GB2448769A

GB2448769A - A wheelbarrow with several pivot points

Info

Publication number: GB2448769A
Application number: GB0708262A
Authority: GB
Inventors: James Edward Galer
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-04-28
Filing date: 2007-04-28
Publication date: 2008-10-29
Anticipated expiration: 2027-04-28
Also published as: GB2448769B; GB0708262D0

Abstract

A wheelbarrow 1, the wheelbarrow comprising a tray 10 or container in which a load is transported, a wheel-mounted support frame to support the tray, the support frame including two or more wheels 15 to enable the wheelbarrow to be moved, from place to place, the tray having a handle 24 enabling the user to move the wheelbarrow and lift the tray, a primary pivot pair 12 extending laterally from opposite sides of the tray resting on primary pivot supports provided in the support frame, and one or more further pivot pairs 13, 14 sequentially engaging pairwise further pivot supports, located forward of the primary pivot supports, as the tray is tipped to discharge a load (see figures 3 to 5). The wheelbarrow may comprise securing means to secure the tray to the frame so as to prevent tipping of the tray when not required, and a motor for both driving the wheelbarrow and tipping the tray.

Description

AN IMPROVED WHEELBARROW

Field of the Invention

The present invention pertains to an improved wheelbarrow. The wheelbarrow is particularly suitable for transporting asphalt, for example during road resurfacing

Background to the Invention

In order to facilitate transport of materials by an individual, particularly around the garden or construction sites, the wheelbarrow is one of the most common and useful devices. Documentary evidence of the use of a wheelbarrow is available going back for around 2000 years, although whether the honour for its invention belongs to Greece or China is a matter for debate.

Wheelbarrows typically have a single wheel (although two, three and four wheeled devices are also in common usage) towards the front of the device which bears the weight of the tray and the goods therein. Two handles are fixed to the tray to the rear of the device to enable the user to lifi the load and manoeuvre the device. When the device is at rest, two legs to the rear of the underside of the tray act, along with the wheel, as supports.

Using such devices quite heavy loads of around 100kg can be readily moved.

However, the difficulty remains for the user of unloading the transported materials at their destination. In order to do this the user has to apply upward force to the handles, which force acts about the pivot point (in the case of a wheelbarrow having one wheel the pivot is the axis of the wheel) of the wheelbarrow causing the tray to tip and the load to be discharged.

Firstly, however to supply the force required may be difficult. Moreover to control the discharge at the same time as exerting the force can also be problematic. The problem is exacerbated when the load being carried is a viscous material such as asphalt. The high viscosity can lead to an initially slow discharge on tipping followed by a surge, leading to a sudden change in weight distribution towards the front of the wheelbarrow causing difficulties to the user. Control here is more important when one considers the high temperature at which the asphalt is transported to maintain its flow characteristics. Even with solid materials, the change in the centre of gravity of the load and the tray during discharge can mean that the user suddenly has to switch from exerting an upward force to applying a downward force to prevent too rapid tipping.

It is an object of the present invention to address the above problems and provide a wheelbarrow which is controllably dischargeable.

Summary of the Invention

According to the invention there is provided a wheelbarrow, the wheelbarrow comprising a tray or container in which a load is transported, a wheel-mounted support frame to support the tray, the support frame including two or more wheels to enable the wheelbarrow to be moved, from place to place, the tray having a handle enabling the user to move the wheelbarrow and lift the tray, primary pivot pairs resting on primary pivot supports, and one or more further pivot pairs sequentially engaging pairwise further pivot supports, laterally displaced from the primary pivot supports, as the tray is tipped to discharge a load.

In this manner the support for the load moves in the direction of change of centre of gravity of the load as the load tips out preventing undue increase of torque on the tray and facilitating smooth discharge of a load.

Optionally, the tray includes one or more legs on which at least a portion of the weight of the tray can be supported. The wheelbarrow can therefore be left to stand freely.

Preferably the support frame includes a transverse cross-piece on which the tray rests, and on which the weight of the tray and the load can be supported.

Optionally securing means can be included securing the tray to the support frame to prevent tipping of the tray when not required.

The forward end of the tray preferably slopes at an angle between the horizontal and the vertical. This feature facilitates tipping and also results in the load being able to be carried closer to the ground. This improves the stability of the wheelbarrow by allowing the centre of gravity of the wheelbarrow to be lower.

The wheelbarrow preferably includes a motor to drive motion of the wheelbarrow and reduce strain on the user. The motor further preferably is linked to the tray to tip the tray when discharging a load.

Brief Description of the Drawings

The invention will now be described with reference to the accompanying drawings which shows by way of example only one embodiment of a wheelbarrow. In the drawings: Figure 1 is a side view of a wheelbarrow; Figure 2 is a perspective view of the discharge of a wheelbarrow; and Figures 3-5 illustrate the discharge of the load from the tray.

