Abstract:
A dry cell air pump that provides in excess of ten inches water column in pressure. A motor is used that draws fewer amps than prior art motors, yet operates at higher revolutions per minute. The small motor is capable of providing a high speed of rotation with relatively low torque, especially in comparison to prior art motors. To offset the low torque, a high efficiency fan is provided that rotates at high speeds, yet produces high air volume and pressure with reduced turbulence. The fan includes upper and lower walls enclosing the blades for the fan. The upper and lower walls minimize turbulence and maximize efficiency of the fan, providing a maximal tip velocity of the fan and thus increased pressure for the dry cell air pump. The fan includes a series of dimples along its upper surface that reduce back flow in the fan housing.

Description:
TECHNICAL FIELD OF THE INVENTION  
       [0001]     The present invention is directed to air pumps, and more specifically to air pumps for inflatable products.  
       BACKGROUND OF THE INVENTION  
       [0002]     An airbed is a large rectangular rubber or plastic bag that is filled with air so that it may be used as a bed. An airmat is similar in construction to an airbed, but is used as a float so that an individual may lie on the airmat on the water. Both products fall under the broad category of “inflatable” products. Other nonlimiting examples of inflatable products include rafts, inflatable furniture, inflatable pools, and inflatable boats.  
         [0003]     One thing inflatable products have in common is that they must be inflated for use. To this end, a valve or valves are supplied on each inflatable product for a user to provide air or another gas into the inflatable product. The user may utilize his or her breath, i.e., by blowing into a valve or valves, or may utilize a manual or electric pump. More often, for larger inflatable products, such as airbeds or inflatable boats, a pump is used.  
         [0004]     Electric pumps for inflatable products generally fall into three categories: alternating current (AC) pumps, which are supplied electricity through an electrical outlet; rechargeable pumps, which have rechargeable batteries that are recharged as needed; and pumps that utilize dry cell non-rechargeable direct current (“DC”) batteries (“dry cell air pumps”). The dry cell air pumps are popular, because they are relatively inexpensive and dry cell batteries are easy to obtain. One popular model utilizes four D-cell batteries. An example of such a model is shown in U.S. Design Pat. No. D445,804.  
         [0005]     Although the dry cell air pumps for the most part work well for their intended purpose, often they are limited in that they may not be able to supply a sufficient amount of pressure to adequately inflate larger inflatable products. For example, large airbeds, such as double-high airbeds, often require a large volume of air at high pressure to provide sufficient firmness for some individuals.  
         [0006]     Manufacturers have tried to address air pressure problems by providing as large of a motor as possible, given the voltage provided by the batteries. As an example, a four D battery dry cell air pump has six volts of dry cell power. One prior art four D dry cell air pump utilizes a six volt motor drawing 7.8 amps. In practice, it has been observed that 7.8 amps is too much of a draw on the motor, and the four D dry cell batteries can not maintain six volts and 7.8 amps, and more realistically produce four volts at approximately 3.5 amps. Thus, the results are that the motor runs too slowly, or that the batteries are stressed.  
         [0007]     The applicants are aware of prior art dry cell air pumps that have produced up to eight inches of water column (in WC) in pressure. Although eight in WC may produce firmness that is sufficient for some users of airbeds, there are users who desire a more firm airbed.  
       SUMMARY OF THE INVENTION  
       [0008]     The following presents a simplified summary of some embodiments of the invention in order to provide a basic understanding of the invention. This summary is not an extensive overview of the invention. It is not intended to identify key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some embodiments of the invention in a simplified form as a prelude to the more detailed description that is presented later.  
         [0009]     In accordance with an embodiment, a dry cell air pump is provided that provides in excess of ten inches water column in pressure. The dry cell air pump utilizes, in one embodiment, four D cell batteries.  
         [0010]     In accordance with an embodiment, a motor is used that utilizes less voltage than available from the batteries in the pump, allowing the motor to run at maximum efficiency. In one embodiment, a 4.0 volt motor is used with four D cell batteries. The small motor is capable of providing a high speed of rotation (e.g., 24,000 RPM&#39;s when loaded). However, the low voltage of the motor results in relatively low torque, especially in comparison to prior art motors. To offset the low torque, a high efficiency fan is provided that produces high air volume and pressure with little turbulence. The fan includes upper and lower walls enclosing the blades for the fan. The upper and lower walls minimize turbulence and maximize efficiency of the fan, providing a maximal tip velocity of the fan and thus increased pressure for the dry cell air pump, with very little torque requirement from the small electrical motor.  
