FORKLIFT HYDRAULIC CONTROL APPARATUS

• Main Authors: MATSUO TSUTOMU, UEDA SUKENORI, INOUE HIROSHI, ISHIKAWA HIROHIKO
• Format: Patent
• Language: English
• Published: 19.08.2013
• Subjects: HAULING; HOISTING; HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDEDFOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCEDIRECTLY TO THE SURFACE OF A LOAD; LIFTING; PERFORMING OPERATIONS; TRANSPORTING

PROBLEM TO BE SOLVED: To move a plurality of objects properly when the plurality of objects are moved simultaneously.SOLUTION: A regeneration lowering proportional valve 33 is arranged on an oil passage K2 for circulating hydraulic oil discharged from a lift cylinder 14 to a hydraulic pump motor 30. A simultaneous-operation lowering proportional valve 34 is arranged on an oil passage K3 for circulating the hydraulic oil discharged from the lift cylinder 14 to a drain side (oil tank T side). When a fork is lowered by independent operation, a control section S controls a flow rate circulated in the regeneration lowering proportional valve 33 so as to circulate the hydraulic oil at a flow rate corresponding to a manipulated variable of a lift lever 22. On the other hand, when simultaneous operation is entered, which is obtained by adding forward tilting or backward tilting operation of a mast to the lowering operation of the fork as the independent operation, the control section S controls the flow rate circulated in the regeneration lowering proportional valve 33 and the flow rate circulated in the simultaneous-operation lowering proportional valve 34 so as to circulate hydraulic oil at a flow rate corresponding to a manipulated variable of the lift lever 22.