Abstract:
A collapsible stove includes an expandable combustion chamber formed from nested annular rings that can collapse to about the height of a single ring and expand into a combustion chamber for burning combustible materials. Ventilation holes at the bottom of the combustion chamber provide airflow into the combustion chamber. The combustion chamber is frustoconical and narrows at the top which increases air flow into the combustion chamber via the Venturi effect. Fuel can be added and ignited in the combustion chamber and cookware containing food can be placed onto an associated top plate suspending the combustion chamber. The collapsible stove can include rotatable legs. To use the stove, the rotatable legs can be opened, allowing the nested annular rings to telescope and expand to form the combustion chamber. For carrying and storage, the nested annular rings can be collapsed and a rotatable leg can secure the rings in the collapsed configuration.

Description:
REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Patent Application No. 62/295,786 filed Feb. 16, 2016 and titled “Portable Cooking Stove”, which is herein incorporated by reference. 
     
    
     TECHNICAL FIELD 
       [0002]    This application relates generally to a stove having a collapsible combustion chamber. The application relates more particularly to a lightweight portable cooking stove having nested tapered rings that are configured to extend to form a combustion chamber when suspended from the cooking surface. 
       BACKGROUND 
       [0003]    People participate in outdoor recreational activities such as camping. Campers often build fires for warmth and for cooking. A cooking stove can be used to direct and concentrate flames and heat onto cooking containers such as pots, pans, or plates. Current cooking stoves have disadvantages. Stoves that rely on prepackaged fuel, such as propane or liquid fuel require the user to carry a supply of fuel in order for the stove to be used. Often, these supplies can be heavy and bulky. Once the supply of fuel is exhausted, then the stove is no longer usable. Also, stoves that use wood as fuel are often bulky because they have combustion chambers that need to be large enough to hold a useful amount of wood. 
       SUMMARY 
       [0004]    In accordance with an example embodiment of the subject application, a collapsible stove includes a combustion chamber and a top plate displaced over the combustion chamber. The combustion chamber includes a number of tapered annular rings that are configured to telescope into the combustion chamber when the stove is opened into the open configuration. The tapered annular rings are configured to collapse into a nested configuration when the stove is closed into the closed configuration. The top plate includes a aperture that opens to the combustion chamber and includes stand offs to support a cooking container such as a pot, pan, or plate over the aperture to the combustion chamber. One of the tapered annular rings, for example the bottom ring, can include a number of ventilation holes. The combustion chamber when opened is substantially frustoconical which, during combustion, enables the Venturi effect to increase air flow to combustible materials placed into the combustion chamber and burned. The combustion chamber can be secured to, and hang from or be suspended from, the top plate. The combustion chamber can be suspended such that there is an air gap between the bottom plate of the combustion chamber and the surface upon which the the stove is placed. The combustion chamber can be permanently or removably secured to the top plate. A plurality of rotatable leg supports and suspend the stove and combustion chamber in an elevated position when the stove and the legs are opened. When collapsed, one or both of the legs can secure the tapered annular rings in the nested configuration, for example by abutting a portion of a leg against the bottom plate. One or both rotatable legs can secure the stove in the collapsed configuration, for example by pressing on the other leg or frame. The top cover can include an opening that has a wider diameter than the combustion chamber but a smaller diameter than the top plate, such that the top plate can rest upon a least a portion of the top cover and the combustion chamber can be suspended in the opening. The stove can include a frame to which the top plate is secured, with the top cover sandwiched between the frame and top plate. One or more connectors or pegs or a combination thereof can be configured to pass into holes in the other members and allow the top plate to be secured to the frame. The pegs can be fixed to one of the members. The rotatable legs can be coupled to the frame in such a way as to allow at least partial rotation. When collapsed the nested tapered annular rings collapse to have a height that is approximately the height of the frame and top plate, so as to facilitate storage and carrying. Similarly, the legs can collapse into the frame so that the entire stove is approximately the height between the bottom of the frame and the top of the top plate. 
         [0005]    In accordance with an example embodiment of the subject application, a collapsible stove includes a frustoconical combustion chamber having a number of tapered annular rings that can telescope and expand into the fully open configuration from a nested configuration. When the rings are in the nested configuration, the combined height of the nested rings is approximately the height of a single ring. The combustion chamber has a wider diameter at the bottom than the top. The shape of the combustion chamber can facilitate the flow of air into the combustion chamber via the Venturi effect. The stove can include two or more rotatable legs. When rotated closed, one or more of the legs can secure the tapered annular rings in the collapsed nested configuration. When rotated opened, the legs can suspend the combustion chamber, for example over the ground. A top plate can hold cookware above the combustion chamber and an associated top cover can hold the top plate and suspend the combustion chamber above the ground. The combustion chamber can be secured to the top plate either removably or permanently. 
