Background Art As well known to those skilled in the art, aquariums are glass-sided tanks, bowls, or the like, in which fish or other living aquatic animals are kept. In order to keep fish or other living aquatic animals within an aquarium for a lengthy period of time, it is necessary to continuously supply feed and oxygen to fish or other living aquatic animals. Particularly, the amount of oxygen laden in water of an aquarium is limited, and so fresh air laden with plentiful oxygen must be continuously supplied into the water of the aquarium using an air pump.

Figs. 1 and 2 show the construction and operation of a conventional air pump for aquariums. As shown in the drawings, the conventional air pump for aquariums comprises a pumping unit set within an external casing. The pumping unit of the conventional air pump comprises two stators 1 installed within a housing 5, with one vibrator 2 installed between the two stators 1 and two diaphragms 3 assembled with opposite ends of the vibrator 2. When the conventional air pump is turned on, an AC voltage is applied to the two stators 1, and so the vibrator 2 linearly vibrates to the left and right at the position between

the two stators 1. When the vibrator 2 performs such a linear vibration as described above, the diaphragms 3 also linearly vibrate to pump air in two pumping chambers 4 of the housing 5 so as to supply air laden with plentiful oxygen to a desired position, that is, an aquarium, through an air feed pipe (not shown).

In such a conventional air pump, the vibrator 2 along with the two diaphragms 3 continuously, repeatedly and linearly vibrates to the left and right at least several hundred times per minute for a lengthy period of time. The vibrator 3 in addition to the stators 1, each consisting of a coil wound around a core, is thus undesirably overheated. Therefore, it is necessary to repeatedly stop the operation of the air pump at predetermined intervals so as to cool the heated stators 1 and vibrator 3. The conventional air pump for aquariums is thus inconvenient to users. When the overheated stators 1 and vibrator 3 of the conventional air pump are left for a period of time without being properly cooled, the stators 1 and vibrator 3 may be severely damaged or broken to reduce the expected life span of the air pump and force a user to purchase a new air pump.

The two diaphragms 3 are assembled with opposite ends of the vibrator 2 as shown in Figs. 1 and 2, and pump air in the pumping chambers 4 in cooperation with two sub-diaphragms 3a set in each pumping chamber 4. Each of the two diaphragms 3 has a disc shape with an annular flange entirely formed along the outside edge, thus forming flat opposite surfaces 6 and 7, and so each diaphragm 3 may be not uniformly fatigued or stressed, but may be undesirably, concentratively fatigued and stressed at a specific portion when they repeatedly perform an air pumping operation by the quick linear vibrating motions. The diaphragms 3 are thus partially damaged, cracked or broken at the concentratively stressed portions.

When such cracks, caused by the concentrative fatigue and stress, are accumulated on each diaphragm 3, the air pumping force of the diaphragms 3 is reduced to shorten the expected life span of the air pump.

Disclosure of the Invention

Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide an air pump for aquariums, which automatically and effectively cools the coils of two stators and the core of a vibrator with air without using any separate cooling means during an operation, and which effectively absorbs and disperses fatigue and stress applied to the diaphragms during an operation, thus lengthening the expected life span of the diaphragms in addition to those of the stators and vibrator.

In order to accomplish the above object, the present invention provides an air pump for aquariums, having two stators and a vibrator within a housing assembled with a side cover and having an air guide channel at its lower portion and used for pumping atmospheric air so as to supply the air into water of an aquarium, comprising: a diaphragm assembled with at least one end of the vibrator and used for pumping the air in a pumping chamber of the housing in accordance with a linear vibrating motion of the vibrator; and an air guide panel mounted to at least one of the top, bottom and sidewalls of the housing and provided with an air inlet at the edge thereof, thus guiding atmospheric air into the housing.