Detailed Description of the Invention

The wheelbarrow (generally referenced I in Figure 1) described below is suitable for carrying heavy loads, up to around 300-350kg, which is greater than is typical for standard wheelbarrows. It is envisaged that the tray containing the load is formed from metal or from a plastics material, although the material should be selected from those suitable for the load to be carried. For example, where the load is to carry fluid asphalt the material should be able to withstand high temperatures.

Referring initially to Figures 1 and 2 these show a wheelbarrow 1. The wheelbarrow I in its basics has a wheel mounted chassis supporting a tray in which the load sits during transportation. The wheelbarrow I can be manoeuvred by using the handle, which also serves to tip the tray when unloading the wheelbarrow 1.

The tray 10 in which the load is carried is generally cuboidal in shape with the upper surface open to allow the load to be charged into the tray 10. The base of the tray 10 is sloped at forward surface 11 to facilitate discharge of load.

The outer surface of the tray 10 bears three protruding pivot lugs 12,13,14 of generally circular cross-section. The opposite side of the tray 10 bears corresponding pivot lugs.

In order to support the tray 10, and to house the wheels 15, the wheelbarrow I includes a chassis 16. The chassis 16 also bears two tray supports 17. In the embodiment shown in Figure 1, each support 17 has a stepped configuration with the upper surface 18,19 of each step including a semi-circular notch 20,2 1 of similar size to the diameter of the pivot tugs 12,13. The chassis 16 itself also includes a semi-circular notch 22. Further support for the tray 10 in the rest position is provided by rear support beam 23.

In its normal configuration the tray 10 rests on the chassis 16 and is supported by engagement of the lug 12 in the notch 20. The wheelbarrow I can then be moved from place to place by applying a lateral force to the handle 24.

In order to facilitate the tipping process, the present invention contemplates a supported pivotal tipping motion via the pivot tugs 12-14. As the user applies upward force to the end of the handle 24, the tray 10 pivots about the lug 12, which is pivotally retained in the notch 20. Eventually, the tray tips over such that the pivot lug 13, having followed the path shown by arrow A, engages the support notch 21.

The weight of the load and the tray 10 is therefore now pivoted about a new point which, due to the mass of the material having been tipped forward, is closer to the new centre of gravity of the toad. Further tipping of the load is therefore facilitated. As the load is tipped yet further the centre of mass of the load moves further forward. At the same time the lug 14 moves along path B and eventually engages the notch 22. The pivot point is therefore again moved closer to the changed centre of gravity than would have been the case had the pivot point not moved.

As the tray 10 tips it passes through the space between the two chassis arms 25 on either side of the wheelbarrow 1. A purpose of the sloped nature of the forward surface 11 is evident from Figure 1. Were the tray 10 to have a cuboid shape then the lower forward corner would engage the ground preventing tipping to the extent allowed by the sloped surface 1 of the present invention.

It can be seen therefore that the discharge of the load can be carried out in a more controlled manner than with a conventional wheelbarrow.

In some embodiments not illustrated, a motor can be included to assist in bringing and maintaining the wheelbarrow 1 in motion. Moreover said motor can also assist in tipping the load from the tray. If desired, the tray 10 can include legs, depending downwardly from the rearward portion of the underside of the tray 10 in order to support the tray 10.

A further feature which may be included is a securing means, to ensure that the loaded tray does not pivot during transportation. The securing means ensures that the tray remains horizontal with respect to the chassis 16. The risk of loss of the load due to unwanted pivoting is reduced.

It will of course be understood that the invention is not limited to the specific details described herein, which are given by way of example only, and that various modifications and alterations are possible within the scope of the invention.

Claims

1. A wheelbarrow, comprising a tray or container in which a load is transported, a wheel-mounted support frame to support the tray, the support frame including two or more wheels to enable the wheelbarrow to be moved, from place to place, the tray having a handle enabling the user to move the wheelbarrow and lift the tray, a primary pivot pair extending laterally from opposite sides of the tray the pivot pair resting on primary pivot supports provided in the support frame, and one or more further pivot pairs sequentially engaging pairwise further pivot supports, located forward of the primary pivot supports, as the tray is tipped to discharge a load.

2A. A wheelbarrow according to Claim 1 wherein, the tray includes one or more legs on which at least a portion of the weight of the tray can be supported.

3A. A wheelbarrow according to Claim 1 or Claim 2, wherein the support frame includes a transverse cross-piece on which the tray rests, and on which the weight of the tray and the load can be supported.

4. A wheelbarrow according to any preceding claim, including securing means securing the tray to the support frame to prevent tipping of the tray when not required.

5. A wheelbarrow according to any preceding claim, where in the forward end of the tray slopes at an angle between the horizontal and the vertical.

6. A wheelbarrow according to any preceding claim, including a motor to drive motion of the wheelbarrow.

7. A wheelbarrow, according to Claim 6, wherein the motor is linked to the tray to tip the tray when discharging a load.

8. A wheelbarrow substantially as herein described with reference to the accompanying drawings.