Abstract:
An air mattress inflator/deflator assembly includes a cylindrical housing which contains a device for pressurizing the housing, generally a blower and motor. The blower is located near one end of the housing, and pressurizes its interior. One or more valves are selectively operable to direct the pressurized air in the housing to tubing which communicates with an air mattress. The internal pressure of the air mattress can be increased by activating the motor and blower and a valve, pressurizing the housing and directing pressurized air to the air mattress. The internal pressure of the air mattress can be decreased by activating a valve, and releasing air in the air mattress through the housing and out to the ambient. A closed cell foam block surrounds the housing and an intake muffler both reduce operating noise levels.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates generally to an assembly for inflating and deflating air mattresses and more specifically to an air mattress inflator/deflator assembly which provides controlled inflation and deflation of an associated air mattress and generates minimal noise during operation. 
     Mattresses have evolved through the years much as many other consumer products. Decades ago a standard mattress comprised metal springs with layers of padding over the springs. 
     From about 1970 to 1980, interest in water filled mattresses peaked. While they are still popular, many consumers consider their relatively great weight and immovability to be an inconvenience. These characteristics also often make them unwelcome in rental and lease properties. In addition to weight and immovability issues, though small, there is also the possibility that they will leak. 
     Water mattresses underwent significant change during their popularity. Early water mattresses included nothing more than an envelope or outer skin which contained, but did not control, wave motion of the water. Many users found the undamped motion of the water unpleasant. The industry responded with various products which, to a greater or lesser extent, damped such uncontrolled wave motion. Such products included air filled tubes, baffles extending between the top and bottom panels and fiber inserts, to name but three. 
     Air mattresses which comprise a bladder or envelope filled with air under low pressure now enjoy popularity. Such air mattresses provide obvious benefits relative to a water mattress: significantly lower weight, portability and, though not leak proof, suffer leaks which are far less problematic than water leaks. 
     Another benefit of such mattresses is their ability to be inflated or deflated to suit the personal preference of a user. Devices are available which are selectively controllable by the user to add or release air from the mattress and adjust its firmness. However, they generate excessive and unpleasant sound levels when operating. Such high sound levels are particularly unpleasant when it is noted that such inflating apparatus will most frequently be operated at night when it is relatively quiet. Thus, in a relative sense, while the sound levels of such devices might not be objectionable when used during the day with typically daytime ambient sound levels, during the night, in a bedroom, the high sound levels generated can be noticeable and decidedly unpleasant. 
     The present invention is directed to providing an air mattress inflator/deflator assembly which addresses the problem of high operating sound levels common to prior art inflator/deflator assemblies. 
     SUMMARY OF THE INVENTION 
     An air mattress inflator/deflator assembly includes a cylindrical housing which contains a device for pressurizing the housing, generally a blower and motor. The blower is located near one end of the housing, and pressurizes its interior. One or more valves are selectively operable to direct the pressurized air in the housing to tubing which communicates with an air mattress. The internal pressure of the air mattress can be increased by activating the motor and blower and a valve, pressurizing the housing and directing pressurized air to the air mattress. The internal pressure of the air mattress can be decreased by activating a valve, and releasing air in the air mattress through the housing and out to the ambient. 
     To provide an inflator/deflator assembly for an inflatable mattress that can be easily located beneath a bed or in close proximity thereto, it is necessary to keep the size of the assembly to a minimum. Consequently, the motor and blower are relatively small, and operate at high speed to provide the necessary differential pressure and volume for effective and acceptably rapid inflation of the mattress. A significant drawback of high-speed operation is noise. 
     The present invention reduces the noise associated with operation of the inflator/deflator assembly by enclosing the motor and blower inside a cylindrical housing, and disposing the housing into a close fitting closed cell foam block or surround. The cylindrical shape of the housing eliminates planar surfaces which might sympathetically vibrate and augment noise from operation of the motor and fan. The closed cell foam surround both damps vibration of the housing and suppresses transmission of noise from the housing to the outside environment. The blower draws in ambient air through a sintered metal intake muffler. 
