GB2420324A

GB2420324A - Steering and handling device for moving roll cages

Info

Publication number: GB2420324A
Application number: GB0601833A
Authority: GB
Inventors: Steve Mather
Original assignee: Mastermover International Ltd
Current assignee: Mastermover International Ltd
Priority date: 2002-11-11
Filing date: 2002-11-11
Publication date: 2006-05-24
Anticipated expiration: 2022-11-11
Also published as: GB2420324B; GB0601833D0

Abstract

A steering and handling device 1' for moving a roll cage (100, figure 6) which has a generally U-shaped base frame (102) with castor wheels (106) at its forward end and directionally fixed wheels at its rearward end (110). The device 1' includes a body 2 defining a steering axis and having channel means extending in cantilever rearwardly of the steering axis. The channel means are for releasably engaging the base frame (102) of the roll cage (100) between the front castor wheels (106). A steering tiller 4 is pivotally mounted on the body 2 and extends forwardly and upwardly from the body 2 and terminates in a handle portion 10. An axle is fast to the steering tiller 4 beneath the body 2 on which steering wheels are mounted. The angular range of movement of the steering tiller 4 relative to the body 2 is restricted, preferably to a limited range of Ò45{angular movement on each side of straight-ahead alignment, by a radial projection 14 from the steering tiller 4 traversing a recess (25 figure 10) in the body during pivotal turning of the steering tiller 4 relative to the body 2 and engaging against shoulders at the opposite ends of that recess (25) at the limits of movement. That restriction to the angular range of steering movement provides sufficient steering movement to make the device 1' sufficiently manoeuvrable for use within a supermarket whilst preventing sliding of the channel means 36 laterally of the base frame (102) of the roll cage (100).

Description

TITLE

Steering and handling device for moving roll cages

DESCRIPTION

The invention relates to steering and handling devices for moving A-frame roll cages.

Roll cages are generally used for transporting goods over level surfaces, for example from the warehousing sections to the retailing sections of supermarkets. There are two distinct designs of roll cages, known in the trade as A-frame and Z-frame cages.

The distinction between the two lies in the shape, in plan view, of the base frame. So- called Z-frame roll cages have a base frame which is N-shaped, and the roll cages can be nested together by interleaving the base frames of adjacent roll cages slightly in echelon, with the superstructure of successive roll cages folding and nesting together in known mariner. So- called A-frame roll cages have a generally U-shaped base frame, optionally with a reinforcing bar connecting together opposite branches of the U near to the forward end of the roll cage. As with the Z-frame roll cages, cages can be nested together when not in use with a partial collapse of some parts of the superstructure of the roll cage.

This invention relates to a steering and handling device exclusively for so-called A- frame roll cages. Typically the generally U-shaped base frames are made from 50mm x 25mm box section, with castor wheels at the forward end and directionally fixed wheels at the rearward end. The industry standard is that the wheels raise the base frame approximately 160mm from the floor.

When the roll cages are moved around a supermarket, they are designed to be pushed from the rear end of the superstructure, which may be open or closed. That provides a stable movement, but there is a problem in that a fully loaded roIl cage can obscure the view ahead of the person pushing and steering the cage, so that there is a danger that the roll cage can be steered inadvertently into fixed objects or even members of the public in the supermarkets. Some personnel prefer to pull the roll cages, but to do that the superstructure is generally grasped at a relatively high level, which can cause instability of the moving roll cage particularly when it is not weighed down with merchandise.

We have already devised a steering and handling device for moving such an A-frame roll cage, the device comprising a body defming a steering axis and having channel means extending in cantilever rearwardly of the steering axis for releasably engaging the base frame of the roll cage between the castor wheels; and a steering member - pivotally mounted on the body and comprising a steering tiller pivotable about the steering axis, extending forwardly and upwardly from the body and terminating in a handle portion, and wheel means rotatably mounted on an axle mounted on the steering tiller beneath the body.

Initial tests of this earlier device showed that it was capable of moving the roll cages without problems in a straight line or in a wide radius arc, but incapable of manoeuvring the roll cages in tight circles. When the steering tiller of this precursor device was used to turn the roll cage in a tight arc, the channel means slipped laterally across the front bar of the U-shaped base frame of the roll cage, and the wheel means of the device fouled one or other of the front castor wheels of the roll cage, causing the roll cage to jump out of the channel means of the device and become detached.

