| 摘要 |
A valve block for hydraulic excavators having at least two sets of valves which are each coupled to their pump. The valves are of the type which, in the unactuated state, allows the passage of pressure medium. The hydraulic devices for executing working movements of the excavator are each coupled to their valve in each set. The valves in the one set are coupled in series, counted from the pump in the sequence the valve which is coupled to the hydraulic device for the first working movement of the excavator, the valve which is coupled to the hydraulic device for the second working movement of the excavator, and the valve which is coupled to the hydraulic device for the third working movement of the excavator. The valves in the second set are similarly coupled in series counted from the pump in the sequence the valve which is coupled to the hydraulic device for the third working movement of the excavator, the valve which is coupled to the hydraulic device for the second working movement of the excavator and the valve which is coupled to the hydraulic device for the first working movement of the excavator. In the case when the excavator has caterpillar tracks driven by means of hydraulic motors, one valve for each of the hydraulic motors may be coupled before, after or in parallel with each series of valves to the hydraulic devices for executing the working movements of the excavator.
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