Abstract:
A ground-based ball launcher for inflated-ball sports practice provides an impulse that propels the ball upwardly in a trajectory of pre-adjustable angle and velocity so as to obtain a desired maximum height and landing distance offset from the launcher. An optional adjustable time delay gives a player time to move into place and get set for each launching. Launching energy may be provided by a compressed coil spring which can be reloaded by the user with foot-pump action.

Description:
FIELD OF THE INVENTION 
   The present invention relates to the field of sports equipment and more particularly to a sports ball launcher for use in practice of games that utilize an inflated ball, including basketball, volleyball and soccer. 
   BACKGROUND OF THE INVENTION 
   Many basketball players devote substantial time to practice activities, sometimes in groups or pairs, but often alone so that practice is normally limited to aspects of the game that do not require the presence of another person, e.g. dribbling and making hoop shots. Activities such as catching high passes and rebounds and face-off jumping normally require the presence and participation of at least one other person besides the player(s), e.g. a player or coach to throw the ball. Two players practicing face-off jumping require a third person to make a fair toss. 
   DISCUSSION OF KNOWN ART 
   U.S. Pat. No. 5,575,482 discloses a SPORTS BALL LAUNCHER for basketballs, powered by elastic propulsion bands and features a two-wheeled cart and a ball-loading trough from which sequential launching can be automatic or manually controlled. 
   U.S. Pat. No. 4,164,928 discloses a BASKETBALL TOSSING DEVICE that is hand-held and thus is not practical for solitary practice U.S. Pat. No. 221,694 discloses a Spring-Trap for Throwing Target-Balls (volleyballs) vertically, that can be triggered remotely by a trip line. 
   These and other ball launchers of known art are less than satisfactory for solitary practice: upon initiating the launch manually (including the first launch in an automatic series) the player would not have sufficient time to move into place and get properly set for a jump, therefore satisfactory practice with such launchers would require the presence of another player or assistant to initiate the launching. 
   OBJECTS OF THE INVENTION 
   It is an object of the invention to provide a launcher for practicing basketball, or other inflated ball game such as volleyball, that can be controlled by a player in a manner to launch a ball conveniently and consistently without impacting the quality of the practice or the fairness between two players and without requiring the services of an additional person besides the player(s). 
   It is a further object to arrange for the player(s) to be allowed adequate time to get set in place for a launch. 
   It is a further object to enable the player to make pre-launch adjustments affecting the trajectory of the ball with regard to maximum height and landing distance offset from the ball launcher. 
   SUMMARY OF THE INVENTION 
   The objects of the present invention have been met in a ground-based inflated ball launcher, intended for solitary or one-on-one player sports practice, that provides an impulse of force that launches the ball upwardly in a trajectory of pre-adjustable velocity and angle of vertical inclination so as to obtain a desired maximum height and landing distance offset from the launcher. An adjustable timer allows a player to initiate a launch with enough time delay to then move into place and get set before the actual launch of the ball. In a preferred embodiment, the launch is powered by decompression of a coil spring that becomes compressed for loading by the user foot-pumping a treadle pad. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a three-dimensional view of a sports ball launcher in accordance with a preferred embodiment of the present invention. 
       FIG. 2  is an enlarged view of an inclination gage on the left hand side of  FIG. 1 . 
       FIG. 3  is a three-dimensional view of a lower portion of the launcher of  FIG. 1  showing the treadle pad in its folded standby position. 
       FIG. 4  is a cross-section of the launcher of  FIG. 1  taken through a central axis showing a first internal implementation with the launcher in the unloaded condition. 
       FIG. 5  is a side view of the plunger core assembly of the launcher of  FIG. 4 . 
       FIG. 6  is a cross-section of the hinge joint portion of the launcher of  FIG. 4 , taken in a perpendicular plane. 
       FIGS. 7–9  are cross-sections of the launcher of  FIGS. 1 and 4  showing sequential steps in foot-pump loading. 
       FIG. 10  is a cross-section of a launcher with the external appearance of  FIGS. 1–3 , but containing alternative internal implementation. 
       FIG. 11  is a side view of the plunger core assembly of the launcher of  FIG. 10 . 
       FIG. 12  a cross-section of the hinge joint portion of the launcher of  FIG. 10  taken in a perpendicular plane. 
       FIG. 13  depicts the trajectory of a launched ball. 
   

   DETAILED DESCRIPTION 
     FIG. 1  is a three-dimensional view of an illustrative embodiment of a sports ball launcher  10  in accordance with the present invention. An inflated ball  12 , typically a basketball, is supported in a resilient bowl-shaped ball holder  14  extending upwardly from upper tubular member  16 . 