The steering and handling device could not therefore be used in a supermarket environment, when it was required that the device should remain coupled to the roll cage during manoeuvring movements, for example when the roll cage was making tight turns at the ends of aisles or was being shunted from one side of an aisle to the other in a series of forward and rearward movements.

During the development of the original idea it was considered important that the device should be capable of steering and handling existing roll cages without modification to the roll cage itself. For that reason the previously tested device included a universal coupling in which the channel means on the body was designed to engage the base frame of the roll cage releasably between the castor wheels. At this zone the U-frame of the roll cage is a portion of 50mm x 25mm box section which is standard between roll cages of different manufacture. The original concept was that the cantilever arrangement of the channel means on the body would make it possible to bring the device of the invention into engagement with a roll cage easily and reliably. The steering tiller, when raised, would cause the body to swivel around the axle and the channel means to lower by virtue of its cantilever mounting. The channel means would then be passed beneath the portion of the base frame of the roll cage which extends between the castor wheels, and then simple lowering of the steering tiller would be sufficient to raise the channel means to bring it into releasable engagement with the base frame.

The initial solution to the above problem of inadvertent detachment of the roll cage when turning corners was to modif' the connection between the device and the roll cage, but all such modifications required modification to the roll cage base frame itself, and therefore departed from the prime objective of the original design which was to provide a device which could be used with an existing stock of roll cages without requiring modification of those roll cages.

It is therefore an object of the invention to provide a modified steering and handling device for increasing the ease with which shop assistants or warehousing personnel can safely manoeuvre A-frame roll cages in a potentially crowded environment, which avoids the above problem of detachment of the device from the roll cage when turning tight corners, and which does not require modification of the roll cages.

THE INVENTION.

The invention provides a steering and handling device for moving a roll cage which has a generally U-shaped base frame with castor wheels at its forward end and directionally fixed wheels at its rearward end, the device having the features specified in claim I herein.

As with the known precursor, because the channel means engages the roll cage at a low point, the roll cages can be moved safely whether full or empty, without any risk of causing them to overbalance as happens when the user tries to steer the roll cage by grasping the superstructnre portion. However the limitation to the pemiitted angular range of movement, preferably to about 450 on each side of straight-ahead alignment, is sufficient to ensure that the channel means does not slide laterally along the front portion of the base frame of the roll cage when the roll cage is pulled around corners.

As with the original known precursor device, the channel means may comprise an inclined forward face, a bottom face and a rearward face for surrounding three sides of the base frame of the roll cage, and a retention lip extending forwardly of the top edge of the rearward face to lap over the top of the base frame of the roll cage to engage the base frame when the steering axis of the device is in a substantially vertical orientation. However it has been found that a greater resistance to lateral sliding of the channel means along the front portion of the base frame of the roll cage is achieved if the retention lip portion of the channel means which extends forwardly from the top edge of the rearward face to lap over the top of the base frame is limited to two relatively short retention lips one at each end of the channel means. A resilient connection between the body and the steering member greatly assists the engagement and disengagement of the channel means with the base frame of the roll cage. To that end a resilient member is preferably positioned between the axle and the body so as to bias the body away from the axle. That resilient member is preferably a coil spring around the steering tiller below the body, in compression between the axle and the body.

The axle is mounted on the steering tiller, so that pivotal movement of the tiller within the limited range of angular movement about the steering axis causes the wheel means mounted on the axle to follow the pivotal movement of the tiller. It is highly desirable for the tiller to have a releasable lock means for locking it in the straight- ahead position relative to the body when the roll cage is parked or when the steering and handling device is disengaged from the roll cage. That releasable lock means can be incorporated into the design by making use of the resilient member biasing the body away from the axle. Preferably the axle mounts two wheels, which should be spaced sufficiently closely together that they do not foul the roll cage when steering the cage. Also the length of the channel means and the size and spacing of the wheel means mounted on the axle should be such that a full 3600 turning circle is permitted of the castor wheels at the forward end of the roll cage, without fouling the steering and handling device.

