GB2423242A

GB2423242A - Castor for supermarket trolley with swivel lock triggered at shop exit

Info

Publication number: GB2423242A
Application number: GB0503202A
Authority: GB
Inventors: Thomas Barrow Dowling
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-02-16
Filing date: 2005-02-16
Publication date: 2006-08-23
Also published as: GB0503202D0

Abstract

A trolley such as a supermarket trolley which is freely castoring inside a chosen space such as the store but which on passing the exit to the draining and therefore not level surface of the car park is activated by a signal which renders one or two of the castoring wheels non - castoring and thus the trolley easily steerable. On passing over a shallow step down 10 in the surface of the exit, constituting a physical signal, a partially sprung supported inertial mass is mounted to rise 12 relative to the castor 2 releasing a sprung stud 4 to engage in indent 5 in the fixed part of the castor 2 fixing the castor in the ahead position. The full castoring is restored by physical contact with the trolley or trolley bay ahead 15 when the trolleys are nested prior to return to the store entrance. The swivel locking of the castor wheel can be triggered by electronic, magnetic, sonic, light, or physical signal means.

Description

1 2423242

TROLLEY

The present invention relates to a device for engaging a castor wheel in a determined orientation, particularly though not exclusively a castor wheel of a trolley.

When loaded, trolleys having castor action wheels tend to follow their previous line of travel at corners due to inertia. Also on ground which is not flat they tend to move sideways in a downhill direction. In either case, .steering becomes difficult. This flaw is alleviated by the use of a wide handling bar at the rear with which the operator can exert a twisting, thus a straightening effect, or by crabbing the trolley across a slope at an angle to strike a balance. This problem is well known by visitors to supermarkets and airports, but applies also in hospitals, warehouses, places of work, and in any other place where castor action wheels are used.

In the case of supermarket, airport and railway station trolleys, for instance, it is a normal requirement that the trolleys be nested when not in use, as well as for returning them in convoy for re-use. When nested it is necessary for all the castors or at least all but one (pair), to be free to swivel, even when only two trolleys are nested, so that they can be manoeuvred into neat assemblies without shunting or the need to reverse them.

The requirement for supermarket trolleys will now be addressed.

The trolleys are normally mounted on four wheels. The four wheel

trolley will be assumed in this description.

US Patent 2,583,858 filed on December 10th 1949 by J K Kostolecki was taken out to solve the problem of directional stability.

Kostolecki employs a spring biased ball engaging in a groove in the manner of a detent to bias a castor wheel to maintain a single direction until excess force disengages the detent and ftill castor action is permitted. The problems of manoeuvring nested trolleys and free movement in any direction at slow speeds were not addressed by him.

My experiments indicate that either the detent action is too strong to be disengaged when necessary or it is too weak to be effective in providing a trolley with directional stability.

European Patent No. 0,370,716 Bi, filed 20th November 1989 by Herok RJK Ltd, inventor Paul Star France, describes an arrangement for holding a castor wheel in straight ahead position, but it can be restored to its normal castor action only by reversing of the direction of rotation. I regard this as a significant impediment to easy manoeuvrability of a trolley or a convoy of nested trolleys.

In May 1994, at the Birmingham NEC The Great British Innovation and Inventions Fair' on the Safeway (supermarket) stand an invention was exposed that partially solved the problems described above, but only at the expense of introducing another problem. On the two front wheels of the trolley a knuckle engaged a cam and slot, essentially as described in Kostolecki's patent. The action is only engaged when the operator draws towards him a connected controlling bar mounted parallel with, and just in front of, the main bar or handle of the trolley. Thus the nesting problem was solved as was the free manoeuvring from rest or slow speeds. I reject this approach, on the grounds that its use requires the co- operation of the shopper and is also quite unsuited to airport and railway trolleys in that they already mount an identical operating bar for brake release. To manage one control, let alone two, in addition to the main handle is considered an unsatisfactory burden to the user.

