Abstract: A hydraulic locking device for an exoskeleton joint with an extendable and retractable hydraulic cylinder, a tank and a switching valve. The hydraulic cylinder is connected to the tank via a line arrangement and the switching valve is disposed in the line arrangement. The switching valve is switchable between a release position and a blocking position. The hydraulic cylinder is freely movable in the release position of the switching valve, and the switching valve prevents retraction of the hydraulic cylinder in the blocking position. The hydraulic locking device further comprises a housing, and the hydraulic cylinder is a plunger cylinder with a plunger cylinder housing and a plunger piston movably arranged in the plunger cylinder housing, the plunger cylinder being arranged within the housing. Further, an exoskeleton joint having such a hydraulic locking device is disclosed.

Abstract: A flat tube, in particular for a heat exchanger, is provided that has an areal material strip with two mutually opposite first and second side walls which are connected to one another via third and fourth side walls, wherein the third side wall is formed by two sections of the material strip that are laid one against the other in double-layer form, wherein an internal fin is arranged in the interior of the flat tube, which fin, at the end sides, bears against the third side wall and against the fourth side wall, and which fin, between the third side wall and the fourth side wall, is supported alternately against the first side wall and against the second side wall.

Abstract: A flat tube, in particular for a heat exchanger, is provided that has an areal material strip with two mutually opposite first and second side walls which are connected to one another via third and fourth side walls, wherein the third side wall is formed by two sections of the material strip that are laid one against the other in double-layer form, wherein an internal fin is arranged in the interior of the flat tube, which fin, at the end sides, bears against the third side wall and against the fourth side wall, and which fin, between the third side wall and the fourth side wall, is supported alternately against the first side wall and against the second side wall.