EP3466626A1

EP3466626A1 - Control system and method for a mobile material container or mixer

Info

Publication number: EP3466626A1
Application number: EP18198852.8A
Authority: EP
Inventors: Nicholas Humpish
Original assignee: Hymix Ltd
Current assignee: Hymix Holdings Ltd
Priority date: 2017-10-06
Filing date: 2018-10-05
Publication date: 2019-04-10
Also published as: GB201716394D0

Abstract

A sedimentitious/cementitious container or mixer assembly comprising a drum (106) for receiving and agitating a load of sedimentitious/cementitious material, said container or mixer assembly further comprising an engine, a drum drive means (44) permanently engaged with said engine, and a controller (110) coupled to said drum drive means (44) and configured to selectively stop and start rotation of said drum (106) according to a predetermined cycle and/or predetermined parameters and/or one or more command signals whilst said engine is running.

Description

Field of the Invention

This invention relates generally to the field of mobile sedimentitious/cementitious material containers and/or mixers, and, more particularly to a control system and method for controlling a rotatable mixing drum of a mobile sedimentitious/cementitious material container or mixer.

Background of the Invention

It is known to provide vehicles or trailers that include containers/drums for mixing or holding sedimentitious/cementitious materials, such as concrete, mortar, floor screed or the like. Ready-mix concrete, for example, is concrete that is manufactured in a factory or batching plant, according to a set recipe, and then delivered to a work site, by truck-mounted in-transit mixers. Referring to Figure 1 of the drawings, a typical in-transit mixer, mounted on a truck 10, comprises a rotatable drum 12 mounted between front and rear supports 14, 16 defining a frame on the rear flatbed of the truck. The drum 12 has a longitudinal axis A and is mounted at an angle with its axis A around 10-15° relative to the horizontal axis defined by the flatbed. The drum 12 is closed at the lower end (nearest the truck chassis 10a) and has an opposing open end, and the assembly includes, at least in some cases, a feed in/feed out device 189 for feeding concrete into, and removing concrete from, the drum 12 via the open end. It will be appreciated that other components of a frame for fixing the drum to a vehicle/trailer may also be included, as well as components such as mud guards, side guards and lamp assemblies. The general construction of such frames/components are known to a person skilled in the art and need not be described herein in detail. The frame and other assembly components will typically be formed of steel, but it will be appreciated that other suitable materials can be used.
In-transit mixers are specifically designed to deliver a pre-mixed load of concrete or mortar, and they include mechanisms that prevent the product from separating during transit so that the quality is maintained to the point of placement at the job site. Thus, the drum 12, conventionally, has a number of blades which are attached to the inner surface of the drum so as to form one or more helices that run the length of the drum, wherein the drum is used to agitate and mix the components of a concrete mixture. The drum is driven by a motor within a driveline that is coupled, via a power take off shaft, between the vehicle engine and the drum. Thus, drum drive motor is permanently engaged with the vehicle engine. A manual control system is utilized to stop and start rotation of the drum. Thus, it is usual for the drum is conventionally set to rotate whilst the vehicle is in motion, and left in this state during an entire journey and also whilst the truck is waiting on site to be unloaded.
The speed of the drum is linked to the speed of the engine speed which is, of course, constantly changing throughout a journey. Thus, the drum may be rotated at an unnecessarily high speed (according to the requirements of the load). Furthermore, the initial drum speed is set by the driver, according to their own judgement, and can often be set far too high due to lack of experience/training, as it is set when the engine is idling. Once the truck is mobile, the engine speed may be up to three times that at idle, which results in the drum turning up to three times faster than it needs to during at least part of the journey to site.
As a result, known systems lead to a wastage of fuel and energy, and also result in unnecessary wear and tear on the drum and its drive means. It is known to provide a controller configured to adjust the control signals transmitted to the hydraulic pump of the above-mentioned driveline to control the speed of the drum to compensate for changes in engine speed. It is also known to provide a controller that provides a plurality of selectable settings such that the driver can select a specific drum rotation speed for travelling to the site and waiting on site. However, as the drum drive means is permanently engaged with the vehicle engine, the drum will always be rotating whilst the engine is running unless the driver manually intervenes. This utilizes unnecessary fuel and also results in unnecessary wear and tear on the drum and drum drive means. Furthermore, rotation of the drum whilst the vehicle is travelling at speed can cause the vehicle to be unstable, which clearly has safety implications.

