Abstract: A structure of a hinge is provided. The hinge includes a main leave secured to a door frame and a subordinate leave joint with the main leave by a pintle and secured to a door. The main leave has a first helical surface in a lower knuckle and the subordinate leave has a second helical surface in a central knuckle engaged with the first helical surface. Further the first helical surface has a vertical end and a plurality of domes engageable with a vertical end and a plurality of semi-circular recesses. So that when the door is opened, it will gradually and slowly closed on its own gravity.

Abstract: A structure of a hinge is provided. The hinge includes a main leave secured to a door frame and a subordinate leave joint with the main leave by a pintle and secured to a door. The main leave has a first helical surface in a lower knuckle and the subordinate leave has a second helical surface in a central knuckle engaged with the first helical surface. Further the first helical surface has a vertical end and a plurality of domes engageable with a vertical end and a plurality of semi-circular recesses. So that when the door is opened, it will gradually and slowly closed on its own gravity.

Abstract: A combination wrench with adjustable heads is provided. The wrench includes a handle and a open head and box head respectively pivoted to two ends of the handle. The open head is combined with a first and a second clamping jaws in shear arrangement. The box head is combined with a first and a second web pivoted together at their distal portions. When rotate the handle counterclockwise, both the open head and the box head can be able to firmly comp a wording object and then to fasten or unfasten the object. The handle can make back runs when it rotates clockwise.