TECHNICAL FIELD

The present disclosure relates generally to a vehicle having a body which can be moved relative to another vehicle member and a control system for automatically selecting an operational mode of the body.

BACKGROUND

Load carrying vehicles, including trucks, wheel loaders and the like, are commonly employed during construction and excavation for transporting loads from one point to another. Load carrying vehicles may comprise a body often known as a dump body, for holding material which can be raised relative to the vehicle chassis and tipped about a pivot point to empty any material held therein. The body position may be controlled by one or more actuators, commonly hydraulic, which may move the body between a lowered loading and transport position and a raised tipping position.

A body control device, often known as a hoist control lever, may be conveniently located in the operator cab for actuating the raising or lowering of the body. Commonly known settings or positions for such body control devices relate to the following functions:-

- a "lower" function, in which the hydraulic lifting cylinders, or other actuators are actuated to move the body downwardly under power;

- a "float" function, in which the hydraulic lifting cylinders, or other actuators, are unpressurised and the body is permitted to move down under its own weight;

- a "hold" function, which maintains the body in its current position; and - a "raise" function which actuates the hydraulic lifting cylinders, or other actuators to move the body upwardly under power. The body control device positions for the float and hold functions are usually intermediate to the body control device positions for the lower and raise positions.

The float function may be used during transport with the body resting, for example against the vehicle chassis. The float function may also be used when lowering an empty or partially loaded body. Typically the float function may be selected when the body is close to the fully lowered position. If only the lower function is used, this may result in the body ^slamming' down under power onto the chassis, adversely loading the chassis. The operator may select the float function and then drive away from the dumping site, while the body lowers to the chassis under its own weight .

SUMMARY OF THE DISCLOSURE

The present disclosure therefore provides a vehicle comprising :

a body movable between at least two position;

a hoist system comprising at least one actuator

connected to the body, said hoist system having a plurality of operational modes comprising at least:

a first mode in which the at least one actuator moves the body between the at least two position; and

a second mode in which the body moves under its own weight;

an operator controlled body control device for

selecting the first mode of the hoist system; a control system; and

at least one inertia measurement unit configured as an inclination sensor to provide at least one position signal to the control system relating to a body position of the body;

wherein said control system is configured to automatically engage the second mode of the hoist system if it determines from the at least one position signal that the body position is at a first predetermined body position and the first mode is engaged.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred embodiments of the vehicle and control system of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings in which :

Figure 1 is a side elevation of an articulated load carrying vehicle; and

Figure 2 is a pictorial view of a combined transmission gear select lever and body control device.

DETAILED DESCRIPTION

The vehicle of the present disclosure may be any type of vehicle, in particular a load carrying vehicle, which has a body that may be moved relative to another vehicle member between first and second positions. In this example the body is raised and lowered relative to a chassis. Such vehicles include articulated or non-articulated vehicles. One

exemplary vehicle 10 is illustrated in Figure 1 in the form of an articulated tipper truck.

The vehicle 10 may comprise a first frame 11, in this example a tractor unit, attached to a second frame 12, in this example a trailer unit. The frames 11, 12 may be attached together by a coupling 13. The first frame 11 may comprise an operator cab 14 which houses the operator controls for the vehicle 10. The coupling 13, which may be an articulation joint, may allow each of the first and second frames 11, 12 to be orientated at a different yaw and/or roll angle to the other frame 12, 11.

The second frame 12 may comprise a body 17, such as a dump body, adapted to carry a load. The body 17 may be pivotally attached to a chassis 18 of the second frame 12 at a pivot point. The second frame 12 may further comprise a hoist system 15 which, when activated, may raise the body 17 from a first body position 19, which in this example is a "body down" position resting on the chassis 18, causing it to rotate about the pivot into a second body position 20, which in this example is a "body up" tipping position at an angle to the chassis 18. As the body 17 rotates into the second body position 20, the body 17 may eject some or all of the materials or load from the body 17. The hoist system 15 may also be activated to carry out the reverse operation, in which the body 17 is lowered from the second body

position 20 back to the first body position 19. The body 17 may be any type of container and may be open at the top, fully enclosed or partially enclosed.

In yet another type of vehicle, the body 17 may

comprise the operator cab 14 or another vehicle member which is raised and lowered or otherwise moved relative to the chassis 18, or a different vehicle member.

The hoist system 15 may comprise at least one actuator connected between the body 17 and the chassis 18. One actuator may be provided on each side of the vehicle 10. Alternatively, one or more actuators may be provided

underneath the body 17 or in another configuration. The hoist system 15 may further comprise a pump, driven by the vehicle's power unit (for example an engine), for supplying pressurised working fluid to the actuators. The actuators may be cylinder actuators which provide a fixed length of straight-line motion. Such actuators may comprise a tight- fitting piston movable within a closed cylinder. The piston may be attached to a rod that extends from one end of the cylinder to provide the mechanical output. The cylinder may have a port at each end to admit or return fluid.

