| 摘要 |
A reversible self-propelled center pivot sprinkler system for sprinkling or irrigating a relatively large area surrounding a central pivot comprising an overhead water supply pipe extending outwardly from the center pivot point and supported by a plurality of spaced-apart, wheeled towers. A drive apparatus is provided on each of the towers to propel the towers and water supply pipe around the central pivot point. A control apparatus is provided on each of the towers for selectively operating the drive apparatus associated therewith to maintain the pipe and towers in an aligned condition as the water supply pipe is pivoted around the center pivot point. The drive apparatus is connected to a trojan bar which is reciprocatably mounted on the tower and which is provided with a selectively movable double dog on at least one end thereof for engagement with drive lugs on at least one of the drive wheels of the tower. The double dog is normally in position so that movement of the trojan bar in one direction will cause the dog to engage the wheel drive lugs so that the tower will be moved in a forwardly direction. The double dog may be selectively moved to a second position so that the dog will engage the wheel drive lugs as the trojan bar is moving in a second direction to cause the tower to be moved rearwardly. In one form of the double dog, the double dog is automatically controlled through the use of a pair of power cylinders. A modified form of the double dog permits the double dog to be manually moved between its forward and reverse modes. A still further modified form of the double dog comprises a hydraulic cylinder operatively connected to a reversible trojan bar dog having opposing dog surfaces. A double ratchet-type brake is provided on the tower to prevent the tower from undesirable rolling in a direction opposite to the direction of driving travel. The double ratchet-type brake may be operatively interconnected to the double dog whereby remote control or operation of the double dog also causes the double ratchet-type brake to be moved to permit to the direction of driving travel. The double ratchet-type brake may be operatively interconnected to the double dog whereby remote control or operation of the double dog also causes the double ratchet-type brake to be moved to permit the tower to roll in the desired direction while preventing undesirable rolling in the opposite direction. |
