Abstract:
A pneumatic ball gathering system that clears tennis balls from a tennis court using air supplied to at least one discharge nozzle with optional intervening valves forming a structure that is typically disposed underground and selectively raised to clear balls. In one implementation, the structure is located along one side edge of the tennis court. In an alternate implementation, the structure may be located under the net and be configured with at least one nozzle disposed to direct air in both directions away from the net. A collection trough formed with a slope to cause collated balls to roll downward therein is disposed opposite the at least one nozzle. An optional mechanical conveyor system is placed in the trough to move collected balls to a predetermined location. A vertical conveyor raises balls for discharge into an appropriate container. The system may be used to facilitate drying the court after rain.

Description:
RELATED APPLICATIONS 
       [0001]    This application is a Continuation-in-Part of application Ser. No. 14/640,803 filed Mar. 6, 2015 that is included herein in its entirety by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention pertains to gathering and collection systems and, more particularly, to collection system for tennis balls that includes a court drying feature. 
       BACKGROUND OF THE INVENTION 
       [0003]    Typically, a large portion of the time spent by players in a tennis game is expended retrieving tennis balls from various locations, both on and off the tennis court, where such balls roll dead after one of the players either misses striking the ball with his racket, or strikes it and fails to drive it to the proper area on the tennis court. Such necessity for constantly retrieving the tennis ball after it is knocked out-of-play is laborious and objectionable to many tennis players. This problem is exacerbated during and at the end of tennis practice sessions and clinics, where balls may be hit with no intention of having the ball returned by an opposing player. 
         [0004]    One excellent and relatively convenient way for a player to get needed practice is to utilize a ball throwing machine. The use of such machines eliminates the need for a second player or even a regulation size tennis court. Ball throwing machines may be installed in special lanes or practice alleys in which a player practices returning balls propelled by the ball machine. Ball throwing machines typically propel balls in rapid succession. Consequently, a large number of balls are needed to feed the machine in order to keep the machine in operation. Even if the ball thrower is constructed with a large capacity ball hopper, a large number of balls is required to avoid frequent interruptions of practice to pick up the spent balls and reload the ball hopper. Typically, many loose balls remain lying on the court, both distracting the player and providing possible sources of injury if the player steps on or trips over a loose ball. 
         [0005]    To avoid these disadvantages and meet the ball requirements for these automatic machines, ball retrieval machines have been developed to retrieve balls previously thrown and to transport them to the intake of the ball throwing machine. One such type of machine uses an air pressure source to propel balls through a tube from a collection point, such as at the bottom of a slope or incline constructed in the playing surface, to the intake of the ball throwing machine. 
         [0006]    Many solutions to the problem of retrieving scattered tennis balls have been suggested and implemented. One early solution was to hire a “ball boy” to actively retrieve tennis balls during a practice session or game. This solution added another person moving around the court and surrounding areas and proved distracting to many players. In addition, there was the expense of paying the “ball boy”. 
         [0007]    Various mechanical devices have been proposed for collecting tennis balls after a game, practice session, or clinic. One such device is the subject of U.S. Pat. No. 3,819,049 for BALL RETRIEVING APPARATUS, issued Jun. 25, 1974 to Francis Koerner et al. Koerner describes a vacuum cleaner-like device for sucking up and storing tennis balls from around the court. This again requires a person to move the device around the area having tennis balls to be retrieved and balls are collected on a one-at-at-time basis. 
         [0008]    Yet another method of collecting tennis balls from half of the tennis court consists of two ribs, one rib of which normally is located along each of two opposite edges of the court half. A drive system draws the ribs toward each other while conveying balls on the court surface, thereby to collect the balls from a limited area, and then to return the ribs to their original position. Controls for means are arranged to control the drive means. The controls are preferably actuatable by the player and from a position located within the limited ball-collecting area. Preferably at least one of the ribs is arranged to be angled or curved in the horizontal plane, such that the concave side of the rib faces the other rib. Even with such an apparatus, balls must be manually retrieved and transported. 
         [0009]    Yet another ball retrieval system found in the prior art is a system wherein the entire tennis court may be selectively tilted to force tennis balls to roll down the tiled tennis court to a collection area. An added advantage to this system is that the court may be disposed in a tilted position during a rain storm so water does not collect on the surface. Once rain stops, the tennis court is leveled and playing can be started quickly. 
         [0010]    Still another retrieval system has a ball retrieval arm mechanism extending from the base line to the tennis net on a tennis court. The arm may be moved along the net. During the retrieving process, the retrieving arm moves only one time during each passage in a transverse direction over one half of the tennis court. The retrieving arm continues its movement until it reaches one side edge of the tennis court. Ball receiving channels are provided along both sides of the tennis court, into one of which the balls are thrust by the retrieving arms and transported by one or more conveyor belts to one top end of the tennis court. The ball receiving channels have connections to a conveyor chute by which the balls are transported from the corners of the tennis court to a ball retriever placed in the middle of the top of the tennis court or to a ball retriever directly. 
         [0011]    It would, therefore, be advantageous to provide a system for quickly gathering dead tennis balls from a tennis court with little or no human intervention using air directed along the surface of the tennis court. It would be further advantageous to have features within the ball gathering system to dry the surface of a tennis court after rain or other deposition of moisture on the tennis court surface. 
       DISCUSSION OF THE RELATED ART 
       [0012]    Several attempts to provide apparatus to gather dead tennis balls from around a tennis court upon completion of a match or practice session are found in the prior art. For example, U.S. Pat. No. 3,203,696 for GAME APPARATUS issued Aug. 31, 1965 to Hermon R. Sawyer teaches a U-shaped conveyor system for collecting tennis balls from both halves of a tennis court. 
