GB2272638A

GB2272638A - Trolley castors

Info

Publication number: GB2272638A
Application number: GB9323953A
Authority: GB
Inventors: Robert Molson; Christopher Molson
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-11-18
Filing date: 1993-11-18
Publication date: 1994-05-25
Also published as: GB9224129D0; GB9323953D0; WO1994011209A1

Abstract

A trolley wheel mounting allows the wheel 10 to swivel freely in one direction on a trunnion 15, but not in the other; a pivoted peg 17 engages the edge of a cam 16, riding over the cam face in one turning direction, but engaging a step on the cam to prevent swivelling in the other direction. The mounting may be provided on both rear wheels of a trolley to improve controllability. <IMAGE>

Description

IMPROVEMENTS IN OR RELATING TO TROLLEYS The present invention relates to a trolley and to a means for steering a trolley and is concerned particularly, although not exclusively, with a shopping trolley and means for steering the same.

Shopping trolleys such as are used in large shops or supermarkets typically comprise a basket for containing shopping and a support frame to which are attached a plurality of wheels. There are commonly four wheels which are located at corners of the frame. Each wheel is able to turn through 360" about a turning axis which is perpendicular to the axis of rotation of the wheel, such that a user may push the trolley in any direction. The turning axis is spaced from the axis of rotation of the wheel so that when the trolley is pushed in any direction the wheel is made to turn about its turning axis until the wheel is rolling in the same direction as that in which the trolley is being pushed such that the centre of the wheel trails behind the turning axis in whatever direction the trolley is pushed.

Since all four of the wheels are able to turn through 3600, the trolley can be pushed in any direction and each wheel will then roll in that direction. When a change of direction is required the user pushes the trolley in the new direction and very quickly each of the wheels turns where necessary so as to roll in the new direction.

A disadvantage with this kind of steering is that when the trolley is laden with shopping it becomes much heavier and it is difficult to make the trolley turn around a corner in such a way that the front of the trolley turns the corner first and the rear follows the front. Turning in this way is desirable since the handle of the trolley, with which the trolley is pushed in use, is located on only one side of the trolley (usually the rear) and so the user must remain positioned on this side of the trolley. The difficulty arises because each of the four wheels are able to roll in the direction in which the trolley is being pushed at any instant.Therefore unless the user continuously changes the direction in which the trolley is pushed the trolley will tend to move sideways or at least tangentially with respect to the corner so that its rear no longer follows its front around the corner. Correcting this tendency is difficult because of the weight of the laden trolley and attempting to do so, particularly in a hurry, can lead to accidents and even injury to the user.

According to a first aspect of the present invention there is provided a trolley having a plurality of wheels, at least some of which are able to turn about turning axes which turning axes are transverse to the respective axes of rotation of the wheels, wherein at least one of the wheels is provided with restricting means arranged to restrict the turning of said wheel about its turning axis in at least one direction.

The turning axis may be substantially perpendicular to the respective axis of rotation of the wheels.

Preferably the restricting means is arranged to permit unrestricted turning of the wheel in a first direction and to prevent turning of the wheel beyond a predetermined extent in a second direction opposed to the first direction.

In a preferred arrangement the restricting means is arranged to prevent turning of the wheel in the second direction beyond a position corresponding to a straight ahead direction of the trolley in use.

Preferably the trolley comprises first and second wheels, each having a restricting means, wherein the restricting means of the first wheel is arranged to restrict turning of the first wheel only in a first direction and the restricting means of the second wheel is arranged to restrict turning of the second wheel only in a second direction, which second direction is opposed to the first direction.

In a preferred arrangement the first and second wheels are located on left and right sides of the trolley respectively. Preferably the first and second wheels are arranged at the rear of the trolley in use.

The trolley may comprise at least one front wheel and first and second rear wheels, the arrangement being such that the or each front wheel is permitted to turn without restriction in either of two opposed directions and the rear wheels are each allowed to turn without restriction in one direction and are prevented from turning beyond a respective predetermined extent in another, opposed direction each by its respective restricting means, wherein the direction in which the first rear wheel is prevented from turning beyond its predetermined extent is opposed to that direction in which the second rear wheel is prevented from turning beyond its predetermined extent.

