Fluid handling – Systems – With selective motion for plural valve actuator
Patent
1991-10-17
1993-05-11
Michalsky, Gerald A.
Fluid handling
Systems
With selective motion for plural valve actuator
91513, 91522, 1375961, F15B 1306
Patent
active
052092631
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a pilot valve assembly including a manual control lever which is swayed in operation back/forth and rightward/leftward so as to select a desired one of oil passages formed in the assembly, through which one a pressure oil is supplied to a desired one of actuators used in a hydraulic circuit.
DESCRIPTION OF THE PRIOR ART
Hitherto, it is known that, for example as shown in FIG. 6, in a conventional pilot valve assembly of this kind: each of four spool valves 4 is slidably mounted in a main valve body 1 of the assembly so as to permit and prevent communication of pressure oil from a pressure-oil port 2 to an outlet port 3 through an oil passage 4a formed in each of the spool valves 4; each of four guide sleeves 5 is mounted in the main valve body 1 so as to be coaxially arranged with each of the spool valves 4; each of four spring retainers 6 is movably mounted in the main valve body 1 so as to be disposed under each of the guide sleeves 5; each of four main compression springs 7 is so disposed under each of the spring retainers 6 as to axially urge the same 6 upward so that each of the spring retainers 6 is brought into a close contact with each of the guide sleeves 5, whereby each of four pistons 8 is urged upward under the influence of a resilient force exerted by each of the main compression springs 7, each of the pistons 8 being slidably mounted in each of the guide sleeves 5; each of four auxiliary compression springs 9 resiliently keeps each of the spool valves 4 in its shut-off position; a plate member 10 is fixedly mounted on an upper portion of the main valve body 1 so that the guide sleeves 5 are fixed to the main valve body 1, the plate member 10 being provided with a through-hole 11 through which a threaded base portion 12a of a universal joint member 12 is threadably connected with a threaded hole of the upper portion of the main valve body 1; and a swingable upper portion 12b of the universal joint member 12 is fixedly connected with a lower end of a threaded portion 13 of a manual control lever 15, which threaded portion 13 is threadably connected with a threaded hole of a disc member 14 so that the disc member 14 is coaxially arranged with the threaded portion 13 of the manual control lever 15. In operation of the conventional pilot valve assembly having the above construction, when an operator or user sways the manual control lever 15 of the assembly back/forth and rightward/leftward as required, the disc member 14 is also swayed so as to press a desired one of the pistons 8 downward, whereby a corresponding one of the spool valves 4 is displaced into its communication position in which the spool valve 4 permits the pressure oil (which is confined in the pressure-oil port 2) to be delivered to an outlet port 3 of the pilot valve assembly.
In general, the pilot valve assembly is used in a hydraulic circuit of a working vehicle such as power shovels and like construction machines provided with hydraulic actuators so as to control the actuators in operation. More particularly, in the hydraulic circuit: the pilot valve assembly has its pair of the outlet ports 3 connected with a pair of pilot-pressure chambers of a pilot-operated directional control valve; and, when the manual control lever 15 is swayed by the operator, the pressure oil is delivered to a desired one of the pilot-pressure chambers of the directional control valve to operate the same. As described above, in the conventional pilot valve assembly provided with the manual control lever 15, the operator selects a desired one of the pistons 8 by swaying the control lever 15 as required, so that a desired one of the outlet ports 3 of the pilot valve assembly (to which one the pressure oil should be delivered) is selected. In operation, for example, when the control lever 15 is swayed forward by the operator, the pressure oil is delivered from the pressure-oil port 2 to a corresponding one of the outlet ports 3. On the other hand, when the control lever 15 is swayed backward, th
REFERENCES:
patent: 3646959 (1972-03-01), Connett et al.
patent: 3927603 (1975-12-01), Bernhoft
patent: 4184512 (1980-01-01), Pignolet
Kabushiki Kaisha Komatsu Seisakusho
Michalsky Gerald A.
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