Patent ID: 7204086
Filing Date: 2007-04-17
Classification: B66F,E02F

Abstract:
1. A method of operating a hydraulic system of a loader machine, the loader machine having a loader arm assembly connected to a body so that in a lowered position of the loader arm assembly, a working implement carried at an outer end of the loader arm assembly is disposed in front of the body, and which loader arm assembly is movable between raised and lowered positions by means of a hydraulic ram of the hydraulic system, the hydraulic system further including ride improvement system including a hydraulic accumulator which is connected to the hydraulic ram, a selection valve connected to each of a first and second chamber of the hydraulic ram, and a check valve assembly including a check valve, the check valve assembly connected between the first chamber and the selection valve such that the check valve, when in a closed condition, prevents fluid under pressure passing from the first chamber to the selection valve, and the check valve assembly having hydraulic fluid responsive means responsive to hydraulic fluid pressure in the second chamber to move the check valve assembly to an open condition, and there being means to connect the hydraulic fluid pressure in the second chamber to the check valve assembly, the method including: operating the selection valve to raise the loader arm assembly by feeding fluid under pressure to one chamber of the ram and to receive fluid at a lower pressure from the second chamber of the ram, or to lower the loader arm assembly by feeding fluid under pressure to the second chamber of the ram and to receive fluid at a lower pressure front the first chamber of the ram, and when the selection valve means is operated to raise and lower the loader arm assembly, allowing free two-way communication between the first chamber of the hydraulic ram and the accumulator during raising and lowering.