RETAINER-SEAL 5Y1696 - Caterpillar

Illustration 1 g00497820
Schematic for quick-drop valve (A) Line to control valve (B) Quick-drop valve (C) Bulldozer lift cylinders (D) Line to rod ends of cylinders (E) Line to head ends of cylinders (F) Bypass valve (G) Bulldozer tilt cylinderA single quick-drop valve is installed at the center of the top of the radiator guard. The valve allows the bulldozer blade to drop quickly to the ground.When the operator lowers the blade quickly, the oil pressure in the head ends of the lift cylinders drops. The hydraulic circuit from the pump to the head ends of the lift cylinders can not supply sufficient oil flow in order to maintain the pressure. The valve diverts oil from the rod end of the lift cylinders to the head end of the lift cylinders.The quick-drop valve minimizes pause time. The valve permits full down pressure after the blade hits the ground.Bulldozer Control Lever in the RAISE Position
Illustration 2 g00497822
Quick-drop valve with the bulldozer control lever in the RAISE position (1) Cover (2) Passage to the head ends of the lift cylinders (3) Passage (4) Passage (5) Passage to the LOWER port of the control valve (6) Valve spool (7) Spring (8) Cover (9) Plunger (10) Orifice sleeve (11) Passage to RAISE port of the control valve (12) Passage to the rod ends of the lift cylinders (AA) High pressure oil from the implement hydraulic pump (LL) Tank oilWhen the bulldozer control lever is moved to RAISE position, pump oil enters the quick-drop valve at passage (11). The oil flow moves orifice sleeve (10) to the right. The oil flows past orifice sleeve (10) and out passage (12) to the rod ends of the bulldozer lift cylinders. Return oil from the head ends of the cylinders enters the valve at passage (2). The oil flows past spool (6) and out passage (5) to the control valve.Return oil pressure enters passage (4) in spool (6), which raises the pressure on the right end of plunger (9). However, the hydraulic circuit pressure exceeds the return oil pressure when the bulldozer control lever is in the RAISE position. The circuit pressure on the left end of plunger (9) keeps the plunger shifted to the right. Hydraulic circuit pressure also increases in passage (3) to the right end of spool (6). Spring (7) keeps spool (6) shifted to the right.Bulldozer Control Lever in the Slow LOWER Position
Illustration 3 g00497826
Quick-drop valve with the bulldozer control lever in the slow LOWER position (1) Cover (2) Passage to the head ends of the lift cylinders (3) Passage (4) Passage (5) Passage to the LOWER port of the control valve (6) Valve spool (7) Spring (8) Cover (9) Plunger (10) Orifice sleeve (11) Passage to RAISE port of the control valve (12) Passage to the rod ends of the lift cylinders (AA) High pressure oil from the implement hydraulic pump (BB) Return oil (CC) Return oil after the pressure reduction through the orificeThe bulldozer control lever is moved to the LOWER position below 75