GB2133996A - Speed restrictor for children's roundabouts - Google Patents

Abstract

The roundabout is provided with a speed damper to prevent the roundabout from being propelled above a predetermined speed. The damper includes two sets of contra rotating blades 50, 72, gear rings 54, 62 and intermediary pinions 56, all located in a drum containing oil which acts as a damping medium. <IMAGE>

Description

SPECIFICATION Improvements relating to roundabouts This invention relates to playground roundabouts and in particular to the control of the speed of such roundabouts.

Roundabouts are, as is well known, devices which comprise a framework which is rotatable about a vertical axis, and the function of a roundabout is to provide amusement and entertainment for children who derive such pleasure by riding on the roundabout. A problem with roundabouts is that they can be dangerous if they are rotated too rapidly and children can be harmed if propelled from the roundabout by the high centrifugal force which can be generated when the roundabout is rotated too rapidly.

Younger children are unable to rotate the roundabouts too rapidly because of their mass, but older and irresponsible children can and do propel roundabouts at frightening speed.

This invention aims to overcome this disadvantage of roundabouts, and in accordance with the invention there is provided a children's roundabout which is provided with a speed restrictor device which limits the speed of rotation of the roundabout to a predetermined maximum.

Preferably, the speed restrictor is a hydraulic damper comprising first and second relatively rotatable vanes or blades and a quantity of hydraulic fluid between the blades so as to be displaced between the blades and form damping means.

The first and second blades preferably are rotatable in opposite directions about the same axis, the second set of blades being at a larger radius than the first set of blades.

The first and second set of blades may be geared so as to rotate in synchronism, and they are drivingly connected to the roundabout platform or decking which supports the passengers so as to be driven thereby.

The speed restrictor may comprise a drum containing the hydraulic fluid, and the second set of blades may be fast with the inside of the drum, whilst the first set of blades may be connected to a spindle located centrally of the drum, both sets of blades lying in radial planes.

There may be the same number of blades in each set, or there may be more blades in one set than in the other, the actual number of blades in either set is not important, provided there are enough to achieve the desired result.

In an alternative arrangement, one set of the blades may be stationary.

The damper may be drivable by the platform directly or through gearing.

In order that the invention may be more readily understood, embodiments thereof will now be described, by way of example, reference being made to the accompanying drawings, in which: Figure 1 is a front sectional elevation of part of a movable, rotatable member incorporating a speed control device according to the invention; Figure 2 is a plan view on part of Figure 1; Figure 3 is a sectional view similar to fig. 1, but showing an alternative embodiment of the invention; and Figure 4 is a sectional plan of the device shown in fig. 3.

Referring to figs. 1 and 20f the drawings, a rotatable member, indicated generally by reference numeral 2, is mounted for rotation relative to a centre post 4 to which is attached, as by welding, an oil bath 6 containing oil to a level indicated by reference numeral 8.

The rotatable member, which is part of a playground roundabout, comprises a central member 10 mounted to a shaft 12 such that it is rotatable therewith, in bearings on a member 14 located in the centre post 4 such that the member 2 including the central member 10 and bearings, may rotate relative to said centre post.

Extending radially from the central member 10 are support arms 1 6 and 1 8 to which are secured planar members (not shown) to provide a platform on which users of the roundabout may locate themselves.

Projecting downwardly from the underside of the support arms 18 are four vanes or arms 20, 22, 24 and 26 which are in the form of elongate plates and which are secured, as by welding, to the underside of the support arms 1 8 so as to be rotatable with said arms when the arms rotate relative to the centre post 4. As will be seen, a major portion of each vane or arm 20, 22, 24 and 26 lies within the oil in the oil bath 6. The vanes or arms 20, 22, 24 and 26 are located at 900 intervals around the centre post 4.

Attached to and projecting outwardly from the centre post 4 are three vanes or arms 28, 30, and 32, which are fixed to the centre posts and are thus non-rotatable. As will be seen from Figure 2, the fixed vanes or arms 28, 30, and 32 are located at 1200 intervals relative to the centre post 4, such that at any one time only one each of the vanes or arms 20 to 26 and 28 to 32 are in coincidence. Figure 2 shows vanes or arms 20 and 28 in coincidence.

To prevent ingress of foreign objects to, and possible tampering with, the speed control device of the invention, a skirt 24 may be welded to the underside of the arms 18, as shown in Figure 1.

