1. Field of the Invention
The present invention relates to an electric fan. More particularly, it relates to a structure for turning an air directing grille of an electric fan having an air directing grille in gyratory manner for varying the direction of air flow.
2. Description of the Prior Art
The conventional electric fan comprises a base for a fan, an electric motor placed on the upper part of the base and fan blades connected to a shaft of the motor. The direction of the air flow has been selected by facing the fan blades and the motor to desired directions by utilizing the rotation of the motor. Therefore, when the space is narrow, the range of movement of the fan blades and the motor has been limited to limit the direction of the air flow. It has been disadvantageously difficult to feed the air flow to desired directions.
It has been proposed to overcome such difficulty and to provide an electric fan for feeding air flow to broad region even though the equipping space is narrow, in Australian Pat. No. 459,701. In the example of the electric fan described in the specification of the patent, the electric fan comprises a casing having an air supply opening and an air suction opening and an electric motor and fan blades kept in the casing between the air supply opening and the air suction opening. A circular air directing grille having many slits for passing the air flow fed from the fan blades in linear or curved for a desired angle is placed in gyratory manner. The air directing grille is turned by connecting gear set for transmitting driving force of the motor. Moreover, a clutch is equipped for separating the power transmission between the air directing grille and the motor. In the structure for turning the air directing grille by directly connecting the gear set to the air directing grille as the Australian patent, when the turning of the air directing grille is forcibly stopped, excess force is applied to the motor. Thus, it is necessary to equip with a complicated clutch mechanism in the preparation of the electric fan. This is disadvantageous in view of the preparation of a thin compact electric fan.