Summary of the Invention

Aspects of the present invention seek to address at least some of these issues and, in accordance with a first aspect of the present invention, there is provided a sedimentitious/cementitious container or mixer assembly comprising a drum for receiving and agitating a load of sedimentitious/cementitious material, said container or mixer assembly further comprising an engine, a drum drive means permanently engaged with said engine, and a controller coupled to said drum drive means and configured to selectively stop and start rotation of said drum according to a predetermined cycle and/or predetermined parameters and/or one or more command signals whilst said engine is running.
Thus, rather than just controlling the speed of rotation of the drum whilst the engine is running, the controller of the present invention actually facilitates stopping and starting the drum rotation according to a predetermined cycle and/or predetermined parameters and /or one or more command signals. As a result, the wear and tear on the drum assembly can be minimised, fuel can be saved without compromising the homogeneity of the load and, in many cases, the overall stability of the assembly can be improved.
In an exemplary embodiment of the invention, the controller may comprise a plurality of selectable modes of operation, each mode defining a different predetermined cycle and/or set of parameters for controlling rotation of said drum. Thus, for example, the controller may define a timed mode, in which the ratio of rotation time to non-rotation time is set against a timeline (or in terms of numbers of rotations). For example, the controller may define a predefined cycle mode defining a ratio of drum rotation to non-rotation, optionally against a timeline (although numbers of turns may also be used to define the cycle. In this case, the ratio of drum rotation to non-rotation may be at least 1 to 3, e.g. 1:3 minutes, i.e. the drum rotates for 1 minute and then stops for 3 minutes before rotating again for 1 minute, and so on. In an exemplary embodiment, this ratio may be approximately 1:5 minutes. In this case, the controller may be configured to generate a control signal each time a change of state of the drum is scheduled (i.e. rotation to non-rotation or vice versa). The control signal may be configured to cause the drum to start or stop rotating according to the schedule. Alternatively, the control signal may be configured to generate a driver prompt (e.g. an audible and/.or visual prompt) to act as guidance, allowing the driver to make the final decision as to whether or not to change the state of the drum at any particular moment, depending on driving and/or truck parameters and conditions. An input means (e.g. a button) may be provided and configured to enable the driver to selectively generate a command signal configured to cause the required change of state of the drum.
The controller may, additionally or alternatively, define a variable cycle mode in which it receives one or more assembly parameters and controls operation of said drum according to said one or more parameters. These one or more parameters may comprise or include engine speed. Thus, the controller may be configured to cause the drum to rotate when the engine speed is idling and/or below a predetermined threshold (indicating that the mixer truck is stationary at, for example, traffic lights or otherwise stationary or travelling at very low speed), and cause the drum to stop rotating when the engine speed is above a predetermined threshold. Thus, in the case where the assembly is an in-transit container or mixer truck, the controller may be configured to cause the drum to rotate when the truck is stationary and/or travelling at a speed lower than a predetermined threshold, and cause the drum to stop rotating when the truck is travelling at a speed greater than a predetermined threshold.
Once again, the controller may be configured to generate a control signal each time a change of state of the drum is required (i.e. rotation to non-rotation or vice versa). The control signal may be configured to cause the drum to start or stop rotating according to the sensed parameters. Alternatively, the control signal may be configured to generate a driver prompt (e.g. an audible and/.or visual prompt) to act as guidance, allowing the driver to make the final decision as to whether or not to change the state of the drum at any particular moment, depending on driving and/or truck parameters and conditions. An input means (e.g. a button) may be provided and configured to enable the driver to selectively generate a command signal configured to cause the required change of state of the drum.
The controller may, additionally or alternatively, be configured to receive data representative of said load and cause said drum to stop and start rotating in a cycle according to one or more characteristics of said load. Thus, some loads may require more (or more frequent) agitation than others in order to maintain their homogeneity, and the controller may be configured to account for this, either by means of a manually or automatically selectable mode.
The controller may also include a (manually or automatically) selectable waiting mode, wherein when said engine has been idling for a predetermined period of time, the drum is caused to stop rotating and the engine is switched off, and the controller is configured to periodically re-ignite the engine and cause the drum to rotate for a predetermined period of time and/or number of rotations before causing the engine to be switched off again.