The hoist system 15 may be a hydraulic system,

comprising at least one hydraulic actuator. Alternatively, the hoist system 15 may be a pneumatic or electrical system, comprising pneumatic or electrical actuators.

At least one valve, such as a hoist valve, may be used in conjunction with the actuator (s) to control the supply of pressurised fluid to/from the actuator (s) . The hoist valve may be a four-way directional valve. Where the actuators are cylinder actuators, the hoist valve may connect the cylinder ports to the working fluid supply or the return to a fluid tank, depending on the desired direction, if any, of the power stroke. The hoist valve may have a first (Extend) valve position, which causes the actuator to extend. For a cylinder actuator, a first cylinder port may be connected to the fluid supply and the second cylinder port may be

connected to the return to the fluid tank. The hoist valve may have a second (Retract) valve position, which causes the actuator to retract. For a cylinder actuator, the second cylinder port may be connected to the fluid supply and the first cylinder port may be connected to the return to the fluid tank. The hoist valve may have a third (Float) valve position, in which the actuator is unpressurised or under a low pressure. For a cylinder actuator both cylinder ports may be connected to atmospheric pressure, or a source of low pressure, for example to the fluid tank. The hoist valve may have a fourth (Hold) valve position in which the actuator remains pressurised. For a cylinder actuator the actuator may remain pressurised but any flow of the working fluid is prevented.

The vehicle 10 may comprise one or more terrain

engaging means 21,22 in contact with the terrain 23. The terrain 23 may be the ground or any surface on which the vehicle 10 is operated. The terrain engaging means 21,22 may be, for example, tracks and/or wheels which are driven by the vehicle's power unit to enable the vehicle 10 to move along the terrain 23 and the vehicle 10 may comprise any number of terrain engaging means 22. As illustrated in

Figure 1, the first frame 11 may have one pair of first frame ground engaging means 22 and the second frame 12 may have two pairs second frame ground engaging means 21, with one of each pair of ground engaging means 21,22 located on either side of the vehicle 10.

The operator controls may include one or more brake actuators (such as pedals) , a transmission gear select lever 25, one or more body control device 24 (often known as hoist levers) and a steering device. In one embodiment, a single body control device 24 may be mounted on or combined with the transmission gear select lever 25. The body control device 24 may comprise a switch on the transmission gear select lever 25, as shown in Figure 2. The switch may comprise a multi-position rocker switch, which has positions for Lower (L) , Raise (R) and Hold (H) . The Hold position may be ommitted, although in such a case the hoist valve may still have a hold function as described above.

Alternatively, the body control device 24 may comprise a separate lever mounted for pivoting between the various positions .

The vehicle 10 may comprise one or more electronic control units (ECUs) which are configured to monitor

operating parameters and to control operation of various of the vehicle's systems and components. These ECUs will be collectively referred to herein as a control unit. The body control device 24 may be operably connected to provide a hoist signal to the control unit. Each position of the body control device 24 may provide a different hoist demand signal to the control unit. The hoist valve (s) and pump may be operably connected to the control unit and controlled thereby.

The vehicle 10 may further comprise at least one position sensor 26 mounted on the body 17, which is

configured to determine the angle/position of the body 17 relative to the chassis 18 and to provide a position signal relating thereto to the control unit. One position sensor 26 may be mounted on the body 17 and a second position sensor 26 may be mounted on another part of the vehicle 10, for example the chassis 18 to which the body 17 is mounted. If the vehicle 10 is an articulated vehicle, a second position sensor 26 may be mounted on the first frame 11 (tractor unit) . The position sensor may comprise an inertia measurement unit (IMU), which is configured to act as an inclination sensor. The position sensor may be of any type of IMU, for example, piezoelectric, capacitive, potentiometric, Hall effect, magnetoresistive, piezo-resistive or any type of micro-electromechanical system (MEMS) . These sensors generally comprise a "proof" mass. This mass moves relative to the frame of the sensor. That difference in movement between the frame and proof mass is related to its

acceleration and can be measured in a variety of ways:

capacitively, piezo-electrically, and piezo-resistively . A solid object's movement can be fully described by measuring linear acceleration in the x, y, and z directions and angular velocity about the x, y, and z axes

The control unit may determine the angular position of the body 17 relative to the other part of the vehicle, such as the chassis 18 or first frame 11, based on the position signal (s) received from the position sensor (s). Where two position sensors are used, the control unit may compare the position signals received from the two sensors. If the position signals are the same, then the body 17 is in the lowered position. If they are not the same, the control unit may use an algorithm to calculate the relative angular difference between the body 17 and the chassis 18/first frame 11. This relative difference is the "body up" angle. For an articulated vehicle it should be noted that the first and second frames 11,12 may themselves be at different angles and the algorithm may take account of this. GB-A- 2497134 describes how IMUs may be used to calculate the relative angular position of the body in an articulated vehicle, taking account of a number of different scenarios. The contents of this document are incorporated herein by reference .