In the air pump, the diaphragm has an annular flange entirely formed along the outside edge, thus having a depressed first surface and a flat second surface, the diaphragm also having an annular groove having predetermined radius, depth and width, and concentrically formed on the depressed first surface of the diaphragm, and an annular dam having the same radius as that of the annular groove and a predetermined height, and formed on the second surface of the diaphragm at a position corresponding to the annular groove.

The air guide panel further comprises a noise attenuation wall having a specifically bent linear profile, and arranged on the air guide panel to form an air channel communicating with the air inlet, and two air guide openings formed on the air guide panel so as to guide air from the air channel of the air guide panel into the housing.

The air pump further comprises an air guide pipe extending upward from the air guide panel to a predetermined height, thus guiding air from the air channel

of the air guide panel into a predetermined position within the housing.

The air guide panel is assembled with a top cover at its open side, thus forming the air channel communicating with the air inlet.

Brief Description of the Drawings The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: Fig. 1 is an exploded perspective view of the pumping unit of a conventional air pump for aquariums; Fig. 2 is a sectional view, showing the operation of the conventional air pump for aquariums; Fig. 3 is an exploded perspective view, showing the construction of a pumping unit of an air pump for aquariums in accordance with the primary embodiment of the present invention; Fig. 4 is an exploded perspective view, showing the construction of the air pump of the present invention, with the pumping unit of Fig. 3 set within an external casing of the air pump; Fig. 5 is a sectional view, showing the operation of the air pump according to the primary embodiment of this invention; Fig. 6 is a partially broken perspective view of a diaphragm included in the air pump for aquariums of the present invention; Fig. 7 is a perspective view, showing the construction of an air guide panel included in the air pump for aquariums of the present invention; and Fig. 8 is an exploded perspective view of a pumping unit of an air pump for aquariums in accordance with another embodiment of the present invention.

Best Mode for Carrying Out the Invention Reference now should be made to the drawings, in which the same

reference numerals are used throughout the different drawings to designate the same or similar components.

Figs. 3 to 8 are views, showing the construction and operation of air pumps for aquariums in accordance with the preferred embodiments of present invention.

The construction and operation of the air pump for aquariums in accordance with the primary embodiment of this invention will be described herein below with reference to Figs. 3 to 7. As shown in the drawings, the pumping unit of the air pump for aquariums according to the primary embodiment comprises two stators 102 installed within a housing 101, with a vibrator 103 set between the two stators 102. Two diaphragms 104 are assembled with opposite ends of the vibrator 103, and are positioned such that the edge of each diaphragm 104 is fixed to the peripheral edge of an associated pumping chamber 105. When the air pump is turned on, an AC voltage is applied to the two stators 102, and so the vibrator 103 linearly vibrates to the left and right at the position between the two stators 102. When the vibrator 103 linearly vibrates as described above, the diaphragms 104 compress air within the two pumping chambers 105 in cooperation with sub-diaphragms 104a set in the pumping chambers 105, and feed the compressed air laden with oxygen into water of an aquarium.

The lower end of the housing 101 of the pumping unit is assembled with a damper 106 having a hollow structure, with an air guide panel 107 interposed between the lower end of the housing 101 and the damper 106. The air guide panel 107 has a specifically designed air guide channel, with two air inlets 108 provided at opposite sides of the panel 106. The air guide panel 107 thus guides atmospheric air into the housing 101.

As best seen in Fig. 7, a first noise attenuation wall 109, having a specifically bent linear profile, is arranged on the lower surface of the air guide panel 107, and forms an air guide channel in cooperation with the upper surface of the damper 106 when the air guide panel 107 is closely positioned on said upper surface of the damper 106. Two air guide pipes 110 extend upward from the air guide panel 107 to a predetermined height, thus guiding air from the air guide

channel of the panel 107 into the housing 101. In such a case, it is desired to make the two air guide pipes 110 directly guide air to the core of the vibrator 103 so as to cool said core with the air. Two air guide openings 112 are formed on the air guide panel 107 so as to guide air from the air guide channel of the panel 107 into the housing 101. In such a case, it is desired to make the openings 112 directly guide air from the air guide channel of the panel 107 to the coils of the stators 102 so as to cool said coils with the air.

