Air supply channel or shaft lattice cover grid - has peripheral frame to support grid which engages with grid itself

摘要

The cover type lattice in partic. for use on air supply channels, shafts or similar items, has a peripheral frame and a lattice type grid or sieve device supported by means of the peripheral frame. It is constructed such that the frame has a lattice grid support grid which engages with the lattice grid. The grid itself has at least two flat sections set into it which have series of holes cut in them and which can be slid relative to each other. The grid bars may be orientated at an oblique angle relative to the frame.