U.S. Pat. No. 6,901,729 is incorporated herein by reference in its entirety. This patent describes a windrower. While other embodiments are possible, it is this general type of windrower that provides the best example of the type of system with which the apparatus and method of the instant invention can/should be used. Provisional Patent Application No. 60/699,944, filed Jul. 16, 2005, is also incorporated herein by reference in its entirety.
In any modern windrower, and much other similar equipment, it is important to efficient and effective operation that certain system components be calibrated so that outputs can be reasonably relied upon by the operator.
One such component is the forward-neutral-rearward (FNR) lever, also referred to and as the multi-function handle (MFH). The FNR lever or MFH is an operator controlled component located within the operator platform area or cab, and is manipulated by an operator for controlling propulsion direction and speed. The FNR lever has a neutral position, which is typically a straight up position, and is typically movable from the neutral position forwardly for inputting commands to the windrower propulsion system for effecting forward movements of the windrower, and is movable from the neutral position rearwardly for inputting commands for effecting rearward movements of the windrower. The FNR lever or MFH is an assembly of components, including a sensor device such as a potentiometer which outputs signals, such as a varying voltage to a propulsion system controller, the value of which signal or voltage is a function of the lever position. A suitable conductive path, such as a wiring harness or the like, is provided for communication of the signals. The FNR lever or MFH also typically includes a switch commonly referred to as the neutral safety switch or neutral switch, which is transitioned from one state to another state when the lever or MFH is moved to and from the neutral position. The state of this switch is also communicated to the propulsion system controller via a suitable conductive path, such as a wiring harness or the like.
Because the FNR lever or MFH is an assemblage of components, and is itself mounted in an assembly, it has been found that there will often be slight variations in output signals between different FNR levers or MFHs, and between different windrowers, such that it is desirable to calibrate the FNR lever or MFH initially before use, after service or replacement, and any time that a fault condition is evident, so as to ensure reliable, accurate outputs.
Additionally, the FNR lever or MFH, or the circuitry of the propulsion system can include devices such as electrical relays and the like, which can be subject to problems which may negatively effect or degrade the operation of the propulsion system or may be indicators of imminent failure of the device. For instance, at some FNR lever positions it may be desirable for a relay to latch for some predetermined time period, for purposes such as to allow for transitioning operating systems of the propulsion system to a new state. As an example, a system may include a propulsion enable relay which is a latching relay which remains latched for a short period after the FNR lever is moved from a propulsion position (forward or rearward) to the neutral position, to provide continued power for transitioning the propulsion mechanism from a propulsion state to the neutral state. It would thus be desirable to have a capability to reliably detect problems with such devices, as part of a calibration process or routine.
Therefore, what is sought is an apparatus and method for calibration of an FNR lever or MFH and detection of problems with related devices, to ensure reliable, accurate outputs therefrom.