Patent attributes
An attachment coupler is attached to an end of an arm of a working machine. An attachment having two attachment pins in parallel can be detachably attached to the attachment coupler. The attachment coupler includes a first U-shaped portion that engages with and supports one of the attachment pins sideways, and a second U-shaped portion that receives the other attachment pin downwardly. The second U-shaped portion includes a rotary hook that opens and closes the opening of the second U-shaped portion. The rotary hook includes an engagement securing member that engages with and secures the rotary hook when the rotary hook closes the opening of the second U-shaped portion and when the rotary hook opens the opening of the second U-shaped portion, and a bolt securing member that secures the rotary hook with a bolt when the rotary hook closes the opening of the second U-shaped portion.