FIELD OF THE INVENTION

The present invention relates to a portable blending and mixing apparatus for providing a homogenous mixture of various aggregates, cements and additives.

BACKGROUND OF THE INVENTION

Portable blending and mixing plants are frequently used for blending and mixing aggregates and additives in road construction, ground works/civil engineering and environmental stabilisation projects. Such plants typically comprise a feed hopper for receiving materials to be blended and mixed and one or more feed bins or silos containing additives, such as cement, located over a tail end of a belt conveyor for delivering said materials and additives onto the conveyor, a head end of the belt conveyor delivering the mixture of materials and additives into an elevated blending and mixing device, known as a “pugmill”, mounted on the end of the conveyor. The pugmill typically comprises a mixing chamber positioned to receive material discharged from the head end of the conveyor, within which is mounted a pair of counter-rotating mixer shafts having paddles mounted thereon for blending and mixing the material and additives before delivering the mixed and blended material from a discharge end of the mixing chamber onto a stockpile therebeneath. The mixing chamber is typically arranged on the conveyor to have a slight decline, in use, away from the head end of the conveyor to convey material to the discharge end of the mixing chamber under gravity.

The apparatus is typically mounted on a tracked chassis to allow it to be moved around on site.

In order to allow the apparatus to be transported between sites, the conveyor is typically arranged to be lowered with respect to the chassis between an elevated operative position, wherein the conveyor slopes upwardly from its tail end to its head end, and a lowered transport position, wherein the conveyor extends substantially horizontally. The pugmill is typically mounted on the head end of the conveyor to be moved into a transport position resting on top of the conveyor when the conveyor is in its lowered transport position. However, this increases the overall height of the apparatus during transport.

An object of the present invention is to provide a portable blending and mixing apparatus that is mobile on site and more easily moved between sites in a more compact transport configuration.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention there is provided a wheeled or tracked base and a conveyor having a moveable conveying surface extending between a tail end and a head end thereof, the conveyor being mounted upon said base by a support structure adapted to permit adjustment of the angle of inclination of at least an upper portion of the conveyor between an upwardly inclined operative position, wherein the head end of the conveyor is higher than the tail end thereof, and a lowered transport position, a mixing and blending device being supported on the head end of the conveyor via linkage means adapted to facilitate movement of the mixing and blending device between an operative configuration, wherein the mixing and blending device is arranged to receive material discharged from the head end of the conveyor when the conveyor is in its operative position, and a transport configuration, wherein the mixing and blending device is positioned underneath the head end of the conveyor when the conveyor is in its transport position.

In a preferred embodiment the linkage means may comprise at least one forward link arm and at least one rear link arm, said at least one forward link arm and said at least one rear link arm being arranged substantially parallel to one other in a first mode of operation and being pivotally coupled to the head end of the conveyor at respective upper ends thereof and pivotally coupled to the mixing and blending device at respective lower ends thereof such that the mixing and blending device is suspended from the head end of the conveyor via said forward and rear link arms while being permitted swing backwards and forwards with respect to the head end of the conveyor, while the mixing and blending device remains substantially parallel to the conveyor, between a rear position, wherein the mixing and blending device is located beneath the conveyor in its transport configuration, and a forward position, wherein the mixing and blending device extends beyond the head end of the conveyor, drive means being provided for moving the mixing and blending device between said forward and rear positions. The drive means may comprise at least one double acting ram extending between the head end of the conveyor and the at least one rear link arm.

In a preferred embodiment the at least one rear link arm comprises an upper section and a lower section, said upper and lower sections being pivotally coupled to one another, a first locking means being provided for selectively locking together the upper and lower sections of the at least one rear link arm when the mixing and blending device is swung between its forward and rear positions in said first mode of operation, said at least one forward link arm being provided with a second locking means for selectively locking the angular position of the at least one forward link arms with respect to the mixing and blending device when the mixing and blending device is in said forward position, whereby, in use, with the mixing and blending device in said forward position, the first locking means is disengaged and the second locking means is engaged, such that the upper and lower parts of the at least one rear link arm can pivot with respect to one another to allow the mixing and blending device to be pivoted about the upper end of the at least one forward link arm with respect to the conveyor to its operative configuration in a second mode of operation. The at least one double acting ram may act between the head end of the conveyor and the at least one rear link arm at or adjacent the pivotal coupling of the upper and lower sections of the at least one rear link arm. Extension of the ram may act to pivot the upper and lower sections of the at least one rear link arm relative to one another between an extended configuration, wherein the upper and lower sections are substantially aligned in said first mode of operation, and a folded configuration, wherein the upper and lower sections are arranged at an acute angle to one another in said second mode of operation and vice versa.

