I'm trying to imaging the mechanism. The author seems to be inventing terminology for a non-standard mechanism. Start with the "orificio". It seems that this can only refer to where the central channel or conduit (60) "opens" into the "émbolo cilíndrico". It does so in the side (end?) towards the "cilindro de base", AKA "núcleo rotative", which, to be a nucleus, must be the innermost part. So it's not a hollow cylinder that a piston could fit into, it's a solid cylinder that fits inside something and rotates. It has a bearing on it. I wonder if the "émbolo" is a piece with a cylindrical hole that fits over this cylinder. The "cilindro" would look like a piston, but with no longitudinal movement, and the "émbolo" slides up and down on it, like a moving cyinder. The author calls it the "émbolo" because it's the part that moves, putting pressure on the hydraulic fluid. Then the "pistón", with its adjustment screw, is a rod that pushes the "émbolo". Does this make sense?