1. Field of the Invention
The present invention relates to a ventilator for cleaning the air inside the rooms of buildings.
2. Prior Art
Presently, there are many different types of ventilators for circulating the air between the inside and the outside of the rooms of a building. One type of the ventilators uses a plurality of pivoting slats. These slats are arranged in cross formation and installed in vertical and horizontal directions in a square frame. Both ends of each slat are attached to the opposite or facing side edges of the square frame in a pivotal fashion.
In this type of conventional ventilator, both ends of each slat are kept in contact perpendicularly with the inner wall surfaces of the side edges of the square frame. Accordingly, projecting pieces are used for mounting the slats. The projecting pieces are provided so as to project perpendicularly from the inside wall surfaces of the frame, and holes formed at both ends of the slat are fitted over these projecting pieces so that the slats can pivot.
However, if the frame is round in shape and not a square, it is difficult to install a plurality of slats in a pivotal fashion and in a cross formation inside the round frame.