BULK PARTICULATE MATERIAL CONTAINER

This invention relates to bulk particulate material containers, e.g. for cereals, and has for its object the provision of a bottom door assembly for such a container that can effectively close the bottom of a tubular flexible liner, enabling the liner to be filled from the top and, when required, discharged from the bottom.

According to the present invention, a bottom door assembly for a bulk particulate material container comprises a rectangular base frame, a pair of rigidly-sheeted bottom doors slidable towards each other from respective opposite sides (conveniently the shorter sides) of the base frame, and catches to secure the bottom doors together to enable a lower margin of a tubular flexible liner to be trapped between mating edges of the bottom doors, which mating edges have interleaving rigid lengthwise strips, e.g. two strips on one door and one intermediate strip on the other door, to form a labyrinth-like passage for entrapping the bottom margin of a liner against any leakage of particulate material.

When a container with such a bottom door assembly and a filled liner is required to be emptied, the container can be placed on a hopper, the bottom catches released, and the bottom doors slid apart, for releasing of the entrapped bottom margin of the liner to allow it to open and discharge its contents into the hopper.

One of the doors preferably has a flap extending below and beyond its mating edge to protect any part of the bottom margin of a liner projecting from the labyrinth-like passage, which flap is conveniently pivoted on its respective

door and provided with a projection at each side to ride up a ramp on the other door as the bottom doors come together.

The edge of the flap adjacent its door may conveniently form one of the interleaving strips; and each of the other two interleaving strips may conveniently be formed by a length of wire bent to provide portions for welding to the respective door.

The edge of the flap remote from its door preferably has at least one upstanding projection to form a stop for the leading edge of the lower margin of a liner being fitted. The flap may extend to a lesser amount than the width of its door, but preferably has a width not less than the width of tubular flexible liner to be received by it; and the lateral extent of the flap may be such that it can trap a leading portion of a tubular flexible liner between itself and the leading edge of the other door. An embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which

Figure 1 is an isometric view from above and one end of a bulk particulate material container in accordance with the invention;

Figure 2 is a longitudinal vertical section through the container of Figure 1 , with top lid members swung open and one of the bottom doors partially opened, also showing a tubular flexible liner being inserted;

Figure 3 is a plan view of the base frame of the container of Figures 1 and 2, with both bottom doors partially opened;

Figure 4 is an underneath view of the base frame with the bottom doors positioned as in Figure 3;

Figure 5 is a fragmentary cross-section of the base frame taken from the line V-V of Figure 3;

Figure 6 is a similar view to Figure 5 but taken from the line Vl-Vl of Figure 3; Figure 7 is a fragmentary cross-section taken from the line VII-VII of

Figure 5, with a tubular flexible liner in place and the bottom doors approaching each other;

Figure 8 is a fragmentary cross-section taken from the line VIII-VIII of Figure 5, with the bottom doors in a more advanced state than in Figure 7; and

Figure 9 is a fragmentary cross-section taken from the line VII-VII of Figure 5, but with the bottom doors fully closed.

The container shown in Figures 1 and 2 has a rectangular base frame 10 having integral corner uprights 11 extending below as well as above the base frame, to enable the container to be lifted by a fork-lift truck, with rigid sheeting 12 at the shorter sides (or ends) between the uprights 11. Upstanding from the base frame 10 are rigidly-sheeted longer side frames 13 and ends frames 14 pivoted at different levels to the uprights to enable them to be collapsed in sequence on to the base frame after releasing catches 15. A pair of rigidly-sheeted top lid members 16 are slidable to and over the end frames 14 (as shown in Figure 2) after releasing a lockable catch 17, and the lid members remain attached to and alongside the respective end frames when the latter are collapsed on to the base frame.

The lid members 16 have upstanding formations at the corners of the erected container for location of the lower ends of the corner uprights 11 of

the base frame 10 of a like erected container, and the upper ends of the corner uprights of the base frame have similar formations 18X for location of the lower ends of the corner uprights of the base frame of a like collapsed container. The features described above do not form any part of the claimed invention, being well-known features of collapsible containers and cages in the materials handling industry.

Referring now to Figures 3 to 9, a pair of rigidly-sheeted bottom doors 19, 20, respectively, are slidable towards each other in the base frame 10 from respective opposite sides, i.e. the shorter sides or ends of the base frame, in channels 21 along the other, longer, sides of the base frame, with respective catches 22, 23 to secure the bottom doors together to enable a lower margin 24 of a flexible tubular liner 25 (see especially Figures 2, 5 and 7 to 9) to be trapped between mating edges 26, 27 respectively of the bottom doors formed by square-section tube.

The flexible tubular liner 25 is drawn off from a roller (not shown), is perforated transversely at appropriate intervals, and is pleated lengthwise in similar manner to a refuse bin bag so that each inserted length torn off can be opened out to the sheeting of the sides and closed bottom doors of the container ready to receive particulate material.

The bottom doors 19, 20 are supported from below the channels 21 by rollers 28 mounted alongside the corner uprights 11 of the base frame 10, while they are supported within the channels by rollers 29, 30 respectively on stub axles 31 , 32 respectively mounted on the tubes 26, 27 respectively (see particularly Figures 7 and 8).

In accordance with the present invention, the mating edges 26, 27 of the bottom doors 19, 20 have interleaving rigid lengthwise strips 33, 34, 35 to form a labyrinth-like passage (see Figure 9) for entrapping the bottom margin 24 of the liner 25 against any leakage of particulate material. The rigid lengthwise strip 33 on the bottom door 19 is formed by a length of wire bent to provide portions 36 for welding to the tube 26, and one of the rigid lengthwise strips 34 on the bottom door 20 is likewise formed by a length of wire bent to provide portions 37 for welding to the tube 27. The other rigid lengthwise strip 35 on the bottom door 20 is provided by an upturned edge of a flap 38 extending below and beyond its mating edge 27 from pivots 39 thereon, which flap is provided with a projection 40 at each side to ride up ramps 41 on the other bottom door 19 (see particularly Figure 8) to protect any part of the bottom margin 24 of the liner 25 projecting from the labyrinth-like passage, and the opposite longitudinal edge 42 of the flap 38 is provided with a plurality of upstanding projections 43 to form a stop for the leading edge of the lower margin 24 of a liner being fitted (see particularly Figures 2, 5 and 7).

As can be seen in Figures 3 to 5, the flap 38 extends to a lesser amount than the width of its door 20 between the channels 21 , as long as it has a width not less than the width of tubular flexible liner 25 to be received by it; but the lateral extent of the flap is such that it can trap the leading portion 24 of the liner beyond the labyrinth-like passage between itself and the leading edge 26 of the other door (see Figure 9).

As can be seen by reference to Figure 3, 5 and 7 to 9 a mid-section 44 of the upper flange of each channel 21 is bent down to guide the rigid

lengthwise strips 33, 34, 35 into close interleaving positions (see particularly Figure 9) as the doors 19, 20 reach fully closed position.

When the container with a filled liner is required to be emptied, the container can be placed on a hopper (not shown), e.g. one with formations at its upper corners similar to the formations 18, 18X for location of the bottoms of the corner uprights 11 of the base frame 10, the bottom catches 22, 23 released, and the bottom doors 19, 20 slid apart, for releasing of the entrapped bottom margin 24 of the liner 25 to allow it to open and discharge its contents into the hopper.