Heavy lift crane

Patent metadata

Field	Value
Publication number	US-12515924-B2
Application number	US-202118013382-A
Country	US
Kind code	B2
Filing date	Jun 29, 2021
Priority date	Jun 29, 2020
Publication date	Jan 6, 2026
Grant date	Jan 6, 2026

Abstract

A crane for use on an offshore vessel is provided with a boom restrainer, wherein the boom restrainer is a hydro-pneumatic boom restrainer, for reducing upward pivoting of the boom, when the boom is in the top zone, wherein the boom restrainer includes: multiple hydraulic cylinders, each having a hydraulic circuit and a cylinder rod with a cylinder head, wherein the cylinders are mounted on the crane structure with the cylinder heads directed towards the boom of the crane, preferably are mounted on a stay of the crane structure, a catcher for each hydraulic cylinder, wherein each catcher is mounted on the boom and is configured for receiving the cylinder head of the corresponding hydraulic cylinder, and to lock the cylinder head, preferably pivotable locks the cylinder head, relative to the boom, when the boom pivots upwards in the top zone; a gas buffer for each hydraulic cylinder, wherein each gas buffer is mounted to the corresponding hydraulic cylinder, and is connected to the hydraulic circuit of the corresponding hydraulic cylinder via a medium separator, wherein the gas buffer forces the hydraulic cylinder in an extended position, and wherein the volume ratio between the hydraulic cylinder and the gas buffer is such that the hydraulic cylinder acts as a progressive spring, e.g. the gas buffers each have a size in the range of 1000-1400 litre, for example 1200 litre and the hydraulic cylinders each have a size in the range of 800-1000 litre, for example 900 litre, and preferably the ratio between the volume of the gas buffer and the volume of the associated hydraulic cylinder is 4:3.

First claim

The invention claimed is:

1 . A heavy lift crane for use on a vessel, the crane comprising:
a base structure, wherein the base structure is adapted to be mounted to, or formed integral with, the vessel; a crane structure, wherein the crane structure is rotationally supported by the base structure for rotation of the crane structure relative to the base structure about a vertical rotation axis; a boom, wherein the boom comprises a longitudinal axis, a pivot end, a mid-section, and a hoisting end opposite the pivot end, wherein the boom is supported by the crane structure, so that the boom can rotate about the vertical rotation axis, and wherein the pivot end of the boom is pivotably connected to the crane structure, so that the boom can pivot up and down about a horizontal boom pivot axis; a boom luffing assembly, wherein the boom luffing assembly comprises a boom luffing wire and a boom luffing winch, wherein the boom luffing wire extends from the boom luffing winch to the hoisting end of the boom, for pivoting the boom upward and downward about the boom pivot axis, and for supporting the boom in a hoisting position relative to the crane structure, wherein the boom luffing assembly is configured to pivot the boom in a working zone that comprises the range of boom positions that allow for controlled lifting of a load with the crane, and that is at a top end thereof limited by a maximum operating boom angle, and wherein the boom luffing assembly is configured to pivot the boom into a top zone, wherein the top zone at least covers an angle of 16 degrees with the vertical rotation axis of the crane, and wherein the top zone overlaps with the working zone of the crane; a hoisting assembly for hoisting a load, wherein the hoisting assembly comprises a hoisting winch, a hoisting wire, and a load suspension device, wherein the hoisting wire extends from the hoisting winch via a hoisting wire guide, located at the hoisting end of the boom, to the load suspension device; and a hydro-pneumatic boom restrainer, that is constructed and positioned on the crane to engage the crane boom when the boom is pivoted into the top zone for reducing upward pivoting of the boom, when the boom is in the top zone, wherein the boom restrainer comprises:
multiple hydraulic cylinders, each having a hydraulic circuit, comprising one or more valves that can be switched between a free flow configuration and a throttle configuration, and a cylinder rod with a cylinder head, wherein the hydraulic cylinders are mounted on the crane structure with the cylinder heads directed towards the boom of the crane;
a catcher for each hydraulic cylinder, wherein each catcher is mounted on the boom and is configured for receiving the cylinder head of the corresponding hydraulic cylinder, and to lock the cylinder head relative to the boom, when the boom pivots upwards into the top zone and the catcher engages the cylinder head, while the boom is still in the top zone;
a gas buffer for each hydraulic cylinder, wherein each gas buffer is mounted to the corresponding hydraulic cylinder, and is connected to the hydraulic circuit of the corresponding hydraulic cylinder via a medium separator, wherein the gas buffer forces the hydraulic cylinder in an extended position, and wherein the volume ratio between the hydraulic cylinder and the gas buffer is such that the hydraulic cylinder acts as a progressive spring; and
a control system; comprising one or more sensors to monitor loss of a load, wherein the one or more sensors are mounted on the boom restrainer and/or on the crane and are linked to the control system,
wherein the boom restrainer can be switched between: a passive modus, in which the boom restrainer allows for movement of the cylinder rods in the respective hydraulic cylinders, and thus allows for movement of the boom relative to the crane structure or a mast of the crane in the top zone, and an active modus, in which the boom restrainer slows down and blocks movement of the cylinder rods in the respective hydraulic cylinders, and thus slows down and blocks movement of the boom relative to the crane structure or the mast of the crane in the top zone, and wherein the control system is configured to operate one or more valves in the hydraulic circuit of the respective hydraulic cylinders and to switch these one or more valves from the free flow configuration into the throttle configuration when the one or more sensors signal the control system a loss of the load and/or roll of the vessel, and to thus switch the boom restrainer from the passive modus into the active modus when the one or more sensors register a loss of load of the vessel.

