EP3593871A1

EP3593871A1 - Automatic tennis court maintenance system

Info

Publication number: EP3593871A1
Application number: EP19185366.2A
Authority: EP
Inventors: Giovanni Bertoni; Alessandro Martini
Original assignee: Stm Products Srl
Current assignee: Stm Products Srl
Priority date: 2018-07-11
Filing date: 2019-07-10
Publication date: 2020-01-15
Anticipated expiration: 2039-07-10
Also published as: IT201800007106A1; EP3593871B1; ES2869242T3

Abstract

The invention relates to an automatic maintenance system for a tennis court which comprises: (a) one or two robots (2, 2a, 2b, 2c) with one or more maintenance elements of the tennis court (34, 46; 36, 38; 40, 42; 62; 64, 68; 70, 72) which has a width which corresponds at least to the extension of the end line, preferably at the distance of the double posts which support the court net and which is equipped with motion means (4, 6, 8, 10) to move said robot (2, 2a, 2b, 2c) and with a control unit (12) for controlling said maintenance elements of the tennis court and said motion means; (b) a supplying station for each robot locatable/located behind the end line of the tennis court; and (c) a communication device (28) for communication with said control unit (12) to allow remote management of said court maintenance elements (36, 38; 40, 42; 62; 64, 68; 70, 72) and the motion means. The supplying station comprises: (α) fixing means, preferably magnetic hooks, to be able to reversibly attach said tarpaulin (34) which in this regard is equipped with respective second fixing means (16) which can be coupled to said first fixing means; and/or (β) in case a wetting unit (64, 68) is present, a hydraulic attachment for filling the water tank; and/or (γ) devices for charging the battery(s) within the robot. Said tennis court maintenance element(s) is/are selected between a court covering unit containing a rolled up tarpaulin (34) on a relative axis (46) which can be actuated with a rotation movement, a grass cutting unit (38), a line tracing unit (40, 42), a smoothing unit (62), a wetting unit (68, 64), a cleaning unit (70, 72) and combinations thereof. The invention also relates to a tennis court equipped with the aforementioned system and a relative process for the maintenance of a tennis court.

Description

TECHNICAL FIELD

The invention relates to an automatic system for the maintenance of a tennis court and can be adapted to the various types of courts: grass, clay and concrete courts. Ordinary maintenance comprises court covering with a tarpaulin for all types of surfaces, cutting grass and white lines tracing for grass courts, smoothing and wetting for clay courts and cleaning from debris and water for the concrete courts. A further maintenance work is the brushing of the white lines of the court.

BACKGROUND ART

Tennis courts need continuous maintenance. The following tasks are periodically performed manually on the tennis courts: the tennis court covering with a tarpaulin in case of rain, smoothing and water spraying on the clay court, which is generally made between one set and the other or at end of a game, cutting the grass and the white lines tracing of the grass court that is usually performed outside the opening hours of the courts, cleaning the surface of the concrete court that could also be performed to aspirate any rainwater left on the surface. It is also necessary to brush white lines, especially on clay courts.
These tasks are performed manually with a great deal of human resources and with proper tools, such as brooms, tarpaulin, water hose, lawn mowers or a machine to be manually pushed to trace the white lines as described in the French document FR 2 586 358 A1 .
The state of the art knows some devices for covering surfaces, in particular also a tennis court, with a protection, as described in the documents WO 2010/054960 A1 , FR 2 803 769 A1 , US 3,108,804 A , WO 2014/068131 A1 and FR 2 743 502 A1 . All these devices do not allow other maintenance of the tennis court.

DISCLOSURE OF THE INVENTION

The invention aims to propose a flexible, reliable and economical automatic system from a construction point of view that is able to carry out maintenance tasks even during a tennis tournament (e.g. court covering) and between a set and the other (e.g. smoothing and wetting the court).
The purpose is achieved by means of an automatic maintenance system for a tennis court which comprises:

(a) at least one robot comprising a housing containing one or more tennis court maintenance elements which has a width corresponding at least to the extension of the end line, preferably to the distance of the two double posts supporting the court net, and which is equipped with
- (a1) motion means for moving said robot;
- (a2) a control unit for controlling said tennis court maintenance elements and said motion means,
wherein said tennis court maintenance element(s) is/are selected between a court covering unit containing a rolled up tarpaulin on a relative axis which can be actuated with a rotation movement, a grass cutting unit, a line tracing unit, a smoothing unit, a wetting unit, a cleaning unit and combinations thereof; and
(b) a communication device for communication with said control unit to allow remote management of said court maintenance elements and motion means. The automatic system is characterized in that it further comprises
(c) a supplying station for each robot locatable/located behind the end line of the tennis court;
wherein the supplying station comprises:
- (α) fixing means, preferably magnetic hooks, to be able to reversibly attach said tarpaulin which in this regard is equipped with respective second fixing means which can be coupled to said first fixing means; and/or
- (β) in the case of the presence of a wetting unit, a hydraulic attachment for filling the water tank; and/or
- (γ) devices for charging the battery(s) inside the robot.

Advantageously, said motion means are rollers and/or wheels of which at least one can be actuated to cause the movement of the robot. Due to the motion means, the robot can move forward from the supplying station or from the court end towards the net and, backwards, from the net towards the supplying station or the court end, and, optionally laterally, if necessary.
In an exemplary embodiment the supplying station can comprise an automatic system for supplying water and electricity and blocking the robot when it is idle at the court end.
The communication device can be a PC, or a tablet or remote control equipped with specific software to communicate.
Advantageously, the robot incorporates the maintenance units necessary for the maintenance of the specific type of surface, namely the following tasks: the court covering with a tarpaulin, the wetting of the court, the grass cutting (e.g. with one or two lawn mowers), the line tracing with one or more tracers, smoothing and cleaning. In a preferred variant embodiment of the invention, the robot also comprises a maintenance unit necessary for brushing the white lines. Such a robot can perform all the maintenance tasks described above relative to an area which in particular goes from the two double posts supporting the net to the end court fence. Advantageously, the supplying station is located near the fence. Preferably the communication device is a device suitable for two-way communication between a computer and the robot.
The control unit installed on the robot and the communication device, for example a PC or tablet or remote control communicate in a two-way manner.
In preferred variant embodiments of the invention, the robot has limited shape and dimensions so as to occupy as little space as possible when it is positioned in the supplying station at the court end. Advantageously, the control unit comprises a data transmission and reception device for remote management of the robot. Preferably, one or more sensors which are installed at strategic points of the robot are connected to the control unit, selected from: sensors to determine exactly the position of the robot, such as ultrasonic and/or optical and/or electromechanical sensors; volumetric sensors or other proximity sensors to detect any obstacles of things and/or people when the robot is moving; an anemometer and a humidity sensor to automatically activate the rewinding of the tarpaulin in case of wind that exceeds a certain speed or to activate the unfolding of the tarpaulin in case of rain.
In a variant embodiment of the invention, with the PC or tablet or remote control it is possible to schedule the tasks of the robot and define its behaviour in case of activation of the humidity sensors and anemometer.
Preferably, the covering unit further comprises a bar with toothed wheels and a counter-bar between which the tarpaulin with slots passes during its unfolding or winding. The presence of such bars allows to keep the tarpaulin stretched. Advantageously, the covering unit comprises a tarpaulin cleaning system which is installed where the tarpaulin enters the unit, such as for example a pair of brushes and/or a pair of aspirators between which the tarpaulin passes during its unfolding or winding. The tarpaulin is therefore cleaned and the entrance of debris that could compromise the winding is prevented. The covering unit can optionally comprise a lateral support roller with the function of supporting the weight of the tarpaulin and its axis and keeping the tarpaulin pressed towards its own axis for a correct winding. Advantageously, the grass cutting unit contains one or two lawn mowers and a tank which collects the cut grass equipped with a level controller. Preferably, this unit moves along dedicated rails and is able to mow the grass from the net posts to the court end fence. Preferably, a line tracing unit is associated with the grass cutting unit, since it uses the same displacement on rails of the grass cutting unit, to trace the white lines of the playing area. The guides advantageously allow a movement along a distance corresponding at least to the width of the playing area or to the distance between the two double posts.
In a preferred variant of the invention, the line tracing unit comprises a dye dispensing device, in particular of chalk powder or the like, which is fed from a tank containing said powder and which is optionally provided with a level controller.
