WO2006029468A1

WO2006029468A1 - Folding mechanism for a hand-propelled vehicle

Info

Publication number: WO2006029468A1
Application number: PCT/AU2005/001409
Authority: WO
Inventors: Aydin Keyvanloo
Original assignee: Igc (Australia) Pty Ltd
Priority date: 2004-09-15
Filing date: 2005-09-15
Publication date: 2006-03-23

Abstract

A compactly collapsible sub-frame for a hand-propelled vehicle includes a transverse frame member (29), and a first elongate frame member (30) projecting from and mounted to the transverse frame member for pivoting movement between a lowered, retracted position and an upstanding position. A second elongate frame member (32) is slidably supported with respect to the first elongate frame member, with the two members generally parallel, for providing an extension of the first elongate frame member. A slide member (34) is carried by the first elongate frame member and is longitudinally translatable therealong, and a strut (40) for the first elongate frame member is coupled to the slide member. The arrangement is such that, on being withdrawn outwardly from the first elongate frame member (30), the second elongate frame member (32) engages the slide member (34) at a position intermediate its fully retracted and fully extended positions to thereafter move the slide member (34) along the first elongate frame member and thereby to pull the strut (40) from a withdrawn position to an operative position

Description

FOLDING MECHANISM FOR A HAND-PROPELLED VEHICLE

Field of the invention

This invention relates to hand-propelled vehicles, particularly baby and child carriages or strollers. In one aspect, the invention is directed to a compactly collapsible sub-frame for such vehicles.

Definitions

It is to be understood that, in the context of this specification, the term "hand- propelled" refers to the action of pushing or pulling a vehicle while walking adjacent to it. It will also be appreciated that the Australian term "stroller" is equivalent to "pushchair" or "pusher" in other countries. Reference to a chassis is to be taken as including reference to a framework.

Background of the invention

There are many types of commercially available strollers that offer various combinations of advantageous features to appeal to the consumer. Steering systems, seat adjustment, weight, and braking mechanisms, for example, are a few of the common features that customers consider when purchasing a stroller for use.

Another of the features that can influence a consumer's purchase is the ease with which the stroller can be extended from its collapsed or storage position to its in- use position, and vice versa. Associated factors include the ability to securely lock the stroller against accidental collapse during use, and the overall size of the stroller when it is collapsed to its storage position. The overall size of the stroller when collapsed is an important consideration as strollers are commonly transported in the boot or trunk of a car together with other articles, and this importance is amplified when the stroller is fitted with large diameter wheels. It is an object of this invention to provide an improved folding mechanism for a hand-propelled vehicle that at least in part incorporates at least some of the desirable features outlined above.

It is a further object of the invention to provide a compactly collapsible sub-frame adaptable for use in a folding frame for a hand-propelled vehicle.

Summary of the invention

In a first aspect, the invention provides a hand-propelled vehicle, including a chassis which mounts rearward ground wheels and forward ground wheels, and a handle frame suitable to be grasped by hand for propelling the vehicle on said ground wheels over an underlying ground or floor surface. The handle frame includes: a pair of outer tubular members connected to the chassis, a pair of middle tubular members respectively received and movable within the outer tubular members, and a pair of slide members respectively received and movable within the outer tubular members. The middle tubular members are respectively interconnected with the slide members such that movement of the middle tubular members from a collapsed position within the outer tubular members to an extended position, causes the slide members to correspondingly move from a collapsed position to an extended position, to extend the handle frame from a collapsed position to an extended in use position, and vice versa.

The handle frame is preferably substantially U-shaped, with the respective tubular members forming a pair of side arms, connected at their upper end to form a handle. The outer tubular members are preferably pivotally attached to the chassis.

