WO2011042561A1

WO2011042561A1 - Rotating joint for folding pushchair frame

Info

Publication number: WO2011042561A1
Application number: PCT/EP2010/065148
Authority: WO
Inventors: John Anderson
Original assignee: Armon Ltd
Current assignee: Armon Ltd
Priority date: 2009-10-08
Filing date: 2010-10-08
Publication date: 2011-04-14
Anticipated expiration: 2012-04-08
Also published as: GB0921389D0; GB201016738D0; GB2474359A; GB201017021D0

Abstract

A joint (10,10' ) for a folding pushchair frame comprises first and second plastics shells joined coaxially in opposed relation for rotation about a pin. First and second rigid struts (11,12) are fixed respectively to the two shells so that their respective central longitudinal axes extending through the joint are spaced apart in all positions of the joint in both axial and radial directions of the pivot axis. The two shells define an internal cavity (25,35) containing abutment surfaces (26,36) which cooperate to define the folded position of the joint. The struts (11,12) are spaced apart to define a minimum distance of separation in the folded position in an oblique direction with respect to the pivot axis (P), so that the joint avoids presenting a finger trap while remaining relatively compact.

Description

Rotating joint for folding pushchair frame

This invention relates to pivoting joints which connect adjacent ends of two rigid struts in a folding pushchair frame so that the struts can be pivoted between a use position in which they extend in generally opposite directions and a folded position in which they lie substantially side-by-side.

Pushchairs, also referred to as buggies or strollers, are used for carrying small children and are commonly provided with folding frames so that they can be stowed away, for example in a car or on public transport.

It is important that the frame should fold as compactly as possible, otherwise the pushchair will be inconvenient in use. It is also important that the frame does not provide finger traps, i.e. gaps which are wide enough to allow a child to insert his or her finger, but too narrow to allow it to be easily withdrawn without a significant risk of injury. It is also important that the joint should be simple and economical.

It is the object of the present invention to provide an improved joint for a folding pushchair frame that better satisfies these sometimes conflicting requirements.

According to the present invention there is provided a folding pushchair comprising a pair of rotating joints as defined in the claims. Further features and advantages will be evident from the various illustrative embodiments which will now be described, purely by way of example and without limitation to the scope of the claims, and with reference to the accompanying drawings, in which: Figs. 1 A, 2 A and 3 A are respectively a right side, left side and front view of a first, left-hand rotating joint in the unfolded position;

Figs. IB, 2B and 3B correspond respectively to Figs. 1 A, 2A and 3 A, showing the first j oint in the folded position;

Fig. 1C is an oblique view of the first joint in the folded position;

Figs. 4 A and 4B show a second, right-hand rotating joint similar to the first joint, respectively with the second body portion removed (Fig. 4A) and with the first strut and body portion removed (Fig. 4B);

Fig. 5 shows part of a single-seat pushchair frame incorporating the first and second joints;

Fig. 6 shows part of a double seat pushchair frame incorporating the first and second joints;

Fig. 7 shows an alternative single-seat pushchair frame incorporating the first and second joints, in which the upper and lower struts are curved; and

Figs. 8, 9 and 10 are respectively a side, bottom and perspective view of a single- seat pushchair incorporating the frame of Fig. 5. Corresponding parts are indicated by the same reference numerals in each of the figures.

Referring to Fig. 5 and to Figs. 8, 9 and 10, a folding pushchair frame 1 comprises a left-hand rotating joint 10 and a right-hand rotating joint 10', arranged in opposed relation on either side of the seat 2 on a common pivot axis P. Each joint connects an upper rigid metallic strut 11, 11 ' having a handle 13 at its upper end to a lower rigid metallic strut (12, 12') having a front wheel 14 arranged at its lower end, the struts extending generally transversely to the pivot axis. Apart from the joints 10, 10', the remaining details of the pushchair are conventional. The pushchair has at least three wheels, and preferably two front wheels 14 and two rear wheels 14' as shown since this provides a stable configuration, although in alternative embodiments it may have two rear wheels and one front wheel (in which case the lower struts 12, 12' may converge downwardly), or even two front wheels and one rear wheel. Double pushchairs may have more than four wheels.

Referring also to Figs. 1 - 4, the left-hand joint 10 comprises a first moulded plastics body portion 20 having a socket portion 27 connected in fixed relation to the lower end of the upper left-hand strut 11, and a second moulded plastics body portion 30 having a socket portion 37 connected in fixed relation to the upper end of the lower left-hand strut 12. The right-hand joint 10' is oppositely handed but otherwise exactly similar to the left-hand joint 10, comprising a first body portion 20' connected in fixed relation to the lower end of the upper right-hand strut 11 ', and a second body portion 30' connected in fixed relation to the upper end of the lower right-hand strut 12'.

