Pumps – Motor driven – Electric or magnetic motor
Reexamination Certificate
2000-05-03
2002-04-02
Freay, Charles G. (Department: 3746)
Pumps
Motor driven
Electric or magnetic motor
Reexamination Certificate
active
06364637
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an air pump apparatus for sucking and/or discharging air. Particularly, the present invention pertains to an air pump apparatus that is suitable for use in a vacuum suction type pick-up tool used in a clean room to pick up a semiconductor wafer or the like.
BACKGROUND OF THE INVENTION
Air pump apparatuses are conventionally used in picking up an object such as a semiconductor wafer by using vacuum suction or in scattering materials by using discharge function of the air pump apparatus. Such air pump apparatuses can be also used in aeration of water in an aquarium for keeping goldfish or other aquatic animals or plants. Thus, air pump apparatuses are used in a variety of fields.
Such an air pump apparatus is disclosed for example in U.S. Pat. No. 4,170,439, Japanese Utility Model Application Laid-Open (Kokai) No. 63-46704 or Japanese Utility Model Registration No. 2565626. The air pump apparatus disclosed in No. 2565626 comprises a plurality of diaphragms disposed in a pump chamber and the diaphragms are driven by an electromagnetic drive means utilizing an electromagnet and permanent magnet to conduct air inlet (suction) and air outlet (discharge) operations.
The diaphragm-type air pump apparatuses including those disclosed in the above publications have several advantages over the air pump apparatuses of other types: for example, the diaphragm-type air pump apparatuses can operate without oil and thus can avoid contaminating the surroundings; they tend to produce low noise and oscillation; and the constituent parts thereof have an extended lifetime, reducing the burdens in maintaining the diaphragm-type air pump apparatuses. Therefore, the diaphragm-type air pump apparatuses are suitable for such a use that requires functional steadiness of the pump for an extended period of time and in that contamination of the surroundings should be avoided, e.g., for use as a discharge pump for aeration of water in an aquarium or for use as a suction pump to pick-up a semiconductor wafer using vacuum suction.
In the prior art, however, when it became necessary to increase the pump capacity (or performance) beyond an adjustable range of a single pump apparatus (for example when the aquarium was replaced by a significantly larger one or when it became necessary to pick up a wafer having a significantly larger size and weight), either the entire pump apparatus had to be replaced by a new pump apparatus having a sufficiently high pump capacity or one or more additional pump apparatuses having a similar pump capacity had to be connected to the existing pump apparatus in series by using external piping.
In the former case, the user need to purchase an expensive high-capacity pump apparatus and has to find a new usage for the replaced pump apparatus or wastefully discard it while in the latter case, the external piping and additional power supply and control devices are necessary besides the additional pump main bodies, and they would not only make the total apparatus size considerably larger but also render the operation of the apparatus complicated. Also, the connection of the separate pump apparatuses using the external piping would be quite cumbersome and not readily achieved. Thus, in both cases, the user has to bear undesirable expenses and other burdens. On the part of pump apparatus manufacturers also, there was a problem that they had to provide various types of air pump apparatuses having different pump capacities, and this hindered simplification of the product management and cost reduction of the products.
BRIEF SUMMARY OF THE INVENTION
In view of such problems of the prior art and the recognition by the inventors, a primary object of the present invention is to provide an air pump apparatus that allows easy change of the number of pump mechanisms contained therein and easy connection between the pump mechanisms.
A second object of the present invention is to provide an air pump apparatus that allows addition of a pump mechanisms without considerable increase in the pump apparatus size.
A third object of the present invention is to provide an air pump apparatus that allows an easy electrical connection from the power source to the pump mechanisms contained in the pump apparatus as well as easy operation of the pump mechanisms.
A fourth object of the present invention is to provide a diaphragm-type pump mechanism adapted so as to be easily added to or removed from an air pump apparatus.
According to the present invention, these and other objects can be accomplished by providing an air pump apparatus, comprising: a first pump mechanism; and a pump case assembly forming a first air-tight pump chamber in that the first pump mechanism is contained, wherein the first pump mechanism comprises: a base frame having a first end and a second end opposite to the first end, the first and second ends of the base frame defining an axial direction of the air pump apparatus; mutually opposing first and second diaphragms defining first and second diaphragm chambers on lateral sides of the base frame respectively; electromagnetic drive means for driving the first and second diaphragms so as to expand and contract the first and second diaphragm chambers; a first inlet port defined in the first end of the base frame for communicating air into the first diaphragm chamber upon expansion of the first diaphragm chamber, with a first one-way valve being provided between the first inlet port and the first diaphragm chamber for permitting air flow only into the first diaphragm chamber; a second inlet port defined in the base frame for communicating air into the second diaphragm chamber upon expansion of the second diaphragm chamber, a second one-way valve being provided between the second inlet port and the second diaphragm chamber for permitting air flow only into the second diaphragm chamber; a first outlet port defined in the base frame for discharging air from the first diaphragm chamber upon contraction of the first diaphragm chamber, a third one-way valve being provided between the first outlet port and the first diaphragm chamber for permitting air flow only out of the first diaphragm chamber; and a second outlet port defined in the second end of the base frame for discharging air from the second diaphragm chamber upon contraction of the second diaphragm chamber, a fourth one-way valve being provided between the second outlet port and the second diaphragm chamber for permitting air flow only out of the second diaphragm chamber, and the second outlet port being in axial alignment with the first inlet port, and wherein the first inlet port and the second outlet port of the first pump mechanism are in flow communication with outside of the first pump chamber, and the first outlet port and the second inlet port of the first pump mechanism are in flow communication with the first pump chamber.
In the air pump apparatus constructed as above, since the pump mechanism is implemented as an independent unit, addition of a pump mechanism can be readily carried out. The pump case assembly defining the air-tight pump chamber for containing the pump mechanism therein to make a pump unit comprising two series-connected diaphragm chambers can be easily modified in accordance with addition or removal of a pump mechanism. Since the diaphragm chambers are defined on lateral sides of the base frame of the pump mechanism, the pump mechanism has a relatively small axial size and thus achieving an air pump apparatus having a reduced axial length. This feature will be particularly preferable when achieving a multi-unit air pump apparatus comprising a plurality of series connected pump mechanisms. Further, since the first inlet port and the second outlet port of the first pump mechanism is in axial alignment, an additional pump mechanism having an identical configuration to the first pump mechanism can be quite easily aligned with and connected to the first pump mechanism without using an external pipe or the like, to thereby simplify the connection and achieve a compact air pump
Hase Masahiro
Takahashi Kazuo
Takahashi Kiyoshi
Freay Charles G.
Marshall & Melhorn LLC
Rodriguez William H
Takahashi Kiyoshi
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