Abstract: According to an illustrative example of this invention, a gas spring is incorporated into a tennis racket. This gas spring is connected with some of the strings such as to maintain a predetermined tension within the strings irrespective of possible elongation of the strings during operation.

Abstract: In an illustrative example, an oscillation damper for damping the steering movement of the handle bar of a motorcycle comprises a cylinder and a piston rod axially movable with respect to the cylinder. A damping piston is provided at the inner end of the piston rod and divides the cavity within the cylinder into two working chambers. These working chambers are interconnected by at least one axial bore through the piston. Valve discs are provided on both axial end faces of the piston. These valve discs are fixed to the piston in their respective central areas. Circumferential areas of the valve discs define circumferential gaps with the respective end faces. In response to the velocity of axial relative movement of the piston rod with respect to the cylinder the circumferential areas of respective valve discs are approached to the respective end faces. So the damping resistance is increased.

Abstract: In a belt drive, a tensioning roller acts onto a section of a belt. The tensioning roller is biased along a tensioning roller movement path such as to provide a tension of the belt. The tension of the belt is responsive to the driving direction of the belt. A higher tension occurs in a normal driving direction of the belt, and a lower tension occurs in a reverse driving direction of the belt. In the reverse driving direction of the belt there is a risk of disengagement between the belt and respective belt pulleys. A damper is provided for damping the movement of the tensioning roller along the tensioning roller movement path. In order to prevent disengagement of the belt and the respective belt pulleys, the damper is locked when a reverse driving direction occurs and/or when operational conditions occur under which there is a likelihood of the reverse driving direction to occur.

Abstract: A service car for storing and making available tools, accessories and the like comprises a travelling base. At least one column extends upwards from said travelling base. At least one platform is vertically movable along the column. A balancing gas spring is provided within the column. This balancing gas spring acts onto the platform opposite to the action of gravity.

Abstract: A shock absorber comprises a cylinder and a piston rod passing through at least one end of the cylinder. A piston unit is mounted on the piston rod and divides the cavity within the cylinder into two working chambers. A damping fluid is contained within the cylinder. The working chambers are interconnected across the piston unit by first and second branch flow passages arranged in parallel. First and second flow valves are associated with these first and second flow passages, respectively, and operate to dampen movement of the piston rod in at least one direction in dependency on the velocity of movement. The first branch passage flow valve is normally open and closes only when a predetermined velocity of movement is exceeded. The second branch passage flow valve is normally closed and opens only when the pressure differential between the working chambers exceeds a predetermined value. Closing of the first branch passage flow valve increases the damping effect.

Abstract: A damping arrangement for the tub assembly of a washing machine and the like in which a piston mounted on a piston rod in the cavity of a cylinder axially separates two compartments of the cavity and is formed with restricted throttling passages connecting the compartments. The piston may be by-passed by a bore in the piston rod having respective orifices in the two compartments, one orifice being capable of being blocked by an inert mass mounted on the piston rod in one of the compartments for oscillation at the end of a spring. Movement of the inert mass away from a rest position toward which it is normally biased by the spring is limited by a secondary hydraulic damper to prevent operating noise and reduce premature wear.