Each pair of body portions 20, 30 (20', 30') are pivotably and coaxially connected together by a rivet 3 which defines the pivot axis P about which they rotate, one relative to the other. Each of the body portions 20 (20'), 30 (30') comprises a moulded plastics shell defining a surface of rotation 21, 31, which blends on the outer side of the body portion into an end surface 22, 32 generally normal to the pivot axis. Both surfaces 21, 31 are of generally equal radius about the pivot axis P adjacent the sliding joint between them, as shown. The surfaces 21, 31, 22, 32 form the outer surface of the joint, so that it is bounded radially with respect to the pivot axis by the respective surfaces of rotation 21, 31 and in opposite axial directions of the pivot axis P by the respective end surfaces 22, 32 of the first and second body portions.

Each surface of rotation terminates on the inner side of the body portion at an annular sliding surface 23, 33 (Figs. 4A, 4B) which lie in mutually opposed relation in a common plane normal to the pivot axis P, so that the two body portions of each joint lie in sliding abutment with the two surfaces 23, 33 sliding past each other as the joint rotates. Advantageously, the joint thus comprises only the two body portions together with the rivet 3, making it very economical to manufacture and simple to assemble. In an alternative embodiment, a washer or other additional part might be interposed between the two body portions. In each case however, there is advantageously no gap between the two body portions which might form a finger trap, so that the two body portions of each joint form cooperating, rounded shells which safely enclose the rivet 3 and other internal moving structures and which meet at a sliding interface.

As seen in figs. 4A and 4B, each of the body portions 20, 30 (20', 30') is provided with an internal abutment comprising a block 24, 34, each block extending to form a protrusion which is received in an internal annular cavity 35, 25 that extends part- way round the circumference of the respective other body portion. The blocks define cooperating abutment surfaces 26, 36 which define the maximum range of rotation of up to about 160 to 180 degrees about the pivot axis P between the first and second body portions and thus between the respective pair of struts to which they are attached, from the fully unfolded, use position in which the upper and lower struts 11, 12 (1 Γ, 12') extend away from the joint in generally opposite directions as shown in Figs. 1 A, 2A, 3A, and 5, to the fully folded position in which they lie side-by-side in spaced relation as shown in Figs. IB, 1C, 2B, and 3B. Since the abutment surfaces are entirely enclosed within the joint, there is no danger of trapping a finger between them. In the fully folded position, the upper and lower struts and also the respective socket portions 27, 37 are spaced apart proximate the respective joint by a minimum distance defining a non-reducible gap D2 sufficient to avoid a finger trap (Fig. 1C), and are folded together in side- by-side relation so that they are slightly divergent, defining an angle of about 10 degrees to 15 degrees between them, which angle is selected as required according to the other characteristics of the pushchair, for example, to accommodate the folded fabric surrounding the seat. In alternative embodiments the two struts may be parallel in the folded position. The gap D2 is widest in an oblique direction relative to the pivot axis P as shown and increases in width as the frame is unfolded, so that the frame can be folded compactly but the two struts can never form a finger trap. Instead of or additionally to enclosing the abutments within the first and second body portions of each respective joint as shown, the frame 1 may include separate abutments spaced apart from the joints which limit rotation at each respective joint to define the folded position of the frame. For example, end regions of the respective upper and lower struts 11, 12, 11 ', 12' adjacent the wheels and handles, or a continuous handlebar abutting against the lower front struts, or any other suitable portions of the frame may be arranged to abut one another to define the fully folded position. Alternatively, each joint may include external abutments, in which case they are preferably arranged so as to be inaccessible to small fingers. As shown in Fig. 2B, the central longitudinal axis LI of the lower strut 12 (12') (which is to say, the imaginary line lying along the centre of the strut and extending beyond its ends and through the joint) is spaced radially from the pivot axis P so that it is tangent to an imaginary arc Al defined by a first radius Rl of the pivot axis P, while the central longitudinal axis L2 of the upper strut 11 (1 Γ) intersects the pivot axis P. The respective central longitudinal axes LI, L2 of the lower and upper struts are also spaced apart by a distance Dl in the axial direction of the pivot axis P, as shown in Fig. 3A.

