Land vehicles – Wheeled – Extensible
Reexamination Certificate
1999-09-30
2001-12-11
Johnson, Brian L. (Department: 3618)
Land vehicles
Wheeled
Extensible
Reexamination Certificate
active
06328331
ABSTRACT:
This invention relates to wheelbarrows for heavy duty use, for example in the building trade. Such wheelbarrows may be used for carrying bricks or other building blocks, for carrying concrete or cement, or merely for carrying rubble.
Wheelbarrows need to be transported to and from building sites at the start and finish of a job. Also, where a job lasts for more than one day, if the site is not secure against theft, then it may also be necessary to remove wheelbarrows from the site when work has finished for the day and to transport them back to the site for the start of work the next day. Conventional wheelbarrows have quite long frames measured from handle end to wheel end, and they therefore take up a lot of space on a van or other transport.
It may happen that when wheelbarrows need to be transported there is insufficient space on whatever transport happens to be available at the time. Of course, a van or other transport can make an additional trip to pick up any remaining wheelbarrow(s) that could not be taken on the first trip, However, this is clearly unsatisfactory, not only because it is a waste of the drivers time and increases transport costs, but also because it may be necessary to pay a man to guard wheelbarrows awaiting the return of a driver to pick them up. For the reasons mentioned above, it may be cheaper to abandon one or more wheelbarrows at a building site than to return to collect them. It will be apparent from the above explanation that there is a great need for a heavy duty wheelbarrow which can be collapsed from a bulky “ready-for-use” position to a space saving position in which it can be stowed.
However, in spite of the obvious need for a heavy duty collapsible wheelbarrow, the inventor has not seen such a wheelbarrow offered for sale,
The only currently available collapsible wheelbarrows known to the inventor are of lightweight construction, and have a collapsible container portion made of a deformable plastics material, or of canvas. These wheelbarrows are readily convertible between collapsed and “ready for use” positions, but they are designed for use in the garden, for example for carrying leaves, grass cuttings or other lightweight items. A wheelbarrow of the construction just described would very soon be destroyed if used on a building site.
In contrast to the above currently available collapsible wheelbarrows, the present invention is particularly concerned with a heavy duty collapsible wheelbarrow having a frame (including, for example, a wheel and a pair of handles), and a container (sometimes referred to in the art as a tray or bucket), the container being securable to the frame in a “ready for use” position, and being releasable from this “ready for use” position to enable the wheelbarrow to be collapsed. One problem with such wheelbarrows is that of securing the container firmly and rigidly to the frame in such a way that the wheelbarrow can rapidly be collapsed and erected, and it is believed that the reason that heavy duty collapsible wheelbarrows are not available for purchase is that nobody has yet found a satisfactory solution to this problem.
One could use a number of nuts and bolts. This would be effective in as much as it would provide a rigid and secure construction in use, but it has many disadvantages. For example, nuts and bolts are readily lost; one or more would be needed; care would be needed to ensure that the nuts were securely tightened, and the process would be time consuming. Also, the heads of the bolts, and/or the nuts, would be likely to become covered in mud or concrete making access to them difficult. The threads of the nuts or bolts would also be susceptible to mechanical damage and rust. It is clear from the above that the use of fasteners such as nuts and bolts would be entirely unsatisfactory in a wheelbarrow intended for use in the building trade.
Instead of nuts or bolts one could use pins adapted to be slid through holes in the container and through corresponding holes in the frame. This would enable the wheelbarrow to be erected and collapsed much quicker, but it would have important disadvantages. Firstly, the attachment of the container to the frame would not be as rigid as with nuts and bolts, and, during use of the wheelbarrow, relative movement would occur in the region where the pins pass through the holes in the frame and in the container. This movement would eventually lead to wear of the pins and of the parts through which they pass. Secondly, the pins would readily be lost. If the pins were to be hung on chains attached to the frame to prevent them from being misplaced, the chains would soon be broken during heavy work in the building trade. Further, it would become difficult to remove the pins and to re-insert them as the wheelbarrow becomes covered in mud, concrete, cement etc.
An aim of one aspect of the present invention therefore is to provide an improved way of securing the container to the frame which overcomes the disadvantages described above.
According to this aspect of the invention there is provided a heavy duty collapsible wheelbarrow comprising a frame, a container and means for securing the container to the frame in a “ready for use” position, the container being releasable from the “ready for use” position to enable the wheelbarrow to be collapsed, in which wheelbarrow the means for securing the container to the frame includes a fastening mechanism which is movable between a released position and a locking position and in which a tensile or compressive force acting on a member of the mechanism progressively increases as the fastening mechanism is moved from the released position towards the locking position.
In a preferred embodiment the fastening mechanism is an over-center mechanism and the tensile or compression force acting on the member progressively increases to a maximum as the mechanism is moved from the released position, after which the mechanism snaps to a stable locking position.
In another embodiment the tensile or compressive force acting on the member of the fastening mechanism progressively increases up to the locking position and the mechanism is held in the locking position by a catch.
The fastening mechanism of a preferred wheelbarrow according to the invention (described in detail below) allows fastening of the container to the frame to be achieved very quickly indeed, for example in between ten and thirty seconds depending on how experienced the user is. There are no nuts, bolts, or pins which could become lost or damaged, and no tools of any kind are required. None of the operative parts of the fastening mechanism lie inside the container to be covered in material such as concrete carried inside the wheelbarrow.
According to another aspect of this invention there is provided a heavy duty collapsible wheelbarrow having a frame, and a container, the container being securable to the frame in a “ready for use” position, and being releasable from this “ready for use” position to enable the wheelbarrow to be collapsed, the frame comprising two parts, one of which carries a wheel for supporting the wheelbarrow on the ground, and the other of which carries a pair of handles used for lifting and wheeling the wheelbarrow, the two frame parts being either hinged together, or being detachably connected together, and both parts of the frame serving in use to support the container.
According to yet another aspect of this invention there is provided a heavy duty collapsible wheelbarrow having a frame and a container, the container being securable to the frame in a “ready for use” position, and being releasable from this “ready for use” position to enable the wheelbarrow to be collapsed, the frame having two crossbars spaced apart in the longitudinal direction of the wheelbarrow so that there is a rear crossbar and a front crossbar, at least one longitudinal bar being secured to the underside of the container, the front crossbar co-operating with the container during assembly of the wheelbarrow to define a forward end position of the container on the frame, and the rear cro
Ipsolom LLP
Johnson Brian L.
Klebe G B
LandOfFree
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