GB2066362A - Improvements in or relating to electric fans - Google Patents

Abstract

An electric fan comprises a housing 1 in which is mounted an electric motor 2 and a fan blade assembly 3 driven by the electric motor. An air-directing grill 7 for directing the air flow from the fan blade assembly is connected to the motor via an oscillatory mechanism 8 which rotates the grill oscillatingly through an angle of less than 360 DEG . <IMAGE>

Description

SPECIFICATION Improvements in or relating to electric fans The present invention relates to electric fans, for instance of the floor or desk type.

According to the invention, there is provided an electric fan comprising a housing, an electric motor mounted in the housing, a fan blade assembly in the housing arranged to be driven by the motor, an air-directing grill for directing the flow of air from the fan blade assembly, and an oscillatory mechanism connecting the air-directing grill to the motor so as to cause the air-directing grill to rotate oscillatingly through an angle of less than 3600.

Preferably, the angle of rotary oscillation of the grill is substantially equal to 1800.

Preferably there is provided at least one inlet disposed between the fan blade assembly and the air-directing grill for augmenting the flow of air provided by the fan blade assembly.

The oscillatory mechanism may include a clutch for permitting the rotary oscillatory drive to the airdirecting grill to be disengaged.

Preferably the air-directing grill is readily detachably mounted on the oscillatory mechanism, for instance by a finger-operated screw, to permit easy detachment for cleaning purposes. Preferably a rear perforated fan guard and, where present, the or each inlet between the fan blade assembly and the flow-directing grill are readily detachably mounted to the housing, for instance by snap on/off means, to permit easy detachment for cleaning purposes.

The invention will be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a front view of an electric fan constituting a preferred embodiment of the invention: Figure 2 is a cross-sectional view on line A-A of Figure 1; Figure 2A shows in cross section a fan blade assembly of Figure 2 in a different position; Figure 3 is a front view of an air-directing grill of Figure 1; Figures 3A and 3B are cross-sectional views taken on lines B-B and C-C, respectively, of Figure 3; Figure 4 is a perspective view of the fan of Figure 1; and Figure 4A is an enlarged cross-sectional view of a detail of Figure 4.

The electric fan shown in the accompanying drawings comprises a housing 1 in which is provided an electric motor 2 and a fan blade assembly 3. The electric motor 2 is mounted in the housing 1 on supporting webs 4, which are formed integrally with or are rigidly connected to the housing 1. The rear of the housing 1 is closed by a perforated fan guard 5 which is detachably mounted to the housing 1. At the front of the housing 1 , there is provided a circular opening 6 in which is disposed a rotary air-directing grill 7.

The motor 2 has an output shaft which extends axially from either end of the motor. The fan blade assembly 3 is mounted on the rearwardly projecting part of the motor shaft and is disposed between the motor 2 and the perforated fan guard 5. The perforations in the fan guard 5 permit air to be drawn into the housing 5 by the fan blade assembly 3.

At the front of the motor 2, the output shaft portion extending therefrom is connected to an oscillatory mechanism 8, whose output is connected to a shaft 9 which is integral with a central hub 10 of the air-directinggrill 7.

The housing 1 is provided in each of its sides with a respective inlet in the form of a venturi grill 1 The venturi grills 11 are disposed generally between the fan blade assembly 3 and the airdirecting grill 7.

The rear perforated fan guard 5 is provided at its lower edge with integral extensions 12 which cooperate with holes formed in the bottom of the housing 1 to provide a lower detachable hinged connection between the fan guard 5 and the housing 1. At the top of the housing 1 , there are provided two integral extensions 13, which cooperate with holes 14 formed in the top edge of the fan guard 5 to provide for snap connection between the housing 1 and the fan guard 5. The rear perforated fan guard 5 may thus be readily removed from the housing for cleaning or washing by immersion in water. The venturi grills 11 may also be readily removed, for instance by sliding out of side apertures of the housing once the fan guard 5 has been removed, for immersion in water during washing.Finally, the air-directing grill is connected to the shaft 9 by means of a fingertighten screw 1 5 to permit ready detachment of the grill 7 for washing by immersion in water.

The top of the housing 1 is provided with a control box for the fan and a handle to permit the fan to be carried easily.

The air-directing grill 7 is shown in more detail in Figures 3, 3A and 3B. The grill has a first portion comprising a plurality of louvers 1 7 which extend at right angles to a louver 18, which forms a chord of the circular grill, to the nearer part of the circumference of the grill. The louvers 17 and 18 are disposed generally in planes parallel to the axis of the air-directing grill 7. Further louvers 19 extend transversely of the circular grill generally parallel to the louver 18, but in planes inclined to the axis of the grill. As shown in Figure 38, the further louver 1 9 nearest the louver 1 8 lies in a plane inclined at substantially 1 7 degrees to the axis of the air-directing grill 7.Moving upwardly in Figure 3B, the other further grills are disposed in planes at progressively increasing angles to the axis of the grill 7, the angles of adjacent further louvers 1 9 differing by 1 degree. Finally, the two further louvers 1 9 disposed furthest from the louver 18 are at the same angle of substantially 30 degrees to the axis of the grill 7.

