WO1998030429A1

WO1998030429A1 - A wheel and brake assembly

Info

Publication number: WO1998030429A1
Application number: PCT/AU1998/000003
Authority: WO
Inventors: Robert Charles Wilson
Original assignee: Wilson Services Pty. Ltd.
Priority date: 1997-01-07
Filing date: 1998-01-02
Publication date: 1998-07-16
Also published as: AUPO446897A0; GB2335012B; NZ336374A; GB2335012A; GB9914368D0

Abstract

A combined wheel and brake assembly for shopping trolleys, etc. of the type where a stationary brake member is sandwiched between two freely rotating wheel discs (16, 17-the drawings show the assembly in end view). When the trolley enters a ramp escalator the discs (16, 17) fall between the escalator ribs (42, 46, 47) bringing the brake area (25) into contact with the escalator. The weight of the trolley forces apart the resilient ribs (40, 41) of the brake member which grip rib (42) of the escalator and prevent movement of the trolley.

Description

TITLE

A WHEEL AND BRAKE ASSEMBLY

FIELD OF THE INVENTION

This invention relates to a braking system for trolley wheels. It is primarily concerned with the braking of shopping trolley wheels travelling on ramp escalators. The invention will be described by way of example with reference to the braking of shopping trolleys travelling on ramp escalators. However, it should be appreciated that this is given by way of example only and that the invention may be applicable to baby carriages and other wheeled devices which may travel on ramp escalators.

BACKGROUND ART

In most shopping centres, travel between floors involves the use of an escalator. The traditional escalators use a moving staircase to transport people from one level to the next. For obvious reasons this type of escalator is not practical for use with shopping trolleys. Therefore, most new shopping centres are employing ramp escalators.

Ramp escalators have an inclined moving ground surface made up of a series of steel panels which are hinged to each other. The panels have an array of parallel longitudinal grooves extending along the panel in the direction of travel. Metal combs which mate with the longitudinal grooves are located at each end of the ramp escalator. The combs prevents debris from entering the internal structure of the ramp escalator.

Such ramp escalators are satisfactory for conveying people but are not satisfactory for wheeled vehicles such as shopping trolleys. When a person with a shopping trolley travels on the ramp escalator the trolley needs to be securely held to prevent it from experiencing unwanted movement. For this reason some trolleys are provided with a braking mechanism.

One type of braking mechanism which has not achieved commercial success is a handle bar brake which is not dissimilar to the brakes found on bicycles. These brakes are however expensive and the connecting wires tend to fray and snag. A type of trolley wheel brake which has achieved a measure of commercial success has a metal strut bolted to the trolley wheel axle. The strut has a downward extending portion which terminates in a flat brake shoe. The brake shoe is fairly small, this being necessary to minimise the brake and strut being tripped over, kicked or scraped against. The brake shoe is spaced above the rim of the wheel such that when the wheel rolls along a level ground surface, the brake shoe does not engage with the ground. The wheel itself is formed from a pair of spaced apart discs defining a channel therebetween. The discs pass into the longitudinal grooves on the ramp escalator and as the grooves are fairly deep, the discs move into the grooves which in turn causes the brake shoe to contact the top of the escalator, thereby braking the trolley wheel.

In practice, an average shopping trolley weights 28kg when empty, and can weigh over 100kg when loaded, and often additionally contains children.

In practice, it is found that the brake shoe is not sufficiently large enough and cannot function effectively to stabilise the trolley. The trolley therefore still slides or moves down the inclined ramp escalator, and as the wheels are formed from pairs of spaced apart relatively thin walled discs, the trolley is also susceptible to tipping.

The channel between the spaced apart discs is sized such that the base wall of the channel does not contact the ramp escalator, as damage to the channel may result if this is allowed to occur.

