| 摘要 |
<p>A brake for an air-powered sprinkler system for preventing the drive towers from rolling down inclines and for preventing the wind from rolling the drive towers. An overhead water supply pipe extends outwardly from the center pivot point and is supported by a plurality of spaced apart wheeled drive towers. An air-powered drive mechanism is provided on each of the towers to propel the towers and water supply pipe around the center pivot point. A control mechanism is provided on each of the towers for selectively operating the drive mechanism associated therewith to maintain the pipe and towers in an aligned condition as the water supply pipe is pivoted around the central pivot point. The control mechanism comprises a rotary cam plate having an alignment rod secured thereto which extends to the gimbal ring on a flexible joint positioned on the water supply pipe adjacent the tower. The rotary cam plate controls the operation of a hydraulic cylinder which is pivotally connected to a trojan bar mounted on the drive tower for reciprocating movement. The trojan bar is provided with downwardly extendings dogs on its opposite ends which engage the drive wheels to rotate the same on actuation of the hydraulic cylinder. A brake is mounted on the drive tower and is urged into engagement with the inside of the drive wheel rim by a spring means to prevent undesirable rotation of the drive wheel. An air cyclinder is operatively connected to the brake to move the brake out of frictional engagement with the drive wheel rim as the trojan bar is driving the drive wheels.</p> |
