Patent ID: 6293475
Filing Date: 2001-09-25
Classification: A01M

Abstract:
An agricultural sprayer that travels in a forward direction during normal spraying operations, the sprayer comprising:a tank for holding a product desired to be sprayed;a boom on which are mounted a plurality of sprayers for dispensing the product from the tank, the boom including an inner piece positioned adjacent to the tank and an outer piece positioned away from the tank, the inner and outer pieces being foldably connected to one another at a pivot region which allows the inner and outer pieces to be pivoted between a folded orientation and an extended orientation;a hydraulic cylinder for hydraulically pivoting the inner and outer pieces of the boom between the folded orientation and the extended orientation, the hydraulic cylinder including a piston structure connected to one of the inner and outer pieces of the boom and a cylinder portion connected to the other of the inner and outer pieces of the boom, the piston structure of the hydraulic cylinder including a piston head connected to a piston rod, and the cylinder portion defining a first port located on a first side of the piston head and a second port located on a second side of the piston head;a pressure source for providing hydraulic pressure to the hydraulic cylinder for pivoting the inner and outer pieces of the boom between the extended and folded orientations by causing the hydraulic cylinder to extend or retract;a hydraulic control system for controlling the operation of the hydraulic cylinder, the hydraulic control system being operable in an unfold mode in which hydraulic pressure from the pressure source causes the hydraulic cylinder to pivot the outer piece of the boom from the folded orientation to the extended orientation and a fold mode in which hydraulic pressure from the pressure source causes the hydraulic cylinder to pivot the outer piece of the boom from the extended orientation to the folded orientation, the hydraulic control system also being operable in a neutral mode in which the pressure source is prevented from extending or retracting the hydraulic cylinder; andthe hydraulic control system including a hydraulic circuit relative axial movement between the piston structure and cylinder portion of the hydraulic having a flow line that provides fluid communication between the first and second ports of the cylinder portion when the hydraulic control system is operating in the neutral mode;the hydraulic control system including an accumulator for: a) accumulating hydraulic fluid under pressure when the outer boom piece collides with an obstruction and is pivoted rearwardly from the extended orientation toward the folded orientation; and b) forcing the pressurized hydraulic fluid from the accumulator back toward the hydraulic cylinder after the obstruction has been bypassed;the hydraulic control system including at least one valve for: a) blocking the flow line between the first and second ports and also blocking fluid communication between the accumulator and the hydraulic cylinder when the hydraulic control system is in either the fold mode or the unfold mode; and b) opening the flow line between the first and second ports and opening fluid communication between the hydraulic cylinder and the accumulator when the hydraulic control system is in the neutral mode;wherein the accumulator automatically causes the outer boom piece to return to the extended orientation after the obstacle has been bypassed by providing stored hydraulic pressure to the hydraulic cylinder which forces the hydraulic cylinder to pivot the outer boom piece in the forward direction to the extended orientation.