DRAWINGS

Figure 1 is a front upper perspective view of a prior construction of a steering and handling device for a roll cage; Figure 2 is a rear lower perspective view of the steering and handling device of Figure 1; Figure 3 is a front detail of the steering and handling device of Figure 1; Figure 4 is side detail of the steering and handling device of Figure 1; Figure 5 is a plan view of the steering and handling device of Figure 1 releasably engaged with the U-shaped base frame of a roll cage; Figure 6 is a side view showing how the steering and handling device of Figure 1 is releasably engaged with the U-shaped base frame of a roll cage at a first instance in time; Figure 7 is a side view showing how the steering and handling device of Figure 1 is releasably engaged with the U-shaped base frame of a roll cage at a second instance in time; Figure 8 is a side view showing how the steering and handling device of Figure 1 is releasably engaged with the U-shaped base frame of a roll cage at a third instance in time; Figure 9 is a front upper perspective view of a roll cage steering and handling device according to the invention; Figure 10 is a rear upper perspective view of the device of Figure 9; Figure 11 is en enlarged detail from Figure 10; Figure 12 is a side elevation of the device of Figure 9; Figure 13 is a front view of the device of Figure 9; and Figure 14 is a plan view froim above of the device of Figure 9.

A steering and handling device which is the precursor of the device of the invention (hereinafter refereed to as "the precursor device") will first be described with reference to Figures 1 to 4. The precursor device 1 includes a body 2 and a steering tiller 4. The lower end of the steering tiller 4 passes through a pair of holes in the body 2 so that it is pivotally mounted. An axle 6 is fast to the lower end of the steering tiller 4 beneath the body 2 and a steering wheel 8 is rotatably mounted at each end of the axle 6. Pivotal movement of the steering tiller 4 therefore causes the steering wheels 8 to turn so that the precursor device I can be steered about a steering axis. The upper end of the steering tiller 4 terminates in a handle portion 10 and the lower end of the steering tiller 4 is joined to the upper end by means of a swannecked portion 12 that is reinforced by a web 14. In use the lower end of the steering tiller 4 is vertical so that the steering axis is vertical, and the upper end extends forwardly and upwardly from the body 2 so that the handle portion 10 can be grasped by the shop assistant or warehousing personnel.

The body 2 is free to move axially along the lower end of the steering tiller 4 but is biased away from the axle 6 by a coil spring 16 (Figure 3) . The body 2 includes an upper collar 18 that is biased into contact with the web 14 to provide an upper limit to the axial movement of the body. A lower limit to the axial movement of the body 2 is provided by the underside of the body 2 which contacts an upper face 22 forming the upper end of a sleeve 42 around the steering tiller 4 when the coil spring 16 is compressed. The body 2 has an axial travel of about 15mm between the upper and lower limits.

When the precursor device 1 is not in use the web 14 can engage with a Vshaped recess 24 provided in the upper collar 20 to lock the steering tiller 4 and the steering wheels 8 in the straight-ahead position relative to the body 2.

The body 2 includes an engaging structure 26 (see Figure 4) extending in cantilever rearwardly of the lower end of the steering tiller 4. The engaging structure 26 has an inclined forward face 28, a bottom face 30 and a rearward face 32. A retention lip 34 extends forwardly from a top edge of the rearward face 32. The three faces together create a channel 36 for receiving the base frame of a roll cage as described in more detail below. A pair of L-shaped reinforcing beams 38, 40 surround the bottom face and the rearward face 32 to provide additional strength.

An A-frame roll cage (hereinafter referred to as the "roll cage") will be described with referencc to Figures 5 to 8. The roll cage 100 includes a U-shaped base frame 102 and a superstructure 104. A pair of castor wheels 106 are provided on mounting brackets 108 at the forward end of the roll cage 100 and a pair of fixed wheels 110 are provided on mounting brackets 112 at the rearward end of the roll cage. The wheels 106, 110 of the roll cage 100 raise the base frame 160mm above the floor. However, any slight deviation in this figure can be accommodated by the axial travel of the body 2. The base frame 102 is made from 50mm x 25mm box section and the dimensions of the engaging structure 26 are chosen so that the base frame is tightly received within the channel 36.