Preferably when both of the first and second wheels are turned as far as their respective predetermined extent, the first and second rear wheels are substantially parallel.

The arrangement may be such that when the moving trolley is made to turn in a desired direction the or each front wheel and one of the first and second rear wheels are arranged to turn towards the desired direction and the other of the first and second rear wheels is arranged to remain in an orientation which substantially corresponds to a straight ahead direction of the trolley in use.

The trolley may comprise a frame on which one or more of the wheels may be mounted.

Preferably the straight ahead direction of the moving trolley is substantially parallel to a longitudinal axis of the trolley.

Preferably the or each restricting means is moveable between a first operative configuration in which it is arranged to restrict the turning of the wheel and a second, inoperative configuration in which it is arranged not to restrict the turning of the wheel.

In a preferred arrangement the restricting means is arranged in use to move from the first configuration to the second configuration by cooperation of a portion of the restricting means with a second trolley.

The restricting means may be arranged in use to move from the first configuration to the second configuration by co-operation of a portion of the restricting means with a disabling member of a second trolley.

The disabling member may be attached to a second trolley. Alternatively or additionally, the disabling member may be integral with a second trolley.

There may be provided two disabling members, arranged in use to cause movement of respective restricting means of respective wheels of a trolley.

Preferably, the or each disabling member comprises an arm arranged in use to co-operate with a restricting means.

In a preferred arrangement the restricting means comprises an abutment member arranged in use to abut an abutment portion of a turning member which turning member is arranged in use to turn with the wheel.

The turning member may be arranged to turn with the wheel in a second direction until a portion of the turning member abuts the abutment member.

The turning member may comprise a plate member.

The turning member may comprise a cam surface against which the abutment member is arranged to bear during turning of the wheel.

Preferably the abutment member is arranged to move between a first operative configuration in which it is arranged to abut the turning member and a second inoperative configuration in which it is arranged not to abut the turning member.

In a preferred arrangement the abutment member is arranged to move pivotally between the first and second configurations.

According to a second aspect of the present invention there is provided restricting means to restrict the turning of at least one wheel of a trolley about a turning axis of that wheel which turning axis is transverse to an axis of rotation of the wheel, wherein the restricting means is arranged to permit unrestricted turning of the wheel in a first direction and to prevent turning of the wheel beyond a predetermined extent in a second direction opposed to the first direction.

Preferably, the turning axis is substantially perpendicular to the axis of rotation of the wheel.

The restricting means may be according to any statement herein.

According to a third aspect of the present invention there is provided guide means for aligning a tool with a portion of a trolley frame, wherein the guide means comprises a first portion arranged to engage a portion of the frame of the trolley and a second portion connected to the first portion which second portion includes means arranged in use to guide a drill bit to work on the frame at a predetermined location.

Preferably the second portion comprises a tube arranged in use to guide a drill bit to make a hole at a predetermined angle to the frame. The predetermined angle may substantially comprise a right-angle.

According to a fourth aspect of the present invention there is provided a method of steering a trolley, the trolley comprising a plurality of wheels at least one of the wheels being turnable about a turning axis substantially perpendicular to its axis of rotation, the method comprising permitting unrestricted turning of at least one of the wheels in a first direction and preventing turning of that wheel beyond a substantially predetermined extent in a second direction substantially opposed to the first direction.

The method preferably comprises restricting the turning of one wheel in only a first direction and restricting the turning of a second wheel in only a second direction opposed to the first direction.

The invention includes any combination of the features or limitations referred to herein.

The invention may be carried into practice in various ways but an embodiment will now be described by way of example with reference to the accompanying diagrammatic drawings in which: Figure 1 is a side view of a right hand wheel of a trolley.

Figure 2 is a plan view of the wheel of figure 1, Figure 3 is a schematic view of four wheels of a trolley which trolley is turning to the right, Figure 4 is a schematic view of the four wheels of figure 3, when the trolley is turning to the left, Figure 5 shows a guide tool for assembling the wheel of figures 1 and 2, and Figure 6 shows in more detail a plate for use in a wheel according to an embodiment of the invention.

