Dual-valve security unit for hydraulic cylinders

A security double-acting hydraulic cylinder, comprising:

• a cylinder body;
• a rod;
• a piston that compartmentalizes the cylinder body into a bottom-side chamber and a rod-side chamber, said chambers each communicating with a specific hydraulic conduit allowing the entry or exit of fluid into or out of the chamber in question;
• and a security unit comprising:
• two isolating devices, each adapted to be mounted in one of the hydraulic conduits, each of the isolating devices adapted to supply one of said chambers of the cylinder, and each comprising a primary valve and a secondary valve, the primary valve being closest to the chamber in question, both passing in the same direction corresponding to the entry of fluid into the chamber in question and arranged one after the other in series;
• wherein the primary valve and the secondary valve of each of said isolating devices are ball-check valves, comprising a seat and a ball;
• wherein each of said isolating devices further includes:
• an independent sliding rod, arranged longitudinally and inserted between the balls of the primary and secondary valves, but not connected thereto, and able to slide toward each of said balls so as to press by one end thereof against the ball located in front, and
• a guide element for the sliding rod that provides guiding of the sliding rod while the sliding rod is sliding;
• and wherein, in each of said isolating devices, the length of the rod is provided to be short enough not to be able to be in contact simultaneously with both of the balls bearing on their respective seats when the two primary and secondary valves are closed;
• but long enough that the opening command of the secondary valve causes, through the movement of the ball thereof that pushes the corresponding end of the sliding rod, the guided sliding of the sliding rod toward the primary valve and causes the opening of the primary valve the ball whereof is pushed by the other end of the sliding rod,
• and wherein, in at least one of the isolating devices, the material of the balls or the material of the seats is different in the primary valve with respect to the secondary valve.

A series-connected dual-valve security unit that ensures, by locking the hydraulic flow, the holding in position of the rod of a double-acting hydraulic cylinder comprising a cylinder body, compartmentalized by a movable piston supporting said rod, into a bottom-side chamber and rod-side chamber, said chambers each communicating with a specific hydraulic conduit allowing the entry or exit of fluid into or out of the chamber in question, said security unit comprising:

• two isolating devices, each adapted to be mounted in one of the hydraulic conduits, each of the isolating devices adapted to supply one of said chambers of the cylinder, and each comprising a primary valve and a secondary valve, the primary valve being closest to the chamber in question, both passing in the same direction corresponding to the entry of fluid into the chamber in question and arranged one after the other in series;
• wherein the primary valve and the secondary valve of each of said isolating devices are ball-check valves, comprising a seat and a ball;
• wherein each of said isolating devices further includes:
• an independent sliding rod, arranged longitudinally and inserted between the balls of the primary and secondary valves, but not connected thereto, and able to slide toward each of said balls so as to press by one end thereof against the ball located in front, and
• a guide element for the sliding rod that provides guiding of the sliding rod while the sliding rod is sliding;
• and wherein, in each of said isolating devices, the length of the rod is provided to be short enough not to be able to be in contact simultaneously with both of the balls bearing on their respective seats when the two primary and secondary valves are closed;
• but long enough that the opening command of the secondary valve causes, through the movement of the ball thereof that pushes the corresponding end of the sliding rod, the guided sliding of the sliding rod toward the primary valve and causes the opening of the primary valve the ball whereof is pushed by the other end of the sliding rod,
• and wherein the guide element is a substantially cylindrical guide support in which the sliding rod is mounted, which slides in a guided manner in a bore provided for the ball of the primary valve;
• and wherein said bore or the guide support includes at least one longitudinal slot allowing the passage of the hydraulic fluid despite the presence of the sliding rod and the guide support in the bore.

A series-connected dual-valve security unit that ensures, by locking the hydraulic flow, the holding in position of the rod of a double-acting hydraulic cylinder comprising a cylinder body, compartmentalized by a movable piston supporting said rod, into a bottom-side chamber and rod-side chamber, said chambers each communicating with a specific hydraulic conduit allowing the entry or exit of fluid into or out of the chamber in question, said security unit comprising:

• two isolating devices, each adapted to be mounted in one of the hydraulic conduits, each of the isolating devices adapted to supply one of said chambers of the cylinder, and each comprising a primary valve and a secondary valve, the primary valve being closest to the chamber in question, both passing in the same direction corresponding to the entry of fluid into the chamber in question and arranged one after the other in series;
• at least one magnetized part that attracts polluting metal particles that may be present in the hydraulic fluid;
• wherein the primary valve and the secondary valve of each of said isolating devices are ball-check valves, comprising a seat and a ball;
• wherein each of said isolating devices further includes:
• an independent sliding rod, arranged longitudinally and inserted between the balls of the primary and secondary valves, but not connected thereto, and able to slide toward each of said balls so as to press by one end thereof against the ball located in front, and
• a guide element for the sliding rod that provides guiding of the sliding rod while the sliding rod is sliding;
• and wherein, in each of said isolating devices, the length of the rod is provided to be short enough not to be able to be in contact simultaneously with both of the balls bearing on their respective seats when the two primary and secondary valves are closed;
• but long enough that the opening command of the secondary valve causes, through the movement of the ball thereof that pushes the corresponding end of the sliding rod, the guided sliding of the sliding rod toward the primary valve and causes the opening of the primary valve the ball whereof is pushed by the other end of the sliding rod.