         [0011]     In accordance with an embodiment, the fan includes a series of dimples along its upper surface. These dimples align with grooves in an upper part of the fan housing of the dry cell air pump. The engagement of the dimples with the grooves minimizes pressure loss and back air flow by interrupting air that attempts to flow backward along the top of the fan.  
         [0012]     Other features of the invention will become apparent from the following detailed description when taken in conjunction with the drawings, in which:  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]      FIG. 1  is a side perspective view of a dry cell air pump incorporating an embodiment of the invention;  
         [0014]      FIG. 2  is an exploded perspective view of the dry cell air pump of  FIG. 1 ;  
         [0015]      FIG. 3  is a cross sectional view taken along the section lines  3 - 3  of  FIG. 5 ;  
         [0016]      FIG. 4  is a side perspective view of a finger guard that may be used with the dry cell air pump of  FIG. 1  in accordance with an embodiment of the invention; and  
         [0017]      FIG. 5  is an exploded side perspective view of an upper portion of the fan housing of the fan for the dry cell air pump of  FIG. 1 .  
     
    
     DETAILED DESCRIPTION  
       [0018]     In the following description, various embodiments of the present invention will be described. For purposes of explanation, specific configurations and details are set forth in order to provide a thorough understanding of the embodiments. However, it will also be apparent to one skilled in the art that the present invention may be practiced without the specific details. Furthermore, well-known features may be omitted or simplified in order not to obscure the embodiment being described.  
         [0019]     Referring now to the drawings, in which like reference numerals represent like parts throughout the several views,  FIG. 1  shows a dry cell air pump  20  in accordance with an embodiment of the invention. Some aspects of the present invention may be utilized with electric pumps or manual pumps, but throughout this disclosure, the embodiments will be described with respect to a dry cell air pump, specifically the dry cell air pump  20 .  
         [0020]     The dry cell air pump  20  includes a motor housing  22  underneath a fan housing  24 , although the two housings may be arranged differently, or may be provided as a single structure. In the embodiment shown, four D cell batteries  26  are mounted within the motor housing  22  and about a motor  28 . A switch  30  is provided on the outside of the motor housing  22  for turning on and off operation of the dry cell air pump  20 . The D cell batteries  26  are removable from the motor housing  22  via a removable battery pan  32 . Latches  34  are provided for releasing and attaching the battery pan  32  to the bottom of the motor housing  22 . As such, the battery pan  32  may be removed to provide access to the inside of the motor housing  22  so that the D cell batteries  26  may be replaced. Contacts  36  are provided inside the motor housing  22  for providing power from the D cell batteries  26  to the motor  28  in accordance with operation of the switch  30  in a manner known in the art.  
         [0021]     In the embodiment shown, the fan housing  24  is formed by a fan cover  48  fitting over the motor housing  26 . The fan cover  48  is shaped so that, when it fits over the motor housing  26 , an internal air chamber  50  (shown generally in  FIG. 2 ) is formed. A fan  52  is mounted within the air chamber  50  for rotation by the motor  28 . An outlet  54  is positioned at one edge of the air chamber  50  for permitting flow of air out of the air chamber  50 , for example into an inflatable product via a flexible conduit (not shown, but known in the art). An inlet  55  is provided on the top of the fan housing  24  through which air is drawn into the fan  52 , which in turn is blown out through the outlets  54 .  
         [0022]     Details of the fan  52  can be seen in  FIG. 3 . The fan  52  includes a lower wall  56  and an upper cover  58 . The upper cover  58  serves as a wall that extends adjacent to the upper portion of the fan  52 . Blades  60  extend between the lower wall  56  and the cover  58  from a position spaced from a central access of the fan  52  outward to outer edges or tips of the fan  52 . An air inlet  62  is positioned centrally in the cover  58  and is in fluid communication with the blades  60 . In operation, the motor  28  rotates the fan  52  so that air is drawn through the inlet  55  in the fan housing  24  and down into the air inlet  62  of the fan. This air is then blown through the blades  60  and out of the tips of the fan  52 . The lower wall  56  and the upper cover  58  direct the majority of the air outward, in a more efficient manner than current designs.  
