Patent ID: 11919752
Assignee: MANITOWOC CRANE GROUP FRANCE
Field: Handling (Mechanical engineering)
Classification: CPC B | IPC B

Claim 11:
12. A tilting jib crane comprising a tilting jib displaceable in lifting and in lowering by means of a tilting winch integrating a tilt motor driving a drum on which is wound a tilting rope coupled to the tilting jib, the drum being secured in rotation with a locking platen provided with circumferentially distributed locking holes, and further comprising a lock displaceable between:
a release configuration in which the lock is disengaged from the locking platen to authorize the rotation of the drum and thus allow lifting/lowering of the tilting jib; and
a locking configuration in which the lock is engaged inside a locking hole to block the rotation of the drum and thus secure the angular position of the tilting jib;
wherein the locking holes are all oblong arcuate shaped so that the lock is engaged with a circumferential clearance within a locking hole in the locking configuration,
the tilting jib crane further comprising:
a measurement system for measuring a speed parameter representative of an angular speed of displacement of the tilting jib, in lifting or in lowering, and a monitoring/control system connected to the tilt motor and to the measurement system, the monitoring/control system being configured to:
perform a first control of the tilt motor to displace the tilting jib in lifting or in lowering, with a limitation of the speed parameter to a first maximum speed value and limitation of a motor torque of the tilt motor to a first torque limit value, until a given angular position of the tilting jib is reached, in which the lock is aligned with one of the locking holes of the locking platen, said lock occupying the release configuration; and
after a forward displacement of the lock to occupy a locking configuration in which the lock is engaged inside the locking hole on which the lock is aligned, perform a second control of the tilt motor to displace the tilting jib in lowering, with a limitation of the speed parameter to a second maximum speed value, which is lower than the first maximum speed value, and a limitation of the motor torque of the tilt motor to a second torque limit value, which is lower than the first torque limit value, until the speed parameter is zero for a predetermined time period to stop the tilt motor.