Steering Pilot Controller Disabling Circuit
Publication Date: 2017-Feb-17
The IP.com Prior Art Database
Title: Steering Pilot Controller Disabling Circuit
Brief Description of the Drawings: Figure 1 is a circuit diagram illustration of a preferred embodiment of this disclosure.
Description: As shown in the attached illustration and described below, a circuit configuration of a steering
system that disables the steering function based on armrest position, is disclosed.
Various forms of steering system interfaces exist in the construction and industrial equipment market, some with and some without steering wheels. In some cases, it is desirable to design a system without a steering wheel to improve visibility and reduce the clutter in the vehicle operator station. Often times, a lever (or joystick) is included on either the right or left side of the operator seat for controlling steering. With such a lever, considerations need to be made such that the armrest containing it can be lifted out of the way to make space for proper ingress/egress.
In such a system, it is often required to include a mechanism that in some way disables the steering function when the lever is lifted out of the way. In a fully hydraulic system (without any software control logic), this can be achieved by utilizing a valve that blocks pilot pressure from engaging the control lever. Considerations often need to be taken in this arrangement to protect the steering system from disabling due to a single point fault.
This disclosure describes a circuit containing two armrest position switches and one steering pressure switch that are used to energize two separate pilot pressure control solenoids. In this system, the two armrest position switches each control one of the two pilot pressure control solenoids, designed in a parallel configuration. In series with that portion of the circuit is the steering pressure switch, which connects the entire circuit to an un‐switched power source (such as a vehicle battery) when pressure is applied. Pressure can be referenced from a number of locations, including the steering system (pump) pressure or the steering pilot pressure. The steering system in this case is disabled only if both solenoids are powered through this circuit. The attached figure is a ...