Yet again, and in respect of both of the above-mentioned modes, In this case, the controller may be configured to generate a control signal each time a change of state of the drum is scheduled (i.e. rotation to non-rotation or vice versa). The control signal may be configured to cause the drum to start or stop rotating according to a schedule, cycle or sensed parameters. Alternatively, the control signal may be configured to generate a driver prompt (e.g. an audible and/.or visual prompt) to act as guidance, allowing the driver to make the final decision as to whether or not to change the state of the drum at any particular moment, depending on driving and/or truck parameters and conditions. An input means (e.g. a button) may be provided and configured to enable the driver to selectively generate a command signal configured to cause the required change of state of the drum.
It is understood that starting a drum rotating and/or starting an engine, without warning, may be distracting and any unplanned changes in machine state can be disconcerting and/or cause potential safety issues. Therefore, in the case where the controller generates control signals configured to automatically cause the drum to stop or start rotating, the controller may further comprise warning means for generating a visual and/or audible warning when the drum state changes from rotating to non rotating and/or vice versa. Furthermore, and whether the controller causes automatic stopping and starting of the drum rotation, or whether the controller simply generates driver prompts to which the driver can respond and cause the drum state to change as required, the apparatus may comprise means for starting or stopping rotation of the drum by substantially uniformly increasing or decreasing the power to the hydraulic motor of the driveline so as to ramp up/or down the change of state of the drum and minimise the potential impact thereof.
The assembly may for example, comprise an in-transit mixer truck. However, the assembly may alternatively comprise a static re-mixer assembly.
In accordance with another aspect of the present invention, there is provided a controller for an assembly substantially as described above, the controller being couplable to the drum drive means and configured to selectively stop and start rotation of the drum according to a predetermined cycle and/or predetermined parameters whilst the engine is running.
In accordance with yet another aspect of the present invention, there is provided a method of controlling a drum drive means of an assembly substantially as described above, the method comprising, whilst the engine is running, stopping and starting rotation of the drum according to a predetermined cycle and/or predetermined one or more parameters.
Thus, the present invention provides an assembly including a controller designed to actively intervene in the control of the hydraulic pump to minimise/optimise drum rotation by intermittently stopping the drum from rotating altogether under certain circumstances. In an exemplary embodiment, the controller may adopt a ratio of turning to not turning against a timeline, e.g. allowing the vehicle to travel without drum rotation for, say, 5 minutes, and then causing the drum to rotate for 1 minute to 'remix' or agitate the contents of the drum and ensure its homogeneity is maintained), before stopping the drum for a five minutes once again. Other exemplary embodiments may control the rotation/non-rotation of the drum by assessing the drive status of the vehicle. For example, the controller may be configured to cause the drum to rotate when the engine is idling (or below a predetermined speed), indicating that the vehicle has, for example, stopped at traffic lights, and cause the drum to stop rotating when the vehicle is travelling at a speed above some predetermined threshold.
In-transit mixers have a high centre of gravity and so are prone to leaning when they turn a corner. When the drum is rotating, the centre of gravity of the vehicle is offset, thus making the truck even more prone to leaning when turning in a particular direction and the load will continue to take the centre of gravity further from the centre line of the truck, further exacerbating the tendency to lean, increasing the likelihood of the truck tipping over. As a result of aspects of the present invention, this tendency can be greatly reduced.
In another embodiment, the control system may be configured to adjust the drum's rotational position to reduce the height and / or lateral offset of the centre of gravity of the drum and its contents. The drum when rotating will cause the load in the drum to be displaced in the direction of the rotation, which will cause the centre of gravity of the load to shift. In a vehicle that is travelling on highway and is required to negotiate traffic and follow the layout of the road, the route and the changing cambers, a centralised and lower centre of gravity will reduce the chance of the vehicle becoming unstable and therefore reduce the likelihood of the truck tipping over. The system may thus be configured to finish a rotating cycle by reversing the rotation of the drum returning the load to a position which reduces either or both the lateral offset and /or the height of the centre of gravity, either by means of a predetermined period of time, a predetermined number of degrees of rotation, or by the measurement of the hydraulic pressure in the driveline to determine when the load is in a more stable condition.
The materials in the load tend to be abrasive, and their abrasive effect is greatly increased when the drum is rotating. Drums are expensive to replace and often require time out of service whilst being repaired or replaced. By not turning the drum constantly, but only turning it periodically, this wear is reduced and allows the drum to last longer and/or be made with less material, thus reducing the tare weight of the overall vehicle. This, in turn, reduces the payload and reduces the cost of transport and/or the number of truck journeys required.
These and other aspects of the present invention will be apparent from the following specific description.

