Patent Description:
It is known to provide a mower combination in which a first mower unit is located ahead of an agricultural vehicle such as a tractor with two further mower units trailing the agricultural vehicle. The rear mower units may be provided with conveyors for depositing cut crop into a swath or swathes behind the agricultural vehicle. When turning the mower units are raised from a working position to a raised headland position. The intent is that the mower units are raised above the swath or swathes such that the mower units do not disturb the cut crop as the mower units are moved over the swath or swathes. However, in certain case, due to the high mass yields of the cut crop, the swath or swathes of cut crop produced may be so high that overrunning of the swath or swathes with the mower units in the headland position is no longer possible without causing damage to the swath or swathes of cut crop.

<CIT> discloses three working implements, including an emdoiment where the working implements are mowers, connected to a tractor. A first implement is attached to the front of the tractor by a first attachment device. The second and third implements are attached to respective second and third attachment devices located between the front and rear wheels of the tractor. The lifting positions and so the height of the working implements may be altered by actuation of arms connecting the implements to the attachment devices securing the working implements to the tractor.

A mower combination is disclosed in <CIT>.

It is an advantage of the present invention that it also avoids damage to the swath or swathes of cut crop with the mower units in the headland position in such cases.

Other advantages of the present invention will become apparent as discussed below.

According to a first aspect of the present invention, a mower combination comprises an agricultural vehicle together with a front work unit and two lateral work units located behind and to the sides of the front work unit, the front work unit having a front connection to a front of the agricultural vehicle and the lateral work units sharing a rear connection to a rear of the agricultural vehicle, each of the work units depositing a cut crop as a swath, one or more sensors for determining a height of the rear connection above a ground surface, a control unit for controlling a height of the front and rear connections above a ground surface, characterised in that if the height of the rear connection is determined to deviate from a predetermined value, the control unit causes the height of the rear connection to be adjusted towards the predetermined value.

Preferably the mower combination includes a further sensor to detect the presence of crop ahead of the front work unit and in the event of no crop being detected as present the control unit causes one or more of the work units to move from the working position to the headland position.

According to a second aspect of the invention, a method of operation of the mower combination according to the first aspect of the present invention comprises the steps of providing a predetermined set of values to the control unit, providing signals representative of the position of the rear connection, the control unit comparing the signals representing the position of the rear connection against the predetermined set of values and as required signalling the rear connection to be displaced based on this comparison.

Preferably the method further comprises the step of monitoring for the presence of standing crop ahead of the agricultural vehicle, and in the event of no crop being detected as present the control unit causing one or more of the work units to move from a working position to a headland position.

According to a third aspect of the invention, a computer readable program comprises instructions that, when the program is executed on a computer causes the mower combination of the first aspect of the invention to implement the method of the second aspect of the invention.

Reference to terms such as longitudinal, transverse and vertical are made with respect to a longitudinal vehicle axis which is parallel to a normal forward direction of travel.

With reference to <FIG>, a plan view of an agricultural apparatus <NUM> for use in the present invention is shown.

An agricultural apparatus <NUM> comprises an agricultural vehicle <NUM> such as a tractor and a number of work units <NUM>,<NUM>,<NUM> suitable for cutting standing crop, the work units <NUM>,<NUM>,<NUM> being connected to the agricultural vehicle. The work units include a front work unit <NUM> located to the front of the agricultural vehicle <NUM> and two lateral work units <NUM>,<NUM> located behind and to the sides of the front work unit <NUM>, each of the work units <NUM>,<NUM>,<NUM> depositing cut crop as a swath. The front work unit <NUM> is conveniently mounted on a front hitch <NUM> of the agricultural vehicle <NUM>. In a preferred embodiment the work units comprise mowing units.

The lateral mowing units <NUM>,<NUM> are supported from a central chassis by lifting units, for example hydraulic units <NUM>,<NUM>. Each hydraulic unit <NUM>,<NUM> may be used to move a respective lateral mowing unit <NUM>,<NUM> between a working position and a transport position. A headland position may be defined between the working position and the transport position. In the working position the height of each of the lateral mowing units <NUM>,<NUM> above the ground surface <NUM> may be further controlled by operation of the hydraulic units <NUM>,<NUM> between minimum and maximum displacement values, that is across a ground adaptation range.