Referring particularly to figures 1 and 2, they show a rear right sided wheel generally at 10 attached to a frame portion 11 of a supermarket trolley (not shown).

The wheel 10 is one of a pair of two rear wheels 10, 12 (shown schematically in figures 3 and 4). The wheel 10 is attached to the frame 11 via a trunnion 13 on which the wheel is conventionally mounted by means of axle 14.

The trunnion 13 is itself rotatably mounted on a mounting member 15 which is conventionally attached to the frame 11 of the trolley. Hence the trunnion 13 and therefore the wheel 10 are able to turn through 3600 with respect to the frame 11 about a turning axis (not shown) which is concentric with the mounting member 15.

On an upper surface of the trunnion 13 is welded a steel plate 16 which turns with the trunnion 13 and therefore with the wheel 10. The steel plate has arcuate profile surfaces 16a and 16b (shown in figure 2) which meet at a step 16c. A steel abutment peg 17 is pivotally mounted on the frame 11 at 11a such that a lower portion 17a of the peg rests against the edge of the plate 16 in use.

It will be appreciated that when the wheel 10 and therefore the steel plate 16 are turned in a counterclockwise direction, the peg 17 will slide against the edge of the plate 16 and will not restrict the turning of the plate 16. However, if the wheel 10 and plate 16 are turned in a clockwise direction, the peg 17 will slide against the edge of the plate 16 until it reaches the step portion 16c thereof, whereupon it will prevent further turning of the plate 16 and therefore of the wheel 10.

The step portion 16c is arranged parallel with the centre of the wheel 10 and with the frame 11 in such a way that when the peg 17 abuts the step portion 16c of the plate 16 the wheel 10 is parallel with the frame 11 and so tends to run in a direction which corresponds to a straight ahead direction of the trolley in use.

The peg 17 is provided with an upper portion 17b which is engaged by a disabling member (not shown) of another trolley (not shown) when the trolleys are stacked together in the conventional manner such that each trolley is partly inside the trolley in front. The disabling member (not shown) comprises a steel arm which is attached to and extends from a portion of the other trolley.

When the portion 17b of the peg 17 is thus engaged it pivots about pivot 11a and the lower portion 17a becomes released from its contact with the plate 16. The plate 16 and therefore the wheel 10 can then turn freely about the turning axis in either clockwise or counter-clockwise directions.

The arrangement permits the disabling of the peg by another trolley when the trolleys are stacked or "nested" without the need for the co-operation of the peg with a portion of a frame of another trolley. This is particularly important when the trolleys are of an openfronted design without a portion of frame extending across the front of the trolley.

Figure 3 shows schematically, in plan, an arrangement of four wheels 10, 12, 18 and 19 of a trolley (not shown).

Each of the wheels 10, 12, 18 and 19 is mounted in a trunnion which is itself rotatably mounted on the frame 11 of the trolley.

The front wheels 18 and 19 have no plate 16 nor peg 17 and are freely able to turn through 360" in either clockwise or counter-clockwise direction.

However, the rear wheels 10 and 12 are each provided with a plate 16 and peg 17. The right sided wheel 10 is as described above in relation to figures 1 and 2.

However, on the left sided wheel 12 the peg 17 is located on the opposite side of the frame 11 to that of the wheel 10. In addition the plate 16 has its step portion 16c which is arranged in an opposite sense to that shown in figures 1 and 2. The arrangement for the left sided wheel 12 is such that it may turn without restriction in the clockwise direction but when it turns in the counterclockwise direction the peg 17 abuts the step portion 16c of plate 16 to prevent turning of the plate 16 and wheel 12 beyond a position in which the wheel 12 is parallel with the frame 11.

The rear wheels 10 and 12 are therefore each able to turn without restriction in a first direction and are prevented from turning beyond a predetermined extent in a second direction opposed to the first direction and the first and second directions are of opposite senses for the two wheels 10 and 12.