         [0023]     In accordance with an embodiment, the motor  28  utilizes less voltage than available from the batteries  26 , allowing the motor to run at maximum efficiency. In one embodiment, a 4.0 volt motor is used with four D cell batteries. For example, a Nichibo DC Motor, Model number LD3FN-5015B-C/58, produced by Nichibo Taiwan Corporation, Taipei, Taiwan, may be used, which has a maximum torque of 32.975 Amps and is capable of providing a high speed of rotation (24,200 RPM&#39;s with no load). However, the low voltage of the motor results in relatively low torque, especially in comparison to prior art motors. To offset the low torque, the high efficiency fan  52  is utilized that produces high air volume and pressure with less turbulence.  
         [0024]     Applicants have found that such a motor  28 , when operating with the fan  52 , can produce a significant amount of pressure out of the outlet  54  of the fan housing  24 . This pressure is provided in part because the motor  28  has sufficient power from the four D cell batteries  26  and in part because the fan  52  is a stable structure that is capable of rotating at high revolutions per minute, for example when loaded at approximately 14,000 revolutions per minute. By rotating the fan  52  at high speed, the tip velocity of the fan  52  is increased, thereby increasing the pressure of the air flowing out of the outlet  54  of the fan housing  24 . Applicants have found that utilizing the motor  28  described herein and a fan  52  having the following dimensions:  
                                                           Diameter   68.2   millimeters           Height   8.5   millimeters           Outer Slope of Upper Cover   7   degrees           Air Inlet Opening Diameter   24.818   millimeters           Total Wieght   0.024   pounds                      
 
 that a pressure of at least 10 inches of water can be provided and up to at least 12 inches of water. Utilizing such a structure, the dry cell air pump  20  is capable of inflating a double-high queen sized airbed in less than four minutes, with the airbed having significant firmness. Applicants are not aware of any prior art non-rechargeable dry cell air pump  20  that is capable of generating this type of air pressure, and particularly is not aware of four D cell battery models that are capable of producing this type of air pressure. 
 
         [0025]     In accordance with an embodiment, the cover  58  of the fan  52  includes dimples  64  positioned about the cover  58  of the fan  52 . The dimples  64  reduce pressure loss during rotation of the fan  52 , and reduce back air flow. As discussed above, in operation of the dry cell air pump  20 , air is blown out of the outlet  54 . As an inflatable product is filled, there is some air pressure push back from the inflatable product. The air that is push back-attempt to try to go over and under the fan. The air at the bottom of the fan  52  stabilizes, but the air at the top of the fan  52  attempts to go out the outlet  55  of the fan housing. It is believed that the dimples  64  partially block this travel of air to the outlet  55 , thus reducing back flow.  
         [0026]     In accordance with an embodiment, an aerodynamic finger guard  70  ( FIG. 4 ) is provided for the dry cell air pump  20 . The finger guard  70  may be used at the outlet  54 , the inlet  55 , or both. The finger guard  70  includes a structure for blocking a finger or a foreign object from entering the outlet  54  and/or the inlet  55 . In the embodiment shown, the structure is an “X”  72 , but other structures may be provided. In accordance with an embodiment, the structure blocking the user&#39;s finger or other foreign objects from entering the outlet  54  and/or the inlet  55  is shaped in an air foil design, minimizing turbulence for air flowing past the structure. As such, air flow volume and air pressure drop over the finger guard  70  is minimized.  
         [0027]     Other variations are within the spirit of the present invention. Thus, while the invention is susceptible to various modifications and alternative constructions, a certain illustrated embodiment thereof is shown in the drawings and has been described above in detail. It should be understood, however, that there is no intention to limit the invention to the specific form or forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention, as defined in the appended claims.  
         [0028]     All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.  
         [0029]     The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. The term “connected” is to be construed as partly or wholly contained within, attached to, or joined together, even if there is something intervening. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate embodiments of the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.  
         [0030]     Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.