Abstract:
An amusement device, comprising two cooperating units. Each unit is equipped with a net for catching an incoming airborne ball, and a launcher for launching the ball, once caught. The two devices, if properly programmed, can juggle two, or more, balls.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to amusement devices and more specifically, to an automated device suitable for juggling table tennis balls.  
         BACKGROUND OF THE INVENTION  
         [0002]    Numerous devices exist for pitching baseballs, tennis balls, table tennis balls, and the like to a person waiting to bat or catch the balls. These devices satisfactorily serve their primary purpose, namely, sports training, but leave remaining a need for an amusement device which is capable of completing a loop or cycle of ball travel in the absence of direct user participation.  
         SUMMARY OF THE INVENTION  
         [0003]    The present invention provides a device having a station from which a ball (or other substantially hollow projectile) is launched; a basket (or other suitable diverter) connected to the station and operable to catch an airborne ball; and a gun (or other suitable launcher) connected to the station and operable to shoot a ball caught by the basket. The device facilitates a variety of amusing endeavors, many of which involve movement of a ball through a closed circuit which includes an airborne portion.  
           [0004]    In a first application involving the present invention, a single device is used to facilitate an interactive game of catch. In particular, a person attempts to throw a ball into the basket on the device. If the attempt is successful, then the gun on the device shoots the ball back toward the person. If the attempt is unsuccessful, then the person must retrieve the ball and try again. The device may include an optional sensor for sensing when the ball is in position and signalling the gun to shoot accordingly, or the device may simply cause the gun to shoot intermittently regardless of the presence or absence of the ball.  
           [0005]    In another application involving the present invention, a single device is used to play a game of catch with itself. In particular, the ball is loaded into the basket and subsequently shot either straight up in the air or toward a suitable rebound surface. The position of the device and/or the orientation of the gun may be adjusted so that the ball strikes the rebound surface and returns to the basket. The rebound surface may simply be a vertical wall forming part of a building or it may be an inclined surface (or any of several such surfaces) on a relatively smaller object, such as a paperweight or a desk clock. The ball may also strike more than one surface before returning to the basket. With an embodiment having the gun and the basket offset from one another, the present invention may be used to juggle multiple balls in cascading fashion. Another option involving a single device is to dispose the device at a first location and aim the gun at a second location which is connected to the first location by means of a ball returning track.  
           [0006]    In an additional application involving the present invention, two of the devices are used to automatically play catch with one another. The gun on the left-hand device shoots the ball into the basket on the right-hand device, and then the gun on the right-hand device shoots the ball into the basket on the left-hand device. The relative positions of the devices may be established by trial and error, mathematical computation, a properly scaled measuring device, computer simulation, etc. With the introduction of multiple balls, devices with offset guns and baskets may be used to juggle in alternating or cross-over fashion.  
           [0007]    In one mode of operation, a remote, hand-held trigger may be provided for each station, so that an operator can feel like he is juggling by controlling the firing sequence (LED&#39;s could be provided to “countdown” each launch time). In another mode of operation, each gun may be programmed to automatically shoot at a certain time (including on the hour and every fifteen minutes thereafter to provide a time keeping function, for example), or to shoot only after a sensor indicates the presence of the ball, or to shoot in response to a user generated signal. A potentiometer or other suitable means could be provided to adjust the automatic firing sequence of a respective gun, particularly when attempting to simulate juggling or some other critical firing sequence. Another possible variation is to facilitate adjustment to the strength and/or inclination of the guns.  
           [0008]    In yet another application involving the present invention, at least the gun portion of a device is mounted on a base, and at least the basket portion of a device is mounted on a vehicle. The gun on the base shoots the ball into the basket on the vehicle. The position of the vehicle relative to the trajectory of the ball may be controlled in several different ways.  
           [0009]    In one mode of operation, the vehicle occupies a “docked” or known position relative to the base. When a “start” signal is received, the vehicle departs toward an intercept position, and the gun on the base shoots the ball to arrive at the intercept position no sooner than the basket on the vehicle. Depending on the parameters involved and/or the desired effect, the gun may shoot before the vehicle departs, while the vehicle is moving, or after the vehicle has reached its destination.  
           [0010]    Rather than shooting at the end of an appropriate time delay, the gun may alternatively shoot in response to a user generated signal, or in response to a signal generated by the vehicle. In one example of the latter scenario, for example, a sensor is be disposed along the path of the vehicle to generate a signal upon the arrival and/or passage of the vehicle. Multiple sensors may be used to generate additional actions, such as a preliminary “Ready, Aim, Fire” audio sequence, and/or to fire multiple balls where, for example, the vehicle is a train pulling multiple cars with baskets.  
           [0011]    The vehicle may move in a variety of ways, including along a track; back and forth in a straight line across a floor surface; or any of several available routes across a floor surface. The vehicle may occupy and/or depart from a variety of known positions relative to the base, including in contact with the base; or a known location on a track which could be connected to the base or be spaced apart from the base. The vehicle may return the ball to the base by travelling back to the base with the ball on board, or by shooting the ball back to the base or by delivering the ball to another device on either a base or a vehicle.  
           [0012]    In another mode of operation, a controller knows and/or controls the trajectory of the ball and the position of the vehicle. The controller may move the vehicle to intercept the trajectory of the ball and/or may adjust the gun to alter the trajectory of the ball so that it terminates at the location of the vehicle.  