   A timer module  18 , attached to tubular member  16  near its upper end, is equipped with a knob  18 A for setting a delay time for delayed launch and a pushbutton  18 B for triggering an immediate launch. 
   A hinge joint assembly  20  includes two mating portions: upper portion  20 A extending up into the lower end of upper tubular member  16  and lower portion  20 B extending down into the upper end of lower tubular member  22 . Portions  20 A and  20 B are seized together firmly by tightening clamp knob  20 C, which can be released and re-tightened to reset the inclination of upper tubular member  16  relative to the vertical orientation of lower tubular member  22 . 
   Hinge joint  20  is designed to limit the maximum angle of inclination available so that there is no risk of upsetting the launcher  10  off its base  24 . 
   The lower end of lower tubular member  22  engages hub  24 A of a reinforced circular base  24  which is made sufficiently large in diameter, e.g. 14 inches, to provide overall stability of launcher  10 . 
   A treadle pad  26 , mounted on an arm that extends through a vertical slot  24 B in hub  24 A of base  24 , enables a user to load the launcher  10  by reciprocating foot-pump action on treadle pad  26 . The extending arm is configured with a hinge  26 A, located near hub  24 A, by which the treadle pad  26  can be folded upwardly when not in use, for purposes of personnel safety. 
     FIG. 2  is an enlarged view of an inclination gage that can be located on the left hand side of hinge joint  20  ( FIG. 1 ). A pointer  20 D, affixed to upper tubular member  16 , co-operates with a scale  20 E on the lower tubular member  22 , which may be calibrated in degrees as shown: 0, 5, 10, 15 (degrees), for example. 
     FIG. 3  depicts the lower portion of  FIG. 1  with treadle pad  26  folded upwardly at hinge  26 A to a standby location against tubular member  22  for purposes of personnel safety. 
   Also, for purposes of safety, in addition to making ball-holder  14  and base  24  from resilient material, harder surfaces such as tubular members  16  and  22 , and the underside of treadle pad  26  are preferably covered with soft foam material. 
     FIG. 4  is a cross-sectional view of the launcher  10  of  FIG. 1 , taken through its central axis and through the center of treadle  26 , showing a first internal implementation wherein treadle pad  26  is directly coupled to a pumping mechanism located in hub  24 A of base  24 . 
   Ball holder  14  is attached to the upper end of tubular member  16 , preferably in a threaded manner as shown, and is configured with a resilient circular membrane  14 A in the region immediately beneath ball  12 , through which the ball  12  is impacted for launching. Membrane  14 A serves to keep dirt and debris out of the interior of launcher  10  and to avoid any damage to ball  12  when launched, thus membrane  14 A must be made sufficiently durable to withstand repeated launchings yet resilient enough to provide sufficient transfer of energy to the ball  12 . 
   Shown in place in  FIG. 4 , and also shown separately in  FIG. 5  for clarity, a centrally-located plunger core assembly  28 , includes an upper plunger rod  28 A fitted with a metal striker cap  28 B at its upper end, an annular coil drive collar  28 C securely fastened to upper plunger core rod  28 A in an upper central region thereof as shown, a connection link  28 D connected to lower end of upper plunger core rod  28 A, a lower plunger core rod  28 E connected to the lower end of connection link  28 D and an annular recoil spring support collar  28 F securely fastened to the upper end of lower plunger core rod  28 E as shown in  FIG. 4  supporting recoil spring  36 . Plunger core rods  28 A and  28 E are typically made from stainless steel 5/16″ in diameter and connection link  28 D is preferably made from stainless steel cable about ⅛ inch in diameter, but could be made from steel wire. 
   The plunger core assembly  28  moves as a whole in a longitudinal, i.e. substantially vertical, work stroke in which vertical movement of rods  28 A and  28 E ( FIG. 4 ), is controlled by two corresponding unidirectional grip modules  32  and  34 . 
   Unidirectional hold/release module  32  is securely fastened inside tubular member  16  near its upper end. A steel hold/release grip plate  32 A is constrained at its right hand end by an overhead fulcrum and is configured at its left hand end with a drive arm that extends into timer  18  through vertical slot  16 A configured in the wall of member  16 . Grip plate  32 A is held in a “floating” manner along with an associated steel coil spring  32 B beneath, in a metal shell  32 C which is securely fastened to upper tubular member  16 . 