Brief Description of the Drawings

Embodiments of the present invention will now be described, by way of examples only, and with reference to the accompanying drawings, in which:

Figure 1 is a schematic diagram illustrating an in-transit mixer according to the prior art;
Figure 2 is a diagram illustrating a driveline for an in-transit mixer truck;
Figure 3 is a schematic diagram illustrating an in-transit mixer according to an exemplary embodiment of the present invention;
Figure 4 is a schematic block diagram illustrating a controller according to an exemplary embodiment of the present invention; and
Figure 5 is a schematic flow diagram illustrating a process flow embodying a method according to an exemplary embodiment of the present invention.

Detailed Description

Referring to Figure 2 of the drawings, a known driveline for driving the drum of an in-transit mixer is illustrated, and comprises a power take off (PTO) shaft 40 connected to a hydraulic pump 42 that enables the speed and direction of the drum to be altered in accordance with control signals received via traditional control cables. The hydraulic pump 42 is coupled to a hydraulic motor 44 via high pressure hoses 46, and the hydraulic motor 44 is connected to a gearbox 48 that is coupled to the drum. Also illustrated in the assembly of Figure 2 are a hydraulic filter 50 and return hoses 52, and the assembly also includes a direct drive water pump 54.
The PTO shaft 40 is driven by the mixer truck engine, and is typically always engaged, regardless of whether or not the transmission is engaged. This type of power take off will be well known to a person skilled in the art, and need not be described further herein. In some embodiments, it is known for the pump to be driven by other means, either a separate engine, a close coupled arrange,emt or possibly an electrically driven PTO, whether permanently or manually/automatically selectably engaged.
Referring additionally to Figure 3 of the drawings, a concrete mixer vehicle 100 is illustrated, comprising a cab 102 and a drum bed 104 on which is mounted the rotatable drum 106. The rotatable drum 106 is driven by the motor 44 (via the gearbox 48), also referred to herein as the 'drum drive means'. A controller 110 is coupled to the motor, and configured to control rotation of the drum 106, as described in more detail hereinafter. Within the cab 102 there is a monitoring system 118 comprising a computing device containing processing circuitry, a display and an output interface. An input/output controller is connected to an input means (e.g. a keyboard) to allow a user to make inputs to the monitoring system 118.
Referring to Figure 4 of the drawings, the controller 110 comprises a power processing unit (PPU) 400 coupled to the motor 44, a control unit 402 and a sensor unit 404. The control unit 402 receives data from the sensor unit 404 and input commands from the monitoring system 118, and controls the power processing unit 400 accordingly. The PPU 400 generates signals configured to selectively operate the motor 44 and, therefore, rotate the drum 106. The sensor unit 404 may, for example, monitor speed/position of the drum 106, tilt angle, etc. Sensor units of this type will be familiar to a person skilled in the art and need not be discussed in any further detail herein.
Referring to Figure 5 of the drawings, a flow diagram is shown, illustrating a drum rotation control method according to an exemplary embodiment of the present invention. In general, and as explained above, the control unit 402 generates signals to selectively stop and start rotation of the drum 106, according to signals received from the PPU 400. The PPU 400 generates such signals in accordance with input commands from the monitoring system 118, which offers one or more selectable setting to enable such automatic stopping and starting of the drum rotation without further intervention from the driver/operative. Thus, the method starts with the selection (at step 502) of a PPU setting. Such selection may be made by the driver/operative or it may be made as a result of data received from the material (e.g. concrete) batch plant about the load, thereby enabling selection of the optimum setting/program for the type of mix loaded on the truck, or may be determined by the system itself based on data received from the sensor unit 404.
For the purposes of the following description, three selectable settings are provided, namely "Timed", "Variable (with truck operation)" and "Optimum (based on mix loaded)".