           [0013]    In yet another mode of operation, a person may control the position of the vehicle and/or the trajectory of the ball. In a game, for example, a person may be required to get the vehicle to a designated position in time to catch the ball. A defender may have the task of attempting to impede the person&#39;s progress by attacking and/or obstructing the path of the vehicle (by using another vehicle, laying down mines, etc.).  
           [0014]    In still another application involving the present invention, a device is mounted on a first vehicle, and a device is mounted on a second vehicle. In a first type of game involving the vehicles, they play catch with one another by shooting the ball back and forth, and/or they both attempt to catch a single ball fired from a base. In another type of game game, one group or team of vehicles attempts to move the ball down a field while another team attempts to defend (in a manner similar to Ultimate Frisbee). When a sensor indicates the presence of the ball, that vehicle&#39;s motor ability is impaired, and that vehicle&#39;s gun must be fired within a predetermined time or it fires automatically. When the ball is “dropped” the other team takes possession.  
           [0015]    In an automated game of catch, two such vehicles may be mounted on a closed circuit track at positions approximately diametrically opposed from one another. A controller may use sensors to monitor the relative positions of the vehicles and fire the guns at appropriate times. In the alternative (which eliminates the need for sensors), two of the devices may simply be mounted on a rotating member at angularly displaced locations. Additional aspects of the present invention may become apparent from the more detailed description that follows. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    [0016]FIG. 1 illustrates one form of the invention, and a flow chart illustrating a sequence of steps executed by LOGIC 108. The LOGIC need not be digital.  
         [0017]    FIGS.  2 A- 2 C illustrate a sequence of events undertaken by the apparatus of FIG. 1.  
         [0018]    [0018]FIG. 3 illustrates one form of the invention.  
         [0019]    FIGS.  4 - 6  illustrate a sequence of events undertaken by one form of the invention.  
         [0020]    [0020]FIGS. 7 and 8 illustrate a sequence of events undertaken by one form of the invention.  
         [0021]    [0021]FIGS. 9 and 10 illustrate a sequence of events undertaken by one form of the invention.  
         [0022]    [0022]FIGS. 11A, 11B,  12 A, and  12 B illustrate a sequence of events undertaken by one form of the invention.  
         [0023]    [0023]FIG. 13 illustrates a sequence of events undertaken by one form of the invention.  
         [0024]    [0024]FIGS. 14A and 14B illustrate one form of the invention.  
         [0025]    [0025]FIG. 15 is an enlarged view of part of FIG. 14A.  
         [0026]    [0026]FIG. 16 illustrates one form of the invention.  
         [0027]    [0027]FIGS. 17A, 17B,  18 A, and  18 B illustrate a sequence of events undertaken by one form of the invention.  
         [0028]    [0028]FIG. 19 illustrates one form of the invention, wherein sensors  1  and  2  detect position of a vehicle along a track  520 , and issue signals to a computer so indicating.  
         [0029]    [0029]FIG. 19A illustrates a sensor  535  supported by a mast  536 .  
         [0030]    [0030]FIGS. 20 and 21 illustrate a sensor  530  for detecting position of a vehicle  200 A on track  539 .  
         [0031]    [0031]FIG. 22 illustrates one form of the invention.  
         [0032]    [0032]FIG. 23 illustrates a toy train  200 A carrying two ball-catching baskets  580 .  
         [0033]    [0033]FIG. 24A illustrates a prior-art servomechanism  600 .  
         [0034]    [0034]FIG. 24B illustrates a linkage driven by the servomechanism  600 , which rotates cannon  620  in a horizontal plane.  
         [0035]    [0035]FIG. 24C illustrates a linkage driven by the servomechanism, which rotates cannon  620  in a vertical plane.  
         [0036]    [0036]FIGS. 24D and 24E illustrate one form of the invention.  
         [0037]    [0037]FIG. 25 illustrates one form of the invention, wherein no stick-shaped objects are present, for safety.  
         [0038]    [0038]FIGS. 26 and 17 illustrate other forms of the invention.  
         [0039]    [0039]FIG. 28 illustrates one form of the invention, and a block diagram illustrating electronic, or mechanical, apparatus for controlling firing of the cannon  400 .  
         [0040]    [0040]FIG. 29 is a high-level block diagram, illustrating control of solenoid  425 .  
         [0041]    [0041]FIGS. 30A, 30B, and  30 C illustrate circuits for triggering the solenoid  425  in FIG. 29, together with timing diagrams.  
         [0042]    [0042]FIGS. 31 and 33 illustrate control circuitry.  
         [0043]    [0043]FIG. 32 illustrates one approach to adjusting power delivered to the solenoid  425 .  
         [0044]    [0044]FIGS. 34A and 34B illustrate a charge-discharge sequence for capacitor C 1 .  
         [0045]    [0045]FIG. 35 illustrates a sensor for detecting an incoming ball.  
         [0046]    [0046]FIGS. 36 and 37 illustrate the sensor of FIG. 35 used as a launcher for a ball B.  
         [0047]    [0047]FIGS. 38 and 40 illustrate one form of the invention.  
         [0048]    [0048]FIG. 39 illustrates one form of the invention.  
         [0049]    [0049]FIG. 41 illustrates juggling by two units.  
         [0050]    [0050]FIG. 42 illustrates a timing sequence which allows two units, such as unit  100  in FIG. 38, to juggle multiple balls.  
