| 摘要 |
A ball-launching system for a dog's ball which automatically launches or shoots a ball along an airborne path, thereby enabling the dog to chase the ball, fetch it and return it to the system. The system includes a ball collection area for receiving the returned ball, dropped or otherwise deposited therein by the dog, and for feeding the returned ball, under the force of gravity along, into the hollow interior of a ball-launching tube. As the ball rolls down the hollow interior of the tube, a sensing device detects the passage of the ball therover and generates a command signal. The command signal is delayed a predetermined period of time, sufficient to enable the ball to contact the rear end of the tube and come to rest in a firing position. A delayed signal is then used to energize a relay coil and operate a normally-open switching element disposed in a path between the source of electrical power and a solenoid coil for closing the relay-operated switches and energizing the solenoid coil to shift a piston-like solenoid rod from a cooked or withdrawn position to a forwardly-extended position in which the distal end of the rod extends through an aperture in the rear end of the tube and impacts a ball at rest in the firing position adjacent the closed end of the tube for firing or launching the ball up the hollow interior of the tube, out of the open mouth and on an airborne trajectory to again be chased, fetched and returned by a dog to begin the cycle anew.
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