GRATING

PROBLEM TO BE SOLVED: To enable the miniaturization and simplification of a hinge mechanism and smoothly and reliably perform a 180-degree opening/closing operation by improving the hinge mechanism of a 180-degree opening/closing type grating. SOLUTION: The grating is provided with a quadrangular receiving frame 1, a grating body 2 fitted into the receiving frame 1, and the hinge mechanism 14 for pivotally coupling one end part of the grating body 2 to the receiving part 1 in such a manner as to be freely rotated and opened/closed at an angle of 180 degrees. The hinge mechanism 14, coupled so as to be freely rotated about a pivot 20 on both sides of one end part of the grating body 2, is composed of a pair of joint plates 15 having a longitudinally long hole 17 oriented vertically in an eccentric place relative to a pivotal position and a pair of joint pins 22 and 24 fixed on both sides of the receiving frame 1 to be slidably inserted into the hole 17 and located on the upper-end side within the hole 17 in a closed condition. The receiving frame 1 is provided with a guide part 25 for moving and guiding the joint plate 15 vertically.