   A main steel coil spring  30  is located within tubular member  16 , bearing against coil drive collar  28 C at the upper end and supported at the lower end on upper hinge portion  20 A, which is configured with a central clearance bore which is dimensioned to guide the lower end of upper plunger rod  28 A, and flared to a larger bottom opening to accommodate link  28 D for different angles of inclination as set by hinge joint  20 . 
   A central clearance hole in plate  32 A is dimensioned for a close clearance fit rod  28 A so that when plate  32 A is inclined away from perpendicular to rod  28 A as shown, urged clockwise by upward bias of spring  32 B and fulcrum constraint at the right hand end, the edges of the central clearance hole of plate  32 A exert a strong binding friction action on rod  28 A that prevents any upward travel of rod  28 A. This binding friction action is positively re-enforced: it actually intensifies as the spring  30  become further compressed and the required holding force increases. However, following launching, with the coil holding force removed, plate  32 A repositions slightly counterclockwise so as to release the grip on rod  28 A and allow the plunger assembly  28  to travel downwardly as required in the re-loading pump strokes. 
   Recoil spring  36 , resting on the top side of coil support collar  28 F of rod  28 E, with its top end constrained against the bottom end of hinge portion  20 B, is relatively weak, serving to stabilize lower plunger rod  28 E against overshooting during the launch stroke and ensuring that, after launching, plunger assembly  28  returns to its proper location in the unloaded condition as shown in  FIG. 4 , avoiding risk of deformation of membrane  14 A by strike head  28 B. 
   A unidirectional loading grip module  34 , located and securely fastened in the lower end portion of lower tubular member  22  within hub  24 A includes a pump grip plate  34 A held in the horizontal position shown against the lower side of a solid bulkhead collar  34 B by a coil spring  34 C which is supported on a portion of base  24 . Bulkhead collar  34 B is securely fastened to tubular member  22  and is configured with a central clearance hole that guides the upper end of lower rod  28 E whose lower end is guided and constrained in a clearance hole configured in base  24  as shown. With pump grip plate  34 A located horizontally as shown, its central clearance hole allows lower rod  28 E to move freely up or down; however rod  28 E is held in the upward location of the plunger core assembly as shown by link  28  due to light force from main coil spring  30  which is at or near in its full length in this unloaded condition, holding upper rod  28 A in this upward location via coil drive collar  28 C. 
   The pump drive grip plate  34 A extends through a vertical slot  24 B configured in hub  24 A and in lower tubular portion  22 , and is coupled by a hinge joint  26 A to treadle pad  26 , whose lower side is covered with a foam layer  26 B. 
     FIG. 6  is a cross-section of the region of hinge joint  20  of  FIG. 3 , taken through a central plane that is perpendicular to that of  FIG. 4 , as viewed from the left hand side of  FIG. 4 . The upper hinge joint portion  20 A is configured with a hub extending into lower hinge joint portion  20 A and having a threaded central opening that engages the threaded shaft of knob  20 C, to enable joint  20  to be secured at a desired angle of inclination. The central vertical openings in portions  20 A and  20 B are seen providing guidance for the lower end of upper rod  28 A and clearance for link  28 D. 
     FIGS. 7–9  show cross-sections of launcher  10  in sequential steps of loading launcher  10  by pumping treadle pad  26 , following the unloaded starting condition shown in  FIG. 4 . 
     FIG. 7  shows treadle pad  26  having been initially depressed as indicated by the arrow, normally by foot by the user, to about half of its full pump stroke length, causing pump grip plate  34 A to initially rotate slightly counterclockwise until its central hole grips rod  28 E and to then pull the plunger core assembly ( 28 ,  FIG. 5 ) downward to the location shown, creating the separation now seen at the top end between membrane  14 A and striker cap  28 B. 
   As the plunger core assembly moves downwardly, in the hold/release grip module  32 , hold/release grip plate  32 A, rotating slightly counterclockwise as shown, indicated by the small separation from pushbutton  18 B seen in timer  18 , allows the upper rod  28 A to move downwardly, pulled down by link  28 D in response to downward movement of lower rod  28 E as driven by grip plate  34 A from foot pressure on treadle pad  26 . 
     FIG. 8  shows treadle pad  26  having been further depressed to the lower end of its pump stroke causing full compression of spring  34 C, the plunger core assembly having been pulled down to the further downward location indicated by the increased separation now seen at the top end between membrane  14 A and striker cap  28 B. At this initial loading condition of launcher  10 , i.e. partial compression of main spring  30 , the disposition of the plunger assembly is indicated visually to the user by a mark on collar  28 C that is visible through vertical slot  16 B immediately below timer  18 . 
