U.S. Pat. No. 7,364,096 to Sosnowski et al., which is assigned to The Toro Company, the assignee of this invention, discloses a sprayer for applying a liquid, such as a fertilizer, insecticide or herbicide, to a turf surface. The sprayer includes a fixed center boom and a pair of pivotal wing booms that carry spaced spray nozzles along their lengths. In a spray position, the center and wing booms are substantially horizontal and aligned end-to-end along a substantially straight lateral axis with respect to the vehicle that carries the spray booms. In a transport position, the wing booms are folded upwardly and inwardly relative to the center boom until the wing booms become disposed in an X-shaped orientation when they reach the transport position.
Sprayers of this type apply a liquid to relatively large areas of ground or turf surfaces. The operator typically drives the vehicle carrying the spray booms back and forth in a plurality of side-by-side passes over the surface being sprayed. Usually, adjacent passes are driven in opposite directions, the operator making a first pass in one direction, then turning around at the end of the pass, making a second adjacent pass in the opposite direction, and then repeating this back and forth pattern of passes over the entire area of the surface being sprayed. In doing this, the vehicle should be driven as straight as possible so that the swaths of sprayed surface in each pass are aligned with one another as precisely as possible. In other words, the edge of a sprayed swath should match or mate to the nearest edge of the previous sprayed swath so that the entire surface is uniformly sprayed with no parts of the surface being missed by the spray and no parts of the surface being sprayed twice.
However, this is quite difficult for an operator to do. While automatic steering systems are known for controlling the path of a vehicle, such steering systems are quite expensive to use on the types of vehicles, such as vehicles like the Toro Workman® or the Toro Multi-Pro®, which are used as sprayer transport platforms. In addition, most supervisors of the operators of sprayers wish to encourage the operator to keep his or her hands on the steering wheel at all times and to be actively engaged in the operation of the vehicle. Vehicle automatic steering systems are somewhat inconsistent with this goal as they can induce the operator to unduly rely on the steering control provided by the automatic steering system.
One way that operators have attempted to prevent double spraying along the edge of a previously sprayed swath is to try and slightly overlap the edge of the next swath with the previous swath and to manually turn off the nozzle on the sprayer that is closest to the overlapped edge. However, this requires that the operator judge and precisely maintain the right amount of overlap. Despite the use of this technique, there are still areas of the surface that will miss being sprayed when the overlap is too small and that may be sprayed twice if the overlap is allowed to become too large. Moreover, this technique decreases productivity since putting down a swath that is purposely not as large as it could be by turning off the nozzle nearest the edge means that more passes of the vehicle will be necessary to spray a surface of a given size. Such productivity decreases are disadvantageous.
Accordingly, it would be an advance in the sprayer art to provide a sprayer having the ability to precisely apply the spray to a desired surface area to avoid missed or skipped areas and overlapped areas without use of an automatic steering system on the vehicle while maintaining maximum operator productivity.