Crane

Patent metadata

Field	Value
Publication number	US-10836612-B1
Application number	US-201816954125-A
Country	US
Kind code	B1
Filing date	Dec 18, 2018
Priority date	Dec 18, 2017
Publication date	Nov 17, 2020
Grant date	Nov 17, 2020

Abstract

The present invention is provided with: a manipulation unit; a winch device that operates with an actuation mode of either a high speed mode or a low speed mode, and winds in or reels out a wire rope; a selection unit for an operator to select either the high speed mode or the low speed mode; a load calculation unit calculating a suspended load; a tension calculation unit calculating the tension of the wire rope; and a control unit controlling the actuation of the winch device. If the mode selected by the selection unit is the high speed mode, the manipulation unit is manipulated from a neutral state to a non-neutral state, and the suspended load is smaller than a load threshold and the tension is smaller than a tension threshold, the control unit controls the winch device so as to operate in the high speed mode.

First claim

The invention claimed is:

1. A crane comprising:
a manipulation unit;
a winch device that operates with an actuation mode of either a high speed mode or a low speed mode based on manipulation of the manipulation unit, and winds in or reels out a wire rope to which a hook is fixed;
a selection unit for an operator to select either the high speed mode or the low speed mode;
a load calculation unit for calculating a suspended load;
a tension calculation unit for calculating a tension of the wire rope; and
a control unit for controlling actuation of the winch device,
wherein the winch device comprises a high/low speed hydraulic motor capable of switching between a first mode corresponding to the high speed mode and a second mode corresponding to the low speed mode,
if determining that a mode selected by the selection unit is the high speed mode, the manipulation unit is in a state of being manipulated to a hoisting side or in a state of being manipulated on a lowering side as a non-neutral state from a neutral state, the suspended load is smaller than a load threshold, and the tension is smaller than a tension threshold, the control unit switches the high/low speed hydraulic motor to the first mode to operate the winch device in the high speed mode, starts to wind in the wire rope using the winch device when the manipulation unit is manipulated to the hoisting side, and starts to reel out the wire rope using the winch device when the manipulation unit is manipulated to the lowering side.

2. The crane according to claim 1 , wherein
the high/low speed hydraulic motor includes a high/low speed switching valve and a control cylinder,
the high/low speed switching valve is capable of switching between a first state where hydraulic oil is supplied from the high/low speed switching valve to the control cylinder and a second state where supply of the hydraulic oil from the high/low speed switching valve to the control cylinder is interrupted, under control of the control unit, and
the high/low speed hydraulic motor has a motor displacement on a large displacement side corresponding to the low speed mode in the second state, and has the motor displacement on a small displacement side corresponding to the high speed mode in the first state.

3. The crane according to claim 1 , wherein
the control unit performs switching control to switch the actuation mode from the high speed mode to the low speed mode if a state where the suspended load is equal to or larger than the suspended load threshold continues for a predetermined time or if a state where the tension is equal to or larger than the tension threshold continues for a predetermined time in a state where the winch device operates in the high speed mode.

4. The crane according to claim 3 , wherein
after the switching control, the control unit maintains the actuation mode in the low speed mode until the manipulation lever becomes neutral.

5. The crane according to claim 1 , wherein
the control unit controls the winch device to operate in the low speed mode if the low speed mode is selected by the selection unit in a state where the actuation mode is the high speed mode.

Assignees

• Tadano Ltd

Inventors

• Masuda Naotaka
• Urushihara Kenji
• Kawano Takashi

Classifications

• B66C13/44 Primary

  Electrical transmitters · CPC title

• B66D1/505

  electrical · CPC title

• B66C13/20 Primary

  for non-electric drives (transmitting control pulses B66C13/40) · CPC title

• B66C23/54

  with pneumatic or hydraulic motors, e.g. for actuating jib-cranes on tractors · CPC title

• B66C23/88

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