Patent Publication Number: US-2022227610-A1

Title: Load handling machine and method for controlling a load handling machine

Description:
The present invention relates to a load-handling machine, such as a machine with a telescopic or non-telescopic lifting arm, a power shovel, a bucket loading machine or the like, and to a method for controlling a load-handling machine. 
     It relates more particularly to a load-handling machine comprising:
         a wheeled chassis,   a drive system driving the movement of the wheeled chassis   a system for handling a load and borne by the chassis,   an operating unit,   a control device for controlling the load-handling system and able to be actuated manually by an operator, the operating unit being configured to receive control signals from said control device,   an activation member for the manually actuatable control device.       

     For safety reasons, the regulations dictate that measures be put in place to prevent accidental operation of the control device on load-handling machines. By way of example, accidental operation could be caused by the operator&#39;s clothing becoming caught on the control device so that the operator operates it unintentionally or without realizing. In order to address this problem, load-handling machines comprising an activation member activating the control device in order to avoid accidental operation using the control device have been developed, as illustrated in patents EP-0.981.078 and EP-1.523.704. However, the presence of such an activation member places restrictions on the operator. When the operator is no longer actuating the activation member, the operator has to actuate the control device almost continuously. As soon as the control device has not been actuated for a predefined period, the activation member has to be actuated again. In practice, the presence of this activation member notably obliges the operator to maintain near-constant hand contact with the activation member, which makes the machine less comfortable to operate and may lead to muscle fatigue. A device for controlling a handling machine and which takes account of the status, closed or open, of the door to the cab of the machine is also described, in patent EP 1 953 027. 
     It is an object of the invention to propose a load-handling machine of the aforementioned type the design of which makes it possible to avoid undesired actuation of the control device without detriment to how comfortable the machine is to operate. 
     To this end, one subject of the invention is a load-handling machine comprising:
         a wheeled chassis,   a drive system driving the movement of the wheeled chassis   a system for handling a load and borne by the chassis,   an operating unit,   a control device for controlling the load-handling system and able to be actuated manually by an operator, the operating unit being configured to receive control signals from said control device,   an activation member for the manually actuatable control device,   characterized in that the handling machine comprises a sensor sensing a parameter indicative of movement of the machine, and in that the operating unit is configured to allow the handling system to be operated using the control device as a function of at least the parameter indicative of movement of the machine. In this way it is possible to allow the handling system to be controlled using the control device as a function of at least the parameter indicative of movement of the machine when the activation member is in the actuated state or in the non-actuated state. This makes driving more comfortable but without detriment to safety.       

     According to one embodiment, the operating unit is configured so that, when the activation member for activating the control device is in the non-actuated state, said unit allows the handling system to be operated using the control device as a function of at least the parameter indicative of movement of the machine. 
     According to one embodiment, the operating unit is configured so that, when the activation member for activating the control device is in the non-actuated state, the activation member being in the non-actuated state as a result of said activation member having passed from the actuated state to the non-actuated state, said unit allows the handling system to be operated using the control device as a function of at least the parameter indicative of movement of the machine. 
     According to one embodiment, the sensor of a parameter indicative of movement of the machine is a sensor of a parameter indicative of the speed of travel of the machine, and the machine comprises a memory for storing a predetermined speed of travel of the machine, and the operating unit is configured so that, when the activation member for activating the control device is in the non-actuated state, said unit allows the handling system to be operated using the control device when the speed of travel of the machine as supplied by the sensor of a parameter indicative of the speed of travel of the machine is greater than the predetermined value stored in memory. 
     With the sensor of a parameter indicative of movement of the machine being a sensor of a parameter indicative of the speed of travel of the machine, the operating unit is therefore configured so that, when the activation member for activating the control device is in the non-actuated state, the activation member being in the non-actuated state as a result of said activation member having passed from the actuated state to the non-actuated state, said unit allows the the handling system to be operated using the control device as a function of at least the parameter indicative of the speed of travel of the machine. It is thus possible to allow the handling system to be controlled using the control device as a function of at least the speed of travel of the machine when the activation member is in the actuated state or in the non-actuated state. This makes driving more comfortable but without detriment to safety. 
     Thus, during phases of driving along, the operator is able not to have to concern themself with the activation member. 
     According to one embodiment, with the operating unit being configured so that, when the activation member is in the actuated state, said unit allows the handling system to be operated as a function at least of the control signals received from the control device, the operating unit is configured to:
         start at least one timer defining a time interval in the passage of the activation member from the actuated state to the non-actuated state,   to prevent the handling system from being operated using the control device when the time interval defined by the timer has elapsed, and   to reset the timer as a function at least of the data supplied by the sensor of a parameter indicative of movement of the machine during the time interval defined by the timer. It should be noted that, in the present application, what is meant by “reset” is the action of returning the timer, before the time interval defined by the timer has fully elapsed, to the initial state corresponding to the start of the timer.       

