The shovel crane is a machine configuration used to lift certain objects off the ground. Refer to Operation and Maintenance Manual, "Shovel Crane Operation" for additional information regarding the shovel crane mode.
Note: Set the machine to slow travel speed (Turtle) mode to maintain safety while traveling with a lifted object.
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| Illustration 1 | g03344613 |
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Component overview (10) Bucket lock solenoid (14) Left Joystick (15) Main control valve (17) Boom lowering control valve (BLCV) (24) Stick lowering control valve (SLCV) (29) Hook (41) Boom position sensor (42) Stick position sensor | |
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| Illustration 2 | g03344611 |
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Boom and stick position sensors (41) Boom position sensor (42) Stick position sensor | |
Boom position sensor (41) and stick position sensor (42) determines the angle and location of the implements. This information is used to make sure that the load being lifted will not be positioned outside the safe operating range of the crane.
Boom pressure sensor (18), boom angle sensor (41), and stick angle sensor (42) are used to help calculate the weight of the lifted load.
The following is an example of using the shovel crane with a BOOM UP and BUCKET OPEN operation.
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| Illustration 3 | g03344497 |
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Shovel crane schematic- BOOM UP and BUCKET OUT operations (1) Pilot pump (2) Drive pump (3) Hydraulic tank (4) Pilot oil filter (5) Pilot manifold (6) Line (Pilot) (7) Pilot oil distribution block (8) Pilot control valve (9) Line (Pilot) (10) Bucket lock solenoid (11) Bucket rod pressure switch (12) Line (Pilot) (13) Line (Pilot) (14) Pilot control valve (15) Main control valve (16) Drift reduction valve (17) Boom lowering control valve (BLCV) (18) Boom head pressure sensor (19) Boom cylinder (20) Boom control valve (21) Bucket cylinder (22) Bucket control valve (23) Stick cylinder (24) Stick lowering control valve (SLCV) (25) Parallel feeder passage (26) Line (Pilot) | |
Boom lowering control valve (17) prevents a sudden drop of the boom if a boom line fails. The boom lowering control valve also enables the technician to lower the boom manually. For additional information on the boom lowering control valve, refer to Systems Operation, "Boom Lowering Control Valve"
Pilot oil delivery from pilot pump (1) flows into pilot oil filter (4). The oil then flows into pilot manifold (5). Pilot oil flows from the pilot manifold through pilot line (6) and into pilot oil distribution block (7). The oil in pilot oil distribution block (7) flows through line (9) and to pilot control valve (14).
When pilot control valve (14) is moved into the BOOM UP position, pilot oil is directed into the BOOM UP pilot oil circuit. Oil flows from pilot control valve (14) to line (13) and shifts boom control valve (20) upwards. This action allows the oil from drive pump (2) to enter boom cylinder (19).
When left joystick (14) is moved to the Bucket OPEN position, pilot oil flows from pilot control valve (14) and through line (12). The pilot oil then flows into bucket lock solenoid (10). The bucket lock solenoid is turned off due to the machine being set to crane mode. This action does not allow pilot oil to reach bucket control valve (22). Bucket lock solenoid (10) prevents a BUCKET OPEN condition while the shovel crane is in operation. This action prevents an accidental interference with the lifting wire and the bucket, which can cause the wire or hook (29) to break.
Drive pump (2) provides hydraulic oil to the implements. Hydraulic oil from drive pump (2) flows into main control valve (15). The oil flows through parallel feeder passage (25) and through boom control valve (20). Then the oil flows into drift reduction valve (16) , into boom lowering control valve (17), and into boom cylinder (19).
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| Illustration 4 | g03344936 |
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Bucket lock solenoid (A1) Port (to bucket control valve) (P1) Port (from pilot control valve) (T1) Port (to hydraulic tank) (1) Bucket lock solenoid | |
Bucket lock solenoid (1) is energized when the machine is not in shovel crane mode. This action allows the pilot oil from the pilot control valve to shift the bucket control valve to perform a BUCKET OPEN operation. When bucket lock solenoid (1) is de-energized, pilot oil is not allowed to flow to the bucket control valve. The bucket control valve will not shift, which prevents the bucket from opening.
