Abstract:
A plaything for executing a reciprocating activity has a curved platform reciprocatably mounted on a base. The platform has a traveling surface with a longitudinally spaced, opposing pair of end ramps. A coaster can travel back and forth freely on the platform. The end ramps are inclined to cause reversion of the coaster.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to playthings for executing a reciprocating activity, and in particular, to playthings with a traveling coaster. 
   2. Description of Related Art 
   Skateboarders accomplish remarkable athletic feats by traversing the opposing banks or ramps of a half pipe, using the banks to reverse their direction of traversal. Using a similar structure snowboarders and BMX bikers perform comparable athletic feats by riding from one bank to an opposite bank, again reversing direction at the peak of travel. 
   In U.S. Pat. No. 6,350,174 a miniature roll-up half-pipe is used with a miniature fingerboard 60. The user places a finger on the upper surface of the fingerboard 60 and rolls it back and forth along flexible sheet 35, manipulating it to perform typical skateboard stunts. 
   In U.S. Design Pat. 487,486 a toy road racing skateboard has a miniature rider mounted on top. 
   In U.S. Pat. No. 6,540,577 a fingerboard contains magnetic material, and can be manipulated to perform typical skateboard tricks using a finger ring 30 or fully poseable action figure 50. 
   In U.S. Pat. No. 6,742,780 a skateboard maze has a board with grooves on its topside forming the maze. The grooves are deep enough to hold a ball. The user stands on top of the board and rocks it back and forth, causing the ball to move through the maze. 
   In U.S. Pat. No. 2,433,995 an electromagnet 6 is controlled by switches 13 and 14. The user opens and closes the circuit to cause a metal ball to roll towards target 9 mounted in a spherical bowl. 
   In U.S. Pat. No. 4,055,341 a maze is provided in platforms 22 and 24. The user stands on a textured traction surface 46 and rocks the platforms to move a ball toward a goal at the end of the maze. 
   In U.S. Pat. No. 4,681,320 a top spins on a hinged game board. The user can move the game board to steer the top on spiral path 18 from a start to a finish point. 
   In U.S. Pat. No. 4,394,961 jumping-off ramp 1 and jumping-on ramp 2 are arranged opposite one another on two track sections. A toy vehicle 4 leaves ramp 1 at an angle that can be adjusted using handle 1c. 
   In U.S. Pat. No. 6,726,523 a remote controlled toy skateboard device includes a toy figure mounted on a skateboard. The speed and direction of travel for the device is controlled by a portable remote control unit. 
   In U.S. Pat. No. 6,776,685 a collapsible toy vehicle ramp has a flexible panel, used as a jumping surface. The ramp is designed to collapse under weight exceeding the normal weight for a toy vehicle. 
   In U.S. Pat. No. 6,623,367 a fingerboard ramp includes at the intersection of sections 36 and 38 an edge coping 44 made of metal tubing. See also U.S. Pat. Nos. 4,251,949; and 5,409,223. 
   Accordingly, there is in need for a plaything that allows a player to execute a reciprocating activity, especially an activity where a coaster travels up an inclined ramp before reversing direction and traveling towards an opposite ramp. 
   SUMMARY OF THE INVENTION 
   In accordance with the illustrative embodiments demonstrating features and advantages of the present invention, there is provided a plaything for executing a reciprocating activity. The plaything has a curved platform reciprocatably mounted on a base. The platform has a traveling surface with a longitudinally spaced, opposing pair of end ramps. A coaster can travel back and forth freely on the traveling surface. The end ramps are inclined to cause reversion of the coaster. 
   In accordance with another aspect of the invention a method is provided for playing with a coaster on a curved platform having a traveling surface with a longitudinally spaced, opposing pair of end ramps. The method includes the step of placing the coaster on the traveling surface. Another step is reciprocating the platform longitudinally to cause the coaster to travel back and forth freely on the platform between the end ramps. The reciprocation is timed to cause periodic reversion of the coaster after arrival at each of the end ramps. 
   In accordance with still another aspect of the invention a plaything is provided for executing a reciprocating activity. The plaything includes a curved platform having a traveling surface with a longitudinally spaced, opposing pair of end ramps. Also included is a coaster for traveling back and forth freely on the traveling surface. The end ramps are inclined to cause reversion of the coaster. The platform is manually reciprocatable to cause the coaster to travel back and forth between the ramps. 
   By employing structure and methods of the foregoing type, an improved plaything and play activity is achieved. In one embodiment, a coaster in the form of a wheeled carriage travels back and forth on a movable platform between opposing inclined ramps. In this embodiment, the platform is reciprocated by a player to cause the coaster to travel between the inclined ramps, reversing direction at the peak of its travel on the ramps. The coaster can be designed to look like a miniature skateboarder, biker, snowboarder, automobile, skier, etc. 
   The player can reciprocate the platform longitudinally (i.e., moving the ramps anteriorly and posteriorly) to propel the coaster between the ramps. The player can also twist the platform or move it transversely to steer the coaster. In this fashion a skillful player can turn the coaster on the ramps so it keeps traveling nose first. 
   In one embodiment the platform rolls on ball bearings on the top of a base. The base may have manual controls in the form of a pair of joysticks rotatably mounted by ball and socket joints at a control panel on the base. The joysticks each have an internal proximal shaft that links to a plate that is attached to the bottom of the platform. Thus by operating the joysticks the player can translate the platform in two dimensions (i.e., longitudinally and transversely). Also, by moving the joysticks differentially, the player can rotate the platform about a vertical axis. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above brief description as well as other objects, features and advantages of the present invention will be more fully appreciated by reference to the following detailed description of presently preferred but nonetheless illustrative embodiments in accordance with the present invention when taken in conjunction with the accompanying drawings, wherein: 
       FIG. 1  is a perspective view of a plaything in accordance with principles of present invention; 
       FIG. 2  is a front elevational view of the plaything of  FIG. 1 ; 
       FIG. 3  is a side elevational view, in cross-section, of the plaything of  FIG. 1 ; 
       FIG. 4  is a detailed, sectional view of one of the rollers of the platform of  FIGS. 1-3 ; 
       FIG. 5  is a detailed view, partly in section, of the joint between the platform and the plate of  FIG. 3 ; 
       FIG. 6  is a bottom view of the platform of  FIG. 1 ; 
       FIG. 7  is a perspective view of the plate of  FIG. 3 ; 
       FIG. 8  is a top view of the base of  FIG. 1  with the platform removed; 
       FIG. 9  is a detailed view, partly in section, of one of the manual controls on the base of  FIG. 1 ; 
       FIG. 10  is an elevational view of the coaster of  FIG. 1 ; 
       FIG. 11  is a detailed view of one of the journals of the coaster of  FIG. 10 ; 
       FIG. 12  is a sectional, side elevational view of a portion of a plaything that is an alternate that described above; and 
       FIG. 13  is a detailed perspective view of the knuckle joint shown in  FIG. 12 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to  FIGS. 1-6 , the illustrated plaything has a platform  10  with a traveling surface  12  that extends longitudinally into an opposing pair of end ramps  14 . The upper portions  14 A of ramps  14  are almost vertical and in some embodiments may actually curl into an overhang. The platform  12  is gutter-like and is intended to simulate in miniature the half pipe that might be used by a skateboarder, BMX biker, snowboarder etc. The outside faces  10 A of platform  10  are inclined and diverge outwardly. In one embodiment platform  10  has an overall length of 20 inches (51 cm), a transverse width of 14 inches (36 cm) and an overall height of five inches (13 cm) although these dimensions can be different in other embodiments. Platform  10  may be injection molded plastic, but in some embodiments may be a sheet metal stamping, ceramic molding, metal casting, wood carving, etc. 
   In this embodiment traveling surface  12  is shown curved along a central, ramp-to-ramp travel path  62 , but not curved in a transverse direction; for example, not curved in the transverse direction of transverse centerline  64 . In other embodiments most of the traveling surface  12  can be bowl-shaped, that is, concave in both a transverse direction T and a ramp-to-ramp direction  62 . Such a bowl shape tends to bring coaster  52  toward the central travel path  62 , thereby preventing the coaster from falling off traveling surface  12 . Instead of using a bowl shape, some embodiments may keep coaster  52  in play by installing a fence (not shown) along the edges  12 A of surface  12 . 
   The underside of platform  10  has a rectangular recess  16  that is lined with metal sheet  27 , which may be glued in place. Attached in the corners of recess  16  are four subjacent rollers  19 , shown in  FIG. 4  as ball bearing  18  mounted in socket  20  and captured by annular cap  22 , which may be attached by screws, threads, or the like.  FIGS. 2 and 3  show rollers  19  rolling on topside  24  of a base  26 . Base  26  is a substantially rectangular casing with its upper front corner beveled to form a control panel  28 . In one embodiment the overall dimensions of base  26  are 24″×18″×5″ (61 cm×46 cm×13 cm) although these dimensions can be different in other embodiments. Base  26  may be made of plastic, metal, ceramic, etc. In some embodiments base  26  may have a pair of carrying handles for transporting the plaything. 
