Abstract:
An air pumping/extracting duplex pump for use in an inflatable device for selectively pumping air into/out of an air chamber of an inflatable device is constructed to include two connected housing, and an actuating mechanism mounted in the housings and manually rotatable between a first position for drawing air into the inflatable device and a second position for drawing air out of the inflatable device.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an air pump and, more specifically, to an air pumping/extracting duplex pump adapted for use in an inflatable device to selectively inflate/deflate the inflatable device. 
     2. Description of the Related Art 
     When inflatable/deflating a big inflatable device, an air pump is used. A big inflatable device generally has a first one-way air valve for enabling air to pass to the inside, and a second one-way air valve for enabling air to pass to the outside. When inflating this kind of big inflatable device with an air pump, the air exhaust port of the air pump is connected to the first one-way air valve of the inflatable device. On the contrary, when deflating this kind of big inflatable device with an air pump, the air suction port of the air pump is connected to the second one-way air valve of the inflatable device. This inflatable device inflating or deflating procedure is complicated. 
     SUMMARY OF THE INVENTION 
     The present invention has been accomplished under the circumstances in view. It is one object of the present invention to provide a duplex pump, which is practical for use in an inflatable device to selectively inflate/deflate the inflatable device. It is another object of the present invention to provide an air pumping/extracting duplex pump, which is easy to operate. To achieve these and other objects of the present invention, the air pumping/extracting duplex pump is installed in an inflatable device having a flexible shell defining an air chamber, and adapted for selectively pumping air into/out of the air chamber of the inflatable device. The air pumping/extracting duplex pump is comprised of a first housing, a second housing, and an actuating mechanism. The first housing is fixedly fastened to the flexible shell of the inflatable device, comprising an air chamber, an air inlet and an air outlet respectively disposed in communication between the air chamber of the first housing and the air chamber of the inflatable device, a first one-way air valve installed in the air outlet for enabling air to pass from the air chamber of the first housing into the air chamber of the inflatable device, and a second one-way air valve installed in the air inlet for enabling air to pass from the air chamber of the inflatable device into the air chamber of the first housing. The second housing is fixedly fastened to the first housing and extended to the outside of the inflatable device, comprising an air chamber disposed in communication with the air chamber of the first housing, a first opening disposed in communication with the air chamber of the second housing and the atmosphere, a second opening disposed in communication with the air chamber of the second housing and the air chamber of the first housing, and an annular airflow control plate fixedly fastened to the periphery of the second opening, the annular airflow control plate having a radially inwardly protruded first stop flange and at least one radially inwardly protruded second stop flange. The actuating mechanism is mounted in the first housing and the second housing and rotatable relative to the first housing and the second housing between a first position for drawing air into the air chamber of the inflatable bed and a second position for drawing air out of the air chamber of the inflatable device. The actuating mechanism comprises an outward flange supported on the airflow control plate, a first part disposed at one side of the outward flange inside the air chamber of the first housing, and a second part disposed at an opposite side of the outward flange inside the air chamber of the second housing, the first part having an air suction hole, an air exhaust hole, and a protruded portion, the outward flange having a first air hole disposed in communication with the exhaust hole and at least one second air hole disposed in communication between the first part and the second part. When the actuating mechanism rotated to the first position, the first stop flange of the airflow control plate blocks the first air hole of the actuating mechanism, the at least one second air hole of the actuating mechanism each is opened, and the air exhaust hole of the actuating mechanism is in communication with the air outlet of the first housing for enabling outside air to be drawn into the air chamber of the inflatable device upon operation of the actuating device. When the actuating mechanism rotated to the second position, the protruded portion of the actuating mechanism opens the second one-way air valve, the air exhaust hole of the actuating mechanism is moved away from the air outlet of the first housing and blocked by the periphery of the first housing, the first air hole of the actuating mechanism is moved away from the first stop flange of the airflow control plate and opened, and the at least one second air hole is respectively blocked by the at least one stop flange of the airflow control plate, enabling air to pass from the air chamber of the inflatable device through the air inlet of the first housing, the air chamber of the first housing, the first air hole of the actuating mechanism, the air chamber of the second housing, and the first opening of the second housing to the outside of the inflatable device. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded view of an air pumping/extracting duplex pump according to the present invention. 
     FIG. 2 is an applied view of the present invention, showing the air pumping/extracting duplex pump installed in an air bed. 
     FIG. 3 is a schematic drawing showing the relative positioning between the airflow control plate and the outward flange of the motor holder of the actuating mechanism during inflating mode. 
     FIG. 4 is a schematic drawing showing the relative positioning between the actuating mechanism and the first housing during inflating mode. 
     FIG. 5 is a schematic drawing showing the relative positioning between the airflow control plate and the outward flange of the motor holder of the actuating mechanism during deflecting mode. 
     FIG. 6 is a schematic drawing showing the relative positioning between the actuating mechanism and the first housing during deflecting mode. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIGS. 1 and 2, an air pumping/extracting duplex pump in accordance with the present invention is generally comprised of a first housing  1 , a second housing  2 , and an actuating mechanism  3 . The air pumping/extracting duplex pump can be used in, for example, an inflatable air bed  4 . The inflatable air bed  4  comprises a collapsible plastic shell  41  defining an air chamber  40 . The air pumping/extracting duplex pump is adapted to inflate/deflect the air bed  4 . 
