GB2401647A

GB2401647A - Swivel joint and playground attraction comprising such a joint

Info

Publication number: GB2401647A
Application number: GB0310879A
Authority: GB
Inventors: Andrew Yates; David Richards
Original assignee: SMP Playgrounds Ltd
Current assignee: SMP Playgrounds Ltd
Priority date: 2003-05-12
Filing date: 2003-05-12
Publication date: 2004-11-17
Anticipated expiration: 2023-05-12
Also published as: GB0310879D0; GB2401647B

Abstract

A swivel joint (40) comprises first and second members rotatably connected to one another; the first member (46) comprising a body and two flanges (50, 86, 88) extending radially from a longitudinal axis of the body; and the second member (68) being located between and retained connected to the first member (46) by said two flanges (50, 86, 88). One of said flanges (86, 88) is secured to the body (46) by means of a releasable connection which constrains relative movement between the body and said one flange so that said one flange (86, 88) is releasable from the body (46) only in a generally radial direction from the longitudinal axis of the body (46). The joint is particularly applicable to a swing.

Description

SWIVEL JOINT AND PLAYGROUND ATTRACTION

COMPRISING SUCH A JOINT

The present invention relates to a swivel joint and playground attraction comprising such a joint.

Playground attractions (such as a swing) wherein one component is rotatably mounted to another component are well known and typically comprise a standard off-the-shelf mechanical universal joint (the construction of which will be well understood by those skilled in the art) . A problem associated with this type of prior art joint is that, if the pivot pins used in the joint fail for any reason, then the joint will effectively fall apart. As a consequence, the two components connected by the universal joint (ie the swing frame and swing seat) must be tethered to each other. Also, these prior art joints (and their tether mechanisms) are not tamperproof. In other words, it is possible for a user of the playground attraction to interfere with the joint and potentially insert objects or fingers. These problems can have very dangerous consequences.

It is an object ofthe present invention to provide an improved swivel joint.

A first aspect of the present invention provides a swivel joint comprising first and second members rotatably connected to one another; the first member comprising a body and two flanges extending radially from a longitudinal axis of the body; and the second member being located between and retained connected to the first member by said two flanges; wherein one of said flanges is secured to the body by means of a releaseable connection; characterized in that said releaseable connection constrains relative movement between the body and said one flange so that said one flange is releaseable from the body only in a generally radially direction from the longitudinal axis of the body.

Thus, in use of a swivel joint according to the present invention, the body of the first member may be arranged with the longitudinal axis oriented vertically. The second member may then be prevented from dropping from the first member by means of one of the flanges. The other of said two flanges will prevent the second member from being lifted from the first member. This second flange is preferably releaseably connected to the body and the constraining of relative movement between the body and the second flange so that the flange is releaseable only in a generally radial direction allows an arrangement wherein the flange cannot simply fall from the body under the action of gravity. The arrangement also allows a housing spaced radially from the swivel joint (and in which the swivel joint is mounted) to prevent release of the flange from the body and also to prevent access by a user to the flange.

Furthermore, the releaseable connection ideally comprises a surface on the body of the first member, which surface extends radially for engagement with said one flange and generally faces the other of said flanges. The surface on the body may define part of a recess in the body. Also, the recess preferably defines a fiat face lying in a plane parallel to and radially offset from the longitudinal axis of the body. The surface on the body may also lie in a plane extending perpendicularly to the longitudinal axis of the body. Said one flange preferably comprises a planar member having a slot defined by two spaced apart edges which face each other. Said spaced apart edges are ideally parallel to each other. It is also preferable for the edges to be spaced by a distance substantially equal to the radial thickness of the body portion located immediately adjacent said surface on the body and located between said surface and the other of said flanges.

A second aspect of the present invention provides a playground attraction comprising a swivel joint as hereinbefore described with reference to the first aspect of the present invention.

A third aspect of the present invention provides a playground swing comprising a swivel joint as hereinbefore described with reference to the first aspect of the present invention.

