BACKGROUND OF THE INVENTION Many shopping centers now use inclined moving ramp walkways to convey shoppers between floors. These escalators comprise a series of linked moving panels which are grooved in the direction of travel. Typical approximate cross- sections and dimensions of panels as produced by some of the major manufacturers are shown in figures 1A to 1D as follows: Figure 1A Boral Profile A = 2.75 mm B = 8.50 mm Figure 1B Kone Profile A = 2.90 mm B = 9.00 mm Figure 1C Otis Profile A = 2.50 mm B = 8.46 mm Figure 1D Schindler Profile A = 2.57 mm B = 9.06 mm While the spacing and width of the grooves 1 defined between the longitudinal ribs 2 vary between manufacturers the ramp surfaces are nevertheless of basically similar design. To enable loaded shopping trolleys to use these ramp escalators it is known to provide the trolleys with a plurality of wheels formed with peripheral rails at the inner and outer faces. A channel is thereby defined between the rails. A downwardly directed brake shoe is also fixed out to one side of the wheel fork or castor and slightly above floor level when the trolley is on a flat surface.

While the wheels operate without hindrance in the store, as they are moved onto a ramp escalator the ridges sink into the grooves 1 so that the fixed brake shoe then engages the tops of the ribs 2. The trolley is thereby restrained to some degree against unwanted movement down the incline of the ramp.

In practice however the frictional braking force exerted by existing brake shoes which are typically flat is often inadequate and the trolley still has to be held.

SUMMARY OF THE INVENTION It is therefore an object of this invention to ameliorate the aforementioned disadvantage and accordingly a brake apparatus is disclosed for a shopping trolley of the type having a wheel with peripheral rail means which when said wheel is placed onto a moving ramp walkway having grooves defined between longitudinal ribs drop down into said grooves, said brake apparatus including a bracket which mounts a brake shoe having one or more fingers, said bracket being adapted for attachment adjacent said wheel whereby in use of said shopping trolley on a flat floor surface said brake shoe is clear and inoperative but when placed onto said moving ramp walkway said one or more fingers wedge down between adjacent ribs to inhibit movement of said shopping trolley.

BRIEF DESCRIPTION OF THE DRAWINGS The currently preferred embodiment of this invention will now be described with reference to the attached drawings in which:- Figure 2 is a perspective view of a first embodiment of a brake apparatus according to this concept, Figure 3 is a cross-sectional view along the lines A-A of figure 2, and Figures 4 to 6 show side, end and perspective views of a second embodiment of the brake apparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to figure 1 there is a wheel 3 of the type normally fitted to the rear and/or front of shopping trolleys. The wheel yoke 4 may be pivoted around a vertical axis 5 to allow the trolley to be steered and the wheel itself rotates about a horizontal axle 6. Also, in accordance with known design the wheel comprises a pair of spaced apart peripheral rails 3A and 3B which define a central channel 3C. The rails are shaped and spaced to drop down into the aforementioned grooves 1 of a ramp escalator under the weight of the trolley.

Although with this embodiment the brake member 7 is shown as secured to the wheel yoke 4 by means of a steel bracket plate 8 and nut 9 turned onto the axle 6 the invention is not limited to this. The bracket plate 8 also preferably includes a tab 8A which protrudes out into a corresponding aperture in the wheel yoke to prevent the brake member pivoting about the axle 6. It extends to any other suitable fastening arrangement which secures the brake shoe 10 at an operative position relative to the wheel 3.

When the wheel passes over a solid flat surface such as a shop floor the shoe 10 is positioned above and clear of said surface and the brake is therefore inoperative.

However, upon placement of the trolley onto the grooved surface of a ramp escalator of the type shown or similar to figures 1A to 1D the ridges 3A and 3B sink down into the grooves 1 sufficiently that the finger 10A of the brake shoe also drops down between adjacent ribs. By virtue of the tapered shape of this finger as best shown in figure 3 and the resiliency of the material from which it is made a wedging action takes place. Considerable frictional forces are thus generated between the sides of the finger and the edges 2A of the ribs (shown by broken lines in figure 3).

The wheel 3 is thereby more effectively locked against movement than with most conventional flat brake shoes which merely sit on the upper surface of the ribs 2.

The leading and/or trailing edges of the fingers 10C and 10D may also be radiused or rounded as shown.

Although the invention at this stage is not limited to any specific shape, configuration or dimensions for the brake shoe the finger is preferably about 11 mm wide at the base B, 4 mm wide at the tip C and about 13 mm in height D which produces an inward taper in the downward direction of between 70 to 80 degrees. With this particular embodiment a longitudinal aperture 10B has also been formed in the finger to facilitate lateral deformation as it wedges between the ribs. It is further preferred that the shoe be moulded from Polyurethane although the invention extends to the use of any other suitable material.

With the second embodiment shown in figures 4 to 6 the operation of the brake is basically the same. In this case however the shoe 11 is solid and has no longitudinal aperture. While the shoe 11 is shown as being secured to the bracket plate 12 by means of a rivet 13 the attachment may alternatively be obtained by moulding the shoe around the plate.