     Thus it is an object of this invention to provide an air mattress inflator/deflator assembly having a housing without flat surfaces that can sympathetically vibrate and transmit noise and vibration from the motor and blower to the ambient. 
     It is a further object of the present invention to provide an air mattress inflator/deflator assembly having a circular housing contained within a foam surround which minimizes noise transmission to the ambient while the assembly is operating. 
     It is a still further object of the present invention to provide an air mattress inflator/deflator assembly having an intake muffler disposed adjacent a blower which produces transmission of operating noise to the ambient. 
     It is a still further object of this invention to provide a quiet air mattress inflation/deflation device that can be used to independently control the air pressure in a single or multiple chamber air mattress. 
     Further objects and advantages of the present invention will become apparent by reference to the following description of the preferred embodiment and appended drawings wherein like numbers refer to the same component, element or feature. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an perspective view of an air mattress and inflator/deflator assembly according to the present invention; 
     FIG. 2 is a full sectional view of an air mattress inflator/deflator assembly according to the present invention; and 
     FIG. 3 is a schematic wiring diagram of an air mattress inflator/deflator assembly according to the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1, an air mattress inflator assembly is illustrated and designated by the reference number  10 . 
     The air mattress inflator/deflator assembly  10  is typically used in conjunction with an air mattress assembly  12  which preferably includes a pair of flexible plastic, typically vinyl, envelopes or bladders  14 A and  14 B which define respective adjacent chambers  16 A and  16 B. On a suitable surface such as a side or end wall of each of the bladders  14 A and  14 B is a respective access fitting  18 A and  18 B which receives and provides communication to a flexible length of hose or tubing  22 A and  22 B. It will be appreciated that the air inflator/deflator assembly  10 , with suitable modifications, may be utilized with an air mattress  12  having a single chamber or an air mattress having 4, 6 or more chambers. 
     Each of the lengths of tubing  22 A and  22 B are terminated in a similar access fitting  24 A and  24 B secured to the inflator/deflator assembly  10 . The access fittings  18 A and  18 B and  24 A and  24 B may define relatively permanently connected devices and include a strap type clamp or may define more readily removable quick connects, e.g., bayonet style latch connectors. Alternatively, the lengths of hose or tubing  22 A and  22 B may be relatively permanently secured at one end to the access fittings  18 A and  18 B or  24 A and  24 B and include quick disconnect fittings at their opposite end. Also extending from the inflator/deflator assembly  10  are a pair of multi-conductor electrical cables  26 A and  26 B which terminate at a like pair of multiple position, momentary contact switches  28 A and  28 B. The switches  28 A and  28 B are preferably disposed adjacent the respective sides of the mattress assembly  12  within easy reach of the users. Finally, a conventional AC power cord assembly  30  including a plug  32  extends from the inflator/deflator assembly  10 . 
     Turning now to FIG. 2, the air inflator/deflator assembly  10  includes an elongate, cylindrical housing  38  defining an interior  40  and having a first inlet end cap  42  and a second, outlet end cap  44 . The cylindrical housing  38  as well as the end caps  42  and  44  are preferably made of PVC and may be like or similar to conventional schedule  40  PVC pipe of sufficient strength to support various components of the assembly  10  as well as possess a reasonable acoustic, i.e., sound deadening properties. In general, housings having thicker walls and made of denser material provide improved sound control but are more costly. It is envisioned that other materials, for example, compressed wood products or fiberglass reinforced plastic, to name but two, would be suitable. The end caps  42  and  44  define flanges  46  and  48 , respectively, which snugly receive and grip the exterior of the cylindrical housing  38 . If desired, the end caps  42  and  44  may be secured to the elongate cylindrical housing by suitable PVC adhesives or radially disposed, removable or non-removable threaded fasteners (not illustrated). 
     Disposed preferably centrally on the inlet end cap  42  is an intake muffler  50 . The intake muffler  50  is sintered metal that is air permeable and is frusto-conical in shape. This allows maximum exterior surface area for air flow, as well as reduction of internally generated noise transfer to the ambient. The intake muffler  50  is a standard device that is often used as an exhaust muffler in compressed air systems. The intake muffler  50  which defines a large plurality of relatively small, convoluted and intersecting passageways reduces noise transmission generated by components of the air inflator/deflator assembly  10  at the inlet where, of course, it must draw air from the ambient. Similar devices such as a tube filled with wadded media or a plurality of perforated baffles, for example, will also achieve the dual goals of air flow and reduced noise transmission. The intake muffler  50  is disposed in a through opening  52  in the end cap  42  and is secured thereto by a threaded fastener such as nut  54  or similar device. The intake muffler includes a centrally disposed outlet passageway  56 . 
