COMPONENT OPERTATION / Control Valve BYPASS SHUT-OUT VALVE The bypass shut-out valve is provided in the rear of 4-spool and 5-spool section circuits. The bypass shut-out valve blocks the neutral circuit (return circuit to hydraulic oil tank) in 4-spool and 5-spool sections so that pressure oils in pumps 1 and 2 are combined. Therefore, amount of oil which flows to the cylinder increases and speed of the cylinder increases. NOTE: The bypass shut-out valve in 5-spool sec- tion is not used for the machine control. Operation 1.
When the attachment is operated on the machine equipped with the attachment (optional), pilot pressure from the pilot valve (optional) shifts the bypass shut-out valve in 4-spool section. 2. Therefore, as the neutral circuit in 4-spool section is blocked, pressure oil from pump 1 flows to the 5-spool section, is combined with pressure oil from pump 2 so that combined pressure oil is supplied to the auxiliary spool. 3. Consequently, speed of the attachment (optional) increases. From Pump 1 Attachment Pilot Pressure (Optional) T450-03-03-050 To Hydraulic Oil Tank NOTE: The illustration shows the bypass shut-out valve in 4-spool section. T3-3-40