Bridge crane
The object of the invention is a bridge crane, which comprises a main girder, which is fitted to travel supported by end carriages essentially at both ends and which bridge crane further comprises a hoisting trolley traveling supported by the main girder and a rope drum mounted on bearings to rotate in an essentially stationary position, from which rope drum the hoisting rope is guided to a hook traveling along with the hoisting trolley. The hoisting rope is supported from below for at least a part of its essentially horizontal section.
1. A bridge crane, comprising:
a main girder extending along an axis and supported by end carriages essentially at both ends of the axis of the main girder such that the main girder travels along a direction perpendicular to said axis;
a hoisting trolley configured to travel along the axis and supported by the main girder:
a pair of rope channels positioned on top of the main girder and extending parallel to the axis of extension of the main girder: and
a rope drum mounted on bearings to rotate in an essentially stationary position, from which rope drum a hoisting rope is guided to a hook traveling along with the hoisting trolley, and which hoisting rope is supported from below by the pair of rope channels for at least a part of an essentially horizontal section of the hoisting rope.
2. Bridge crane according to claim 1 , wherein each of the pair of rope channels includes a slide lining, which is placed under the hoisting rope and is closed from above.
3. Bridge crane according to claim 2 , wherein the slide lining is of plate-like plastic or consists of rollers mounted on bearings.
4. Bridge crane according to claim 3 , wherein the rope drum is mounted to the main girder on bearings such that the rope drum rotates around an axis parallel to the axis of extension of the main girder.
5. Bridge crane according to claim 3 , further comprising:
at least one guide pulley in connection with the main girder for guiding passage of the hoisting rope when the hoisting rope discharges from the rope drum and when the hoisting rope coils onto the rope drum, the at least one guide pulley having an axis of rotation perpendicular to the axis of rotation of the rope drum.
6. Bridge crane according to claim 2 , wherein the slide lining is of plate-like plastic or consists of rollers mounted on bearings.
7. Bridge crane according to claim 2 , wherein the rope drum is mounted to the main girder on bearings such that the rope drum rotates around an axis parallel to the axis of extension of the main girder.
8. Bridge crane according to claim 2 , further comprising:
at least one guide pulley in connection with the main girder for guiding passage of the hoisting rope when the hoisting rope discharges from the rope drum and when the hoisting rope coils onto the rope drum, the at least one guide pulley having an axis of rotation perpendicular to the axis of rotation of the rope drum.
9. Bridge crane according to claim 1 , wherein the rope drum is mounted to the main girder on bearings such that the rope drum rotates around an axis parallel to the axis of extension of the main girder.
10. Bridge crane according to claim 9 , further comprising:
at least one guide pulley in connection with the main girder for guiding passage of the hoisting rope when the hoisting rope discharges from the rope drum and when the hoisting rope coils onto the rope drum, the at least one guide pulley having an axis of rotation perpendicular to the axis of rotation of the rope drum.
11. Bridge crane according to claim 1 , further comprising:
at least one guide pulley in connection with the main girder for guiding passage of the hoisting rope when the hoisting rope discharges from the rope drum and when the hoisting rope coils onto the rope drum, the at least one guide pulley having an axis of rotation perpendicular to the axis of rotation of the rope drum.
12. Bridge crane according to claim 1 , wherein a top part of the hoisting trolley comprises diverting pulleys mounted on bearings for guiding the hoisting rope from on top of the main girder to the lifting hook and from the lifting hook back to on top of the main girder and also for compensating the rope forces of the hoisting rope in the hoisting trolley, the diverting pulleys having an axis of rotation perpendicular to the axis of extension of the main girder.
13. Bridge crane according to claim 12 , wherein one of the pair of rope channels includes an aperture such that a part of an outer rim of the diverting pulleys in the hoisting trolley is inside the rope channel.
14. Bridge crane according to claim 13 , wherein the hoisting trolley comprises a guide means having a free end which is fitted to move in the rope channel through the aperture and to lift the hoisting rope from on top of a slide lining within the rope channel to a height of a rope grooves of the diverting pulleys when the hoisting trolley moves.
15. Bridge crane according to claim 1 , wherein the rope forces acting in the hoisting rope are compensated in a guide trolley that is in connection with the rope drum in at least one of the following ways: by fixing a free end of the hoisting rope to the guide trolley; by guiding a free end of the hoisting rope via a second diverting pulley on the guide trolley back to the rope drum; by the aid of a screw means fixed to the guide trolley.
16. Bridge crane according to claim 1 , wherein the hoisting trolley includes a pair of legs extending in a direction perpendicular to the axis of extension of the main girder, a bottom end of each of the legs of the hoisting trolley comprises an extension means for fixing bottom parts of the legs, said parts being of different heights, to the hoisting trolley for fitting the height of the hoisting trolley to be suited to main girders of different heights.