   Bores  30  on the underside of platform  10  align with matching holes in metal sheet  27  and are designed to each receive self tapping screw  32  ( FIG. 5 ). Screw  32  is inserted through a hole in plate  34  and the bushing  36  before being threaded into bore  30 . Accordingly, plate  34  is attached to the underside of platform  10  and stands off by the distance determined by bushing  36 . 
   Referring to  FIGS. 7 and 8 , screws  32  in plate  34  project through a central hole  38  in the topside  24  of base  26 . Plate  34  is shown as a stepped structure with an upper plateau  34 A, a riser  34 B, and a lower plateau  34 C. 
   Referring again to  FIGS. 1-6  and also to  FIG. 9 , plate  34  is shown inside base  26 , attached to the underside of platform  10  and reaching forwardly to a position below the control panel  28 . A pair of manual controls  38  are shown projecting through control panel  28 . In this embodiment controls  38  are a pair of joysticks with a spherical handle  40  molded on the upper end of a metal rod  42 . A plastic ball  44  is molded around rod  42  to divide the rod into an external distal shaft  42 A and a proximal internal shaft  42 B. Ball  44  is rotatably mounted in a socket  46  that is attached to the underside of control panel  28  in alignment with hole  48 . Accordingly, joysticks  38  can tilt in the two directions  50  ( FIG. 1 ), giving the axes of each of the joysticks  38  two rotational degrees of freedom. 
   Proximal shaft  42 B can likewise move with two degrees of freedom. Proximal shaft  42 B is shown coupled to plate  34  by insertion through its hole  50 , which is rimmed with a plastic grommet  52 . Secured to the end of proximal shaft  42 B is a hat-shaped cap  54  locked in place by internal barbs (not shown) and designed to prevent shaft  42 B from disengaging plate  34 . 
   Referring to  FIGS. 1 ,  10  and  11 , a coaster  52  is shown as a carriage  54  with a plurality of wheels  56  made of an elastomer such as neoprene. Wheels  56  are mounted in pairs on the ends of two separate axles  58 . Each axles  58  is mounted in a pair of journals, one such journal  60  being shown in  FIG. 11 . Specifically, shaft  58  is downwardly biased by compression spring  62  to give the shafts and wheels  56  some ability to absorb jolts. 
   In this embodiment, carriage  54  is shaped like a miniature skateboard. In some embodiments an optional miniature skateboarder  58  can be mounted atop board  54 . Skateboarder  58  may be a molded plastic figure or simply a cardboard cutout fitted into a slot atop board  54 . The coaster  52  is designed with a low center of gravity and a weight of about 3-5 ounces (86-143 grams). This weight can be accomplished by casting board  54  in metal or by fitting a plastic board with metal weights. 
   In other embodiments board  54  may be shaped like a snowboard and can be fitted with a miniature snowboarder. In still other embodiments the coaster may be made in the shape of a BMX bicycle with a rider. This bicycle can ride on its two wheels and be stabilized by wheels on outriggers similar to training wheels used on children&#39;s bicycles. Alternatively, the coaster can be in the form of a miniature automobile, a skier, etc. In the simplest embodiments, the coaster may be a ball or marble. 
   Referring to the alternate embodiment of  FIGS. 12 and 13 , components corresponding to those previously illustrated bear the same reference numeral but increased by 100. In particular, base  126  is a hollow case with a horizontal topside  124  and a slanted control panel  128 . 
   In this embodiment controls  138  are again a pair of joysticks, each with a spherical handle  140  molded on the upper end of a metal rod  142 . A plastic ball  144  is molded around rod  142  and is rotatably mounted in a socket  146  that is attached to the underside of control panel  128 . A proximal portion  142 B of rod  142  is connected through a knuckle joint to the distal end of rod  166 . This knuckle joint is accomplished by terminating rod  142 B in an eye  142 C that is linked through an eye  166 A in the distal end of rod  166 . 
   Plastic ball  168  is molded around rod  166  and is rotatably mounted in a socket  170  that is attached atop a slanted panel  172 . Panel  172  is supported by a vertical wall  174  and horizontal wall  176 , which are each attached to the interior of base  126 . The proximal portion  166 B of rod  166  passes through a hole, in panel  172  and a grommet  152  mounted in a hole in plate  134 . Plate  134  is bolted to previously mentioned platform  10 . 
