Abstract: A robot hand for gripping workpieces to be forged which are subjected to impact loads is provided. The robot hand 2 includes a grip 3 for gripping a workpiece to be forged and a grip support 2a for supporting the grip 3. A grip guide 12 for supporting the grip 3 so that it is movable in a plane perpendicular to the longitudinal axis of the grip support and slidable in forward and rearward directions and a spherical seat 5 for bearing the grip guide 12 so that it can be inclined are provided within a casing 4 of the grip support 2a. The casing 3 of the grip support 2a is provided with various actuators 9, 10, 11, 7 for changing the supporting state between a state in which the grip 3 can be moved and inclined and a state in which the grip 3 can not be moved and inclined. The grip 3 is brought into the movable and inclinable state for absorbing an impact when the impact load is applied to the gripped workpiece to be forged.

Abstract: When an impact load is applied to a workpiece which is held by the robot, the impact force can be absorbed. The robot includes a grip 3 for holding a workpiece to which an impact load is applied and a buffer mechanism disposed between the grip 3 and a robot arm 2. The buffer mechanism 4 includes two parallel link mechanisms 5, 6 for enabling the grip 3 to be moved in various directions and hydraulic actuator mechanisms 7, 8 for relaxing the actuation of the parallel link mechanisms 5, 6. When an impact force is applied to the grip 3, two parallel link mechanisms 5, 6 are actuated so that the grip 3 is slightly displaced while the hydraulic actuator mechanisms 5, 6 relax the actuation of the parallel link mechanisms 7, 8. Therefore, the impact force which is applied to the grip 3 can be absorbed. Additionally, after the impact force is applied to the grip 3, the buffer mechanism 4 can immediately be returned automatically to the initial position.

Abstract: A denitration catalyst comprising at least three metal components, (A) titanium, (B) tungsten and/or magnesium, and (C) vanadium, the titanium and tungsten being contained as oxides and the magnesium and vanadium being contained in the form of an oxide or a sulfate or both, said catalyst being composed of a porous molded article of a mixture of an oxide of component A and an oxide and/or a sulfate of component B, the atomic ratio of component B to component A being from 0.01 to 1, and a vanadium compound localized in that area of said molded article which extends from its outermost surface to a depth of 500 microns or less, the content of the vanadium compound in said area being 0.1 to 15% by weight; and a method for removing nitrogen oxides from a waste gas, which comprises contacting a waste gas containing nitrogen oxides, together with ammonia and molecular oxygen, at a temperature of 150.degree. to 650.degree. C., with the aforesaid catalyst.