Patent Description:
The present invention relates to a crawler vehicle for the preparation of ski runs.

Generally, a crawler vehicle of the type identified above comprises a frame; a cabin mounted on the frame; a propulsion system mounted on the frame; driving wheels actuated by the propulsion system; and tools supplied by the propulsion system.

When the crawler vehicle is used for the preparation of particularly steep ski runs, the crawler vehicle is equipped with a winch, which is mounted on the frame and comprises an arm configured to guide and selectively orient the cable of the winch with respect to the frame around a determined axis.

Generally, the arm is rotated around the determined axis so as to control the arm when the free end of the cable of the winch is not anchored to a point outside the crawler vehicle. Generally, when the cable is under tension the arm is left free to orient itself around the axis, thus the arm in this configuration is aligned with the portion of cable outside the arm.

When the direction of the force exerted by the cable on the crawler vehicle does not pass through the barycentre of the crawler vehicle, said force applies a yawing torque to the crawler vehicle. In order to overcome this drawback, document No. <CIT> teaches how to automatically compensate the yawing torque through a torque applied to the arm so as to arrange the arm in a determined position in which the prolongation of the cable outside the crawler vehicle is aligned with the barycentre of the crawler vehicle. Theoretically, in this manner, the yawing torque is eliminated.

The automatic compensation of the yawing torque provides for acquiring the angle of the arm with respect to the frame around the determined axis and the entity of the yawing torque so as to compute and automatically apply the corrective torque so as to compensate at least in part the yawing torque.

The application of the automatic compensation of the yawing torque limits possible beneficial uses thereof.

Document No. <CIT> discloses a further example of a vehicle for the maintenance of ski slopes comprising a winch mounted on a frame and including a winding drum and a winding motor associated with the drum, and a cable to be unwound and wound around the drum by the winding motor so as to generate a compensation for the pulling torque of the vehicle.

The object of the present invention is to provide a crawler vehicle for the preparation of ski runs which reduces the drawbacks of the known art highlighted herein.

In accordance with the present invention, a crawler vehicle for the preparation of ski runs is realised; the crawler vehicle comprising:.

In this manner, it is possible to control the yawing torque in any operating step and use it for driving the crawler vehicle, if necessary.

Furthermore, it is possible to transmit to the arm respective torques in opposite direction around the determined axis.

More specifically, each actuator is configured to transmit a variable torque between a minimum and a maximum value, so as to adjust the torque transmitted to the arm.

Practically, each actuator is a two-way flow hydraulic motor supplied with a pressure variable between a minimum and a maximum value.

In this manner, it is possible to selectively vary the direction of the torque transmitted to the arm.

With the purpose to control the at least one hydraulic motor, the actuating system comprises a hydraulic circuit supplied by a pressure source and comprises a pressure regulating valve, so as to adjust the force transmitted by the at least one actuator.

In particular, the actuating system comprises for each hydraulic motor a direction control valve for selectively excluding the supply to the respective hydraulic motor or supplying the respective hydraulic motor in a first direction of flow or supplying the respective hydraulic motor in a second direction of flow opposite to the first direction of flow.

In this manner, it is simultaneously possible to selectively eliminate the torque transmitted by the at least one actuator to the arm and/or to selectively vary the direction of said torque so as to control the steering of the crawler vehicle.

In particular, the control device is configured to manually control the pressure regulating valve and to control the direction control valves.

In this manner, an operator of the crawler vehicle can manually control the actuating system and set the desired operating mode.

In particular, the control device comprises a joystick, so as to allow the operator of the crawler vehicle to control the actuating system in a simple and intuitive manner.

A further object of the present invention is to provide a method to control the winch of the crawler vehicle which reduces the drawbacks highlighted herein of the known art.

In accordance with the present invention, a method to control the winch of the crawler vehicle as previously described is provided, the method comprising:.

Thanks to such method, it is possible to allow a free rotation of the arm around the determined axis.

In accordance with the present invention, a further method to control the winch of the crawler vehicle as previously described is provided, the method comprising:.

In this manner, it is possible to lock the position of the arm with respect to the frame. In the case where the crawler vehicle moves downhill, such method allows maintaining the crawler vehicle aligned with the forward direction preventing the crawler vehicle from yawing.

Further characteristics and advantages of the present invention will be apparent from the following description of a non-limiting example embodiment, with reference to the attached figures, wherein:.