In use, the fan blade assembly 3 is rotated by the electric motor 2 so as to draw air in through the perforations of the rear fan guard 5 in the direction of the arrows 20. Air from the fan blade assembly 3 travels generally axially of the housing 1, as indicated by the arrows 21 , towards the airdirecting grill 7 and passed the venturi grills 11.

This flow of air creates a low pressure area inside the housing, resulting in air being sucked in through the venturi grills 11 as indicated by the arrows 22, thus augmenting the flow of air provided by the fan.

The air-directing fan 7 directs the air flow out of the housing 1. In particular, the louvers 1 7 direct air generally axially of the grill as indicated by arrow 23. However, the further louvers 1 9 direct the air passing through this part of the grill 7 at an angle to the axis of the grill, as indicated by arrows 24.

The oscillatory mechanism 8 is driven by the motor 2 and causes the air-directing grill 7 to be rotated backwards and forwards between extreme angular positions spaced apart by 180 degrees.

Figures 1 and 2 show the air-directing grill at the clockwise most end of its oscillatory motion, whereas Figure 2A illustrate the grill at the anticlockwise most extreme of its motion. Figure 3 illustrates the position of the grill midway between the extremes of its oscillating rotary motion. Thus, the electric fan provides an air flow in a constant generally axial direction together with an air flow which is inclined to the axis of the grill 7 and swept over angle of 1 80 degrees such that this part of the air flow is never directed downwardly with respect to the housing 1. Accordingly, when the fan is placed on a surface, such as desk or floor, the air flow is never directed towards the surface and does not, for instance, stir up dust or loose fibres from a carpet. Thus, the health hazard created by inhalation of such dust or fibres is greatly reduced.

In order to clean the various inlets and outlets of the fan, these parts may be readily disassembled from the housing 1. Thus, the rear perforated fan guard 5 can be removed from the housing 1 by pressing down the extensions 13 such that they are free from the holes i 4. The fan guard 5 may then be hinged downwardly until the extensions 12 disengage from the holes in the bottom of the housing 1, thus freeing the fan guard 5 from the housing. The air-directing grill 7 can be removed by unscrewing the screw 15 by hand so as to release the grill 7 from the shaft 9.

The venturi grills 11 may also be readily detached from the housing. The fan guard 5, the grill 7, and the venturi grills 11 may then be cleaned by immersion in water, dired, and replaced on the housing 1 , the extensions 13 acting as snap-on fasteners in combination with the holes 14 formed in the fan guard 5.

The oscillatory mechanism 8 is provided with a clutch (not shown) to permit the air-directing grill 7 to be disengaged, when desired, from the oscillatory drive provided thereby.

Claims (10)

1. An electric fan comprising a housing, an electric motor mounted in the housing, a fan blade assembly in the housing arranged to be driven by the motor, an air-directing grill for directing the flow of air from the fan blade assembly, and ari oscillatory mechanism connecting the air-directing grill to the motor so as to cause the air-directing grill to rotate oscillatingly through an angle of less than 3600.

2. An electric fan as claimed in claim 1, in which the angle of rotary oscillation of the grill is substantially equal to 1 800.

3. An electric fan as claimed in claim 1 or 2, in which there is provided at least one inlet disposed between the fan blade assembly and the airdirecting grill for augmenting the flow of air provided by the fan blade assembly.

4. An electric fan as claimed in any one of the preceding claims, in which the oscillatory mechanism includes a clutch for permitting the rotary oscillatory drive to the air-directing grill to be disengaged.

5. An electric fan as claimed in any one of the preceding claims, in which the air-directing grill is readily detachably mounted on the oscillatory mechanism by a finger-operated screw.

6. An electric fan as claimed in any one of the preceding claims, in which a rear perforated fan guard and, where present, the or each inlet between the fan blade assembly and the airdirecting grill are readily detachably mounted to the housing.

7. An electric fan as claimed in any one of the preceding claims, in which the air-directing grill comprises a group of first louvres and a group of second louvres, the longitudinal axes of the first louvres extending perpendicularly to the longitudinal axes of the second louvres.

8. An electric fan as claimed in claim 7, in 'which the first louvres are disposed in planes parallel to the rotary axis of the air-directing grill and the second louvres are disposed in planes inclined to the rotary axis.

9. An electric fan as claimed in claim 8, in which the second louvre nearest the group of first louvres has the smallest inclination and the inclination of the second louvres increases progressively with distance from the group of first louvres.

10. An electric fan substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.