         [0051]    [0051]FIG. 43 illustrates juggling by a single unit.  
         [0052]    [0052]FIG. 44 illustrates one form of the invention.  
         [0053]    [0053]FIG. 45 is a flow chart illustrating a sequence of steps undertaken by one form of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0054]    [0054]FIG. 1 illustrates a launcher  100  which launches a table tennis ball B. The ball B is held within a basket  105 , which contains perforations  106 , which reduce aerodynamic drag and back-pressure upon the ball during launching. Logic 108 controls a solenoid  25 , whose plunger, or hammer,  115  strikes the ball B upon actuation of the solenoid  108 . As indicated by arrow  118 , the logic  108  performs three functions.  
         [0055]    In block  125 , the logic  108  inquires whether sensor  120  detects that the ball is present within the basket  105 . If not, the NO branch is taken, and the logic idles in loop  126  until the sensor  120  detects a ball.  
         [0056]    When a ball is detected, the logic exits loop  126 , and reaches block  130 , which imposes a delay. As will be explained below, the delay is adjustable, and can range from a length of zero to a few dozens of seconds in duration. Next, block  135  is reached, wherein the solenoid  110  is energized, thereby ejecting the ball from the basket.  
         [0057]    The operation just described allows a pair of launchers  100  to play the game of “catch” as shown in FIG. 2. In FIG. 2A, launcher  100 A launches the ball B to launcher  100 B, which catches ball B in its basket  105 B. The sensor  120  (not shown) in launcher  100 B detects the presence of the ball. In FIG. 2B, the delay of block  130  in FIG. 1 is imposed. In FIG. 2C, launcher  100 B returns ball B to launcher  10 A, and the sequence of FIGS. 2A, 2B, and  2 C continues.  
         [0058]    Details concerning the construction of launcher  100  in FIG. 1 can be found in U.S. Pat. No. 5,100,103, issued on Mar. 31, 1992, and filed on Feb. 20, 1990, Ser. No. 482,035, and in U.S. Pat. No. 5,125,668, issued Jun. 30, 1992, filed on Apr. 24, 1990, Ser. No. 513,928. The inventor in both of these patents is Gregory A. Welte, a co-inventor herein. Both of these patents are hereby incorporated by reference in their entireties, including definitions stated therein.  
         [0059]    The logic 108 can be implemented in either digital or analog format. FIG. 3, which contains a partial, annotated, copy of FIG. 4 of the ′103 patent identified above, illustrates analog circuitry which can implement the logic 108 . The overall action is to trigger the ONE SHOT into driving Darlington 52 temporarily into conduction, to apply a pulse to solenoid  25 .  
         [0060]    In executing this action, sensor  120  in FIG. 1 closes switch  40  in FIG. 3 momentarily, when the ball B is detected. Switch  40  can take the form of a transistor. Upon closure, capacitor  42  in FIG. 3 charges almost immediately. When switch  40  is opened, capacitor  42  begins to discharge through resistor  44 . This discharge causes voltage Vcap to drop.  
         [0061]    When Vcap falls below the voltage on line  48 , comparator  46  trips, triggering the ONE SHOT, which issues pulse  51 . The time interval between release of switch  40  and the tripping of comparator  46  corresponds to the delay of block  130  in FIG. 1. Pulse  51  momentarily turns on Darlington 52, causing the hammer H of solenoid  25  to strike the ball  29 .  
         [0062]    The launcher  100  in FIG. 3 is equipped with two knobs  140  and  145 . Knob  140  controls the power applied to the solenoid  25 , and thus controls the force with which the hammer H strikes the ball, thereby controlling the distance which the ball  29  travels. One approach to controlling this power is to adjust the duration of pulse  51 . This adjustment can be made by adjusting the RC time constant of the appropriate resistor and capacitor used by the ONE SHOT, as indicated by arrow  150 . This adjustment allows the distance between launchers  100 A and  100 B in FIG. 2 to be changed. Another approach is to adjust the voltage applied to the solenoid  25 . FIG. 2 shows ten volts being applied; that voltage can be changed.  
         [0063]    Still another approach is independent of knob  140 . The speed with which the hammer H of the solenoid strikes the ball  29  in FIG. 3 depends upon how far the hammer H is withdrawn from the solenoid at the time current is applied to the solenoid. If the hammer H is held at a slightly withdrawn position, the final speed will be small, compared with that occurring if the hammer H is withdrawn farther. A set screw SET can adjust the resting position of the hammer H.  
         [0064]    Knob  145  in FIG. 3 controls the length of the delay of block  130  in FIG. 1, by changing the RC time constant of resistor  44  and capacitor  42  in FIG. 3, as indicated by arrow  155 . Control over this delay will be important in other embodiments, discussed later.  
         [0065]    In FIG. 3, the basket  105  can pivot about pivot P, thereby changing angle A, to thereby allow an additional adjustment in the range of the launcher  100 .  
         [0066]    In FIG. 4, a motorized miniature truck  200  carries a basket  205 . The truck  200  follows a path  210 , which can represent a guide rail which constrains the truck, or can represent the path taken by the truck because of either the truck&#39;s design or programming. The truck moves from the FIRST position to the SECOND position. Then, when the truck reaches the THIRD position in FIG. 5, the launcher  100 , of the type shown in FIG. 1, launches a ball B. If the launching is timed properly, the ball B will be captured by the basket  205 , as indicated in the FOURTH position.  