In a particularly preferred embodiment, the vehicle further includes a pair of struts that assist in supporting the handle frame in its extended position. The respective struts are preferably pivotally connected at one end to the chassis, and at the other end pivotally connected to the slide members. A slot or groove is preferably provided in each of the outer tubular members to enable the struts and slide members to be connected. Advantageously, movement of the slide members from a collapsed position to an extended position correspondingly moves the struts from a collapsed position to an extended position, and vice versa.

When the respective tubular members are in the collapsed configuration, the middle tubular members are preferably substantially wholly nested within the outer tubular members.

The chassis of the vehicle is preferably configured to be substantially planar, and in a particularly advantageous embodiment, the respective tubular members and struts lie in the plane of the chassis when in the collapsed configuration.

In a preferred embodiment the interconnection of the middle tubular and slide members is achieved via a pin and slot type arrangement. Each of the slide members preferably includes an elongate slot or channel extending substantially the length of the slide member. The middle tubular members preferably include a pin or the like, which is sized and shaped to be slidably received within the channel of the slide members. The pin is preferably provided at or towards the lower end of the middle tubular member.

Preferably, means are provided to lock the tubular members against movement with respect to each other when in the extended configuration. In a preferred embodiment, the seat of the stroller includes such locking means.

The handle of the stroller is preferably connected to upper ends of the middle tubular members.

In a second aspect, the invention provides a compactly collapsible sub-frame for a hand-propelled vehicle, including a transverse frame member, and a first elongate frame member projecting from and mounted to the transverse frame member for pivoting movement between a lowered, retracted position and an upstanding position. A second elongate frame member is slidably supported with respect to the first elongate frame member, with the two members generally parallel, for providing an extension of the first elongate frame member. A slide member is carried by the first elongate frame member and is longitudinally translatable therealong, and a strut for the first elongate frame member is coupled to the slide member. The arrangement is such that, on being withdrawn outwardly from the first elongate frame member, the second frame member engages the slide member at a position intermediate its fully retracted and fully extended positions to thereafter move the slide member along the first elongate frame member and thereby to pull the strut from a withdrawn position to an operative position.

Typically, there are two of said sub-frames at respective sides of a frame further including a chassis and a handle linking the sub-frames.

In this second aspect of the invention, said first and second elongate frame members are preferably respective tubular members inter-engaged telescopically.

The slide member may be an elongate bar or plate, preferably having a longitudinally extending slot slidably engaged by pin means on said second elongate frame member.

Preferably, the first and second elongate frame members carry latching members that are mutually co-operable in the fully extended position of the second elongate frame member relative to the first elongate frame member for releasably latching the members in that position. The latching member carried by the second elongate frame member is advantageously connected to the second elongate frame member via a first slot in the first elongate frame member.

In an embodiment, said latching members inter-engage to define a closed structure about a cavity, and there is further provided a locking formation releasably engagable with said closed structure and having both a male component to occupy said cavity and a female component to embrace said closed structure to prevent separation thereof into said latching members, and means actuable to release said engagement of the locking formation with said closed structure.

Preferably, said strut is coupled to the slide member via a second slot in the first elongate frame member. Advantageously, said first and second slots are aligned or contiguous, or, in a preferred embodiment, the same slot.

In a third aspect, the invention provides a mechanism for locking a pair of parallel elongate members in a fixed relationship, including respective complementary latching members carried by the elongate members that inter-engage to define a closed structure about a cavity, and a locking formation releasably engageable with the closed structure and having both a male component to occupy the cavity and a female component to engage the closed structure to prevent separation thereof into said latching members.

Preferably, the female component engages said closed structure to prevent separation thereof into said latching members by at least partly embracing the closed structure.

The mechanism may further include means actuable by hand to release the engagement of the locking formation with the closed structure.

There may also be hand-releasable means to latch together said latching members.