   When the foot is lifted from treadle  26  for another pump stroke, the treadle  26  and pump grip plate  34 A will be automatically returned to their uppermost position (as seen in  FIGS. 4 and 9 ) by the expansive force of spring  34 C; however the hold/release grip module  32  will prevent any upward travel of the plunger core assembly as grip plate  32 A rotates clockwise to its gripping condition by expansion of spring  32 B, gripping onto rod  28 A; as seen in timer  18 , the extending arm of grip plate  32 A has returned to its normal “hold” location immediately beneath pushbutton  18 B as in  FIGS. 3 and 7 . Thus the compression in spring  30  that has occurred in consequence of the first foot pump stroke is retained, and the corresponding potential energy now stored in spring  30  is available for launching. 
   At this stage, a weak launch could be performed by actuating timer  18  or pushbutton  18 A; however, more typically, further pumping will be performed via treadle  26 , repeating the pump stroke cycle described above in connection with  FIGS. 4 ,  7  and  8  for as many pump strokes as necessary until a desired load stress in spring  30  has been reached, as indicated by the mark on collar  28 C, viewed through vertical slot  16 B. 
     FIG. 9  shows the launcher  10  having been loaded by pumping to its maximum capability with the plunger core assembly pulled down to the lower limit of its travel range and spring  30  fully depressed, as indicated by the mark on collar  28 C at the lower end of vertical slot  16 B. 
   After the launcher  10  has been loaded to the desired launch strength, launching is executed by actuating timer  18  or pushbutton  18 A: depression of the extending arm of hold/release grip plate  32 A releases upper rod  28 A and thus releases the plunger core assembly to travel rapidly upward as driven by the force of spring against collar  28 C so that drive head  28 B launches the ball  12  upwardly by striking membrane  14 A. 
     FIG. 10  is a cross-sectional view taken through the center of a launcher  10 A which, while virtually identical in external appearance and in functional operation to launcher  10  ( FIGS. 1–9 ) is implemented differently internally. 
   As shown separately in the side view of  FIG. 11 , plunger core assembly  38  utilizes only a single rod  38 A, fitted with striker head  28 B and collar  28 C, similar to the upper rod portion in launcher  10 , but no longer requiring the connector link  28 D ( FIGS. 4–9 ) and the associated rod fastenings at both ends. In launcher  10 A ( FIG. 10 ), a pump grip module  40 , functionally equivalent to pump grip module  34  ( FIGS. 4–9 ) is located inside tubular member  16 , immediately above the hinge joint  42 . Pump grip plate  40 A, engaging rod  38 A directly, is urged upwardly against the horizontal bottom surface of collar  40 B by pump grip spring  40 C, which is supported on hinge portion  42 A. Collar  40 B, securely fastened to upper tubular portion  16 , provides the bottom end support of main spring  30 . 
   Pump grip plate  40 A is actuated by a connector link  44  which is driven by a lever system at the bottom including treadle  26  connected by hinge  26 A to a pump lever arm  46  whose right hand end is pivoted to the right hand side of lower tubular portion  22  and base hub  24 A by a hinge or fulcrum constraint. This arrangement provides leverage gain at the treadle  26 , and thus can br designed to operate at reduced pumping force and increased length of vertical pump stroke compared to the direct pump drive in launcher  10 . 
     FIG. 12 , corresponding to  FIG. 6 , is a cross-section of the region of hinge joint  42  of  FIG. 10 , taken through a central plane that is perpendicular to that of  FIG. 10 , as viewed from the left hand side of  FIG. 10 . The upper hinge portion  20 A and lower hinge portion  20 B are seen to be generally symmetrical in outline. The threaded shaft of knob  42 C traverses a clearance hole in lower portion  42 B and engages a threaded hole in upper portion  42 A, providing the same adjustment capability as in the previously described hinge joint ( 20 , FIGS.  3 , 4 ) for setting the upper tubular portion  16  at a desired inclination from the vertical lower tubular portion  22  to obtain a desired trajectory of a launched ball  12 . 
   Apart from the differences described above, the remaining structure of launcher  10 A and the loading and launching procedure are essentially the same as described above in connection with the first implementation: launcher  10  ( FIGS. 2–7 ). As in launcher  10 , plunger core rod  38 A is typically made from stainless steel 5/16″ in diameter and connection link  44  is preferably made from stainless steel cable about ⅛ inch in diameter, but could be made from steel wire. 
