[0001] The invention relates to a hoisting crane, comprising a crane housing which can be
slewed on a rotary slewing ring, a jib hingedly connected to the bottom part of said
crane housing, luffing means in order to luff the jib in and out, a hoisting drum
with drive motor fitted in or on the housing, and a hoisting cable which is to be
wound on or off the hoisting drum and which runs over guide means at the top side
of the crane housing and guide means at the free end of the jib.
[0002] Such cranes (pedestal cranes) are commonly used on ships to load mixed cargo and
containers into the holds and to unload them from the holds. The problem of known
cranes of this type is that, when the jib is in the fully luffed-in position, a vertical
position of the jib is impossible, because the presence of the crane housing prevents
this. The hoisting apparatus suspended from the hoisting cable - usually a hoisting
hook or spreader - will in this jib position therefore be at a horizontal distance
which is not negligible relative to the crane housing, so that the mixed cargo cannot
be placed directly below the crane housing in the holds of the ship. This leads to
loss of hold space.
[0003] The object of the invention is to eliminate this disadvantage, and to this end the
jib is designed as a lattice which is U-shaped in cross-section, and which accommodates
a part of the crane housing in the fully luffed-in position, while the luffing means
comprise at least one tension cylinder.
[0004] The invention will now be explained with reference to the figures, in which an example
of an embodiment is shown.
Figure 1 shows a perspective view of the hoisting crane of which the jib is luffed
out.
Figure 2 shows a perspective view of the same crane, but in this case with the jib
fully luffed in.
Figure 3 shows a side view of the crane according to Figures 1 and 2 in which the
jib is luffed in.
[0005] The pedestal crane shown comprises a crane housing 1 and a jib 3 hingedly connected
thereto at 2.
[0006] The housing 1 contains a motor-driven winch drum 8 on which a part of a hoisting
cable 6 is wound. This hoisting cable forms a tackle and runs over tackle blocks 7
at the top side of the housing 1 and tackle blocks 8 at the free end of the jib 3
to a hoist hook 9 or other hoisting apparatus.
[0007] Two hydraulic tension cylinders 10 are connected at 11 hingedly to the crane housing
1 and at 12 hingedly to the jib 3, in order to luff the jib in and out.
[0008] The jib 3 is constructed from a lattice and is U-shaped in cross-section.
[0009] As can be seen from Figures 2 and 3, in the fully luffed-in position of the jib a
part of the crane housing falls within the U-shaped jib in the form of a lattice.
[0010] Apart from the U-shape of the jib, the design of the luffing means as tension cylinders
10 (instead of pressure cylinders) is also important for reaching of the vertical
position of the jib in the fully luffed-in position thereof. The tension cylinders
have a small rotary cylinder radius during the luffing in and out of the jib.
[0011] Figure 3 shows that the part of the hoisting cable 6 extending between the hoisting
hook 9 and the tackle block 8 runs at a short distance from the housing, so that piece
goods can be placed and lifted below the crane housing 1. In the case of cranes in
which the jib stands at an angle in the fully luffed-in position, the above-mentioned
part of the hoisting cable with hook thus lies relatively far from the crane housing,
so that the cargo cannot be placed directly below the crane housing. A considerable
gain in loading capacity is achieved by means of the invention.
1.Hoisting crane, comprising a crane housing which can be slewed on a rotary slewing
ring, a jib hingedly connected to the bottom part of said crane housing, luffing means
in order to luff the jib in and out, a hoisting drum with drive motor fitted in or
on the housing, and a hoisting cable which is to be wound on or off the hoisting drum
and which runs over guide means at the top side of the crane housing and guide means
at the free end of the jib, characterized in that the jib is designed as a lattice
which is U-shaped in cross-section, and which accommodates a part of the crane housing
in the fully luffed-in position, and in that the luffing means comprise at least one
tension cylinder.