If the "Timed" setting is selected, the PPU 400 is programmed to adopt a ratio of turning to not turning against a time line. This ratio/timeline may be selected according to the precise nature of the mix loaded on the truck, but this is not essential. Thus, once the truck is started, the PPU 400 is programmed to turn the drum for a predetermined period of time, at a constant speed, and then not turn the drum for a period of time. Purely by way of example, then, the PPU 400 may be configured to allow the truck to travel for 5 minutes without turning the drum, and then cause the drum to rotate at a constant speed for 1 minute, before stopping the drum for 5 minutes again, and so on. This has the result that the drum is periodically rotated to 'remix' or agitate the contents and ensure its homogeneity is maintained without needing to rotate the drum continuously, which uses excessive fuel, results in excessive wear and tear of the drum and causes the truck to be unnecessarily unstable for large parts of the journey. Whilst this process may be performed entirely automatically, in an alternative embodiment, it may be that the system issues an audible visual or combined signal to the driver / operative that serves as a prompt or reminder to start and /or stop a period of mixing. This would give the driver the option of the optimum time to commence and / or stop the drum rotation cycle such that the driver could evaluate the dynamics of the truck and the road conditions, and such that the changed status of the drum when travelling would not negatively affect the stability or drivability of the vehicle. Such changes have been possible in the past using mechanical controls, and changes in drum drive resulting from changing engine speeds associated with driving have been an intrinsic feature of rotating drum mixers historically, so whilst the possibility of changing drum drive status (rotating or not rotating) may be seen as a newly identified 'risk' in the changing dynamics of the truck movement, the system in its implementation will reduce this risk overall when compared with historic and current systems. In response to a prompt, the driver may be able to provide some form of input (e.g. press a button) to generate a command signal which is configured to stop or start rotation of the drum, as required.
Once the truck arrives on-site, a setting may be selected (automatically or otherwise) that causes the drum rotation function to enter a so-called "on-site waiting mode", which will be described in more detail hereinafter.
If the "Variable" setting is selected, the PPU 400 is configured to rotate the drum 106 in accordance with road conditions and truck operation. Sensors in the above-mentioned sensor unit are utilised torn monitor the drive status of the truck, and sensor signals obtained therefrom are then used by the PPU to control the rotation of the drum. A number of different truck parameters and conditions, or changes therein, may be used to control the drum rotation. For example, this setting may be configured to rotate the drum when the truck is stationary (at, for example, traffic lights), and stop the drum from rotating when the truck is mobile. Indeed, further control could be added, whereby the drum is only rotated when the truck is stationary or below a predetermined speed, thus ensuring that when the truck is travelling above some predetermined speed, the drum is stationary, thus avoiding the inherent instability that a rotating drum can otherwise cause. In an alternative embodiment, the drum may be configured to rotate only if the engine speed is above or below a predetermined value. In these cases, a timing mechanism may also be incorporated to ensure that, if the drum is stationary for longer than a predetermined period of time, the drum is caused to rotate for a short period (irrespective of the status of the truck and/or its speed of travel, just to ensure that the load is re-mixed or agitated to ensure that its homogeneity is maintained.
In yet another exemplary embodiment, the "Optimum" setting may be selected (manually or automatically) according to the specific requirements of the type of material mix that is loaded on the truck. In this case, the parameters and settings for rotating the drum may be specified to ensure that the drum is rotated sufficiently often to maintain the homogeneity of the mix, whilst minimising unnecessary rotation whilst the truck is in transit. Once again, this may be achieved, for example, by setting a ratio of rotation to non-rotation (against a timeline or numbers of turns, say) according to the maximum time the load can go without being mixed or the minimum amount of agitation required in any predetermined period.