         [0067]    The truck  200  continues along path  210 , as indicated by the FIFTH position in FIG. 6, carrying the ball, and reaches the SIXTH position. The player (not shown) removes the ball B, loads it into the launcher  100 , and the truck continues to the FIRST position shown in FIG. 1.  
         [0068]    During the truck&#39;s travel from the FIRST position to the SIXTH position, the firing of the launcher  100  can be undertaken in several ways. In one approach, the time delay is appropriately adjusted by knob  145  in FIG. 3. Switch  40  in FIG. 3 is momentarily closed when the truck is located at the FIRST position in FIG. 4. The truck proceeds to the SECOND position, and the launcher  100  launches the ball B when the truck is at the THIRD position in FIG. 5, when the time delay expires, thereby assuring that the basket  205  will capture the ball as indicated in the FOURTH position.  
         [0069]    In another approach, the firing of the launcher is under direct control of the player. For example, the RC time constant of resistor  44  and capacitor  42  in FIG. 3 can be very small, so that launch of the ball B occurs immediately upon closure of switch  40 . The player controls switch  40 , and causes launch when the truck is located at the THIRD position in FIG. 5.  
         [0070]    In a third approach, a computer controls the launch, as discussed later.  
         [0071]    In a fourth approach, a sensor  207  in FIG. 5 detects the presence of the truck  200 , and issues a signal on line  73 . Line  73  connects to diode  141  in FIG. 3, and triggers the ONE SHOT.  
         [0072]    [0072]FIG. 7 illustrates a variation of the apparatus just described. The truck  200  is equipped with a launcher  100 D. After the truck reaches the position shown in FIG. 7A, the launcher  100  fires. A net  250  within the truck  100  catches the ball B, and feeds the ball B to the truck&#39;s launcher  100 D. The net  250  can take the form of basket  105  in FIG. 3, which is part of launcher  100 .  
         [0073]    In FIG. 7B, after a delay, the truck&#39;s launcher  100 D launches the ball B to a stationary launcher  100 C, which catches the ball B, as indicated in FIG. 8A. Then, after another delay, stationary launcher  100 C launches the ball B to the first launcher  100 , as indicated in FIG. 8B. If the delays of the proper lengths are selected, the sequence just described will continue.  
         [0074]    [0074]FIGS. 17 and 18 illustrate a variation. In FIG. 17A, truck  200  drives along path  520 . In FIG. 17B, launcher  100 F launches a ball B into the truck. In FIG. 18A, the truck  200  continues its travel. In FIG. 18B, the truck  200  launches the ball B to the launcher  100 F, and the process continues.  
         [0075]    In another embodiment, shown in the sequence of FIG. 9, truck  200  carries a mobile launcher  100 E, and drives away from a stationary launcher  100 A. The latter launchers ball B, which is caught by the mobile launcher  100 E. The mobile launcher  100 E then launches the ball B to the stationary launcher  100 A. The appeal of the apparatus of FIG. 9 to a player is that care must be taken to set the delays and power settings of both launchers properly.  
         [0076]    As shown in FIG. 10, the truck  200  need not follow a straight-line path, but may follow a serpentine path. The truck may be programmable as to path. The patents incorporated above describe programming approaches. Also, programmable vehicles are known in the art.  
         [0077]    [0077]FIG. 11A illustrates another type of launcher  300 . A barrel  302  contains a launching station  305 , and utilizes the principles of FIGS. 1 and 3 to launch a ball. A magazine of balls  307  may be provided, which holds a supply of balls. A net  315  catches incoming balls, and delivers them to the magazine.  
         [0078]    In operation, the launcher  300  can launch a ball toward a wall  310 , as indicated in FIG. 11B. The wall deflects the ball, as in FIG. 12A, and the net  315  catches the deflected ball, as in FIG. 12B. This process repeats.  
         [0079]    In FIG. 13, a wall is not used, but a human (not shown) catches and returns the ball B.  
         [0080]    [0080]FIG. 14 illustrates construction details of one type of launcher. In FIG. 14A, a barrel  400  contains a launching station  405 . Balls are delivered to the launching station  405  by a funnel  410 , through aperture  412 . A sleeve-type net  415  delivers balls to the funnel  410 . A goal-type net  420  catches incoming balls, and delivers them to the sleeve-net  415 . A solenoid  425  launches the ball (not shown).  
         [0081]    A base  430  supports a mast  435 , which carries a U-shaped bracket, which supports the barrel  400 . FIG. 14B illustrates the apparatus in assembled form.  
         [0082]    A significant feature of FIG. 14B is that the funnel  410  does not contact the barrel  400 . Further, the components are configured such that, when the barrel  400  is rotated about either axis  450  or axis  460 , the aperture  412  remains in a position which enables funnel  410  to deliver balls to the launching station.  
         [0083]    This relative fixity of position of funnel  410 , with respect to aperture  412 , allows the barrel  400  to be positioned without moving goal-net  420 . This can be important when two launchers are used in the game shown in FIG. 2. First, the goal-net  420  of the second launcher is positioned, and the first launcher  400  is adjusted to shoot a ball into that net. When this adjustment is accomplished, the second launcher is then adjusted to fire a ball into the goal-net of the first launcher.  
         [0084]    However, if the adjustment of the second launcher required movement of its goal-net, then the first launcher would require additional adjustment, in order to strike the newly positioned goal-net of the second launcher. The separation between barrel  400  and funnel  410  in FIG. 14 eliminates this problem.  