     The operating unit is therefore configured to reset the timer, before the time interval defined by the timer has fully elapsed, as a function of at least the data supplied by the movement sensor. Thus, the resetting or lack of resetting of the timer is dependent on at least on the movement of the machine. 
     The feature whereby the operating unit is able to reset the timer, namely to make the time interval defined by the timer start elapsing again from the beginning, as a function of the data supplied by a sensor of the speed of travel, namely the running speed, of the load-handling machine, means that the operator need not concern themself with actuating the activation member and the control device, at least during certain phases of running, this being without detriment to safety. This makes driving more comfortable for the operator. The operator may thus, during these phases of running, position their hand as they might wish, without being constrained, as they were in the prior art, to keeping their hand in a position of actuation of the activation member, or to almost continuously actuating the control device. 
     According to one embodiment of the invention, with the sensor of a parameter indicative of movement of the machine being a sensor of a parameter indicative of the speed of travel of the machine, the operating unit is configured to reset the timer when the speed of travel of the machine as supplied by the sensor of a parameter indicative of the speed of travel of the machine is greater than the predetermined speed stored in memory. The operating unit is therefore configured to reset the timer, before the time interval defined by the timer has fully elapsed, when the speed of travel of the machine is greater than the predetermined speed stored in memory. Thus, when the speed of travel of the machine is greater than a predetermined value, the operator need not concern themself with the activation member for activating the control device and is not obliged, as they were in the prior art, to actuate the activation member that activates the control device almost continuously in order to be able to operate the handling system using the control device. 
     According to one embodiment of the invention, the operating unit is configured to reset the timer as a function at least of the control signals received from the control device. The operating unit is therefore configured to reset the timer, before the time interval defined by the timer has fully elapsed, as a function of at least the control signals received from the control device. Thus, when the activation member is in the non-actuated state, operation of the handling system using, which is to say with the aid of or through the agency of, the control device remains possible as long as the control device is actuated within the time interval defined by the timer. 
     According to one embodiment of the invention, the control device that controls the handling system is a control device comprising at least two control elements. 
     According to one embodiment of the invention, the control device for controlling the handling system is a multifunction control device and at least one of the control elements is configured to control at least part of the handling system, and the other control element or another of the control elements is configured to control at least part of the drive system driving the movement of the machine. 
     According to one embodiment of the invention, one of the control elements of the control device for controlling the handling system is a lever, and the other control elements are borne by said lever. 
     According to one embodiment of the invention, the activation member is borne by the control device for controlling the handling system. Thus, in practice, the positioning of the operator&#39;s hand on the control device may allow both actuation of the control device and actuation of the activation member that activates the control device. 
     According to one embodiment of the invention, the control device comprises a manual part configured to be grasped in the hand, and the activation member is a presence sensor arranged on the manual part of the control device. The presence sensor arranged in said manual part therefore forms a sensor that detects the presence of an operator&#39;s hand on said control device in the state in which the control device has been grasped by hand in accordance with its purpose. 
     According to one embodiment of the invention, the handling system comprises at least one handling arm mounted on said chassis rotatable about a horizontal axis of rotation and at least one actuator driving said handling arm in its movement about said horizontal axis of rotation. 
     According to one embodiment of the invention, the machine comprises a driver station, the driver station is equipped with a detection system enabling detection of the presence or absence of the operator at said station, this detection system comprising at least one presence detector configured to detect the presence of an operator at least at one location of said driver station, and the operating unit is configured so that, when the activation member is in the non-actuated state after the activation member has passed from the actuated state to the non-actuated state, said unit prevents or allows at least the handling system to be operated using the control device at least as a function of the status, operator-absent or operator-present, detected by the detection system for detecting the presence of the operator at said station. 
     According to one embodiment of the invention, the driver station takes the form of an operator cab inside which there is at least one seat on which the operator can sit, said operator cab being closed by a door, and the seat is equipped with the or at least one of the presence-detection sensors of the detection system for detecting the presence of the operator at said station. 
     According to one embodiment of the invention, the system for detecting the presence of the operator at said station comprises at least one sensor for detecting the opening and/or the closing of the door. 
