Abstract:
The invention relates to a ball projecting apparatus having a ball singulator with a fork-and-actuator mechanism that is adjustable to allow the apparatus to be used for a variety of different sports. A fork assembly is adjustable or replaceable to convert the apparatus from use with balls of one sport to use with balls of a different sport. Each fork may be referred to as a “rocker,” since it is pivoted from a first position in which a foremost ball is impeded from advancing to a second position in which the foremost ball is released, but the next ball is impeded. The rocking motion alternates which of two prongs is within the ball-supply path. When the forward prong is in the ball-supply path, all balls are prevented from advancing. Alternatively, when the rearward prong is in the ball-supply path, the foremost ball is allowed to advance.

Description:
TECHNICAL FIELD 
     The invention relates generally to devices that are used to project a sequence of balls at a controlled rate and more particularly to such devices that are easily converted from use with one given-sized ball to a significantly different-sized ball. 
     DESCRIPTION OF THE RELATED ART 
     There are a number of available devices which are used to improve the playing skills of participants of a particular sport. Ball tossing devices are commonly used in such sports as tennis, baseball and softball to develop hitting and catching skills. Ball tossing devices may also be useful for sports in which the ball is significantly larger (e.g., soccer) and/or has a shape other than a sphere (e.g., American football). 
     U.S. Pat. No. 4,669,444 to Whitfield et al. describes a ball tossing apparatus which varies the direction of successive tosses. The apparatus includes a cam mechanism which extends to the exterior of a housing. Rotation of a cam shaft changes the tilt angle of the housing and the direction of the next toss. The apparatus may be used in a hitting practice or a fielding practice in such sports as baseball and softball, but different sports require different embodiments of the apparatus. 
     A ball pitching device is described in U.S. Pat. No. 5,562,282 to Stevenson. The device is particularly adapted for use in softball, since it simulates the mechanics of an underhand fast pitch. A pitching arm is pivoted to a ball-engaging position, where it receives a ball from a supply chamber. The pitching arm is caused to pivot forwardly to project the ball. The pitching arm then returns to its ball-engaging position to receive a next ball. 
     While the known devices operate well for their intended purposes, the devices are not easily adapted for use in different sports. Thus, a supplier may need to provide a different device for sports in which balls have different sizes. Even within the same sport, the regulation ball may vary. For example, most governing bodies of organized softball dictate a 12-inch (30.48 cm) regulation softball, but allow an 11-inch (27.94 cm) softball for younger players, such as those in ten-and-under age leagues. For some ball tossing devices, this difference in ball size makes the difference between whether a particular machine may be used or is unsuitable. 
     Not all devices are restricted to use with a single ball. U.S. Pat. No. 5,066,010 to Pingston describes a ball dispensing machine that may be used for different-sized balls. The machine includes a carrier from which a ball is dropped, so that a player can attempt to hit the ball before it reaches the ground. The carrier has a relatively large U-shape, but guide bars may be inserted into the carrier to reduce the dimensions. As a result of the insertable guide bars, the machine is adaptable to be used in sports having different-sized balls. However, there are sports skills that are best practiced by utilizing a means for projecting the ball, rather than dropping it. Thus, the Pingston machine is versatile with respect to the selection of the ball, but its versatility is somewhat limited with respect to the range of skills that can be developed. 
     What is needed is a ball projecting apparatus which may be used to practice skills in a variety of different sports. 
     SUMMARY OF THE INVENTION 
     A ball projecting apparatus in accordance with the invention includes a singulator that has a fork-and-actuator mechanism that is adjustable to allow the apparatus to be used for a variety of sports. The positions of fork prongs relative to each other and to a ball-supply path determine the dimensions of the balls for which the singulator is currently suited. In the preferred embodiment, the apparatus includes a set of forks, so that the fork can be changed in order to convert the singulator from use in one sport to use in another. However, the adjustment may be made on a single fork, if the fork is designed to enable adjustments. 