   The foregoing linkage alters the response of plate  134  to movement of joystick  138 . If joystick  138  is pushed away from the user from position P 1  to position P 2 , eye  166 B swings down so that proximal portion  166 B of rod  166  swings up from position P 1 ′ to position P 2 ′. Consequently, moving joystick  138  away from the user will also cause plate  134  and the platform  10  ( FIG. 1 ) to move away from the user. Also, pulling joystick  138  toward the user will move plate  134  and the platform toward the user as well. Similarly, swinging joystick  138  to the right (left) will cause plate  134  and the attached platform to shift to the right (left). It will be noted that eyes  142 C and  166 A forming the knuckle joint are loosely linked to accommodate the tendency of the eyes to separate when swung to an extreme position. 
   To facilitate an understanding of the principles associated with the foregoing apparatus, the operation of the embodiment of  FIGS. 1-10  will be briefly described. Case  26  may be placed on a level surface and the player may grasp the two joysticks  38 , one with each hand. Starting with the joysticks  38  in the neutral positions illustrated in  FIGS. 1-3  the player may synchronously swing both joysticks  38  to the right (left). Consequently, proximal shafts  42 B will both move to the left (right), thereby causing plate  34  to also move to the left (right). Since it is attached to platform  10  by screws  32 , platform  10  will also move in the same direction as plate  34  (i.e., longitudinally) as the rollers  19  roll across topside  24 . It will be appreciated that as the proximal shafts  42 B swing they will also slide in and out of holes  50 , with binding being avoided by friction-reducing grommets  52 . It will be further noted that platform  10  and distal shafts  42 A of the joysticks  38  move in opposite directions. Thus a rightward motion of the top of the joysticks  38  produces a leftward motion of the platform  10 . 
   The player may instead synchronously grasp and swing both joysticks  38  up (down). Consequently, proximal shafts  42 B will both move down (up), thereby causing plate  34  to move toward (away from) control panel  28 . Since it is attached to plate  34  by screws  32 , platform  10  will also move in the same direction as plate  34  (i.e., transversely) as the rollers  19  roll across topside  24 . The motion of platform  10  will be reactive to motion of joysticks  38  in that upward (downward) motion of the tops of joysticks  38  brings platform  10  toward (away from) control panel  28 . 
   The foregoing showed platform  10  being translated purely longitudinally (direction L), and then purely transversely (direction T). The player can also synchronously move the joysticks  38  obliquely, e.g., with components of upward and rightward motion. In circumstances where these components are equal, the center of platform  10  will move to the left and toward control panel  28  at 45° relative to the front of case  26 . In this fashion the player can translate the center of platform  10  in any desired azimuthal direction. 
   In the foregoing cases joysticks  38  were always moved synchronously in the same direction so that platform  10  did not rotate. In some cases the player may keep one joystick  38  stationary and swing the other. In this case, the plate  34  will rotate about one of its holes  50 . Consequently, the center of platform  10  will follow an arcuate path with two components of motion, that is, will follow a path with a with the changing balance of longitudinal component L and transverse component T. For example, if the left one of the joysticks  38  is stationary, lifting the other joystick  38  will cause platform  10  to rotate clockwise with the angular acceleration forces of this rotation greater at the right one of the ramps  14 . 
   Note certain joystick motions are not possible such as swinging one of the joysticks  38  to the right while the other is swung to the left. In some instances, however, one of the joysticks  38  will be lifted up while the other one will be pulled down. In that case, starting from the illustrated neutral position, the center of platform  10  will translate along an arcuate path. Platform  10  will rotate as well, with the angular acceleration forces of this rotation being balanced between the right and left one of the ramps  14 . 
   It is also possible to rotate platform  10  about some center of rotation without translating that center. For example, platform  10  can be rotated clockwise by moving the left one of the joysticks  38  up and to the left, while moving the right one down and to the left. 
   It will be appreciated that various combinations of joystick movements can cause complex motions of platform  10 . In any event the two joysticks  38  can be moved synchronously in the same direction with two degrees of freedom. In this specification coordinates were described where one degree of freedom was defined as an up-and-down motion and the other degree was defined as a right-left motion, although other coordinate systems can be declared. 