Advantageously, the smoothing unit is a panel with brushes designed to be vibrated. The vibrating brushes allow to obtain a homogeneous surface of a clay tennis court and at the same time clean the white lines from the ground. The area concerned is preferably from the net posts to the court end fence.
In an advantageous variant embodiment of the invention, the wetting unit comprises a water tank optionally equipped with a level controller, and a sprayer to be able to wet the court from the net posts to the court end fence.
The cleaning unit for concrete tennis courts preferably provides one or two aspirators to remove both small debris and any water present in the court. The aspirator advantageously collects what is aspirated into a tank optionally equipped with a level controller.
Advantageously, the white line brushing unit within the robot is composed of a shaft with a plurality, for example nine, motorized circular brushes dimensioned to clean the vertical and horizontal lines of the court when the robot moves from the supplying station to the net or vice versa. In a particular variant embodiment of the invention, the circular brushes operate only when they are positioned at the white vertical or horizontal lines. The same circular brushes are advantageously blocked around their own axis when they are not positioned at the white lines thus levelling the surface of the court. Therefore, with a single shaft with motorized circular brushes it is possible both to brush the white lines and to level the surface. The levelling area is preferably from the double posts to the supplying station. Advantageously, the robot according to the invention always comprises, regardless of the type of surface of the court, a covering unit. In the case of clay courts, the wetting and smoothing units can be associated. Advantageously, a unit is also associated for brushing the white lines. In the case of grass courts, the grass cutting, and line tracing units can be associated. In the case of concrete courts, the cleaning unit can be associated. Other combinations are conceivable, some of which are found in Table 2 below.
Advantageously, the robot is equipped with an electronic control unit (control unit) which supervises all its movements, all the tasks of the maintenance units and remote communication with a remote manager, such as a PC, a tablet or a remote control. Preferably, one or more batteries power all the electrical and electronic components.
In a preferred variant embodiment of the invention, the supplying station for the robot is located at the court end near the fence. The supplying station advantageously comprises first fixing means, preferably magnetic hooks, to be able to reversibly attach the tarpaulin which in this regard is equipped with respective second fixing means which can be coupled to the first fixing means and to hook the same robot. Such a fixing allows to hold one end of the tarpaulin to be able to unroll and lay it out on the court by moving the robot towards the court net.
The robot, when idle, is preferably located at the court end in the supplying station near the fence. The supplying station in this regard is advantageously equipped with a magnetic blocking system of the tarpaulin and the robot.
In the presence of a wetting unit, the supplying station comprises a hydraulic attachment for filling, preferably automatic, of the water tank.
Preferably, the robot comprises one or more batteries which power the components contained and the supplying station comprises a device for charging the battery(s) inside the robot. The batteries power the electrical and electronic components. The batteries can be induction charged in the supplying station.
In a further advantageous variant of the invention, the communication device for communication with the control unit is a computer, a PC, a tablet or a remote control for communicating remotely with the robot to manage its movements and the different court maintenance units. In this way it is possible to move it remotely from the supplying station to the court net and vice versa and to actuate or stop the various maintenance units.
The communication between computer, PC, tablet or remote control and the robot is advantageously two-way so that messages of any malfunctions and the status of its components such as tank levels, battery(s) charge level, etc. can be received on the computer, PC, tablet or remote control.
Through the computer, PC, tablet or remote control the robot can for example be activated online, or according to a weekly schedule, or automatically in reaction to signals related to sensors (such as anemometers or humidity sensors as will be explained later).
The automatic maintenance system of a tennis court according to the invention is therefore composed of three parts: the actual court treatment part performed by the robot, the shelter part as a rest and supplying station of the robot and a remote system management part.
In a purely exemplary form, the system according to the invention is composed of two robots, automatic supplying and blocking devices of the robot when it is located in the supplying station and a PC or tablet or remote control for remote management of the system. To facilitate the remote management of the robot, a camera can be installed on the tennis court fence so as to display the robot's movements.
A further aspect of the invention relates to a tennis court which is equipped with a net and an automatic maintenance system for a tennis court according to the invention with a robot and a supplying station for each side of the court. Advantageously, the automatic supplying station is equipped for an automatic supplying of water and electricity and with fixing means of the tarpaulin. Advantageously, a single communication system is provided, for example a PC, tablet or remote control to manage remote communication. Advantageously, the single communication system remotely manages all the robots of a tennis club.
The last aspect of the invention relates to a maintenance process of a tennis court comprising the following phases:

(i) making available a maintenance system of a tennis court according to the invention;
(ii) in the case of court covering, activation of the covering unit and court covering from the supplying station to the tennis court net with the tarpaulin hooked to the supplying station;
(iii) in the case of grass cutting, activation of the grass cutting unit and movement of the robot from the supplying station to the court net;
(iv) in the case of line tracing, activation of the tracing unit and tracing of horizontal and vertical lines of the court according to a pre-established program;
(v) in the case of court smoothing, activation of the smoothing unit and movement of the robot from the supplying station to the court net;
(vi) in the case of court wetting; activation of the wetting unit and movement of the robot from the supplying station to the court net;
(vi) in the case of court cleaning; activation of the cleaning unit and movement of the robot from the supplying station to the court net.

Optionally in the case of brushing the white lines of the court, the process according to the invention comprises step (viii) of the activation of a brushing unit and movement of the robot from the supplying station to the court net.
In a preferred variant of the invention, a combined court smoothing and white lines brushing unit is provided. Such a unit can operate with circular brushes as shown above.
Preferably, during phases (iii) to (vii), the tarpaulin is detached from the supplying station ensuring that the tarpaulin remains wound within the robot.
With the description of preferred embodiments of the invention, possible variant embodiments are illustrated below to perform phases (ii) to (vii) which can be performed and combined independently of one another.
The process can be integrated by returning the robot to the supplying station where the tarpaulin can be fixed, the batteries recharged and/or the water tank of the wetting unit filled if present. Also conceivable are devices to fill the dye tank (e.g. gypsum powder) and/or empty the aspirator and lawn mower tanks. All these steps operate preferably automatically. Advantageously, levelling the surface and brushing the lines takes place under electronic control with the use of ultrasonic, optical or electromechanical sensors to ensure perfect levelling and brushing.
Preferably, cleaning the concrete courts or the like takes place under electronic control with the use of ultrasonic, optical or electromechanical sensors to ensure the court surface cleaning that goes from the double posts to the court end.
Advantageously, grass cutting takes place under electronic control with the use of ultrasonic, optical or electromechanical sensors to determine the exact position of the lawn mower while the robot moves to ensure a perfect cutting of the grass from the double posts to the court end. Preferably, court wetting is regulated by a PC or tablet or remote control on which the litres of water to be sprayed on the playing area are defined. If necessary, the robot can automatically be supplied with water several times in the supplying station, spraying the court evenly. The movement of the robot takes place advantageously under electronic control with the use of ultrasonic, optical or electromechanical sensors to exactly determine its position to be able to wet the court from the double posts to the court end with the same amount of water per m². The batteries can eventually be charged by induction. Advantageously, the various supplies take place automatically.
The features described for one aspect of the invention may be transferred, mutatis mutandis, on any other aspect of the invention.
To sum up, it can be noted that the invention achieves the intended object, and in particular provides a system for the maintenance of a tennis court which in a flexible manner allows to perform all the tasks mentioned at the beginning with reference to the technical field and which employs little time and staff as it can be managed independently and automatically.
To the knowledge of the applicant, currently the state of the art does not know systems for automatically managing the maintenance of a tennis court, in particular which manage to combine all the maintenance tasks described above and necessary for the individual surface types comfortably within a single system.
Said objects and advantages will be better highlighted during the description of preferred embodiment examples of the invention given by way of not limiting example.
Variant embodiments of the invention are the object of the dependent claims. The description of preferred embodiment examples of the automatic maintenance system of a tennis court, of the tennis court and the process for the maintenance of a tennis court according to the invention is given by way of not limiting example with reference to the appended drawings.

DESCRIPTION OF PREFERRED EMBODIMENTS

Fig. 1: illustrates in a perspective view a maintenance system of a tennis court according to the invention with the robot outside the supplying station.
Fig. 2: illustrates a perspective view of the maintenance system of a tennis court of figure 1 with the robot in its supplying station.
Fig. 3: illustrates in a perspective view a tennis court with two robots according to the invention positioned at the court net.
Fig. 4: illustrates a perspective view of a tennis court with two robots according to the invention, one positioned at the court net and the other in the supplying station.
Fig. 5: illustrates in a cross section a first exemplary embodiment of a robot suitable for grass courts.
Fig. 6: illustrates in a cross section a second exemplary embodiment of a robot suitable for clay courts.
Fig. 7: illustrates in a cross section a third exemplary embodiment of a robot suitable for concrete courts.

