A pinball game challenges a player to keep a ball in rolling motion on an inclined playfield for as long as possible. The playfield contains various contact points which, when struck by a rolling ball, award points to the player. In the simplest versions of pinball the player has some control over the motion of the ball by causing the playfield to move slightly just at the time the ball is making contact with one of the contact points. The player is therefore able to impart momentum to the ball in a direction over which he has some control. On the other hand, the ball when left to its own devices will ultimately roll into an exit path where the ball is directed to the lowest level of the playfield, at which point it will exit from the game. Persons familiar with pinball will appreciate that the game challenges a player to keep the ball out of the playfield's exit paths. Such persons will be aware of the moment of panic that occurs when the ultimate challenge has not been met and another ball is lost.
In more sophisticated versions of pinball additional means may be provided to the player to enable him to keep the ball out of the exit paths. For example, in one well-known version of a pinball game there are flippers placed on the playfield just above an entrance to an exit hole, or out-hole, at the bottom of the playfield. A player can activate the flippers by pushing a button available to him. If the flippers are activated when the ball is within the range of the flippers then substantial momentum may be imparted to the ball, propelling it upward on the playfield to a position comparable to the position the ball had at the beginning of play. A player with skill and coordination can use the flippers to prolong substantially the play of a game and postpone the inevitable moment of panic when the ball finally escapes through an exit passage. Play will not be indefinitely prolonged, however, because the ball may pass directly through a space provided between the flippers which is out of reach of either flipper so that no contact can be made between flippers and ball. Alternatively the ball may pass out of play through a different exit passage which is not guarded by flippers.
Another means for prolonging the play of a pinball game is exemplified by Frank T. Murphy, Norman R. Clark, and William E. Casey U.S. Pat. No. 3,578,802. Murphy, et al. provide raisable bumpers, or contact points as previously described, which are normally flush with the surface of the playfield. The player is provided with buttons which will cause specified bumpers to rise vertically above the surface of the playfield to a position where they can be struck by the ball. The raisable bumpers may be placed at entrances to exit paths so that the skillful activation by a player will prevent a ball from entering the exit path. The raisable bumper, however, lacks a desirable feature of flippers in that the bumper carries no momentum of its own that can be imparted to the ball. That is, a flipper functions dynamically and is capable of returning a ball to an initial position at the top of a playfield regardless of the ball's momentum when impacted by the flipper. The raisable bumper, on the other hand, will only return the ball to a height dependent upon the ball's momentum at the time of striking the bumper.