Power plants – Pressure fluid source and motor – Motor driven by motive fluid of system drives pump...
Reexamination Certificate
2001-05-09
2002-08-27
Ryznic, John E. (Department: 3745)
Power plants
Pressure fluid source and motor
Motor driven by motive fluid of system drives pump...
C060S494000
Reexamination Certificate
active
06438951
ABSTRACT:
STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT
Not applicable
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a hydraulic regeneration circuit using a rotary flow divider.
2. Background Information
Hydraulic systems are popular in applications involving hazardous, dirty, and nasty environments, such as coal mines, quarries, food processing plants, and construction sites. Much effort has been expended in trying to increase the efficiency and performance ranges of hydraulic drives.
Open loop hydraulic circuits are very common in industrial applications as they are often less expensive than circuits known, in the trade, as closed loop systems which comprise a fixed or variable displacement pump supplied with fluid by means of a charge pump.
Regeneration circuits are common to the trade on industrial equipment such as hydraulic presses. Some regeneration circuits using rotary dividers are in the public domain for industrial equipment such as hydraulic presses. A publication illustrating gerotor rotary flow dividers in regeneration circuits is the American Society of Agricultural Engineers Paper No. 911596 “Gerotor Rotary Flow Divider” by George Morgan, P.E., Sales Manager, White Hydraulics, Inc. presented at the 1991 International Winter Meeting sponsored by the American Society of Agricultural Engineers at the Hyatt Regency Chicago, Chicago, Ill., December, 1991 which is hereby incorporated by reference. The American Society of Agricultural Engineers is located at 2950 Niles Road, St. Joseph, Mich., 49085-9659, USA, Ph. (616) 429-0300, Fax: (616) 429-3852.
Hydra-Pneu Consulting, Inc., 726 Outer Gray Drive, Newburgh, Ind. 47630-1517, Ph. (812) 853-3234, conducted a course in “Advanced Fluid Power” in 1991, where the instructor, Bud Trinkel, discussed the use of a rotary flow divider in an open loop press circuit. One of his previous students had developed it, and brought it to his class. Applicant then introduced it to his employer at the time, White Hydraulics, Hopkinsville, Ky. The engineers doubted it would work. It did.
The state of the art uses flow dividers in regeneration circuits for open loop, fixed displacement circuits, where the flow divider is in constant operation. This contributes to system wear and noise.
As will be seen from the subsequent description, the preferred embodiments of the present invention broadens the performance range of an open loop hydraulic drive and overcomes exisitng limitations of open loop hydraulic drives.
SUMMARY OF THE INVENTION
The present invention is an improvement to an open loop hydraulic drive which broadens the performance range of said hydraulic drive with a given prime mover, hydraulic pump, and hydraulic drive combination. Said improvement comprises a rotary flow divider in conjunction with a valve means to isolate said flow divider from the open loop hydraulic drive. In the preferred embodiment of the present invention, a three way, two position, solenoid operated, spring return valve receives exhaust hydraulic flow from at least one hydraulic actuator such as, but not restricted to, a motor, a cylinder, or a rotary actuator. In normal, or low speed operation, the rotary flow divider is isolated from the hydraulic pump. For a high speed, or regeneration, cycle, the solenoid valve is actuated, and the exhaust hydraulic flow from the at least one hydraulic actuator outlet is diverted to a rotary flow divider. In the preferred embodiment of the present invention, for a 10 gallon per minute displacement pump in an open hydraulic drive, it would be a two section White ROLLERSTATOR (Reg. U.S. Trademark) gerotor flow divider. Fluid flow from a first section of the rotary flow divider sections is returned to a reservoir, while the fluid flow from a second section of the rotary flow divider is combined with fluid flow from the pump into the at least one hydraulic actuator. The effect of this arrangement is, for a rotary flow divider with sections of equal fluid displacement per revolution, that the fluid flow into the at least one hydrualic actuator becomes approximately double the output fluid flow of the hydraulic pump.
REFERENCES:
patent: 3962954 (1976-06-01), Jacob et al.
patent: 4102425 (1978-07-01), Marsden et al.
patent: 4295539 (1981-10-01), Beck et al.
patent: 4768340 (1988-09-01), Hamilton
patent: 5293745 (1994-03-01), Roche
patent: 5319932 (1994-06-01), Roche
patent: 6145287 (2000-11-01), Rosskopf
patent: 6279317 (2001-08-01), Morgan
patent: 6349543 (2002-02-01), Lisniansky
ASAE Paper #911596 “Gerotor Flow Divider” By Applicant (Figs. 15 & 16 Most Relevant).
“Fluid Power Circuit Explained” Cover Page Plus Pages FDI, FD2, & FD19-25. (Copied with Author's Permission).
Camoriano Theresa F.
Manley P.E. Mark A.
Price Gary K.
Ryznic John E.
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