My patent GB 2290 022 B Titled Trolley addresses the problem by using the speed of the trolley itself as the control. This was based on the observation of the practice of shopping in supermarkets which is to move around the store mostly at slow speeds and certainly to slow down in way of obstacles but to proceed at a steady speed to the vehicle to unload the trolley. Thus when the shopper pushed the trolley faster than a selected speed a castor or a pair of castors on the trolley are rendered directional making the trolley easy to steer in the car park.

Proceeding from the speed of the trolley as the control of the trolley's directional mode the present invention which is also primarily aimed at shopping trolleys makes use of a signal at the exit(s) of the shop or store. It is now universal that the floor of a supermarket is level.

Therefore the requirement for directional stability inside the store does not exist - quite the reverse - the ability to move the trolley sideways is an advantage.

On leaving the supermarket, normally into the open air, directional stability is immediately required as the surface will be not level in order to facilitate drainage. I therefore separate the trolley requirement into three modes - inside the store, unconstrained, outside the store with directional stability and thirdly to be manageable for the store operatives on the return journey from the car park to the store entrance.

The signal to trigger the switch to directional stability may be by remote control by electronic, magnetic, sonic, light or by physical means or a combination of these means. The requirement to pass the signal indicates that all the trolleys must be arranged to pass out of the store within range of the signal. Depending on the type of signal it may be necessary to separate the exit (s) from the entrance (s) as indeed is often the existing case.

To achieve directional stability one castor must be restrained in the ahead position. Its laterally adjacent castor may be restrained as well but this is not a requirement. The restrained wheel(s) is assumed to be a forward wheel though the rear wheel option is available. The restraint of the directional wheel will not occur until the castor is passed through the directly ahead orientation.

In this way the operator of the trolley or shopper will be free to move the trolley without constraint whilst in the store but, on leaving the store and passing the signal referred to, will find the trolley automatically directionally stable until the trolley is discarded in the trolley park for further use.

At some point after the shopper has discarded the trolley a further signal is arranged to be received by the trolley to disengage the directional mode in readiness for the next shopper.

To help understanding of the invention a specific embodiment thereof will now be described with reference to the accompanying drawings in which:Figure 1) shows a side sectional elevation of a modified castor in the disengaged or in-store mode, with figure 2 showing its corresponding end elevation as seen from the rear.

Figure 3) shows a similar presentation of the castor in the engaged or directional mode.

The castor shown is conventional. The trolley itself, a leg 1 of which is drawn and the part of the castor 2 fixed to it locates the castoring part of the assembly, which is all else from here 3 downwards.

The aim of the invention is to control the action of the spring 14 loaded engaging stud 4 on the castoring wheel into a receiving slot 5 on the circumference of the fixed part of the trolley wheel 2. This engaging stud 4 located to slide to engage and disengage in fixed structure 8 mounted on the rotating part of the castor is, in the shopping mode restrained in the disengaged position by the retaining stud 13 mounted on mass 6 which by gravity registers in a slot in the engaging stud 4 thus preventing movement and thus engagement.

In the embodiment now described, the physical signal path is chosen to achieve the aim. The controlling mass 6 trailing and located broadly horizontally by fixed pivot 7 on the fixed added structure 8 and preferably partially supported by spring 9, wills by geometry and in this embodiment aided by spring support, tend to resist a change in spatial position when the horizontal movement of the trolley is disturbed, for instance when passing over a downward step 10. This downward step constitutes the engagement signal. In the case where the trolley passes over the downward step the trolley and wheel follow the contour to the lower level 11, whilst the controlling mass 6 will by inertia and preferably partially assisted by the spring 9 remain nearer to its previous position in space 12 (Fig.3) and thus raised in relation to the fixed structure 8.

The resultant raising of the controlling mass now 12 in figure 3, will raise the retaining stud 13 which releases the springl4 loaded engaging stud 4 allowing it to engage in the slot 5 and thus lock the castor wheel in the ahead position the next time the trolley operator thus directs the trolley.

In this way the trolley is directionally controllable until such time as this mode is disengaged.