INDUSTRIAL APPLICABILITY

The vehicle of the present disclosure may be any of a wide range of vehicles, not just those described herein, which have a body 17 which may be raised or lowered or otherwise moved relative to a chassis 18 or other vehicle member. In particular the vehicle 10 may be a tipper truck with a hydraulically controlled pivotable dump body.

When the operator wishes to raise the body 17, or move it from a first body position 19 to a second body position 20 (which may be a a first mode of operation) , he may select the Raise (R) position of the body control device 24. This may provide a first hoist demand signal to the control unit. On receipt of this signal, the control unit may switch the valve (s) of the hoist system to the first valve position. The control unit may also adjust the speed of the vehicle power unit, to run at an appropriate operating speed for driving the pump. This may cause the actuator (s) of the hoist system 15 to extend, thereby raising the body 17, or moving it from the first body position 19 towards the second body position 20. In the case of a tipper system, the act of raising the body 17 may also cause it to pivot, thereby emptying some or all of the materials therein.

When the operator wishes to lower the body 17 from a raised position (which may be a third mode of operation) , for example after it has been emptied or partially emptied, or move it to the first body position 19, he may select the Lower (L) position of the body control device 24. This may provide a second hoist demand signal to the control unit. On receipt of this signal, the control unit may switch the valve (s) of the hoist system to the second valve position. The control unit may also adjust the speed of the vehicle power unit, to run at an appropriate operating speed for driving the pump, and this may cause the hydraulic

actuator (s) to retract and lower or move the body 17 towards the first body position.

When the lower function is being used, there is a risk that the body 17, especially if it is still partially loaded, may crash into the chassis 18, or the other vehicle member. To avoid this, the operator has hitherto had to manually engage a float function, by means of the body control device 24, before the body 17 reaches the end of its travel. In the vehicle 10 of the present disclosure, the control system may automatically engage the float function (a second mode of operation) under certain conditions. This may occur if the control system determines, from position signals generated by the position sensor (s), that the body 17 is at a predetermined position and that the lower

function is engaged. The control system may determine which function is in operation by determining the position of the body control device 24 from the hoist demand signal

generated by the body control device 24.

If the conditions are met, the control unit may switch the hoist valve (s) from the second (Retract) valve position to the third (Float) valve position to divert the flow of working fluid from the pump to the fluid tank or reduce it to zero. This may cause the actuator (s) to depressurise and allow the body 17 to move under its own weight. If the pump is electrically driven, the pump may be switched off. The predetermined position may be when the body 17 is at an angle of less than 5°, for example 2°, to the chassis 18. The float function may be automatically disengaged by the control unit if it determines that the body 17 is no longer in the predetermined position.

The automatically engaged float function may remain active until the operator next selects the raise function. This means that the body 17 may move (i.e., the hydraulic or other actuators may slightly extend/retract ) in response to any deflection of the chassis 18 under load whilst the vehicle 10 is travelling.

When the float function is engaged, the operator may at any time override this and select the hold function (if available) by moving the body actuator 24 to the appropriate position .

Alternatively, the float function may be automatically disengaged by the control unit when other vehicle system checks indicate that it is unsafe for the float function to remain active.

The vehicle 10 may also be provided with a "soft stop" function which is automatically activated when the body 17 is being raised and nears the body up position. Hitherto the operator has had to manually slow the speed of ascent and engage the hold function, by means of the body control device 24, when the body reaches the body up position. In the vehicle 10 of the present disclosure, the control system may automatically slow down the speed of movement of the body 17 as a second predetermined body position is reached and, when the body up position (a third predetermined body position) is reached, engage the hold function (a fourth mode of operation) . This may occur if the control system determines, from position signals generated by the position sensor (s), that the body 17 is at the second predetermined position and that the raise function is engaged. The control system may determine which function is in operation by determining the position of the body control device 24 from the hoist demand signal generated by the body control device 24.

If the conditions are met, the control unit may reduce the flow of working fluid to the actuator (s) when the second predetermined body position is reached, which slows down the speed of movement of the body 17. When the body 17 reaches the third predetermined body position, the control unit may switch the valve (s) of the hoist system from the first

(Extend) valve position to the fourth (Hold) valve position. This may cause the position of the body 17 to lock at this third predetermined position. The second predetermined body position may when the body 17 is at an angle of greater than 60° to the chassis 18 or other vehicle part. The third predetermined body position may when the body 17 is at an angle of 70° to the chassis 18 or other vehicle part. If the vehicle 10 has a Hold position for the body control device 24, when the operator wishes to engage the hold function, he may move the body control device 24 to the Hold position. This may provide a hold demand signal to the control unit. On receipt of this signal the control unit may switch the valve (s) of the hoist system to the fourth (Hold) position. The control unit may also adjust the speed of the vehicle's power unit to run at an appropriate operating speed for driving the pump. This may cause the position the body 17 to lock.