OIL PRESSURE FEEDER OF WORK MACHINE CYLINDER

Title:

OIL PRESSURE FEEDER OF WORK MACHINE CYLINDER

Document Type and Number:

WIPO Patent Application WO/1990/002267

Kind Code:

A1

Abstract:

This invention relates to an oil pressure feeder which can prevent the abrupt fall of a work machine at the time of breakage of a piping arrangement for supplying a pressurized oil to a work machine cylinder and which can make the lowering speeds of a plurality of work machine cylinders equal. The oil pressure feeder includes a lock valve (B) consisting of a check valve (77), a poppet valve (78) and a pilot valve (79) that are disposed inside a valve housing (70) fixed to a cylinder tube (6), and an operation valve (C) for supplying selectively the pressurized oil to each pressure chamber (9a, 9b) for lifting and lowering the work machine cylinder (A) through each of two pressure oil feed piping arrangements (a, b). One (a) of these piping arrangements communicates with the pressure chamber (9a) for lifting through the check valve (77) and a first main port (75) communicating with this pressure chamber (9a) communicates with a tank port (74) through the poppet (32') of the poppet valve (78) whose opening/closing is controlled by the pilot valve (79).

Inventors:

KARAKAMA TADAO (JP)
ENDO HIROSHI (JP)
NUNOTANI SADAO (JP)
ISHIZAKI NAOKI (JP)

Application Number:

PCT/JP1989/000891

Publication Date:

March 08, 1990

Filing Date:

August 30, 1989

Export Citation:

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Assignee:

KOMATSU MFG CO LTD (JP)

International Classes:

E02F9/22; F15B13/01; F15B20/00; F16L55/10; (IPC1-7): F15B11/04; F15B11/16; F15B20/00

Foreign References:

JPS55149402A	1980-11-20
JPS52142169A	1977-11-26
JPH05433972A

Other References: