The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 10, 1985
Filed:
Jan. 18, 1984
Rudolf Brunner, Baldham, DE;
Abstract
The invention relates to a hydraulic control valve comprising a housing w a housing bore (2) formed therein, a control piston (3) being guided in said housing bore for sliding displacement between a neutral position (n) for zero-pressure through-flow and at least one control position (I, II), and further comprising a pressure inlet (6) opening in said housing bore (2), a through-passage (8) in said control piston (3), and a discharge outlet (7) communicating with said pressure inlet via said through-passage in the zero-pressure through-flow position. In a control valve of this type, particularly if employed in a high pressure hydraulic system, displacement of the control piston from a control position to the neutral position is hampered by unsatisfactory pressure compensation. In accordance with the invention, this undesirable effect is avoided by forming substantialy diametrally opposite said discharge outlet (7) a relief area (9, 9', 16, 17, 18, F26) compensating at least the effective area of said discharge outlet and being of substantially the same size as the discharge outlet and subjected to the same pressure as the latter. For ensuring effortless displacement of the control piston of an upstream control valve from its neutral position in a battery-type arrangement of a plurality of control valves even if a downstream control valve is in its control position, there is further provided an area (33) compensating the effective area of the relief area (9, 9', 16, 17, 18, F26) said compensating area communicating with return pressure at least in the neutral position (N).