Abstract:
A sauna comprises a radiant heating element for supplying heat to the interior of a sauna cabinet. A cover is disposed between the radiant heating element and the interior, and has multiple openings sized to prevent the insertion of a finger.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     This application is a continuation-in-part of U.S. patent application Ser. No. 11/465,903, filed Aug. 21, 2006, and claims priority on U.S. Patent Application No. 60/746,214, filed May 2, 2006, with the disclosure of both applications being incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates generally to sauna with a radiant heater, and more particularly to an infrared emitter unit for a sauna.  
         [0004]     2. Description of the Related Art  
         [0005]     Saunas are popular devices used by many individuals for relaxation and other health benefits, such as stress relief, pain relief, improved blood circulation, strengthened cardiovascular system, and improved skin appearance. Conventional saunas comprise a closed room having a heat source for supplying heat to the room and to the sauna user. Generally, a sauna is one of two types—a “wet” sauna that utilizes heated steam as the heat source and a “dry” sauna that utilizes a heat source with little or no steam.  
         [0006]     Infrared saunas, sometimes referred to as far infrared (FIR) saunas have gained popularity as an alternative to traditional dry saunas. Infrared saunas employ an infrared radiant heating mechanism instead of rocks warmed by an electric heater as used in traditional dry saunas, such as the Finnish sauna. Infrared heating mechanisms typically comprise an infrared emitter that can become extremely hot as the sauna is heated to an operating temperature, which can range from 100° F. to 190° F. The infrared heaters are normally accessible by the user and the user should be protected from accidental contact with the heating elements of the infrared heater.  
       SUMMARY OF THE INVENTION  
       [0007]     According to one aspect of the present invention, a sauna comprises a cabinet defining an interior and having an opening providing access to the interior, a door mounted to the cabinet and moveable between a closed position, where the door blocks human access from an exterior of the cabinet through the opening to the interior, and an open position, where human access is permitted from the exterior through the opening to the interior, a radiant heating element supplying heat to the interior, and a cover disposed between the radiant heating element and the interior and having multiple openings, each opening having an effective size to prevent the insertion of a child&#39;s finger having a standard size.  
         [0008]     In one embodiment, the effective size is less than 0.3 inches. The effective size can be ¼ inch.  
         [0009]     In another embodiment, the radiant heating element comprises an infrared emitter.  
         [0010]     In yet another embodiment, the openings are hexagonal. The hexagonal openings can have a maximal diameter of ¼ inch.  
         [0011]     In still another embodiment, the sauna can further comprise a housing mounted to the cabinet and in which the radiant heating element is located, with the housing having a rear wall from which extends a multifaceted peripheral side wall, with each facet extending an angle greater than 90° from the rear wall. The cover can have an open area that is greater than 65%. The radiant heating element can be an infrared emitter.  
         [0012]     In a further embodiment, the cover has an open area that is greater than 65%, The open area can be at least 79%.  
         [0013]     According to another aspect of the invention, a sauna comprises a cabinet defining an interior and having an opening providing access to the interior, a door mounted to the cabinet and moveable between a closed position, where the door blocks human access from an exterior of the cabinet through the opening to the interior, and an open position, where human access is permitted from the exterior through the opening to the interior, a radiant heating element for supplying heat to the interior, and a cover disposed between the radiant heating element and the interior and having multiple openings, and having an open area that is greater than 65%. The open area can be at least 79%.  
         [0014]     In another embodiment, the each opening has an effective size that is less than 0.3 inches. The effective size can be ¼ inch. The openings can be hexagonal.  
         [0015]     In yet another embodiment, the radiant heating element is an infrared emitter.  
         [0016]     According to yet another aspect of the invention, a sauna comprises a cabinet defining an interior and having an opening providing access to the interior, a door mounted to the cabinet and moveable between a closed position, where the door blocks human access from an exterior of the cabinet through the opening to the interior, and an open position, where human access is permitted from the exterior through the opening to the interior, and a heat source comprising a housing having a rear wall from which extends a multifaceted peripheral side wall, with each facet extending an angle greater than 90° from the rear wall, a radiant heating element located within the housing and supplying heat to the interior, and a cover disposed between the radiant heating element and the interior and having multiple openings.  
         [0017]     In one embodiment, the multifaceted peripheral side wall comprises two spaced side facets and two spaced end facets joining the two side facets. At least two facets can be oriented at a different angle with respect to the rear wall.  
         [0018]     In another embodiment, the facets extend from the rear wall at an angle between 115° and 150° degrees.  
         [0019]     In yet another embodiment, the cover has an open area that is greater than 65%.  