         [0006]    In accordance with an example embodiment of the subject application, a method includes opening at least one rotatable leg of a collapsible stove to release a number of nested tapered rings. When released, the tapered rings expand, for example by telescoping, into a suspended frustoconical combustion chamber. The method can include placing combustible fuel into the combustion chamber and igniting the fuel to generate heat above a tape plate associated with the stove. By placing cookware containing a food item onto the top plate, the food item can be cooked. After use, the combustion chamber can be emptied of residual ash and unburned fuel, for example by inverting the stove and collapsing the combustion chamber into a nested configuration. When in the nested configuration the tapered rings have the height of approximately a single one of the tapered rings. By closing a rotatable leg, the rings can be secured in a nested, collapsed configuration. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    Various embodiments will become better understood with regard to the following description, appended claims and accompanying drawings wherein: 
           [0008]      FIG. 1A  is a section view of a collapsible stove in an opened configuration according to an embodiment of the disclosure; 
           [0009]      FIG. 1B  is a section view of the collapsible stove of  FIG. 1A  in a partially collapsed configuration according to an embodiment of the disclosure; 
           [0010]      FIG. 1C  is a section view of the collapsible stove of  FIG. 1B  in a fully collapsed configuration according to an embodiment of the disclosure; 
           [0011]      FIG. 2A  is a side view of a collapsible stove in an opened configuration according to an embodiment of the disclosure; 
           [0012]      FIG. 2B  is a side view of the collapsible stove of  FIG. 2A  in a partially collapsed configuration according to an embodiment of the disclosure; 
           [0013]      FIG. 2C  is a side view of the collapsible stove of  FIG. 2B  in a fully collapsed configuration according to an embodiment of the disclosure; 
           [0014]      FIG. 3A  is a top view of a collapsible stove according to an embodiment of the disclosure; 
           [0015]      FIG. 3B  is a bottom view of the collapsible stove of  FIG. 3A  in a collapsed configuration according to an embodiment of the disclosure; 
           [0016]      FIG. 4A  is a top perspective view of a collapsible stove in an opened configuration according to an embodiment of the disclosure; 
           [0017]      FIG. 4B  is a top perspective view of the collapsible stove of  FIG. 4A  in a partially collapsed configuration according to an embodiment of the disclosure; and 
           [0018]      FIG. 4C  is a top perspective view of the collapsible stove of  FIG. 4B  in a fully collapsed configuration according to an embodiment of the disclosure. 
           [0019]      FIG. 5A  is a bottom perspective view of a collapsible stove in an opened configuration according to an embodiment of the disclosure; 
           [0020]      FIG. 5B  is a bottom perspective view of the collapsible stove of  FIG. 5A  in a partially collapsed configuration according to an embodiment of the disclosure; and 
           [0021]      FIG. 5C  is a bottom perspective view of the collapsible stove of  FIG. 5B  in a fully collapsed configuration according to an embodiment of the disclosure. 
           [0022]      FIG. 6A  is a top exploded view of a portion of the collapsible stove according to an embodiment of the disclosure. 
           [0023]      FIG. 6B  is a bottom exploded view of a portion of the collapsible stove according to an embodiment of the disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    The systems and methods disclosed herein are described in detail by way of examples and with reference to the figures. It will be appreciated that modifications to disclosed and described examples, arrangements, configurations, components, elements, apparatuses, devices methods, systems, etc. can suitably be made and may be desired for a specific application. In this disclosure, any identification of specific techniques, arrangements, etc. are either related to a specific example presented or are merely a general description of such a technique, arrangement, etc. Identifications of specific details or examples are not intended to be, and should not be, construed as mandatory or limiting unless specifically designated as such. 
         [0025]    Referring to  FIGS. 1A, 1B, and 1C , illustrated is an example embodiment of a collapsible stove  100 .  FIG. 1A  illustrates a section view of the collapsible stove  100  in the fully open configuration.  FIG. 1B  illustrates a section view the collapsible stove  100  in a partially open configuration.  FIG. 1C  illustrates a section view the collapsible stove  100  in the fully collapsed configuration. The collapsible stove  100  comprises a first leg  102 , a second leg  104 , a frame  106 , a top cover  108 , a top plate  110 , and a collapsible combustion chamber  114 . 
         [0026]    The legs  102 ,  104  can attach to a frame  106  via a rotatable pivot point, allowing the legs  102 ,  104  to be opened in order to suspend the frame  106 , surface  108 , top plate  110 , and combustion chamber  114  above the ground. In a configuration, each of the legs  102 ,  104  can rotate more than ninety degrees to provide stable support of the frame  106 . In a configuration, the legs  102 ,  104  can be configured to stop rotating once part of the legs  102 ,  104  abuts part of the frame  106 . In another configuration, the legs  102 ,  104  and frame  106  can be configured to increase friction between members as the legs  102 ,  104  are rotated into the open position. In another configuration, detents such as protrusions or indents in the frame  106  and/or legs  102 ,  104  can limit rotation or secure the legs  102 ,  104  in the open position as would be understood in the art. The legs  102 ,  104  can be secured similarly in the closed position. In a configuration, clevis pins or other types of removable connectors can be used to secure the legs  102 ,  104  to the frame  106 , while facilitating easy removal for cleaning or replacement. In other embodiments, fixed legs, telescoping legs, or multi-part legs can be used as would be understood in the art. 
         [0027]    Referring also to  FIGS. 6A and 6B , the top cover  108  and top plate  110  can be secured to the frame  106 . For example, the top cover  108  can be positioned on the frame  106  and the top plate  110  positioned on top of the top cover  108 . The top cover  108 , top plate  110 , and frame  106  can then be secured together, for example using screws, c-clips, bayonet mounts, and other connectors. For example, as illustrated in  FIG. 6B , screws  608  pass through thru holes  610  in the frame  106  and thru holes (not shown) in the top cover  108  and into threaded screw holes  612  in the top plate  110 . For ease of assembly, a combination of pegs and holes can be used in combination with connectors. One or more pegs can be fixably attached to one of the top plate  110 , the frame  106 , or the top cover  108  and be configured to enter into holes in the other parts. The pegs and holes can align and hold the top plate  110 , frame  106 , and top cover  108  in place and also align other holes for the connectors. For example, as illustrated in  FIG. 6A , pegs  602  in the top plate  110  pass through thru holes  604  in the top cover  108  and into holes  606  in the frame  106 . One or more connectors can then be used to secure the parts together as described above and as illustrated in  FIG. 6B . Easily removable connectors, such as bayonet mounts, can be used in combination with pegs and holes to make it easier for the user to take the pieces apart for maintenance and cleaning, especially in the field where a user may not have tools available or easily accessible. 
         [0028]    In different embodiments, the top cover  108 , top plate  110 , and frame  106  can be individual pieces or can be combined into one or more pieces as would be understood in the art. In the embodiment presented in the associated figures, the top cover  108 , top plate  110 , and frame  106  are individual pieces. This embodiment advantageously takes advantage of different materials to reduce cost, reduce weight, add strength, improve durability, and improve temperature control. For example, the top cover  108 , frame  106 , and legs  102 ,  104  can be constructed of stamped aluminum, and can include ridges and other structural features, for example as illustrated in  FIGS. 4A-4C , to improve stiffness without substantially adding weight. Keeping the top cover  108  separate from the top plate  110  advantageously reduces substantial heat transfer from the top plate  110  and the associated combustion chamber  114  to the top cover  108 , thereby reducing the likelihood of accidental burns to users during use and providing a cooler surface for placement of utensils or food preparation activities such as cutting. The combustion chamber  114  can be constructed of a suitable lightweight high temperature material such as stainless steel. The top plate  110  and stand off  112  can be constructed of cast aluminum that provides both durability and ample heat conduction to an associated pot, pan, or plate. 
         [0029]    The top plate  110  can include a plurality of stand offs  112 . The stand offs  112  can elevate a pot, pan, or plate that is placed on the stand offs  112 . The stand offs  112  allow an air gap between top plate  110  and the pot, pan, or plate for exhaust gasses to escape from the combustion chamber  114 . In a configuration, the stand offs  112  can be integrated into the top plate  110 , for example as a single cast part. In another configuration, the stand offs  112  can be removable or configured to fold down or rotate into the combustion chamber  114  to further reduce space or to allow a pot or pan to be placed over the combustion chamber  114  to help extinguish any burning material therein. 