Fig. 1 illustrates in a perspective view a maintenance system 2 of a tennis court according to the invention outside its supplying station. On the front side of the robot 2 wheels placed laterally 4 and centrally 6 are provided. Under the robot 2 a median roller wheel 8 and a rear roller wheel 10 are provided. The wheels can have for example a diameter of 4 cm. On both short sides lateral switchboards 12 are provided. In the central part 14 the robot has for example a height of 28 cm and a depth of 69 cm. The robot 2 is housed in the supplying station on anchoring elements 16 and spacers 18 placed on the fence 20 with the protection net 22 for the recovery of the tennis balls. On the same fence 20 the three court end judge chairs 24 are installed. The three chairs 24 do not move with the robot 2. A user 26 manages the robot 2 with a computer 28 with a dedicated software.
Fig. 2 illustrates in a perspective view the maintenance system of a tennis court of figure 1 in its supplying station. The robot 2 is positioned above spacers 18 and attached to the anchoring elements (not visible) and below the judge chairs 24.
Fig. 3 illustrates a perspective view of a tennis court with two robots 2 according to the invention positioned at the court net 32. On the left a part 30a of the grass tennis court can be seen. On the left side of court 30a the tarpaulin was not laid out, while the robot 2 on the right side of court 30b covered it with the tarpaulin 34.
Fig. 4 illustrates in a perspective view a tennis court with two robots 2 according to the invention, one positioned at the court net 32 and the other in its supplying station. Only on one half of the court the tarpaulin 34 was laid out.
Fig. 5 illustrates in a cross section a first exemplary embodiment of a robot 2a suitable for grass courts. A grass tank 36, a lawn mower 38, a line tracer 40 supplied by a tank 42 containing gypsum powder, a level controller 44 can be seen. The tarpaulin 34 is wound on an axis 46. The axis can have in an exemplary form a diameter of 19 cm and the tarpaulin a height of 1 mm, a width of about 13 m and a depth of about 19 m. A support bar 48 helps to support the tarpaulin 34. A bar 50 with toothed wheels together with a counter-bar 52 guides and drags the tarpaulin 34 during the unfolding and winding. To clean the passing tarpaulin 34 brushes 54 and aspirators 56 are provided. The covering unit T is in a first compartment 58 of the robot and the module for the maintenance of grass courts E in a second compartment 60a.
Fig. 6 illustrates a cross section of a second exemplary embodiment of a robot 2b suitable for clay courts. Also in this case the robot 2b is composed of two compartments, and precisely of the covering unit T in its compartment 58, which corresponds to that described with reference to figure 5, and of a second compartment 60b with the module for maintenance of clay courts TB. A panel, that is a shaft with brushes 62 to smooth the clay, a water tank 64 with a respective water level controller 66 and water sprayers 68 can be seen. The brushes 62 can also be used to brush the white lines.
Fig. 7 illustrates in a cross section a third exemplary embodiment of a robot 2c suitable for concrete courts. Also, in this case the robot 2c is composed of two compartments, and precisely of the covering unit T in its compartment 58, which corresponds to that described with reference to figure 5, and a second compartment 60c with the module for the maintenance of concrete courts C. Aspirators 70, a tank 72 for collecting dust and water aspirated and a level controller 74 within the tank 72 can be seen.
A first 58 and a second compartment 60a, 60b and 60c respectively, create the housing of the robot which contains the relative maintenance elements.
The central part of the robot 2 is located between two switchboards 12. All the long internal components of the central part, except for the tarpaulin, are divided into five parts. The robot from the side view (figures in section from 5 to 7), is divided into two compartments, front 60a, 60b, 60c and rear 58. In the rear compartment 58 the module for winding the tarpaulin 34 is installed and in the front compartment 60a, 60b, 60c one of the three different court maintenance modules is alternatively installed which vary according to the surface of the tennis court: grass, clay or concrete.
The movement of the robot 2, 2a, 2b, 2c is electronically controlled, but other forms of actuation are also conceivable. Its structure has roughly, in section, the shape of a rectangular trapezoid to occupy the court area as little as possible when it is positioned in the supplying station.
The system has been designed in a modular structure and segmented into five parts to facilitate transport, installation and maintenance. Shapes and dimensions of the housing, as well as the number of segments, can vary without departing from the scope of the invention. The housing can be divided into compartments.
In the presented exemplary embodiments, the robot 2 lies on three wheels 6, 4 in the front part and two roller wheels, a central one 8 and a rear one 10. The three front wheels 6, 4 and the rear roller wheel 10 have the function of supporting the robot 2.
The central roller wheel 8, in addition to supporting the robot 2, serves to move the same robot back and forth. The central roller wheel 8 is therefore motorized. The two lateral segments are independent so that the direction of the robot 2 can also be adjusted laterally. Obviously other configurations of wheels or rollers or movement systems are conceivable which the person skilled in the art easily identifies with his/her general knowledge.