Brief Description of the Drawings

The invention will now be further described by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a side view of a stroller in an extended configuration in accordance with an embodiment of the invention;

Figure 2 is a perspective view of the stroller of Figure 1 with the seat removed for clarity;

Figure 31s an enlarged view of the front wheel axle and a strut of the stroller of Figure 1 ; Figure 4 is an enlarged view of the front wheel axle and handle of the stroller of Figure 1 ;

Figure 5 is a perspective view of the stroller as in Figure 2 showing the handle partially collapsed;

Figure 6 is a top plan view of the stroller of Figure 1 in its collapsed configuration;

Figure 7 is a diagrammatic view showing the internal connections of the tubular members in an extended configuration;

Figure 8 is a diagrammatic view showing the internal connections of the tubular members of Figure 7 in a collapsed configuration;

Figure 9 is a partly cutaway view of an alternative configuration;

Figure 10 and 11 are partly sectioned side views of an alternative form of the latching configuration, respectively shown just prior to or after inter-engagement of the components, with Figure 11 also showing part of a seat unit ready to engage the latching configuration; and

Figure 12 is a fragmentary perspective view of the latching configuration as seen in Figure 11.

Description of Preferred Embodiments

Referring to Figures 1 and 2 of the drawings, there is shown a stroller 10. Stroller

10 includes chassis 12 which supports rear ground wheels 14 and forward ground wheels 16 in a conventional manner. Chassis 12 is preferably substantially planar. The form of chassis shown is for illustration only and it will be appreciated that other chassis designs could be used with the invention.

Figure 1 shows the stroller 10 in an extended, in use configuration with a child or baby seat 18 attached. Child seat 18 has been removed in Figure 2 for clarity. Referring to Figure 1 , stroller 10 includes substantially a U-shaped handle frame, generally designated 20. Handle frame 20 takes the form of a pair of side arms 22, 24, and a crossbar 26 that joins the upper ends of side arms 22, 24 to form the actual handle.

Each of side arms 22, 24 includes an outer tubular member 30, middle tubular member 32, and inner tubular member 34 (as seen in Figures 7 and 8).

Outer tubular members 30 are pivotally connected at their lower ends to a common transverse chassis member 29 at pivot connections 31 , such that the outer tubular members 30 can pivotally collapse rearwardly alongside chassis 12 as shown in Figure 6. The upper ends of outer tubular members 30 are preferably provided with an external latch formation 33 that comprises a sleeve 35 and substantially vertical upwardly directed arm 36. Arm 36 further includes a cut-out section 37. Sleeve 35 is fixed to the outer periphery of each of the outer tubular members. Each of the outer tubular members is hollow such that middle tubular members 32 and inner tubular members 34 can nest within, as shown in Figures 7 and 8.

Each of the outer tubular members 30 is further provided with an elongate slot or channel 38, as best seen in Figure 3. The slots 38 extend partway along the lower end and on the inboard side of outer tubular members 30 to provide access for a pair of struts 40 to inner tubular members 34, as will be discussed in further detail below.

The middle tubular members 32 nest within and are slidable relative to the outer tubular members 30 from a collapsed position within the outer tubular members 30 (Figure 8) to an extended position as shown in Figures 1 and 7, for example. Figure 5 shows the middle tubular members 32 partially collapsed.

Handle 26 is attached to the respective upper ends of middle tubular members 32. In the embodiment illustrated, handle 26 is fixed relative to the middle tubular members 32. It will be appreciated that handle 26 may be pivotably relative to the middle tubular members to provide different angles of use for an operator, and furthermore may be height adjustable in a conventional manner. Each of middle tubular members 32 preferably also includes an external latch formation 43 that comprises a sleeve 42 and substantially vertical upwardly directed arm 44, essentially the same in form as, and complementary to, the sleeve 35 and arm 36 of the outer tubular members 30. Arm 44 further includes a cut-out section 39. Sleeve 42 is fixed to the outer periphery of each of the middle tubular members 32. An elongate slot or channel 46 is provided in each of the outer tubular members 30 to enable sleeve 42 to be connected to middle tubular members 32 via a radial bar 41. Slot 46 extends substantially the length of outer tubular members 30 as best shown in Figure 4.