     According to one embodiment of the invention, the operating unit is configured to start at least one additional timer referred to as the presence timer defining a time interval when the activation member passes from the actuated state to the non-actuated state, and to prevent the handling system from being operated using the control device when the time interval defined by the presence timer has elapsed, and the operating unit is configured to reset the presence timer as a function of at least the status, operator-absent or operator-present, detected by the detection system for detecting the presence of the operator at said station. The operating unit is therefore configured to reset the presence timer, before the time interval defined by the timer has fully elapsed, as a function of at least the status, operator-absent or operator-present, detected by the detection system for detecting the presence of the operator at said station. This results in the possibility to quickly detect the absence of an operator and prevent any resetting of the timer when the absence of an operator is detected. 
     A further subject of the invention is a method for controlling a load-handling machine comprising:
         a wheeled chassis,   a drive system driving the movement of the wheeled chassis,   a system for handling a load and borne by the chassis,   an operating unit,   a control device for controlling the load-handling system and able to be actuated manually by the operator, the operating unit being configured to receive control signals from said control device,   an activation member for the manually actuatable control device, said method comprising a step of manually actuating the activation member that activates the control device so that when the activation member is in the actuated state, the handling system is allowed to be operated as a function at least of the control signals received from the control device, characterized in that, with the handling machine comprising a sensor of a parameter indicative of movement of the machine, said method comprises a step of authorizing the operation of the handling system using the control device as a function of at least the parameter indicative of movement of the machine.       

     According to one embodiment of the method, with the sensor of a parameter indicative of movement of the machine being a sensor of a parameter indicative of the speed of travel of the machine, and with the machine comprising a memory for storing a predetermined speed of travel of the machine, when the activation member is in the non-actuated state, the non-actuated state being a result of the activation member having passed from the actuated state to the non-actuated state, the handling system is allowed to be operated using the control device when the speed of travel of the machine is greater than the predetermined value stored in memory. 
     According to one embodiment of the method, the method comprises:
         a step of starting a timer defining a time interval in the passage of the activation member from the actuated state to the non-actuated state   a step of preventing the handling system from being operated using the control device when the time interval defined by the timer has elapsed,   a step of resetting the timer as a function of the data supplied by the sensor of a parameter indicative of movement of the machine during the time interval defined by the timer.       

     The method therefore comprises, before the time interval defined by the timer has fully elapsed, a step of resetting the timer as a function of the data supplied by the sensor of a parameter indicative of movement of the machine, such as a sensor of a parameter indicative of the speed of travel of the machine 
     According to one embodiment of the method, the method comprises a step of resetting the timer as a function of the control signals from the control device. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be clearly understood upon reading the following description of exemplary embodiments, with reference to the appended drawings, in which: 
         FIG. 1  depicts a schematic view of a load-handling machine according to the invention, with the lifting arm in the raised position; 
         FIG. 2  depicts a perspective view of a load-handling machine according to the invention, with the lifting arm in the lowered position; 
         FIG. 3  depicts a partial view of a control device viewed from the activation-member side; 
         FIG. 4  depicts a partial view of a control device viewed from the opposite side to the activation-member side; 
         FIG. 5  is a schematic depiction of components of the machine; 
         FIG. 6  is a schematic depiction of a control method that can be implemented by the handling machine of  FIG. 1 ; 
         FIG. 7  is a schematic depiction of a control method that can be implemented by the handling device of  FIG. 1 . 
     
    
    
     The concept of the invention is described in more detail below with reference to the appended drawings, which show embodiments of the concept of the invention. Reference throughout the specification to “an/one embodiment” means that a particular functionality, structure or feature described in connection with an embodiment is included in at least one embodiment of the present invention. Thus, the occurrence of the expression “in one embodiment” in various places throughout the specification does not necessarily refer to the one same embodiment. Furthermore, the particular functionalities, structures or features may be combined in any suitable manner in one or more embodiments. 
     As mentioned hereinabove, the invention relates to a load-handling machine  1  according to that depicted in  FIG. 1 . This machine  1  comprises a chassis  2  fitted with wheels  20  to rest on the ground and form a wheeled chassis  2 . This wheeled chassis  2  is surmounted by a driver station  15 . The driver station  15  takes the form of an operator cab  151  inside which there is at least one seat  18  on which the operator can sit. The operator cab  151  is closed by a door  19 . The machine  1  also comprises a drive system  3  driving the movement of the wheeled chassis  2  by driving a rotational movement of the wheels  20  of the machine  1 . This drive system  3  the driving the chassis  2  comprises, in a way known per se, a combustion engine connected to the wheels  20  by a transmission. This drive system  3  driving the movement of the chassis  2  is controlled notably using a throttle pedal, not depicted, positioned in the operator cab  151 . 