         [0013]    U.S. Pat. No. 3,819,049 for BALL RETRIEVING APPARATUS issued Jun. 25, 1974 to Frances Koerner et al. discloses a ball retrieving apparatus having a receptacle having a base provided with wheels, a storage chamber for balls to be picked up by suction through the mouth at the end of a hose connecting into the chamber, a screen floor for the chamber and a drawer below the chamber to collect debris from the collected balls and a suction or vacuum creating means in the receptacle, for use of the apparatus in picking up tennis balls, for example. 
         [0014]    U.S. Pat. No. 4,116,192 for TENNIS BALL RETRIEVER issued Sep. 26, 1978 to Jack C. Scott provides a tennis ball retriever and ball transporter for retrieving tennis balls from a collection point on a court surface and transporting the balls to a ball throwing machine. The machine comprises a pinwheel having sawtooth projections enclosed by a circular wall, with a tube extending through the wall in alignment with the movement of balls around the periphery of the wall, and an electric motor for rotating the pinwheel. As balls drop into open regions between the pinwheel projections and the wall, they are engaged by the projections and driven around the periphery of the wall into the open end of the tube. The opposite end of the tube extends to the ball throwing machine, which may be disposed on top of the retriever. 
         [0015]    U.S. Pat. No. 4,116,436 for BALL•COLLECTING APPARATUS issued Sep. 26, 1978 to Gunnar Bjorhn teaches an apparatus for collecting tennis balls on a tennis court half comprising two ribs, one rib of which is normally located along each of two opposite edges of the court half. Drive means are arranged to displace the ribs toward each other while conveying balls on the court surface, thereby to collect the balls in a limited area, and then to return the ribs to their normal position. Control means are arranged to control the drive means. The control means are preferably actuatable by the player from a position located within the limited ball-collecting area. 
         [0016]    U.S. Pat. No. 4,422,632 for TILTABLE TENNIS COURT issued Dec. 27, 1983 to Pierre Trottet discloses a panel mounted on a frame which in turn is mounted on a pivot disposed parallel to the longitudinal axis of the panel. Jacks connected to the frame permit tilting the panel which constitutes the tennis court. In this inclined position of the panel, rainwater will not accumulate on the court and the court can be reused as soon as the rain ceases to fall. 
         [0017]    U.S. Pat. No. 4,575,081 for TENNIS BALL RETRIEVING SYSTEM issued Mar. 11, 1986 to Peter A. Cavanagh provides a tennis ball recovery system for use in a full court utilizing an inelastic flexible damping screen hooked onto the back fence of the tennis court, which intercepts the driven ball and drops it onto a resilient apron that extends away from a collection trough. Within the trough there is located a conveyor that will move the balls toward the center of the trough and substantially central in the trough a conduit is provided with positive pressure to move the ball into a conduit and into a receptacle. 
         [0018]    U.S. Pat. No. 5,125,654 for TENNIS BALL RETRIEVING SYSTEM issued Jun. 30, 1992 to Wilbert Bruno teaches a retrieving system extending from the base line to the tennis net on a tennis court and can be moved along the net. During the retrieving process, the retrieving arm moves only one time during each passage in a transverse direction over one half of the tennis court. The retrieving arm continues its movement until it reaches one side edge of the tennis court. Ball receiving channels are provided along both sides of the tennis court, into one of which the balls are thrust by the retrieving arms and transported by conveyor belts to one top end of the tennis court. The ball receiving channels have connections to a conveyor chute by which the balls are transported from the corners of the tennis court to a ball retriever placed in the middle of the top of the tennis court or to a ball retriever directly. The retrieving arm is preferably guided only at one end thereof by a guide rail extending along the top of the tennis court. 
         [0019]    U.S. Pat. No. 6,050,625 for TABLE TENNIS BALL RETRIEVING AND DISPENSING SYSTEM issued Apr. 18, 2000 to Charles Richard Nisbet discloses a system for managing table tennis balls facilitates retrieval of stray balls, stores them and dispenses them conveniently to a player as required. The system has two main components: a ball retriever, a.k.a. the BallSnatcher, and a storage rack, a.k.a. the BallFeeder. The tubular retriever can hold a column of balls and is deployed in a hand-held manner in a vertical orientation from a standing position. The retriever is fitted at its bottom end with a ball trap including (a) a flexible coaxial constriction ring defining an expandable entry opening that when lowered over a stray ball captures and retains it in the retriever tube, and (b) a flexible coaxial guidance flange extending outwardly and downwardly to provide initial guidance in retrieving a stray ball. The tubular storage rack is mounted below the playing surface of a game table at a low angle; an open upper end is located along one side of the table where it can receive balls in an easy transfer from the retriever, while the opposite lower end is fitted with an end stop/dispenser, located at an end of the table convenient to a player, that retains the balls in the rack and dispenses them one at a time as required for play. The storage tube is sized to receive the open top end of the retriever for ball transfer; furthermore, the retriever can be inserted telescopically into the storage tube and left conveniently stored in this manner, ready to be easily pulled out for deployment 
         [0020]    U.S. Pat. No. 6,834,776 for TENNIS BALL RETRIEVING DEVICE issued Dec. 28, 2004 to Lynne Corvese shows a tennis ball retrieving apparatus wherein the tennis balls roll into the gutter portion of the device and an electronically controlled and powered paddle moves them into a ball conveyor system that dispenses the balls into a ball hopper. The gutter portion consists of three sections that are connected to each other by pins. A front ball stationary plate which does not rotate with the conveyor wheel prevents the tennis balls from falling out the front side of the conveyor wheel until the wheel rotates clockwise and brings the ball upward to an opening within the rear stationary plate where the ball is free to fall into the ball hopper chute and into the hopper. 