   The foregoing dual joystick system can be considered as sharing a third degree of freedom associated with the rotation of platform  10 . For example, the joysticks  38  can be manipulated to rotate platform  10  about its center before moving joysticks  38  in the same direction to accomplish two-dimensional translation of the platform. Therefore, the position of platform  10  can be defined by locating its center within a predetermined circular domain and by also defining its azimuthal orientation. It will be appreciated that opening  38  in the topside  24  of base  26  is dimensioned to accommodate the permissible placements of platform  10 . 
   Play can be started by placing coaster  52  on one of the ramps  14  and allowing the coaster to travel down that ramp to the other. If nothing further is done coaster  52  will oscillate back and forth a few times before coming to rest in the center of traveling surface  12 . Instead, however the player will move joysticks  38  right and left to harmonically reinforce the oscillation of coaster  52 . Using joysticks  38  the player can move the platform to the right as the coaster  52  climbs the left one of the ramps  14  thereby adding kinetic and potential energy to the coaster  52 . Eventually coaster  52  stops and reverses direction on the left one of the ramps  14  and travels towards the right one of the ramps  14 . Now the player can move the platform to the left to add kinetic and potential energy to the coaster  52 , before it stops and reverses direction to start another cycle. 
   In some cases the speed of coaster  52  is so high that it flies off the end of a ramp  14  to “catch air.” The player can then retract that ramp so that coaster  52  will reliably reengage the ramp. In some embodiments the lip of the ramps  14  will be formed into an overhanging curl so that coaster  52  rides into that curl and flips. 
   Also, the player may move joysticks differentially to impart a twisting motion to platform  10 . For example, as coaster  52  climbs one of the ramps  14  the player can move one of the joysticks  38  up while moving the other down to steer coaster  52  off the path  62 . If done properly, coaster  52  will ride up ramp  14  nose first, turn and then travel down the ramp nose first. If the player wishes to create additional angular acceleration forces to accomplish this turn one of the joysticks  38  is kept stationary while the other is moved in an up-down direction. For example the left joystick can be kept stationary when the coaster  52  is traveling the right one of the ramps  14 , allowing the right one of the joysticks  38  to impart more angular acceleration forces to that right ramp. 
   The embodiment of  FIGS. 11 and 12  will be played in a similar manner, except that motion of the joystick will produce a response that is the opposite of that just described. Once the player has is accustomed to this type of movement, the play will proceed in a manner similar to that just described. 
   It is appreciated that various modifications may be implemented with respect to the above described, preferred embodiments. In some embodiments the joysticks can be replaced with wheels, levers, sliders, foot petals, cranks, etc. For example in some embodiments, especially those with coasters shaped as miniature automobiles, the joysticks can be replaced with a steering wheel and gear shift lever (or foot pedal). The shift lever (or foot pedal) can be linked to the platform by bicycle cables that control the longitudinal reciprocation of the platform, while the steering wheel can rotate the platform to accomplish steering of the miniature automobiles. In general, the linkage of the platform to the manual controls can be accomplished by pulleys, chains, levers, gear trains, slides etc. In some embodiments the manual controls can be electronic and can include potentiometers, switches, strain gauges, etc. For such embodiments, the actuators controlling movement of the platform can be solenoids, stepper motors, etc. In other embodiments the electrical controls can operate electromechanical valves that in turn operate hydraulic actuators that move the platform. Alternatively, the manual controls themselves can be hydraulic and can include pistons for applying pressure to a hydraulic fluid. Furthermore, automated embodiments may be employed where the platform automatically reciprocates right and left at a frequency and amplitude appropriate for sustaining back and forth motion of the coaster. In such embodiments, the player can be given controls that enable small perturbations of this oscillation in order to allow the player some influence over the speed and direction of the coaster. In simplified embodiments, the manual controls can be eliminated and the player can directly grasp the platform and manually reciprocate it on the base. In even simpler embodiments, the base can be eliminated and the player can manually move the platform with it suspended in the air or rolling or sliding on a table or other working surface. In some embodiments the traveling surface of the platform may have shallow ruts that tend to guide the coaster along predetermined paths. While the previously described platform moves without changing elevation, in other embodiments the manual controls can rock the platform about a transverse axis so that one ramp rises while the other descends. Alternatively, rocking can be accomplished by allowing one ramp to vertically reciprocate and then remain at a constant elevation followed by an interval where the other ramp vertically reciprocates. As still another alternative, the platform can be rocked by vertically reciprocating only one of the ramps while the other ramp remains at a constant elevation. 
   Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.