     The fork of the singulator may also be referred to as a rocker, since it is pivoted between either a first position in which a foremost ball along the ball-supply path is impeded from advancing or a second position in which the foremost ball is released, but the next ball is impeded. Typically, the ball-supply path is a gravity-feed ball path. When the fork is in the first position, a forward prong of the fork contacts the downstream surface of the foremost ball. However, by rocking the fork to the second position, the forward prong rises above the level of the foremost ball, while the rearward prong is lowered to prevent the next ball from advancing with the foremost ball. 
     The fork prongs extend in a direction that is generally perpendicular to the ball path. In the preferred embodiment, each fork includes a metallic plate from which the fork prongs are cantilevered. In this embodiment, the fork that is presently mounted within the apparatus can be easily removed and replaced with another fork that is designed for a different-sized ball. However, other embodiments are contemplated. For example, each fork may have a pair of plates that are connected at opposite ends of the fork prongs. 
     In addition to changing the distance between the two fork prongs, a conversion from one sport to another sport may require an adjustment of the space between each prong and the ramp that forms the ball-supply path. This adjustment may be accomplished by varying the length of an actuator arm which controls the rocking of the fork. 
     The apparatus also includes a projection mechanism for releasing the ball that is within a firing chamber of the apparatus. Preferably, the projection mechanism is also sport-neutral (i.e., does not restrict the apparatus to use for balls of a particular sport). A ball may be projected by first relaxing a belt and then tensioning the belt to propel a ball that is resting on the belt. Since the relaxed belt will conform to the shape of the ball, the dimensions of the ball are not critical to proper operation. Thus, the invention is easily adapted for use in sports that include volleyball, basketball, lacrosse, etc. In fact, if the ball feeding mechanism is properly constructed, the invention may be used in sports having non-spherical balls (e.g., American football) or in hockey if the hockey pucks are fed into the apparatus so that they roll along their circumferential edges as they progress along the supply path. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of a ball projecting apparatus having an adjustable fork-and-actuator mechanism in accordance with one embodiment of the invention. 
     FIG. 2 is a top view of the apparatus of FIG. 1, with selected components being shown for greater clarity. 
     FIG. 3 is a side view of the apparatus of FIG. 1, but with the adjustable fork-and-actuator mechanism in a ball-release position. 
     FIG. 4 is a side view of the fork-and-actuator mechanism of FIG.  1 . 
     FIG. 5 is a perspective view of the fork of the mechanism of FIG.  4 . 
     FIG. 6 is a rear view of the fork of FIG.  5 . 
     FIG. 7 shows a two-piece set of alternative forks for use in the apparatus of FIG.  1 . 
    
    
     DETAILED DESCRIPTION 
     With reference to FIG. 1, a sport-convertible apparatus  10  is shown as including a housing  12  in which balls  14 ,  16 ,  18 ,  20  and  22  are gravity-fed along a ball-supply path to a firing chamber  24 . As will be described in detail below, the apparatus includes a singulator that can be adjusted from one that handles a given-sized ball to one that handles a different-sized ball. Many of the features that are unrelated to the adjustable singulator are described in U.S. Pat. No. 4,669,444 to Whitfield et al., which is hereby incorporated by reference. 
     The apparatus  10  includes a pair of adjustable legs  26  and  28  from which an internally threaded lower portion telescopes by manually rotating the attached feet  30  and  32 . The rearward leg  28  is longer, so that the balls  16 - 22  along the supply path formed by a ramp  34  abut each other while being pulled by gravity toward the singulator position of the foremost ball  16  and then from the singulator position to the firing chamber  24 , as indicated by ball  14 . The use of the legs  26  and  28  is not critical to the invention, since other means for achieving the desired slant of the apparatus  10  may be substituted. 
     Referring now to FIGS. 1 and 2, the apparatus includes a cylindrical sleeve  36  that provides the opening through which the balls  14 - 22  are introduced. A hopper (not shown) or similar device may be connected to the sleeve to provide a continuous supply of balls to the apparatus. There is also an opening through the housing  12  to the firing chamber  24 , so that the ball  14  may be projected through the opening. Four cylindrical ball guides  38 ,  40 ,  42  and  44  seat the ball  14  within the firing chamber and guide the ball when fired. 