In <FIG>, a swath <NUM> produced by the front work unit <NUM> is shown. In <FIG> conveyors <NUM>,<NUM> mounted to the rear of the lateral work units <NUM>,<NUM> will direct cut crop inwardly to produce a broader central swath. These swathes are omitted from <FIG> for clarity.

A sensor <NUM> (<FIG>) is provided to determine a displacement or position <NUM> of the rear hitch <NUM>, that is the relative position of the rear hitch assembly in relation to a reference position on the agricultural vehicle (<FIG>).

An operator can control operation of the front and rear work units <NUM>,<NUM>,<NUM> from within the agricultural vehicle <NUM> by use of a suitable user terminal <NUM>. For example the operator can cause each of the work units to move about the central frame a working position to a headland position, can cause each of the lateral work units <NUM>,<NUM> to move between the working position and the transport position. As noted above, the operator can also control the working height of the lateral mowing units <NUM>,<NUM> within the ground adaptation range by use of the hydraulic units <NUM>,<NUM>.

The user terminal <NUM> communicates with an electronic control unit <NUM>. The control unit <NUM> provides signals to control operation of the front and rear hitches <NUM>,<NUM> of the agricultural vehicle <NUM> and provides signals to control operation of the mowing units <NUM>,<NUM>,<NUM> and the conveyor units <NUM>,<NUM>. Conveniently the signals are provided by way of a suitable data communication network <NUM> such as one compliant with the ISOBUS standard (a network in conformance to ISO <NUM>).

The control unit <NUM> may conveniently comprise a single processor located on the agricultural vehicle or its functions may be split between a processor located on the agricultural vehicle and one or more additional processors located on the mowing units <NUM>,<NUM>,<NUM>, the additional processor(s) being in electronic communication with the first processor.

The control unit <NUM> is also able to access a suitable memory <NUM>. The memory <NUM> may take any suitable form and is in electronic communication with the control unit <NUM>.

It is desirable to maintain an even cut of the standing crop. When covering undulating or bumpy terrain an operator has to maintain constant vigilance to maintain a desired working height of the lateral work units <NUM>,<NUM> within the ground adaptation range of the lateral work units <NUM>,<NUM>. If the working height is too low, the lateral work units <NUM>,<NUM> will come into contact with the ground surface. In such a case the cut crop may become contaminated with dirt and/or the lateral work units <NUM>,<NUM> may become damaged. If the working height is too high, there will be uncut areas of crop and so a loss of production in that area. Either outcome is undesirable.

<FIG> shows operation of the agricultural apparatus <NUM> over level ground. <FIG> shows the maximum upper and lower heights <NUM>,<NUM> of the lateral work units <NUM>,<NUM>, that is the ground adaptation range of the lateral work units <NUM>,<NUM> in relation to the agricultural vehicle <NUM> when the hitch <NUM> is in the position <NUM> shown in <FIG>. A predetermined reference value <NUM> for the desired displacement of the rear hitch <NUM> is shown to one side of <FIG>. The predetermined reference value <NUM> is conveniently stored in the memory in any suitable manner such as a database or look up table. In the normal working position over level ground, the predetermined reference value <NUM> corresponds with the actual position <NUM> of the rear hitch <NUM>.

<FIG> shows the agricultural vehicle <NUM> in a raised position with respect to the lateral work units <NUM>,<NUM>. The position or displacement of the rear hitch <NUM> is determined by the sensor <NUM> (step <NUM>, <FIG>). <FIG> shows the position <NUM> of the rear hitch <NUM> is below the predetermined reference value <NUM> but is within an acceptable region of the ground adaptation range of the lateral work units, <NUM>,<NUM>. The difference between the position <NUM> of the hitch <NUM> and the predetermined reference value <NUM> is calculated (step <NUM>). It is then determined whether this difference exceeds a predetermined threshold value (step <NUM>).

The control unit <NUM> may be programmed to take a number of actions as desired. For example if the difference between the position <NUM> of the rear hitch <NUM> and the predetermined reference value <NUM> is determined not to exceed the threshold value the control unit <NUM> takes no action to move the rear hitch <NUM> (step <NUM>). The threshold value is conveniently also stored in the memory <NUM>. For example if the difference between the position <NUM> of the hitch <NUM> and the predetermined reference value <NUM> is determined to exceed the predetermined threshold value the control unit <NUM> can take action to adjust the displacement of the rear hitch <NUM> (step <NUM>). Alternatively, the control unit <NUM> can signal, either visually, audibly or both, to the operator of the agricultural vehicle <NUM> by way of the user terminal <NUM> that the first threshold value has been exceeded so that the operator can take action on their own judgement.