     Adjacent the outlet passageway  56  of the intake muffler  50  is a motor and blower assembly  60 . The motor and blower assembly  60  includes a high RPM blower motor  62  which is coupled to and drives a blower wheel  64 . The blower wheel  64  includes an inlet opening  66  which is disposed adjacent the outlet passageway  56  of the intake muffler  50 . A plurality of curved or radial vanes  68  direct air from the inlet opening  66  to the periphery of the blower wheel  64  when it is rotating as will be readily appreciated. The blower motor  62  is supported upon a U-shaped frame  72  which may be secured to a wall of the elongate housing  38  by suitable bolts or other threaded fasteners  74 . When operating, the motor and blower assembly  60  pressurize the interior  40  of the housing  38 . 
     Adjacent the outlet end cap  44  and secured thereto is a solenoid valve assembly  80 . The solenoid valve assembly  80  includes a formed or machined base  82  which is secured to the outlet end cap  44  by a plurality of suitable fasteners  84 . The base  82  positions and supports a pair of solenoid coils  86 A and  86 B which activate respective valve plungers  88 A and  88 B which are maintained in normally closed positions by a respective pair of compression springs  92 A and  92 B. The valve plungers  88 A and  88 B reside within an elongate channel  94  formed in the base  82  which communicates with the interior  40  of the elongate housing  38 . The base  82  also defines a respective pair of outlet ports  96 A and  96 B which communicate with the respective lengths of tubing  22 A and  22 B through the outlet fittings  24 A and  24 B. 
     Referring now to FIGS. 1 and 2, the inflator/deflator assembly  10  also includes a foam block or surround  100 . The foam surround  100  is somewhat longer than the housing  38  and defines a through opening  102  having a diameter just slightly smaller than the outside diameter of the housing  38 . Accordingly, the foam surround  100  snugly receives the housing  38  and, though removable, is retained thereabout without the use of adhesives or other securement means. At the end of the foam surround  100  adjacent the intake muffler  50  is a circular foam disc  104  having an outside diameter just slightly larger than the diameter of the through passageway  102 . The foam disc  104  also defines a small through passageway  106  having a diameter larger than the outside diameter of the intake muffler  50 . 
     The foam disc  104  closes off a major portion of the otherwise open end of the foam surround  100  adjacent the inlet end cap  42  and intake muffler  50  as will be readily appreciated. The foam surround  100  and foam disc  104  are preferably made of closed cell polyurethane foam. The foam surround  100  and foam disc  104  provide noise reduction by damping the external surface of the housing  38  and inlet end cap  42  and providing a vast number of closed cells or pockets which reduce sound transmission from the housing  38 . Furthermore, the foam surround  100  raises the housing  38  off any supporting surface thereby minimizing the transmission of sound to any building components that might sympathetically vibrate. For example, if the foam surround  100  were absent, while carpeting would not present a difficulty, if the housing  38  were placed directly upon a bare wood or vinyl floor covering surface, noise transmission and thus generation would be significant and likely objectionable. 
     It should be noted that while the foam surround  100  illustrated is square in cross section, other cross sections such as round, triangular, pentagonal, hexagonal and the like or irregular surface treatments such as projections and recesses may also be utilized. Preferably, the minimum wall thickness of the foam surround  100  will be approximately one inch. Also, the foam surround  102  may be lengthened such that a second circular disc is disposed adjacent the outlet end cap  44 . However, since the outlet end cap  44  is somewhat distant from the motor and blower assembly, the solenoid valve assembly is secured to the outlet end cap  44  thereby minimizing uncontrolled diaphragm-like vibrations of the end cap  44  and, lastly, because of the number and position of the interconnecting cables and hoses, it has been found that such a second foam disc has a minimal effect on sound level reduction. 
     Turning then to FIG. 3, the electrical wiring diagram of the air inflator/deflator assembly  10  is illustrated. As noted, a conventional electrical plug  32  provides electrical energy through a multiple conductor cable  30 . A thermostatic safety switch  112  disposed in the interior  38  of the elongate housing  40  opens the electrical circuit thereby inhibiting operation of all of the electrical components when the temperature within the housing  38  exceeds a preset limit. Assuming the temperature limit control  112  is closed, electricity is provided to the center or common pair of contacts  114 B 1  and  114 B 2  of the momentary contact switch  28 B which is a double pole, double throw type. 