As best seen in the folded position in Fig. 3B, when considered in a direction normal to the axes LI, L2 and to the pivot axis P, the axial separation Dl between the two struts leaves the socket portions 27, 37 of the two body portions as well as the further ends of the two struts slightly overlapping in the axial direction of the pivot axis. As seen in Fig. IB, when considered in the axial direction of the pivot axis P, the socket portions 27, 37 are also close together. However, when considered in the folded position in an oblique direction as shown in Fig. 1C, a substantial distance of separation D2 is evident between the two socket portions 27, 37, which distance is sufficiently large that the two socket portions and the two struts 11, 12 do not form a finger trap. This separation is achieved without sacrificing the overall compactness of the joint in the axial direction (as shown in Fig. 3B) or in the radial direction of the pivot axis, as shown in Fig. IB. The combination of both radial and axial offsets between the two struts thus achieves a compact joint which at the same time avoids presenting a finger trap in the folded position.

The respective imaginary central longitudinal axes LI, L2 of the lower and upper struts extending through the joint are thus spaced apart in all positions of the joint in both axial and radial directions of the pivot axis P, so that, irrespective of their relative rotational positions between the folded position and the unfolded position, the two struts are never exactly superimposed and conterminous when considered in a direction either along (Figs. 1 A, IB) or normal to (Figs. 3 A, 3B) the pivot axis. When considered in a direction normal to their respective longitudinal axes and normal to the pivot axis P in the folded position, as illustrated by Fig. 3B, the two struts lie side by side and are offset from one another; they may overlap as shown, or alternatively they may be spaced apart for the whole of their length.

In an alternative embodiment illustrated by the alternative position 1 l" of the upper strut shown in dotted lines in Fig. 2A, instead of intersecting the pivot axis P, the central longitudinal axis L2' of the upper strut 11" may be tangential to an arc A2 defined by a second radius R2 of the pivot axis. The second radius R2 is smaller than the first radius Rl as shown, so that a radius R_P of the pivot axis P lies parallel with and just outside the upper strut 11". In a yet further alternative embodiment (not shown), the radius R2 is yet smaller, so that the radius R_P of the pivot axis lies within the upper strut 11" and parallel with its central longitudinal axis L2\ In each case, the separation between the upper and lower struts in the folded position is advantageously increased, ensuring that no finger trap is created when the frame is folded, without substantially increasing the overall width of the folded joint.

When considered from the direction shown in Fig. 3B, the axes LI, L2 of the two struts are slightly divergent in the folded position. This allows the handlebar to be the same width as the footrest and so helps the pushchair to fold more compactly. Alternatively they may be parallel when considered from this direction, which is to say, they may lie in two parallel planes normal to the pivot axis P, in which case the handlebar is slightly wider than the footrest, which additional width may advantageously be used to accommodate a removable car seat. As shown in Fig. 2A, the socket portion 37 of the second body portion 30 lies partially radially outwardly and partially radially inwardly of its surface of rotation 31, so that a tangent Tlof the surface of rotation 31 of the second body portion 30 lies within the lower strut 12 and parallel with its central longitudinal axis LI. This increases the separation between the two struts without increasing the diameter of the body portions, so that the joint remains relatively compact. Referring to Fig. 6, in an alternative embodiment the left- and right-hand rotating joints 10, 10' are incorporated into a second folding pushchair frame 4 which includes two seats 5, 5' arranged side by side and an intermediate joint 6 arranged between them. The intermediate joint has a pivot axis P arranged coaxially between the rotating joints 10, 10' and provides pivotal movement between first and second intermediate rigid struts 7, 8 arranged between the two seats. Unlike the joints 10, 10', the intermediate joint 6 is arranged so that the central longitudinal axes of the intermediate struts 7, 8 lie in a common plane normal to the pivot axis throughout their range of movement between the unfolded position shown and the folded position (not shown). The central longitudinal axis of the upper intermediate strut 7 intersects the pivot axis P, while that of the lower intermediate strut is spaced radially from the pivot axis. The intermediate struts are thus spaced apart in the radial direction of the pivot axis but not in its axial direction.

In order to facilitate branding of the product, an annular element 40 is preferably attached to one of the body portions, so that the visible face 41 of the annular element carrying suitable indicia 42 is arranged at the end surface of the body portion as shown. The annular element can conveniently be made as an interchangeable insert that is snap- fitted into a recess in the body portion after assembly of the joint, which allows relatively small batches of product to be selectively branded after manufacture. Referring lastly to Fig. 7, in an alternative pushchair frame 70, rather than being straight, the upper struts 71, 71' and lower struts 72, 72' may be curved, in which case the central longitudinal axis L3, L4 of each strut is taken to be the imaginary line lying along the centre of the strut and extending beyond its ends and through the joint and following the curvature of the strut, as shown. Similarly to the foregoing embodiments, the axes L3, L4 are spaced apart in all positions of the joint in both axial and radial directions of the pivot axis.