An embodiment of the present invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a plan view of a swivel joint according to the present invention; Figure 2 is a crosssectional side view of the swivel joint of Figure 1; Figure 3 is a crosssectional side view of the swivel joint shown in Figure 1; Figure 4 is an expanded perspective view of a shaft and bearing assembly of the swivel joint shown in Figure 1; Figure 5 is a cross-sectional side view of the shaft and bearings of Figure 4 appropriately assembled; Figure 6 is a cross-sectional side view of a support member for rotatably mounting to the shaft of Figures 4 and 5; Figure 7 is an expanded perspective view of the support member of Figure 6 in association with the shaft and bearings of Figures 4 and 5; Figure 8 is an expanded perspective view of the shaft, bearings and support member of Figure 7 appropriately assembled together with retaining components; Figure 9 is a cross-sectional side view of the shaft, bearings, support member and retaining components of Figure 8 appropriately assembled; Figure 10 is a perspective view of the assembly shown in Figure 9 being inserted into a mounting structure; and Figure 11 is an expanded view of the mounting structure in association with an access cover plate and a temporary transportation protector.

A swivel joint 40 according to the present invention is shown in Figures 1, 2 and 3 of the accompanying drawings in use with a tripod type of playground swing. In the plan view of Figure 1 the swivel joint 40 can be seen located in a central housing 42 to which three legs 44 of the swing structure are connected. The three legs 44 of the tripod swing frame extend from the ground to a central point (a central housing 42) from which a swing seat (not shown) is suspended on four chains via a swivel joint.

The swivel joint 40 comprises a support shaft 46. The support shaft 46 has an elongate cylindrical shape. One end of the support shaft 46 is provided with an eyebolt 48 screwthreaded therewith and the distal end of the shaft 46 is provided with a flange 50 which defines an upwardly facing annular shoulder surface 52 (see Figure 4) lying in a plane perpendicular to the longitudinal axis 53 of the shaft 46. It will be understood that the eyebolt 48 allows the swivel joint 40 to be conveniently lowered into the central housing 42. Similarly, the eyebolt 48 allows authorised personnel to lift the swivel joint from the housing 42 for routine maintenance work.

Upper and lower bearing races 54, 56 are located either side of a spacer ring 58 and located about the shaft 46 and retained one above the other on the shoulder surface 52 (see Figure 5 in particular). The outer diameters of the flange SO, spacer ring 58, and upper and lower bearing races 54, 56 are substantially identical. When the upper and lower bearing races 54, 56 and spacer ring 58 are located on the shoulder surface 52, the bearing races 54, 56 and spacer ring 58 extend just under halfway along the shaft 46.

With particular reference to Figure 4, it will be seen that the end portion of the shaft 46 distal to the shaft end having the flange 50 is provided with two flat surfaces 60, 62 (only one of which is shown in Figure 4) recessed into the outer cylindrical shaft surface. The two flat surfaces 60, 62 lie in two parallel planes which are parallel to the longitudinal axis 53. Furthermore, the flat surfaces 60, 62 are located on opposite sides of the shaft 46 and each define a downwardly facing shoulder 64 and an upwardly facing shoulder 66. The two downwardly facing shoulders 64 lie in one plane whilst the two upwardly facing shoulders 66 lie in a second plane. The two planes in which the shoulders 64, 66 lie extend perpendicularly to the longitudinal axis 53 of the support shaft 46.

A chain support member 68 is shown in Figure 6 for mounting in rotatable relationship with the support shaft 46. The chain support member 68 comprises a cylindrical body 70 having an internal diameter approximately the same as the external diameter of the shaft Hange 50 and bearing races 54, 56 and spacer ring 58 mounted thereon. An upper end of the cylindrical body 70 is provided with a radially inwardly projecting flange 72 which provides a downwardly facing annular shoulder 74. Four square-section elongate arm members 76 extend downwardly from the end of the body 70 distal to the body end having the flange 72. The arm members 76 are secured to the outer cylindrical surface of the body 70 and a radially outwardly projecting flange 78 extends from the outer surface of the body 70 in the region of the arm member 76 so as to provide said arm member 76 with lateral support (see Figures 7 and 8). Each arm member 76 is provided with an aperture 80 which facilitates attachment of a seat support chain to the associated arm member 76.