         [0085]    [0085]FIG. 15 is a cross-sectional view of part of FIG. 14, showing barrel  400 , launching station  405 , solenoid  425 , ball B, and funnel  410 .  
         [0086]    [0086]FIG. 16 is a cross-sectional view of an apparatus of the type shown in FIG. 14, but with some modifications. The sleevenet  415  of FIG. 14A has been eliminated. FIG. 16 shows that the axis of rotation  460  of barrel  400  is concentric with funnel  410 . Barrel  400  can also rotate about pivot P, as indicated by arrows  470 . A sensor  500  detects the presence of ball B, and delivers a signal so indicating to control  510 , which is discussed later.  
         [0087]    Apparatus which controls the events described above is shown in FIGS.  19 - 21 . FIG. 19 is a top view of FIG. 7A, with components added. Two sensors, SENSOR  1  and SENSOR  2 , are shown. Such sensors are described in the incorporated patents. These sensors detect the presence of the truck  200  in FIG. 17, and issue signals which will be called “vehicle-present” signals.  
         [0088]    A computer is indicated as a receiver of the “vehicle present” signals. When a vehicle-present signal is received from SENSOR  1 , the computer orders the launcher  100 F (corresponding to launcher  100  in FIG. 7A) to launch a ball. This order can take the form of a signal to diode  141  in FIG. 3, which triggers the ONE SHOT. The precise time required for a proper launch will depend upon many factors, so that a trial-and-error process will be required to determine when the launch signal should be issued, and to program the computer accordingly  
         [0089]    If the launch is successful, the truck  200  in FIG. 7B will receive the ball. Then, the truck will launch the ball, as in FIG. 8A. Launcher  100 C will catch it. Then, as in FIG. 8B, launcher  100 C launches the ball to launcher  100 , which then awaits another signal from the computer.  
         [0090]    In the preceding scenario, the truck  200  in FIGS. 7 and 8 launched the ball under its own control. In another embodiment, the truck can be controlled by the computer. In FIG. 19, the presence of the truck  200  at SENSOR  2  can be detected by the computer, and the computer orders the truck  200  to launch the ball at an appropriate time afterward, in order to deliver the ball to launcher  100 F as in FIG. 18B.  
         [0091]    The computer  550  can communicate with the truck using an RF, or infrared, link, as indicated in FIG. 22. Alternately, a “hard-wired” link can be used: path  520  in FIG. 19 can take the form of a model railroad track. Truck  200  can take the form of model train  200 A in FIG. 23. The computer communicates with the train  200 A through the rails of track  520  in FIG. 19.  
         [0092]    In another embodiment, a model train  200 A in FIG. 23 is used, rather than a truck, and the train  200 A runs along railroad tracks. The train  200 A carries two, or more, nets  580 . The computer causes a launcher to launch two balls in rapid succession, each to strike one net.  
         [0093]    The launchers can be adjusted in position by the computer. FIG. 24A shows a servo-mechanism, commonly called a servo. Such mechanisms are commercially available, and are used to control radio-controlled model aircraft. FIG. 24B illustrates a linkage used to rotate a launcher  100 H left-and-right, as indicated by arrows  213 , through rotation of crank  610 . FIG. 24C illustrates a linkage used to move cannon  620  up-and-down.  
         [0094]    It may be desirable to control the exact instant of firing the ball from a vehicle by reference to a station on the ground. FIG. 19A illustrates a disc  535  carried by a mast  536  supported by a base  530 . The base is positioned upon the railroad track  539  as indicated in FIG. 20. The train  200 A in FIG. 21 carries a sensor  540 , which detects the proximity of the disc  535 .  
         [0095]    In operation, the disc  535  provides an approximation of the location for shooting the ball. The delay, controlled by knob  145  in FIG. 3, “fine tunes” the actual time of shooting. Thus, for example, the disc  530  of FIG. 19A would be placed at the position of SENSOR  1  in FIG. 19. After fine-tuning the delay, the train  200 A of FIG. 21 will successfully shoot the ball into launcher  100 C in FIG. 8A.  
         [0096]    [0096]FIGS. 24D and 24E illustrate another embodiment. A launcher  100 M is concealed within a case designed to resemble office furniture. An actuator  570 , through linkage L 1 , raises a LID, or otherwise exposes the launcher, as shown in FIG. 24. A remote control  590 , known in the art, allows an office worker to open the LID, and actuate the launcher  100 M, in order to play a clandestine game of catch.  
         [0097]    Preferably, the remote control  590  is capable of using servos of the type shown in FIG. 24 to adjust the launcher  100 M, so that the worker can remotely adjust the direction, and range, of firing by the launcher. In addition, the remote control  590  allows adjustment of the delay and the power, thus, in effect, allowing remote control of knobs  140  and  145  in FIG. 3.  
         [0098]    [0098]FIG. 25 illustrates another variation, wherein launcher  100 N is fed balls by a miniature basketball basket  620 . This embodiment has the advantage of eliminating long, slender objects, which may injure children.  
         [0099]    [0099]FIG. 26 illustrates another embodiment, wherein launcher  100  is mounted to a clothespin-like clamp  700 . A NET mounts to the launcher  100 . FIG. 27 illustrates this embodiment fastened to a bracket  730  supported by base  430 . A baffle  720  may be added to funnel  410 , to guide the ball B into the basket  105  when caught.  