The casing of the joint may also incorporate a cylindrical attachment point for the attachment of accessories such as parasols, drink holders, trays and the like, which enables the accessories to remain in place on the stroller frame when it is folded.

In summary, a preferred joint for a folding pushchair frame comprises first and second plastics shells joined coaxially in opposed relation for rotation about a pin. First and second rigid struts are fixed respectively to the two shells so that their respective central longitudinal axes extending through the joint are spaced apart in all positions of the joint in both axial and radial directions of the pivot axis. The two shells define an internal cavity containing abutment surfaces which cooperate to define the folded position of the joint. The struts are spaced apart to define a minimum distance of separation in the folded position in an oblique direction with respect to the pivot axis, so that the joint avoids presenting a finger trap while remaining relatively compact.

Of course, the relative geometries of the upper and lower struts might be reversed, and the range of movement between the two struts may similarly be adapted to suit the requirements of the frame. The body portions could be made from metal rather than plastic. The struts may be round or non-round in cross section. Many other adaptations falling within the scope of the claims will be evident to those skilled in the art.

Claims

1. A folding pushchair including a frame and at least three wheels, the frame including a pair of rotating joints arranged in opposed relation on respective opposite sides of the frame, each rotating joint connecting together a respective pair of first and second rigid struts, each strut having a respective central longitudinal axis, the first and second struts of each pair being pivotable about a pivot axis between a folded position of the frame in which they lie side-by-side and an unfolded position of the frame in which they extend away from the joint in generally opposite directions; each joint including a first body portion connected in fixed relation to an end of the respective first strut and a second body portion connected in fixed relation to an end of the respective second strut, the first and second body portions being connected coaxially for rotation one relative to the other about the pivot axis, wherein the respective central longitudinal axes of the first and second struts extending through the joint are spaced apart in all positions of the joint in both axial and radial directions of the pivot axis.

2. A folding pushchair according to claim 1, wherein in each respective joint the central longitudinal axis of the first strut is tangential to an arc defined by a first radius of the pivot axis and the central longitudinal axis of the second strut is tangential to an arc defined by a second radius of the pivot axis smaller than the first radius.

3. A folding pushchair according to claim 2, wherein in each respective joint a radius of the pivot axis lies within the second strut and parallel with its central longitudinal axis.

4. A folding pushchair according to claim 1, wherein in each respective joint the central longitudinal axis of the second strut intersects the pivot axis.

5. A folding pushchair according to claim 1, wherein in each respective joint the first and second struts overlap in the axial direction of the pivot axis.

6. A folding pushchair according to claim 1, wherein in each respective joint, each of the first and second body portions defines a respective surface of rotation about the pivot axis, and the joint is bounded radially with respect to the pivot axis by the respective surfaces of rotation.

7. A folding pushchair according to claim 1, wherein in each respective joint the first body portion defines a surface of rotation about the pivot axis, and a tangent of the surface of rotation lies within the first strut and parallel with its central longitudinal axis.

8. A folding pushchair according to claim 1, wherein each respective joint is bounded in opposite axial directions of the pivot axis by respective end surfaces of the first and second body portions.

9. A folding pushchair according to claim 1, wherein in each respective joint the first and second body portions define respective first and second, mutually opposed sliding surfaces, each sliding surface lying in a plane normal to the pivot axis.

10. A folding pushchair according to claim 9, wherein in each respective joint the sliding surfaces lie in a common plane such that the first and second body portions slidingly abut one another.

11. A folding pushchair according to claim 9, wherein the first and second body portions define respective first and second surfaces of rotation of equal radius about the pivot axis, the first and second surfaces of rotation lying adjacent respectively the first and second sliding surfaces.

12. A folding pushchair according to claim 1, wherein the frame includes abutments which limit rotation at each respective joint to define the folded position of the frame, and the first and second struts of each pair are spaced apart proximate the respective joint by a non-reducible gap in the folded position, the gap being widest in an oblique direction relative to the pivot axis and increasing in width as the frame is unfolded.

13. A folding pushchair according to claim 12, wherein first and second said abutments are enclosed within the first and second body portions of each respective j oint.

14. A folding pushchair according to claim 8, wherein in each respective joint an annular element is attached to a said body portion, the annular element having a visible face arranged at the end surface thereof.

15. A folding pushchair as defined in any preceding claim, wherein the frame includes two seats arranged side by side and an intermediate joint, the

intermediate joint having a pivot axis arranged coaxially between the said pair of rotating joints and providing pivotal movement between first and second intermediate rigid struts arranged between the two seats.

16. A folding pushchair substantially as described with reference to the accompanying drawings.