GB2240588A - Ventilating fan - Google Patents

Abstract

A ventilating fan includes a casing (1) enclosing an electric motor (2) having a rotational shaft, a fan blade (4) driven by the motor (2). The fan blade (4) includes a hub portion (5) coupled to the rotational shaft of the motor (2) and a blade portion (6) detachably attached to the hub portion (5). The blade portion (6) which is likely to be soiled is formed from any one of a foaming material, sheet material and paper so as to be replaceable by a new one. Alternatively, the front frame (22) includes a base portion (23) attached to the casing (1) and a detachable portion (24) having a bell mouth (22a) and detachably attached to the base portion (23). The detachable portion (24) is formed from any one of the foaming material, sheet material and paper so as to be replaceable with a new one. <IMAGE>

Description

VENTILATING FAN This invention relates to ventilating fans wherein either or both of blades of a fan blade and a bellmouth surrounding the fan blade and its peripheral portion which are likely to be soiled during a ventilating operation and are conspicuous are replaceable by respective new ones.

Ventilating fans are generally used for exhausting filthy air in a room or lamp smoke or soot induced in a kitchen. Since lamp dust or the like contained in the soot adheres to a fan blade and front decorative frame of the ventilating fan, the fan blade and front frame are gradually rendered dirty and the ventilating fan appearance is defiled. For preventing the fan blade and front frame from becoming dirty, they need to be periodically cleaned.

However, the lamp dust adherent to the surfaces of fan blade and front frame cannot be completely wiped away with a dustcloth or the like and accordingly, the fan blade and front frame are usually detached from the frame of the ventilating fan and washed in water. It is thus troublesome to wash the fan blade and front frame in water at every time of the cleaning.

For improvement of the above-described troublesome cleaning, a strippable paint has recently been applied to the surfaces of the fan blade and front frame such that paint films are formed thereon. In this case, the paint films are stripped away every time the fan blade and the front frame become dirty. Furthermore, a filter is attached to the front of the ventilating fan so that the lamp dust or the like is collected by the same.

However, in the case of forming strippable paint films, it takes much time for a user to apply a paint to the surfaces of the fan blade and front frame to thereby form uniform paint films thereon. Furthermore, the paint film thickness is likely to be ununiform and torn when stripped away. Thus, the paint film applying work is troublesome.

In the case of attaching a filter to the front side of the ventilating fan, it would be impossible to completely collect the lamp dust with the filter. Consequently, adherence of the lamp dust or the like to the fan blade and the front frame is unavoidable even when the filter is attached to the front of the ventilating fan. Thus, the cleaning efficiency cannot be completely improved by attachment of the filter to the front of the ventilating fan.

Therefore, an object of the present invention is to provide a ventilating fan wherein the cleaning efficiency may be improved.

The present invention provides a ventilating fan comprising a casing enclosing an electric motor having a rotational shaft and a fan blade driven by the motor, the fan blade including a hub portion coupled to the rotational shaft of the motor and a blade portion detachably attached to the hub portion, the blade portion being formed from any one of a foaming material, a sheet material and paper.

Since the blade portion of the fan blade which is most likely to be soiled are formed from a low-cost material such as a foaming material, sheet material or paper, it may be thrown away and replaced by a new one at a low cost.

Accordingly, what a user has to do at the time of the cleaning is to detach the soiled blade portion from the hub portion and replace it by the new one. Since the soiled blade portion is replaced by the new one, the soil adherent to the blade portion may be completely removed therefrom and the appearance of the ventilating fan may be prevented from being defiled.

The invention may be practiced by a ventilating fan comprising a casing enclosing an electric motor, a fan blade driven by the motor, and a front frame attached to the front side of the casing, the front frame including a base portion attached to the casing and a detachable portion detachably attached to the base portion and having a bellmouth surrounding the fan blade, the detachable portion of the front frame being formed from any one of a foaming material, a sheet material and paper.

Since the peripheral portion of the bellmouth or the detachable portion of the front frame which is most likely to be soiled is formed from any one of the foaming material, sheet material and paper, the detachable portion of the front frame may be thrown away and replaced by a new one at a low cost. Consequently, in the cleaning of the ventilating fan, what the user has to do is to replace the soiled detachable portion of the front frame by a new one.