The lower ends of middle tubular members 32 are further provided with a pin 50 or the like. Pin 50 extends inwardly of the middle tubular members 32 to engage an elongate slot 52 provided in each of inner tubular members 34, as discussed below.

Inner tubular members 34 are contained wholly within the outer and middle tubular members 30, 32, as best shown in Figures 7 and 8, and are slidable relative to both the outer and middle tubular members 30, 32. Each of the inner tubular members 34 includes the aforementioned elongate slot 52 which extends substantially the length of the inner tubular members 34 as illustrated. Pin 50 of the middle tubular members engages slot 52. As discussed below, movement of middle tubular members 32 relative to the outer tubular members 30 results in corresponding movement of pin 50 along slot 52.

The lower ends of inner tubular members 34 are pivotally connected via lateral links 53 and pivot 54 to respective upper ends of struts 40. Links 53 project through slots 38. The lower ends of struts 40 are in turn pivotally connected to chassis 12 at pivots 56.

As described above, and as illustrated, slots 38 and 46 in outer tubular members

30 are separately provided and are relatively angularly displaced in tubular members 30. In another embodiment, slots 38 and 46 may be combined to form a single, contiguous slot or channel. Such a channel would preferably be stepped to so as to provide an upper limit on the travel of struts 40 while still enabling full movement of middle tubular members 32 within the outer tubular members 30.

In order to extend the stroller 10, starting from the collapsed configuration shown in Figure 6, an operator grips the handle 26 or side arms 22, 24 (effectively outer tubular members 30) and lifts the side arms 22, 24 upwardly, pivoting at pivot points 31 until the side arms extend upwardly from, and at an angle relative to, chassis 12 as shown in

Figure 5.

The handle 26 is then extended to its in use position. To do this, the operator grips the handle 26 and pulls it upwardly in order to extend middle tubular members 32 from within the outer tubular members 30. Pin 50, which is at the lower end of slot 52 when the stroller is collapsed, moves upwardly along slot 52 as the handle (and middle tubular members 32) are extended. Sleeve 42 and arm 44 also move upwardly with the middle tubular members 32 via slot 46.

As the middle tubular members 32 are extended, each pin 50 reaches the upper end of its slot 52. As the middle tubular members 32 continue to be extended, the action of pins 50 against the upper ends of slots 52 causes the inner tubular members

34 to be pulled and thereby to slide upwardly within outer tubular members 30.

Movement of the inner tubular members 34 in turn pulls the upper ends of struts 40 upwardly within slots 38. This continues until the middle tubular members 32 are fully extended and struts 40 are fully extended. Sleeve 42 and arm 44 abut the sleeve 35 and arm 36 when the handle 26 is fully extended. As arms 44 and 36 abut, cut out sections 37 and 39 form a hole or opening 41 which is used to lock the arms together, as discussed in further detail below.

Various means may be employed to lock the handle in its fully extended position to prevent accidental collapse of the stroller during use. In a particularly preferred embodiment of the invention, child seat 18 is provided with a pair of locking mechanisms 60 provided on either side of the seat 18 as shown in Figure 1. Each of the locking mechanisms 60 includes a recess (not shown) formed in its lower face. The recess is sized and shaped to receive each of arms 44 and 36 when they are abutting. Locking mechanisms 60 each include a pin or button (not shown) that is biased outwardly such that when the arms 44 and 36 are inserted into the recess, the pin engages opening 41 to lock arms 44 and 36 together. A push button 43 or other means is provided on the locking mechanisms 60 to remove the pin from the opening 41 to enable the seat 18 to be removed from the stroller 10 so that the stroller can be collapsed.

In order to collapse the stroller 10, seat 18 is first removed to unlock the arms 44 and 36. Handle 26 is then pushed by the operator downwardly such that the middle tubular members 32 slide within the outer tubular members 30. As this occurs, pin 50 slides along slot 52 from the upper end until it reaches the lower end of slot 52. Once the lower end of slot 52 is reached, pin 52 continues to moves downwardly and pulls inner tubular members 34 downwardly.