         [0020]     In still another embodiment, the radiant heating element is an infrared emitter.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0021]     In the drawings:  
         [0022]      FIG. 1  is a perspective view of a sauna, with the doors open to illustrate the interior of the sauna.  
         [0023]      FIG. 2  is a front perspective schematic illustration of an infrared emitter unit according to the present invention.  
         [0024]      FIG. 3  is a side perspective schematic illustration of the infrared emitter unit from  FIG. 2 .  
         [0025]      FIG. 4  is a partial cross-section view through line  4 - 4  of  FIG. 2 .  
         [0026]      FIG. 5  is a partial cross-section view through line  5 - 5  of  FIG. 2   
         [0027]      FIG. 6  is a close-up view of a screen for the infrared emitter unit from  FIG. 2 . 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0028]     Referring now to the drawings, and in particular to  FIG. 1 , an illustrative example of a sauna  10  is shown comprising a heat source shown as an infrared emitter unit  40 . The sauna  10  comprises a substantially box-like structure defining an interior space  12 . The exterior walls of the sauna  10  are preferably made of wood. The sauna  10  is provided with a pair of doors  14  that are openable to permit entrance into the interior space  12  of the sauna  10 . The doors  14  can comprise a wooden frame  16  supporting a tempered glass panel  18  and a handle  20 .  
         [0029]     The side walls, floor panel, and ceiling panel of the interior space  12  are preferably covered with or constructed of multiple slats  22  of unfinished wood, such as birch cedar, redwood, hemlock, aspen and white spruce. The interior space  12  can further comprise other elements that are not germane to the invention, such as a hanging rod  24  for hanging items within the interior space  12 , a user interface  26  for controlling the operation of the sauna  10 , a bench  28  allowing one or more users to sit in the interior space  12 , and various other elements common to saunas.  
         [0030]     The sauna  10  is suited for incorporation into static structures, such as houses, apartments, condominiums, hotels, gyms, and other buildings, and also mobile structures, such as recreational vehicles (RVs), trailers, mobile homes, cruise ships, and houseboats.  
         [0031]     The sauna of  FIG. 1  is for illustrative purposes only and is not limiting on the invention. The structure and construction of the sauna is not germane to the invention. Any sauna structure can be used.  
         [0032]     Referring to  FIGS. 2 and 3 , the infrared emitter unit  40  comprises a housing  42 , at least one infrared emitter  44 , and a cover  46 . Other elements not illustrated, but that can be included with the infrared emitter unit  40  include reflectors, controls, thermostats, wiring, and other elements common to infrared emitter units. The infrared emitter unit  40  is provided to heat the interior space  12  and/or a sauna user. As is known in the dry sauna art, the infrared emitter unit  40  emits far infrared ray radiation.  
         [0033]     In the illustrated embodiment, the infrared emitter unit  40  is recessed in an interior side wall of the sauna  10  and emits radiation inwardly toward the interior space  12 . The infrared emitter unit  40  is shown positioned on an interior side wall of the sauna  40 , however, the location of the infrared emitter unit  40  can be varied. The sauna  10  can further be provided with more than one infrared emitter unit  40 . The infrared emitter unit  40  can be partially covered by a wooden frame  30  crossed by generally horizontal slats  32  attached to the frame  30  to reduce or minimize direct contact between the user and the screen  46  that might otherwise deform or deflect the cover  46 . The wooden frame  30  and slats  32  can also be configured as a back rest for the user in the event that the infrared emitter unit  40  is position behind the bench  28 . However, it is desirable to minimize the number of slats as they will limit the transfer of heat into the sauna.  
         [0034]     The housing  42  has an open face formed by a rear wall  48  from which extends a multifaceted peripheral side wall  50 . As illustrated, the peripheral side wall  50  comprises a right side facet  52 , a left side facet  54 , a top facet  56 , and a bottom facet  58  joined together to form a generally box-like structure. A flange  60  extends from the peripheral side wall  50  such that it is generally parallel to the rear wall  48  and surrounds the open front face of the housing  42 .  
         [0035]     Referring to  FIG. 4 , the right and left side facets  52 ,  54  are spaced from one another and meet the rear facet  48  at an angle α that is equal to or greater than 90°. Likewise, referring to  FIG. 5 , the top and bottom facets  56 ,  58  are spaced from one another and meet the rear facet at an angle β that is equal to or greater than 90°. Preferably, angles α and β are greater than 90°. More preferably, angles α and β range from 115° to 150°. The angled peripheral side wall  50  increases the efficiency of the infrared heater unit  40 , as compared with a heater unit having a housing with walls joined at right angles, because more heat is reflected through the opening into the interior space, resulting in less heat buildup at the angled peripheral side wall  50  as compared to the currently used side wall.  