As in the case of the foaming material, the sheet material may be obtained at low cost and accordingly, the detachable portion may be provided as a throwaway part.

The invention will be described, merely by way of example, with reference to the accompanying drawings, in which: FIG. 1 is a longitudinal cross sectional view of a ventilating fan of an embodiment of the present invention; FIG. 2 is an exploded perspective view of a motor and a fan blade of the ventilating fan of the embodiment; and FIG. 3 is an exploded perspective view of a front frame of the ventilating fan of the embodiment.

The ventilating fan of an embodiment of the present invention will now be described with reference to the accompanying drawings. Referring first to FIG. 1, a casing 1 of the ventilating fan is mounted on a wall (not shown) of the kitchen, for example. The casing 1 encloses an electric motor mounted on a mounting frame 3. The motor 2 has a rotational shaft 2a forwardly extended. A fan blade 4 includes includes a hub or base portion 5 at which the fan blade is coupled to the rotational shaft 2a of the motor 2 and a blade portion 6 (see FIG. 2) detachably attached to the hub portion 5. The hub portion 5 has a central throughhole 7 into which the rotational shaft 2a is inserted and a rear end engagement groove 8 which is engaged with a securing pin 9 fixed through the rotational shaft 2a, for detent.In this condition, a nut 10 is threadably engaged with an end threaded portion 2b of the shaft 2a, thereby fixedly mounting the hub portion 5 on the rotational shaft 2a. The hub portion 5 has, in the front side, a counterbore 11 for the nut tightening purpose, a pair of positioning projections 12 and a pair of elongated engagement holes 13.

The blade portion 6 comprises a central cup-shaped portion 6a and a plurality of blade members 6b formed integrally with the cup-shaped portion so that the elements are circumferentially radially extended therefrom. The central cup-shaped portion 6a has a pair of positioning holes 14 into which the positioning projections 12 are inserted for the positioning of the blade portion 6 and a pair of elongated through-holes 15 corresponding to the engagement holes 13. A spinner 16 employed for detachably attaching the blade portion 6 to the hub portion 5 has a pair of generally L-shaped engagement strips 17 extended rearwardly thereof. The engagement strips 17 of the spinner 16 are inserted through the holes 15 of the cup-shaped portion 6a and then into the engagement holes 13, respectively.

Subsequently, the spinner 16 is turned in the clockwise direction such that the end portions of the L-shaped engagement strips 17 are engaged with the edge portions of the engagement holes 13, respectively, thereby fixinq the blade portion 6 to the hub portion 5.

The casing 1 has a rear opening which is closed by three shutter members 18 mounted thereon for rotative movement. The upper ends of the shutter members 18 are coupled to a generally L-shaped lever 19 which can be lifted and lowered. A switch box 20 is disposed at the lower side of the casing 1. When a'switch string 21 hung down on the switch box 20 is manually drawn, the L-shaped lever 19 is lowered, thereby opening the shutter members 18.

Simultaneously, the motor 2 is energized to thereby drive the fan blade 4.

A front frame 22 is detachably attached to the front side of the casing 1. The front frame 22 comprises a base portion 23 (see FIG. 3) attached to the front side of the casing 1 and a detachable portion 24 (see FIG. 3) having a bellmouth 24a surrounding the fan blade 4. The base portion 23 comprises a generally rectangular frame member 23a and a flat plate portion 23b having a circular opening 25 and formed integrally with the frame member 23a at the inside thereof. The flat plate portion 23b has four corner portions where attaching holes 26 are formed, respectively.

