| 摘要 |
PURPOSE:To obtain the captioned gear which is simple in structure and permanently usable without power being supplied by a structure wherein two semi- circular lid plates so constituted to be supported rotatably in opposite direction to each other about the axis normal to the chord of semi-circle respectively by means of a diaphragm and return springs are provided in a pent-roof plate and a wire-meshed perforated ventilating tube. CONSTITUTION:When indoor temperature rises the diaphragm 13 expands to push up a mobile plate 18 and a pusher 20. When the indoor temperature exceeds the fixed temperature, the pusher 20 contacts with and pushes up slant faces 10 and said pushing-up force excels the resultant force of the holding force of the edges of the slant faces 10 of the foots 9b of the mounting bodies 9 and of the reaction force of the return springs 12 to rotate the mounting bodies 9, resulting in opening the lid plates 11. Consequently, the ventilating tube (not shown) is cleared to allow the air pass therethrough. When the indoor temperature lowers and the diaphragm 13 contracts, the lid plates 11 are brought back to their original places by the force of the return springs 12, resulting in closing the ventilating tube. |