<FIG> shows the agricultural vehicle <NUM> raised further in relation to the lateral work units <NUM>,<NUM>. As seen in <FIG> the lateral work units <NUM>,<NUM> are now operating at or towards an edge of the ground adaptation range. This value or range of values can be defined as a second threshold value or values within the memory <NUM>. <FIG> shows the sequence of steps as the agricultural vehicle travels over an increasing gradient of slope (in <FIG> steps <NUM> to <NUM> are similar to those shown in <FIG>). If no action is taken by the operator or the control unit when a first threshold value is encountered (step <NUM>) the position of the rear hitch <NUM> continues to be compared to the first and second threshold values. In the event of the second threshold value being encountered the control unit <NUM> automatically causes the rear hitch <NUM> to be displaced without input from the operator (steps <NUM>,<NUM>). In the new hitch position, the lateral work units <NUM>,<NUM> are once again i operation comfortably within the ground adaptation range and can more easily be adapted to a desirable working position by the hydraulic units <NUM>,<NUM>. Preferably the rear hitch <NUM> is raised to the new hitch position such that the mower combination is adjusted to the new terrain by the time the lateral work units <NUM>,<NUM> arrive at the new terrain. In this way damage to the lateral work units <NUM>,<NUM> and/or contamination of the cut crop is avoided.

In an alternative embodiment, on detecting the first threshold value the control unit <NUM> may be programmed to alter the height of the rear hitch <NUM> toward the reference value <NUM> and if the second threshold value is then encountered the control unit <NUM> causes the rear hitch <NUM> to be moved more swiftly toward the reference value.

It will be understood that if the opposite slope is encountered, similar steps are undertaken to ensure consistent cutting of the standing crop, that is for the first threshold value the operator may be alerted or the height of the rear hitch <NUM> altered and for the second threshold value the control unit <NUM> automatically alters the height of the rear hitch <NUM>.

It will be understood that this combination of actions is also useful when encountering bumpy terrain so that the work units <NUM>,<NUM> may be controlled to avoid damage and/or ensure a consistent cut of the standing crop when traversing such terrain.

In a further embodiment, a front sensor <NUM> is provided to detect the presence or absence of standing crop ahead of the agricultural apparatus <NUM>. This front sensor <NUM> may be mounted on the agricultural vehicle <NUM> or the front work unit <NUM>. Alternatively an aggregated signal from sensors <NUM> on both the agricultural vehicle <NUM> and the front work unit <NUM> may be used. The control unit <NUM> detects the signal from the front sensor <NUM> (step <NUM> Figure <NUM>) and determines the presence or absence of standing crop head of the front work unit <NUM> (step <NUM>).

If standing crop is detected, the control unit <NUM> takes no action and the work units <NUM>,<NUM>,<NUM> continue to operate in the working position (step <NUM>). If no standing crop is detected the control unit <NUM> causes the work units <NUM>,<NUM>,<NUM> to move to the headland positions (step <NUM>). In this way the when the edge of the standing crop to be processed is reached, the agricultural implement is operated to reach the headland position as soon as possible.

Claim 1:
A mower combination comprising an agricultural vehicle (<NUM>) together with a front work unit (<NUM>) and two lateral work units (<NUM>,<NUM>) located behind and to the sides of the front work unit (<NUM>), the front work unit (<NUM>) having a front connection (<NUM>) to a front of the agricultural vehicle (<NUM>) and the lateral work units (<NUM>,<NUM>) sharing a rear connection (<NUM>) to a rear of the agricultural vehicle (<NUM>), each of the work units (<NUM>,<NUM>,<NUM>) depositing a cut crop as a swath (<NUM>), one or more sensors (<NUM>) for determining a height of the rear connection (<NUM>) above a ground surface, a control unit (<NUM>) for controlling a height of the front and rear connections (<NUM>,<NUM>) above a ground surface, characterised in that if the height of the rear connection (<NUM>) is determined to deviate from a predetermined value, the control unit (<NUM>) causes the height of the rear connection (<NUM>) to be adjusted towards the predetermined value.