Of course, it should be understood that the structure of the air guide channel, formed by the first noise attenuation wall 109 of the air guide panel 107 on the damper 106, may be somewhat freely changed in accordance with the positions and shapes of the air guide pipes 110, air guide openings 112, air inlets 108, stators 102 and vibrator 103 without affecting the functioning of this invention.

In addition, the two pumping chambers 105, each having two sub- diaphragms 104a, are formed at opposite open sides of the housing 101 by assembling two side covers 113 to said opposite open sides of the housing 101.

An air guide tube 114 extends from the pumping chamber 105 of each side cover 113 downward to the interior of the damper 106, thus guiding air from the pumping chamber 105 into the damper 106.

The damper 106 is assembled with the lower end of the housing 102 using a plurality of locking members 115. When the pumping unit is set within an external casing 119 of the air pump, the lower ends of the locking members 115 are inserted into the locking bosses 118 interiorly formed on a lower casing 116 of the external casing 119 such that the damper 106 is suspended above the lower casing 116. In the present invention, the locking members 115 are made of a flexible material capable of effectively absorbing and attenuating the operational vibrations when the housing 101 vibrates due to the linear vibrating motion of the vibrator 103 and diaphragms 104 during an operation of the air pump. The air pump of this invention is thus somewhat free from operational vibrations or noises.

An upper casing 117 is assembled with the lower casing 116 to form the external casing 119 of the air pump for setting the pumping unit therein. An air guide

depression 120, having a predetermined depth, is formed on the top wall of the upper casing 117 as shown in Fig. 4, with a plurality of air inlet holes 111 formed at the bottom wall of the air guide depression 120 to introduce atmospheric air into the external casing 119 during an operation of the air pump as shown in Fig. 5.

Two air inlet channels linearly extend from diametrically opposite positions on the edge of the air guide depression 120 to the edge of the top wall of the upper casing 117, thus allowing atmospheric air to be sucked into the air guide depression 120 during an operation of the air pump.

A specifically designed second noise attenuation wall 121, having an arc- shaped profile, is arranged on the bottom surface of the air guide depression 120 as best seen in Fig. 4. This second noise attenuation wall 121 has a predetermined height and a predetermined radius of curvature. A top cover 122 covers the top of the air guide depression 120 such that the interior of the air guide depression 120 communicates with the atmosphere only through the two air inlet channels.

Each of the two diaphragms 104 has a disc shape with a predetermined diameter, and pumps air within an associated pumping chamber 105 in cooperation with two sub-diaphragms 104a set in the pumping chamber 105. An annular flange is entirely formed along the outside edge of each diaphragm 104, and so the first and second surfaces 123 and 125 of the diaphragm 104 become a depressed surface and a flat surface as shown in Fig. 6. An annular groove 124, having a predetermined dimension, is concentrically formed on each diaphragm 104 at the depressed first surface 123. Due to the formation of the annular groove 124 on the depressed first surface 123, an annular dam 126 is formed on the second surface 125 of the diaphragm 104 at a position corresponding to the groove 124.

The above-mentioned air pump of this invention is operated as follows: When the air pump is turned on, an AC voltage is applied to the two stators 102, and so the vibrator 103 linearly vibrates to the left and right at the position between the two stators 102. When the vibrator 103 linearly vibrates as described above, the diaphragms 104 assembled with opposite ends of the vibrator 103 also linearly vibrate to pump air within the pumping chambers 105 of the two side covers 113 in cooperation with the sub-diaphragms 104a set in the pumping

chambers 105 as shown in Fig. 5. In such a case, the positional directions of the two sub-diaphragms 104a in each pumping chamber 105 are opposite to each other, and so one of the two sub-diaphragms 104a is opened, while the other is closed in response to an air compressing or air sucking movement of an associated main diaphragm 104. Therefore, it is possible for the main and sub-diaphragms 104 and 104a to pump air in one direction without allowing a reverse flow of air, thus supplying compressed air from the pumping chambers 105 into the damper 106 through the air guide tubes 114. The air is, thereafter, supplied from the damper 106 to a desired position, that is, an aquarium, through an air feed pipe (not shown) extending from an air discharging port 127 of the damper 106 to the aquarium.