         [0021]    U.S. Pat. No. 7,114,877 for DRAINAGE SYSTEM FOR SPORTS FIELDS issued Oct. 3, 2006 to Dennis James Wilkerson teaches a system for draining bunkers on golf courses and other sports playing areas, and for draining landscaped areas. A receptacle is positioned below the surface for receiving drain water and for discharging the water through an outlet. A perforated pipe water collection system can be attached to the receptacle to direct water to the receptacle interior space. A receptacle cover is removable to permit access to the receptacle interior space. The cover is sufficiently strong to support the overlying weight of people and equipment, and can have apertures for permitting water entry while resisting entry of sand. 
         [0022]    Published United States Patent Application No. 2006/0068948 for TENNIS BALL COLLECTION, DISPENSING, AND TRANSPORT APPARATUS published Mar. 30, 2006 upon application by Lloyd Mendoza provides a tennis ball collection, dispensing, and transporting apparatus that includes a ball collection hopper for collecting tennis balls by a wheel-mounted sweeping apparatus. The ball collection hopper includes a forward facing opening for receiving tennis balls collected by the sweeping apparatus, for directing tennis balls over a one-way deflection panel and into the interior of the ball collection hopper. The deflection panel prevents collected tennis balls from accessing the sweeping apparatus and jamming the collection device during use, as well as retaining collected tennis balls during transport on and off the tennis court, as well as for securing the balls within the hopper when being dispensed 
         [0023]    Published United States Patent Application No. 2009/0249640 for DEVICE AND METHOD FOR REMOVING WETNESS published Oct. 8, 2009 upon application by Zbigniew Sufleta discloses a device for removing wetness includes a frame having a slot, a sheet of fluid absorbing material, at least a portion of which is located in the slot, wherein the sheet has a first end and a second end, a first handle coupled to the frame, and a second handle coupled to the first end. A method for removing wetness on a surface includes placing a sheet of fluid absorbing material on a wet surface, and pulling a first end of the sheet relative to a slot in a first direction so that part of the sheet moves through the slot to remove moisture from the sheet. 
         [0024]    None of the patents and published patent applications, taken singly, or in any combination are seen to teach or suggest the ball collection and court drying system for a tennis court or the like of the present invention. 
       SUMMARY OF THE INVENTION 
       [0025]    In accordance with the present invention there is provided a pneumatic ball gathering system that quickly clears and gathers tennis balls or similar items from a tennis court or other similar venue. One or a series of spaced-apart discharge nozzles are connected to a plenum with optional intervening valves. 
         [0026]    The plenum, one or more nozzles, and valves form a structure that is typically disposed underground when not in use and selectively raiseable when needed to clear balls or water from the tennis court. In one embodiment, the structure is located along one side edge of the tennis court. In a first alternate embodiment, the structure may be located under the net and be configured with one or more nozzles disposed to direct air in both directions away from the net. In a second alternate embodiment, the one or more nozzles are located along each side of the tennis court. Ball collection subsystems are located at each end of the tennis court. 
         [0027]    A collection trough is disposed either at an opposite side away from the air source or, in the first and second alternate embodiments, at each end of the tennis court. The collection trough may be formed with a slope to cause collated balls to roll downward therein. It is also possible to provide a mechanical conveyor system in the collection trough or troughs to move collected balls to a predetermined location. 
         [0028]    One or more vertical conveyors raise balls from the collection trough and discharge them into an appropriate container. 
         [0029]    The system may be used without activating any of the conveying components to direct streams of air across the tennis court to facilitate drying the court after rain. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    Various objects, features, and attendant advantages of the present invention will become more fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views, and wherein: 
           [0031]      FIG. 1A  is a top plan, schematic view of a portion of a tennis court with a simplified representation of a first embodiment of the ball gathering and court drying apparatus in accordance with the invention; 
           [0032]      FIG. 1B  is a top plan, schematic view of a portion of a tennis court with a simplified representation of a second embodiment of the ball gathering and court drying apparatus in accordance with the invention; 
           [0033]      FIG. 1C  is a top plan, schematic view of a portion of a tennis court with a simplified representation of a third embodiment of the ball gathering and court drying apparatus in accordance with the invention; 
           [0034]      FIG. 1D , is a top plan, schematic view of a belt conveyor; 
           [0035]      FIG. 1E  is a top plan, schematic view of a cleated belt conveyor; 
           [0036]      FIG. 1F  is an end, elevational schematic view of a ball barrier in a lowered, inoperative position; 
           [0037]      FIG. 1G  is an end, elevational schematic view of a ball barrier in a raised, operational position; 
           [0038]      FIG. 1H  is an end, elevational schematic view of an alternate embodiment of a ball barrier in a closed, inoperative position; 
           [0039]      FIG. 1I  is an end, elevational schematic view of an alternate embodiment of a ball barrier in an open, operational position; 
           [0040]      FIG. 2A  is a side elevational, cross-sectional, schematic view of a single nozzle, valve, and plenum in a lowered, non-operative position; 
           [0041]      FIG. 2B  is a side elevational, cross-sectional, schematic view of the single nozzle, valve, plenum of  FIG. 2A  in a raised, operational position; 
           [0042]      FIG. 3A  is a front elevational schematic view of a shutter type valve system with the; shutter closed; 
           [0043]      FIG. 3B  is a front elevational schematic view of a shutter type valve system of  FIG. 3A  with the shutter open; 
           [0044]      FIG. 3C  is a side elevational schematic view of the a shutter type valve system with the; shutter closed of  FIG. 3A ; 
           [0045]      FIG. 3D  is a side elevational schematic view of the a shutter type valve system with the; shutter open of  FIG. 3B ; 
           [0046]      FIG. 4  is a top plan, schematic view of a single nozzle attached to a rotation mechanism; 
           [0047]      FIG. 5A  is a simplified block schematic diagram of an air supply using an air compressor; 
           [0048]      FIG. 5B  is a simplified block schematic diagram of an air supply using a blower; 
           [0049]      FIG. 6  is a block schematic diagram of a controller suitable to use with the ball collection and courts drying system in accordance with the invention; and 
           [0050]      FIG. 7 , is a schematic representation of a possible embodiment of a control panel for use with the controller of  FIG. 6 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0051]    The present invention provides a ball gathering and court drying system for installation in a tennis court or the like. 