     The first housing  1  is fixedly fastened to the collapsible plastic shell  41  of the air bed  4  by a heat sealing apparatus and suspended inside the air chamber  40 , having an air chamber  10 , an air inlet  12  and an air outlet  11  respectively disposed in communication between the air chamber  10  of the first housing  1  and the air chamber  40  of the air bed  4 , a first one-way air valve  13  installed in the air outlet  12  for enabling air to pass from the air chamber  10  of the first housing  1  into the air chamber  40  of the air bed  4 , and a second one-way air valve  14  installed in the air inlet  12  for enabling air to pass from the air chamber  40  of the air bed  4  into the air chamber  10  of the first housing  1 . The first one-way air valve  13  is comprised of a fixed casing  131  fixedly fastened to the air outlet  11  of the first housing  1 , a movable valve rod  132  inserted through the fixed casing  131 , a stopper  133  fixedly fastened to one end of the movable valve rod  132  and adapted for stopping the air passage through the air outlet  11 , and a spring  134  connected between the casing  131  and the stopper  133  and adapted for supporting the stopper  133  in the close position to close the air passage through the air outlet  1 . The structure of the second one-way air valve  14  is similar to the first one-way air valve  13  with the exception of its reversed installation direction. 
     The second housing  2  is fastened to the first housing  1  and extended to the outside of the inflatable air bed  4 , having an air chamber  20  disposed in communication with the air chamber  10  of the first housing  1 , a first opening  21  disposed in communication with the air chamber  20  and the atmosphere, a second opening  22  disposed in communication with the air chamber  20  of the second housing  2  and the air chamber  10  of the first housing  1 , and an annular airflow control plate  23  fixedly fastened to the periphery of the second opening  22  by a heat sealing apparatus and O-ring  220 . The annular airflow control plate  23  has one first stop flange  231  and at least one, for example, three second stop flanges  232 . The stop flanges  231 ; 232  are radially inwardly protruded from the inner diameter of the annular airflow control plate  23  into the air chamber  20 . 
     The actuating mechanism  3  according to the present preferred embodiment is a centrifugal fan comprising a rotary base  31 , a fan motor  32 , a motor holder  33  fixedly fastened to the rotary base  31  and holding the fan motor  32  on the inside, a fan blade  34  disposed outside the motor holder  33  and coupled to the fan motor  32 , and a cover  35  fixedly fastened to the motor holder  33  and covered over the fan blade  34 . The cover  35  has a center air suction hole  36 , a radial exhaust hole  37 , and a protruded portion  39 . The motor holder  33  has an outward flange  38  supported on the annular airflow control plate  23 . The outward flange  38  divides the whole actuating mechanism  3  into a first part  301  suspended in the air chamber  10  of the first housing  1  and a second part  302  suspended in the air chamber  20  of the second housing  2 . Therefore, the center air suction hole  36  and radial exhaust hole  37  of the cover  35  are disposed is in the air chamber  10  of the first housing  1 . Further, the outward flange  38  of the motor holder  33  has a first air hole  381  disposed in communication with the radial exhaust hole  37  of the cover  35 , and a plurality of second air holes  382  disposed in communication between the first part  301  and the second part  302 . 
     When installed in the inflatable air bed  4  as shown in FIG. 2, the rotary base  31  is extended out of the first opening  21  of the second housing  2  for operation by the user, and the actuating mechanism  3  is disposed inside the first housing  1  and the second housing  2  on the middle and rotatable relative to the first housing  1  and the second housing  2  between a first position and a second position. 
     Referring to FIGS. 3 and 4 and FIG. 1 again, when the actuating mechanism  3  manually rotated to the first position, the first stop flange  231  of the annular airflow control plate  23  blocks the first air hole  381  of the motor holder  33 , leaving the second air holes  382  opened, and the radial exhaust hole  37  of the cover  35  is abutted against the air outlet  1  of the first housing  1 . At this time, outside air passes through the first opening  21  of the second housing  2  into the air chamber  20  of the second housing  2 , and then passes through the second air holes  382  of the motor holder  33  into the air chamber  10  of the first housing  1 , and then passes from the air chamber  10  of the first housing  1  through the center air suction hole  36  and then the radial exhaust hole  37  to rush open the first one-way air valve  13  and then to pass to the inside of the air chamber  40  of the inflatable air bed  4 , and therefore the inflatable air bed  4  is inflated. 
     Referring to FIGS. 5 and 6 and FIG. 1 again, when the actuating mechanism  3  manually rotated to the second position, the protruded portion  39  is forced into the air inlet  11  of the first housing  1  to open the second one-way air valve  13 ; the radial exhaust hole  37  is moved away from the air outlet  11  of the first housing  1  and blocked by the peripheral wall of the first housing  1   m  the first air hole  381  is moved away from the first stop flange  231  of the airflow control plate  23  and opened; and the second air holes  382  are respectively blocked by the second stop flanges  232  of the airflow control plate  23 . At this time, air passes from the air chamber  40  of the inflatable air bed  4  through the air inlet  12  of the first housing  1  into the air chamber  10  of the first housing  1 , and then passes from the air chamber  10  of the first housing  1  through the center air suction hole  36  of the cover  35  to the air chamber  20  of the second housing  2  via the first air hole  381  of the motor holder  33 , and then passes from the air chamber  20  of the second housing  2  to the outside through the first opening  21  of the second housing  2 , and therefore the inflatable air bed  4  is deflated. 
     Referring to FIG. 1 again, a cap  24  is connected to the second housing  2  with O-ring  240  by a link  25 , and adapted for closing the first opening  21  of the second housing  2  to protect the actuating mechanism  3 . 
     A prototype of air pumping/extracting duplex pump has been constructed with the features of FIGS. 1-6. The air pumping/extracting duplex pump functions smoothly to provide all of the features discussed earlier. 
     Although a particular embodiment of the invention has been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.