Another type of known braking system also employs a pair of spaced apart end discs and an intermediate brake member which has a polygonal shape, the shape typically being octagonal. The intermediate member is clamped or otherwise fastened between the end discs and thus rotates with the wheel. While the polygonal member does present level braking surfaces, because it rotates, there is also a high probability that a corner of the intermediate member, rather than a level portion will engage with the ramp escalator, the corner of course having a much smaller braking surface. This can cause the shopping trolley to suddenly move backward or forward which is extremely undesirable. Another disadvantage with current trolley wheels which may or may not have brakes is that the wheels are mostly of the caster wheel type. The caster wheel has an inverted U-shaped bracket which supports an axle on which the wheel rotates. The top of the U-shaped bracket has a socket or a pin which allows the arrangement to be swivably attached to the shopping trolley or other article. Under rough handling conditions, for instance when a trolley is pushed into a gutter or hit by a vehicle, it is common for the swivel pin to bend. This in turn causes the entire wheel to adopt an inclined angle rather than a vertical position. When such a damaged wheel goes on a ramp escalator, the spaced apart discs do not pass into the longitudinal grooves on the escalator and thus the trolley is not properly braked.

Yet another disadvantage with existing braked shopping trolley wheels is that they are effective only when fitted as front wheels. Fitting existing braked wheels as rear wheels is found to not hold a loaded trolley sufficiently. Because of the possibility of wheel damage, shopping trolleys need to be inspected regularly, and typically six month inspections are held. A further disadvantage with existing trolleys having braked wheels is that the assemblies are rather complex to assemble and disassemble.

OBJECT OF THE INVENTION It is therefore an object of this invention to provided a shopping trolley braking system that may overcome the above disadvantages or provide the consumer with a useful or commercial choice.

In one form, the invention resides in a combined wheel and brake assembly for a wheeled apparatus which has need to move onto a grooved ramp escalator, the assembly having a brake member adapted to contact the surface of the grooved ramp escalator when the wheel is positioned on the escalator, the brake member having an escalator engaging portion comprising at least one pair of spaced apart resilient gripping fingers, the spacing between the fingers allowing a rib on the escalator to pass between the fingers and be gripped by the fingers to hold the wheel onto the escalator.

The assembly can be used on shopping trolleys, perambulators and other devices which move onto a grooved ramp escalator.

The brake member can have a substantially flat escalator engaging portion which is formed with a groove, slot, channel or similar recess, with the walls of the recess defining the fingers. The portion, and suitable the entire brake member can be formed from suitable brake material which can include wear resistant plastics such as polyurethanes; rubbers and the like. As the ramp escalator is grooved and thereby consists of a number of parallel ribs, the escalator engaging portion on the brake member may be configured to have adjacent ribs assist in the gripping action of the fingers.

In one form this can be achieved by having the fingers bevelled adjacent an outer portion such that when the fingers extend about a said rib on the escalator, the immediate adjacent ribs push against the bevelled portion to force the fingers into increased gripping contact about the said rib. The assembly may be of the type with the wheel comprising a pair of spaced apart rotatable circular end discs, and an intermediate brake member of the type described above and positioned between the end discs, the brake member having a generally horizontal brake contact area which is spaced inwardly from the rims of the end discs by a distance which allows the wheel to rotate freely over a smooth ground surface but which will engage with the surface of a ramp conveyor when the end discs pass into the longitudinal grooves of the conveyor, the brake member being fixed against rotation relative to the end discs.

The wheel may enable the shopping trolley to move freely on a flat solid ground surface. A shopping trolley wheel mounting may be used to mount the wheel for rotation. The discs may be constructed from any material, with preferred materials being hard and wear resistant. The wheel may be constructed of plastics material. Suitable plastics materials include most engineering plastics, such as polyurethane.

The wheel may be manufactured so that it is integrally formed. Alternatively, the wheel may be constructed through the use of two discs. These discs may be identically shaped and sandwiched together to form the wheel. The discs may each have a circumferentially extending flange or nm The circumferentially extending flange or nm may be of a size that enables them to readily locate within longitudinal grooves on the ramp escalator

An inner axial projection may extend from one side of the circumferentially extending flange An outer axial projection may extend from the opposite side of the circumferentially extending flange The outer axial projection may be associated with radially extending strengthening ribs to reduce flexing of the disc The outer axial projection may be substantially smaller than the inner axial projection The inner axial projection may have a axial groove located in its face to form a corresponding node which is of similar size, shape and orientation to the outer axial projection Each disc may have a hole positioned through its centre adapt to receive an axle The discs may be sandwiched together so that the inner axial projections contact each other, forming a wheel with transversely spaced circumferentially extending flanges The brake member may be constructed so that it is one piece The brake member may have a hole extending through it This hole may be used to locate the brake member between the circumferentially extending flanges of the wheel The brake member may be symmetrical