The frame member 23a of the base portion 23 has an engagement projection 27 (see FIG. 1) formed on the rear end inner periphery thereof. The base portion 23 is detachably attached to the casing 1 by engaging the engagement projection 27 with an elastic engagement strip 28 (see FIG. 1) formed on a front end flange la of the casing 1. On the other hand, the detachable portion 24 of the front frame 22 comprises a decorative panel portion 24b and a central bellmouth 24a formed integrally with the portion 24b. The decorative panel portion 24b has four projections 29 formed on four corner portions of the backside thereof, respectively. The detachable portion 24 is detachably attached to the flat plate portion 23b of the base portion 23 by force fitting the projections 29 into holes 26, respectively.In the condition that the detachable portion 24 is attached to the flat plate portion 23b, the front side or flat plate portion 23b of the base portion 23 is covered by the decorative panel portion 24b of the detachable portion 24 and the bottom of the base portion 23 is covered by a cover portion 24c formed so as to be bent rearwardly from the lower edge of the decorative panel portion 24b. A lamp reservoir 30 is formed in the lower most portion of the bellmouth 24a.

As described above, the fan blade 4 is divided into the hub portion 5 and blade portion 6 which are formed from materials different from each other. The front frame 22 is also divided into the base portion 23 and the detachable portion 24 having the bellmouth 24a and the base portion 23 and the detachable portion 24 are formed from materials different from each other. In the embodiment, the hub portion 5 and base portion 23 are formed from a material providing the strength enough to withstand the long period use, such as polypropylene plastics.The blade portion 6 and detachable portion 24 are formed in one of the following three methods for the purpose of lowering the production costs thereof and being replaceable: 1) The blade portion 6 and the detachable portion 24 are formed by foaming a foaming material such as a foam polystyrene or from a foaming material sheet by way of the vacuum forming. These foam products need less amount of material than the prior plastics products formed by way of the injection molding. Consequently, the material costs and therefore, the production costs of these parts may be lowered to a large extent.

2) The blade portion 6 and the detachable portion 24 are formed from a sheet material such as a polypropylene sheet by way of the vacuum forming, blow molding, hot press forming or the like. The forming process in each of these methods is simplified as compared with the prior injection molding, which reduces the forming cost. Furthermore, the thickness of the sheet material is reduced and consequently, the material cost is also reduced. Thus, the production cost may be reduced to a large extent.

3) The blade portion 6 and the detachable portion 24 are formed from paper by way of pressing. The paper may be obtained at low cost and the pressing does not require high forming cost. As a result, the production cost may be reduced to a large extent.

In operation of the above-described ventilating fan, the fan blade 4 and front frame 22 are gradually soiled with reiterative ventilating operations. In the ventilating operation, the indoor air is sucked toward the bellmouth 24a and exhausted along the outer periphery of the hub portion 5 of the fan blade 4. Consequently, the bellmouth 24a and its peripheral portion (the decorative panel portion 24b) and the blade portion 6 which are positioned along the flow of exhausted air are concentrically soiled. The other portions of the ventilating fan such as the upper wall and right-hand and left-hand side walls of the front frame 22 or spinner 16 are not so spoiled and not conspicuous.Since the blade portion 6 and the detachable portion 24 (bellmouth 24a and decorative panel portion 24b) are dividable from the hub portion 5 and the base portion 23, respectively, the soiled blade portion 6 and the detachable portion 24 are replaced by the respective new ones when the soil thereon becomes remarkable.

In replacement of the throwaway blade portion 6, the spinner 16 is first turned in the counterclockwise direction and both of the L-shaped engagement strips 17 are drawn out of the holes 13, respectively, thereby detaching the spinner 16. As a result, the blade portion 6 is detached from the hub portion 5. Subsequently, the new blade portion 6 is put on the hub portion 6 and the through-holes 15 are caused to correspond to the engagement holes 13. Then, the L-shaped engagement strips 17 of the spinner 16 are inserted through the through holes and into the holes 13, respectively. The spinner 16 is then turned in the clockwise direction. The distal ends of the L-shaped engagement strips 17 are engaged with the edge portions of engagement holes 13, thereby securing the blade portion 6 to the hub 5.

On the other hand, in the replacement of the throwaway detachable portion 24, the soiled detachable portion 24 is drawn forwardly such that the projections 29 are pulled out of the holes 26, respectively, thereby detaching the detachable portion 24 from the base portion 23.

Subsequently, the new detachable portion 24 is put on the base portion 23 and the projections 29 are inserted into holes 26, respectively, thereby securing the same to the base portion 23.