The signal and trigger to disengage the directional mode is by a disengaging wand -like member 15 attached to the trolley ahead in the stack. This member which may be flexible is so positioned as to exert a horizontal rearward movement on the receiving buffer- like disengaging member 16, thus returning the trolley to the non-directional controlled mode by reversing the action described above and thus ready for the next shopper.

The normal practise in supermarket car parks is to locate convenient trolley parks where the no longer required trolleys are deposited. An operator will then nest same design trolleys one overlapping inside its next ahead until he has a number stacked together for the manually assisted return to the store entrance ready for the next shoppers. These stacks are normally strapped together in tension whilst on the move. It may be an advantage for the leading trolley in a stack to be directionally stable or not. In the latter case means corresponding to disengaging member 15 referred to above may be mounted on the structure of the trolley park or in the other case the lead trolley can be disengaged by similar means at the ready use trolley park outside the store entrance. The route from the ready use trolley park outside the store entrance to the inside of the store itself must be sufficiently smooth & fair as not to re-engage the directional mode.

Unlocking bays fitted with a disengaging member 15 may be situated inside the store to disengage a trolley which is found to be in directional mode for example when a shopper picks up a stray trolley in the car park which will be in that case still in directional mode.

Similarly a tap on the disengaging buffer member 16 at any time will disengage the directional mode.

Claims

1. A trolley mounted on normally four fully castoring wheels which on passing a signal at the exit of the shop or store is triggered to switch to directional stability the next time the operator of the trolley directs the trolley through the ahead orientation, the locking of one or two adjacent leading or rearward wheels being by engagement of a stud on the castoring part of the wheel assembly with a receiving slot on the fixed part of the trolley wheel.

2. A device as claimed in claim 1 wherein the signal is physical.

3. A device as claimed in claim 1 wherein the signal is magnetic.

4. A device as claimed in claim I wherein the signal is electronic.

5. A device as claimed in claim 1 wherein the signal is sonic.

6. A device as claimed in claim I wherein the signal is by light.

7. A device as claimed in claim 1 wherein the signal is by a combination of the described means.

8. A device as claimed in claim I wherein the device as claimed in claim I wherein the engagement of the stud of the castoring part of the wheel is spring assisted.

9. A device as claimed in claims 1 and 2 wherein the signal constitutes a step in the ground surface thereby transmitting an inertial signal to a controlling mass causing the castor to lock in the ahead position the next time the trolley operator thus directs the trolley.

10. A device as claimed in claim 9 wherein the controlling mass is partially spring supported.

11. A device as claimed in herein before whereby the directionally controllable trolley is disengaged from the directional mode by a further signal.

12. A device as claimed in claim 11 wherein the signal is by physical contact with the trolley ahead in a stacked nest.

13. A device as claimed in claim 11 wherein the leading trolley in a nest is disengaged by physical contact with the structure of the trolley park.

14 A device as claimed in claim 11 constituting an unlocking bay to disengage a stray trolley in the same manner as in claim 13.

15. A device for engaging and disengaging a castor wheel in the ahead orientation substantially as described with reference to the accompanying drawings.

Amendments to the claims have been filed as follows

A trolley typically as found in supermarkets which is arranged to be fully castoring inside the store but directionally stable and steerable outside in the draining and therefore not level area,the change in mode being triggered by inertial means when the trolley passes over a threshold in the form of a downward step at the exit of the store.

2 Inertial means as claimed in claim 1 in the form of an inertial switch mounted on a castor wheel on the swivelling part of the castor which when the trolley is passed over a downward step results in a controlling mass rising relative to the castor and thus releasing a spring-assisted engaging stud to move into an indent in the fixed, non- rotating, part of the castor the next time the trolley operator directs the trolley through the ahead orientation.

3 A device as claimed in claim 2 where in the controlling mass is partially spring- supported.

* 4 Means in a trolley park where discarded trolleys are collected arranged to co-operate with complimentary means on a trolley to disengage the directional mode described.

Means in a store as claimed in claim 4 to disengage a single stray trolley.