Abstract:
An earth-moving vehicle includes a mobile operating arm; at least one actuator for moving the operating arm through a plurality of positions, wherein one of the plurality of positions is a pre-defined reference position; a control for actuating the actuator; and a configuration device. The configuration device includes a sensor designed for detecting at least the pre-defined reference position of the operating arm and for issuing a corresponding position signal, a disabling valve activated automatically according to the position signal to disable actuation of the actuator when the operating arm reaches the predetermined reference position, and a re-enabling switch which can be switched manually by an operator for deactivating the disabling means to enable the actuator to be actuated.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to an earth-moving vehicle provided with a chassis, with an operating arm that is mobile with respect to the chassis, and with a device for configuring the profile of the vehicle by setting the operating arm in a pre-determined reference position such as to enable circulation of the vehicle on the road. 
   2. Description of the Background of the Invention 
   As is known, the operating arm of earth-moving vehicles is of an articulated type, is actuated by a plurality of hydraulic cylinders, and must be configured in a pre-determined reference position when the vehicle circulates on the road, so as to respect the parameters of maximum encumbrance laid down in the highway code (for example, in Germany, the maximum height from the ground of the vehicle must be less than 4 meters (13 feet), whilst in the longitudinal direction of advance of the vehicle the distance of the operating arm from the steering column must be less than 3.5 meters (11.5 feet)). 
   In order to position the operating arm in such a way as to satisfy these parameters, the driver must actuate the manual controls present in the cab for bringing the rods of the cylinders into a pre-set end-of-travel position, except for one of these cylinders, the rod of which must be set in a pre-defined intermediate position. This cylinder is normally the one that moves the last stretch of the operating arm, i.e., the one that carries the earth-moving member at its end. 
   In order to position the rod of this cylinder in the pre-defined intermediate position, the driver must visually control the relative displacement of the various portions of the operating arm, but this operating modality is, on the one hand, somewhat inconvenient for the driver who has to maneuver the controls within the cab of the vehicle and, on the other, relatively imprecise, precisely because it depends totally upon the sensitivity of the driver himself. 
   There is thus felt the need to provide an earth-moving vehicle equipped with a device for configuration of the profile for circulation on the road, which will enable a precise positioning to be obtained irrespective of the sensitivity of the driver and of possible subsequent accidental maneuvers made by the driver himself on the controls present in the cab. 
   The purpose of the present invention is to provide an earth-moving vehicle equipped with a device for configuration of the profile for circulation on the road, which will enable the need outlined above to be met in a simple and economically advantageous way. 
   SUMMARY OF THE INVENTION 
   According to an aspect of the present invention, an earth-moving vehicle includes a mobile operating arm; at least one actuator for moving the operating arm through a plurality of positions, wherein one of the plurality of positions is a pre-defined reference position; a control for actuating the actuator; and a configuration device. The configuration device includes a sensor designed for detecting at least the pre-defined reference position of the operating arm and for issuing a corresponding position signal, a disabling valve activated automatically according to the position signal to disable actuation of the actuator when the operating arm reaches the predetermined reference position, and a re-enabling switch which can be switched manually by an operator for deactivating the disabling means to enable the actuator to be actuated. 
   The invention will now be described with reference to the annexed drawings, which illustrate a non-limiting example of an embodiment thereof. 

   
     BRIEF DESCRIPTION OF THE FIGURES 
       FIG. 1  illustrates, in side elevation, a preferred embodiment of the earth-moving vehicle provided with a device for configuration of the profile for circulation on the road, according to the present invention; and 
       FIGS. 2 and 3  are two partial diagrams, one electrical and the other hydraulic, of the vehicle of  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   In  FIG. 1 , the reference number  1  designates an earth-moving vehicle, in particular an excavating vehicle, comprising a chassis  2  and an operating arm  3 , which is made up of a stretch  4   a  hinged to the chassis  2 , a terminal stretch  5 , which carries at its end an operating member  6  for earth moving, and an intermediate stretch  4   b , hinged to the stretches  4   a  and  5 . 
   The member  6  and the stretches  4   a ,  4   b  and  5  are rotated with respect to one another and with respect to the chassis  2  by means of a plurality of hydraulic cylinders, designated by the reference numbers  7   a ,  7   b ,  8 ,  9 , which form part of a hydraulic circuit  10  of a known type. The circuit  10  is illustrated schematically in  FIG. 3  and only as regards the part corresponding to the actuation of the cylinder  8 , i.e., the part designed for rotating the stretch  5  with respect to the stretch  4   b , the other cylinders being actuated in a basically similar manner. 
   With reference to  FIG. 3 , the circuit  10  comprises a pilot valve  11  and a main valve  12  for continuous positioning, which is controlled by the valve  11  itself for control of the flow of oil from and to the cylinder  8 . The pilot valve  11  is in turn controlled by the driver of the vehicle, in a known way (not described herein in detail), by means of manual-control members  16  set in the cab of the vehicle  1 , to cause the rod  14  to be retracted or to come out with respect to the liner  15  of the cylinder  8 . 
   The oil that performs the function of driving the valve  12  is supplied to the valve  11  by a pump  17  and through a pipe  18 , along which there is set a bistable control solenoid valve  19 . The solenoid valve  19  is controlled by a corresponding solenoid C for selectively switching between a disabling position, in which supply of oil to the valve  11  is blocked so as to inhibit driving of the valve  12  and hence actuation of the cylinder  8  by the driver, and an enabling position, in which it allows oil to flow to the valve  11  so as to enable driving of the valve  12  and hence actuation of the cylinder  8 . According to an alternative variation, the solenoid valve  19  is set on a pipe in which there flows oil that supplies all the pilot valves of the circuit  10 , and not only the valve  11 , so as to inhibit/enable actuation of all the cylinders associated with displacement of the arm  3  and of the member  6 , and not only actuation of the cylinder  8 . 