     The handling machine  1  further comprises a system  4  for handling a load and borne by the chassis  2 . This handling system  4  comprises at least one handling arm  13  mounted on said chassis  2  rotatable about a horizontal axis  21  of rotation and at least one actuator  14  driving said handling arm  13  in its movement about the horizontal axis  21  of rotation. The handling arm  13  is therefore a pivoting arm mounted with the ability to pivot about the horizontal axis  21 , orthogonal to the longitudinal axis of the arm, so that the arm  13  can be moved from a lowered position to a raised position and vice versa using the actuator  14 , such as a hydraulic ram connected to a hydraulic pump by a hydraulic circuit, the pump and the circuit not being depicted. The arm may be a telescopic arm the length of which can be adjusted between a retracted position and a deployed position of the arm. To this end, the arm  13  may be formed of two arm sections of which one, referred to as the first section, is coupled, with the ability to pivot, to the chassis  10  and of which the other, referred to as the second section, is nested in the first arm section with the ability to slide therein. As an alternative, it is possible for the arm not to be telescopic. 
     The nested sliding relative movement of the arm sections can be obtained using a second actuator of the machine, such as a double-acting ram, housed in the first arm section and fixed by its rod to the second arm section to allow the arm sections to be driven in relative motion with respect to one another under the effect of the retraction or deployment of the ram rod. 
     The load-handling arm  13  may be equipped, at its free end, with an accessory  23  connected to the arm by a pivoting connection. This accessory  23  may be driven about the pivot of the pivoting connection by an actuator  25  which may once again be formed by a double-acting hydraulic ram or by two single-acting rams in parallel and operated in turn. 
     In the example depicted, this accessory  23  comprises a forks holder and the actuator  25  allows the forks holder to be made to move between a pick-up position and a discharge position through the pivoting of the accessory about an axis referred to as horizontal, orthogonal to the longitudinal axis of the arm  13 . This pivot axis is parallel to the pivot axis  21  about which the arm  13  is connected to the chassis  10 . The discharge position corresponds to the most groundwardly-pivoted position of the forks holder. The pick-up position of the forks holder corresponds to an upwardly pivoted position of the forks holder and of the associated load  24  when such a load is present. 
     The handling machine  1  further comprises an operating unit  5  configured to control the operation of the actuators  14  and  25  and, where appropriate, the deployment of the telescope when there is one, making it possible to bring about the movement of the arm  13  and of the accessory  23 . 
     The operating unit  5  is an electronic and/or computerized unit which, for example, comprises a microcontroller or a microprocessor associated with a memory. Thus, when it is stated that the unit or means belonging to said unit are configured so as to perform a given operation, this means that the unit comprises computer instructions and the corresponding execution means that make it possible to perform said operation and/or corresponding electronic components. 
     In other words, the functions and steps described may be implemented in the form of a computer program or via hardware components (for example programmable gate arrays). In particular, the functions and steps carried out by the operating unit  5  may be performed by sets of instructions or computer modules implemented in a processor or controller or be performed by dedicated electronic components or FPGA or ASIC components. It is also possible to combine computer parts and electronic parts. 
     The operating unit  5  therefore controls the handling system  4  and, in particular, the movements of the arm  13  and of the accessory  23  by controlling the corresponding actuators  14  and  25  via the hydraulic circuit. 
     The control signals supplied by the operating unit  5  generally act on members, such as distributors or valves, placed on the connection between the pump and the actuators  14 ,  25  so as to allow appropriate supply of fluid to the actuators  14 ,  25 , in a way known per se. 
     The handling machine  1  further comprises a control device  6  for controlling the load-handling system  4 . This control device  6  is manually actuated and is able to supply control signals to the operating unit  5 . These control signals are processed by the operating unit  5 . From these control signals, the operating unit  5  generates control signals for controlling at least the load-handling system  4  as described hereinabove. 
     In the examples depicted, the control device  6  for controlling the load-handling system  4  is a multifunction control device  6 . Specifically, the control device  6  can be used for controlling, on the one hand, the handling system  4  and, on the other hand, the system  3  that drives the movement of the machine  1 . In a variant, the control device  6  could have been a control device allowing control only of the handling system  4 . In what follows, it will always be considered that the control device  6  is a multifunction control device. Thus, this control device  6  for controlling the handling system  4  comprises at least two control elements. In the examples depicted, one of the control elements, depicted as  10  in the figures, is configured to control at least part  4  of the handling system, and another control element, depicted as  11  in the figures, is configured to control at least part of the system  3  driving the movement of the machine  1 . Other control elements, depicted as  12   a  and  12   b  in the figures, are also present. This control device  6  may adopt a wide variety of forms. 
