Abstract: A system for opening and closing a motor vehicle, the flap is swivalably mounted along one of its edge areas at a stationary structural component part about a horizontal swiveling axis. A first drive device and a second drive device act in parallel to more like flap from a closed position into an open position. The first drive device is a non-self-locking drive device, and the second drive device comprises a cylinder filled with a fluid under pressure. An interior of the second drive device is divided by a piston into a first work chamber and a second work chamber, wherein a piston rod of the piston is guided outward through the first work chamber. A valve arrangement in the piston closes a flow connection between the first work chamber and the second work chamber in a stationary operating state of the flap.

Abstract: A system for opening and closing a motor vehicle, the flap is swivalably mounted along one of its edge areas at a stationary structural component part about a horizontal swiveling axis. A first drive device and a second drive device act in parallel to more like flap from a closed position into an open position. The first drive device is a non-self-locking drive device, and the second drive device comprises a cylinder filled with a fluid under pressure. An interior of the second drive device is divided by a piston into a first work chamber and a second work chamber, wherein a piston rod of the piston is guided outward through the first work chamber. A valve arrangement in the piston closes a flow connection between the first work chamber and the second work chamber in a stationary operating state of the flap.

Abstract: A housing having a first housing end and a second housing end, a substantially cylindrical work chamber formed in the housing, a piston which is arranged in the work chamber so as to be displaceable and which divides the work chamber into a first work space near the first housing end and a second work space near the second housing end, a piston rod which is arranged at one side of the piston and which projects through the first work space and is guided out of the work chamber in a sealed manner at the first housing end through a guiding and sealing device, and a valve chamber which is formed in the housing parallel to the work chamber and in which a first valve assembly and a second valve assembly are arranged. The work chamber is always completely filled with a liquid medium and the valve chamber is at least partially filled with a liquid medium.

Abstract: A continuously blockable locking device with a cylindrical housing forming a work chamber, a closed first end and a second end located opposite from the closed end, a piston rod which is guided out of the housing in a sealed manner through the second end so as to be arranged coaxial to the center longitudinal axis by means of a guiding and sealing device, a piston which is arranged at the end of the piston rod situated in the housing and which divides the work chamber into a first work space, through which the piston rod extends, and a second work space, and a housing which is connected to, or can be connected to, the housing and which forms a valve chamber, a first valve assembly and a second valve assembly being arranged therein. The work chamber is always completely filled with a liquid medium and the valve chamber is at least partially filled with a liquid medium.

Abstract: A continuously blockable locking device with a cylindrical housing forming a work chamber, a closed first end and a second end located opposite from the closed end, a piston rod which is guided out of the housing in a sealed manner through the second end so as to be arranged coaxial to the center longitudinal axis by means of a guiding and sealing device, a piston which is arranged at the end of the piston rod situated in the housing and which divides the work chamber into a first work space, through which the piston rod extends, and a second work space, and a housing which is connected to, or can be connected to, the housing and which forms a valve chamber, a first valve assembly and a second valve assembly being arranged therein. The work chamber is always completely filled with a liquid medium and the valve chamber is at least partially filled with a liquid medium.

Abstract: Presented is a piston-cylinder unit that includes a closed first end, a cylinder, a sealing device, and a piston installed in the cylinder with freedom to slide back and forth. The piston divides the cylinder into a first space at the closed end and a second space at the end opposite the closed end. The piston-cylinder unit further includes a piston rod attached to one side of the piston. The piston rod projects through the second space and is guided out of the cylinder concentrically with the longitudinal center axis of the cylinder at the second end, opposite the first end, in a sealed manner through the sealing device. The piston-cylinder unit further includes a ferrofluid, and at least one magnetic element that has a magnetic field, which cooperates with the ferrofluid present in the cylinder.

Abstract: A gas spring includes a center longitudinal axis and a closed first end, a cylinder filled with gas under pressure, a piston displaceably arranged in the cylinder and dividing the cylinder into a first work chamber near the closed end and a second work chamber remote of the closed end, a piston rod passing through the second work chamber and guided out of the cylinder through a guiding and sealing device, and a mechanical blocking device whose action depends upon the internal pressure. The piston has a piston chamber connected to the outside of the cylinder. A first safety element and a second safety element form the mechanical blocking device. The first safety element connects the first work chamber to the outside via the piston chamber when the pressure in the cylinder is too low and brings the second safety element into contact with the inner wall of the cylinder.

Abstract: A system for opening and closing a motor vehicle, the flap is swivalably mounted along one of its edge areas at a stationary structural component part about a horizontal swiveling axis. A first drive device and a second drive device act in parallel to more like flap from a closed position into an open position. The first drive device is a non-self-locking drive device, and the second drive device comprises a cylinder filled with a fluid under pressure. An interior of the second drive device is divided by a piston into a first work chamber and a second work chamber, wherein a piston rod of the piston is guided outward through the first work chamber. A valve arrangement in the piston closes a flow connection between the first work chamber and the second work chamber in a stationary operating state of the flap.

Abstract: A novel gas injection valve for injecting discrete charges of gas into a mobile phase or carrier stream is provided. Injection valves of the invention comprise a plurality of microvalves capable of receiving gas at different pressures and emitting discrete charges of gas at approximately the same pressure. The invention further provides for parallel injection valve arrays capable of injecting multiple samples substantially simultaneously and a method of injecting discrete gas samples at a controlled pressure to a high-resolution gas chromatograph.