         [0100]    An advantage of the embodiment of FIG. 26 is that it can be used in a stationary mode, as in FIG. 27, or can be clamped to a vehicle, such as truck  200  in FIG. 7A.  
         [0101]    Many of the FIGS. above show a CONTROL which controls shooting of the ball. FIG. 28 illustrates one architecture for a control  800 . Sensor  120  detects the presence of ball B, and issues a signal on line  810 . Block  820  indicates that nothing happens, at least not automatically, until this signal is received.  
         [0102]    A switch  830  is provided. If the user has positioned the switch in a position calling for continuous, or automatic, shooting of the ball B. block  840  detects this fact, and starts the delay  850 . If the switch is not so set, then automatic shooting does not occur, but may occur for other reasons, as will be seen.  
         [0103]    The user can adjust the delay  850 , as indicated. After the delay, block  870  actuates solenoid  425 , thereby shooting ball B. As indicated, the user can control the power with which the solenoid  425  strikes the ball B. If ball B returns to the launching station  890 , as when another launcher returns it, or a human tosses it into funnel  410 , the steps just described are repeated.  
         [0104]    In addition to the automatic shooting just described, shooting can be triggered in other ways. A remote signal received by block  880  can induce shooting, such as signals received from a computer (or other logic), a sensor, of from a switch actuated by a user, all as indicated.  
         [0105]    [0105]FIG. 29 illustrates a somewhat more hardware-oriented description of the control  800 . OR gate  900  receives signals from the ball sensor  120 , from a switch, from a computer, or from a sensor. When any of these signals is received, delay  910  is triggered. The length of delay is adjustable, as indicated by knob  920 .  
         [0106]    When the delay expires, a signal is applied to line  925 . A second OR gate  930  receives this signal, together with signals from a switch, a computer, or a sensor. (These latter signals can be applied when shooting of the ball is desired without the delay. If a delay is desired, these signals would be applied to OR gate  900  instead.)  
         [0107]    OR gate  930  triggers a switch  940 , which connects a power source  950  withg the solenoid  425 . As indicated by knob  960 , the user can adjust the power source  950 , to control the force with which the solenoid  425  strikes the ball. Circuits which implement the blocks of FIG. 29 will now be discussed.  
         [0108]    In FIG. 30A, delay  910  can be implemented by two SCHMITT triggers  1010  and  1020 , connected through resistor R and capacitor C. FIG. 30B illustrates the steps involved. When V IN−1  goes LOW, as indicated, V OUT−1  goes HI. Capacitor C charges through resistor R, producing the exponential rise of V IN−2 . When V IN−2  crosses the trigger point of SCHMITT  1020 , V OUT−2  goes LOW, as indicated.  
         [0109]    [0109]FIG. 30C summarizes the preceding events in a timing diagram. The DELAY is indicated. As indicated in FIG. 30B, resistor R can be adjustable, thereby allowing adjustment of the delay, as described earlier.  
         [0110]    [0110]FIG. 31 illustrates a circuit for implementing the switch  940  and power source  950  of FIG. 29. Basically, resistor R holds V IN−4  at a LOW state (or a HI state, if R is connected to a high voltage), thereby holding V OUT−4  in a LOW state (or HI state). It will be assumed that V IN−4  is held at a LOW state.  
         [0111]    But when V OUT−3  goes HI, V IN−4  is temporarily pulled HI, but then exponentially decays, as capacitor C charges. When the rising V IN−4  crosses the TRIP point for SCHMITT trigger  1040 , the output of the latter goes LOW, as indicated. Then, when the decaying V IN−4  again crosses the TRIP point, V OUT−4  goes HI again. (Because of the hysteresis inherent in a SCHMITT trigger, the two TRIP points are not identical, but that detail is ignored here.) While V OUT−4  is LOW, the field-effect transistor, FET, is triggered into conduction. This triggering energizes the coil  1050  of the double-pole, double throw RELAY. This energization causes reed  1060  to change to the dashed position, thereby connecting  24  volts across the solenoid  425 , to shoot the ball (not shown).  
         [0112]    As indicated, resistor R is adjustable, to adjust the length of the PULSE applied to the FET, to thereby control the amount of time the solenoid  425  is energized, to thereby control the amount of energy delivered to the ball (not shown). Also, the one-shot which is shown can be replaced by a properly connected  555  timer, as known in the art.  
         [0113]    [0113]FIG. 32 illustrates another approach to controlling the energy delivered to the ball. One of power resistors R 1 -R 4  is selectively placed in parallel with solenoid  425 , byb adjusting the wiper W of rotary switch  1100 . If no resistor is to be placed in parallel, the wiper W is connected to the NC terminal.  
         [0114]    The resistors are of different values. For example, if resistor R 1  equals the resistance of the solenoid  425 , then placing that resistor in parallel with the solenoid  425  will cut the power absorbed by the solenoid in half. Of course, this approach wastes power, but the waste may be tolerated, in the name of simplicity.  
         [0115]    [0115]FIG. 33 illustrates another approach to firing the solenoid  425 . A large capacitor C 1  is connected as shown. FIG. 33 illustrates a type of voltage doubler. Other voltage multipliers are known in the art. FIGS. 34A and 34B illustrate the operation, with non-relevant lines eliminated.  
