COMBINED DUAL-ACTION TELESCOPIC HYDRAULIC CYLINDER Russian patent published in 2008 - IPC B66F3/28 B66F9/22 

FIELD: engines and pumps.

SUBSTANCE: hydraulic cylinder includes a coaxial set of piston steps with external and internal cases. One of the steps contains the two-side rod combined with the internal case with its ends having various external diameters, and the piston with various working areas of its sides. Identical cavities of steps are hydraulically connected in pairs forming the combined cavities. Piston cavities are arranged so that to allow arrival to opposite phases corresponding to maximum and minimum their volumes in extreme positions of the hydraulic cylinder. The external case is made executed with one end face bottom accommodating a rigidly fixed end of the two-side rod of a smaller diameter. The piston is made in the form of a sleeve with cylindrical necks and collar and arranged so that to allow enveloping of the two-side rod to form the cavity limited by cylindrical necks. Cylindrical necks and collar are made to interact and to contact with the two-side rod and the external case, respectively, the said contact being sealed. The length of the piston should not be less than the travel of this step of the hydraulic cylinder.

EFFECT: higher efficiency and reliability.

2 cl, 3 dwg