Patent ID: 7734376

Claim:
A hand as an end effector, comprising: a base; a hook element associated with said base, and capable of hooking and lifting an object; a holding element associated with said base, and cooperating with said hook element to hold said object therebetween; and a drive section causing a relative linear movement between said hook element and said holding element; wherein said hook element includes an end adapted to hook an object thereon, and allows the object to be automatically displaced into a balanced orientation, due to gravity, with a center of gravity of the object being located substantially vertically beneath said hook element, when said hook element hooks on and lifts the object without an operation of said drive section; and wherein said hook element and said holding element are adapted to be relatively shifted in a direction toward each other by an operation of said drive section, and hold the object between said end of said hook element and said holding element under a pressure exerted by said drive section.