When air is pumped from the pumping chambers 105 in response to a linear vibration of the vibrator 103, the amount of air within the housing 101 is reduced, and so fresh air is newly supplied from the interior of the external casing 119 into the housing 101. In such a case, the air from the interior of the casing 119 is guided into the housing 101 through the air guide channel of the air guide panel 107 positioned at the lower end of the housing 101. That is, the air from the interior of the casing 119 is primarily introduced into the air guide channel of the panel 107 through the two air inlets 108, and flows through the air guide channel under the guide of the first noise attenuation wall 109. In such a case, the first noise attenuation wall 109 smoothly guides the air current while effectively attenuating any noises caused by the flow of air current within the channel.

Part of air is discharged from the air guide channel of the panel 107 through the two air guide pipes 110 of the panel 107 to reach the core of the vibrator 103, thus cooling said core. On the other hand, the air is also partially discharged from the air guide channel of the panel 107 through the two air guide openings 112 of the panel 107 to reach the coils of the two stators 102, thus cooling said coils.

The air pump of this invention thus automatically and effectively cools the coils of the two stators 102 and the core of the vibrator 103 without using any separate cooling means during an operation.

Fig. 8 is an exploded perspective view of a pumping unit of an air pump for aquariums in accordance with the second embodiment of the present invention.

In this second embodiment, the air guide panel 107 is installed at a top opening formed at the top of the housing 101, different from the primary embodiment with the air guide panel 107 provided at the lower end of the housing 101. In an operation of the air pump of this second embodiment, fresh air is guided from the interior of the external casing 119 into the housing 101 through the air guide channel of the air guide panel 107 in the same manner as that described for the primary embodiment, but the air is introduced into the housing 101 from the top of the housing 101 in place of the bottom.

In the second embodiment, a top cover 129 covers the top opening of the housing 101, with the air guide panel 107 set in the housing 101 such that the noise attenuation wall 109 of the panel 107 forms a desired air guide channel in cooperation with the lower surface of the top cover 129.

On the other hand, atmospheric air is continuously sucked into the interior of the external casing 119 since the air within the casing 119 is continuously supplied into the housing 101 during an operation of the air pump. In such a case, the introduction of atmospheric air into the interior of the external casing 119 is accomplished by the air inlet holes 111 formed at the bottom wall of the air guide depression 120 of the upper casing 117 as shown in Fig. 4.

The air guide depression 120 is formed on the top wall of the upper casing 117 to have a predetermined depth, with the two air inlet channels linearly extending from diametrically opposite positions on the edge of the air guide depression 120 to the edge of the top wall of the upper casing 117. In addition, the top cover 122 covers the top of the air guide depression 120 such that the interior of the air guide depression 120 communicates with the atmosphere only through the two air inlet channels. The second noise attenuation wall 121, having an arc-shaped shape with a predetermined height and a predetermined radius of curvature, is arranged on the bottom surface of the air guide depression 120.

Therefore, atmospheric air is primarily guided to the air guide depression 120 through the two air inlet channels, and secondarily flows in the depression 120

under the guide of the second noise attenuation wall 121 prior to being sucked into the external casing 119 through the air inlet holes 111. In such a case, the second noise attenuation wall 121 smoothly guides the air current while effectively attenuating any noises caused by the flow of air current within the air guide depression 120.

It is thus possible for the air pump of this invention to attenuate the operational noises caused by air flowing into the interior of the external casing 119 through the air guide depression 120.