     FIG. 13  depicts the trajectory  46  of a ball  12  launched by launcher  10 . Yv represents the maximum height that ball  12  would reach, as determined by the loaded spring force, with the hinge joint set for zero inclination to launch ball  12  straight up in purely vertical direction. 
   Path  46  represents the parabolic trajectory of ball  12  when launched at an angle a of inclination from vertical, 5 degrees as shown, and Y represents the maximum height of path  46 . 
   In the following calculations, the effect of air friction on the ball is neglected as negligible, apart from the potential influence of wind. 
   For simplification, instead of referencing to ground level, calculations are referred to the elevation at the top end of the launcher  10 , typically 4 to 5 feet above ground which is about shoulder-level of player  48 . Thus, for Y=30 feet, the actual height would be 34 to 35 feet above ground level. 
   The reduced height due to inclination Y/Yv can be calculated from Yv*cos(a), this relatively small: about 3.5% for a=15 degrees and proportionately less for smaller angles. 
   It is of particular interest to the user to be able to estimate the horizontal distance X of the ball landing point from the launcher  10  as a function of maximum height Yv. This can be estimated from X=4*Yv*sin(a): thus for Yv=30 feet and a=5 degrees, X=10.46 ft., a reasonable working distance. 
   The airborne time period can be found from the calculus-derived basic rule of gravity for a falling body, Y=−(g/2)*t^2 =−16*t^2, the one-way time, which is the same for the up path as for the down path, can be calculated as t=(Y/16)^−2: for this example t=1.37 seconds, thus the total airborne time is 2*t=2.74 seconds. 
   The horizontal velocity can be calculated by first calculating the “muzzle velocity” from Vm=g*t: for this example 32*1.37=43.84 ft/sec i.e. 29.88 mph, from which the horizontal velocity can be calculated: Vh=Vm*sin(a), i.e. Vh=3.82 ft/sec (2.6 mph) for this example. 
   This indicates that the influence of wind must be considered mind since a 3 mph wind is roughly equivalent to a 5 degree inclination, and could substantially double or nullify the effect of the 5 degree inclination, depending on the wind direction. 
   In the above described implementations, the friction gripping principle for driving a rod, including a pump module and a hold/release module, each utilizing a tilted grip plate with a central binding hole and typically spring-loaded, is known and used in common apparatus such as caulking guns for its ability to drive a rod longitudinally with a pumping action in a simple and economical manner. Also a similar form of hold/release module is utilized as an adjustable stop that fits onto a pipe member of a utility clamp system. It is well known that this principle of positively re-enforced frictional uni-directional binding action can be utilized with many different locations and arrangements of the two modules anywhere along a working region of the rod as alternatives to the particular locations and arrangements described above and shown in the drawings. 
   Unidirectional drive functions for pumping and hold/release can also be accomplished by application of principles other than frictional binding, through the use of standard mechanical apparatus such as ratchet gears with spring-loaded pawls, rack-and-pinion arrangements, and the like, however such implementation would tend to be substantially more costly. 
   As an option, the invention could be practiced in simplified manually-launched embodiment wherein timer  24  is omitted and launching is initiated by simply depressing an extending portion of the grip plate of the hold/release module as the manual launching control. 
   An electrical actuator coupled to the extending release arm of grip plate  34 A would open the possibility of utilizing wired or wireless remote control, with or without the provision of a timer. 
   As an alternative to a mechanical timer, electrical implementation would work in conjunction with an electrical actuator and could indicate delay time on a numeric readout. Alternatively the time delay could provided by other methods such as hydraulic or pneumatic. 
   As an alternative or supplement to spring  32 , motive force for launching could be provided pneumatically, hydraulically or electrically by adapting known technology. Thus the need for manual pumping could be eliminated or minimized, and other methods of adjusting the force and resulting ball height would be facilitated. 
   As an alternative to loading by foot-operated treadle as described above, a hand-operated pump could be provided to operate in a similar manner: a pump handle could be mounted at a convenient height at a chosen location on the tubular body of the launcher and coupled directly, or by internal or external linkage to the pump grip module. 
   As alternatives to hinge joints  20  or  42  as shown above, a locking or high friction ball joint could be employed, or a “gooseneck” arrangement with stiffly flexible corrugated tubular construction for at least some portion of the main tubular body. 
   There are additional variations utilizing hand, foot or powered loading with which the invention may be practiced. 
   Instead of utilizing the compressed condition of the coil spring to store energy for launching, the stretched condition could be utilized, either with a coil spring or other commercially available stretch cord. 
   The invention may be embodied and practiced in other specific forms without departing from the spirit and essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description; and all variations, substitutions and changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.