     A single motor assembly  46  is used to drive all of the functions of the apparatus  10 . A fan  48  is used to provide cooling. Preferably, the motor assembly includes an electric motor, but other types of motors may be substituted. While not shown in FIGS. 1 and 2, the motor assembly drives rotation of a continuous chain, such as the bicycle-type chain described in the above-referenced patent to Whitfield et al. The chain includes one or more actuating members  50  that determine the timing of the repeating operations, as will be explained more fully below. 
     A number of non-critical features are illustrated in FIGS. 1 and 2. For example, the shield for protecting the moving parts is included in the drawings. The shield has a pair of end plates  52  and  54  and has upwardly projecting elongated members  56  and  58 . A beneficial, but optional, feature provides adjustable tensioning of a projection belt  60 . It is the projection belt that is manipulated to fire the ball  14  from the firing chamber  24 . The tension on the belt determines the force that will be applied to the ball. One end of the belt  60  is secured to a rod  62  that extends between a pair of posts  64  and  66 . For example, a loop may be formed at the end of the belt and the rod may pass through the loop. The opposite end of the belt is similarly connected to a rod  67 , which passes through a spring-loaded member  68  that is allowed to travel within a slot  70 . As shown in FIG. 1, a coil spring  72  biases the spring-loaded member  68  rearwardly, so that the projection belt  60  is pulled into a taut condition. The tension provided by the coil spring is adjustable by rotating an external knob  74  at the rearward end of the apparatus  10 . Counterclockwise rotation of the knob  74  may increase the tension on the belt  60 , while clockwise rotation decreases the tension. 
     Some of the mechanical features for implementing the belt-tensioning adjustment are shown in FIGS. 1 and 2, but other arrangements may be substituted. An end of the coil spring  72  is connected to a rotatable shaft  76  that is manipulated by the external knob  74 . A brace has upper and lower horizontal portions  78  and  80  at opposite ends of a vertical portion  82 . The upper horizontal portion  80  is secured to a tube end plate  84  through which the tension shaft  76  passes. 
     A critical feature of the apparatus  10  is the adjustability of a fork-and-actuator mechanism. Referring to the top view of FIG. 2, this mechanism includes a forward prong  86  and a rearward prong  88 . The prongs are cantilevered from a fork plate  90 . While the cantilevered arrangement provides an advantage with regard to replacing the fork assembly in order to accommodate a different-sized ball, there may be embodiments in which it is preferable to have fork plates at both ends of the prongs  86  and  88 . The spacing between the two prongs plays an important role in determining the size of the ball for which the apparatus is best suited. Moreover, the positions of the prongs relative to the ramp  34  that defines the ball-supply path plays an important role in reliably separating the foremost ball for advancement into the firing chamber  24 . The spacing between the two prongs should be generally equal to the diameter of the balls. The distance between the prongs and the ramp should be such that when the fork plate  90  is rocked about a pivot axis, the prongs individually alternate between being spaced from the ramp by a distance less than the diameter of the balls and being spaced from the ramp by a distance greater than the diameter of the balls. 
     The manipulation of the fork prongs  86  and  88  will be described in greater detail with reference to FIGS. 3 and 4. However, the structure of the fork itself can be best seen in FIGS. 5 and 6. The fork plate  90  includes internally threaded bores into which the threaded ends  92  and  94  of the prongs  86  and  88  are attached. The prongs should be sufficiently long to ensure that a ball cannot pass to the outside of the prongs while progressing along the ball-supply path of the apparatus. 
     A lever clamp  96  fits within a cutaway region of the fork plate  90  and is held in position by a pair of fasteners  98 . The lever clamp secures a fork shaft (not shown) in position when the fork assembly is mounted for rocking motion within the apparatus. With the lever clamp in place, an opening  100  has a shape that corresponds to the end of the fork shaft. 
