This invention relates to a foldable framework for supporting a belt conveyor for handling bulk material, and especially a portable or mobile troughed-belt conveyor. Troughed-belt conveyors are typically incorporated into processing plants for bulk material (such as coal, soil, gravel and mineral ores), where they are variously used for feeding, transporting, elevating, and stock piling materials around the processing plant. When the processing plant is required to be readily movable from place to place, either around a site or between different sites, it is often found that the lengths of the troughed-belt conveyors render the plant unwieldy and difficult or impossible to move. This is especially the case when plant is to be moved along public road, where there are legal limits to the maximum permissible overall dimensions of vehicles. There is therefore a requirement for a means to enable troughed-belt conveyors to be readily foldable.

Hitherto, portable and mobile processing plant has incorporated foldable conveyors, but such conveyors have often been awkward or dangerous to fold or deploy; they have often needed assistance from a loading shovel or a crane; and they have often been limited to less than optimum deployed length by shortcomings in the folding mechanisms. In other cases, foldable troughed-belt conveyor frameworks have been either excessively complicated, making them expensive and troublesome, or else so ineffectual that they remain bulky and unwieldy even when in their folded positions.

The present invention therefore seeks to provide an improved design of foldable framework for bulk conveyors.

According to the invention there is provided a foldable framework for supporting a belt conveyor and which comprises: a fixed sloping support frame;

a movable support frame connected to an upper end of the fixed frame via a first universal type connection; a support leg connected at its lower end to the fixed frame via a second universal type connection and connected at its upper end to the movable frame; and, a power operated device mounted on the fixed frame and connected directly or indirectly to the movable frame and operative to cause the movable frame to pivot about said first universal type connection between an operative conveyor-support position in co-operation with the fixed support frame and a laterally displaced inoperative position suitable for storage and / or transport of the framework and a conveyor supported thereby.

The invention therefore provides a novel construction of foldable framework for supporting a bulk conveyor, such as a troughed-belt conveyor, and which is uncomplicated in its construction, and yet which provides for an unusually large ratio between open and closed envelopes. The invention further provides a powered device in the foldable framework for folding and deploying the framework, and also provides a structure which is particularly simple to fold and deploy.

In a preferred arrangement, the movable frame pivots through an angle of at least 80° about the first universal type connection between its operative and inoperative positions.

Preferably, an additional support leg is provided for the movable frame and which is connected at its lower end to the fixed frame via a third universal type connection. The additional support leg may comprise a telescopic arrangement which can be locked in an extended position to support the movable frame in its operative position, but which can be unlocked and then caused to shorten its length as the movable frame is pivoted to the inoperative position under the action of the power operated device and the first mentioned support leg.

The upper ends of the first mentioned support leg, and of the additional support legs, also may be connected via universal type connections at their upper ends to the movable frame.

The universal type connections provided in the framework according to the invention may comprise any convenient means, such as universal joints, loose fit pivots and elastomeric bearing joints.

In a preferred embodiment, the relative lengths of the movable frame and the first mentioned support leg, and the distances apart and dispositions of the various universal type connections are so arranged that: in the deployed position, the fixed frame and the movable frame are constrained to be aligned, end to end, to form a continuous straight upwardly-sloping conveyor framework whose overhanging portion is at least partially supported by the support leg; as the support leg and the movable frame move to the inoperative or folded position, the movable frame is constrained to swing laterally about its first universal type connection to the fixed frame, and simultaneously rolls about its general longitudinal axis; and, when the movable frame reaches the folded position, the movable frame makes an angle of approximately a right angle with the fixed frame, when viewed from above, and it has simultaneously twisted about its general longitudinal axis also through approximately a right angle relative to the fixed frame, so that those faces of the frame which were its sides in the deployed or operative position are now its uppermost and lowermost faces.

One embodiment of foldable framework according to the invention will now be described in detail, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a perspective illustration of the framework in its unfolded, operative position suitable for

supporting an inclined belt-type conveyor; and.

Figure 2 is a similar perspective view, but showing the framework in its folded, inoperative position.

Referring now to Figure 1, there is seen a fixed base framework 1 which rigidly supports a length of sloping conveyor framework 2, at the uppermost end of which is a first universal joint connection 3 to a second length of sloping conveyor framework 4. The outer end 5 of the framework 4 is supported and located by a pair of supporting legs 6 and 7, leg 6 being a simple rigid strut member and leg 7 being of telescopic construction. (In the position shown, leg 7 is fully extended and secured by means of a through-peg not shown). The supporting legs 6 and 7 are connected at their lowermost ends to the base framework 1 by means of second and third universal joints 9 and 10 respectively. An hydraulic cylinder 8 is pivotally connected across joint 9 between the framework 1 and the leg 6, and forms a power-operated device operable to pivot the movable part of the framework between operative and inoperative positions.

It will be readily apparent that in the position shown, with the hydraulic cylinder 8 and the telescopic leg 7 fully extended, the sloping conveyor frameworks 2 and 4 are aligned end-to-end, and are constrained to slope upwardly towards the furthermost end 5. When equipped with driving and supporting rollers and an endless flexible conveyor belt, this composite framework forms an upwardly sloping conveyor whose overhanging portion is supported by the legs 6 and 7, somewhat in the manner of an inclined tripod.

It should be noted that in the embodiment shown, a cross-beam 13, which is rigidly connected to the conveyor framework 4, must be provided in order to space the supporting legs apart sufficiently to allow the conveyor belt to pass between them.

Referring now to Figure 2, it is seen that the

cylinder 8 has been retracted, causing telescopic leg 7 similarly to retract, and that the framework 4 has been constrained by the rigid supporting leg 6 to swing laterally about its universal joint 3 into a foldable position where it hangs approximately at right angles to the framework 2 when viewed from above. It is further seen that framework 4 has been constrained by the leg 6 to roll or twist about its longitudinal axis through appro imately a right angle during its movement from the working position shown in Figure 1, so that the underside of the conveyor now faces outwardly.

In this position the folded conveyor may be arranged to fit between or around other components of a mobile or portable processing plant in a particularly compact fashion. Thus it is seen that all the objectives of the invention are achieved by means of a singularly uncomplicated linkage.

The invention is not limited to the embodiment hereinbefore described. For example, the universal joints 3, 9 and 10 may be constructed as elastomeric bearings, ball joints or as simple hinges or pivots so mounted as to swing about suitable axes; or the hydraulic cylinder 8 may be a different type of actuator, or it may be connected across different components of the linkage. It should also be noted that the telescopic leg is not fundamental to the invention, and may be omitted entirely from an optional embodiment of the invention.