With reference to <FIG>, reference numeral <NUM> indicates, as a whole, a crawler vehicle for the preparation of ski runs. The crawler vehicle <NUM> comprises a frame <NUM>; a track <NUM> (<FIG> and <FIG>); a track <NUM>; a driving wheel <NUM> (<FIG> and <FIG>) and a driving wheel <NUM> independent of one another and coupled to the track <NUM> (<FIG> and <FIG>) and to the track <NUM> respectively; a plurality of tools <NUM> hydraulically actuated and connected to the frame <NUM>; a cabin <NUM> mounted on the frame <NUM>; and a user interface <NUM> arranged inside the cabin <NUM>.

In particular, the tools <NUM> comprise a miller <NUM> connected in movable manner to the frame <NUM>; a shovel <NUM> connected in movable manner to the frame <NUM>; and a winch <NUM> mounted on the frame <NUM> for selectively unwinding and winding a cable <NUM> that can be anchored to a point <NUM> (<FIG> and <FIG>) outside the crawler vehicle <NUM>.

In accordance with a non-limiting embodiment of the present invention, the cabin <NUM> is arranged at the front of the crawler vehicle <NUM> and faces the shovel <NUM>. In such configuration, the winch <NUM> comprises a drum <NUM> which swivels around a rotation axis A1 for the winding and unwinding of the cable <NUM> and is arranged at the back of the crawler vehicle <NUM>, behind the cabin <NUM>.

Furthermore, the crawler vehicle <NUM> comprises an arm <NUM>, which is mounted swivelling with respect to the frame <NUM> around a determined axis A2, and is configured to guide the cable <NUM>; an actuating system <NUM> of the arm <NUM> around the determined axis A2; and a control device <NUM> of the actuating system <NUM> of the arm <NUM> for selectively setting one of the following operating modes when the cable <NUM> is under tension:.

More specifically, the crawler vehicle <NUM> comprises a supporting structure <NUM> fixed to the frame <NUM>, which supports the drum <NUM> of the winch <NUM> and supports in a swivelling manner the arm <NUM>; and a series of idle pulleys <NUM>, <NUM>, <NUM> and <NUM> which are mounted in a swivelling manner on the supporting structure <NUM> and on the arm <NUM> and have the function of guiding the cable <NUM> along a determined path.

The actuating system <NUM> comprises two actuators <NUM> and <NUM> (<FIG> and <FIG>) coupled to the arm <NUM> for selectively transmitting to the arm <NUM> respective torques around the determined axis A2.

In accordance with further embodiments, the number of the actuators can vary By way of example, the actuating system <NUM> can comprise four actuators.

The control device <NUM> uses the user interface <NUM> for allowing an operator U of the crawler vehicle <NUM> to control the actuating system <NUM> and comprises a joystick <NUM> controllable by said operator U.

With reference to <FIG> and <FIG>, the crawler vehicle <NUM> has a barycentre C, which is arranged at a distance from the determined axis A2.

In the case described and illustrated herein, the actuators <NUM> and <NUM> are supported by the supporting structure <NUM> and are arranged on opposite sides with respect to the arm <NUM>.

In particular, the actuators <NUM> and <NUM> are two-way flow hydraulic motors supplied with a pressure variable between a minimum and a maximum value so as to transmit a variable torque between a minimum and a maximum value.

With reference to <FIG>, the actuating system <NUM> comprises a hydraulic circuit <NUM>, which is supplied by a pressure source <NUM> and comprises a pressure regulating valve <NUM> for adjusting the supply pressure of each actuator <NUM> and <NUM> between a minimum and a maximum value.

Furthermore, the actuating system <NUM> comprises a direction control valve <NUM> and a direction control valve <NUM>, each of which is configured to selectively exclude the supply to the respective actuator <NUM>, <NUM> or to supply the respective actuator <NUM>, <NUM> in a first direction of flow or to supply the respective actuator <NUM>, <NUM> in a second direction of flow opposite to the first direction of flow.

In particular, the actuating system comprises control modules <NUM>, <NUM> and <NUM>, which are configured to control the pressure regulating valve <NUM>, the direction control valve <NUM> and the direction control valve <NUM> respectively, depending on the commands given by the joystick <NUM> and on the operating mode selected.

More specifically, each control module <NUM>, <NUM>, <NUM> is configured to control the respective valve <NUM>, <NUM>, <NUM> so that the commands given by the joystick <NUM> supply the actuators <NUM> and <NUM> with a pressure and a direction of flow suitable to the selected operating mode.