         [0052]    Referring first to  FIG. 1A , there is shown a top plan, schematic view of a portion of a tennis court with a simplified representation of a first embodiment of the ball gathering and court drying apparatus in accordance with the invention, generally at reference number  100 . 
         [0053]    A portion of a tennis court  102  having a net  104  supported by support posts  106  is shown schematically. Tennis court  102  has various markings  108  disposed on an upper surface thereof. None of tennis court  102 , net  104 , support posts  106 , or markings  108  form any part of the invention but are included to illustrate the intended operating environment for the ball gathering and court drying system in accordance with the invention. 
         [0054]    An air supply sub-system  120  is disposed along a right edge  110  of tennis court  102  and is substantially parallel to right edge  110 . As discussed in more detail hereinbelow, air supply system is designed for installation beneath the surface of tennis court  102 . 
         [0055]    Air supply sub-system  120  has an air supply plenum  122  disposed therealong. One or a series of nozzles  124  are spaced along and connected to plenum  122 . Plenum  122  is typically a cylindrical pipe having a relatively large diameter to minimize air pressure drop therealong. It will be recognized that a tapered plenum could be substituted to also control pressure drop. Consequently, the invention is not considered limited to any particular plenum cross-sectional geometry. The invention is intended to include rather any plenum cross-sectional geometry. 
         [0056]    Valves  126 , best seen in  FIG. 4  as well as  FIGS. 3A-3D  are inserted between plenum  122  and one or more nozzles  124 . 
         [0057]    Air, represented schematically by arrows  128  is forced out of one or more nozzles  124  in a direction parallel to the major axis, not specifically identified of one or more nozzles  124 . Air  128  pushes any balls  112  across tennis court  102 . A single ball  112   a  is shown schematically on tennis court  102  in a multi-image dashed pictogram depicting ball  112   a &#39;s movement across the tennis court  102  in the direction shown by arrow  114 . 
         [0058]    The air supply apparatus  120  is housed in a trough  130  of sufficient width and depth to contain plenum  122  and one or more nozzles  124  as well as a lift mechanism, best seen in  FIGS. 2A and 2B  and discussed in detail hereinbelow. 
         [0059]    A ball collection sub-system  140  is disposed at the left edge, not specifically identified, of tennis court  102 . Ball collection system  140  is aligned substantially parallel to air supply sub-system  120 . 
         [0060]    Ball collection sub-system  140  may be implemented as a simple trough  142  downwardly slopping toward a vertical ball conveyor system  150  or, in alternate embodiments, as a mechanical conveyor  146 , best seen in  FIG. 1D  that moves balls  112  toward vertical conveyor  150 . 
         [0061]    A vertical conveyor  150  at the terminus  142  of trough  140  and, when present, the terminus of horizontal conveyor  146 , best seem in  FIG. 1D , accepts balls  112  and lifts them upward to a discharge chute  152  where they are discharged into a ball container  154 . 
         [0062]    Referring now also to  FIG. 1B , there is shown a first alternate embodiment of the ball gathering and court drying apparatus in accordance with the invention, generally at reference number  200 . 
         [0063]    Ball gathering and court drying system  200  is similar to system  100  of  FIG. 1A  in most respects. 
         [0064]    A portion of a tennis court  102  having a net  104  supported by support posts  106  is shown schematically. For clarity, net  104  is shown as a solid line and posts  106  are not labeled in  FIG. 1B . Tennis court  102  has various markings  108  disposed on an upper surface thereof. None of tennis court  102 , net  104 , support posts  106 , or markings  108  form any part of the invention but are included to illustrate the intended operating environment for the ball gathering and court drying system  200  in accordance with the invention. 
         [0065]    An air supply sub-system  120  is disposed under net  104 . Like in system  100  of  FIG. 1A , air supply system  120  is designed for installation beneath the surface of tennis court  102 . 
         [0066]    Air supply sub-system  120  has an air supply plenum  122  disposed therealong. A first series of one or more nozzles  124   a  pointing in a first direction away from net  104  are interspersed with a second series of one or more nozzles  124   b  pointing in an opposite direction relative to the first series of one or more nozzles  124   a . One or more nozzles  124   a  and  124   b  are spaced along and connected to plenum  122 . Plenum  122  is typically a cylindrical pipe having a relatively large diameter to minimize air pressure drop therealong. 
         [0067]    Valves  126 , best seen in  FIG. 4  as well as  FIGS. 3A-3D , are inserted between plenum  122  and one or more nozzles  124  exemplified by nozzles  124   a ,  124   b.    
         [0068]    Air, represented schematically by arrows  128  is forced out of one or more nozzles  124   a ,  124   b  in directions perpendicular net  104 . Air  128  pushes any balls  112  along tennis court  102 . A single ball  112   a  is shown schematically on tennis court  102  in a multi-image dashed pictogram depicting ball  112   a &#39;s movement along tennis court  112   a  in the direction shown by arrow  114 . 
         [0069]    The air supply apparatus  120  is housed in a trough  130  of sufficient width and depth to contain plenum  120  and one or more nozzles  124   a ,  124   b  as well as a lift mechanism, best seen in  FIGS. 2A and 2B  and discussed in detail hereinbelow. 
         [0070]    A ball collection sub-system  140  is disposed at each end of tennis court  102 , only one shown in  FIG. 1B . Ball collection systems  140  are aligned substantially parallel to air supply sub-system  120 . 
         [0071]    Ball collection sub-systems  140  may be implemented as simple troughs  142  downwardly slopping toward a vertical ball conveyor system  150 . In alternate embodiments, a mechanical conveyor  142 , best seen in  FIG. 1D , may be used to move balls  112  toward vertical conveyor  150 . 
