Fluid handling – Systems – Supply and exhaust
Patent
1989-10-17
1991-08-20
Michalsky, Gerald A.
Fluid handling
Systems
Supply and exhaust
91454, 13759616, 137884, F15B 13043
Patent
active
050405659
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a control valve system for supplying a pressure oil to hydraulic equipment such as hydraulic cylinders, hydraulic motors and the like to control that hydraulic equipment in operation, and more particularly to a pilot operated control valve system for conducting directional controls of a plurality of valves of the system by means of pilot pressure oil.
DESCRIPTION OF THE PRIOR ART
Hitherto, it is known that, for example as shown in FIG. 1, in a control valve system of this kind that a pressure oil discharged from a hydraulic pump 1 is supplied to a first chamber 3.sub.1 and a second chamber 3.sub.2 of a hydraulic device 3 through a first meter-in valve 2.sub.1 and a second meter-in valve 2.sub.2, respectively, the meter-in valves 2.sub.1, 2.sub.2 being two-way valves. The pressure oil which entered the first chamber 3.sub.1 and the second chamber 3.sub.2 is discharged into a tank 5 through a first meter-out valve 4.sub.1 and a second meter-out valve 4.sub.2, respectively, the meter-out valves 4.sub.1, 4.sub.2 being two-way valves. In case that both of the first meter-in valve 2.sub.1 and the second meter-out valve 4.sub.2 are opened, the pressure oil is supplied to the first chamber 3.sub.1 of the hydraulic equipment 3, while the pressure oil having entered the second chamber 3.sub.2 of the equipment 3 is discharged from the second chamber 3.sub.2 of the equipment 3 into the tank 5. In case that both of the second meter-in valve 2.sub.2 and the first meter-out valve 4.sub.1 are opened, the pressure oil is supplied to the second chamber 3.sub.2 of the hydraulic equipment 3, while the pressure oil having entered the first chamber 3.sub.1 of the hydraulic equipment 3 is discharged therefrom into the tank 5.
In addition, a pilot operated control valve system is known, in which each of the valves described above is constructed of a pilot operated valve and further comprises a first and a second pilot valve, which first pilot valve conducts directional controls of the first meter-in valve 2.sub.1 and the second meter-out valve 4.sub.2, and which second pilot valve conducts directional controls of the second meter-out valve 2.sub.2 and the first meter-out valve 4.sub.1.
On the other hand, in a power shovel, there are employed at least six hydraulic devices comprising: a boom derricking cylinder, an arm hydraulic cylinder, a bucket hydraulic cylinder, a swing hydraulic motor, a left-hand traveling hydraulic motor and a right-hand traveling hydraulic motor, to which hydraulic equipment the pressure oil is supplied through four valves. As a result, the power shovel requires at least 24 valves and 12 pilot valves in operation.
In the conventional pilot operated control valve system described above, it is required for a valve housing 6 of the control valve system to have in the interior thereof four valves comprising the first meter-in valve 2.sub.1, the second meter-in valve 2.sub.2, the first meter-out valve 4.sub.1 and the second meter-out valve 4.sub.2 and to form therein two pump ports 7.sub.1, 7.sub.2, two tank ports 8.sub.1, 8.sub.2, and four additional ports 9.sub.1, 9.sub.2, 9.sub.3, 9.sub.4, the first and the second pilot valve, and pilot passages communicating with these pilot valves. Consequently, in case that the above pilot operated control valve system is employed in the power shovel, it is required for the valve housing 6 of the control valve system of the power shovel to have 24 valves, 12 pilot valves, a plurality of the pump port passages, a plurality of the tank port passages, a plurality of the additional port passages and the pilot passages, which cause the valve housing 6 to be a large sized one. In addition, in the valve housing 6 of the pilot operated control valve system, it is very cumbersome to form each of the above port passages.
SUMMARY OF THE INVENTION
In view of such circumstances described above, the present invention was made. Consequently, it is an object of the present invention to provide a small-sized pilot operated co
REFERENCES:
patent: 2984257 (1961-05-01), McCormick
patent: 3556144 (1971-01-01), Bickers et al.
patent: 4711267 (1987-12-01), Schwelm
Ishizaki Naoki
Karakama Tadao
Oda Yosuke
Kabushiki Kaisha Komatsu Seisakusho
Kananen Ronald P.
Michalsky Gerald A.
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