The PPU 400 may also have a setting for use when the truck is stationary, and waiting on-site for use. In current systems, during such times, the truck engine is typically allowed to remain running and the drum is rotated accordingly. However, in accordance with an exemplary embodiment of the invention, the PPU may be configured to enter the "Waiting" setting (either manually or by monitoring the outputs from the sensor unit to determine that the truck has arrived on-site and is waiting for use). In the "Waiting" mode, the PPU 400 first causes the drum to stop rotating, and then causes the engine to be switched off. A timing mechanism may be utilised to cause the PPU to re-fire the engine and rotate the drum for a predetermined period of time every so often (e.g. every 5 minutes), following which, it once again stops the drum from rotating and switches the engine off again.
As explained above, and in respect of all of the above-described modes, the controller may be configured to generate a control signal each time a change of state of the drum is required. The control signal may be configured to cause the drum to start or stop rotating according to the schedule, thus facilitating entirely automatic stopping and starting the of the drum rotation in accordance with a predetermined cycle or predetermined parameters . Alternatively, the control signal may be configured to generate a driver prompt (e.g. an audible and/.or visual prompt) to act as guidance, allowing the driver to make the final decision as to whether or not to change the state of the drum at any particular moment, depending on driving and/or truck parameters and conditions. An input means (e.g. a button) may be provided and configured to enable the driver to selectively generate a command signal configured to cause the required change of state of the drum.
Thus, aspects of the present invention provide a controller programmed to provide one or more settings that will automatically stop and start the drum without further intervention from the driver, or will provide prompts to enable the drum to be stopped and started in an optimum manner or cycle. The settings may take account of input data from the truck chassis or the mixer to establish the exact ('optimum') nature of the cycle. This might include data about the engine speed, road speed and/or any changes in these parameters. It may include information about the hydraulic pressure in the mixer drivetrain to determine the nature of the mix and/or may receive data from the concrete batch plant about the load that may allow the selection of an optimum program for the type of mix loaded. The concept may be extended to include control of the engine whilst a container/vehicle is waiting on site. In this case, the controller is configured to turn the engine on and off whilst waiting. After arriving on site and being asked to wait, the system can be configured (either via a manual setting selection or by assessing that the vehicle is in a holding state) to first stop the drum from turning and subsequently shut the engine down. After a period of time, it may automatically restart the engine and then start the drum turning at a predetermined speed for a period of time, before again stopping the drum and shutting down the engine, thus saving fuel and reducing engine noise and (gas or particulate) emissions.
As explained above, in some exemplary embodiments, an audible or visual warning device may be utilized and caused to operate to provide an alert when the engine is about to change state and/or drum rotation is about to begin and/or end.
Whilst the present invention has, to a large extent, been described above in relation to in-transit mixer trucks, aspects of the present invention also apply to static mixers or so-called 're-mixers' that are used to hold ready mixed concrete on a job site until needed. These are typically driven by their own engines and left running all day. Thus, the benefits of the present invention in relation to such assemblies will be similar to those described above in relation to in-transit mixers, in respect of emissions, wear and tear and fuel saving.
It will be apparent to a person skilled in the art, from the foregoing description, that modifications and variations can be made to the described embodiments without departing from the scope of the invention as defined by the appended claims.

