BRACKET AS 2020212 - Caterpillar

Main Control Valve Cross Section
(1) Supply port. (13) Spool (not used). (14) Supply passage. (15) Tank passage. (16) Load check valve. (17) Passage. (18) Passage. (19) Housing. (20) Tilt circuit spool. (21) Springs. (22) Springs. (23) Housing. (24) Tilt cylinder head end port. (25) Tilt cylinder rod end port. (26) Passage. (27) Lift circuit spool.Since the control valve functions the same for bucket DUMP as for bucket TILT BACK, RAISE and LOWER, only the bucket DUMP operation will be explained.The control valve contains two functioning spools (20) and (27). These spools are pilot operated to control the bucket tilt and lift operations. The third spool (13) is not used in the control valve on this machine.With the engine running, oil flows from the pumps into the control valve at port (1). The oil from the two pumps combines in port (1).The combined pump oil in passage (14) flows to spool (20). When the control levers for lift and tilt are in the HOLD positions, this combined oil flows around spool (20) and through passage (26). Then the oil flows around spool (27) and out passage (15) back to the hydraulic tank.
Main Control Valve Group
(1) Supply port. (4) TILT BACK pilot port. (5) Tilt cylinder head port. (6) Manifold. (7) Tilt cylinder rod port. (8) RAISE pilot port. (9) DUMP pilot port. (10) LOWER pilot port. (11) Lift cylinder head port. (12) Lift cylinder rod port.When the operator places the control lever in the DUMP position pilot oil flows into housing (23). The pilot oil acts against spool (20), overcomes the force of spring (22) located in housing (19) and causes the spool to move to the left.When spool (20) moves left it blocks the flow of pump supply oil through passage (14) to return passage (15). At the same time it blocks oil flow through load check valve (16) to passage (17) and passage (24) to the head end of the tilt cylinder.Supply oil does force load check valve (16) to open and allow oil to flow through passage (18) past spool (20) and into port (25). The oil flows through port (25) and out port (7).Oil flows from port (7) in the control valve body to the rod end of the tilt cylinder. This oil then flows into the rod end of the tilt cylinder. The tilt cylinder rod retracts and causes the bucket to dump.Return oil from the head end of the tilt cylinder flows through port (5) into port (24). Because spool (20) is positioned to the left, the return oil flows through port (24), past spool (20) and out passage (15) back to the hydraulic tank.Kickout Systems
Lift Kickout
Lift Kickout Components
(1) Magnet. (2) Lift arm. (3) Control switch. (4) Magnet holder.The lift kickout is electromagnetic system. When it is activated, it causes the lift control lever to move from the detent on the RAISE position to the HOLD position, prior to the lift arms reaching the top of their travel.Holder (4) is attached to lift