The brake member may be able to be held in its desired orientation by the shopping trolley mounting member which may be of an inverted U-shaped configuration The brake member may be held by the top of the shopping trolley mounting member Part of the brake member may be used as protection for the wheel Typically, the brake member has a forward portion that is positioned forward of the wheel when the shopping trolley is a forward motion is used as protection This part of brake member may extend outwardly from the circumferentially extending flanges, acting as a form of bumper bar This may reduce the incidence of misalignment of the wheels caused by damage to the wheel

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention will be described with reference to the accompanying drawings in which Figure 1 is a side view of a braking system attached to a shopping trolley wheel mounting.

Figure 2 is a front view of the braking system of Figure 1. Figure 3 is an exploded view of a braking system of Figures 1 and 2.

Figure 4 is a close up view of the escalator engaging portion of the brake member showing the gripping fingers.

Figure 5 shows the brake member of Figure 4 in a gripping position. Figures 6 and 7 illustrate embodiments of the invention with additional brakes.

BEST MODE Figures 1 and 2 show a caster shopping trolley wheel mounting 10 to which a combined wheel and brake assembly 11 has been attached. The shopping trolley mounting 10 has an inverted U-shape and has a fork with two downwardly forwardly spaced apart tines 12. Located between the tines 12 is assembly 11. The assembly comprises a central brake member 14 and a wheel formed from two spaced apart discs 16,17.

Referring to Figure 3 it can be seen that the wheel includes two circular end discs 16,17 constructed of a hard, wear resistant, engineering plastic. The discs 16 have a diameter of 125mm. Each disc 16 has a peripheral rim 16A, 17A of a width smaller than the width of the longitudinal grooves located on the grooved ramp escalator.

An outer axial projection 18 is centrally located on one side of each disc 16,17. The outer axial projection 18 is annular and has a series of equally spaced strengthening ribs 18A extending radially outwardly from it. An inner axial projection 19 is centrally located on the other side of each disc. The inner axial projection 19 is circular. The inner axial projection 19 has a diameter of 75mm and a width of 10mm. An axial groove 20 is located in the face of the inner axial projection 19. The axial groove 20 has a radial spacing of 10mm and a depth of 5mm. A corresponding node 21 is encompassed by this axial groove 20 and has the same size, shape and orientation as the outer axial projection 18. A hole 22 is centrally located in the disc with a diameter of 25mm. The hole 22 is able to receive a bearing 23.

To form a wheel, the two discs 16,17 are sandwiched together so that the inner axial projections 19 and corresponding nodes 20 are in contact. Bearing 23 is passed through the holes 22 in both discs 16,17. An axle passes through bearing 23 and is then mounted to the shopping trolley wheel mount through fasteners. The outer axial projections 18 may in some circumstances assist in spacing the discs 16,17 from the tines 13 of the shopping trolley wheel mounting 10.

Figure 3 also shows the brake member 14. The brake member 14 is a unitary piece of moulded polyurethane having weight-reducing voids therein.

Located adjacent the middle of the brake member 14 is a large locating hole 24 which extends through the brake member 14. The locating hole 24 is of slightly larger diameter than the diameter of the inner axial projection 19. The brake member is roughly symmetrical.

The brake member 14 is located, through the use of the locating hole 24, on the inner axial projections 19 of the disc 16. The brake member 14 is held in the correct orientation by the top of the shopping trolley wheel mounting 10 through extending lugs 31 which pass into the mounting 10 to prevent rotation of the brake member. Although Figure 3 illustrates two lugs, further lugs or other types of projections may be provided to firmly hold the brake member against rotation. The brake member 14 is correctly orientated when the brake contact area 25 to be used does not interfere with the movement of the shopping trolley on a flat ground surface. The brake contact area 25 to be used is substantially horizontal with the ground surface and spaced radially inwardly from the peripheral rim of each disc 16,17. The member 14 substantially fills the space between discs 16,17 to support the discs against dents and damage.

In the embodiment, the brake member 14 also operates as a bumper bar for the wheel. The brake member has an upper forward portion 30 which extends outwardly from the rim of the wheel discs. This portion is located in front of the wheel when the shopping trolley is in a forward motion. Any object that the shopping trolley hits, such as a wall or gutter, contacts the brake member not the wheel. Therefore, the wheel is less likely to become misaligned.

