Lafayette 3608 Engine BCC4200 - Caterpillar

Illustration 1 g03887979
Side of swing motor
(1) Block
(2) Swing motor
(3) Anti-reaction valve
(4) Anti-reaction valve
(35) Fine swing solenoid valve
Illustration 2 g01761734
Fine swing solenoid valve
(1) Block
(8) Passage
(9) Passage
(10) Passage
(31) Passage
(35) Solenoid
(36) Fine swing valve
(37) Passage
(38) Passage
(39) Spool
(40) Spring
(41) Orifice
(42) Orifice
Illustration 3 g01816116
The fine swing control switch is located on the right side control panel.
The fine swing control is installed in order to ensure an exact movement of the swing with minimal shock load. This control is done by equalizing the oil pressure in passage (8) and (10).When fine swing solenoid (35) is de-energized, spool (39) is in the NEUTRAL position. Spool (39) is located in valve (36). The NEUTRAL position creates a closed connection between passages (37) and (38). In this position, the swing circuit operates in the normal manner.When the fine swing control switch is ON, solenoid (35) is energized. Spool (39) shifts downward against the force of spring (40). With the spool in this position, passage (8) is open to passage (10) through passages (37) and (38). Orifices (41) and (42) control the flow rate. Orifices (41) and (42) are located in block (1).Because the right and the left swing circuits are now connected to each other, some of the outlet oil is allowed to flow to the inlet side. The operation of the swing circuit is more precise with this connection.Note: When the fine swing control switch is ON, the swing brake is OFF.