     FIGS. 1 and 4 show the fork in a first position, while FIG. 3 shows the fork in a second position. As best seen in FIG. 1, the first position is one in which the forward portion of the fork plate  90  is lowered, so that the forward prong  86  blocks the path of the foremost ball  16 . Thus, the foremost ball is impeded from further travel along the ball-supply path to the firing chamber  24 . On the other hand, in the second position shown in FIG. 3, the forward prong  86  is raised above the level of the foremost ball, allowing the ball  16  to roll toward the firing chamber  24 . In the figure, the ball  16  is shown in a position just prior to dropping into the firing chamber. While the forward portion of the fork  90  is raised, the rearward portion of the fork is lowered, so that the rearward prong blocks the path of the next ball  18 . 
     In a simplified explanation of the singulation operation, the timing of the release of balls to the firing chamber  24  is determined merely by rocking the fork plate  90 . When the fork plate is angled downwardly from its rearward portion to its forward portion, all of the balls waiting to enter the firing chamber  24  are impeded from progress past the forward prong  86 . On the other hand, when the fork plate is rocked in a counterclockwise direction eighteen to twenty degrees, the forward prong is rotated out of its blocking position, but the rearward prong  88  moves into a blocking position with respect to the next ball  18 . Once the foremost ball has moved past the area of the fork, the fork plate  90  may be again rocked in a clockwise direction to allow the next ball  18  to roll into the foremost position against the forward prong  86 . 
     In the embodiment of FIGS. 1-4, one possible assembly for providing the fork rocking is illustrated. Referring primarily to FIG. 4, a connecting rod  104  has opposite ends that are attached by hind joints  106  and  108  to a lower lever  112  and an upper lever  110 . The tensioning of the connecting rod is adjusted by securing the lower hind joint  106  to any one of a series of holes  113 . Alternatively, the series of holes may be formed within the upper lever  110 . While the side view may cause it to appear otherwise, only a portion of the fork plate  90  is shown in the side views of FIGS. 1,  3  and  4 , since the upper lever  110  visually blocks all but the forward portion of the fork plate  90 . Referring briefly to FIG. 2, the upper lever  110  is coupled to the fork plate  90  by the fork shaft  102  that was described above. The fork shaft is rotatable, so that rotation of the upper lever  110  causes rotation of the fork plate  90 , and therefore angular displacement of the forward and rearward prongs  86  and  88 . 
     Returning to FIG. 4, the lower lever  112  rotates about a pivot point that is defined by a pawl shaft  114 . FIG. 4 shows the adjustable fork-and-actuator mechanism  116  in its rest position. This rest position is dictated by a spring member  118  and a stop  120  at opposite sides of the lower lever  112 . The spring member pulls an arm of the lower lever  112  to bias the lever for clockwise rotation. However, the stop  120  limits the extent to which the lever can rotate. Referring briefly to the side views of FIGS. 1 and 3, the spring member  118  is secured to the base  122  of the housing  12  by a cotter pin  124 . The stop  120  is fixed in position and is preferably an elastomeric member. 
     Again referring briefly to the top view of FIG. 2, the pawl shaft  114  is rotatably held in position at one end by a pawl bearing plate  126  and at the opposite end by a bearing plate  128  that supports the fork shaft  102  in addition to the pawl shaft  114 . A pawl  130  is clamped to the pawl shaft. Thus, force applied to the pawl will cause the fork-and-actuator mechanism  116  of FIG. 4 to be moved out of the rest position illustrated in FIG.  4 . The source of this applied force is a dog  132  that is connected to the motor-driven continuous chain described above. In the rest positions of FIGS. 1 and 4, the dog  132  is out of contact with the pawl  130 . However, in FIG. 3, the rotation of the continuous chain has caused the dog  132  to contact the pawl  130 . The continued motion of the dog  132  displaces the pawl to rotate about the shaft  114  on which it is mounted. The rotation of the shaft is transferred to the lower lever  112 , overcoming the bias of the spring member  118 . As a result of the counterclockwise rotation of the lower lever, the connector rod  104  pulls the upper lever  110  downwardly. The counterclockwise rotation of the upper lever  110  is translated to the fork plate  90  via the fork shaft  102 . Consequently, the forward prong of the fork is moved upwardly to allow the foremost ball  16  to progress to the firing chamber  24 . Eventually, the dog  132  releases the contact with the pawl and the fork-and-actuator mechanism  116  returns to the rest position of FIG.  4 . The singulation process repeats when a second dog  134  comes into contact with the pawl  130 . The timing of the singulation process is a factor of the spacing between dogs and the drive speed of the chain. 