Struts 40 are caused to collapse as the inner tubular members 34 move downwardly. Struts 40 collapse forwardly to lie in the plane of the chassis 12. When the handle is fully collapsed, side arms 22, 24 are pivoted downwardly and rearwardly about pivot connections 32 to also lie in the plane of chassis 12.

As shown in Figure 6, rear ground wheels 14 are preferably disposed inwardly of the forward ground wheels 16 so that handle 26 and side arms 22, 24 surround and are not obstructed by the rear wheels 16 when the stroller 10 is collapsed, in order to minimise the space taken up by the stroller in its collapsed configuration.

In an alternative embodiment, depicted in partial cut-away in Figure 9, the innermost member of the telescopic configuration is not a tubular member (as at 34 in the embodiment of Figures 1 to 8) but an elongate bar or plate 134. In general in Figure 9, parts corresponding to like parts of Figures 1 to 8 are indicated by the same reference numeral preceded by a "1". This embodiment also adopts the aforementioned modification in which slots 38, 46 are aligned or contiguous, in this case as a common slot 138/146: link 153 to strut 140 projects through and slides along the lower end 138 of the slot, while bar 141 for the latch formation on tubular member 132 slides along the slot 146 ahead of link 153.

It will be appreciated that the operational principle of the Figure 9 embodiment is similar to that of Figures 1 to 8, but this embodiment, with a single slot in each of the outer tubular member 130 and the inner plate 134, is more economical to manufacture as an assembly.

In this embodiment, the upper end of travel of the plate 134 and strut 140 is determined by a fixed stop 149 on the inside of tube 130 that is engaged by strut link 153 while being clear of pin 150 on middle tubular member 132.

An alternative latching/locking configuration will now be described with reference to Figures 10 to 12. Again, parts corresponding to the like parts of Figures 1 to 8 are indicated by the same reference numeral preceded by a "1". In this case, the respective latch formations 133, 143 on each side of the stroller comprise complementary U- shaped members 70, 71 that engage in the fully extended position of the handle to define a closed structure in the form of a hollow rectangular block 72 about an open- topped central cavity 73. Locking formation 160 on each side of the seat 118 has a central tongue or spigot 74 that serves as a male component snugly receivable in cavity 73, and a broad tray-shaped part 76 that serves as a female component to embrace rectangular block 72 to prevent separation of members 70, 71.

The tongue 74, engages the central cavity 73 and is latched therein by any suitable releasable mechanism, e.g. a pair of retractable spring-loaded catches 78 that engage recesses 79 in the rectangular block 72. (The catch release lever is not shown). When the spigot is latched, the female part 76 embraces the rectangular block 72 in a manner that positively prevents separation of the elements of the block because their line of separation is angled to the vertical centre line of interlocked parts.

The latching arrangement is completed by a hand-releasable mechanism 80 for latching formations 133, 143 together. Mechanism 80 comprises a forward projection 82 on formation 133 that has a scallop recess 84 for T-shaped lever 86 on formation 143. Lever 86 is pivoted at 87, is displaceable by a chamfered front edge 83 of projection 82 as the parts come together, and is releasable by pulling on a spring-loaded trigger 85 mounted within a hand-grip saddle 88 of formation 143.

It will be seen that, when the seat is in position on the stroller with locking formation 160 in place on the rectangular block 72, the stroller cannot be inadvertently collapsed, and two separate hand-release actions are necessary before collapsing can commence.

It will be further appreciated that the folding or collapsing mechanism of the invention enables fast and easy erection and collapse of the stroller. The overall size of the stroller when it is collapsed is minimised by having the chassis and handle means lie in the same plane when collapsed. An important preferred aspect is the way a necessary weight-bearing brace for the upper structure is provided in the guise of struts 40, 140, and yet a mechanism has been achieved where these struts can collapse into the same plane as the chassis and handle. Means are also provided for locking the stroller against accidental collapse when it is being used.