Stops may be provided for delimiting the pivotal movement of the upper and lower parts of the at least one rear link with respect to one another. The first locking means may comprise a locking pin insertable though aligned apertures in said upper and lower sections of the at least one rear link arm.

The second locking means may comprise a locking pin insertable through aligned apertures in said at least one front link arm and the mixing and blending device.

A third locking device may be provided for selectively locking the mixing and blending device is in its rear position with respect to the conveyor. The third locking device may be adapted to selectively lock the angular position of the at least one rear link arm with respect to the mixing and blending device when in its rear position. In one embodiment the third locking device may comprise a locking pin insertable through aligned apertures in said at least one rear link arm and the mixing and blending device.

The conveyor may be arranged horizontally on the base when in its transport position.

The mixing chamber of the mixing and blending device may be arranged parallel or substantially parallel to the conveyor when in its transport configuration.

Preferably the mixing chamber is inclined with respect to the head end of the conveyor when in its operative configuration.

The mixing chamber may incorporate at least one rotatably driven mixer shaft having paddles mounted thereon is for blending and mixing the mixture supplied to the mixing and blending device from the head end of the conveyor before delivering the mixed and blended material onto a stockpile therebeneath. The mixing and blending device may include a pair of counter-rotating mixer shafts having paddles mounted thereon.

The base preferably comprises a tracked chassis. The support structure preferably extends between said base and the conveyor and is extendable and retractable to vary the inclination of the conveyor between its transport and operative configurations.

A feed hopper may be provided for delivering bulk granular or particulate material onto the tail end of the conveyor. One or more feed bins or silos may be mounted adjacent the feed hopper for delivering further materials or additives onto the conveyor.

Preferably the conveyor comprises an endless belt mounted between elongate beam members.

BRIEF DESCRIPTION OF THE DRAWINGS

A portable blending and mixing apparatus in accordance with an embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:-

Figure 1 is a side view of a portable blending and mixing apparatus according to an embodiment of the present invention with its conveyor in a raised operative position and its mixing and blending apparatus in an operative configuration;

Figure 2 is a side view of the portable blending and mixing apparatus of Figure 1 with its conveyor in in a lowered transport position;

Figure 3 is a side view of the portable blending and mixing apparatus of Figure 1 with its conveyor in in a lowered transport position and its mixing and blending apparatus in a transport configuration;

Figure 4 is a detailed side view of the portable blending and mixing apparatus of Figure 1 with the mixing and blending apparatus in its operative configuration; Figure 5 is a detailed side view of the portable blending and mixing apparatus of Figure 1 with the mixing and blending apparatus in a first stage of movement between its operative and transport configurations; and

Figure 6 is a detailed side view of the portable blending and mixing apparatus of Figure 1 with the mixing and blending apparatus in its transport configuration.

DETAILED DESCRIPTION OF THE DRAWINGS

As illustrated in the drawings, a mobile and portable radial stacking conveyor in accordance with an embodiment of the present invention comprises an elongate endless belt conveyor 10 driven by means of a suitable drive motor to elevate and transfer bulk granular and particulate material between a loading region at a tail end A of the conveyor and a discharge region at a raised head end B of the conveyor. A feed hopper 12 for receiving aggregate material and one or more feed bins or silos 14 containing additives, such as cement, are mounted above the belt conveyor 10 at the tail end A of the conveyor.

The conveyor 10 is mounted on a tracked chassis 16 via a support assembly comprising a telescopic linkage 18, such as one or more hydraulic or pneumatic rams, extending between the chassis 16 and the head end B of the conveyor 10 to permit adjustment of the angle of inclination of at least a portion of the conveyor 10 to adjust the height of the head end B of the conveyor 10 between a raised operative position, shown in Figure 1 , and a lowered transport position, shown in Figures 2 and 3.

A power unit 20, such as a diesel engine, is mounted on the chassis 16 to provide power for the tracks 22 and to provide electrical power, by means of a generator, and hydraulic and/or pneumatic pressure, by means of a hydraulic pump or compressor.