     In the example depicted in  FIGS. 1, 3 and 4 , the control element  10  of the control device  6  for controlling the handling system  4  is a lever or joystick that the operator of the machine can manipulate by hand, and the other control elements  11 ,  12   a ,  12   b  are borne by said lever. These other control elements are located on the pommel of the lever. This lever pommel corresponds to that manual part  61  of the control device  6  which is configured to be grasped when the control device is being grasped in the hand in accordance with its purpose. 
     Such a control device is well known to those skilled in the art and an example of such a control device is described for example in patent FR-2.858.861. 
     The control lever or joystick transmits position signals from said lever to the operating unit  5  in a way known per se. These position signals may be interpreted by the operating unit  5  as signals instructing the movement of the arm  13  and/or the accessory  23 . 
     According to one embodiment, the control lever may thus be moved forward toward the front, backward toward the rear, or toward the left or toward the right of the machine. In the example depicted, this control lever able to move at least in the forward/backward direction toward the front/rear of the machine is mounted with the ability to move forward, to control the lowering of the arm  13 , and backward, to control the raising of the arm  13 . The forward/backward movement of the control lever may thus control the operation of the first actuator  14  between arm  13  and chassis  2 . This control lever  10  may further be mounted with the ability to move in the left/right direction, transverse to the forward/backward direction, to the left in order to command the pick-up position, and to the right to command the discharge position of the accessory  23 . The left/right movement of the control lever thus controls the operation of the first actuator  25  between accessory  23  and arm  13 . These forward/backward and left/right directions correspond to the main directions and the control lever may be driven in an infinite number of directions, the moving of the control lever in a given direction corresponding to a combined action proportionate to the position of the control lever with respect to the main directions. As illustrated in  FIG. 4 , the control lever may be equipped with a control element  12   a  such as a knob for controlling the telescoping actuator in order to telescope out in the case of a telescopic arm  13 . Thus, the rotating of the knob borne by the control lever in one direction allows the arm  13  to be deployed through a sliding movement in the direction of an extension of the arm  13  of the second arm section, and the rotating of the knob borne by the lever in an opposite direction allows the arm to be retracted. 
     Other buttons, knobs or the like, such as the one depicted as  12   b  in  FIG. 3 , may be provided for controlling certain functions of the accessory. One of the control elements, which has been depicted as  11  in the figures, is configured to control at least part of the system  3  that drives the movement of the machine. This control element  11  may be formed of a reversing button with three stable positions, in order to cause the machine to operate in forward running, to stop in a neutral position, or to operate in reverse running. The transmission of the system  3  for driving the movement of the chassis  2  may comprise a gearbox and the gearbox upshift and downshift control may be performed using a push-button or some other control member borne by the lever. It will be appreciated that these control elements may therefore, nonlimitingly, be realized in the form of a knob, a switch, a button, a changeover switch, a sensor, notably a Hall-effect sensor, a potentiometer, or the like. 
     The lever and the control elements borne by the lever can be actuated by the operator with just one hand when that hand of the operator is positioned on the manual part  61  of the control device  6  here formed by at least part of the pommel of the control lever. 
     The handling machine  1  further comprises an actuating member  7  for actuating the manually actuatable control device  6 . This activation member  7  is borne by the control device  6  for controlling the handling system  4 . 
     The activation member  7  is a presence sensor able to detect the presence of an operator&#39;s hand on said control device  6  in the state in which the control device  6  has been grasped by hand in accordance with its purpose. In particular, the activation member  7  is a presence sensor arranged on the manual part  61  of the control device  6 . This activation member  7 , which is manually actuated, is therefore configured to pass from the non-actuated state to the actuated state when a hand is present on the manual part  61  of the control device  6  and, conversely, from the actuated state to the non-actuated state in the absence of a hand on the manual part  61  of the control device  6 . It should be noted that the term “actuated” should be understood in its broadest sense. Actuating the activation member  7  means acting upon the activation member  7 . Actuation of the activation member  7  may therefore, nonlimitingly, occur through simple contact, by resting or by pressure, through the presence of a hand at a distance closer than a predetermined distance, or the like, without departing from the scope of the invention. 
     The activation member  7  may, by way of example, be produced in the form of a button of the push-button type or of a sensor of the capacitive type. The presence of a hand facing the activation member  7 , including contactless presence, may be enough to actuate the activation member  7  in the case of a capacitive-type sensor. 
     The role of this activation member  7  that activates the control device  6  will be described hereinafter. 
