Hydraulic cylinder that will automatically expunge air and self level

Abstract

A hydraulic cylinder with piston and rod enclosed, that upon receiving air and oil, singularly or along with one or more identical cylinders, from a new, dry, system start up, will, upon extension, when the piston seal passes a predetermined point, stop. With continued pumping from either a manual single or multiple cylinder pump or an electric pump all the identical piston rods will arrive at the predetermined stop and the cylinders will be purged of air and when the manual locks are placed over the extended piston rods, they will stay there and not move up or down, regardless of ambient temperature changes or inadvertent release of the oil. After they are extended the first time all the cylinders will stop at the predetermined point in an even position with each other. The locks and pumps are not shown in this application.

1 . A hydraulic cylinder comprising a cylinder tube with an enclosed bottom end and a threaded hole in said bottom end to which a pressure line carrying fluid from a pressure scource is connected, said cylinder tube having on it's interior, vertical wall, at a predetermined and optional location near the top, a relief hole with a precisely engineered approach and a precisely engineered departure passing thru said interior, vertical wall, and opening into a relief tube attached to, and extending down the vertical exterior of said vertical wall to a point below the bottom of the said cylinder tube, said cylinder tube having in it's interior a single piece piston and rod combined, of the same diameter, with the lower portion serving as the piston, and the upper portion serving as the rod, said lower portion having a groove containing a wear ring, said lower portion has an interior opening, rising from the bottom center of the piston and intersecting with a horizontal opening entering the piston slightly above the said groove containing the wear ring, said outer opening of the horizontal opening, intersecting with a vertical transfer channel on the exterior of the piston rising to a narrowed oil retaining area of the piston, a groove containing a hydraulic seal at the upper edge of said narrowed oil retaining area, said seal causing the single piece piston and rod to extend when supplied with oil from a pressure source. 
     
     
         2 . A hydraulic cylinder as claimed in  claim 1 , with a single piece piston and rod of the same diameter, adjustable to stop at any desired, predetermined point upon receiving fluid. 
     
     
         3 . A hydraulic cylinder as claimed in  claim 2 , that along with one or more identical cylinders, will, upon receiving fluid arrive at a state of complete eveness of extension of all the pistons in the system if all are adjusted to the same predetermined point, regardless of the uneveness of the extension of the pistons enroute. 
     
     
         4 . A hydraulic cylinder as claimed in  claim 1 , that can be adjusted to easily and simply stop at a predetermined point without using complicated and unreliable electrical limit switches and mechanical devices, thereby eliminating over extensions and damaging canvas or other materials on the sides and ends of camping trailers and truck campers and any other collateral damage that may occur to the system it is being used in, or the surrounding area. 
     
     
         5 . A cylinder relief hole, so engineered as to permit a hydraulic seal on a piston, in a cylinder, to pass by thousands of cycles without compromising the seal or the integrity or function of the cylinder.