The full 360 turning circle of the castor wheels 106 is represented by the dashed line 114 in Figure 5. From this it can be seen that the length of the engaging structure 26 and the spacing of the steering wheels 8 must be such that they do not foul the castor wheels 106. It will also be seen that the steering wheels 8 must be spaced sufficiently close together that they do not foul the base frame 1 O2 when steering the roll cage.

The method of engaging the precursor device 1 with the roll cage 100 will now be explained with reference to Figures 6 to 8. First the steering tiller 4 is raised causing the body 2 to swivel around the axle 6 and the engaging structure 26 to lower by virtue of its cantilever mounting. The steering tiller 4 is raised until the rearward face 32 and the retention lip 34 are below level of the base frame 102 as shown in Figure 6. The engaging structure 26 can then be passed beneath the portion of the base frame 102 which extends between the castor wheels 106 as shown in Figure 7. The steering tiller 4 is then lowered so that the lower end of the steering tiller is brought vertical and the base frame 102 is tightly received within the channel 36 as shown in Figure 8.

As the base frame 102 is canimed into the channel 36 along the inclined forward face 28, the body 2 is forced axially down along the lower end of the steering tiller 4 against the bias of the coil spring 16. This downward movement releases the web 14 from the V-shaped recess 24 to allow the steering tiller 4 to pivot freely. Once the precursor device I is engaged with the base frame 102, the intention was that it could be used to steer and handle the roll cage 100 using the steering tiller 4.

To disengage the precursor device 1 from the roll cage 100 the above method is simply carried out in reverse.

The disadvantage of the precursor device I was that when the steering tiller 4 was turned through a significant angle, as frequently happened in practice, the engaging structure 26 tended to slide laterally of the front section of the base frame 102 of the roll cage 100, in the direction of the double-headed arrow A-A of Figure 5. That brought the steering wheels 8 within the turning circle 114 of the castor wheels 106 of the roll cage 100, and the resulting impact either jammed the roll cage 100 preventing further movement or, more often than not, caused the roll cage to jump out of the channel formed by the engaging structure 26, thus detaching the roll cage from the precursor device 1.

Figures 9 to 14 illustrate a device 1 according to the invention which has been modified to prevent the above disengagement. In Figures 9 to 14 the same reference numerals have been used wherever possible to identify the same components as in Figures 1 to 8, and only the material differences between the two devices will therefore be described below.

The device 1' illustrated in Figures 9 to 14 comprises a body 2 defining a steering axis and having a steering means comprising a steering tiller 4 and steering wheels 8, just as with the precursor device I. The channel means extending in cantilever rearwardly of the steering axis to provide the engaging structure 26 for releasably engaging the base frame 102 of the roll cage 100 is substantially the same as in Figures 1 to 8 except that in place of the L-shaped reinforcing beams 38, 40 of Figures 1 to 8 there are provided feet 38', 40' which perform the same reinforcement of the bottom face and the rearward face 32 of the engaging structure (although more robustly). The feet 38', 40', however, extend downwardly arid rearwardly from the engaging structure 26 to allow the device 1' to be balanced on the feet and wheels 8 with the steering tiller 4 generally vertical for storage. Also, the retention lip 34 of Figures 1 to 8 which extended the full width of the body 2 has in the device I been restricted to two relatively short retention lips 34' positioned outwardly of the feet 38' and 40'. It has been found that limiting the retention lip means to a small retention lip at each lateral end of the channel means restricts the tendency of the engaging structure to slide laterally across the base frame 102 when the steering device 1' is used to steer the roll cage 100 around corners.

Principally, however, the tendency of the engaging structure to slide laterally across the base frame 102 is avoided by a recess 25 in the top wall of the upper collar 20 which receives the web 14 and restricts the extent of angular movement of the tiller 4 relative to the body 2.. Always the web is limited to an angular range of movement of about 900, being 450 from each side of the straight-ahead position of the tiller 4. At opposite ends of that limit of permitted movement the web 14 strikes a shoulder at one end or the other of the recess 25. Within the relatively narrow range of angular steering movement permitted, the engaging structure 26 remains in position around a central part of the front bar of the base frame of the roll cage and does not slide to the right or to the left during steering of the roll cage. Yet the steering angles allowed are sufficient to cope with all the manoeuvrability that is expected of a roll cage in a supermarket environment.

