets (22) the (rear) wheels (5) remain substantially parallel to each other.

5. Collapsible buggy according to anyone of the preceding claims, wherein the mounting brackets (22) are mutually coupled through or in the proximity of the pivot means (23) in such way that they can be pivoted together.

6. Collapsible buggy according to any one of the preceding claims, wherein the frame (3) comprises at least two frame members (11, 13; 12, 14), which near their upper ends are interconnected by a handle portion (17) and at some distance from their lower end are interconnected by a cross bar (20), extending approximately parallel to the axes (B) of the (rear) wheels (5), wherein the frame members (11, 13; 12, 14), at least a portion thereof extending between said handle portion (17) and said cross bar (20), extend substantially parallel, at a distance (WF) from each other, which is sufficiently wide for receiving a child support, such as for instance a seat (25) or a cradle (26), between said frame members (11-14).

7. Collapsible buggy according to claim 6, wherein the mounting brackets (22) carrying the rear wheels (5) are pivotally connected to the cross bar (20), and wherein the lower portions of the frame members (13, 14), extending beyond said cross bar (20), diverge towards each other so as to form a front fork (19), in which the front wheel (4) is mounted.

8. Collapsible buggy according to claim 7, wherein the length (LM) of each mounting bracket (22), measured between the pivot axis (M) and the rear wheel axis (B) of said mounting bracket (22), is substantially equal to the length (LF) of the front fork (19) carrying the front wheel (4), measured between said pivot axis (M) and the front wheel axis (A).

9. Collapsible buggy according to claim 8, wherein the angle between the pivot axes (M) of the mounting brackets (22) and the axes (B) of the rear wheels (5) is chosen such, in combination with the length (LM) of said brackets (22), that the width (W_w) of the wheel base of the rear wheels (5) in extended condition is larger than the width (WF) between frame members (11, 12), while the width (W_WCoi) of said wheel base in collapsed condition is smaller than said frame width (WF).

10. Collapsible buggy according to any one of claims 7-9, wherein with the buggy (1) in extended condition, each mounting bracket (22), seen in side view, includes an angle (β) with the front fork (19), which angle (β) is relatively large, specifically more than 75 degrees, more specifically more than 80 degrees and preferably around 90 degrees or more.

11. Collapsible buggy according to any one of claims 6-10, wherein the frame (3) comprises an upper frame part (6) and a lower frame part (7), said upper frame part (6) comprising upper frame members (11, 12) and handle (17), said lower frame part (7) comprising lower frame members (13, 14) and cross bar (20), wherein the upper and lower frame part (6, 7) are pivotally connected by pivot means (8) around a central pivot axis (C), which pivot axis (C) extends substantially parallel to the axes (B) of the rear wheels (5) and, seen in top plan view, with the buggy (1) in extended condition, is positioned between the axes (A,B) of the front and rear wheels (4, 5), more particularly between the cross bar (20) and the axes (B) of the rear wheels (5).

12. Collapsible buggy according to claim 11, wherein the mounting brackets (22) are coupled to the upper frame part (6) by coupling means, in such way that upon pivoting the upper frame part (6) around central pivot axis (C) towards, respectively away from the lower frame part (7), said coupling means push, respectively pull the mounting brackets (22) around the respective pivot axes (M) into a collapsed, respectively extended condition.

13. Collapsible buggy according to claim 12, wherein the coupling means comprise two rods (24), each pivotally connected to the upper frame part (6) and a mounting bracket (22), in such way that with the buggy (1) in extended condition, the rods (24) extend substantially vertical, at least seen in side view.

14. Collapsible buggy according to any one of claims 11-13, wherein the handle (17) is pivotally connected to upper frame members (11, 12) via pivot means (18), around a pivot axis extending substantially parallel to the central pivot axis (C).

15. Collapsible buggy according to claim 14, wherein the length (L_up) of the upper frame part (6), measured between the central pivot axis (C) and the pivot axis (18) of the handle (17), is substantially equal to the length (Lι₀) of the lower frame part (7), measured between the central pivot axis (C) and the front wheel axis (A).

16. Collapsible buggy according to any one of claims 11-15, wherein with the buggy (1) in collapsed condition, the rear wheels (5) extend between frame members (11, 12) of upper frame part (6) and the pivot axis of handle (17) extends approximately in line with the axes (B) of the rear wheels (5).

17. Collapsible buggy according to any one of the preceding claims, wherein with the buggy (1) in collapsed condition the mounting brackets (22) extend substantially parallel, at some distance (S) from each other, and front wheel (4) extends between said mounting brackets (22).

18. Collapsible buggy according to any one of claims 6-17, wherein the child support (25, 26) is detachably mountable to the frame (3).

19. Collapsible buggy according to any one of claims 6-18, wherein the child support (25, 26) is made of a flexible, foldable material, in such way that it can be brought in collapsed condition together with the frame (3).

20. Collapsible buggy according to any one of the preceding claims, wherein the frame (3), in particular one of the frame members (11-14) is provided with a carrying handle, for carrying the buggy (1) in collapsed condition.

21. Collapsible buggy according to any one of the preceding claims, wherein locking means are provided, to lock the central pivot means (8) at least with the buggy (1) in extended condition.

22. Collapsible buggy according to any one of the preceding claims, wherein drive means are provided, for example biased spring means, for assisting pivot movement of the buggy (1) from the collapsed into the extended condition and/or vice versa.