Cargo crane, cargo-crane swing prevention method, and cargo conveyance method

Patent metadata

Field	Value
Publication number	US-12358761-B2
Application number	US-202118010136-A
Country	US
Kind code	B2
Filing date	May 14, 2021
Priority date	Jun 22, 2020
Publication date	Jul 15, 2025
Grant date	Jul 15, 2025

Abstract

A cargo crane including an arm turning mechanism that turns a crane arm; an arm luffing mechanism that adjusts the luffing angle; an arm extension and contraction mechanism that adjusts the arm length; and a control device that calculates a trajectory in which a suspended cargo is conveyed, and that controls the mechanisms. The control device calculates the trajectory so as to be a straight line trajectory as viewed from at least the vertical direction; calculates a turning angle θ, a luffing angle φ, and an arm length L so as to cause the trajectory to be the straight line trajectory by using the cargo start position, the cargo target position, a maximum speed v max , a suspended cargo swing cycle T, and a start-up time T 1 ; and controls the mechanisms so as to achieve the calculated turning angle θ, luffing angle φ, and arm length L.

First claim

The invention claimed is:

1. A cargo crane configured to convey a suspended cargo from an arbitrary cargo start position to a cargo target position by a turning motion of a crane arm, the suspended cargo being suspended by a wire provided to an arm distal end portion of the crane arm, the cargo crane comprising:
an arm turning mechanism configured to turn the crane arm;
an arm luffing mechanism configured to adjust a luffing angle of the crane arm;
an arm extension and contraction mechanism configured to adjust an arm length of the crane arm; and
a control device configured to calculate a trajectory in which the suspended cargo is conveyed, and configured to control the arm turning mechanism, the arm luffing mechanism, and the arm extension and contraction mechanism,
wherein the control device is configured to:
calculate the trajectory to be a straight line trajectory as viewed from at least a vertical direction, according to the cargo start position and the cargo target position;
using the cargo start position, the cargo target position, a maximum speed, a suspended cargo swing cycle, and a start-up time, calculate a turning angle of the crane arm, the luffing angle, and the arm length to cause the trajectory to be the straight line trajectory; and
control the arm turning mechanism, the arm luffing mechanism, and the arm extension and contraction mechanism to achieve the turning angle, the luffing angle, and the arm length calculated.

2. The cargo crane according to claim 1 , wherein the control device is configured to perform a calculation to cause a height of the straight line trajectory in the vertical direction to be constant.

3. The cargo crane according to claim 2 , wherein the control device is configured to:
calculate the turning angle from a formula (8) by using a speed of the arm distal end portion calculated from each of formulas (11) to (17); and
when calculating the speed, use the formula (11) at a time when t<T 1 , use the formula (12) at a time when T 1 ≤t<nT, use the formula (13) at a time when nT≤t<nT+T 1 , use the formula (14) at a time when nT+T 1 ≤t<t t −nT−T 1 , use the formula (15) at a time when t t −nT−T 1 ≤t<t t −nT, use the formula (16) at a time when t t −nT≤t<t t −T 1 , and use the formula (17) at a time when t t −T 1 ≤t≤t t :

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Assignees

• Jfe Steel Corp

Inventors

• TAKAKI Yuki
• Yoshinari Yusuke
• Yamaguchi Osamu

Classifications

• B66C13/48 Primary

  Automatic control of crane drives for producing a single or repeated working cycle; Program control · CPC title

• B66C23/88

  Safety gear (for cranes in general B66C15/00; for rope, cable, or chain winding mechanisms B66D1/54) · CPC title

• B66C13/063

  electrical · CPC title

• B66C23/82

  Luffing gear · CPC title

• B66C23/94

  for limiting slewing movements · CPC title