Depending on the type of surface of the tennis court, the system comprises the following maintenance units (table 1):

Table 1

Tasks to be done	Grass courts	Clay courts	Concrete courts
Court covering	X	X	X
Grass cutting	X
Lines tracing	X
Surface smoothing		X
White line brushing		X
Wetting		X
Cleaning			X
Maintenance modules	T + E	T + TB	T + C

The individual tasks that may be provided by the maintenance system of a tennis court according to the invention and which can be combined in various ways within the system will be described below.

Court covering

The system 2, 2a, 2b, 2c blocks the tarpaulin 34 with magnetic hooks (not shown) against the anchoring element 16 of the supplying station. The robot 2, 2a, 2b, 2c for unfolding the tarpaulin 34 moves towards the net 32 and at the same time rotates the bar 50 with toothed wheels. The unfolding of the tarpaulin 34 takes place, therefore, under the control of the toothed-wheel bar 50 in order to prevent the unfolding from being affected by tensions on the tarpaulin 34 itself. The robot proceeds and stops when the net 32 is reached, then returns to the supplying station after a certain period of absence of rain (detected by means of relative rain sensors not represented), or by means of a remote command from a computer. If an anemometer (not represented) detects a wind speed greater than a given value, court covering can be disabled automatically.
The robot 2, 2a, 2b, 2c to rewind the tarpaulin 34, returns to its supplying station by activating the motorized axis 46 of the tarpaulin with a slight delay. In this way the rewinding takes place under the control of the toothed-wheel bar 50 preventing external tensions on the tarpaulin.
When the two robots 2 provided on a court have unwound their tarpaulins 34 and have reached the net 32 of the court, the court area, which goes from the two net posts to the court end, will be completely sealed from rain.
The tarpaulin 34 has in exemplary form the thickness of 1 mm or less and can be in elastic rubber or similar materials to prevent creases and wrinkles. Some slots are positioned on the lateral parts of the tarpaulin 34 which slide on the toothed wheels of the roller 50 to ensure the correct winding of the tarpaulin 34 around its own axis 46. The tarpaulin entering its compartment 58 is cleaned by the external brushes 54 and by two internal aspirators 56 to prevent sand, soil, grass from interfering with its winding around the axis 46.

Grass cutting

The robot 2a unblocks the tarpaulin 34 from its magnetic hooks to prevent the unfolding thereof and proceeds step by step towards the net 32. During each step it stops and the lawn mower 38 moves from side to side on its rails cutting the grass from one post to another and to the court end. Once the task is finished, the robot 2a returns to its supplying station. Other configurations and numbers of lawn mowers are conceivable.

White lines tracing

The robot 2a unblocks the tarpaulin 34 from its magnetic hooks to prevent the unfolding thereof and proceeds step by step to the court net 32. During each step it stops and the line tracers 40 move from side to side on the rails of the lawn mower, tracing the white horizontal lines. Then the robot 2b goes back step by step to its supplying station, tracing the white vertical lines. Each step occurs under electronic control to guarantee perfect tracing. Other algorithms for tracing the horizontal and vertical lines, as described above, or tracing in a single time, for example, according to the operation of ink-jet printers, are conceivable. A level controller 44 reports the level of gypsum in the tank 42.

Court smoothing

The robot 2b unblocks the tarpaulin 34 from its magnetic hooks to prevent it from unfolding. A shaft with brushes 62 is activated on the surface of the court. Then it proceeds to the net 32 levelling the surface of the clay court by means of the vibration of the brushes 62. The levelling of the court is also carried out while the robot 2b returns to its supplying station. The white lines of the court are cleaned by the vibration of the panel.