2 . The heavy lift crane according to claim 1 , wherein in the top zone the angle of the boom with the vertical rotation axis of the crane is in the range of 0-30 degrees, and
wherein the boom of the crane can be pivoted in the working zone, wherein in the working zone the angle of the boom with the vertical rotation axis of the crane is between 20 degrees and 100 degrees, and wherein the top zone overlaps with the working zone.

3 . The heavy lift crane according to claim 1 , further comprising a boom stop, wherein the boom stop is configured to block movement of the boom at a safety angle, the safety angle being the maximum height wherein the boom can be pivoted, and
wherein the boom stop comprises a crush zone, configured to slow down and stop the boom by controlled deformation.

4 . The heavy lift crane according to claim 3 , wherein the boom stop comprises a bumper that engages the boom prior to the boom reaching a maximum working angle, to resiliently receive the boom and prevent the boom from coming to a hard stop against the boom stop.

5 . The heavy lift crane according to claim 4 , wherein the boom stop comprises sensors that are linked to the control system, and wherein the control system is configured to block the luffing system from further lifting the boom, thus preventing the luffing system from pivoting the boom beyond the maximum working angle.

6 . The heavy lift crane according to claim 1 , wherein the boom restrainer comprises a crush zone, configured to slow down and stop the boom by controlled deformation, when the boom moves above a maximum pivot speed.

7 . The heavy lift crane according to claim 1 , wherein the hydraulic circuits of the multiple hydraulic cylinders are coupled, to equalize load differences between the hydraulic cylinders.

8 . The heavy lift crane according to claim 1 , wherein the hydraulic cylinders are compressed when the boom is pivoted upwards in the top zone, and the hydraulic cylinders tension the luffing wires.

9 . The heavy lift crane according to claim 1 , wherein the cylinder rods of the boom restrainer are fully extended when they engage the boom and the boom is at an angle of 35 degrees with the vertical rotation axis.

10 . The heavy lift crane according to claim 1 , wherein the cylinder rods of the boom restrainer are fully retracted when the boom is at an angle of 15 degrees with the vertical rotation axis.

11 . The heavy lift crane according to claim 1 , wherein the boom is an A-frame boom.

12 . The heavy lift crane according to claim 1 , wherein the boom at a base end comprises a box frame, and the catchers for the hydraulic cylinders are mounted on the box frame.

13 . The heavy lift crane according to claim 1 , wherein the hydraulic cylinders are pivotable supported, such that the hydraulic cylinders can pivot about a horizontal axis relative to the crane structure.

14 . The heavy lift crane according to claim 1 , wherein the crane structure comprises a stay, and

Assignees

• Itrec Bv

Inventors

• Wijning Diederick Bernardus
• Romeijn Eric
• Roodenburg Joop

Classifications

• B66C2700/084

  Protection measures · CPC title

• B66C23/92 Primary

  Snubbers or dashpots for preventing backwards swinging of jibs, e.g. in the event of cable or tackle breakage · CPC title

• B66C23/905

  electrical · CPC title

• B66C23/58

  arranged to carry out a desired sequence of operations automatically, e.g. hoisting followed by luffing and slewing · CPC title

• Y02E10/727

  Offshore wind turbines · CPC title