Title:
CRANE
Document Type and Number:
Japanese Patent JP2017202909
Kind Code:
A
Abstract:
PROBLEM TO BE SOLVED: To provide a crane which can adjust a pressure of working fluid by manual operation even if proportional pressure reduction valves are failed, and can consequently move actuators at a proper speed.SOLUTION: In a crane 1 constituting a hydraulic system H including actuators 25, 35 and 45, direction changeover valves 20, 30 and 40 for switching flow directions of working fluid for moving the actuators 25, 35 and 45, and proportional pressure reduction valves 26, 36 and 46 for freely adjusting a pressure of the working fluid for moving the direction changeover valves 20, 30 and 40, oil passages 51, 52 for guiding the working fluid are provided at one or plurality of the proportional pressure reduction valves 26, 36 and 46, emergency proportional pressure reduction valves 50 which can be adjusted in openings by manual operation are arranged in the oil passages 51, 52, and the emergency proportional pressure reduction valves 50 are controlled so as to maintain fully-opened states at normal time, and function as manual operation tools for adjusting the pressure of the working fluid without being controlled at an emergency.SELECTED DRAWING: Figure 4
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Inventors:
KAWABUCHI NAOTO
MASUDA HISATAKA
YOSHIDA HISAFUMI
MASUDA HISATAKA
YOSHIDA HISAFUMI
Application Number:
JP2016095684A
Publication Date:
November 16, 2017
Filing Date:
May 11, 2016
Export Citation:
Assignee:
TADANO LTD
International Classes:
B66C13/20; B66C23/693; B66C23/82; B66C23/86; F15B11/08; F15B20/00
Attorney, Agent or Firm:
Yanouchi Foreign Patent Office