Abstract:
A personal warming apparatus includes of a chimney having an open top end, an open bottom end, an inner wall, an outer wall, and an insulating liner. A heating element is disposed within the chimney, and the chimney is suspended in an elevated position from a support system.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     None. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to a heating apparatus, and more particularly pertains to a sportsman&#39;s furnace which can be used with or mounted to pre-existing seats. 
     Sportsmen have always suffered under the elements while participating in various outdoor activities, including hunting and fishing. Many of these activities occur in the fall or winter months when the weather has turned cold. Various devices have been proposed to alleviate this problem. Seat warmers, portable heaters, and various hand and foot warmers have been proposed. The heating devices belong to one of two general styles, reflective heating devices and active heating devices. 
     A number of disadvantages are associated with these devices. Reflective heating devices do not provide an active source of heat. They rely on heat escaping from a person&#39;s body to warm the person. Additionally, these devices only warm the area of the person&#39;s body directly in contact with the reflective device. Thus, they are limited as to how quickly they will warm someone and the level of warmth which will be provided to the user. This style of heating device does not provide overall warming to the user because the air which surrounds the person is at ambient temperature. Reflective heating devices are inadequate since uncomfortableness from being cold cannot be remedied by warming only one part of a person&#39;s body if the rest of the person&#39;s body is cold. 
     The second main type of heating device, active heating devices, include space heaters and personal heating devices. Space heaters are designed to heat an entire enclosure, not just the individual user. Space heaters require that the person be situated inside an enclosure, otherwise heat is lost to the atmosphere. The result is that a large amount of heat is required from the heater to efficiently warm an individual. Additionally, a large amount of fuel must be carried with the heater to provide adequate warmth to the user, and the large amount of heat produced creates a hazard when operating the heater near combustible materials. 
     Personal heating devices have been developed which are designed to provide an active heating source and direct the heat so as to warm a person directly, as opposed to warming a spatial area. Some of these devices warm a sitting surface or a particular part of someone&#39;s body. Examples of this type of heater are chemical hand and foot warmers. Chemical heating devices operate by providing direct contact between a user&#39;s body and a heated surface. A bag or pouch contains chemicals which react to produce heat. The outside of the bag or pouch is placed next to the user&#39;s skin to transfer heat generated by the chemical reaction to the user. In these devices, the user&#39;s own body may also serve to block or obstruct the flow of heat to the rest of the body. Additionally, direct contact between a person&#39;s body and a heated surface requires that the surface be sufficiently insulated or that its temperature be kept sufficiently low so as to avoid discomfort or burning to the user. Chemical heaters typically generate heat for only a short amount of time, due to the limited amount of chemicals which can be contained in the pouch. 
     Other portable heating devices have been developed which have been designed to provide a seating surface positioned above a heat source and a heated air passageway, which allows the heated air to be directed so as to surround the user. Additional features, such as a coat or poncho have been used to facilitate the directing of the heated air. These portable devices have heating elements inserted into buckets with seats attached to the top of the buckets. Many of these devices provide both cooking and seating surfaces, and as a result, they are not particularly well-suited to the singular purpose of warming a person. Additionally, the portable seat type heater is often too cumbersome or unwieldy to use. The design of the heater is such that it necessarily must be placed on the floor. This limits the flexibility of the heater as to when and where it can be used. The awkwardness of the seat type heater is usually a result of the activity for which it is being used. The activity in which the user is participating may provide a seat that will not allow the efficient use of the portable seat. Many deer hunting stands, fishing boats, spectator sporting events, and other similar activities have seats built into the tree stand, boat, bleacher, etc. which does not permit practical or safe use of a portable heating seat. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention relates to a sportsman&#39;s furnace for use in various sporting activities such as deer hunting, fishing, spectator sports, and other outdoor activities. The furnace is an insulated housing with a fuel source attached. A chimney directs the heated air up and around the participant. 
     A preferred embodiment of the invention allows the furnace to be used in conjunction with a pre-existing seat. The furnace is mounted to the pre-existing seat using a support system. The tube which directs the heat is insulated to prevent burning and reflective on the inside to direct all heat to the user. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cutaway perspective view of one embodiment of the invention. 
     FIG. 2 is an exploded view of one embodiment of the linkage system. 
     FIG. 2A is a side view of an alternate embodiment mounting bracket. 
     FIG. 3 is a perspective view of one embodiment of the inventive furnace mounted to a tree stand. 
     FIG. 4 is a side view of one embodiment of the inventive furnace mounted to a pre-existing pedestal seat. 
    
    
     DETAILED DESCRIPTION 
     The present invention is a sportsman&#39;s furnace indicated generally at  10  in FIG.  1 . The furnace  10  includes a chimney  12 , a linkage  14 , a bracket  16 , a burner assembly  18 , a propane tank  20 , and a mounting stand  22 . 
     The chimney  12 , includes an inner layer  24 , an outer surface layer  26 , and a middle layer  28 . A top rim  27  defines where the majority of warmed air is exhausted from the chimney  12 . The inner layer  24  forms an inner wall of the chimney  12 . In the embodiment shown in FIG. 1, the material used for the middle layer  28  is poly vinyl chloride (PVC) tubing. This provides a stable, affordable, strong, lightweight material, which can easily be worked with during the manufacturing of the furnace  10  and is able to maintain its properties at the temperatures required for the invention. Other materials may be used for the chimney  12 , including a class B aluminum gas vent. Any material, however, which provides the desired strength, provides the desired insulating capabilities at the required temperatures, and is lightweight so as to be easily transported may be used as the chimney  12 . 
     In this embodiment, inner layer  24  is fiberglass insulation with a reflective covering. This material is known to those skilled in the art, and is commercially available. The inner layer  24  is secured to the middle layer  28  of the insulating chimney  12  by friction fit, but alternatively may utilize an adhesive between the middle layer  28  and the inner layer  24 . 
     The reflective and insulating properties of the inner layer  24  prevent the transferral of heat generated by the burner assembly  18  through the wall of the insulated chimney  12 . Very little heat is thermally conducted through the insulated chimney  12 . Therefore, the outer surface layer  26  remains at or near the ambient temperature of the surrounding air. In the preferred embodiment, the reflective inner layer  24  extends over the top rim  27  of the chimney  12  insulating the remainder of the chimney  12 , (including the outer layer  26 ) from the warmed air being exhausted. 
     The optional outer surface layer  26  is a fabric layer secured to the middle layer  28  of the chimney  12 . The fabric used for the outer surface layer  26  can have a variety of patterns. Camouflage patterns or blaze orange may be used for the outer layer  26  of the invention if it is to be used in a hunting application. Any style or design of fabric, however, can be provided with the invention to achieve various aesthetic effects including placing company logos or pictures on the fabric. For the inventive embodiment shown in FIG. 1, the outer layer  26  can optionally be excluded from the invention, since the inner layer  24  provides the insulation and reflecting functions. Alternate embodiments may utilize insulation in any of the chimney layers. 
     The overall length of the chimney is approximately eight to ten inches. The chimney is designed to accommodate a minimum of fifteen inches clearance between the floor and average seat height, while allowing one inch minimum clearance at the floor end. Enough distance is allowed from the top of the chimney  12  to the underside of any seat under which the invention may be positioned to prevent over-heating and combustion of the seat material. The diameter of the chimney  12  is approximately six to ten inches. These length and diameter dimensions allow the user to generate and direct enough heated air to warm the user, while maintaining a small enough profile to allow the furnace  10  to be placed below the user without getting in the way of the user&#39;s legs. A baffle (not shown) may additionally be mounted above the chimney  12  to further direct heated air. 
     The chimney  12  design prevents the sides of the chimney  12  from becoming hot and burning the user or igniting any combustible materials that comes in contact with the insulated chimney  12 . Heated air emitted from the top of the chimney  12  is allowed enough room to sufficiently cool so as to provide a comfortable level of heat to the user. Additionally, the chimney  12  acts as a guard around the burner assembly  18  to prevent the heat from the burner assembly  18  from coming in contact with any combustible material, while concentrating and directing heated air where the user desires. 
     By raising the chimney from the ground, and keeping the bottom of the insulated chimney  12  open, the sportsman&#39;s furnace  10  maintains a safe environment for use of combustible fuel. For example, if propane is used as the fuel, any unburned propane during the lighting stages or if the flame from the burner assembly  18  is extinguished, will fall through the bottom of the insulated chimney  12  and disperse. This prevents a “fireball” from occurring if the propane is left to run and the user attempts to light the burner assembly  18 . Although the preferred embodiment depicts the use of the linkage system  14  to elevate the chimney  12 , a person skilled in the art would realize that any number of structures may be used to support the chimney  12  (i.e. a stand to support the propane bottle  20 , such as those found commercially available). Additionally, the natural draw from the rising hot air is enhanced by the open ends and elevated position of the insulated chimney  12 . Fresh air is drawn from below the chimney  12  and heated air is discharged out the top. This encourages a complete burning of the fuel, and prevents carbon monoxide poisoning, as no sealed combustion chamber exists. 
     The use of an open chimney  12  (both top and bottom) simplifies the design and results in less manufacturing costs than a furnace which requires a base and cover. By concentrating and directing the heated air, the chimney  12  cuts down in the amount of heat that must be generated, which reduces the noise produced by the furnace  10  and the possibility that the heated air could ignite nearby flammable materials. Noise is a primary concern when the furnace  10  is used in hunting applications. Although eight to ten inches length and six to ten inches diameter is the preferred embodiment of the chimney  12 , alternate embodiments may utilize different length and diameter dimensions and still remain within the scope of the invention. Additionally, although FIG. 1 shows the chimney  12  formed in a tube with a circular cross-section, any shape is acceptable including square, rectangular, or hexagonal. 
     The insulating chimney  12  is mounted to a bracket  16  typically using bolts and nuts. The bracket  16  in the preferred embodiment is manufactured from a light-weight metal such as aluminum. However, any rigid material which is strong enough to support the weight of the chimney  12 , burner assembly  18  and propane tank  20 , may be used. This may include a rigid plastic, steel, or other like material. The bracket includes an upper edge  29  and a lower edge  31 . The bracket  16  is formed so as to accept the propane tank  20 . The propane tank  20  used in the embodiment shown in FIG. 1, is a pressurized tank holding approximately one pound of fuel and is disposed in a longitudinal fashion parallel to the outer layer  26  of the chimney  12 . The tank  20  is available commercially at many sporting goods stores. Although the embodiment of the invention shown in FIG. 1 shows the propane tank  20  as a one pound tank, a person skilled in the art will realize the bracket  16  may be designed to accommodate various tank sizes or shapes. 
     The bracket  16  is disposed proximate to where the burning assembly  18  enters into the chimney  12 . The burning assembly  18  includes a valve  30 , a feed tube  32 , and a burner  34 . The valve  30  mounts to the outlet of the propane tank  20 . The valve  30  includes an adjusting knob  36  which allows the user to vary the amount of fuel which runs through the burner assembly  18 , thereby adjusting the amount of heat produced by the furnace  10 . The valve  30  is commercially available and of the type which fits on the one pound propane fuel tank  20 . In the preferred embodiment, a direct pressure valve is used which allows for adjustment of the fuel at low flow levels. 
     The feed tube  32  extends horizontally from the valve  30  through an aperture  38  in the insulated chimney  12 . The feed tube then extends through a first curve  40  and then downwardly, proximate and substantially parallel to the inner wall of the chimney  12 . Once the tube reaches below the bottom of the insulating chimney  12  approximately one and one quarter inches, it extends through a second curve  42 , directing the feed tube  32  upwardly and substantially parallel to the inner wall of insulating chimney  12 . Directing the feed tube  32  below the chimney  12  has the desirable effect of maintaining a set amount of space between the floor and the bottom of the chimney  12 . The feed tube is typically brass (although a person skilled in the art will realize that alternate materials may be used). Although the preferred embodiment extends the feed tube  32  through the chimney  12  before extending through the first curve  40 , an alternate embodiment of the invention can exist. For example, the tube may be disposed parallel to the outside of the chimney  12  before extending through the second curve  42  up into the chimney  12 . 
     The burner  34  is mounted to the upwardly extending feed tube  32 , typically by threading the burner  34  onto the feed tube  32 . The burner  34  is a low flow type, is known in the art, and is commercially available. Using a low flow burner  34  limits the amount of heat which is generated, allowing the heater to be fine tuned by the valve  30 . The low flow, low BTU (British Thermal Unit) burner  34  also produces very little noise, an advantage in hunting applications. The low heat production also serves to prevent combustion of any ignitable materials which are in the proximity of the furnace  10 , providing an additional factor of safety to the heater  10 . The upper limit of the average operating temperature is approximately 150 degrees Fahrenheit. The burner  34  is mounted so as to be disposed approximately along the axis of the chimney  12  approximately two to four inches from the bottom of the chimney  12 . Placement of the burner  34  in this location directs a small portion of the heat downward out the bottom of the chimney  12 , allowing the user to warm his or her feet under the chimney  12 . 
     To operate the furnace  10 , the user turns on the valve  30  allowing propane to flow through the feed tube  32  to the burner  34 . The propane which is issuing through the burner  34  is ignited typically using a piezoelectric device  43 A although a person skilled in the art would realize any device which issues a flame or a spark may be used to ignite the burner  34 . The piezoelectric device  43 A is a separate attachment which is placed in a holding slot  45  in the bracket  16 . Alternatively, an integral piezoelectric device  43 B (shown in dotted lines) may be provided as part of the invention. After the burner  34  has been ignited, the user may adjust the amount of heat generated by the furnace  10  by adjusting the valve  30  controlling the amount of fuel sent to the burner  34 . 
     The linkage  14  maintains the chimney in an elevated position, and is mounted to the bracket  16  typically using bolts and nuts. Wing nuts (not shown) may be used to allow convenient attachment and unattachment of the linkage  14  to the bracket  16 . Mounting the linkage  14  to the bracket  16  in this manner balances the weight of the tank  20  with the weight of the chimney  12 . In the embodiment shown in FIG. 1, the linkage system  14  (further discussed with respect to FIG. 2) terminates and is mounted to a mounting stand  22 . The mounting stand  22  (or floor plate), includes a flat base, rectangular in shape, measuring approximately 11 ¾ inches along one dimension by approximately 11 ⅛ inches in the second dimension. Although the preferred embodiment uses the above dimensions, any size plate which provides enough stability for the sportsman&#39;s furnace  10  to prevent the weight of the insulated chimney  12 , bracket  16 , burner assembly  18 , propane tank  20 , and linkage system  14  from tipping over the sportsman&#39;s furnace  10  may be used. In the preferred embodiment, the mounting stand  22  is manufactured from a hard plastic, however any rigid material with adequate strength may be used, including wood, metal, or composite materials. The mounting stand  22  also includes a flat mounting bracket  44  mounted to the mounting stand  22  typically using screws  46 . 
     The preferred embodiment of the linkage system  14  is shown in FIG.  2 . The linkage system  14  is comprised of a base link  48 , a middle link  50  and a bracket link  52 . The base link  48  has a lower end  53  and an upper end  55 . The lower end  53  is disposed proximate to the flat mounting bracket  44 . The flat mounting bracket  44  is coupled to the lower end  53  of the base link  48  by a coupling pin  54 . The coupling pin  54  is threaded into the flat mounting bracket  44 . The base link  48  is disposed on the coupling pin  54  so that the coupling pin  54  extends into a cavity  56  in the base link  48 . A cotter pin  58  is extended through a first aperture  59 A in the base link  48 , further through a bore  61 A in the coupling pin  54  and finally through a second aperture  59 B in the base link  48  so that the cotter pin  58  effectively locks the coupling pin  54  inside the base link  48 . By connecting the flat mounting bracket  44  to the base link  48  in this fashion, the base link  48  is able to rotate about its central axis. Rotation is allowed by partial threading and unthreading the coupling pin  54  with respect to the flat mounting bracket  44 . 
     The upper end  55  of the base link  48  is connected to the middle link  50  using a first hinge pin  60  and a first nut handle  62 . The middle link  50  contains a base end  64  and a bracket end  66 . Bores  61 B and  61 C run through the upper end  55  of the base link  48 , and the base end  64  of the middle link  50 . The upper end  55  of the base link  48  additionally contains a first notch  68 . The first notch  68  extends from the upper end  55  of the base link  48  approximately ¾ of an inch towards the lower end  53  of the base link  48 . The upper end  55  of the base link  48  is rounded in shape. This rounded shape allows for the pivoting motion of the base link  48  with respect to the middle link  50 . The base end  64  of the middle link  50  is designed to be the same shape as the upper end  55  of the base link  48 . The base end  64  contains a second notch  70  and the base end  64  is rounded in shape. The first notch  68  on the base link  48  is mated with the second notch  70  on the middle link  50 . The first hinge pin  60  is extended through the bore  61 B in the base link  48  and then further through the bore  61 C in the middle link  50 . The first nut handle  62  is threaded onto the first hinge pin  60 . By tightening or loosening the first nut handle  62  on the first hinge pin  60 , the user is able to alternatively lock or unlock the position of the middle link  50  with respect to the base link  48 . 
     Bores  61 D and  61 E extends through the bracket end  66  of the middle link  50 . A slot  72  extends from the bracket end  66  of the middle link  50  towards the base end  64 . The slot  72  extends for approximately one inch. The bracket link  52  includes a linkage end  74  and a heater end  76 . Aperture  59 C extends through the linkage end  74 . The linkage end  74  of the bracket link  52  is extended into the slot  72  of the bracket end  66 . A second hinge pin  78  extends through the bore  61 E in the bracket end  66  of the middle link  50 , continues through the aperture  59 C in the linkage end  74  of the bracket link  52  and finally further through the second bore  61 D in the bracket end  66  of the middle link  50 , pivotally connecting the bracket link  52  to the middle link  50 . A second nut handle  80  is threaded onto the second hinge pin  78 , allowing the user to alternately tighten or loosen the hingeable connection between the bracket link  52  and the middle link  50 , locking or unlocking the position of the bracket link  52  with respect to the middle link  50 . 
     Apertures  59 D and  59 E are disposed through the bracket link  52  proximate to the heater end  76 . Bolts  82  are extended through the apertures  59 D and  59 E further through bracket  16 , and secured with nuts  84 . The bracket link  52  is thereby fixably attached to the bracket  16 . The bracket link  52  has a bend formed in the middle of the link  52 . The link  52  is shaped so that the portion of the link  52  which extends from the heater end  76  of the link  52  is parallel to the portion of the link  52  which extends from the linkage end  74  of the link  52 . Thus, the bracket link  52  does not extend in an unbroken linear fashion. The angled shape of the bracket link  52  extends the bracket  16  and the propane tank  20  further from the main linkage system  14  assembly. Thus, when the user rotates the bracket link  52  with respect to the middle link  50  about the second hinge pin  78 , the propane tank  20  will not interfere with the freedom of motion of the links  48 ,  50 ,  52 . 
     Using the three link system  14  enables the user to rotate the sportsman&#39;s furnace  10  about the coupling pin  54  as well as change the angle of the bracket  16 , propane tank  20 , and chimney  12  with respect to the flat mounting bracket  44 . The user can extend the insulated chimney  12  horizontally away from the flat mounting bracket  44  while maintaining the chimney  12  in a vertical position, by rotating the links  48 ,  50 ,  52  about their respect hinge pins  60  and  78 . The chimney  12  portion of the sportsman&#39;s furnace  10  “floats” where the user wishes the heat to be provided, while not requiring an unwieldy and cumbersome support structure that takes up a large amount of space. The furnace can quickly be pivoted away from the user to avoid interfering with the user&#39;s legs. The length of the linkage system  14  can be varied by altering the lengths of the base link  48 , middle link  50 , and bracket link  52 . In the preferred embodiment, the base link  48  is approximately 2 ¼ inches, the middle link  50  is approximately 5 ¾ inches, and the bracket link  52  is approximately 5 inches long, although a person skilled in the art would recognize that variety of link sizes may be used for the inventive furnace  10 . 
     The embodiment shown in FIG. 2 illustrates the linkage system  14  projecting upwardly with the flat mounting bracket  44  positioned below the links  48 ,  50 , and  52 . The bracket link  52  portion of the linkage system  14  is extended upwardly onto the bracket  16  before mounting. An alternate embodiment would allow the mounting bracket  44  to be mounted on a lower surface of a seat, a ceiling or other elevated object, with the links  48 ,  50 , and  52  extending below the flat mounting bracket  44  (this embodiment is discussed further with respect to FIG.  4 ). 
     The use of the cotter pin  58  and the coupling pin  54  (shown in FIG. 2) allows the user to easily disconnect the sportsman&#39;s furnace  10  from any bracket or mounting point. After disconnecting the furnace  10 , it is easily transportable from application to application and is small enough to fit inside a standard backpack (not shown). The chimney  12 , bracket  16 , burner  18  and tank  20  portion of the furnace  10  may also be separated from the linkage system  14  and supported from the floor using a fixed position stand or hung from a chain, rope, or other similar hanging device. 
     An angle bracket  85 , as displayed in FIG. 2A, may be used instead of the flat mounting bracket  44  shown in FIG.  2 . The angle bracket  85  is an L shaped bracket, and is connected to the linkage system  14  using the same method described with respect to the flat mounting bracket  44 . The angle bracket  85  has the effect of allowing the sportsman&#39;s furnace  10  to be mounted on the edge of a platform, or any other applications where a flat mounting bracket  44  would not be mountable. The angle bracket  85  is typically mounted using screws or bolts  46 A. 
     An example of a platform mounted sportsman&#39;s furnace  10  mounted using the angle bracket  85  is illustrated in FIG.  3 . The sportsman&#39;s furnace  10  is mounted to a tree stand  86  which in turn is mounted to a tree  88 . The tree stand  86  includes a platform  90  and a seat  92 . The sportsman&#39;s furnace  10  is mounted to the tree stand  86  by connecting the angle bracket  85  described with respect to FIG. 2A to the platform  90 . This mounting method is particularly useful when the platform  90  is not a solid piece of material, but instead is comprised of a grid type platform or other non-solid surface. As illustrated in FIG. 3, the linkage system  14  allows the sportsman&#39;s furnace  10  to be swung from a position distal from the seat  92  of the tree stand  86  to a position where the sportsman&#39;s furnace  10  is proximate to the seat  92 . The base link  48  turns within the angle bracket  85  to rotate the sportsman&#39;s furnace  10  in a horizontal direction. The middle link  50  is rotated about the first hinge pin  60  to adjust the vertical height versus the horizontal projection of the insulated chimney  12 . The bracket link  52  is adjusted with respect to the middle link  50  by rotating it about the second hinge pin  78  to maintain the insulated chimney  12  in a position perpendicular to the platform  90 . 
     By using the sportsman&#39;s furnace  10  in this fashion, the user of the tree stand can swing the sportsman&#39;s furnace  10  into the position proximate to the seat  92  when the user wishes to use the heater to provide warmed air. Alternatively, the user may swing the sportsman&#39;s furnace  10  to a position distal from the seat  92  when the user needs to stand or move about on the platform  90 . 
     An alternate mounting method is illustrated in FIG. 4. A pedestal seat  94  of the type which may be found in a fishing boat, is used to mount the sportsman&#39;s furnace  10 . The flat mounting bracket  44  is mounted to the underside of the pedestal seat  94 . The linkage system  14  extends downwardly from the pedestal seat  94 . Mounting the linkage system  14  extending in a downwardly fashion still allows the insulated chimney  12  and the remainder of the sportsman&#39;s furnace  10  to be mounted in an upright vertical position. This is accomplished by extending the bracket link  52  downwardly onto the bracket  16 , placing the heater end  76  of the bracket link  52  proximate to the lower edge  31  of the bracket  16 . before fixing the bracket link  52  to the bracket  16 , using nuts and bolts  95 . 
     Placing the sportsman&#39;s furnace  10  under the pedestal seat  94  in this fashion allows the user to swing the insulated chimney  12  so that it is positioned to provide heat directly underneath the user or alternatively, swing the chimney  12  away from the user. Swinging the chimney  12  away from the user&#39;s legs when the furnace  10  is not in use prevents the furnace  10  from interfering with the user&#39;s legs when he or she wishes to stand up or move about. Since the furnace  10  is mounted to the seat  94 , when the seat  94  is rotated, the furnace  10  rotates with the seat  94  and continues to provide heated air to the user. 
     The user may also wear a tent poncho  96 , which has the effect of trapping and directing heated air emitted from the sportsman&#39;s furnace  10  around the user&#39;s body. The embodiment of the tent poncho  96  shown in FIG. 4 can optionally provide a split opening (not shown) in the center back side. A magnetic closure (not shown) is used in order to secure the split opening while still allowing the poncho to hang down around both sides of the seat on the backside of the user. The magnetic closure allows more efficient trapping of heat under the garment and also will pull open with little resistance as the user stands up. The magnetic closure makes little or no sound when opened, a factor of great importance when used in deer hunting activities. Hook and loop style closures would be an alternate attachment method for the poncho used in other applications, including the pedestal seat used in fishing boats (see FIG.  4 ), or sporting events. Although the split opening can be used, a user skilled in the art will realize that it is not necessary for the poncho  96  to direct warmed air around the user. 
     Although three methods of mounting the inventive furnace  10  have been described, a person skilled in the art would realize that the furnace  10  may be mounted in a variety of environments. Additionally, any number of mounting points may be used. All variety of mounting methods gives the sportsman&#39;s furnace  10  great flexibility. 
     Utilizing the tent poncho  96  when operating the sportsman&#39;s furnace  10  allows the user to keep fresh air fed to the furnace  10  at all times. For example if the furnace  10  is used in an ice fishing shanty, the windows and door can be kept open to maintain a fresh supply of air at all times. This is imperative when using combustible fuels to avoid carbon monoxide poisoning. The fresh air supply prevents incomplete burning or re-burning of oxygen depleted air both of which create carbon monoxide during the combustion of petroleum based products. In addition, use of the tent poncho  96  allows efficient trapping of the low heat output by the low BTU burner  34  while the user&#39;s face is exposed to fresh air. The overall concept of a low BTU output sportsman&#39;s furnace  10  combined with the tent poncho  96  shelter allows efficient use of a mechanical heat source outside of an enclosed area, thus eliminating risk of carbon monoxide poisoning. Even without the poncho  96 , however, the use of the low BTU burner  34  and the open bottom of the chimney  12  prevents carbon monoxide buildup by allowing enough oxygen to be supplied to the burner  34 . 
     Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.