Crane

Patent metadata

Field	Value
Publication number	US-11787668-B2
Application number	US-201916978990-A
Country	US
Kind code	B2
Filing date	Mar 15, 2019
Priority date	Mar 16, 2018
Publication date	Oct 17, 2023
Grant date	Oct 17, 2023

Abstract

This crane is provided with: a operable function unit; an operation unit; an actuator; a generation unit which generates a first control signal for the actuator on the basis of an operation input; a plurality of wire ropes; a plurality of hooks suspended from a leading end section of a boom by the plurality of wire ropes, respectively; a hook detection unit which detects, from among the plurality of hooks, an unused hook suspending no load; a calculation unit which calculates a resonance frequency for a wire rope, among the plurality of wire ropes, that suspends the detected unused hook; a filter unit which generates a filter on the basis of the resonance frequency and generates a second control signal by filtering the first control signal using the filter; and a control unit which controls the actuator on the basis of the second control signal.

First claim

The invention claimed is:

1. A crane comprising:
a operable function unit including at least a boom;
an operation unit that receives an operation input for operating the operable function unit;
an actuator that drives the operable function unit;
a generation unit that generates a first control signal of the actuator based on the operation input;
a plurality of wire ropes;
a plurality of hooks that is suspended from a leading end section of the boom by the plurality of wire ropes, respectively;
a hook detection unit that detects an unused hook which does not suspend a load among the plurality of hooks;
a calculation unit that calculates a resonance frequency for the wire rope suspending the detected unused hook among the plurality of wire ropes;
a filter unit that generates a filter based on the resonance frequency, and generates a second control signal by filtering the first control signal due to use of the filter; and
a control unit that controls the actuator based on the second control signal.

2. The crane according to claim 1 , further comprising:
a load detection unit that detects loads acting on the plurality of hooks,
wherein the hook detection unit detects the unused hook based on the detected loads.

3. The crane according to claim 2 ,
wherein the hook detection unit uses, as the unused hook, the hook whose detected load is the smallest among the plurality of hooks.

4. The crane according to claim 2 , further comprising:
a wire length calculation unit that calculates a length of a portion of each of the plurality of wire ropes which is suspended from the leading end section of the boom in a vertical direction,
wherein the hook detection unit uses, as the unused hook, the hook whose detected load is equal to or less than a load threshold value and is suspended by the wire rope of which the length in the vertical direction is the smallest among the plurality of hooks.

5. The crane according to claim 1 , further comprising:
a wire length calculation unit that calculates a length of a portion of each of the plurality of wire ropes which is suspended from the leading end section of the boom in the vertical direction,
wherein the hook detection unit detects the unused hook based on the calculated length in the vertical direction.

6. The crane according to claim 5 ,
wherein the hook detection unit uses, as the unused hook, the hook suspended by the wire rope of which the length in the vertical direction is the smallest among the plurality of wire ropes.

7. The crane according to claim 5 ,
wherein, when a difference between a length of a first wire rope, which is the wire rope whose length in the vertical direction is the longest, in the vertical direction and a length of a second wire rope, which is the wire rope whose length in the vertical direction is the smallest, in the vertical direction is equal to or greater than a length threshold value, the hook detection unit uses, as the unused hook, the hook suspended by the second wire rope.

8. The crane according to claim 1 ,
wherein the actuator includes at least one actuator of an expansion and contraction actuator for expanding and contracting the boom, a derricking actuator for derricking the boom, and a slewing actuator for slewing the boom.

9. The crane according to claim 1 ,
wherein the operable function unit includes a plurality of winches that is provided so as to correspond to the plurality of wire ropes, respectively, and lets out and pulls in the corresponding wire ropes, respectively, and
the actuator includes a plurality of winch actuators that is provided so as to correspond to the plurality of winches, respectively, and drives the corresponding winches, respectively.

10. The crane according to claim 1 ,
wherein the filter has a function of attenuating a frequency component of a predetermined frequency range using the resonance frequency as a reference at a predetermined ratio from the first control signal.

Assignees

• Tadano Ltd

Inventors

• Kanda Shinsuke
• Mizuki Kazuma

Classifications

• B66C13/30 Primary

  Circuits for braking, traversing, or slewing motors · CPC title

• B66C13/063 Primary

  electrical · CPC title

• B66C23/42

  with jibs of adjustable configuration, e.g. foldable · CPC title