Figure 3 shows the action of the wheels 10, 12, 18 and 19 when the trolley is made to turn right. Front wheels 18 and 19 tend to turn in a direction in which the trolley is being turned. In addition the left hand rear wheel 12 is permitted to turn in the direction in which the trolley is being turned. However, the right hand wheel 10 is unable to turn in this way since the peg 17 abuts the step portion 16c of the plate 16 and thereby prevents turning of the plate 16 and wheel 10 in the clockwise direction beyond the extent shown.

Because the right sided rear wheel 10 is unable to turn with the other wheels, the trolley does not tend to move sideways when it is making a turn. Instead the front part of the trolley makes the turn first and the rear portion follows the front in the desired manner.

Figure 4 shows the arrangement of the wheels 10, 12, 18 and 19 when the trolley (not shown) is being turned to the left. Wheels 10, 18 and 19 tend to turn to the direction in which the trolley is being turned and wheel 12, the left sided rear wheel, remains parallel to the frame 11 by abutment of the plate step portion 16c with the peg 17.

It has been found that a fully laden trolley is easier to turn when its rear wheels are restricted in this way.

It is essential, however, that the pivoting abutment peg 17 be correctly mounted on the frame 11. If the peg 17 is not parallel to the frame 11 the plate 16 will not be abutted by the peg 17 when the wheel faces straight ahead. In addition, the plate 16 must be mounted on the trunnion in such a way that the step portion 16c abuts the peg 17 when the wheel 10 faces straight ahead.

Figure 5 shows a guide tool 20 for enabling the peg 17 to be correctly mounted on the frame 11. The guide tool 20 comprises a steel U-shaped portion 20a, arranged to be a snug fit over the frame 11, and a steel guide tube 20b welded to the U-shaped portion 20a, the bore 20c of which is exactly perpendicular to the extent of the frame 11 when the U-shaped portion 20 is in position. A drill bit (not shown) can then be inserted in the bore 20b to drill a hole in the frame 11. The hole thus drilled, and through which a portion of the peg 17 will pass, is exactly perpendicular to the extent of the frame 11.

After the hole has been formed a mild steel bushing (not shown) is placed therein before the peg 17 is inserted and held in place by an end stop 20 (shown in figure 2). As an alternative to a mild steel bushing a nylon bushing could be used which would avoid problems of corrosion due to the trolley being exposed to wet weather conditions.

Figure 6 shows in more detail the plate 16. In this case the plate is for a left sided wheel of the trolley (not shown). The steel plate 16 is manufactured by stamping it out from a sheet of steel which is preferably approximately 2mm in thickness. To provide protection for the step portion 16c it is folded over itself to make it thicker. This is necessary since this portion of the plate will be frequently abutted by the peg 17 (not shown) which abutment might lead to damage of the plate 16 after repeated use. When the plate 16 is stamped out a small triangular fold-down tab 21 is formed in the plate. This tab 21, when folded down, is used to align the plate on the trunnion (not shown) so that the axis X of the plate is exactly parallel with the centre of the wheel (not shown). This is achieved by folding down the tab 21 and placing it over the shoulder (not shown) of the trunnion 13 (shown in figure 1) in which the wheel is mounted.

The above described invention provides a means of safely steering a supermarket trolley around corners without the trolley tending to move sideways or tangentially with respect to the corner.

New trolleys can be manufactured which feature the invention. Alternatively or additionally existing trolleys can be modified to feature the invention.

Whilst the invention has been described above in relation to a supermarket trolley, it will be understood that it may be employed with other types of wheeled vehicle.

Claims

1. A trolley having a plurality of wheels, at least some of which are able to turn about turning axes which turning axes are transverse to the respective axes of rotation of the wheels wherein at least one of the wheels is provided with restricting means arranged to restrict the turning of said wheel about its turning axis in at least one direction.

2. A trolley according to claim wherein the turning axis is substantially perpendicular to the respective axis of rotation of the wheels.

3. A trolley according to claim 1 or claim 2 wherein the restricting means is arranged to permit unrestricted turning of the wheel in a first direction and to prevent turning of the wheel beyond a predetermined extent in a second direction opposed to the first direction.