The brake system operates when travelling on a ramp escalator. The peripheral rims 16A, 17A locate within the longitudinal slots of the belt of the ramp escalator. The brake contact area 25 contacts the belt of the ramp escalator.

Figures 4 and 5 show a lower part of the brake member. The brake contact area 25 (or escalator engaging portion) has a pair of spaced apart fingers 40,41 which are spaced apart sufficiently to allow a rib 42 of the escalator to be pushed between the fingers. The fingers are resilient and are integrally formed with the brake member 14, and are thus formed of polyurethane (this being only exemplary of a suitable material) The fingers are formed by grooving the bottom face of the brake contact area 25 to form an elongate longitudinal groove or slot 43 having a slot depth of about 5mm. The walls of the slot form the fingers 40, 41.

The outer side of each finger is bevelled at 44, 45 and the function of the bevel is to force the fingers further together about rib 42. Thus, as the brake contacts the escalator, brake contact area 25 is forced onto the escalator ribs by the weight of the trolley. Fingers 40 41 are pushed slightly out as rib 42 is forced into the slot 43. The bevelled wall of each finger contacts the adjacent ribs 46,47 of the escalator and are squeezed towards rib 42 which increases the grip of fingers about rib 42.

When the wheel reaches the end of the escalator, the end discs 16,17 will rise out of the grooves and will pull the brake member out of engagement with the ribs. The bevels 44,45 assist in removal of the brake member from the rib by progressively decreasing the grip action on rib 42 as the brake member is lifted upwards.

A further advantage with this arrangement is that the wheel and brake assembly comprises only three components being the two wheel discs and the single central polyurethane brake member. The wheel assembly can therefore be readily removed and opened for repair, cleaning or replacement.

Figures 6 and 7 illustrate variations of the invention. Figure 6 illustrates a triple braking system. In this figure, a pair of additional brakes 50,51 are bolted to the axle of the main wheel assembly. Brakes 50,51 have lower polyurethane blocks 52,53 which are formed with slots 54,55 identical to slot 43.

Figure 7 illustrates a variation where the central wheel assembly is not provided with a slot, but the external brakes 50,51 are. Figure 7 can therefore be seen as an external braking system having one or two external brakes 50,51. The advantage of the system of Figures 6 and 7 is that it is relatively easy to bolt on the external brakes which will improve the braking ability of the shopping trolley (or other device).

It should be appreciated that various modifications may be made to the embodiment described without departing from the spirit and scope of the invention.

Claims

CLAIMS:

1. A combined wheel and brake assembly for a wheeled apparatus which has need to move onto a grooved ramp escalator, the assembly having a brake member adapted to contact the surface of the grooved ramp escalator when the wheel is positioned on the escalator, the brake member having an escalator engaging portion comprising at least one pair of spaced apart resilient gripping fingers, the spacing between the fingers allowing a rib on the escalator to pass between the fingers and be gripped by the fingers to hold the wheel onto the escalator.

2. The assembly of claim 1 , wherein the brake member has a substantially flat escalator engaging portion which is formed with a groove, slot, channel or similar recess into which a rib of the ramp escalator can pass with the walls of the recess defining the fingers.

3. The assembly of claim 2, wherein the fingers are configured such that adjacent ribs of the ramp escalator assist in the gripping action.

4. The assembly of claim 3, wherein the fingers are beveled adjacent an outer portion such that when the fingers extend about a said rib on the escalator, the immediate adjacent ribs push against the beveled portion to force the fingers into increased gripping contact about the said rib.

5. The assembly of claim 1 wherein the wheel is formed from a pair of spaced apart wheel discs, the discs having a peripheral rim which can pass into the grooves of the ramp escalator.

6. The assembly of claim 5, wherein the escalator engaging portion is spaced inwardly from the peripheral rim of the wheel discs.

7. The assembly of claim 5, wherein the brake member is positioned between the wheel discs.

8. The assembly of claim 1 , wherein the brake member is on the outside of the wheel.

9. The assembly of claim 1 , comprising a plurality of the brake members.

10. The assembly of claim 1 comprising a shopping trolley wheel.