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:
Oct. 09, 2001
Filed:
Oct. 08, 1999
Pil Gyou Kwag, Euiwang-si, KR;
Daewoo Heavy Industries Ltd., Incheon, KR;
Abstract
A bulk material pump device includes first and second hydraulic drive cylinders capable of causing alternate reciprocating movement of the corresponding pumping pistons to pump concrete contained in a hopper through a transportation conduit. The first drive cylinder has a cylinder housing whose bore is divided into a base chamber and a head chamber by a drive piston slidably received in the cylinder housing. The base chamber is in fluid communication with an oil pump while the head chamber is connected to the second drive cylinder. Under a loaded operation condition, a part of the pressurized oil in the base chamber is admitted into the head chamber via a head bypass line at the end of retracting movement of the drive piston and almost the same amount of the oil is returned back from the head chamber to the base chamber via a base bypass line at the end of extending movement thereof. Under an idle operation condition, the oil admitted into the head chamber is not returned back to the base chamber but, instead, will be drained to an oil tank by the action of a solenoid valve and a cartridge valve provided along a drain line.