         [0036]     In the illustrated embodiment, the infrared emitter unit  40  comprises two infrared emitters  44 , however, the infrared emitter unit  40  may comprise one emitter  44 , or multiple emitters  44 . The infrared emitter  44  can be a ceramic emitter, a steel (Incoloy) rod heater, or any other type infrared emitter known in the infrared sauna art. It is also within the scope of the invention to employ other non-infrared radiant heating elements to supply heat to the interior space  12 .  
         [0037]     The cover  46  is disposed between the infrared emitters  44  and the interior space  12  and prevents a user from directly contacting the infrared emitters  44 . In the illustrated embodiment, the cover  46  overlies the open front face  62  of the housing  42 . The cover  46  can be mounted to the flange  60  using suitable fasteners, such as screws or bolts  64 . The cover  46  is preferably made of a metal, for example, steel, galvanized steel, stainless steel, monel (alloy of nickel, copper, iron, and other trace elements), brass, copper, aluminum, zinc, or tin. The cover  46  is preferably made from galvanized steel.  
         [0038]     Referring to  FIG. 6 , a close-up view of the screen  46  is illustrated. The cover  46  has multiple openings  66  having an effective size that prevents an anticipated user, even a child user, from inserting a finger through one of the openings  66 . The effective size can be described in terms of an effective diameter, which is defined as the maximal diameter that can be measured between two points of the opening. It has been determined that 0.3 inches represents a standard minimum finger size of an anticipated user. This is approximately the diameter of a standard No. 2 pencil. Thus, the effective size is preferably less than 0.3 inches. More preferably, the effective size is ¼ inch.  
         [0039]     In the illustrated embodiment, the openings  66  are hexagonal and form a honeycomb-like pattern. Each hexagonal opening  66  has a maximal diameter D H  measured between two opposing vertices of the hexagon and an area A H . Preferably, the diameter D H  is less than 0.3 inches. More preferably, the diameter D H  is ¼ inch.  
         [0040]     Another important dimension of the cover  46  is the thickness T of the material between adjacent openings  66 . The thickness T can be uniform or can vary across the cover  46 . The thickness T of the cover  46  should be chosen so that the cover  46  can withstand anticipated pressures without deforming. The material used for the cover  46  is also a consideration when determining a suitable thickness T, since a cover  46  made from a stronger material can have a smaller thickness T and still withstand anticipated pressures without deforming.  
         [0041]     In addition to preventing a user from contacting the heating elements, the cover should block as little heat as possible to minimize heat build up in the housing and maximize the heat transferred into the sauna. To accomplish these conflicting goals, the cover  46  has an open area, which can be quantified as the percentage of open area in the cover relative to the total area, and is directly related to the heat radiation efficiently of the infrared heater unit  40 . The open area can be determined by dividing the total sum of the areas of the openings  66  in the cover  46  by the area of the cover. The open area is also affected by the thickness T of the cover  46 .  
         [0042]     A large open area is desired in order to most efficiently transfer heat into the sauna, and this is most effectively accomplished by maximizing the area of each opening  66  and minimizing the thickness T. However, the area of each opening  66  can only be maximized up to a certain point for safety concerns, since the effective size is preferably less than 0.3 inches to prevent the anticipated user from inserting a finger through one of the openings  66 . Another safety concern arises when minimizing the thickness T. If the thickness T becomes too small, pressure on the cover  46  may deform or break the cover  46  and possibly allow contact with the infrared emitter  44 . Therefore, the open area of the cover  46  must be optimized with a suitable effective size of the openings  66  and thickness T.  
         [0043]     Preferably, the cover  46  has an open area that is greater than 65%. More preferably, the cover  46  has an open area that is at least 79%. For a cover  46  comprising hexagonal openings  66  having a diameter D H  of ¼ inches and a thickness T of about 0.04 inches, the open area was determined to be 79%.  
         [0044]     While the cover  46  is illustrated as having hexagonal openings  66 , it is understood that other shapes can be used. Examples of suitable opening shapes for the cover  46  include triangles, squares, rectangles, diamonds, pentagons, octagons, circles, ovals, ellipses, clovers, or a mixture thereof. The cover  46  can also comprise an opening pattern comprising a mixture of opening shapes and sizes of opening shapes. The openings  66  can also be arranged to be irregular or non-repeating.  
         [0045]     The infrared heater unit insures the safety of users by employing a cover over the infrared emitter having openings of a effective size that prevents a user from inserting a finger through the cover. However, the open area of the cover and the housing shape still provides an efficient heating of the sauna interior.  
         [0046]     While the invention has been specifically described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation, and the scope of the appended claims should be construed as broadly as the prior art will permit.