Abstract: A hydraulic system that has a hydraulic pump connected to and in communication with a hydraulic motor, at least one hydraulic cylinder, or both by a first conduit and a second conduit (i.e., a high side and a low side). The hydraulic system has a bypass valve connected to and in communication with the first conduit and the second conduit. The bypass valve has a preset pressure that is above a minimum low side pressure. When a shock load occurs in the hydraulic system and a related drop in pressure on the low side occurs, the bypass valve opens when the preset pressure is passed thereby preventing the pressure from dropping to the minimum low side pressure. The hydraulic system thereby avoids a low loop event that could cause damage to the hydraulic system without the presence of larger charge pumps or accumulators.

Abstract: A hydraulic system that has a hydraulic pump connected to and in communication with a hydraulic motor, at least one hydraulic cylinder, or both by a first conduit and a second conduit (i.e., a high side and a low side). The hydraulic system has a bypass valve connected to and in communication with the first conduit and the second conduit. The bypass valve has a preset pressure that is above a minimum low side pressure. When a shock load occurs in the hydraulic system and a related drop in pressure on the low side occurs, the bypass valve opens when the preset pressure is passed thereby preventing the pressure from dropping to the minimum low side pressure. The hydraulic system thereby avoids a low loop event that could cause damage to the hydraulic system without the presence of larger charge pumps or accumulators.

Abstract: A power split transmission concept for two or three or four modes is provided with two variable hydrostatic units, an engine mechanically connected to the row 1 sun of a planetary gear set with at least two planetary rows, the second row of the planetary rows being connected to a row 2 sun, whereby both hydrostatic units stay connected with the same planetary element through all modes, one hydrostatic unit being connected to the sun of row 2 and the other hydrostatic unit being connected to a ring gear of planetary row 2.

Abstract: A vehicle having a frame with an engine mounted thereon. The engine has an output shaft that is connected to the input shaft of at least one hydromechanical transmission with a drive belt. A second hydromechanical transmission can then be used in association with the engine, first hydromechanical transmission and drive belt in order to provide an output to actuate driving elements in order to drive the vehicle.