Abstract: An advancing assembly for underground powered shield support having at least one floor skid for supporting the powered shield support, an advancing beam and a substantially perpendicularly arranged lift cylinder for lifting the floor skid relative to the advancing beam during an advancing movement. The lift cylinder has a cylinder foot supported above the advancing beam and a cylinder head buttressed on a bridge and hydraulically displaceable relative to the cylinder foot. In order to improve a powered shield support and in particular the advancing assembly of a powered shield support, the lift cylinder is a double lift cylinder having a first cylinder stage, comprising the cylinder head, and a second cylinder stage, wherein a compression spring is arranged between the cylinder stages.

Abstract: A lift cylinder arrangement is disclosed for a hydraulic support frame for underground mining. The support frame has a lift cylinder for lifting the base shoes during advancing, which is supported on the one hand on a return rod and on the other hand, in a pivoting manner, with an end supporting head to a drawbar connected to the base shoes. In order to allow a simple, rapid and reliable connection between the supporting head and the drawbar, the supporting head is connected to the drawbar by a plug-type locking system comprising two plug-type locking elements, which include first locking notches on the drawbar, and arranged complementarily thereto second locking notches on the supporting head, whereby the plug-type locking elements engage in at least one of the locking notches with clearance.

Abstract: A lift cylinder arrangement is disclosed for a hydraulic support frame for underground mining. The support frame has a lift cylinder for lifting the base shoes during advancing, which is supported on the one hand on a return rod and on the other hand, in a pivoting manner, with an end supporting head to a drawbar connected to the base shoes. In order to allow a simple, rapid and reliable connection between the supporting head and the drawbar, the supporting head is connected to the drawbar by a plug-type locking system comprising two plug-type locking elements, which include first locking notches on the drawbar, and arranged complementarily thereto second locking notches on the supporting head, whereby the plug-type locking elements engage in at least one of the locking notches with clearance.