Court smoothing and line brushing

In another variant, the robot 2b unblocks the tarpaulin 34 from its magnetic hooks to prevent the unfolding thereof. A shaft with brushes 62 is activated on the court surface. It then proceeds to the net 32 levelling the clay court surface and cleaning the lines by means of the rotation of the brushes 62. To properly clean the court lines parallel to the net, the robot stops for about a second.

Court wetting

The robot 2b fills the water tank 64 when it is positioned in the supplying station and unblocks the tarpaulin 34 from its magnetic hooks to prevent the unfolding thereof. Then it proceeds to the net 32 spraying water on the tennis court. In case more water is needed, the robot 2b returns to the supplying station to fill the tank 64. A level controller 66 reports the level in the tank. The court wetting unit can also be provided for grass courts.

Cleaning (aspiration)

The robot 2c unblocks the tarpaulin 34 from its magnetic hooks to prevent the unfolding thereof and proceeds step by step towards the net 32. During each step it stops and the aspirators 70 move from one side to the other cleaning the court from one net post to the other and to the court end. The robot 2c proceeds to the net 32. Once the entire area has been cleaned from water, small debris, sand and dust returns to its supplying station.
A level controller 74 reports the level of material in the tank 72.
In case of lawn mowers, line tracers, brushes, aspirators, different numbers and configurations are conceivable that the person skilled in the art easily chooses with his/her general knowledge.
All the electronic and electrical control, movement and communication components are positioned on both sides in switchboards 12 of the robot 2.
A switchboard 12 comprises in an exemplary form the following main components: a main electronic board that has the control and supervision of all the components of the system, a receiving and transmission unit to be able to communicate with the remote computer, batteries, a video camera, a microphone, an alarm light and buzzer, a humidity sensor, an anemometer and a volumetric sensor for safety reasons. The function of the above-mentioned components not yet illustrated will be explained later.
The supplying station of the robot 2, 2a, 2b, 2c is the space occupied by the system when it is not working, here it comprises three anchoring elements 16 positioned at the end of the tennis court and a series of spacers 18 to keep the system lifted. The number and configuration of anchoring elements and spacers may vary. The three anchoring elements 16 have the following functions: to keep the system blocked when it does not operate through the magnetic hooks at the end of the tennis court, to charge (for example by induction) the batteries from the local power supply network or for example from a solar panel, to load the water in the robot tank and keep the tarpaulin blocked when it has to be unwound.
Safety precautions are provided. The robot 2, 2a, 2b, 2c before starting any task, activates an alarm light and a buzzer for a given time. A volumetric sensor detects that no one is occupying the playing area.
Additional accessories can be provided, such as a microphone used frequently during a tournament, a video camera and other security devices.

The models of the system depend on the embedded task units and the surface of the tennis court. The following table 2 indicates some possible models:

Table 2

task modules	Grass court				Clay court				Concrete court
Covering	X	X	X	X	X	X	X	X	X	X
grass cutting		X		X
line tracing			X	X
smoothing							X	X
line brushing							X	X
wetting						X		X
cleaning										X

During operation, further modifications or variant embodiments not described can be applied to the maintenance system of a tennis court, the tennis court, and to the process for the maintenance of a tennis court, object of the invention. If such modifications or such variants should fall within the scope of the following claims, they should all be considered protected by the present patent.

Claims

Automatic maintenance system of a tennis court (2, 2a, 2b, 2c) comprising:
(a) at least one robot (2, 2a, 2b, 2c) comprising a housing (58, 60a, 60b, 60c) containing one or more tennis court maintenance elements (34, 46; 36, 38; 40, 42; 62; 64, 68; 70, 72) which has a width corresponding at least to the extension of the end line, preferably to the distance of the double posts supporting the court net and which is equipped with
(a1) motion means (4, 6, 8, 10) for moving said robot (2, 2a, 2b, 2c);

(a2) a control unit (12) for controlling said tennis court maintenance elements and said motion means (4, 6, 8, 10),
wherein said tennis court maintenance element(s) is/are selected between a court covering unit containing a rolled up tarpaulin (34) on a relative axis (46) which can be actuated with a rotation movement, a grass cutting unit (38), a line tracing unit (40, 42), a smoothing unit (62), a wetting unit (68, 64), a cleaning unit (70, 72) and combinations thereof; and