         [0072]    It will be recognized that the nozzle configuration as shown in  FIG. 1B  may be combined with the arrangement shown in  FIG. 1A  disposed parallel to the edge of tennis court  102 . Such an arrangement could be used to clear balls or water from two adjacent tennis courts, not shown. 
         [0073]    Referring now also to  FIG. 1C , there is shown a second alternate embodiment of the ball gathering and court drying apparatus in accordance with the invention, generally at reference number  300 . 
         [0074]    Ball gathering and court drying system  300  is similar in some respects to portions of both systems  100  and  200  of  FIGS. 1A and 1B , respectively. 
         [0075]    A portion of a tennis court  102  having a net  104  supported by support posts  106  is shown schematically. None of tennis court  102 , net  104 , or support posts  106 , form any part of the invention but are included to illustrate the intended operating environment for the ball gathering and court drying system  300  in accordance with the invention. 
         [0076]    An air supply sub-systems  120   a ,  120   b  are disposed along a respective left edge  110   a  and a right edge  110   b  of tennis court  102  and are substantially parallel to left and right edges  110   a ,  110   b . As discussed in more detail hereinbelow, air supply systems  120   a ,  12   b  are designed for installation beneath the surface of tennis court  102 . 
         [0077]    Each air supply sub-systems  120   a ,  120   b  has an air supply plenum  122   a ,  122   b  disposed therealong. A series of one or more nozzles  124  are spaced along and connected to air plenums  122   a ,  122   b . Plenums  122   a ,  122   b  are typically cylindrical pipes having a relatively large diameter to minimize air pressure drop therealong. It will be recognized that a tapered plenum could be substituted to also control pressure drop. Consequently, the invention is not considered limited to any particular plenum cross-sectional geometry. The invention is intended to include rather any plenum cross-sectional geometry. 
         [0078]    Valves  126 , best seen in  FIG. 4  as well as  FIGS. 3A-3D  are inserted between plenum  122  and one or more nozzles  124 . Also a shown in  FIG. 4 , one or more nozzles  124  are adapted to sweep from left to right in a plane substantially parallel to the upper surface, not specifically identified, of tennis court  102 . Typically, valves  126  are used to selectively supply air from respective air plenums  122   a ,  122   b  to valves  124 . By synchronizing the supply of air with the sweeping motion of the valve, balls may effectively be swept from tennis court  102  for collection by a ball collection sub-system  140  disposed at each end, neither specifically identified, of tennis court  102 , Sweeping motion and selective supply of air to the valves is controlled by control system  500 , best seen in  FIG. 6 . 
         [0079]    The air supply apparatuses  120   a ,  120   b  are housed in troughs  130   a ,  130   b , respectively, of sufficient width and depth to contain plenums  122   a ,  122   b  and nozzles  124  as well as a lift mechanism, best seen in  FIGS. 2A and 2B  and discussed in detail hereinbelow. In this embodiment, air may be alternately supplied to plenums  120   a ,  120   b , typically in short bursts. 
         [0080]    Air, represented schematically by arrows  128  is forced out of one or more nozzles  124  in a direction depending upon the particular rotated position of one or more nozzles  124  at any particular point in time. One or more nozzles  124  typically move between two extreme positions: (a)—a very small angle relative to the net, i.e. almost parallel to the net, typically 3-5°; and (b) almost perpendicular to the net, typically 45-85° with respect thereto. It will be recognized that other ranges of nozzle rotation may be chosen to meet a particular operating circumstance or environment and the invention is not considered limited to the specific range of rotation chosen for purposes of disclosure, 
         [0081]    Air  128  pushes any balls  112  down the tennis court  102  (i.e., away from the net towards ball collection sub stems  140  at each end of tennis court  102 ). The travel of tennis balls is anticipated to in zigzag patterns generally away from the net  104  and towards ball collection sub-systems  140  at each end of tennis court  102 . A single ball  112   a  is shown schematically on tennis court  102  in a multi-image dashed pictogram depicting ball  112   a &#39;s zigzag movement towards the end of tennis court  102  in the direction shown by arrows  114 . 
         [0082]    A ball collection sub-system  140  is disposed at the bottom edge, not specifically identified, of tennis court  102 . Ball collection system  140  is aligned substantially perpendicular to air supply sub-system  120 . 
         [0083]    Ball collection sub-system  140  may be implemented as a simple trough  142  downwardly slopping toward a vertical ball conveyor system  150  or, in alternate embodiments, as a mechanical conveyor  146 , best seen in  FIG. 1D  that moves balls  112  toward vertical conveyor  150 . It should be noted that in the embodiment of  FIG. 1C , balls  112  moving along trough  142  must pass under ball container  154 . As methods of elevating ball container  154  to provide clearance for balls  112  to pass beneath it are considered to be well known to those of skill in the art, such methods or mechanisms are not further discussed herein, 
         [0084]    A vertical conveyor  150  at the terminus  144  of trough  142  and, when present, the terminus of horizontal conveyor  146 , best seem in  FIG. 1C , accepts balls  112  and lifts them upward to a discharge chute  152  where they are discharged into a ball container  154 . 
         [0085]    Referring now also to  FIGS. 1D and 1E , there are shown top plan, schematic views of a belt conveyor and a cleated conveyor system, respectively. In alternate embodiments, ball collection sub-system  140  may include a conveyor  146 , to move balls  112  along in a direction indicated by arrows  156 . Such conveyors overcome possible problems with rubbish build up in trough  142 . In  FIG. 1D  a belt conveyor  146  is disposed in trough  142 . In  FIG. 1E , a cleated belt conveyor having cleats  148  disposed on the belt conveyor  146  to provide positive drive to balls  112  as they are moved along the horizontal conveyor in the direction shown by arrows  156 . It will be recognized that horizontal ball conveyor systems shown in  FIGS. 1D and 1E  are also applicable to the first embodiment of the ball collection and court drying system on  FIG. 1A . 
