Working machine attachment attaching and detaching device

A working machine attachment attaching and detaching, device including a first member and a second member, said first member having a basic end adapted to be connected to a forward end of a working machine arm with a first cross-pin, said first member being rotatable around said first cross-pin by extension and contraction of a hydraulic cylinder, said second member having a basic end connected to a forward end of said first member with a second cross-pin, a working machine attachment includes a third cross-pin and a fourth cross-pin, said first member is adapted to engage said third cross-pin near the first member basic end, and said second member is adapted to engage said fourth cross-pin at a forward end of said second member, said working machine attachment attaching and detaching device comprising:

• a stop pin,
• a pair of side plates provided as said second member disposed opposite to each other in a transverse direction and having an integral configuration,
• wherein each of said side plates has a first horizontal through-hole for inserting said stop pin, and a recessed portion provided with front and rear slant faces forming an opening space which widens more toward a forward end,
• a fifth cross-pin located between said side plates, and
• a hook which is connected near its center with said fifth cross-pin,
• wherein said hook has a bend at a connecting portion with said fifth cross-pin, dividing it into an upper portion and a lower portion and forming it into an L-shape, said upper portion being a spindle portion having a second horizontal through-hole for inserting said stop pin, said lower portion being a hook body which opens to said recessed portions, said L-shape being formed such that a lower face of said spindle portion partly protrudes from bottoms of said recessed portions, and said hook body opens to said recessed portions to fully open the recessed portions when said hook is balanced rotationally around said fifth cross-pin by its own weight, and
• wherein said first and second members and said first and second horizontal through-holes are configured such that said fourth cross-pin is located beneath both said recessed portions when said third cross-pin is engaged to the basic end of said first member,
• said machine attachment device further comprising;
• said fourth cross-pin adapted to abut either of said front or rear slant faces and slide up the same after the engagement of said third cross-pin, and when said hydraulic cylinder is extended, said fourth cross-pin approaches a bottom of said recessed portions while also abutting the lower face of said spindle portion causing the rotation of said hook around said fifth cross-pin, this rotation yielding said hook body to enclose said fourth cross-pin from lower sides of said recessed portions, said enclosing enabling said stop pin to be inserted into said first and second horizontal through-holes, this insertion fixing said hook to said second member, thereby engaging said fourth cross-pin at the forward end of said second member.