     The momentary contact switch  28 B includes a first pair of isolated, aligned contacts  116 B 1  and  116 B 2  on one side of the center or common contacts  114 B 1  and  114 B 2  and a second pair of aligned contacts  118 B 1  and  118 B 2  on the opposite side of the center contacts  114 B 1  and  114 B 2 . 
     A pair of sliding wipers  120 B 1  and  120 B 2  are biased by springs (not illustrated) into center, normally off positions illustrated in FIG.  3  and electrically connect the center contacts  114 B 1  and  114 B 2  to the first pair of contacts  116 B 1  and  116 B 2  when they are moved to the left or the second pair of contacts  118 B 1  and  118 B 2  when they are moved to the right, as those familiar with center off, momentary contact, double pole, double throw switches will readily appreciate. 
     When the sliding wipers  120 B 1  and  120 B 2  are moved to the right, the contact  118 B 2  is energized and a conductor  122 B provides electrical energy to the solenoid valve  86 B, opening it. The open solenoid valve  86 B allows air under low pressure in the bladder  14 B to flow back into the interior  40  of the housing  38  and exhaust through the intake muffler  50 , thus lowering the pressure and reducing the firmness of the bladder  14 B on one side of the air mattress  12 . When the switch  28 B is released, the wipers  120 B 1  and  120 B 2  are returned to the positions illustrated in FIG.  3  and the valve  86 B closes, maintaining the level of air pressure and thus firmness of the bladder  14 B of the air mattress  12 . 
     When the sliding wipers  120 B 1  and  120 B 2  are moved to the left as illustrated in FIG. 3, electrical energy is provided to the contact  116 B 2 , through the conductor  122 B to the solenoid valve  86 B and also to the contact  116 B 1  and through a conductor  124  to a diode or half-wave rectifier  126 . The diode or half-wave rectifier  126  reduces the voltage applied to the blower motor  62  by 50% and thus reduces significantly its operating speed and sound generation. An electrical conductor  128  is coupled to the plug  32 . 
     The momentary contact switch  28 A includes a pair of isolated, aligned contacts  116 A 1  and  116 A 2  on one side of the center or common contacts  114 A 1  and  114 A 2  and a second set of aligned contacts  118 A 1  and  118 A 2  on the opposite side of the center contacts  114 A 1  and  114 A 2 . An electrical conductor  122 A connects the switch contacts  116 A 2  and  118 A 2  with the solenoid valve  86 A. 
     Operation of the switch assembly  28 A is the same as operation of the switch assembly  28 B, as will be readily appreciated, except that its operation affects the pressurization and release of air from the other bladder  14 B of the air mattress  12 . Thus, it will be appreciated that individual control of the firmness/softness of each envelope or bladder  14 A and  14 B is achievable by operation of the air mattress inflator/deflator assembly  10  according to the present invention. 
     As noted, one of the significant design goals of the air mattress inflator/deflator assembly  10  of the present invention is reduced operating noise level relative to presently available similar products. The following Table I sets forth the results of sound level testing undertaken on various products. The sound level meter was placed 12 inches from each unit when it was operating in the inflate mode. Neither hoses nor mattresses were coupled to the devices during the sound level measurements. 
     
       
         
               
               
               
             
           
               
                   
                 TABLE I 
               
               
                   
                   
               
               
                   
                 PRODUCT UNDER TEST 
                 SOUND LEVEL (dbA Scale) 
               
               
                   
                   
               
             
             
               
                   
                 Competitive Product A 
                 88 
               
               
                   
                 Competitive Product B 
                 80 
               
               
                   
                 Sample 1 
                 65 
               
               
                   
                 Sample 2 
                 68 
               
               
                   
                   
               
             
          
         
       
     
     Thus, in operation, an air inflator/deflator assembly  10  according to the present invention exhibits noise levels 12 to 23 db lower than currently available competitive products. This is a significant benefit and overcomes a complaint frequently raised by users of such products. 
     The foregoing disclosure is the best mode devised by the inventor for practicing this invention. It is apparent, however, that apparatus incorporating modifications and variations will be obvious to one skilled in the art of air mattress inflating devices. Inasmuch as the foregoing disclosure presents the best mode contemplated by the inventor for carrying out the invention and is intended to enable any person skilled in the pertinent art to practice this invention, it should not be construed to be limited thereby but should be construed to include such aforementioned obvious variations and be limited only by the spirit and scope of the following claims.