4. A trolley according to any of claims 1 to 3 wherein the restricting means is arranged to prevent turning of the wheel in the second direction beyond a position corresponding to a straight ahead direction of the trolley in use.

5. A trolley according to any of claims 1 to 4 wherein the trolley comprises first and second wheels, each having a restricting means, wherein the restricting means of the first wheel is arranged to restrict turning of the first wheel only in a first direction and the restricting means of a second wheel is arranged to restrict turning of the second wheel only in a second direction which second direction is opposed to the first direction.

6. A trolley according to claim 5 wherein the first and second wheels are located on left and right sides of the trolley respectively.

7. A trolley according to claim 5 or 6 wherein the first and second wheels are arranged at the rear of the trolley in use.

8. A trolley according to any of claims 5 to 7 wherein the trolley comprises at least one front wheel and first and second rear wheels, the arrangement being such that the or each front wheel is permitted to turn without restriction in either of two opposed directions and the rear wheels are each allowed to turn without restriction in one direction and are prevented from turning beyond a respective pre-determined extent in another opposed direction, each by its respective restricting means, wherein the direction in which the first rear wheel is prevented from turning beyond its pre-determined extent is opposed to that direction in which the second rear wheel is prevented from turning beyond its pre-determined extent.

9. A trolley according to any of claims 5 to 8 wherein when both of the first and second wheels are turned as far as their respective pre-determined extent, the first and second rear wheels are substantially parallel.

10. A trolley according to any of claims 5 to 9 wherein when the moving trolley is made to turn in a desired direction, the or each front wheel and one of the first and second rear wheels are arranged to turn towards the desired direction and the other of the first and second rear wheels is arranged to remain in an orientation which substantially corresponds to a straight ahead direction of the trolley in use.

11. A trolley according to any of claims 1 to 10 wherein the trolley comprises a frame on which one or more of the wheels is mounted.

12. A trolley according to claim 10 wherein the straight ahead direction of the moving trolley is substantially parallel to a longitudinal axis of the trolley.

13. A trolley according to any of claims 1 to 12 wherein the or each restricting means is moveable between a first operative configuration in which it is arranged to restrict the turning of the wheel, and a second inoperative configuration in which it is arranged not to restrict the turning of the wheel.

14. A trolley according to claim 13 wherein the restricting means is arranged in use to move from the first configuration to the second configuration by cooperation of a portion of the restricting means with a second trolley.

15. A trolley according to claim 13 or claim 14 wherein the restricting means is arranged in use to move from the first configuration to the second configuration by cooperation of a portion of the restricting means with a disabling member of a second trolley.

16. A trolley according to claim 15 wherein the disabling member is attached to a second trolley.

17. A trolley according to claim 15 or 16 wherein the disabling member is integral with a second trolley.

18. A trolley according to any of claims 15 to 17 wherein there are provided two disabling members arranged in use to cause movement of respective restricting means of respective wheels of a trolley.

19. A trolley according to any of claims 15 to 18 wherein the or each disabling member comprises an arm arranged in use to co-operate with a restricting means.

20. A trolley according to any of claims 1 to 19 wherein the restricting means comprises an abutment member arranged in use to abut an abutment portion of a turning member which turning member is arranged in use to turn with the wheel.

21. A trolley according to claim 20 wherein the turning member is arranged to turn with the wheel in a second direction until a portion of the turning member abuts the abutment member.

22. A trolley according to claim 20 or 21 wherein the turning member comprises a plate member.

23. A trolley according to any of claims 20 to 22 wherein the turning member comprises a cam surface against which the abutment member is arranged to bear during turning of the wheel.

24. A trolley according to any of claims 20 to 23 wherein the abutment member is arranged to move between a first operative configuration in which it is arranged to abut the turning member and a second in-operative configuration in which it is arranged not to abut the turning member.

25. A trolley according to any of claims 20 to 24 wherein the abutment member is arranged to move pivotally between the first and second configurations.

26. A trolley substantially as herein described with reference to the accompanying drawings.