The soiled blade portion 6 and detachable portion 24 detached are dumped away. Such a replacement is rendered possible for the reasons that these parts are formed from the foaming material, sheet material or paper which reduces the production costs thereof and that not overall fan blade 4 and front frame 22 but the blade portion 6 and detachable portion 24 as parts of them are replaced. Accordingly, in the ventilating fan of the embodiment, the fan blade 4 and front frame 22 need not be washed in water every time the ventilating fan is to be cleaned. Further, such a troublesome work as applying the strippable paint to the fan blade 4 and front frame 22 is not needed and the ventilating fan is free from the problems of occurrence of ununiform thickness of the paint and tear of the paint in the case where the paint is stripped. Thus, the cleaning of the ventilating fan may be done with ease by replacing the soiled fan blade 4 and front frame 22 with respective new ones.

Furthermore, since the blade portion 6 and the detachable portion 24 which are conspicuous are replaced by the respective new ones every time the ventilating fan is cleaned, the appearance of the ventilating fan may be maintained at that of the new one and the soil adherent to the portion of the ventilating fan seen at the room interior may be completely removed away.

Furthermore, since the blade portion 6 and the detachable portion 24 are formed from the foaming material, sheet material or paper all of which are relatively low in durability, the blade portion 4 and detachable portion 24 may be broken into pieces with ease when they are dumped away. Thus, the blade portion 6 and detachable portion 24 are not bulky and may be collected as wasted articles with ease.

It is more or less inevitable that the durability of each of the blade portion 6 and detachable portion 24 is lowered as compared with those of the prior art. However, since these parts may be replaced by new ones in the ventilating fan of the present invention, the durability of each of these parts is not required to be so high that they are durable for a sufficient long period as in the prior art ventilating fans. Accordingly, the durability of each of the blade portion 6 and detachable portion 24 is only required to be at such a level that they are durable for a relatively short period from the start of use to the time they become dirty. Such a level of durability may be sufficiently obtained from the foaming material, sheet material or paper. Moreover, the blade portion 6 and detachable portion 24 formed from these materials weigh light.Should these parts fall off during operation of the ventilating fan, that would not cause any injury to persons.

Additionally, since employment of the light-weight blade portion 6 improves unbalance thereof, the vibration and therefore, noise generated during the ventilating operation may be reduced.

Since the replaceable blade portion 6 and detachable portion 24 of the fan blade 4 and front frame 22 may be reinforced by the non-replaceable hub portion 5 and base portion 23, respectively, the durability of the ventilating fan may be improved.

Furthermore, since the hub portion 5 is interposed between the rotational shaft 2a of the motor 2 and the blade portion 6, the heat transfer from the motor 2 to the blade portion 6 may be restrained by the hub portion 6, thereby preventing deformation of the blade portion 6 due to heat.

Although both of the blade portion 6 of the fan blade 4 and the detachable portion 24 of the front frame 22 are throwaway parts in the foregoing embodiment, any one of them may be a throwaway part. Furthermore, films may be applied to the surfaces of the blade portion 6 and detachable portion 24 for the purpose of reinforcement.

The foregoing disclosure and drawings are merely illustrative of the principles of the present invention and are not to be interpreted in a limiting sense. The only limitation is to be determined from the scope of the appended claims.

Claims (3)

WHAT WE CLAIM IS:

1. A ventilating fan comprising a casing enclosing an electric motor having a rotational shaft and a fan blade driven by said motor, said fan blade including a hub portion coupled to the rotational shaft of said motor and a blade portion detachably attached to said hub portion, said blade portion being formed from any one of a foaming material, a sheet material and paper.

2. A ventilating fan comprising a casing enclosing an electric motor, a fan blade driven by said motor, and a front frame attached to the front side of said casing, said front frame including a base portion attached to said casing and a detachable portion detachably attached to said base portion and having a bellmouth surrounding said fan blade, said detachable portion of said front frame being formed from any one of a foaming material, a sheet material and paper.

3. A ventilating fan substantially as herein described with reference to the accompanying drawings.