In use and with reference to <FIG>, when the cable <NUM> is under tension, the operator U of the crawler vehicle <NUM> through the joystick <NUM> selects the desired operating mode depending on the particular operational needs and on the driving sensations.

With the purpose to allow the free rotation of the arm <NUM> around the determined axis A2, in order to arrange the arm <NUM> aligned with the portion of cable <NUM> outside the arm <NUM>, the operator U of the crawler vehicle <NUM> controls the joystick <NUM>, actuating the pressure regulating valve <NUM> (<FIG>) so as to apply a minimum torque to the arm <NUM> through each actuator <NUM>, <NUM> and opposite to the minimum torque applied by the other actuator <NUM>, <NUM>.

In the case where the operator U of the crawler vehicle <NUM> wants to compensate the yawing torque exerted by the cable <NUM> under tension on the crawler vehicle <NUM>, said operator U controls the joystick <NUM> so as to adjust, through the pressure regulating valve <NUM> (<FIG>), the intensity of the torque exerted by each actuator <NUM>, <NUM> on the arm <NUM> and, through each direction control valve <NUM>, <NUM> (<FIG>), the direction of the torque exerted by the respective actuator <NUM>, <NUM> on the arm <NUM>. In such circumstances, the actuators <NUM> and <NUM> apply on the arm <NUM> a torque concordant in direction with the yawing torque and the arm <NUM> is rotated around the determined axis A2 so as to substantially align the portion of cable <NUM> outside the arm <NUM> with the barycentre C of the crawler vehicle <NUM>. This operation is repeated by the operator until the latter deems it necessary.

With reference to <FIG>, in the case where the operator U of the crawler vehicle <NUM> wants to steer the crawler vehicle <NUM> in a desired steering direction, said operator U controls the joystick <NUM> so that the actuators <NUM> and <NUM> apply on the arm <NUM> a torque opposite in direction to the direction of the desired steering and with an intensity manually adjusted. In such circumstances, the arm <NUM> is rotated around the determined axis A2 so as to follow the yaw of the crawler vehicle <NUM> around the barycentre C.

In the case where the operator U of the crawler vehicle <NUM> wants to move the crawler vehicle <NUM> forward in a substantially rectilinear direction, said operator U controls the joystick <NUM> so as to apply a maximum torque to the arm <NUM> through each actuator <NUM>, <NUM> and opposite to the maximum torque applied by the other actuator <NUM>, <NUM>. More specifically, the pressure regulating valve <NUM> (<FIG>) is adjusted so as to supply with the maximum pressure the actuators <NUM> and <NUM> and the direction control valves <NUM> and <NUM> (<FIG>) are adjusted so that the respective actuators <NUM> and <NUM> apply on the arm <NUM> torques of opposite direction. In such circumstances, the arm <NUM> is substantially locked with respect to the frame <NUM> in the forward direction of the crawler vehicle <NUM>. The operating mode described above is particularly indicated in the case where the crawler vehicle <NUM> moves downhill, allowing maintaining the crawler vehicle <NUM> aligned with the forward direction and preventing unwanted yaws of the crawler vehicle <NUM>.

Claim 1:
A crawler vehicle for the preparation of ski runs; the crawler vehicle (<NUM>) comprising:
- a frame (<NUM>);
- a winch (<NUM>) mounted on the frame (<NUM>) for selectively unwinding and winding a cable (<NUM>) that can be anchored to a point (<NUM>) outside the crawler vehicle (<NUM>);
- an arm (<NUM>), which is mounted swivelling with respect to the frame (<NUM>) around a determined axis (A2), and is configured to guide the cable (<NUM>);
- an actuating system (<NUM>) of the arm (<NUM>) around the determined axis (A2), wherein the actuating system (<NUM>) comprises two actuators (<NUM>, <NUM>) coupled to the arm (<NUM>) for selectively transmitting to the arm (<NUM>) respective torques in opposite directions around the determined axis (A2);
- a control device (<NUM>) of the actuating system (<NUM>) of the arm (<NUM>) to select an operating mode between the operating modes of:
- allowing the free rotation of the arm (<NUM>) around the determined axis (A2) when the cable (<NUM>) is under tension;
- rotating the arm (<NUM>) around the determined axis (A2) when the cable (<NUM>) is under tension;
- locking the position of the arm (<NUM>) with respect to the frame (<NUM>) when the cable (<NUM>) is under tension.