GB2050495A

GB2050495A - Pivotable Joints

Info

Publication number: GB2050495A
Application number: GB7919744A
Authority: GB
Original assignee: MACLAREN Ltd A
Current assignee: MACLAREN Ltd A
Priority date: 1979-06-06
Filing date: 1979-06-06
Publication date: 1981-01-07

Abstract

A pivotable joint for connecting two linear members comprises a first structure (2) having a first aperture (6) through which can be inserted one of the linear members and also having a second aperture (5) in which is journalled for rotation a second structure 8 having an aperture (12) through which can be inserted the second linear member. The insertion of the two linear members in their respective apertures (6 and 12) is arranged to secure the second structure (8) in the first structure (2), while permitting relative rotation of the first structure and second structure, thereby to provide pivotal movement of the two linear members. <IMAGE>

Description

SPECIFICATION Pivotable Joints Technicai Field of the Invention This invention relates to pivotable joints for pivotally connecting together two members and has an important application to pivotable joints such as are used in foldable baby carriages and push chairs.

Background Art Such pivotable joints usually connect together two generally linear members at a position intermediate their ends and in a manner such that the two members can be pivoted between a first position in which they extend substantially parallel to one another and a second position in which the two members extend transversally to one another. Hitherto, it has been proposed to provide aligned holes in the two members through which extend a pivot pin which provides the necessary pivotal movement. However, this previously proposed arrangement may not be entirely satisfactory, since the provision of suitable holes in the two members to accommodate a strong and durable pivot pin may weaken one or both members.Moreover, the repeated pivotal movement of the two members, for example when incorporated in a foldable baby carriage or push-chair, may result in the pivot pin or the holes in the two members becoming worn or distored so that the pivotable joint is not as stable as it should be.

Disclosure of the Invention According to the present invention a pivotable joint for pivotably connecting two members comprises a first structure having a first aperture through which can be inserted one of the members and also having a second aperture in which is journalled for rotation a second structure having an aperture through which can be inserted the second member, the insertion of the two members in their respective apertures being arranged to secure the second structure in the second aperture of the first structure while permitting relative rotation of the second structure in the second aperture thereby to provide the pivotal movement of the two members.

Preferably the first structure is provided with two aligned apertures through which can be inserted the first member, and the second aperture in which is journalled for rotation the second structure, is located between the two aligned apertures and provides an axis of rotation which is normal to the longitudinal axis of the first member.

The first structure may comprise two generally cylindrical end portions provided with the aligned apertures and connected together by a hollow cylindrical portion which defines the second ?perturb in which is journalled the second structure.

The first and second structures may be formed from material having a relatively low co-efficient of friction. Preferably the first and second structures are moulded from a plastics material.

The second structure may be substantially cylindrical and may be provided with an annular flange which bears against an internal annular flange within the second aperture of the first structure to provide bearing surfaces affording rotation.

An embodiment of the invention will now be described, by way of example with reference to the accompanying drawings.

Brief Description of the Drawings Figure 1 is an exploded perspective view of a pivotable joint in accordance with the invention; Figure 2 is a side elevation of two tubular members connected together by a pivotable joint as shown in Figure 1, with the tubular members lying parallel to one another; Figure 3 is a plan view of the arrangement shown in Figure 2 but with the tubular members lying transversely of one another; and Figure 4 is a perspective view of a baby carriage incorporating pivotable joints as shown in Figure 1.

Best Mode for Carrying out the Invention Referring in the first instance to Figure 1, the pivotable joint 1 comprises a first structure 2 formed by moulding of plastics material such as nylon or polypropylene, having two generally cylindrical end portions 3 connected together by a hollow, generally cylindrical, portion 4 defining an aperture 5 of substantially circular cross-section.

Aligned apertures 6, having a substantially circular cross-section, are provided in the end portions 3 and are arranged to receive a first linear tubular member of a metal such as aluminium. The common axis of the apertures 6 is normal to the axis of the circular aperture 5 in the cylindrical portion 4.

A generally cylindrical structure 8, also moulded from a suitable plastics material such as nylon or polypropylene is journalled for rotation within the aperture 5 in the hollow cylindrical portion 4. An annular flange 9 at one end of the cylindrical structure 8 mates with an internal annual flange 10 within the cylindrical portion 4 when the cylindrical portion 8 is inserted within the hollow cylindrical portion 5, the flanges 9 and 10 about one another and form a bearing surface for relative rotation between the two structures 2 and 8. An aperture 12, of circular cross-section, extends through the cylindrical structure 8 with its axis normal to the rotational axis of the cylindrical structure. The aperture 1 2 is arranged to receive a second tubular member of metal such as aluminium.

When the cylindrical structure 8 is inserted within the hollow cylindrical portion 5 the stem 14 of the cylindrical structure 8, which contains the aperture 12, projects beyond a surface 1 5 so that a portion of the circumference of the aperture 12 lies substantially flush with the surface 1 5.

When the cylindrical portion 5 is inserted in this way the upper surface of the flange 9 lies substantially flush with a portion of the circumference of the aperture 6. Thus when a tubular member 7 is inserted in the aperture 6, as shown in Figures 2 and 3 the circumference of the tubular member 7 bears against the upper surface 1 6 of the cylindrical structure 8 and secures the cylindrical structure 8 within the hollow cylindrical portion 5. Similarly, when a tubular member 13 is inserted within aperture 12, as shown in Figures 2 and 3 the circumference of the tubular member 13 bears against the surface 1 5 of the structure 2 and secures the cylindrical structure 8 within the hollow cylindrical portion 5.