(b) a communication device (28) for communication with said control unit (12) to allow remote management of said court maintenance elements (36, 38; 40, 42; 62; 64, 68; 70, 72) and of the motion means (4, 6, 8, 10), characterized in that said automatic maintenance system further comprises

(c) a supplying station for each robot locatable/located behind the end line of the tennis court; wherein said supplying station comprises:
(α) fixing means, preferably magnetic hooks, to be able to reversibly attach said tarpaulin (34) which in this regard is equipped with respective second fixing means (16) which can be coupled to said first fixing means; and/or

(β) in the presence of a wetting unit (64, 68), a hydraulic attachment for filling the water tank; and/or

(γ) devices for charging the battery(s) inside the robot.
Automatic maintenance system of a tennis court (2, 2a, 2b, 2c) according to claim 1 characterized in that said covering unit further comprises a bar (50) with toothed wheels and a counter-bar (52) between which the tarpaulin (34) passes with slots during its unfolding and winding and a cleaning system (54, 56) of the tarpaulin which is installed where the tarpaulin enters the unit, such as a pair of brushes and/or a pair of aspirators between which the tarpaulin passes during its unfolding or winding.
Automatic maintenance system of a tennis court (2, 2a) according to claim 1 or 2 characterized in that said line tracing unit comprises a dye dispensing device (40), in particular gypsum powder or similar, which is fed by a tank (42) containing said powder and which can be moved on respective guides provided for this purpose in said housing (60a) along a distance which corresponds at least to the width of the playing area.
Automatic maintenance system of a tennis court (2, 2b) according to any one of the preceding claims, characterized in that said smoothing unit (62) is a panel with brushes able to be vibrated.
Automatic maintenance system of a tennis court (2, 2c) according to any of the preceding claims characterized in that said cleaning unit (70, 72) comprises at least one aspirator (70) and a tank (72) to collect the aspirated material.
Automatic maintenance system of a tennis court (2, 2a, 2b, 2c) according to any of the preceding claims characterized in that said grass cutting unit (38) comprises one or two lawn mowers, for example in the form of a toothed mowing bar and/or a rotating blade, movable along dedicated rails and a tank to collect the cut grass.
Automatic maintenance system of a tennis court according to any of the preceding claims characterized in that said wetting unit comprises a water tank (64) optionally equipped with a level controller, and a sprayer (68) fed by said water tank (64).
Automatic maintenance system of a tennis court (2, 2a, 2b, 2c) according to any of the preceding claims characterized in that it further comprises a maintenance element of the tennis court which is a white line brushing unit.
Tennis court which is equipped with a net (32) and an automatic maintenance system for a tennis court (2, 2a, 2b, 2c) according to any one of the preceding claims with a robot (2) and a supplying station for each side of the court.
Process for the maintenance of a tennis court comprising the following phases:
(i) making available an automatic maintenance system of a tennis court (2, 2a, 2b, 2c) according to any one of the claims 1 to 8;

(ii) in the case of court covering, activation of the covering unit (T) and court covering from the supplying station to the tennis court net with the tarpaulin (34) hooked to the supplying station;

(iii) in the case of grass cutting, activation of the grass cutting unit (38) and movement of the robot (2a) from the supplying station to the court net;

(iv) in the case of line tracing, activation of the tracing unit (40, 42, 44) and tracing of horizontal and vertical lines of the court according to a pre-established program;

(v) in the case of court smoothing, activation of the smoothing unit (62) and movement of the robot from the supplying station to the court net;

(vi) in the case of court wetting; activation of the wetting unit (68, 64) and movement of the robot from the supplying station to the court net;

(vi) in the case of court cleaning; activation of the cleaning unit (70, 72) and movement of the robot from the supplying station to the court net;
wherein for phases (iii) to (vii) in case of presence of a covering unit (T) the tarpaulin (34) is preferably detached from the supplying station.
Process for the maintenance of a tennis court according to claim 10, characterized in that in step (i) an automatic system according to claim 8 is made available and that the process further comprises the step (viii) of the activation of the brushing unit and movement of the robot from the supplying station to the court net.