Abstract: 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.

Abstract: An attachment coupler includes a first arm and a second arm, each including a U-shaped portion, and upper portions of the first and second arms being swingably connected by a swing shaft, and an expansion-contraction tool which opens and closes the first and second arms around the swing shaft as a fulcrum. A locking member provided with a cam and a hook provided with a cam follower are rotatably provided on the second arm. A state in which a free end of the hook is removed from an opening of the U-shaped portion is maintained by engagement of the cam and the cam follower during contraction of the expansion-contraction tool. The cam follower is driven by the cam along with rotation of the locking member during expansion of the expansion-contraction tool, thereby causing the free end of the hook to advance toward the opening of the U-shaped portion.

Abstract: A safety device for a device for fastening an attachment such as a bucket to the leading end of the arm of a power shovel is disclosed. Even if negligence and erroneous operation occur in combination, the attachment can be prevented from dropping from the arm end. To this end, mounting pins provided for the attachment are inserted into a pair of receiving recess portions which are arranged such that their openings face each other or their backs face each other and this inserted condition is maintained by hydraulic power. The fastening device includes: engagement metal fittings retractably attached in the vicinity of the receiving recess portions and having projections that are projectable into the openings of the recess portions; and lock members for engaging the engagement metal fittings, with their projections projecting into the openings.

Abstract: A slide arm for a work implement is provided, which is simply structured to obtain improved assembling precision thereby ensuring smooth operation. To this end, the slide arm is such that a plurality of tubular structural bodies (i.e., outer and inner tubes), each of which is formed by bending a one-piece plate into a shape having a substantially triangular cross-section and circular vertex portions, are telescoped one within the other with sliding members (i.e., plain bearing units and slide block pieces) interposed between them at the vertex portions and such that a sliding mechanism is disposed for sliding the tubular structural bodies.