     The handling machine  1  further comprises a sensor  8  of a parameter indicative of movement of the machine. The operating unit  5  is configured to receive the data supplied by this sensor  8 . The operating unit is configured to allow the handling system to be operated using the control device as a function of at least the data supplied by this sensor  8 . This sensor  8  may adopt a wide variety of forms. Preferably, this sensor  8  of a parameter indicative of movement of the machine  1  is a sensor of a parameter indicative of the speed of travel of the machine  1  and the operating unit, configured to allow the handling system to be operated using the control device as a function of at least a parameter indicative of movement of the machine, is configured to allow the handling system to be operated using the control device as a function of at least a parameter indicative of the speed of travel of the machine. This speed sensor  8  may be a sensor that measures the rotational speed of the wheels or of any other mechanical member indicative of the speed of travel of the machine. A non-zero speed may also be detected by detecting the driving of a transmission component engaged with the wheels. 
     Finally, the machine  1  may comprise, at the driver station  15 , a system  16  for detecting the presence of the operator at the driver station. This detection system  16 , which is able to detect the absence or presence of the operator at said station, comprises at least one presence sensor  17 . This presence sensor  17  is distinct from the manual part  61  of the control device  6 . The operating unit  5  is configured so that, when the activation member  7  is in the non-actuated state after the activation member  7  has passed from the actuated state to the non-actuated state, said unit prevents or allows at least the handling system  4  to be operated using the control device  6  at least as a function of the status, operator-absent or operator-present, detected by the detection system  16  for detecting the presence of the operator at said station  15 . 
     In the examples depicted, the presence sensor  17  of the detection system  16  is a sensor with which the operator seat  18  is equipped and which is sensitive to the pressure of the applied weight. This sensor is in the active state and emits a signal when the operator is seated on the seat. The detection system  16  may further comprise a sensor  22  that detects the opening/closing of the door  19  of the cab  151 . This sensor is in the active state and emits a signal when the door is in the closed state. The detection system  16  further comprises a processing module  161  allowing the processing of the signals from said sensors  17  and  22  in order to detect the presence or absence of the operator. This processing module  161  may be incorporated into the operating unit  5 . The operating unit  5  is configured so that, when the activation member  7  is in the non-actuated state after the activation member  7  has passed from the actuated state to the non-actuated state, said unit prevents the handling system  4  from being operated using the control device  6  when the absence of the operator is detected. It should be noted that the presence of an operator is detected by the detection system  16  when the presence sensor  17  situated in the seat  18  is active or when, with the door having been detected as being in the closed state by the sensor  22  that detects the opening/closing of the door  19 , the presence sensor  17  situated in the seat is in the inactive state and has passed from the active state to the inactive state with the door in the closed state without an opening of the door being detected. The signals from these sensors are sent to the processing module  161 . 
     As explained hereinafter, the operating unit  5  is configured to allow or prevent the operation of the machine, particularly of the handling system  4  and of the system  3  for driving the movement of the wheeled chassis, from the control device  6 . 
     The operating unit  5  is configured to receive signals from the activation member  7  when the activation member  7  is in the actuated state. Thus, in instances in which the activation member  7  is a push-button, a signal of actuation of the activation member  7  is supplied to the operating unit  5  when the operator&#39;s hand, placed on the control system  6 , depresses the push-button. 
     In the case of an activation member  7  formed by a capacitive sensor, a signal is supplied to the operating unit  5  simply by the operator&#39;s hand being positioned on the control device  6  facing said sensor. 
     When the activation member  7  is in the actuated state, control of the handling system  4  and of at least part of the drive system  3  driving movement is allowed as a function of at least the control signals received from the control device  6 , these control signals being the result of actuation by the operator of the control device  6  as described hereinabove. 
     When the activation member  7  is in the non-actuated state, this non-actuated state of the activation member  7  being the result of said member  7  passing from the actuated state to the non-actuated state, control of the handling system  4  and of at least part of the drive system  3  using the control device  6  is allowed as a function of at least the speed at which the machine  1  is advancing. 
     To this end, the machine  1  comprises a memory  9  for the storage of a predetermined speed of travel of the machine  1 , and the operating unit  5  is configured so that, when the activation member  7  activating the control device  6  is in the non-actuated state, the unit allows the handling system  4  to be controlled using the control device  6  when the speed of travel of the machine is greater than the predetermined value stored in memory. 
     The machine  1  comprises at least one timer T 1  defining a time interval which may be predefined or adjustable. This timer T 1  is, in the conventional way, embodied by a clock, and the time is counted incrementally or decrementally until the time interval defined by the timer T 1  has elapsed. Said clock is preferably incorporated into the operating unit  5 . This timer T 1  starts when the activation member  7  passes from the actuated state to the non-actuated state, namely when the push-button is released or a hand is removed from a position facing the capacitive sensor. The operating unit  5  is configured to prevent the handling system  4  and possibly part of the system  3  driving the movement of the chassis  2  from being operated using the control device  6 , namely from or by means of the control device  6 , when the time interval defined by the timer T 1  has elapsed. 