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| Illustration 5 | g03344498 |
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(17) Boom lowering control valve (BLCV)
(19) Boom cylinder (20) Boom control valve (27) Port (from control valve) (28) Port (to head end of boom cylinder) (29) Valve (30) Relief valve (31) Piston (32) Spool (33) Spring (34) Spring (35) Passage (36) Passage | |
The boom lowering control valve is located on the head end of the boom cylinder.
The boom lowering control valve has two functions:
- The boom lowering control valve prevents the boom from falling if a hydraulic supply line fails or if a supply tube to a boom cylinder fails.
- The boom lowering control valve allows the operator to lower the boom manually when the engine is shut down.
Reference: For information on lowering the boom manually, see Operation and Maintenance Manual, "Equipment Lowering with Engine Stopped".
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| Illustration 6 | g03344499 |
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Boom Lowering Control Valve - Boom Raise (14) Joystick (17) Boom lowering control valve (BLCV) (19) Boom cylinder (20) Boom control valve (27) Port (from control valve) (28) Port (to head end of boom cylinder) (29) Valve (30) Relief valve (31) Piston (32) Spool (33) Spring (34) Spring (36) Passage | |
When joystick (14) is moved to the BOOM RAISE position, hydraulic pump oil flows from boom control valve (20) to port (27) of boom lowering control valve (17). The oil pressure unseats valve (29) and flows into two paths. The first path is through port (28) and into the head end of boom cylinder (19). The second path is through passage (36) and into the spring side of valve (29).
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| Illustration 7 | g03344500 |
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Boom Lowering Control Valve - Boom Lower (14) Joystick (17) Boom lowering control valve (BLCV) (19) Boom cylinder (20) Boom control valve (27) Port (from control valve) (28) Port (to head end of boom cylinder) (29) Valve (30) Relief valve (31) Piston (32) Spool (33) Spring (34) Spring (36) Passage (37) Port (drain) (38) Port (pilot) (39) Lip | |
When joystick (14) is moved into the BOOM LOWER position, pilot oil flows into port (38). The pilot oil shifts piston (31) down and causes spool (32) to shift downwards. Oil on the spring (34) side of valve (29) drains through passage (36) and flows through port (37) to the hydraulic tank.
Oil pressure from the head end of boom cylinder (19) will create enough pressure on lip (39) to push valve (29) down. This action allows the oil to flow out of port (27) and into the boom control valve (20).
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| Illustration 8 | g03344502 |
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Boom Lowering Control Valve - Boom Hold (14) Joystick (17) Boom lowering control valve (BLCV) (19) Boom cylinder (20) Boom control valve (27) Port (from control valve) (28) Port (to head end of boom cylinder) (29) Valve (30) Relief valve (31) Piston (32) Spool (33) Spring (34) Spring (36) Passage (37) Port (drain) (38) Port (pilot) | |
When the joystick (14) is moved to the NEUTRAL position, the boom drift reduction valve moves into the HOLD position.
Spring (34) moves valve (29) up. This action prevents oil from leaking between port (28) and port (27).
Relief Operation of the Cylinder Head End
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| Illustration 9 | g03344511 |
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Boom Lowering Control Valve - Relief (14) Joystick (17) Boom lowering control valve (BLCV) (19) Boom cylinder (20) Boom control valve (27) Port (from control valve) (28) Port (to head end of boom cylinder) (29) Valve (30) Relief valve (31) Piston (32) Spool (33) Spring (34) Spring (36) Passage (39) Chamber (return oil) (40) Chamber (boom head end oil) | |
When the boom is pushed downward by an outside force, the oil pressure in port (26) increases. The oil pressure is sensed at relief valve (30). When oil pressure overcomes the relief valve setting, the relief valve allows oil to fill chamber (39). The oil pressure in chamber (39) moves spool (32) downward. The oil in chamber (39) flows through spool (32) to the hydraulic tank. The shifting of spool (32) allows the oil in passage (36) to drain into the hydraulic tank. This action lowers the hydraulic oil pressure until the hydraulic oil pressure is lower than the relief valve setting.