As illustrated in Figure 9, it will be seen that the chain support member 68 is located about the support shaft 46 with the downwardly facing shoulder 74 resting on the upper bearing race 54. The inner dimensions of the cylindrical body 70 are such as to house the flange 50, spacer ring 58, and upper and lower bearing races 54, 56. Thus, the distance from the shoulder 74 to the lower edge of the body 70 is approximately the same as the distance from the upper surface of the upper bearing race 54 to the lower surface of the flange 50. Also, the inner diameter of the cylindrical body 70 is only marginally greater than the outer diameter of the flange 50, spacer ring 58, and the upper and lower bearing races 54, 56. By virtue of the bearing races 54, 56 it will be appreciated that the chain support member 68 can freely rotate relative to the support shaft 46.

Axial movement of the chain support member 68 in one direction relative to the support shaft 46 is prevented by abutment of the shoulder 74 with the upper bearing race 54. Relative axial movement of the chain support member 68 in the opposite direction is prevented by abutment of the flange 72 with a spacer disc 82. The spacer disc 82 is secured, by means of four screws 84, to two slotted retaining discs 86, 88. As will be explained hereinafter, the retaining discs 86, 88 are secured to the support shaft 46 in such a way as to prevent relative axial or rotational movement between the slotted retaining discs 86, 88 and the support shaft 46. Accordingly, in the assembled swivel joint 40, the spacer disc 82 is also prevented from moving axially or rotationally relative to the support shaft 46. A thrust washer 90 is located between the spacer disc 82 and the flange 72 and axial movement of the chain support member 68 relative to the support shaft 46 is thereby prevented whilst permitting rotational movement between the support member 68 and shaft 46 permitted.

The slotted retaining discs 86, 88 are identical to one another. Each disc, 86, 88 is circular having a diameter greater than the outer diameters of the chain support member 68 and spacer disc 82. Thus, in the assembled swivel joint 40, the retaining discs 86, 88 project radially beyond the remainder of the swivel joint 40 and thereby provide a downwardly facing annular area which may engage an upwardly facing shoulder in the central housing 42. Each retaining disc 86, 88 is provided with a slot having a width substantially equal to the distance between the flat surfaces 60, 62 of the shaft 46. This arrangement is such that the recessed portion of the shaft 46 provided by the flat surfaces 60, 62 may be inserted into the slot 92 of a disc 86, 88 with very lime play between the two components so that relative rotation between the disc 86, 88 and the support shaft 46 is minimal. The slot 92 extends from a circumferential edge portion of a disc 86, 88 radially towards and beyond the centre of the disc 86, 88. The slot 92 extends beyond the centre of the disc 86, 88 by a distance of no less than the radius of the shaft 46 at the axial position of the flat surfaces 60, 62. In this way, each disc 86, 88 may be slotted about the flat surfaces 60, 62 and located coaxially with the support shaft 46. The depth of each disc 86, 88 is approximately half the distance between the downwardly and upwardly facing shoulders 64, 66 of the flat surfaces 60, 62. Thus, the two discs 86, 88 may be both slotted about the flat surfaces 60, 62 from opposite sides of the support shaft 46 (with one disc above the other) and locate in abutment with said shoulders 64, 66 with minimal play. In this way, relative axial and twisting movements between the discs 86, 88 and the support shall 46 are minimised. Indeed, the dimensions of the discs 86, 88 and their slots 92 in relation to the dimensions of the flat surfaces 60, 62 may be such that the discs 86, 88 locate with an interference fit with the shaft 46. A rigid connection between the discs 86, 88 and the support shaft 46 will be thereby provided. Nevertheless, in the particular embodiment shown, the screws 84 each extend through an aperture in each of the discs 86, 88 and screw threadedly engage with the spacer disc 82. The discs 86, 88 are then constrained from sliding from the support shaft 46.

The assembled swivel joint 40 is shown in Figure 9. It will be appreciated that the chain support member 68 is free to rotate relative to the shaft 46, spacer disc 82 and slotted retaining discs 86, 88.

