Many different types of apparatus have been devised for exercising the human body. A teeter-totter, also known as a seesaw, is a well-known children's play apparatus. It consists of an elongated board that is balanced at about its longitudinal center on a fulcrum, which is typically a saw-horse. Two children then sit on opposite ends of the board facing each other. If the heavier child raises his or her feet above the ground, his or her end of the board will go down and the other end of the board will then lift the other child up into the air. Balance of the board can also be changed by sliding it longitudinally on the fulcrum.
In addition to walking and performing various other tasks and exercises, a person who wants to remain healthy will also need to be able to reliably maintain his or her balance, dynamically as well as statically. Balance board assemblies provide for this type of exercise. A balance board assembly includes an elongated board that is balanced at about its longitudinal center on a fulcrum, and the length of the board is such that a person using the apparatus for exercise can straddle the fulcrum with their two feet on respective ends of the board at the same time. The person will then face in a direction perpendicular to the longitudinal axis of the board.
Some balance board assemblies utilize non-motorized supports to provide a movable fulcrum; that is, a fulcrum which is capable of rolling or twisting on a supporting surface so as to move the position of the board itself relative to that supporting surface. Assemblies of this type are shown in U.S. Pat. No. 5,897,474 to Romero in which the fulcrum is provided by a semi-flexible ball; Collins U.S. Pat. No. 6,017,297 which shows an elliptical type roller supporting the board for allowing the board to move with respect to ground; and U.S. Pat. No. 5,125,880 to Peters, where the fulcrum for the board includes a differential drive mechanism that permits the board to be twisted in the horizontal plane. Since in all three of those patents the movable support is non-motorized, the user must then move his or her body in order to move his or her center of gravity to drive the movements of the apparatus.
Nelson U.S. Pat. No. 6,848,527 shows a motorized board that can be driven in a forward direction only, along the longitudinal axis of the board; hence it should be categorized as a skate board, not a balance board. Endo U.S. Pat. No. 5,487,441 also shows a powered skate board. Stevenson U.S. Pat. No. 3,224,785 likewise shows a skate board device that can be powered for motion in a forward direction.
The Bouvet U.S. Pat. No. 7,172,004 shows a non-motorized self-propelled skate board in which energy provided by the user first winds a band affixed to a drum, so as to thereafter provide driving power for moving the board in a direction along its longitudinal axis. Bouvet does not show an independent source of energy for moving the board.