When the pivotable joint 1 and the tubular members 7 and 13 are assembled in the manner described above, the tubular members may be pivoted through 360 degrees, and can assume intermediate positions such as that shown in Figure 2, in which the tubular members 13 and 7 lie substantially parallel to one another and that shown in Figure 3. in which the tubular members extend substantially at right-angles to one another. To prevent longitudinal movement of the members 7 and 1 3 in their respective structures 2 and 8, a pin 17 may be inserted through the surface 1 6 into the adjacent wall of the tubular member 7 and pins 18 may be inserted through the upper surface of the end portions 3 and 4 into the adjacent wall of the tubular member 7.

Pivotable joints as described above may be incorporated in a baby carriage 20 as shown in Figure 4. As can be seen in Figure 4 a bottom Xframe 22 comprises two linear tubular members 23 and 24 pivotally connected together by a pivotable joint 1 in accordance with the invention.

Similarly, two linear tubular members 25 and 26 also form an X-frame 27 located in an upright plane which is inclined at a fairly small angle to the vertical.

The adjacent ends of the tubular members 23, 24, 25 and 26 are conjoined articulately, and it is convenient to think of the two X-frames 22 and 27 as "lazy tongs" linkage in two planes. It follows that if either X-frame 22 or 27 is collapsed about its pivotable joint 1, the other Xframe must collapse in a similar manner. When the X-frame 22 and 27 are collapsed, the members 23, 24,25 and 26, lie nearly parallel to one another, since with both X-frames collapsed together the four tubular members 23, 24, 25 and 26 assume a near mutually parallel relationship.

The baby carriage 20 incorporating pivotable joints 1 in accordance with the invention in this manner has the advantage that it avoids drilling relatively large holes in the tubular members 23, 24, 25 and 26 to accommodate pivot pins which might weaken them. Moreover, since the bearing surfaces of the pivotable joints according to the invention are relatively large compared with the bearing surfaces associated with pivot pins extending through the tubular members 23, 24, 25 and 26, the wear or damage caused by repeated pivotal movement is much less than would occur with pivotable joints incorporating a pivot pin.Furthermore, the pivotable joints 1 can conveniently be moulded from a plastics material which has a low co-efficient of friction and can therefore provide a pivotable joint which can be manipulated repeatedly and yet remain relatively rigid over a long period of time.

While the embodiment of the invention shown in the drawings has structures 2 and 8 formed with cylindrical or arcuate contours having no pronounced edges and is therefore eminently suitable for incorporation in a baby carriage, in other embodiments of the invention the structures 2 and 8 may be generally rectangular or have other geometric shapes. Moreover, while the structure 2 shown in the drawings is provided with two aligned apertures 6 into which a tubular member 7 can be inserted, in other embodiments of the invention the structure 2 may have a single aperture into which a linear member can be inserted. Finally, it will be appreciated that it is not essential for the apertures 6 and 12 to be substantially circular in cross-section as shown in the drawings, and that they can be of other crosssectional shapes provided that the linear members to be inserted therein are of corresponding cross-sectional shape.

Claims

1. A pivotable joint for pivotally connecting two members (7 and 1 3) characterised by: a first structure (2) having a first aperture (6) through which can be inserted one of the members (7) and also having a second aperture (5) in which is journalled for rotation a second structure (8) having an aperture (2) through which can be inserted the second member (13); the insertion of the two members (7 and 13) in their respective apertures (6 and 12) being arranged to secure the second structure (8) in the first structure (2), while permitting relative rotation of the first structure and the second structure, thereby to provide pivotal movement of the two members (7 and 13).

2. A pivotable joint as claimed in Claim 1, characterised in that the first structure (2) is provided with two aligned apertures (6) through which can be inserted a first member (7), and the second aperture (4) in which is journalled for rotation the second structure (8) is located between the two aligned apertures and provides an axis of rotation which is normal to the longitudinal axis of the first member when inserted.

3. A pivotable joint as claimed in Claim 2, characterised in that first structure (2) comprises two generally cylindrical end portions (3) provided with the aligned apertures (6) and connected together by a hollow cylindrical portion (4) which defines the second aperture (5) in which is journalled the second structure (8).

4. A pivotable joint as claimed in any preceding claim, characterised in that the first and second structures (2 and 8) are formed from a material having a relatively low co-efficient of friction.

5. A pivotable joint as claimed in any preceding claim, characterised in that the first and second structures (2 and 8) are formed from a plastics material.

6. A pivotable joint as claimed in any preceding claim, characterised in that the second structure (8) is substantially cylindrical and is provided with an annular flange (9) which bears against an internal annular flange (10) within the second aperture (5) of the first structure (2) to provide bearing surfaces affording rotation.

7. A pivotable joint as claimed in any preceding claim, characterised in that the first aperture (6) in the first structure (2) and the aperture (12) in the second structure (8) are substantially circular in cross-section.

8. A foldable structure incorporating at least one pivotable joint (1) as claimed in any preceding claim.

9. A foldable baby carriage incorporating at least one pivotable joint as claimed in any one of Claims 1 to 7.

10. A pivotable joint substantially as hereinbefore described with reference to Figure 1 of the accompanying drawings.

11. A pivotable joint arranged to connect for pivotal movement two linear tubular members as hereinbefore described with reference to Figures 2 and 3 of the accompanying drawings.

1 2. A foldable baby carriage incorporating at least one pivotable joint construction and arranged to operate substantially as hereinbefore described with reference to Figure 4 of the accompanying drawings.