Once assembled, the swivel joint 40 may be used in connection with a playground attraction such as a tripod swing. As illustrated in Figure 10, the swivel joint 40 may be lowered into the central housing 42 of a tripod swing frame and positioned so that an outer annular area of the retaining discs 86, 88 locates on an upwardly facing annular shoulder of said housing 42. As shown in Figure 2, the housing 42 may be manufactured from two separate cylindrical components 94, 96 so as to assist in the provision of the upwardly facing annular shoulder. The swivel joint 40 may be lowered into the housing 42 through use of the eyeball 48. Once in position, the aperture 98 in the housing 42 through which the joint 40 was lowered may be sealed with a cover plate 100. A protective cover 102 may also be placed over the open lower end of the housing 42 so as to cover the arm members 76 extending therefrom. The cover 102 may be retained in position by means of fasteners (eg screws) engaging with the arm apertures 80 (see Figure 2) .

In use, a swing seat is suspended on chains from the arm member 76. The swing seat (not shown) may rotate together with the chain support member 68 relative to the support shaft 46 and central housing 42. Relative rotational movement between the support shaft 46 and the housing 42 may be prevented by means of a screw 104 extending through the discs 86, 88 into the housing 42. The inner diameter of the central housing 42 is approximately equal to the outer diameter of the discs 86, 88 in the region above the upwardly facing annular shoulder of the housing 42. As such, a sliding movement of the retaining discs 86, 88 from the support shaft 46 once the swivel joint 40 is located within the housing 42 is prevented.

It will be appreciated that the arrangement of the swivel joint 40 is such that, once assembled and installed within the central housing 42, disassembly of the swivel joint 40 is not possible without removing the joint 40 from the housing 42. Such removal is only possible by authorised personnel who will need a suitable platform from which to work and appropriate lifting equipment. The housing cover plate 100 may also be locked (with, for example, tamper resistant bolts) to the housing 42 in order to improve security, and authorised personnel will then also require a key in order to gain access to the joint 40.

It will be appreciated that even if there is a mechanical failure of the fasteners 84, the chain support member 68 will remain rotatably mounted on the central housing 42.

Indeed, many components of the joint 40 may suffer mechanical failure without the joint as a whole degrading to an extent that safety is unduly compromised. For example, the bearings 54, 56 and/or housing screw 104 may fail without the joint 40 or any substantial component thereof falling from the housing 42 as a consequence. It will also be appreciated that location of the swivel joint 40 in a close fitting housing 42 prevents access to the joint 40 by fingers or other objects. The risk of fingers becoming trapped by the swivel joint 40 is therefore very small. The small spaces between the moving components ofthe joint 40 itself also ensure objects cannot become easily trapped.

The present invention is not limited to the particular embodiment described above.

Alternative arrangements will be apparent to a reader skilled in the art. For example, one or more slotted retaining discs may be used. It is also possible to provide the shaft 46 with just a single flat surface 60. - 8

Claims

CLAIMS: 1. A swivel joint comprising first and second members rotatably

connected to one another; the first member comprising a body and two flanges extending radially from a longitudinal axis of the body; and the second member being located between and retained connected to the first member by said two flanges; wherein one of said flanges is secured to the body by means of a releasable connection; characterized in that said releasable connection constrains relative movement between the body and said one flange so that said one flange is releasable from the body only in a generally radial direction from the longitudinal axis of the body.
2. A swivel joint as claimed in Claim 1, wherein said releasable connection comprises a surface on the body of the first member, which surface extends radially for engagement with said one flange and generally faces the other of said flanges.
3. A swivel joint as claimed in Claim 2, wherein said surface on the body defines part of a recess in the body.
4. A swivel joint as claimed in Claim 3, wherein said recess defines a flat face lying in a plane parallel to and radially offset from the longitudinal axis ofthe body. I
5. A swivel joint as claimed in any of Claims 2 to 4, wherein said surface on the body lies in a plane extending perpendicularly to the longitudinal axis of the body. I
6. A swivel joint as claimed in any of the preceding claims, wherein said one flange comprises a planar member having a slot defined by two spaced apart edges which face each other.
7. A swivel joint as claimed in Claim 6, wherein said spaced apart edges are parallel to each other.
8. A swivel joint as claimed in Claim 6 or 7 when dependent on any of claims 2 to 5, wherein said edges are spaced by a distance substantially equal to the radial thickness of t - 9 - the body portion located immediately adjacent said surface on the body and located between said surface and the other of said flanges.
9. A playground attraction comprising a swivel joint as claimed in any of the preceding claims.
10. A playground swing comprising a swivel joint as claimed in any of Claims 1 to 8.