The oil bath 6 will preferably be provided with a tapped hole 36 to which may be fitted a valve (not shown) for draining the oil from the bath 6. In an alternative arrangement, where the oil bath 6 is set below ground level, an extension tube may extend upwardly on the outside of the bath and have a valve fitted to its upper end. In this case, oil would be drawn from the bath 6 by means of a suction pump, not shown.

In use, it will be appreciated that as the support arms rotate relative to the centre post 4, the vanes or arms 20, 22, 24 and 26 will move through the oil in the oil bath 6. Such movement of these arms through the oil would, but for the presence of the fixed vanes or arms 28, 30 and 32, cause rotation of the oil within the bath 6. However, the fixed vanes or arms 28, 30 and 32 effectively prevent rotation of the oil by providing a turbulence or blocking effect such that the effect of rotating the arms 20, 22, 24 and 26 is cancelled out. Thus the speed of the rotating support arms 1 6, 18 and hence the speed of the roundabout as a whole, is effectively restricted so as to reduce the momentum of the roundabout.

Should it be found that the retarding force provided by the fixed vanes is too great, so as to severely restrict the speed of rotation of the roundabout, holes may be drilled in the rotating vanes or arms, or the rotating vanes or arms could be shortened slightly. On the other hand should the retarding force be too small, the movable vanes or arms could be increased in width in order to reduce the clearance between the movable and the fixed vanes or arms and/or the number of movable vanes or arms could be increased. In addition, oils of different viscosities may be used to effect further control of the speed of rotation of the roundabout.

In the embodiment of figs. 3 and 4, the arrangement is similar to that shown in figs. 1 and 2, except that the rotatable platform which carries the passengers has a plurality of downwardly extending rods 40, which engage in slots 41 of a gear wheel 42 fast with a short shaft 44. Shaft 44 is rotatable about a vertical axis 46 which is offset relative to the axis of rotation of the support platform but parallel thereto.

To the shaft 46 is welded an inverted drum 48 and to the inside of the drum 48 are radial blades or vanes 50 (4 provided in this example).

At this lower end, the drum 46 has an annulus 52 having on its inner side teeth 54, and these teeth 54 are engaged by four equi-angularly spaced pinions 56 which are positionallyfixed relative to but rotatable on the base plate 58 of an oil drum 60 which contains the oil forming the damping fluid.

The pinions 56 engage teeth 62 on the outer edge of a toothed plate 64 which is fast with a rotatable cylinder 66 supported by bearings 68, 70 for rotation independently of the drum 60. The cylinder supports radial blades or vanes 72 (4 in this example) as shown which have outer edges 74 which lie in a cylindrical plane which is of less diameter than that of the plane on which the inner edges of the blades 48 lie.

A cover ring 76 serves to prevent spillage of oil from the drum 48 during rotation of the roundabout.

It will be appreciated that as the roundabout is rotated, so the blades 48 and 72 are relatively rotated in opposite directions and this has been shown to be effective in creating such resistance to rotation of the roundabout, by virtue of the driving of the oil across the blades, to ensure that the roundabout does not exceed a predetermined speed as dictated by the geometry of the blades and the oil drum 60 It has also been shown that the resistance to rotation is increased in proportion to a power of the speed, which makes the damping have the correct characteristic for roundabouts.

Claims (8)

1. A children's roundabout which is provided with a speed restrictor device which limits the speed of rotation of the roundabout to a predetermined maximum.

2. A roundabout according to claim 1, wherein the speed restrictor is a hydraulic damper comprising first and second relatively rotatable vanes or blades and a quantity of hydraulic fluid between the blades so as to be displaced between the blades and form damping means.

3. A roundabout according to claim 2, wherein the first and second blades are rotatable in opposite directions about the same axis, the second set of blades being at a larger radius than the first set of blades.

4. A roundabout according to claim 3, wherein the first and second set of blades are geared so as to rotate in synchronism, and they are drivingly connected to the roundabout platform or decking which supports the passengers so as to be driven thereby.

5. A roundabout according to claim 4, wherein the speed restrictor comprises a drum containing the hydraulic fluid, and the second set of blades is fast with the inside of the drum, whilst the first set of blades is connected to a spindle located centrally of the drum, both sets of blades lying in radial planes.

6. A roundabout according to claim 5, wherein there are the same number of blades in each set, or there may be more blades in one set than in the other.

7. A roundabout according to claim 6, wherein the damper is dribble by the platform through gearings so that the damper is offset relative to the support of the roundabout.

8. A roundabout substantially as herein before described with reference to either of the embodiments of the accompanying drawings.