   The solenoid valve  19  forms part of a device  20  for automatic configuration of the profile, which enables setting of the stretches  4   b  and  5  in a predetermined relative reference position such as to satisfy parameters of maximum encumbrance of the vehicle  1  laid down in the highway code and hence to enable circulation of the vehicle  1  on the road. 
   With reference to  FIG. 2 , the device  20  comprises a position sensor  22  (illustrated schematically), preferably a proximity sensor, which is associated with the arm  3  for detecting when the aforesaid predetermined relative reference position is reached between the stretches  4   b  and  5 , and accordingly issue a corresponding position signal or enable signal. 
   The device  20  further comprises an electrical circuit  23  (schematically illustrated), which in turn comprises a supply line  25  and a relay  26  set between the line  25  and the solenoid C. The relay  26  may be switched between a first operating position, in which the line  25  supplies electric current to the solenoid C for energizing the solenoid C itself and maintaining the solenoid valve  19  in its enabling position, and a second operating position, in which the line  25  supplies electric current to an acoustic signaling device  27 , or buzzer, preferably of a timed type, whilst the solenoid C is not energized to switch the solenoid valve  19  to its disabling position. 
   The circuit  23  further comprises an excitation line  29 , which is provided with two switches  30 ,  31  set in series with respect to one another and supplies electric current for energizing and switching the relay  26  from the first operating position to the second operating position when the switches  30 ,  31  are simultaneously closed. The switch  30  may be switched manually by the driver of the vehicle by means of a corresponding push-button or lever  32  (partially illustrated) located in the cab, whilst the switch  31  is normally open and is switched automatically according to the position signal issued by the sensor  22  in such a way as to close the circuit automatically when the stretches  4   b  and  5  reach the aforesaid predetermined relative reference position. 
   When the vehicle  1  has to circulate on the road, the arm  3  must be set in a position such as to respect the parameters of profile and maximum encumbrance laid down by the highway code ( FIG. 1 ). In order to obtain this result, the driver first operates the cylinders  7   a ,  7   b  and  9  to bring them into respective pre-defined end-of-travel positions and then acts on the device  20  in order to position the rod  14  with respect to the liner  15  in an intermediate position corresponding to the aforesaid predetermined relative reference position between the stretches  4   b  and  5 . 
   In particular, the driver of the vehicle first closes the switch  30  manually to activate the circuit  23  and render the device  20  operative, and then controls the members  16  for actuating the cylinder  8 . When the stretches  4   b  and  5  reach their predetermined relative reference position during actuation of the cylinder  8 , the sensor  22  issues a corresponding position signal that causes switching of the switch  31  to close the line  29  and hence switch the relay  26  to its second operating position. At this point, supply ceases to the solenoid valve  19 , which switches to its disabling position, inhibiting the valve  11  to prevent further actuation of the cylinder  8 , whilst the buzzer  27  starts to go off, indicating to the driver that the cylinder  8  is arrested in the desired intermediate position and that it can no longer be actuated by the members  16 . 
   To render positioning of the cylinders  7   a ,  7   b ,  8 ,  9  and thus of the arm  3  secure, the driver gets down from by the vehicle  1  to close manually a plurality of cocks (not illustrated) associated to the chambers of the cylinders  7   a ,  7   b ,  8 ,  9  to prevent any leakage of oil from the circuit  10 . As an alternative to at least part of the aforesaid cocks, in some solutions of excavating vehicles there are provided, on the chambers of each cylinder, respective safety valves, which are closed automatically by the absence of driving pressure in the circuit  10 . 
   To restore the possibility of actuating the cylinder  8  again by means of the members  16 , the driver must switch the switch  30  so that it opens the circuit. In fact, once the line  29  is opened by this manual command, the relay  26  switches to its first operating position, so that the line  25  no longer supplies the branch in which the buzzer  27  is present, but the branch in which the solenoid C is present, so causing switching of the solenoid valve  19  to its enabling position to render the valve  11  and hence the members  16  once again operative. 
   Finally, from the foregoing it emerges clearly how the device  20  makes it possible to set the arm  3 , and in particular the stretches  4   b  and  5 , in a pre-determined reference position in a precise and practically automatic way, i.e., without the driver having to assess visually the displacement of the arm  3 , in so far as the solenoid valve  19  switches automatically to its disabling position when the sensor  22  detects that the aforesaid reference position has been reached. In addition, when the arm  3  has been positioned in the reference position, the device  20  prevents any further undesirable actuation of the cylinder  8 , which may be due, for example, to accidental maneuvers on the members  16 , in so far as it inhibits the valve  11  and hence driving of the valve  12  up to the moment in which the driver re-enables the possibility of actuating the cylinder  8  manually by opening the switch  30 . 
   The device  20  is simple, in so far as it only requires the use of a simple solenoid valve  19 , and not the use of possible complex mechanical or magnetic arrest or control equipment for arresting the cylinder  8  in the desired position or for inhibiting actuation of the cylinder  8  itself. 
   Finally, from the foregoing it emerges clearly that modifications and variations can be made to the device  20  described herein with reference to the attached figures, without thereby departing from the scope of protection of the present invention. 
   In particular, there could be provided means for disabling or arresting the cylinder  8  that are different from the solenoid valve  19  and the circuit  23  described and schematically illustrated herein by way of example. 
   In addition, the sensor  22  could be different from the one indicated; for instance, it could be an angular sensor of a continuous type and/or could be associated to the cylinder  8  for detecting the relative position between the rod  14  and the liner  15 , instead of detecting the relative position of the stretches  4   b  and  5  directly. 
   Finally, the acoustic-signaling device  27  could be replaced by a luminous signaling device.