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| Illustration 10 | g03344512 |
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(24) Stick lowering control valve (SLCV)
(23) Stick cylinder (43) Stick control valve (54) Port (from control valve) (53) Port (to rod end of Stick cylinder) (52) Valve (47) Relief valve (45) Piston (46) Spool (49) Spring (51) Spring (55) Passage (50) Passage | |
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| Illustration 11 | g03344513 |
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Stick lowering control valve - Stick Out (8) Joystick (24) Stick lowering control valve (SLCV) (23) Stick cylinder (43) Stick control valve (44) Port (pilot) (45) Piston (46) Spool (47) Relief valve (48) Port (drain) (49) Spring (50) Passage (51) Spring (52) Valve (53) Port (to head end of stick cylinder) (54) Port (from control valve) | |
When joystick (8) is moved to the STICK OUT position, hydraulic pump oil flows from stick control valve (43) to port (54) of stick lowering control valve (24). The oil pressure unseats valve (52) and flows into two paths. The first path is through port (53) and into the head end of stick cylinder (23). The second path is through passage (50) and into the spring side of valve (52).
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| Illustration 12 | g03344514 |
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Stick lowering control valve - Stick In (8) Joystick (24) Stick lowering control valve (SLCV) (23) Stick cylinder (43) Stick control valve (44) Port (pilot) (45) Piston (46) Spool (47) Relief valve (48) Port (drain) (49) Spring (50) Passage (51) Spring (52) Valve (53) Port (to head end of stick cylinder) (54) Port (from control valve) | |
When joystick (8) is moved into the STICK IN position, pilot oil flows into port (44). The pilot oil shifts piston (45) down and causes spool (46) to shift downwards. Oil on the spring (51) side of valve (52) drains through passage (50) and flows through port (48) to the hydraulic tank.
Oil pressure from the head end of stick cylinder (23) will create enough pressure on lip (56) to push valve (52) down. This action allows the oil to flow out of port (54) and into the stick control valve (43).
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| Illustration 13 | g03344515 |
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Stick lowering control valve - Stick Hold (8) Joystick (24) Stick lowering control valve (SLCV) (23) Stick cylinder (43) Stick control valve (44) Port (pilot) (45) Piston (46) Spool (47) Relief valve (48) Port (drain) (49) Spring (50) Passage (51) Spring (52) Valve (53) Port (to head end of stick cylinder) (54) Port (from control valve) | |
When the joystick (8) is moved to the NEUTRAL position, the stick drift reduction valve (24) moves into the HOLD position.
Spring (51) shifts valve (52) up. This action prevents oil from leaking between port (54) and port (53).
Relief Operation of the Cylinder Head End
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| Illustration 14 | g03344517 |
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Stick lowering control valve - Relief (8) Joystick (24) Stick lowering control valve (SLCV) (23) Stick cylinder (43) Stick control valve (44) Port (pilot) (45) Piston (46) Spool (47) Relief valve (48) Port (drain) (49) Spring (50) Passage (51) Spring (52) Valve (53) Port (to head end of stick cylinder) (54) Port (from control valve) (55) Chamber (56) Chamber | |
When the stick is pushed downward by an outside force, the oil pressure in port (53) increases. The oil pressure is sensed at relief valve (47). When oil pressure overcomes the relief valve setting, the relief valve allows oil to fill chamber (56). The oil pressure in chamber (56) moves spool (46) downward. Oil then flows through spool (46). The shifting of spool (46) allows the oil in passage (50) to drain into the hydraulic tank. This action lowers the hydraulic oil pressure until the hydraulic oil pressure is lower than the relief valve setting.