Claims

1. A compactly collapsible sub-frame for a hand-propelled vehicle, including:

a transverse frame member;

a first elongate frame member projecting from and mounted to said transverse frame member for pivoting movement between a lowered, retracted position and an upstanding position;

a second elongate frame member slidably supported with respect to said first elongate frame member, with the two members generally parallel, for providing an extension of the first elongate frame member;

a slide member carried by said first elongate frame member and longitudinally translatable therealong; and

a strut for said first elongate frame member coupled to said slide member;

wherein, on being withdrawn outwardly from said first elongate frame member, said second elongate frame member engages the slide member at a position intermediate the second elongate frame member's fully retracted and fully extended positions to thereafter move the slide member along said first elongate frame member and thereby to pull the strut from a withdrawn position to an operative position.

2. A compactly collapsible sub-frame according to claim 1 wherein said first and second elongate frame members are respective tubular members inter-engaged telescopically.

3. A compactly collapsible sub-frame according to claim 2 wherein said slide member is a further tubular member inter-engaged telescopically with said respective tubular members.

4. A compactly collapsible sub-frame according to claim 1 or 2 wherein said slide member is an elongate bar or plate.

5. A compactly collapsible sub-frame according to any one of claims 1 to 4 wherein said slide member has a longitudinally extending slot slidably engaged by pin means on said second elongate frame member.

6. A compactly collapsible sub-frame according to any one of claims 1 to 5 wherein said first and second elongate frame members carry latching members that are mutually co-operable in the fully extended position of the second elongate frame member relative to the first elongate frame member for releasably latching the members in that position.

7. A compactly collapsible sub-frame according to claim 6 wherein the latching member carried by the second elongate frame member is connected to the second elongate frame member via a first slot in the first elongate frame member.

8. A compactly collapsible sub-frame according to claim 7 wherein said strut is coupled to the slide member via a second slot in the first elongate frame member, and wherein said first and second slots are aligned or contiguous.

9. A compactly collapsible sub-frame according to claim 8 wherein said first and second slots are the same slot.

10. A compactly collapsible sub-frame according to any one of claims 6 to 9 wherein said latching members inter-engage to define a closed structure about a cavity, and there is further provided a locking formation releasably engageable with said closed structure and having both a male component to occupy said cavity and a female component to engage said closed structure to prevent separation thereof into said latching members.

11. A compactly collapsible sub-frame according to any one of claims 1 to 5 wherein said strut is coupled to the slide member via a slot in the first elongate frame member.

12. A hand-propelled vehicle, the vehicle including a chassis which mounts rearward ground wheels and forward ground wheels, and a pair of sub-frames according to any one of claims 1 to 11 , linked by a handle suitable to be grasped by hand for propelling the vehicle on said ground wheels over an underlying ground or floor surface.

13. A hand-propelled vehicle according to claim 12, wherein said transverse frame members of said sub-frames comprise a member of said chassis that is common to both sub-frames.

14. A hand-propelled vehicle according to claim 12 or 13 when appended to claim 10 wherein said locking formation of each sub-frame is provided on a seat unit of the vehicle.

15. A hand-propelled vehicle according to any one of claims 12 to 14, wherein, in the fully retractable position of the second frame members and the withdrawn position of the strut, the respective compactly collapsible sub-frames lie outside the rearward ground wheels and inside the forward ground wheels so that the vehicle is in a collapsed condition for carriage or transport.

16. A hand-propelled vehicle according to any one of claims 12 to 15 wherein said chassis is configured to be substantially planar and wherein, in the fully retracted position of the second frame members and the withdrawn position of the strut, the respective compactly collapsible sub-frames lie substantially in the plane of the chassis so that the vehicle is in a collapsed condition for carriage or transport.

