| 主权项 |
1. A hydro pneumatic counterweighted lifting system for elevating vertically cargo loads, comprising:
a hydro-pneumatic, double-acting, triple-chamber actuator using hydraulic fluid and gas to reciprocate a load; said actuator mounted vertically on a structural base; said actuator comprising: an outer cylinder vertically mounted on said structural base; an outer piston reciprocating inside the bore of said outer cylinder, said outer piston comprising a piston rod and a piston head, said piston head reciprocating inside the bore of said outer cylinder, said piston rod reciprocating in and out of the top end of said outer cylinder, said outer piston reciprocating said load as said piston rod reciprocates in and out of said outer cylinder; an inner cylinder affixed to the structural base of said actuator and concentric with said outer cylinder; an inner piston affixed at its upper end to the top of said outer piston and concentric with said outer piston, said inner piston comprising at its other end a piston head, said piston head comprising a first face surface, said inner piston reciprocating inside a bore of said inner cylinder; a cylinder head affixed to the upper end of said outer cylinder, said piston rod sliding in a bore of said cylinder head; wherein said structural base comprises an end cap attached to the bottom of said outer cylinder; said actuator further comprising three functional chambers, said chambers comprising: a first hydraulic chamber enclosed inside the bore of said inner cylinder beneath said inner piston first face surface, said first chamber having a hydraulic UP port connecting said first chamber to a first utility port of a hydraulic pump, said first chamber, when hydraulically pressurized, forcing said actuator to extend up by applying pressure on said first face surface of said inner piston; said first chamber having a circular shaped effective hydraulic area determined by the bore diameter of said inner cylinder, said first chamber effective area sized to provide, at full operating hydraulic pressure, an upward force equal to about half the difference between the maximum cargo load up and the minimum cargo load down; a second hydraulic chamber contained between the bore diameter of said outer cylinder and the outer diameter of said outer piston rod, said second chamber comprising a hydraulic DOWN port connecting said second chamber to a second utility port of said hydraulic pump, said second chamber, when hydraulically pressurized, forcing said actuator to retract down by applying hydraulic pressure on said outer piston; said second chamber having an annular shape hydraulic effective area, said annular shape contained between the bore diameter of said outer cylinder and the outer diameter of said outer piston rod, said second chamber effective area sized to provide, at full operating hydraulic pressure, a downward force equal to about half the difference between the maximum cargo load up and the minimum cargo load down; a third counterweight chamber contained between the bore diameter of said outer cylinder and the bore diameter of said inner cylinder, said third counterweight chamber comprising a counterweight port connecting said third counterweight chamber to at least one pressure vessel, said third counterweight chamber constantly charged with pressurized gas, providing a consistent extension force up; said third counterweight chamber having an annular shaped effective area, said annular shaped effective area contained between the bore diameter of said outer cylinder and the bore diameter of said inner cylinder, said third chamber effective area sized to provide said consistent extension force up, said force about equal to the cumulative weight of the unloaded moving parts of the lifting system plus half the difference between the maximum cargo load up and the minimum cargo load down, said force calculated at the minimum operating pressure in said third chamber; said actuator further comprising sealing means to prevent leakage of the hydraulic fluids or the pressurized gas out of said chambers; said actuator designed to automatically circulate the hydraulic fluid in and out of said hydraulic chambers during normal operation in order to bleed entrapped air, said automatic bleeding accomplished by contracting to minimum the volume of hydraulic fluid in each hydraulic chamber during the course of every duty cycle; said first hydraulic chamber decreasing its volume as said inner piston is sliding down into said inner cylinder during downstroke retraction, flushing out all hydraulic fluid and any entrapped air contained in said first hydraulic chamber, except for a small percentage, into the hydraulic system, thereby bleeding out any entrapped air from said first hydraulic chamber during every duty cycle; and said second hydraulic chamber decreasing its volume as said outer piston is sliding up in said outer cylinder during upstroke extension, flushing out all hydraulic fluid and any entrapped air contained in said second hydraulic chamber, except for a small percentage, into the hydraulic system, thereby bleeding out any entrapped air from said second hydraulic chamber during every duty cycle. |