Claims

A sedimentitious/cementitious container or mixer assembly comprising a drum for receiving and agitating a load of sedimentitious/cementitious material, said container or mixer assembly further comprising an engine, a drum drive means permanently engaged with said engine, and a controller coupled to said drum drive means and configured to selectively stop and start rotation of said drum according to a predetermined cycle and/or predetermined parameters and/or one or more command signals whilst said engine is running.
An assembly according to claim 1, wherein said controller is configured to generate a control signal to stop or start rotation of said drum, and optionally wherein said control signal is configured to cause said drum to stop or start rotating; and/or wherein said control signal is configured to generate driver prompt data, and optionally wherein said driver prompt data comprises an audible or visual signal.
An assembly according to claim 1 or claim 2 further comprising a manual input means configured to receive an input in response to said driver prompt data, said controller being configured, in response to said input, to generate a command signal configured to cause said drum to stop or start rotating.
An assembly according to any of the preceding modes, wherein said controller comprises a plurality of selectable modes of operation, each mode defining a different predetermined cycle and/or set of parameters for controlling rotation of said drum.
An assembly according to any of the preceding claims, wherein said controller defines a predefined cycle mode defining a ratio of drum rotation to non-rotation, and optionally wherein said ratio of drum rotation to non-rotation is defined against a timeline, and optionally wherein said ratio of drum rotation to non-rotation is at least 1 to 3, e.g. 1:3 minutes or approximately 1:5 minutes.
An assembly according to any of the preceding claims, wherein the controller defines a variable cycle mode in which it receives one or more assembly parameters and controls operation of said drum according to said one or more parameters.
An assembly according to claim 6, wherein said one or more parameters comprise or include engine speed.
An assembly according to any of the preceding claims, wherein said controller is configured to cause the drum to rotate when the engine speed is idling and/or below a predetermined threshold, and cause the drum to stop rotating when the engine speed is above a predetermined threshold.
An assembly according to any of the preceding claims, comprising an in-transit container or mixer truck, wherein said controller is configured to cause the drum to rotate when the truck is stationary and/or travelling at a speed lower than a predetermined threshold, and cause the drum to stop rotating when the truck is travelling at a speed greater than a predetermined threshold.
An assembly according to any of the preceding claims, wherein the controller is configured to receive data representative of said load and cause said drum to stop and start rotating in a cycle according to one or more characteristics of said load; and/or wherein said controller includes a selectable waiting mode, wherein when said engine has been idling for a predetermined period of time, the drum is caused to stop rotating and the engine is switched off, and the controller is configured to periodically re-ignite the engine and cause the drum to rotate for a predetermined period of time and/or number of rotations before causing the engine to be switched off again.
An assembly according to any of the preceding claims, further comprising warning means for generating a visual and/or audible warning when the drum state changes from rotating to non rotating and/or vice versa.
An assembly according to any of the preceding claims, comprising an in-transit mixer truck or a static re-mixer assembly.
An assembly according to any of the preceding claims, wherein said controller is configured to stop or start rotation of the drum by gradually increasing or decreasing the power to said drum drive means; and/or wherein the controller is configured, before stopping rotation of said drum in a first direction, to cause said drum to rotate in the opposite direction
A controller for an assembly according to any of the preceding claims, the controller being couplable to the drum drive means and configured to selectively stop and start rotation of the drum according to a predetermined cycle and/or predetermined parameters and/or one or more command signals whilst the engine is running.
A method of controlling a drum drive means of an assembly according to any of claims 1 to 13, the method comprising, whilst the engine is running, stopping and starting rotation of the drum according to a predetermined cycle and/or predetermined one or more parameters and/or one or more command signals.