Hydraulic actuator 202 (e.g. for aircraft landing gear) having an extension chamber 206 and a retraction chamber 208, and a bypass line 222 connecting and short circuiting the two chambers, the bypass line having flow restrictor 224 and a bypass valve 226 (e.g. in series). The valve has two valve actuating mechanisms of dissimilar and different types, one may be manually operated, the other may be a shape-changing material (e.g. phase change material, shape-memory material) which opens the valve when the temperature decreases below threshold (fig 6b). Flow restrictor may have 4 to 14 mm2 cross-sectional area. A valve status sensor may sense valve position or hydraulic fluid parameter in the bypass line. The bypass line may be external to the hydraulic ram connecting to the hydraulic lines 216, 218, within the wall of the hydraulic ram housing, or within the moveable piston 204.


    Access

    Download


    Export, share and cite



    Title :

    Hydraulic actuator


    Contributors:
    SEAN KERR (author)

    Publication date :

    2025-06-18


    Type of media :

    Patent


    Type of material :

    Electronic Resource


    Language :

    English


    Classification :

    IPC:    F15B SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL , Druckmittelbetriebene Systeme allgemein / B64C AEROPLANES , Flugzeuge



    HYDRAULIC ACTUATOR

    MARGER THIBAUT / POULY FRANÇOIS / LABASCOULE JEAN-CHRISTOPHE | European Patent Office | 2019

    Free access

    HYDRAULIC ACTUATOR

    ITO KOJI | European Patent Office | 2016

    Free access

    Hydraulic actuator

    European Patent Office | 2024

    Free access

    HYDRAULIC ACTUATOR AND MULTI-CYLINDER HYDRAULIC ACTUATOR SYSTEM

    KRACKE JEREMY | European Patent Office | 2019

    Free access

    Hydraulic actuator

    SEAN KERR | European Patent Office | 2025

    Free access