GB2339556A - Steerable shopping trolley - Google Patents

Description

2339556 Shoppina Trolleys This invention concerns shopping trolleys and in

particular steerable shopping trolleys.

Shopping trolleys, sometimes referred to as shopping carts, usually consist of a wire basket supported on a framework including four wheels which contact the ground and enable the trolley to be moved. Such trolleys can be moved in a straight line by pushing them from the rear using a horizontal bar attached to the basket. However, in order to enable them to be steered, at least two, and more generally all four, of the wheels are on castors which allow the alignment of the associated wheels to be changed. Steering of the trolley can then be effected by pushing one side of the trolley whilst holding the other side back.

Despite the provision of castors to facilitate the steering of such trolleys, the poor steerability of supermarket trolleys is well known to the general public. Furthermore, the provision of 2 four castors rather than two makes little overall difference to their manoeuverability.

Attempts have been made to improve the steerability of supermarket trolleys, for example by providing hand operated brakes which operate on the wheels on one or other side of the trolley, thereby causing the trolley to turn towards the side where the brake is applied. The mechanisms used to effect such braking are complicated, and are therefore expensive both to produce and maintain.

According to the present invention there is provided a shopping trolley comprising a container for receiving shopping or the like, and a frame with four castors with wheels for enabling the trolley to be pushed along by a user and to which the container is attached, the rear two of said four castors being resiliently attached to the frame so that on pushing downwardly on one or other rearward corner of the container the diagonally opposing corner of the container is lifted.

An embodiment of trolley in accordance with the present invention will now be described by way of example with reference to the accompanying diagrammatic drawing which shows a rear view of a supermarket trolley.

The illustrated trolley has a conventional wire basket 1 mounted on a frame 2 having four legs 3 to each of which are attached castors 4 which include wheels 5, only the rear two legs 3 and castors 4 being visible in the drawing.

Each of the two castors 4 as seen in the drawing are attached to the associated legs 3 by a compressible linkage indicated generally at 6, the linkage 6 consisting of a connecting bolt 7 and a spring 8, the castors 4 being free to slide on the bolts when the springs 8 are compressed. The two front castors (not shown) are connected to their associated legs (not shown) in conventional manner, that is by bolting them together but without the inclusion of a spring 8. In this case there can be no relative movement between the castors and the associated legs other than the normal castor action of the wheel being able to rotate about a vertical axis to enable changes of direction to be made.

The illustrated trolley can be pushed in a straight line in conventional manner by pushing substantially horizontally on the handle 9 from the rear of the trolley. However, if whilst pushing from the rear a downward force is also applied to one or other end of the handle 9, for example as indicated by the arrows 10 and 11, the spring 8 associated with the castor 4 directly below the applied downward force will be compressed. The result will be that the leg 3 directly below the applied force will be pushed downwardly, thereby compressing the associated spring 8, and causing the container 1 and the frame 2 to rotate slightly about a diagonal axis through the other rear castor 4 and the front castor (not shown) which is in front of the leg 3 which has been pushed down. when this happens the frictional forces on opposing sides of the trolley differ, those on the side of the trolley which has been pushed down being higher than those on the other side, and the trolley steers towards the side which has been pushed down.

Releasing the downward pressure applied to one side of the trolley enables the springs 8 to return the container 1 to its normal substantially horizontal orientation, thereby restoring the frictional forces on opposing sides of the trolley to being substantially the same. The result is that the trolley then moves in a straight line when a substantially horizontal force is applied to the handle 9.

The application of a downward for-ce to the handle 9-can facilitate steering of the trolley merely by reducing the frictional forces on one of the front wheels on the ground whilst maintaining all four wheels in contact with the ground. However, it is usually preferred that sufficient relative movement is obtained between the leg 3 and the associated castor 4 4 to lift the diagonally opposing front wheel slightly off the ground.

The present invention has the advantage not only of being effective and simple, but it can often be introduced to existing trolleys merely by changing the conventional bolt used to secure a castor 4 to a leg 3 by a longer bolt and a spring 8.

Although the present invention has been particularly described using a compressible spring between the leg 3 and the castor 4, other compressible means can be used, for example rubber or other resilient materials. It will also be appreciated that more complex mechanical arrangements could be used to enable relative movement to be obtained between the legs 3 and the castors 4.

claims 1. A shopping trolley comprising a container for receiving shopping or the like, and a frame with four castors with wheels for enabling the trolley to be pushed along by a user and to which the container is attached, the rear two of said four castors being resiliently attached to the frame so that on pushing downwardly on one or other rearward corner of the container the diagonally opposing corner of the container is lifted.

2. A trolley according to claim 1, wherein the resilient attachment includes a spring.

3. A shopping trolley substantially as herein described with reference to the accompanying drawing.