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This is a record of a document published elsewhere, first published by the United States Patent and Trademark Office, as US-6050090-A, on 18 April 2000. OpenTechnical did not first disclose it. The identifier, hashes and timestamps below record what this library served and when, not when the material became public. View the original.

OT-2026-000003156

Control apparatus for hydraulic excavator

Published
Permanent URL
Classification
Industrial Motion & Power Transmission › Fluid Power
Assignee
KOBE STEEL LTD
Original source
US-6050090-A, the United States Patent and Trademark Office, 18 April 2000
Document SHA-256
395efcd29addd407c21267f81aefee7a2d3aa43d2373e75bb80d27de4801b1c5

Pressure sensors sense a pilot pressure Pa corresponding to the amount of boom raising operation of a boom operation lever and a pilot pressure Pb corresponding to the amount of arm pulling operation of an arm operation lever. When the condition of Pa>Pb is met during the horizontal pulling operation, the rate of supply of the working fluid to an arm actuating cylinder is reduced to a rate corresponding to the amount of operation of the operation lever. Conversely, when the condition Pa<Pb is met, the rate of supply of the working fluid to the boom actuating cylinder 5 is reduced to a rate corresponding to the amount of operation of the operating lever. Horizontal pulling operation for levelling the ground can be conducted without requiring high level of skill. The horizontal pulling work can be done easily and smoothly, while preventing the bucket from cutting into the ground and from floating above the ground.

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Abstract

Pressure sensors sense a pilot pressure Pa corresponding to the amount of boom raising operation of a boom operation lever and a pilot pressure Pb corresponding to the amount of arm pulling operation of an arm operation lever. When the condition of Pa>Pb is met during the horizontal pulling operation, the rate of supply of the working fluid to an arm actuating cylinder is reduced to a rate corresponding to the amount of operation of the operation lever. Conversely, when the condition Pa<Pb is met, the rate of supply of the working fluid to the boom actuating cylinder 5 is reduced to a rate corresponding to the amount of operation of the operating lever. Horizontal pulling operation for levelling the ground can be conducted without requiring high level of skill. The horizontal pulling work can be done easily and smoothly, while preventing the bucket from cutting into the ground and from floating above the ground.

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Publication information

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Citation

OpenTechnical Publication OT-2026-000003156, “Control apparatus for hydraulic excavator,” published September 15, 2026 at 19:40:24 UTC, https://opentechnical.org/p/OT-2026-000003156.

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This record reproduces a document published elsewhere and is provided for reference and study. Rights in the original remain with its owner. See the publication policy.