| 摘要 |
A simplified bootstrap control valve (122) is provided wherein the control valve's load circuit is not interdicted in any way. The simplified bootstrap control valve includes a four-way control valve having input slots formed in an open-center manner, intermediate slots formed in an open-center manner, return slots formed in a closed-center manner, and a passage for picking off the pressure value present in the intermediate slots. The pressure value present in the intermediate slots is utilized for regulating pumping apparatus providing fluid to the simplified bootstrap control valve such that the pressure value present in the intermediate slots is substantially maintained at a preselected value. A simplified servo motor (704) - positive displacement pump assembly (700) of integrated construction is also provided. The simplified servo motor-positive displacement pump assembly (700) includes a common housing and a quill drive (710, 712).
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