17. A hand-propelled vehicle according to any one of claims 12 to 16 wherein said hand-propelled vehicle is a baby or child carriage or stroller.

18. A hand-propelled vehicle, the vehicle including a chassis which mounts rearward ground wheels and forward ground wheels, and a handle frame suitable to be grasped by hand for propelling the vehicle on said ground wheels over an underlying ground or floor surface, wherein the handle frame includes: a pair of outer tubular members connected to the chassis;

a pair of middle tubular members respectively received and movable within the outer tubular members; and

a pair of slide members respectively received and movable within the outer tubular members;

wherein the middle tubular members are respectively interconnected with the slide members such that movement of the middle tubular members from a collapsed position within the outer tubular members to an extended position, causes the slide members to correspondingly move from a collapsed position to an extended position, to extend the handle frame from a collapsed position to an extended in-use position, and vice versa.

19. A hand-propelled vehicle according to claim 18 wherein said handle frame is substantially U-shaped, with the respective tubular members forming a pair of side arms, connected at their upper end to form a handle.

20. A hand-propelled vehicle according to claim 18 or 19 wherein said outer tubular members are pivotally attached to the chassis.

21. A hand-propelled vehicle according to claim 18, 19 or 20, further including a pair of struts that assist in supporting the handle frame in its extended position.

22. A hand-propelled vehicle according to claim 20 wherein said respective struts are pivotally connected at one end to the chassis and at the other end to the slide members.

23. A hand-propelled vehicle according to claim 21 or 22 wherein a slot or groove is provided in each of the outer tubular members to enable the struts and slide members to be pairwise connected.

24. A hand-propelled vehicle according to claim 21 , 22 or 23 wherein movement of the slide members from a collapsed position to an extended position correspondingly moves the struts from a collapsed position to an extended position, and vice versa.

25. A hand-propelled vehicle according to any one of claims 18 to 24 wherein said chassis is configured to be substantially planar, and the respective tubular members and struts lie substantially in the plane of the chassis when in the collapsed configuration.

26. A hand-propelled vehicle according to any one of claims 18 to 25 wherein when the respective tubular members are in the collapsed configuration, the middle tubular members are substantially wholly nested within the outer tubular members.

27. A hand-propelled vehicle according to any one of claims 18 to 26 wherein the interconnection of the middle tubular and slide members is achieved via a pin and slot arrangement, each of the slide members including an elongate slot or channel extending substantially the length of the slide member, and the middle tubular members including a pin or the like, which is sized and shaped to be slidably received within the slots or channels of the slide members.

28. A hand-propelled vehicle according to claim 27 wherein the pin is provided at or towards the lower end of the middle tubular member.

29. A hand-propelled vehicle according to any one of claims 18 to 28, further including means to lock the elongate frame members against movement with respect to each other when in the extended configuration.

30. A hand-propelled vehicle according to claim 29 wherein a seat of the vehicle includes said lock means.

31. A hand-propelled vehicle according to claim 29 or 30 wherein the handle of the vehicle is connected to upper ends of the middle tubular members.

32. A hand-propelled vehicle according to any one of claims 18 to 31 wherein said hand-propelled vehicle is a baby or child carriage or stroller.

33. A mechanism for locking a pair of parallel elongate members in a fixed relationship, including:

respective complementary latching members carried by said elongate members that inter-engage to define a closed structure about a cavity: and

a locking formation releasably engageable with said closed structure and having both a male component to occupy said cavity and a female component to engage said closed structure to prevent separation thereof into said latching members.

34. A mechanism according to claim 33 where said female component engages said closed structure to prevent separation thereof into said latching members by at least partly embracing the closed structure.

35. A mechanism according to claim 33 or 34 further including hand-releasable means to latch together said latching members.

36. A mechanism according to claim 33,34 or 35 further including means actuable by hand to release said engagement of the locking formation with said closed structure.