Abstract: An irrigation system is moved with an oscillating trojan bar operating against a lugged wheel. A drive pawl on the trojan bar drives the wheel forward on level ground or uphill. A hold-back pawl on the trojan bar keeps the wheel from running free when going downhill. The detent likewise contains an uphill pawl and a downhill pawl.

Abstract: An agricultural irrigation system has two reciprocating cables which are reciprocated at a main pivot and connected by chain and sprocket at the far end. Alternate vehicles are attached to one or the other cables. At each vehicle the cable acts to both align the vehicle and power it through a "joy stick" attached. Reciprocating motion of the "joy stick" powers the vehicle and tilting motion aligns it. The alignment is accomplished by lifting the dog from a ratchet wheel.

Abstract: A pivot or circle type irrigation system has a single hydraulic cylinder upon each vehicle to provide motive force to that vehicle. Two hydraulic tubes extend the length of the system and each hydraulic tube is connected to one side of each cylinder without valves. The cylinder movement is blocked if the vehicle upon which it is mounted is detected to be ahead by an alignment system. Hydraulic fluid is pumped into one tube until an increase of pressure indicates that all of the cylinders are cockablock and then the tubes are reversed and hydraulic fluid is pumped into the other line until, again, a rise in pressure indicates that all of the cylinders are cockablock.