The invention concerns a machine particularly fit for the maintenance of sport grounds, able to detect ground depressions and level them by spreading suitable filling material, without modifying the due slopes.
Currently the game ground depressions, caused by settling and treading, are manually filled with a shovel or with a net hauled by a device, and passed over the material previously put down.
For closing small holes the manual intervention is effective, while for the substantial depressions such a intervention requires a lot of time and it would be difficult and inaccurate for obtaining also the modification of the expected slopes.
Document FR 2 653 456 discloses a machine for detecting and levelling ground depressions, by spreading of suitable material, wherein it includes a container provided with a distributing device of the material to be distributed, a rotating spreader placed under said distributing device and a ground touching device fit to operate said distributing device for the automatic spreading of the material in correspondence of the detecting of ground depression.
The purpose of the present invention is to make more precise, more rapid and easy the levelling of game grounds.
The machine according to the invention as defined in claim 1 can be hauled and driven by a small tractor, is equipped with a bucket rotating from the loading to distribution positions of the filling material, with a regulating device of the material to be distributed, with a rotating spreader and with a ground touch device, which provides the automatic material spreading, when a depression of substantial dimensions is detected.
The touch device is adjustable, in such a way to allow the regulation of intervention threshold. In particular it is also possible to spread uniformly the filling material on the whole field, or to repeat this operations with time, without covering and choking the grass, in correspondence of a wide depression.
The invention is described in detail, with reference to the attached drawings in which:
In these figures, numeral 1 indicates the drawbar, which is coupled to a small tractor, numeral 2 a cardan joint shaft, to be connected to the tractor power takeoff, numeral 3 indicates the wheels. Numeral 4 indicates a bucket, supported by articulated arms 5, hinged at 6 to the frame, figure 2.
The arms 5 can be lowered or lifted by means of hydraulic jacks 7, to bring the bucket in loading position, as in figure 1, or in working position, as in figure 2. The filling material, contained in the lifted bucket 4, goes down through a lower opening 8 of this latter, in a controlled way, when a finned distributing cylinder 9 is rotated, figures 2 and 3.
The distributing device 9 is hinged at 10 and is operated by a gearmotor 11, figure 3, by means of a gearing chain 12. When the distributing device 9 is in a stopped position its fins, opportunely disposed, do not allow the material passage.
The material dropping from the distributing device 9 in a controlled way, as further explained, is spread onto the ground by a spreader made up of a finned conic disk 13, figures 2 and 3, that is rotated by means of the shaft 2, connected to the power takeoff of the tractor hauling the machine along the ground to be levelled.
The spreader rotates continuously, while the filling material is dropped from the distributing device 9 only when necessary.
For this purpose a ground touch device is provided so as to locate automatically the zones in which the material has to be deposited. A shaft 14, entirely independent from the examined mobile group, is provided with two wheels 15 at the ends, whose distance determines the width of the ground area where the control is made.
In the central part of the machine two touching wheels 16 are provided that, together with related brackets 17 hinged in 18, lift and lower depending on the conformation of the ground to be levelled. The shaft 14, supporting the two end wheels 15, is supported by brackets 19, hinged in 20.
The touching wheels 16, by means of the oscillating brackets 17 and a base 21 integral therewith, act on a rod 22 that is longitudinally moved on supports 23, as better evident in figure 4 and in the detail of figure 6. On the rod 22 is splined an adjustable sleeve 24, placed in such a way to start up the switch 25, causing the start or the stop of the rotating distributing device 9 and therefore the spreading of the filling material.
For avoiding the spreading of the material also into small diameter holes, the distributing device activation is also checked by a timer, or however by a circuit giving the input only if the touching wheel movement is prolonged for pre-established time.
Varying the position of the sleeve 24 and the timer delay it is possible to define the machine automatic intervention ways, depending on the ground type and on the treatment to be done. In such a way the complete filling of a deep depression can be avoided, avoiding the choking of the grass. It is also possible to spread the filling material onto the whole ground.
Numeral 26 indicates an actuator for the touching device lifting during the machine transfer.
The distributing container of the filling material is constituted by the bucket 4 itself, placed in position over the spreader 13.
The distributing device 9 can be operated by means of a circuit controlled by a sensor, placed in such a way to detect the touching device position.