     The dogs  132  and  134  also determine the timing of the firing sequence for projecting the ball  14  from the firing chamber  24  of FIG.  1 . The ball rests on the projection belt  60  that is held in a taut condition by the coil spring  72  that is connected to the spring-loaded bearing member  68 . However, as the dog  132  moves forwardly from the position of FIG. 1, it will force the bearing member  68  forwardly within the slot  70 . As a consequence, the belt will relax and the ball  14  will be allowed to lower further into the firing chamber  24 . Then, as the dog rotates downwardly toward the pawl  130 , the spring-loaded bearing member  68  is released. The projection belt  60  is again returned to the taut condition by the bias of the coil spring  72 , propelling the ball from the firing chamber  24 . As described in the above-cited patent to Whitfield et al., the tension adjustment achieved by means of the external knob  74  varies the flight-determining factors of the projected ball. 
     Piecing the various operations together, the dog  132  interacts with the spring-loaded bearing member  68  to relax the projection belt  60 , but then releases the bearing member to fire the ball  14  as the coil spring  72  pulls the projection belt back to a taut condition. The firing chamber is then again ready to accept a ball. The foremost ball  16  of FIG. 1 is released when the forward fork prong  86  is raised by rocking of the fork plate  90 . The elevation of the forward prong  86  is triggered by interaction between the dog  132  and the pawl  130 . Simultaneous with the elevation of the forward prong  86 , the rearward prong  88  is lowered to impede travel of the next ball  18 . This condition is shown in FIG.  3 . The dog  132  contacts the pawl  130 , which is mounted to the pawl shaft  114 . Counterclockwise rotation of the pawl shaft pulls the connector rod  104  downwardly to rotate the upper lever  110  that is mounted at the end of the fork shaft  102  opposite to the fork plate  90 . That is, the counterclockwise rotation of the lower lever  112  is accompanied by counterclockwise rotation of both the upper lever  110  and the fork assembly. When the dog releases the pawl, the spring member  118  returns the levers and the fork assembly to the rest position of FIGS. 1 and 4, so that only one ball is allowed to progress to the firing chamber. 
     The balls  14 - 22  of FIG. 1 may be softballs having regulation 12-inch circumferences. In order to change the apparatus  10  for use with a different-sized ball, the fork assembly may be changed and the length of the connector rod  104  may be adjusted. In the preferred embodiment, the apparatus includes a set of alternative fork assemblies. Referring to FIG. 7, a two-piece set of fork assemblies  136  and  138  is shown. The fork assembly  136  may be the original assembly for use with the 12-inch softballs, while the smaller fork assembly  138  may be dimensioned for use with regulation hard balls or with tennis balls. In the same manner as the original fork assembly, the smaller fork assembly  138  includes a fork plate  140  and a pair of cantilevered prongs  142  and  144 . Regarding the adjustment to the length of the connector rod of FIG. 1, the shortening of the connector rod will vary the distance of angular displacement. 
     The invention is best suited for periodically projecting a spherical ball, such as a tennis ball, baseball or softball. However, because the projecting belt  60  conforms to the dimensions of the ball, the invention may be used to toss American footballs, if the ball-supply path is configured to maintain the necessary rolling orientation of the footballs past the appropriate fork assembly. Moreover, the ball singulation process may be used in other applications.