| 摘要 |
A toy submarine consisting of three components. Two of the components are an injection molded thermoplastic and the other is an ordinary rubber band. The plastic is slightly positively buoyant in typical tap water. The first molded component is the tailpiece and it includes a generally cylindrical body with an integrated propeller. The second molded component is the headpiece and it includes a generally cylindrical body with an integrated propeller that spirals in the opposite direction of the tailpiece propeller. Together they form a counter rotating propeller system. The bodies of both the tailpiece and the headpiece are hollow and open at both ends. One end of the tailpiece's body mates with one end of the headpiece's body such that their axes are aligned and the bodies are able to easily rotate relative to each other. The other ends of the tailpiece and headpiece each have a longitudinal slot. In the assembly, the rubber band is routed through the slot and around the body of the tail piece, then routed through both bodies of the tail and head pieces, and then through the slot and around the body of the head piece. To use the toy submarine, the child holds either the tail piece or the head piece and, using a finger, rotates the other propeller until the rubber band is sufficiently twisted. Then the toy submarine is placed under water and released. The two propellers will begin rotate in opposite directions. It will quickly travel in a relatively straight line in a forward direction until the energy in the rubber band has dissipated. Then, because the plastic that was used for molding the two components is slightly positively buoyant, the toy submarine will slowly surface. |