When the pumping unit is set within the external casing 119 of the air pump, the lower ends of the locking members 115, used for assembling the damper 106 with the lower end of the housing 102, are inserted into and held by the locking bosses 118 projecting from the interior surface of the lower casing 116 to a height. Therefore, the damper 106 is not closely positioned on the interior surface of the lower casing 106, but is suspended above the lower casing 116 at a height determined by the projecting bosses 118. The operational vibrations of the damper 106 are thus not transmitted to the lower casing 116, but are almost completely intercepted by the locking members 115, and so it is possible to attenuate the operational vibrations and noises of the damper 106.

In the present invention, the locking members 115 are preferably made of a flexible material. The locking members 115 thus prevent the operational vibrations of the damper 106 from being transmitted to the lower casing 116 since they more effectively absorb and attenuate the vibrations when the housing 101 and the damper 106 vibrate due to the linear vibrating motion of the vibrator 103 during an operation of the air pump. On the other hand, in order to hold the top cover 122 on the top opening of the air guide depression 120, it is preferable to use a lid 128, which is mounted to the upper casing 117 using a plurality of set screws (not shown) such that the lid 128 allows the top cover 122 to be opened at a side.

The vibrator 103 is set between the two stators 102 within the housing 101. The two diaphragms 104, assembled with the opposite ends of the vibrator 103, are positioned such that the edge of each diaphragm 104 is fixed to the peripheral edge of an associated pumping chamber 105 so as to pump air in the

pumping chamber 105. In an operation of the air pump, the two diaphragms 104 continuously, repeatedly and linearly vibrate to the left and right at least several hundred times per minute while being concentratively fatigued and stressed at a specific portion as shown in Fig. 6. The diaphragms 104 may be thus partially damaged, cracked or broken at the concentratively stressed portions.

However, in the present invention, an annular groove 124 is concentrically formed on each of the diaphragms 104 at the depressed first surface 123, and so the diaphragms 104 are smoothly deformed at the annular grooves 124 while absorbing stress applied thereto during a repeated and linear vibration. The stress, absorbed by the annular groove 124 of each diaphragm 104, is uniformly dispersed to the entire area of the diaphragm 104 from the annular dam 126 of the second surface 125. Therefore, it is possible to attenuate impact applied to the diaphragms 104, and effectively prevent a formation of partial cracks on the diaphragms 104 even though the diaphragms 104 continuously, repeatedly and linearly vibrate to the left and right several hundred times per minute for a lengthy period of time.

In a brief description, since each of the diaphragms 104 has the annular groove 124 on the first surface and the annular dam 126 on the second surface 125, each diaphragm 104 effectively absorbs stress at the annular groove 124 and uniformly disperses the absorbed stress to the entire area of the diaphragm 104 from the annular dam 126. The diaphragms 104 are thus uniformly fatigued and stressed, and can be usable for a desired lengthy period of time.

Industrial Applicability As described above, the present invention provides an air pump for aquariums. In the air pump of this invention, the coils of the stators and the core of the vibrator are automatically cooled by air without requiring any separate cooling means. This air pump also has first and second noise attenuation walls capable of smoothly guiding inlet air currents into the external casing and the housing, thus effectively attenuating operational noises caused by the inlet air

currents. Therefore, this air pump allows a user to use the pump under a quite environment, thus being convenient to the user. In addition, an annular groove and an annular dam are formed on each diaphragm, which continuously and repeatedly vibrates at least several hundred times per minute and may be concentratively fatigued and stressed at a specific portion. In an operation of the air pump, each diaphragm absorbs stress at the annular groove, and uniformly disperses the absorbed stress to its entire area from the annular dam. The diaphragms are thus prevented from being exceedingly deformed or stressed during an operation of the air pump, and so the diaphragms perform an active pumping operation for a desired lengthy period of time. The air pump of this invention thus accomplishes highly improved pumping efficiency and lengthens its expected life span.

Although a preferred embodiment of the present invention has been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.