         [0086]    A ball barrier  184  or  186  is disposed proximate either an outside edge of trough  142  ( FIGS. 1F and 1G ) or within trough  142  ( FIGS. 1H and 1I ). 
         [0087]    A vertical conveyor  150  at the terminus  144  of trough  140  accepts balls  112  and lifts them upward to a discharge chute  152  where they are discharged into a ball container  154 . It is assumed that identical vertical conveyors  150  are disposed at each end of the tennis court. It will be recognized that a single vertical conveyor may be located at just one end of tennis court  102  and a ball conveying system, either above ground or beneath ground, neither shown, may be used to transfer collected balls  112  from a first trough  142  at a first end of tennis court  112  to the second trough  142  at an opposite end of tennis court  102 . 
         [0088]    The plenum  122 , nozzles  124 ,  124   a ,  124   b , and valves  126  form an air distribution system structure that is typically disposed underground when not in use and selectively elevatable when needed to clear balls or water from the tennis court. 
         [0089]    Referring now also to  FIGS. 1F and 1G , there are shown end elevational, schematic views of a first embodiment of a ball barrier  184  in a closed, inoperative position and an open, operative position, respectively. 
         [0090]    Ball barrier  184  is pivotally disposed over trough  142  ( FIG. 1G ) at a pivot or hinge  188 . When required to stop balls  112  from rolling beyond trough  142 , it may be rotated upwardly to a substantially vertical position as shown in  FIG. 1G . While no specific mechanism is show for moving ball barrier  184  from a closed to an open position, it is believed that such mechanisms are well known to those of skill in the art and as such, the mechanism in not further described or discussed herein. 
         [0091]    Referring now also to  FIGS. 1H and 1I , there are shown end elevational, schematic views of a second embodiment of a ball barrier  186  in a lowered, inoperative position and an raised, operative position, respectively. 
         [0092]    Ball barrier  186  is disposed within trough  142  ( FIG. 1H ) in a lowered, inoperative position. When required to stop balls  112  from rolling beyond trough  142 , it may be raised vertically to an operative position as shown in  FIG. 1I . While no specific mechanism is show for lifting ball barrier  186  from a lowered to a raised position, it is believed that such mechanisms are well known to those of skill in the art and as such, the mechanism in not further described or discussed herein. 
         [0093]    Referring now also to  FIGS. 2A and 2B , there are shown side elevational, cross-sectional, schematic views of a single nozzle  124 , valve,  126 , and plenum  122 , generally at reference number  200 . Valve  126  is connected to air plenum  122  by a plenum outlet pipe  132 . 
         [0094]      FIG. 2A  shows nozzle assembly  200  in a lowered, non-operational position while  FIG. 2B  shows nozzle assembly  200  in a raised, operational position. 
         [0095]    A trough  130  houses the plenum  122 , plenum outlet pipes  132 , valves  126 , and one or more nozzles  124  on a lifting mechanism  138 . A lifting cradle  136  is interposed between lifting mechanism  138  and plenum  122 . 
         [0096]    A cover  134  sized and configured to seal trough  130  when the air supply sub-system  120  is in a lowered, non-operational position. Cover  134  rests on cutaway areas in the top of trough  130  and is adapted to be substantially flush with the surface of tennis court  102 . 
         [0097]    As is seen in  FIG. 2B , air supply sub-system  120  is shown in an elevated, operational position. 
         [0098]    Lift mechanism  138  may be implemented in many ways known to those of skill in the art. A simple scissor jack type mechanism is shown for purposes of disclosure. While no power source is shown operably connected to lift mechanism  138 , it will be further recognized that an electric motor, a pneumatic motor, a hydraulic motor, or other types of actuators believed to be well known may be used to selectively actuate lift mechanism  138 . Consequently, the invention is not considered limited to the scissor jack type lift mechanism. Rather, the invention includes any and all suitable lift mechanisms. Likewise, the invention is not considered limited to any particular actuator operably connected to lift mechanism  138 . Rather the invention includes any and all suitable actuating mechanisms. 
         [0099]    Valves  126  may be implemented as electrically, pneumatically, or hydraulically actuated solenoid valves or as other types of valve. One possible valve construction is a movable shutter selectively placed in front of nozzles  124  to block or moderate the flow of air from one or more nozzles  124 . 
         [0100]    Valves  126  may be connected for individual actuation or, in alternate embodiments, valves may be grouped so that multiple valves are actuatable. 
         [0101]    Referring now also to  FIGS. 3A and 3B , there are shown front elevational schematic views of a representative shutter valve, generally at reference number  250 . 
         [0102]    In  FIG. 3A , a shutter  162  is shown in a closed position thereby blocking the air flow from a nozzle  124 . In  FIG. 3B , shutter  162  is shown in an open position whereby air may escape from nozzle  124 . 
         [0103]    A lip  160  along a major axis of trough cover  134  stabilizes shutter  162  while in a closed position as seen in  FIG. 3A . 
         [0104]    A lever  166  is operatively connected to shutter  162 . A pivot  168  in lever  166  allows shutter  162  to rotate thereabout in response to movement of lever  166 . 
         [0105]    A lever actuation band  170  extends along an upper surface of a base  176 , typically forming part of plenum lifting cradle  136 . A lever-engaging plate  172  is affixed to an upper surface of lever actuation band  170 , typically with screws  174  or other fasteners. It will be recognized that other attachment methods such as adhesive fastening, welding, or other type of fasteners may be substituted for screws  174  used for purposes of disclosure. 
         [0106]    Base  176 , supports a lever  166  rotatable on a pivot  168 . Lever  166  has a shutter disc  162  attached to a distal end thereof. Moving the proximal end of lever  168  by moving lever-engaging plate  172  affixed to an upper surface of lever actuation band  170  in a direction shown by arrow  178   a  causes shutter  162  to move from a closed position as seen in  FIG. 3A  to an open position as shown in  FIG. 3B . 