         [0116]    When the RELAY is in its non-powered state, battery BAT charges capacitor C 1 , as indicated in FIG. 34A. When the RELAY is powered, as in FIG. 34B, the capacitor C 1  is placed in series with the battery BAT, thereby doubling the voltage applied to the solenoid  425 .  
         [0117]    The apparatus of FIG. 33 allows a higher voltage to be applied to the solenoid  425  than is available from battery BAT. In other types of voltage multiplier, two, or more, capacitors are charged through diodes, and then placed in series. For example, if ten capacitors are charged to 9 volts each, when they are placed in series they provide 90 volts of potential.  
         [0118]    [0118]FIG. 35 illustrates a perspective view and a side view of a target T containing a sensor S, as described in the incorporated patents. The sensor S detects a ball-strike by a table tennis ball and produces a signal. When a ball arrives, as in FIG. 36, the signal is fed to a CONTROL, which fires solenoid  425 . A linkage LI causes the target T to pivot, as in FIG. 37, thereby ejecting the ball.  
         [0119]    A close analysis of the sequence will illustrate an interesting fact. It may be thought that the instant at which the target pivots is critical, but such is not believed to be the case. The reason is that the ejection of the ball can be divided into two events: (1) the bounce of the ball from the target, which occurs whether or not the target pivots, and (2) the “swat” issued by the pivoting target.  
         [0120]    By conservation of energy principles, and the principle of superposition in linear systems, it can be shown that it does not matter whether the bounce and the swat are simultaneous, or whether the bounce occurs first. (The third situation, where the bounce occurs after the swat, is clearly impossible, because the bounce causes the swat.) The bounce-before-swat situation is somewhat more likely, due to the processing delay required for the signal issued by the sensor S to become transformed into a power signal reaching the solenoid  425 .  
         [0121]    [0121]FIG. 38 illustrates another embodiment. Launcher  100  launches ball B to a basket BAS. Basket BAS catches the ball, and then drops it, through a hole (not shown) onto a serpentine TRACK. The ball rolls down the track, as in FIG. 40, and then becomes airborne at the END, whereupon it jumps into net  420 . The control circuitry described above senses the return of the ball, and causes the process to repeat.  
         [0122]    [0122]FIGS. 39, 41, and  42  illustrate another embodiment. Two launchers  100  are shown. It is emphasized that the NET, as seen by each launcher, is on the right side of each launcher. However, because the launchers face each other, the cannon C of each faces the NET of the other.  
         [0123]    With this arrangement, the launchers can juggle, if properly configured. For example, in FIG. 39, launcher  100 X launches ball B. Just before the ball B reaches its intended NET, launcher  100 Y launches ball BB. Then, launcher  100 X launches a third ball B 3 , when the first ball B is within NET  1  and ball BB is still in flight. This process continues.  
         [0124]    Figure  42  illustrates the juggling in greater detail. Frame “A” indicates the initial situation, and the box BB indicates symbols for three balls: a hollow ball, a solid ball, and a cross-ball (on the left). In frame B, the hollow ball is launched by the left-hand launcher  100 K, and the cross-ball is loaded immediately into that launcher.  
         [0125]    Then, in frame C, when the hollow ball reaches the 1 o&#39;clock position, the right-hand launcher  100 M launches the solid ball. In frame D, the hollow ball and the solid ball meet at the 2 o&#39;clock position. Next, in frame E, the solid ball is caught by the right-hand launcher. In frame F, which is the mirror-image of frame C, when the solid ball reaches the 11 o&#39;clock position, the left-hand launcher launches the cross-ball.  
         [0126]    Then, in frame G, which is the mirror-image of frame D, the solid ball and the cross-ball meet at the 10 o&#39;clock position. Finally, frame H is reached, which is the same as frame B as to position of balls, and the sequence repeats.  
         [0127]    A single launcher can juggle by itself, as shown in FIG. 43. Details of those particular launchers have been omitted, for simplicity.  
         [0128]    [0128]FIG. 44 illustrates one embodiment. A ball B is positioned at a launching station, adjacent solenoid SOL. Ball B closes a cat&#39;s whisker switch SW, which pulls line L 1  HIGH.  
         [0129]    A digital CONTROL, comprising a microprocessor, such as that sold under the name BASIC STAMP, by Parallax Computing, receives the HIGH signal on line L 1 . Logic executed by the CONTROL is illustrated in FIG. 45.  
         [0130]    The logic idles in block  1600  until switch SW is closed. Then, in blocks  1605  and  1608 , the RC time constants #1 and #2 in FIG. 44 are read by the CONTROL, using instructions programmed into the CONTROL. (Actually, the RC time constant, multiplied by a constant, is read.) Reading these RC time constants allows the user to provide analog inputs to the CONTROL, by adjusting resistors RA and RB.  
         [0131]    These analog inputs indicate the amount of the delay, and the power with which the ball B should be shot. In block  1610  in FIG. 45, the delay is computed. For example, capacitor CA may be 0.1 microFarad, and resistor RA may be adjusted to 5,000 ohms. The CONTROL, in reading the RC time constant, may return a number of 300 as indicating the RC time constant. (Again, this number is not exactly the time constant, but a number related to the time constant.) Block  1610  may divide this number by 30, to produce a delay of 10 seconds.  
         [0132]    In a similar manner, block  1625 , using RC #2, computes a closure interval. This closure interval is the length of time, in milliseconds, for example, which RELAY in FIG. 44 is switched. Closure for a smaller time applies less of the energy of capacitor CC to solenoid SOL.  