     In order to prevent such a disabling when the machine  1  is in a driving-along phase, the operating unit  5  is configured so that, while the time interval defined by the timer is elapsing, the timer T 1  can be reset, namely can restart its count or, respectively, its countdown of the time interval defined by the timer T 1 , as a function of at least the data supplied by the sensor  8  that senses the speed of travel of the machine  1 . 
     In particular, with a predetermined speed of travel of the machine  1  having been stored in the memory  9 , the operating unit  5  is configured to reset the timer T 1  when the speed of travel of the machine  1 , as supplied by the sensor  8  that senses the speed of travel of the machine, is greater than said predetermined speed stored in memory. 
     Thus, by way of example, the operating unit  5  is configured to reset the timer T 1  when the speed of the machine is greater than 1 km/h. 
     In the same way, to prevent such a disabling of control, when the control device  6  is actuated by the operator, the operating unit  5  is also configured to reset the timer T 1  as a function of at least the control signals received from the control device  6 . 
     Thus, after the activation member  7  has passed from the actuated state to the non-actuated state, as long as the control device  6  is actuated, namely as long as the lever or any one of the control elements of the lever are actuated within the time interval defined by the timer T 1 , control from the control device  6  remains possible. This control, from the control device  6 , ceases as soon as the control device  6  has remained non-actuated for a duration longer than the time interval predefined by the timer T 1  while at the same time the speed of travel of the machine is below a predetermined speed. A further actuation of the activation member  7  is needed in order to restore the possibility of this control from the control device  6 . 
     In order to enhance the machine and prevent control notably of the handling system  4  from the control device  6  in a way that is even more responsive, when a seemingly abnormal situation arises, the operating unit  5  is configured to start at least one additional timer referred to as the presence timer T 2  defining a time interval when the activation member  7  passes from the actuated state to the non-actuated state, and to prevent the handling system  4  from being operated using the control device  6  when the time interval defined by the presence timer T 2  has elapsed. The operating unit  5  is configured to reset the presence timer T 2  as a function of at least the signals supplied by the detection system  16  for detecting the presence of the operator at said station  15 . 
     In practice, the operating unit  5  is configured to prevent the presence timer T 2  from being reset as long as the absence of the operator from the driver station  15  is detected. This absence of the operator may correspond:
         either to an absence of a signal from the presence-detection sensor  17  with which the seat  18  of the driver station  15  is equipped when the door  19  to the operator cab  151  is in the open state   or, when the door  19  is in the closed state, to an absence of signal from the presence-detection sensor  17  with which the seat  18  of the driver station  15  is equipped, the absence of a signal from the present-detection sensor  17  having begun when the door was in the open state. The presence timer T 2  defines a time interval of duration shorter than the time interval of the timer T 1  so as to disable as quickly as possible control from the control device  6  when the absence of the operator is detected. In the event that the presence of the operator is detected, this presence timer T 2  is reset if the control device  6  is actuated within the time interval defined by the presence timer T 2  or if the speed of travel of the machine is greater than a predetermined speed. Otherwise, this presence timer T 2  is not reset.       

     Example of control method: 
     The control unit may be configured to implement a method for controlling the machine, as depicted in  FIGS. 6 and 7 . As explained hereinafter, the control method serves to allow or prevent the control of the handling system  4  and of at least part of the system  3  driving the movement of the machine from the control device  6  notably on the basis of the speed of the machine. According to one particular aspect, the method is executed in real time. In what follows, it is considered that the control device  6  is able to generate signals for controlling both the handling system  4  and at least part of the drive system  3  that drives the movement of the machine. As a variant, the control device  6  could have been capable only of generating signals for controlling the handling system  4 , without departing from the scope of the invention. 
     In step S 1 , the activation member  7  is not actuated and control of the handling system  4  and of at least part of the movement-drive system  3  from the control device  6  is prevented. 
     In step S 2 , the activation member  7  is actuated by depressing the push-button or by positioning a hand facing the capacitive sensor. It therefore supplies an actuation signal to the operating unit  5 . 
     In step S 3 , the operating unit on the basis of this actuation signal allows control of the handling system  4  and of at least part of the drive system  3  on the basis of the control signals supplied by the control device  6 . 
     In step S 4 , the control method tests whether the activation member  7  is in the non-actuated state, namely whether a signal of non-actuation of the activation member  7  is being supplied by the activation member  7 . The control method loops back on this step S 4  until the activation member  7  becomes non-actuated. 