Another feature of the device 1' over the device 1 is that the body 2 is formed with an angled rear kick plate 3 with which a user can guide the wheels towards a roll cage 100 with which the device 1' is to be connected, and with which the user can hold the device I' against the base frame of the roll cage while the steering tiller is raised and then lowered to bring the channel means under and around the base frame of the roll cage 100. Also, a hanging hook 5 is provided on the tiller to enable the device 1' to be hung on the side of a roll cage 100 when it is desired to decouple the steering device from the roll cage but retain it close to hand for example when working in a supermarket aisle.

Claims

1. A steering and handling device for moving a roll cage which has a generally U-shaped base frame with castor wheels at its forward end and directionally fixed wheels at its rearward end, the device comprising: a body defining a steering axis and having channel means extending in cantilever rearwardly of the steering axis for releasably engaging the base frame of the roll cage between the castor wheels; and a steering member pivotally mounted on the body and comprising a steering tiller pivotable about the steering axis, extending forwardly and upwardly from the body and terminating in a handle portion, and wheel means rotatably mounted on an axle mounted on the steering tiller beneath the body. wherein the angular range of movement of the steering tiller relative to the body is restricted to a limited range of angular movement on each side of straight-ahead * alignment.

2. A device according to claim 1, wherein the angular range of movement of the steering tiller relative to the body is limited to about 45 on each side of straight- ahead alignment.

3. A device according to claim I or claim 2, wherein the angular range of movement of the steering tiller relative to the body is limited by a radial projection from the steering tiller traversing a recess in the body during pivotal turning of the steering tiller relative to the body and engaging against shoulders at the opposite ends of that recess at the limits of movement.

4. A device according to claim 3, wherein the radial projection is a flange forming a web reinforcing an angled portion of the steering tiller.

5. A device according to any preceding claim, further comprising a resilient means positioned between the axle and the body so as to bias the body away from the axle.

6. A device according to claim 5, wherein the resilient means is a coil spring around the steering tiller below the body, in compression between the axle and the body.

7. A device according to claim 5, further comprising releasable lock means for preventing relative pivotal movement between the steering member and the body and locking the steering tiller in the straight ahead position relative to the body.

8. A device according to claim 7 when appended to claim 3, wherein the releasable locking means comprises the radial projection from the steering tiller which, when the body is biased away from the axle under the bias of the resilient means, engages in a recess in the body to prevent relative pivotal movement between the steering tiller and the body but which can be released from the recess to release the locking means by compression of the resilient member.

9. A device according to claim 8, wherein on either side of the recess is a cam slope formed on the body to encourage the detent portion to enter the recess under the bias of the resilient means.

10. A device according to any preceding claim, wherein the wheel means comprise one wheel at each end of the axle.

11. A device according to any preceding claim, wherein the channel means comprises an inclined forward face, a bottom face and a rearward face for surrounding three sides of the base frame of the roll cage, and retention lip means extending forwardly from the top edge of the rearward face to lap over the top of the base frame of the roll cage to engage the base frame when the steering axis of the device is in a substantially vertical orientation.

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12 - 12. A device according to claim 11, wherein the retention lip means comprises a retention lip at each lateral end of the channel means.

13. A device according to any preceding claim, further comprising a pair of supporting feet positioned to allow the device to be balanced on its wheel means and on the supporting feet with the tiller means in a substantially vertical orientation for storage purposes.

14. A device according to claim 13 when appended to claim 12, wherein the supporting feet are formed at the ends of brackets which extend up to or around the retention lips to reinforce the retention lips against flexure in use.

15. A device according to any preceding claim, further comprising a hook on the tiller means for hanging the device on the side of a roll cage when not in use.

16. A device according to any preceding claim, wherein the body is formed with an angled rear kick plate with which a user can guide the device on its wheel means towards a*roll cage and with which the user can hold the device against the base frame of the roll cage while the steering tiller is raised and then lowered to bring the channel means under and around the base frame of the roll cage to releasably engage the base frame.