Abstract: The disclosure relates to a mobile crane, in particular an rough terrain crane, comprising a boom mounted so as to be pivotable about a horizontal pivot axis, a hydraulic luffing cylinder by means of which the boom can be luffed up and down about the pivot axis, a hydraulic control block for controlling the luffing cylinder and a first safety valve which is connected between the control block and the luffing cylinder and is configured to seal off a load-bearing cylinder chamber of the luffing cylinder in a blocking position. According to the disclosure, the crane further comprises a second safety valve, which is connected in series between the first safety valve and the control block and is configured to seal off the load-bearing cylinder chamber of the luffing cylinder in a blocking position.

Abstract: The disclosure relates to a hydraulic system for pressure supply of a hydraulic actuator, comprising a double-acting hydraulic cylinder having two pressure chambers, and a rapid traverse device integrated into a valve unit and configured to hydraulically interconnect the two pressure chambers in a rapid traverse mode and hydraulically separate the two pressure chambers in a normal traverse mode. The valve unit connects to the pressure chambers via first and second connections and comprises a third connection for applying pressure via a hydraulic pump. A displaceably mounted shift piston separates the first and second connections in normal traverse position and connects them, separated from the third connection, in rapid traverse position. The valve unit integrates a preload device having a switchable preload element configured to separate the third connection from the second connection in a locking position, thereby locking the pressure chamber connected to the second connection towards the outside.

Abstract: The disclosure relates to a driving apparatus for a mobile crane comprising an internal combustion engine, an electric machine, and a transfer case for selectively distributing power outputted to the transfer case to a driving mechanism, and to a pump arrangement for performing crane operation, wherein the internal combustion engine cooperates with an input shaft of the transfer case that cooperates with the driving mechanism, the electric machine cooperates with an intermediate shaft of the transfer case, and the pump arrangement cooperates with an output shaft of the transfer case. The driving apparatus comprises a first clutch arranged between the input and intermediate shafts for coupling them to each other or decoupling them from each other as required, and a second clutch arranged between the intermediate and output shafts for coupling them to each other or decoupling them from each other as required.

Abstract: The disclosure relates to a mobile crane, in particular an rough terrain crane, comprising a boom mounted so as to be pivotable about a horizontal pivot axis, a hydraulic luffing cylinder by means of which the boom can be luffed up and down about the pivot axis, a hydraulic control block for controlling the luffing cylinder and a first safety valve which is connected between the control block and the luffing cylinder and is configured to seal off a load-bearing cylinder chamber of the luffing cylinder in a blocking position. According to the disclosure, the crane further comprises a second safety valve, which is connected in series between the first safety valve and the control block and is configured to seal off the load-bearing cylinder chamber of the luffing cylinder in a blocking position.