     The control method then moves on to step S 5 , where a timer T 1  defining a time interval of, for example, 10 seconds begins. The 10-second deadline begins its count and the control method moves on to step S 6 . In step S 6 , the speed of the machine is compared against a threshold speed value stored in memory and generally equal to 1 km/h. If the speed is greater than the threshold speed, then the control method returns to step S 5  to start the timer T 1  again, which corresponds to a resetting of the timer T 1 . The 10-second deadline therefore begins its count again. If the speed is below the threshold speed, then the control method moves on to step S 7 , which tests for actuation of the control device  6 . 
     The operating unit  5  has a module for processing the control signals supplied by the control device  6 . In the simplest version, mere receipt by the operating unit  5  of control signals supplied by the control device  6  irrespective of the type of signal may be considered by the operating unit  5  to represent actuation of the control device  6 . If the control device  6  is actuated, then the control method returns to step S 5 , where the timer T 1  is again reset. If the control device  6  is not actuated, then the control method moves on to step S 8 , where the time elapsed within the time interval defined by the timer T 1  since the timer T 1  was set is compared against the total duration of the time interval of that timer. When this time elapsed is greater than the duration of the time interval defined by the timer, the timer T 1  is considered to have timed out and the control method then returns to step S 1 . Otherwise, the control method returns to step S 5  to reset the timer T 1  again and potentially re-execute steps S 6  and S 7 . 
     Thus, in summary, in the state in which the activation member  7  is not actuated and the timer T 1  has started, if the speed of travel of the machine is less than 1 km/h and if the control device  6  is not actuated within the time interval defined by the control timer T 1 , then, when the time interval T 1  comes to an end, control using the control device  6  is prevented and further actuation of the activation member  6  is required in order to be able to control the machine from the control device  6 . 
     In step S 4 , the control method moves on, in parallel, to step S 5  and to step S 10 , where a timer T 2 , referred to as presence timer, is started. 
     In step S 11 , the detection system  16 , as a function of the signals supplied by the sensor  17  for sensing the presence of the operator at the station  15 , and in particular on the seat  18  of the driver station  15 , and possibly of the signals supplied by the sensor  22  that detects the opening/closing of the door  19  and of the processing of said signals, detects the presence or absence of an operator at the driver station  15 . 
     When the detection system  16  comprises a presence sensor  17 , the absence of the operator at the driving station is detected, for example, if no signal is supplied by the presence sensor  17 . When the detection system  16  comprises a presence sensor  17 , and a sensor  22  detecting the opening/closing of the door  19 , the absence of the operator at the driving station is detected, for example, if no signal is supplied by the presence sensor  17  and if the door is detected as being open. The control method moves on to a step S 13  which checks whether the time interval defined by the timer T 2  has elapsed. The control method tests by looping back through steps S 11  and S 13  as long as the time interval of the timer T 2  has not elapsed. If the time interval defined by the timer T 2  has elapsed, then the control method returns to step S 1 . 
     If, conversely, in step S 11 , the detection system  16  detects, as a function of the signals supplied by the sensor  17  for sensing the presence of the operator at the driver station  15 , and by the sensor  22  that detects the opening/closing of the door and of the processing of said signals, the presence of the operator at the driver station, for example if a presence signal is supplied by the presence sensor  17 , then the control method moves on to step S 12 , where it performs a test similar to steps S 6  and S 7 , namely tests whether the speed of travel is greater than 1 km/h and whether the control device  6  is being actuated. 
     If the result of these tests is in the affirmative, then the control method returns to step S 10 , where the timer T 2  is reset. Otherwise, the control method moves on to step S 13 . 
     In step S 13 , if the time interval defined by the timer T 2  has not elapsed, then the control method returns to step S 11 . 
     In summary, in this control method of  FIG. 7 , in the state in which the activation member  7  is not actuated and the timer T 2  has started, when the absence of the operator is detected using the detection system  16  and the time elapsed since the timer T 2  started is greater than the time interval defined by said timer T 2 , control using the control device  6  is prevented and further actuation of the activation members  7  is required in order to be able to control the machine from the control device  6 . 
     It should be noted that the time interval defined by the timer T 2  is shorter than the time interval defined by the timer T 1 . 
     Although the invention has been described in connection with a number of particular embodiments, it is quite obvious that it is not in any way restricted thereto and that it encompasses all technical equivalents of the means described and combinations thereof where these fall within the scope of the invention. 
     The use of the verb “have”, “comprise”, and “include” does not exclude the presence of elements or steps other than those listed in a claim.