Hydraulic mechanism

Claim 1

A FLUID ACTUATED LOAD CONTROLLING DEVICE COMPRISING, A LOAD SUPPORTING COLUMN HAVING AT LEAST TWO ELONGATED SLIDE BEARING PORTIONS OF DIFFERENT CROSS-SECTIONAL DIMENSION, AN OUTER ASSEMBLY FORMING AN ANNULAR FLUID CHAMBER ABOUT THE COLUMN, SAID OUTER ASSEMBLY INCLUDING A PAIR OF END SECTIONS OF DIFFERENT CROSS-SECTIONAL DIMENSIONS INTERCONNECTED BY AN INTERMEDIATE SECTION TO VARY THE CROSS-SECTIONAL AREA OF SAID ANNULAR FLUID CHAMBER ALONG THE COLUMN, ELONGATED BEARING MEANS MOUNTED ON SAID END SECTIONS OF THE OUTER ASSEMBLY SLIDABLY ENGAGEABLE WITH SAID SLIDE BEARING PORTIONS OF THE COLUMN TO SLIDABLY MOUNT THE OUTER ASSEMBLY THEREON AND SEAL THE FLUID CHAMBER FORMED THEREIN, AND MEANS FOR SUPPLYING FLUID UNDER PRESSURE TO SAID FLUID CHAMBER TO VARY THE VOLUME OF SAID FLUID CHAMBER, THE END SECTION OF THE OUTER ASSEMBLY HAVING THE SMALLER CROSS-SECTIONAL DIMENSION DEFINING A CROSS-SECTIONAL AREA OF THE FLUID CHAMBER WHICH IS LARGER THAN THE CROSS-SECTIONAL AREA DEFINED BY THE END SECTION HAVING THE LARGER CROSS-SECTIONAL DIMENSION WHEREBY, SAID VARIATION IN THE VOLUME OF THE FLUID CHAMBER IS PRODUCED BY RELATIVE MOVEMENT BETWEEN THE COLUMN AND THE OUTER ASSEMBLY THROUGH SUPPLY OF A REDUCED VOLUME OF FLUID BY THE FLUID SUPPLYING MEANS.