         [0133]    Then, in block  1620 , the CONTROL waits for the delay computet and then, in block  1625 , closes the relay for the computed closure interval. The CONTROL executes the closure by applying current to the COIL of the RELAY, through opto-isolator OPTO-ISO.  
         [0134]    A diode D has charged capacitor CC, which is about 3,000 microFarads, to about 90 volts, from wall current indicated as 120 volts AC. Applying current to the COIL causes the REED to connect to terminal T 2 , thereby discharging the capacitor CC into the solenoid SOL.  
         [0135]    In the apparatus of FIG. 44, the solenoid SOL was taken from a standard household door chime, and has a resistance of about 6 ohms. It launched the ball B for a horizontal distance of 15 to 20 feet.  
         [0136]    A USER SWITCH can be provided in FIG. 44. The optional path indicated in FIG. 45 can then be taken, when a closure of the USER SWITCH is detected When the closure is detected, the ball B is shot, through the action of block  1635 .  
         [0137]    The USER SWITCH is indicated as blocks  1640  in FIG. 39, and allows the user to manually control the juggling of the balls. That is, without actually tossing and catching the balls, the user controls the juggling by controlling the timing of the respective launches.  
         [0138]    A ball dispenser  1670  may be provided, which is controlled by a switch SW 3 . The user utilizes this dispenser to deposit the cross-ball indicated in frame B, FIG. 42, immediately after the hollow ball is launched. The incorporated patents describe ball dispensers. Also, a ball dispenser can be constructed by a tube and trap-door, which is actuated by a solenoid, through switch SW 3 .  
         [0139]    The program contained within the CONTROL of FIG. 44 is generated within a microcomputer, such as computer  550  in FIG. 22, and then downloaded into the CONTROL by using line L 5  in FIG. 22. The program is written using an interface available from Parallax Computing for the BASIC STAMP.  
         [0140]    [0140]FIG. 46 is a front view of a basket suitable for use with several of the foregoing embodiments. FIG. 47 is a side view of the basket of FIG. 46. FIG. 48 is a plan view of a cardboard sheet (8.5 inches by 11 inches) which may be manipulated into the basket of FIG. 46.  
         [0141]    The sheet of FIG. 48 is transformed into the basket of FIG. 46 by cutting along the solid lines, and lightly scoring along the dashed lines. The type of dashed line shown between sections I and H designates an interior corner (surface I is folded toward surface H), and the type of dashed line shown between sections H and G designates an exterior corner (surface H is folded away from surface G). For scaling purposes, these two lines should be two inches long, and the square around the circular hole should be one and five-eighths inches by one and five-eighths inches.  
         [0142]    After making the cuts and score lines, fold along opposite edges of the square so that surface E faces toward surface F. Next, fold along other opposite edges of the square so that surfaces B face away from one another. Next, fold between sections B and A so that surfaces A face away from the circular hole and portions of sections A overlap one another. Next, staple sections A to one another to define a square opposite the circular hole. The resulting square and the flaps on sections B form a “base” to be disposed about the launcher.  
         [0143]    After the “base” is complete, fold along lines between sections D and section E so that surfaces D face toward one another. Next, fold along lines between sections C and D so that surfaces C face toward surface E and portions of sections C overlap both one another and section F. Next, dispose tape about the resulting “box” or “tube”.  
         [0144]    After the “box” is complete, and the outermost portions of the sections G have been removed, fold each surface K toward surface J and then back again. Next, fold each surface G away from its adjacent surface H; fold each surface H toward its adjacent surface I; and fold each surface I toward surface J. On one side at a time, insert section G inside the box so that the fold line between sections G and H coincides with the top of the box. Staple section G to section D and then repeat for other side. Finally, staple each section K to adjacent section H.  
         [0145]    [0145]FIG. 49 shows a flow chart suitable for controlling the launching of balls between two juggling stations constructed according to the principles of the present invention.  
       Additional Considerations  
       [0146]    A table tennis ball can be used as the projectile  8  in FIG. 1. Such balls weight about 0.1 ounce.  
         [0147]    A “capture cross-section” of the basket  105  in FIG. 1 can be defined. This term refers to the area of the “inlet” or “mouth” of the basket, through which the ball B passes while being captured. In one embodiment, a capture cross section of 150 square inches is contemplated. In another, the capture cross section is 15 times the cross-sectional area of the ball.  
         [0148]    The capture cross section can also be defined in terms of angles, analogous to the spherical coordinates used in trigonometry. These angles bracket the paths of the incoming ball. For example, if the basket can catch balls, from those travelling horizontally, to those travelling vertically, the angle would range from zero (horizontal) to ninety (vertical). A similar approach can be applied in the horizontal direction. For example, if the basket can catch balls incoming from the east, and the north, and all angles in-between, it would capture angles spanning 90 degrees.  
         [0149]    In one embodiment, the basket is sturdy enough to capture a table tennis ball, but not to capture a golf ball. The mass of a golf ball is a defined quantity. One reason is to limit play to harmless balls.  
         [0150]    In one embodiment, the basket is effective to capture balls which have been airborne for 15 feet, and cannot capture ground-borne balls, such as rolling balls.  
         [0151]    Numerous substitutions and modifications can be undertaken without departing from the true spirit and scope of the invention. What is desired to be secured by Letters Patent is the invention as defined in the following claims.