         [0107]    Shutter  162  is moved from a closed position to an open position by moving lever actuation band  170  and lever-engaging plate  172  in a direction shown by arrow  178   b.    
         [0108]    Lever actuation band  170  is operably connected to an actuator, not shown, that is disposed to reciprocally move lever actuating band  170  as shown by arrows  178   a  and  178   b . It will be recognized that actuators may be implements as bi-directional pneumatic or hydraulic cylinders; electrical solenoid arrangements, linear stepper motors, and other electrically, pneumatically, or hydraulically powered actuators. Such actuators are believed to be well known to those of skill in the art and, consequently, are not further described or discussed herein. 
         [0109]    In still other embodiments, the actuation system might be designed wherein shutters  162  are maintained in a closed position by one or more springs, not shown, and then opened by movement of shutter engaging plates  172  and shutter operating band  170 . An embodiment wherein shutter operating band moved in only a single direction and as shutter engaging plates  172  moved past, the spring(s), not shown, returned shutters  168  to their nominally closed position. Actuation of shutter operating band may be simplified in that a simple electric motor may be utilized to move shutter operating band  170 . 
         [0110]    Referring now also to  FIGS. 3C and 3D , there are shown side elevational views of the representative shutter valve of  FIGS. 3A and 3B , respectively. 
         [0111]    In all discussions heretofore, one or more nozzles  124  have been assumed to be fixed in a forward or rearward orientation. It is possible that one or more nozzles  124  be rotatable so as to reciprocally move across a certain arc, thereby facilitating “sweeping” balls  112  from the tennis court  102 . Referring now also to  FIG. 4 , there is shown a top plan, schematic view of a nozzle  124  moveable from side to side. 
         [0112]    Lawn sprinklers adapted for such reciprocal motion controlled by stops at each limit of the desired sprinkler head travel are believed to be well known. The implementation of such lawn sprinkler heads is believed to be transferable to one or more nozzles  124 . It will be recognized that many other possibilities for sweeping some or all of one or more nozzles  124  across controlled arcs and any suitable mechanism for so doing may be substituted. 
         [0113]    In  FIG. 4 , a nozzle  124  is attached to rotation mechanism  182  and is shown in an un-rotated, position pointing straight outward. Rotation mechanism  182  is operatively connected to a controller  502 , best seen in  FIG. 6 , via a connection  524 . A control signal, not shown, selectively applied by controller  502  via connection  524  causes nozzle  124  to move (i.e., sweep) between positions indicated by nozzles  124   a  and  124   b  shown in broken lines. While an angle of approximately plus or minus 30° from the straight forward position is shown in  FIG. 4 , it will be recognized that many other sweep angles may be chosen to meet a particular operating requirement. Consequently, the invention is not considered limited to the approximately plus or minus 30° sweep range chosen for purposes of disclosure. Rather, the invention is intended to cover any angular sweep range. 
         [0114]    Rotation mechanism  182  is connected to a valve via a flexible connection  180 . Valve  126  is shown with a connection  518  that provides a control signal from controller  502 . While an electrically actuated valve is shown for purposes of disclosure, as discussed hereinabove, a pneumatically or hydraulically controlled and/or actuated valve may be substituted. 
         [0115]    Consequently, the invention is not considered limited to the implementation chosen for purposes of disclosure but rather it is intended to include any and all suitable nozzle sweeping mechanisms. 
         [0116]    Sweeping the nozzles may be useful for dislodging tennis balls close to air supply sub-system  120  but between nozzles. Sweeping the one or more nozzles may also be useful when the ball collection and court drying system is used in court drying only mode as discussed in more detail hereinbelow. 
         [0117]    Referring now also to  FIG. 6 , there is shown a greatly simplified system block diagram of the ball collection and tennis court drying system in accordance with the invention, generally at reference number  500 . 
         [0118]    Heretofore the air source for operating the ball collection and court drying system has not been discussed. In one embodiment, a large multi-stage centrifugal compressor may be used to supply large volumes of relatively low pressure air to plenum  120 . With this type of air flow, the system could be operated continuously for several minutes to clear or dry the court. 
         [0119]    In an alternate embodiment, the ball collection and court drying system could be operated in a “single shot” mode. In this type of operation, a large reservoir of relatively high pressure compressed air is created by one or more relatively small compressors. Once the reservoir is at an intended pressure, the air may be released to the one or more nozzles as a short blast at high pressure to clear and/or dry the court. In this embodiment, a large air reservoir is disposed away from plenum  122 . It is possible to use the plenum  122  as part of the air reservoir to reduce the size of the external tank (i.e., reservoir). In alternate embodiments, it is possible to increase the size of plenum  122  so as to completely eliminate the need for an external tank altogether. 
         [0120]    Referring now also to  FIG. 5A  there is shown a simplified system block diagram of a compressor-based air supply system, generally at reference number  400 . 
         [0121]    An air compressor  402  has an output connected to an output pipe  406  that is, in turn, connected to an air reservoir tank  404 . A control signal  508  generated by master controller  502  is supplied to compressor  402 . It will be recognized that compressor  402  requires a power source. An appropriate power source is assumed to be present and forms no part of the invention. 
         [0122]    A pressure regulator  418  is generally inserted inline in output pipe  406 . Typically, pressure regulator  418  will have an operative connection, not shown, to compressor  402 . 
         [0123]    An optional air pressure gauge  408  is connected to tank  404 . In addition, a safety relief valve  410  is also connected to tank  404 . 
         [0124]    An output pipe  412  conducts air from air reservoir tank  404  to an optional “dump” valve  414 . Dump valve  414  is selectively actuated in response to a signal received from master controller  502 . 
