Heave compensated dual hoist crane

Patent metadata

Field	Value
Publication number	US-2024286875-A1
Application number	US-202418657072-A
Country	US
Kind code	A1
Filing date	May 7, 2024
Priority date	Apr 5, 2019
Publication date	Aug 29, 2024
Grant date	—

Abstract

A dual hoist crane is provided with a heave compensation system that can be used for both the main and for the auxiliary hoisting assembly. The heave compensation system includes a first set of sheaves for guiding the main hoisting cable and a second set of sheaves for guiding the auxiliary hoisting cable. The heave compensation system is configured to individually lock the first set of sheaves and the second set of sheaves to a heave compensation cylinder, for respectively providing the main hoisting assembly and the auxiliary hoisting assembly with heave compensation.

First claim

What is claimed is:

1 . A crane, the crane comprising:
a crane structure; a boom, the boom having an inner end, a midsection, and an outer end, the boom being pivotable supported by the crane structure such that the boom can be pivoted about a substantially horizontal boom pivot axis; a main hoisting assembly, for lifting and lowering a load, the main hoisting assembly comprising a main hoisting winch and an associated main hoisting cable, and a main load suspension device; and a luffing assembly for pivoting the boom up and down, the luffing assembly comprising:
a luffing winch and an associated luffing cable; and
a gantry comprising a back stay and a back frame, the gantry supporting a luffing cable sheave for guiding the luffing cable from the luffing winch to the outer end of the boom,
wherein the back frame is located between the back stay and the boom, and wherein the back stay and back frame are both at a lower end pivotably mounted to the crane structure, for pivoting about a substantially horizontal back stay pivot axis and back frame pivot axis respectively, and are both at an upper end pivotably connected to each other, and wherein the gantry is a foldable gantry, the backstay comprising a lower frame section and an upper frame section, the lower frame section and the upper frame section being pivotably connected to each other, and wherein the gantry can be lowered by pivoting the lower frame section relative to the upper frame section.

2 . The crane according to claim 1 , wherein the gantry is provided with actuators for pivoting the lower frame section and the upper frame section of the backstay relative to each other, and thus for lowering and raising the gantry.

3 . The crane according to claim 1 , wherein the lower frame section of the back stay and the back frame are both provided with a support structure, the support structures being configured to cooperate to support the back frame when the gantry is in the folded configuration.

4 . The crane according to claim 1 , wherein the luffing winch is mounted to the gantry, near the back frame pivot axis.

5 . The crane according to claim 1 , wherein the luffing assembly comprises a luffing cable guide arm supporting the luffing cable sheave, the guide arm further comprising a boom side sheave, wherein the luffing cable sheave and boom side sheave are spaced relative to each other, for spacing part of the luffing cable at a distance from the back stay and for guiding the luffing cable to the boom.

6 . The crane according to claim 5 , wherein the guide arm is pivotably mounted to the back frame, at the top of the gantry, and is pivotable supported by a guide arm pivot axis, the guide arm pivot axis extending parallel to the boom pivot axis.

7 . The crane according to claim 6 , wherein the guide arm is a triangular construction, when seen in a direction parallel to the guide arm pivot axis, wherein the triangular construction is pivotable supported at a top thereof, and wherein the base of the triangular construction supports the boom side sheave at one end and supports the luffing cable sheave at an opposite end of the triangular construction.

8 . The crane according to claim 7 , the at least one luffing cable being guided from the crane structure over the at least one luffing cable sheave and over the at least one boom side sheave to the boom, wherein the luffing cable guide arm is configured to position the at least one boom side sheave away from the back frame of the gantry such that the at least one luffing cable extends from a position above the top of the gantry to the boom, when the gantry is in the folded configuration.

9 . The crane according to claim 1 , wherein the crane is a dual hoist crane that is provided with an auxiliary hoisting assembly for lifting and lowering a load, the auxiliary hoisting assembly comprising an auxiliary hoisting winch and an associated auxiliary hoisting cable, and an auxiliary load suspension device.

10 . The crane according to claim 9 , wherein the lower frame section of the back stay, is provided with a wire support, the wire support supporting the main hoisting wire and the auxiliary hoisting wire when the gantry is in the folded configuration.

11 . The crane according to claim 10 , wherein the gantry is provided with a dual hoist heave compensation system and wherein the wire support is configured such that the hoisting wires are led into the dual hoist heave compensation system in a vertical direction and parallel to cylinders of the dual hoist heave compensation system, when the gantry is in the folded configuration.

12 . A vessel provided with the crane according to claim 1 .

13 . A method for lowering height of a vessel provided with the crane having the foldable gantry according to claim 1 , the method comprising the steps of:
lowering the boom in a rest position; setting the main hoisting cable under constant tension to thus load the back stay of the gantry; initiating pivoting of the lower frame section of the back stay relative to the upper frame section of the back stay; and paying out the luffing cable to lower the gantry, until the gantry is in a lowered position thereof.

14 . The method according to claim 13 , wherein the step of setting the main hoisting cable under constant tension comprises using a heave compensation system or the hoisting winch associated with the main hoisting cable for setting the hoisting cable under constant tension.

15 . The method according to claim 13 , wherein initiating pivoting of the lower frame section of the back stay relative to the upper frame section of the back stay comprises using an actuator for pivoting the lower frame section of the back stay relative to the upper frame section of the back stay.

16 . The method according to claim 13 , wherein paying out the luffing cable to lower the gantry comprises keeping constant tension in the hoisting cable until the gantry is in its lowered position.

Assignees

• Itrec Bv

Inventors

• Van Veluw Cornelis Martinus
• Lee Wing Sum
• Van Oijen Ken

Classifications

• B66C23/823

  Bracing equipment acting in vertical direction · CPC title

• B66C19/00

  Cranes comprising trolleys or crabs running on fixed or movable bridges or gantries (B66C17/00 takes precedence; base supporting structures with legs B66C5/00; jib cranes B66C23/00) · CPC title

• B66C13/02

  Devices for facilitating retrieval of floating objects, e.g. for recovering crafts from water (handling live-boats B63B; salvaging, or hauling-out on slipways, waterborne vessels B63C; winding mechanism controls B66D1/52) · CPC title

• B66C23/52 Primary

  Floating cranes (floating dredgers E02F) · CPC title