         [0030]    The combustion chamber  114  can be secured to the top plate  110 , for example using a bayonet mount, a screw thread, individual screws, or permanent affixation such as welding. The combustion chamber  114  is comprised of a plurality of concentric rings  116 , for example tapered annular or cylindrical rings as shown. The rings  116  are configured such that a lower portion of each ring  116  has a larger diameter than an upper portion of an adjacent ring  116 . In this way, when the rings  116  are allowed to expand, for example by the action of gravity, each ring  116  will hold the ring  116  below in place to form a substantially sealed combustion chamber  114  that has an approximately frustoconical shape. The frustoconical shape of the combustion chamber  114  not only concentrates heat at the top plate  110 , but also advantageously takes advantage of the Venturi effect to draw ample air into the combustion chamber  114  to increase combustion and heat production. One or more rings  116  can include a plurality of ventilation holes  120  for drawing air into the combustion chamber  114 . The ventilation holes  120  can be configured to allow air to enter the combustion chamber  114 , or allow ash to be removed, while keeping burning material and hot coals safely inside of the combustion chamber  114 . The ventilation holes  120  can be approximately triangular in shape as illustrated. A bottom plate  122  can be secured to the lowest ring  116  to retain burning material, for example using screws, threads, or other means of securing as described above. The bottom plate  118  also can include ventilation holes  118 . The bottom plate  122  can have a larger diameter than the diameter of any ring  116  and advantageously assist in securing the rings  116  when the combustion chamber  114 ′ is in the collapsed configuration. 
         [0031]    The combustion chamber  114 ′ can be collapsed into a collapsed configuration as shown in  FIG. 1B . When collapsed the rings  116  nest inside one another. In this way, the combustion chamber  114 ′ reduces to a height approximately equal to that of the rest of the collapsible stove  100 . The first leg  102  can be rotated from the open position to the closed position as shown in  FIG. 1C . The second leg  104  can be similarly closed. One or both of the legs  102 ,  104  can secured the combustion chamber  114 ′ in the collapsed configuration, for example by having a portion of a leg  102 ,  104  overlap part of the combustion chamber  114 ′. Advantageously, the combustion chamber  114 ′ will not open or expand until one or both of the legs  102 ,  104  are opened. 
         [0032]    Advantageously, the tapered cylindrical sections or rings  116  of the combustion chamber  114 ′ can be nested into a compact configuration for ease of storage and carrying of the collapsible stove  100 . A user can collapse the sections into the compact configuration by hand or by turning the stove upside down and allowing the rings  116  to collapse by the action of gravity. This might be performed, for example, when emptying the combustion chamber of ash or leftover unburned fuel prior to storage. Once the combustion chamber  114 ′ is collapsed, the user can close the legs of the collapsible stove  100  to secure the collapsed rings  116  in place for storage and carrying. In an embodiment, the tapered cylindrical sections or rings  116  of the combustion chamber  114  can include structures for locking the rings in the open configuration. For example, each ring can include screw threads or bayonet mounts for locking each ring with an adjacent ring. 
         [0033]      FIGS. 2A, 2B, and 2C  illustrate side views of the collapsible stove of  FIGS. 1A, 1B, and 1C .  FIGS. 3A and 3B  illustrate top and bottom views of the collapsible stove  100  respectively. In the top view of  FIG. 3A , the top cover  108  includes ridges  302  that can add structural support and stiffness to the top cover  108 , or provide a distinctive decorative look. For example, the ridges  302  as illustrated form a hexagonal pattern. The choice of a hexagonal pattern, or any other desired pattern, can be selected for aesthetic or design reasons. However, any suitable shape of ridge  302  can be used to increase structural strength, and the ridge  302  can be configured to add strength while minimizing the amount of additional material and weight. The pattern of the ridges  302  can be partially carried to the top plate  110  as shown for decorative or design reasons. 
         [0034]    In the bottom view of  FIG. 3B , the first leg  102  is illustrated securing the combustion chamber in the collapsed configuration by overlapping a portion of the first leg  102  against the bottom plate  122 . The ventilation holes  118  of the bottom plate  122  can be configured to allow ample air flow while retaining hot coals and allowing spent ash to be emptied. The ventilation holes  118  can be reinforced for added strength and heat resistance. The second leg  104  is illustrated as having a portion that fits between the frame  106  and first leg  102 . By appropriately sizing portions of the first leg  102 , the second leg  104 , and the frame  106 , the legs  102 ,  104  can be secured against one another or the frame  106  by friction, thereby facilitating the carrying and storing of the collapsible stove  100  in the collapsed configuration. In various configurations, indentations, detents, straps, springs, or other means of securing can be used in addition to, or instead of, friction as would be understood in the art. 
         [0035]      FIGS. 4A, 4B, and 4C  similarly illustrate top perspective views of the collapsible stove of  FIGS. 1A, 1B, and 1C .  FIGS. 5A, 5B, and 5C  similarly illustrate bottom perspective views of the collapsible stove of  FIGS. 1A, 1B, and 1C . 
         [0036]    While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the inventions. Indeed, the novel embodiments described herein may be embodied in a variety of other forms; furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the spirit and scope of the inventions.