         [0125]    The air output from dump valve  414  is connected to air plenum  122 . 
         [0126]    Referring now also to  FIG. 5B , there is shown a simplified system block diagram of a blower-based air supply system, generally at reference number  420 . The compressor  402  of  FIG. 5A  is replaced by a blower  422  in this embodiment. The need for a reservoir tank  404 , a pressure gauge  406 , and a pressure relief valve  410  is completely eliminated and the output of blower  422  is connected directly to air plenum  122  by an output duct  424 . 
         [0127]    A control signal  508  generated by master controller  502  is supplied to blower  422 . It will be recognized that blower  422  requires a power source. An appropriate power source is assumed to be present and forms no part of the invention. 
         [0128]    Referring now also to  FIG. 6 , there is shown a simplified system block diagram of a control system, generally at reference number  500 . The entire ball collection and court drying system is operated by control system  500 . 
         [0129]    A master controller  502  is typically controlled by one or more control panels  504 . It will be recognized that many possible configurations for control panel  504  interacting with master controller  502  are possible. For example, full control may be exercised from a control panel, not specifically identified, located in an office or other administrative facility with a control panel, not specifically identified, having only partial control and disposed near each tennis court. For purposes of disclosure, a single control panel  504  is shown schematically connected to master controller  502 . Details of a typical control panel are shown in  FIG. 7 . 
         [0130]    A control line  506  operatively connects compressor or blower  402  to master controller  502 . A control line  508  operatively connects lift mechanism  138  to master controller  502 . A control line  510  connects ball return conveyor  146  to master controller  502 . A control line  512  connects vertical conveyor  150  to master controller  502 . 
         [0131]    A control line  514  connects master controller  502  to a nozzle valve controller/sequencer sub-system  516 . Nozzle valve controller/sequencer is anticipated to be a programmable unit that defines the way air is applied to one or more nozzles  124  by controlling groups of valves  126 . One function of nozzle valve controller/sequencer  516  is to control whether the full tennis court  102  or only a portion thereof is cleared. The court portion typically is one half the tennis court  102 . Various patterns may be pre-programmed to control the sequence of air application to one or more nozzles  124  or groups of one or more nozzles  124 . 
         [0132]    An output bus  518  connects nozzle valve controller/sequencer  516  to individual valves  126 , each valve  126  or preselected group of valves  126  having a conductor, not specifically identified, in output bus  518 . 
         [0133]    An output connector  520  connects master controller  502  to a swivel controller/sequencer  522  that controls the swivel mechanisms  182  associated with particular one or more nozzles  124 . Like nozzle valve controller/sequencer  516 , a swivel controller/sequencer  522  is anticipated to be a programmable unit that defines movement of individual or possible groups of nozzles  124 . Swivel controller/sequencer  522  controls the sweep range by setting left and right swivel stop points, not specifically identified, for the angular movement of one or more nozzles  124 . 
         [0134]    An output bus  524  connects swivel controller/sequencer  522  to individual, rotation mechansims  182  or preselected groups of rotation mechansims  182  having a conductor, not specifically identified, in output bus  524 . 
         [0135]    Master controller  502  may incorporate an audible/visible alert  528  to notify persons in the vicinity of tennis court  102  when the ball gathering and court drying system is about to be activated. Such warning is appreciated when an implementation using a release of compressed air is in use as the sound of the air release may be relatively loud. 
         [0136]    Referring now also to  FIG. 7 , there is shown a schematic representation of a possible embodiment of a control panel  504 . Control panel  504  has a master switch  530 , represented in  FIG. 7  as a key switch. 
         [0137]    A blower (or compressor in alternate embodiments) on-off switch  532  has indicator lamp  534  adjacent thereto. An additional indicator lamp  536  illuminates when a compressed pressure in reservoir tank  404  is sufficient to perform a single shot air release. 
         [0138]    Another switch  538  turns horizontal ball conveyor  146  on and off. An indicator lamp  538  indicates when horizontal ball conveyor  146  is operating. 
         [0139]    A switch  542  raises and lowers air supply sub-system  120 . An indicator lamp  544  illuminates when air supply sub-system  120  is raised. 
         [0140]    A court selection switch  550  allows selection of left half  552 , full court  555 , and right court  554  operation 
         [0141]    A switch  556  “arms” the nozzles. An indicator lamp  158  illuminates when the nozzles are armed to allow a single shot release of air to be triggered. The arming operation could include moving shutter  162  from the front of one or more nozzles or any other preliminary operations necessary for a single shot air blast mode of operation. 
         [0142]    A switch  560  starts nozzle sweeping. An indicator lamp  562  illuminates when nozzles are sweeping. 
         [0143]    A Fire button  564  initiates a one shot air release. Prior to the actual release, an audible/visible alert may be actuated for several seconds to alert persons near the court to be cleared or dried that a loud sound is imminent. After a several second delay, dump valve  414  is opened. 
         [0144]    While conventional toggle switches have been chosen for purposes of disclosure, many alternatives are possible for control panel  504 . For example, a touch screen display, not shown, may be used to implement the illustrated functions. 
         [0145]    It will be recognized that alterations may be made to control panel  504  to adapt it for controlling a blower-base, continuous air release system. Such changes are considered obvious to persons of skill in the art and are not discussed in further detail herein. 
         [0146]    It will be further recognized that semi-automatic or fully automatic control systems may be implemented to allow provide a “single button” to cycle the ball collection and court drying system by providing sequences operation of each component of the system at an appropriate time. 
         [0147]    Since other modifications and changes varied to fit particular operating requirements and environments will be apparent to those skilled in the art, the invention is not considered limited to the example chosen for purposes of disclosure, and covers all changes and modifications which do not constitute departures from the true spirit and scope of this invention. 
         [0148]    Having thus described the invention, what is desired to be protected by Letters Patent is presented in the subsequently appended claims.