GB2099693A - Improvements in or relating to castors - Google Patents

Abstract

The castor incorporates a wheel 10 mounted on an axle 11, which axle is connected to two plates 25, 26 depending on either side of the wheel from a support plate 24 mounted above the wheel. A stem 35 is rotatably connected to the support plate. A base plate 13 includes upstanding plates 14, 15 which are pivotally mounted to the axle, the base being capable of assuming a lower position whereby the base provides support, or of assuming an upper position whereby the wheel provides support. A braking lever 47 includes cam plates 41, 42 having cam slots to locate with the axle. Depression of the lever brings the wheel into firm contact with braking bar 40. <IMAGE>

Description

SPECIFICATION Improvements in or relating to castors This invention relates to castors incorporating braking means and particularly although not exclusively to castors for supporting builders' staging. Examples of such castors are described and shown in our prior patents nos. 1 449 292 and 882617.

While these castors have been found to be very effective for mobile towers, some static structures may require the use of base plates especially if the structure is erected on sloping ground. At present either separate castor or base plate assemblies are used.

According to the present invention we provide a castor comprising a wheel, an axle extending through the wheel, brake means capable of applying a brake to the wheel, support means connected with the axle and disposed above the wheel to serve for connection to a load to be supported; the castor also including a rigid base connected with the axle and capable of rotation about the axle to assume, on the one hand a lower position whereby the base rests on a supporting medium, or on the other hand an upper position whereby the wheel rests on the supporting medium; the support means remaining above the wheel in both positions.

In one example the castor includes two plates on opposite sides of the wheel through which the axle passes to permit relative pivotal movement into said positions.

This example may be so constructed that the support means includes a plate disposed horizontally over the wheel and having depending brake plates on opposite sides of the wheel and each having a slot through which the axle passes, and the braking means includes a pair of cam plates having cam slots therein through which the axle passes, said cam plates projecting and being connected together to form a brake operating lever, said brake plates carrying a bar which can be moved to engage the wheel by actuation of said lever.

The invention will be further described by way of example with reference to the accompanying diagrammatic drawings wherein: Figure 1 is an elevational view of a castor made in accordance with the invention with the base plate seating on the ground.

Figure 2 is a view thereof with the wheel on the ground.

Figure 3 is a view at right angles to figure 1.

Figure 4 is an elevational view of a castor made in accordance with the invention with the base plate seating on sloping ground.

Figure 5A is an elevational view of the castor including spring means.

Figure 5B is an elevational view of the castor including spring means holding the base in its upper position.

A wheel 10 is located rotatably on an axle 11.

A base plate 13 rigidly carries two upstanding plates 14, 1 5 located on opposite sides of the wheel. The plates 14, 1 5 have slots 1 6 therein and the axle 11 is extended on both sides of the wheel to pass through the slots 1 6.

A bolt 20 passes through the axle 11 and receives nut 1 9.

A support plate 24 located horizontally above the wheel has two depending plates 25, 26 located on opposite sides of the wheel 10 and these plates are provided with slots through which the axle passes. A rotary plate 28 is mounted by bail bearings on the plate 24 and has a bolt 30 which passes through the plate 24 and a washer 31 and receives a nut 32 on its threaded end. The bolt 30 also passes through the base of a nut 34.

A leg member 35 screws into the nut 34 and carries means to support an upright 36 of a builders' staging.

Braking means comprise a braking bar 40 carried by the plates 25, 26 and cam plates 41, 42 which have cam slots therein through which the axle 11 passes. The cam plates 41,42 have projections at 47 which are connected together by a bar 50 to form a brake actuating lever.

The slots in the plates 25, 26 and 41, 42 are made as described in the prior specifications so that by depressing the braking lever the wheel 10 is brought firmly into contact with the braking bar 10.

The base 13, 14, 1 5 can be moved relatively to the wheel and the plates 25, 26, 41,42 to seat the base on the ground as in figures 1 and 3 or to bring the wheel on to the ground as shown in figure 2. In the position shown in figure 2 the base may be held in its upper position by any suitable device 51.

An example of a suitable device for holding the base in its upper position is illustrated in figure 5A and 5B. A spring 65 is wrapped around axle 11 between upstanding plate 14 and depending plate 25. One spring end is arranged to engage with a slot 61 cut in the plate 14 and the other spring end is slidably located under a bridge 70 fixed onto depending plate 25. Consequently the base 13, 14, 1 5 is urged to rotate in an anti-clockwise direction. However it is restrained from rotation by a cusp 62, which engages with device 51 acting as a stop.

When it is desired to use the wheel the brake lever is raised, the resulting cam action moves device 51 relative to the cusp 62 and allows the base to rotate to its upper position as a result of spring 65, whereupon the brake lever can be depressed to bring the wheel firmly into contact with the brake bar 40. Consequently the addition of spring 65 automatically transfers the base to its upper position and holds it there when use of the base is no longer required. It will be apparent that a second spring may be used between upstanding plate 1 5 and depending plate 26.

An important feature of this invention IS that in the braked position shown in figure 1 the braking bar 40 is firmly engaged on the wheel and the wheel is firmly engaged on the base plate 1 3 and in the position shown in figure 2 the braking bar 40 is firmly engaged on the wheel while the wheel is seated on the ground.

Another important feature is that as shown in figure 4 the invention allows for a structure to be erected on uneven ground.

Claims (6)

1. A castor comprising a wheel, an axle extending through the wheel, brake means capable of applying a brake to the wheel, support means connected with the axle and disposed above the wheel to serve for connection to a load to be supported; the castor also including a rigid base connected with the axle and capable of rotation about the axle to assume, on the one hand a lower position whereby the base rests on a supporting medium, or on the other hand an upper position whereby the wheel rests on the supporting medium; the support means remaining above the wheel in both positions.

2. A castor according to claim 1 , wherein there is included means capable of holding the base in said upper position.

3. A castor according to claim 1 or claim 2, wherein the base includes plate side members extending from the base and pivotally mounted to the axle.

4. A castor according to any one of claims 1, 2 or 3, wherein the support means includes support plates extending from the support means and connected with the axle.

5. A castor according to any preceding claim, wherein the brake means includes cam plates connected with the axle and pivotally mounted to said support plates, the cam plates extending to form a brake operating lever, operation of the lever urging the wheel towards a braking bar carried by said support plates.

6. A castor substantially as herein described with reference to and as illustrated in the accompanying drawings.