Abstract: A coupling device includes a first half and a second half adapted to be connected to each other. The first half has a body housing a front chamber and a rear chamber separated by a first element and a second element slidably inserted in a bore provided in the first element. The bore forms an inner cavity in fluid communication with the front chamber and communicating with the rear chamber via a first through-hole provided in the first element. The cavity is sealed from the rear chamber and in that upon connection of the coupling device the second element is longitudinally moved on that a second through-hole provided in said second element comes in fluid communication with the first through-hole thereby providing a fluid communication between the two chambers via the cavity.

Abstract: A coupling device includes a first half and a second half adapted to be connected to each other. The first half has a body housing a front chamber and a rear chamber separated by a first element and a second element slidably inserted in a bore provided in the first element. The bore forms an inner cavity in fluid communication with the front chamber and communicating with the rear chamber via a first through-hole provided in the first element. The cavity is sealed from the rear chamber and in that upon connection of the coupling device the second element is longitudinally moved on that a second through-hole provided in said second element comes in fluid communication with the first through-hole thereby providing a fluid communication between the two chambers via the cavity.

Abstract: A hydraulic accumulator including a fluid chamber and a displaceable piston that is connected to a piston position-measuring means is disclosed. Embodiments of the hydraulic accumulator can provide a device that measures the available fluid volume in the accumulator. In embodiments, the displaceable part of the piston may separate fluid volume from gas volume, and may be connected to a wire that runs through the fluid volume and exits the outside of the accumulator through a sealed opening. Further, in embodiments, the wire may be led over pulleys and through a hollow member connected to the accumulator. The position of an associated metallic core member can be electrically monitored to provide position and fluid volume information.