LINK 8F4100 - Caterpillar

Illustration 1 g02596857
Quick Coupler Valve (1) Pressure reducing valve (2) Solenoid valve (3) Pressure reducing valveThe quick coupler valve is located on the inside of the right frame plate. The quick coupler valve reduces oil pressure from the main control valve and directs the flow of oil to a cylinder that is mounted on the quick coupler. To unlock a worktool, solenoid valve (2) is energized and oil is directed to the head end of the quick coupler cylinder. To lock a worktool, solenoid valve (2) is de-energized and oil is directed to the rod end of the cylinder.Pilot operated check valve (6) ensures that a worktool cannot become inadvertently unlocked.
Illustration 2 g02597137
Schematic of Quick Coupler Valve Group (A) Lock (B) Unlock (1) Pressure reducing valve (2) Solenoid valve (3) Pressure reducing valve (4) Implement pump (5) Quick coupler cylinder (6) Pilot operated check valve (7) Makeup valveQuick Coupler (Lock)
To lock a worktool, the operator lines up the worktool and increases the implement pump supply pressure. The operator then uses the monitor to send a request to the soft switch panel in order to lock the quick coupler. The soft switch panel de-energizes solenoid valve (2). Oil flow is directed from the implement pump (4) through pressure reducing valve (1) and pilot operated check valve (6). Oil then goes to the rod end of coupler cylinder (5) .Quick Coupler (Unlock)
To unlock the quick coupler, the operator uses the monitor to send a request to the soft switch panel. The soft switch panel then energizes solenoid valve (2), which directs the oil flow to the head end of quick coupler cylinder (1). Some of the oil is used to unseat pilot operated check valve (6). This allows the oil from the rod end to return to the tank.