MULTISTEP TELESCOPIC-ARM FOR HYDRAULIC SHOVEL

PURPOSE:To prevent the bending loss of a telescopic shell from being generated by setting limit switches for detecting an arm extending position and bucket grounding on the external shell, and by causing the retaining force of an arm cylinder to be temporarily weakened when both the limit switches a...

Full description

Saved in:
Bibliographic Details
Main Authors TAKAMI MAKOTO, TERASAWA NOBORU
Format Patent
LanguageEnglish
Published 27.02.1992
Subjects
DREDGING
FIXED CONSTRUCTIONS
FOUNDATIONS
HYDRAULIC ENGINEERING
SOIL SHIFTING
Online AccessGet full text

Cover

More Information
Summary:PURPOSE:To prevent the bending loss of a telescopic shell from being generated by setting limit switches for detecting an arm extending position and bucket grounding on the external shell, and by causing the retaining force of an arm cylinder to be temporarily weakened when both the limit switches are worked. CONSTITUTION:The external shell 3a of a telescopic arm is provided with an arm-telescopic ascending or descending cylinder 6, and limit switches 9, 10 for detecting the extending position of an intermediate pipe 3b and the grounding of a bucket 5 fitted at the tip of an internal pipe 3c. After that, when the limit switches 9, 10 are closed, then a relay is operated, and the relief valve of the working circuit of an arm cylinder 4 is opened, and the retaining pressure is temporarily reduced. As a result, the bending loss of the telescopic arm 1 can be prevented from being generated.
Bibliography:Application Number: JP19900172590