A blending and mixing device 24, referred to in the art as a “pugmill”, is mounted on the head end B of the conveyor 10. The blending and mixing device 24 comprises an elongate box-like mixing chamber 26 within which is mounted a pair of counter- rotating mixer shafts having paddles mounted thereon (not shown) for blending and mixing the material and additives supplied into the blending and mixing device 24 from the conveyor 10 before delivering the mixed and blended material from a discharge opening 28 of the mixing chamber 26 onto a stockpile therebeneath.

The mixing and blending device 24 is suspended from a lower side of the head end B of the conveyor 10 via pairs of substantially equal length and substantially parallel forward 30 and rear 32 link arms on either side of the mixing chamber 26 of the mixing and blending device 24, pivotally coupled to the head end of the conveyor 10 at respective upper ends thereof and pivotally coupled to the mixing and blending device 24 at respective lower ends to define a parallelogram support arrangement allowing, in a first mode of operation, the mixing and blending device 24 to swing backwards and forwards with respect to the head end of the conveyor 10 between a rear position, shown in Figure 6, wherein the mixing and blending device 24 is located beneath the conveyor 10 in its transport configuration, and a forward position, shown in Figure 5 wherein the mixing and blending device 24 extends beyond the head end B of the conveyor.

Respective double acting rams 34 act between the head end of the conveyor 10 and the rear link arms 32, whereby extension and retraction of the rams 34 moves the mixing and blending device 24 between its rear and forward positions when in said first mode of operation, as will be described below.

Each of the rear link arms 32 comprise an upper section 36 and a lower section 38, said upper and lower sections 36,38 of each rear link arm 32 being pivotally coupled to one another such that the rear link arms 32 can be selectively folded between an extended configuration, shown in Figures 5 and 6, wherein the upper and lower sections 36,38 of each rear link arm 32 are substantially aligned, and a folded configuration, shown in Figure 4, wherein the upper and lower sections 36,38 are arranged at an acute angle to one another. Stops 39A,39B are provided for delimiting the extended and folded configurations of the rear link arms 32

First locking means, in the form of first locking pins 40, are provided for selectively locking the upper and lower sections 36,38 of each rear link arm 32 in their extended configuration. Each first locking pin 40 is arranged to be inserted through aligned apertures 41 in the upper and lower sections 36,38 of the respective link arm 32 when upper and lower sections 36,38 of each rear link arm 32 are in their extended configuration, locking the upper and lower sections 36,38 of each rear link arm 32 together and thereby defining said first mode of operation wherein extension and retraction of the rams 34 moves the mixing and blending device 24 between its rear and forward positions while the mixing chamber 26 of the mixing and blending device 24 remains substantially parallel to the conveyor 10.

Second locking means, in the form of second locking pins 42, are provided for selectively locking the angular position of the forward link arms 30 with respect to the mixing and blending device 24 when the mixing and blending device 24 is in its forward position, as illustrated in Figures 4 and 5, wherein the locking pins 42 are arranged to be inserted through aligned apertures 43 in the forward link arms 30 and the mixing and blending device 24, effectively locking the forward link arms 30 to the mixing and blending apparatus 24.

With the mixing and blending device 24 in said forward position, with the second locking pins 42 engaged to lock the forward link arms 30 to the mixing and blending apparatus 24, the first locking pins 40 are disengaged, allowing the upper and lower sections 36,38 of the rear link arms 32 to pivot with respect to one another. In this second mode of operation, extension of the rams 34 folds the upper and lower sections 36,38 of each rear link arm 32 from their extended configuration and folded configuration, thereby effectively shortening the length of the rear link arms and tilting the mixing and blending device 24 with respect to the conveyor 10 about the upper ends of the forward links arms 30 so that the mixing and blending device 24 can be moved to its operative configuration, as shown in Figures 1 and 4.

Further locking pins 44 may be provided to be engaged with aligned apertures 45 in the rear link arms 32 and the mixing and blending device 24 when the mixing and blending device 24 is in its rear position with respect to the conveyor 10 to lock the mixing and blending device 24 in its transport configuration. A safety lock out mechanism may be provided to prevent users trying to operating the rams in the selected mode of operation before the relevant locking pins have been correctly removed and/or engaged. Such mechanism may incorporate a pressure relief valve associated with the rams and/or proximity sensors associated with the locking pins.

The invention is not limited to the embodiment described herein but can be amended or modified without departing from the scope of the present invention.