Abstract:
An initiator with fuse device for an automatic self-contained fire suppressor and method are provided herein. Stovetop fires are a well-known residential and commercial hazard. An initiator with fuse device provides a reliable activation of an automatic stovetop fire suppressor. A device and method which provides a secure and robust attachment of an initiator to a fire suppressor, while reducing required component parts, manufacturing time, and labor, is provided herein. An initiator cup with integral cylindrical extension affords a thermoform attachment of the cup to the fire suppressor container while providing a secure mechanical attachment of the fuse to the initiator cup.

Description:
FIELD OF THE INVENTION 
     The present invention relates to a device and method of fire suppression, and more particularly to an initiator device and method thereof for an automatic stovetop fire suppressor. 
     BACKGROUND OF THE INVENTION 
     Stovetop fires are a well-known residential and commercial hazard. An unattended stovetop fire, for example a grease fire, can cause damage to nearby appliances and cabinets. Worse, stovetop fires can lead to structural damage or injury. Because the propensity for stovetop fires is so pervasive, an efficient means of automatic fire suppression is desired. Even if a stovetop fire is attended, an automatic extinguishing method may be more effective, safe, and expedient compared to manual means. 
     A number of conventional automatic stovetop fire extinguishers, which mount near a stovetop surface, are available. These include: U.S. Pat. No. 6,276,461 to Stager; U.S. Pat. No. 6,105,677 to Stager; U.S. Pat. No. 5,899,278 to Mikulec; U.S. Pat. No. 7,472,758 to Stevens and Weintraub; U.S. Pat. No. 7,610,966 to Weintraub et al; U.S. Pat. No. 5,518,075 to Williams; and U.S. Pat. No. 3,884,307 to Williams. The array of conventional fire suppression systems vary from activation by melting of a fusible pin (Stager &#39;461), to melting a solder fusible plug (Stager &#39;677), to burning of a fuse (Williams &#39;307, Stevens &#39;758), or to activating via a glass bulb fuse mechanism (Mikulec). 
     Conventional fire extinguishers, STOVETOP FIRESTOP® fire suppressors (Williams-Pyro, Inc., Fort Worth, Tex., USA), which are particularly well suited to a stovetop environment, include a container of an extinguishing or fire suppressing agent mounted to a vent hood above the stovetop and activated by a fuse. An example of such an extinguisher is shown in  FIG. 1A .  FIG. 1A  is a partial cross-sectional view of a conventional fire suppressor, revealing the initiator  101  within the container  23  of the fire suppressor  100 . Container  23  has a top wall  23 B and a side wall  23 C, while the bottom of the container is a lid  27 , which comprises a lip  23 A. Shown exiting from the lid  27  is fuse  61  which feeds into an initiator  101  in the fire suppressor  100 . A fire on the stovetop ignites the fuse  61 , which in turn detonates an initiator  101 . The igniter opens the bottom  27  of the container  23 , thereby allowing the disbursement of the extinguishing agent  29  onto the fire and the stovetop. The conventional fuse and initiator assembly is effective at automatically activating a fire suppressor under a stovetop fire condition. Still referring to  FIG. 1  A, also shown on an outer side of lid  27  is a terminal  93 . A magnet  31  and magnet housing  33  provide a vent hood mount for the conventional stovetop fire suppressor. 
     A conventional initiator, which may be found in a conventional fire-suppressor such as that shown in  FIG. 1A , is shown in greater detail in  FIG. 1B  and is described below with reference to  FIG. 1B . The conventional fuse and initiator assembly is effective at activating a fire suppressor in the presence of a stovetop fire. Manufacture and assembly of a conventional fuse and initiator assembly is described below with reference to  FIG. 2 . As in many conventional manufacturing processes and as with many products, it would be desirable to improve the efficiency of the manufacturing process of the initiator and to improve the initiator device if possible. It may also be desirable to have a fuse that is activated only by a flame and not by heat or electrical charge. 
     SUMMARY OF THE INVENTION 
     The present invention addresses some of the issues presented above by providing a new initiator cup in an automatic stovetop fire suppressor. Embodiments of the present invention may have any of the aspects below. 
     One aspect of the present invention is to provide an efficient flame activation apparatus for a stovetop fire suppressor. 
     Another aspect of the present invention is to improve the manufacturing efficiency of an initiator and to assemble a stovetop fire extinguisher 
     Another aspect of the present invention is to reduce the number of processing steps to manufacture an initiator and to assemble a stovetop fire extinguisher. 
     Another aspect of the present invention is to create an initiator with fewer parts than conventional initiators. 
     Another aspect of the present invention is to create an initiator at a decreased cost. 
     Another aspect of the present invention is to decrease assembly process time to create an initiator for a fire suppressor. 
     Yet another aspect of the present invention is to decrease assembly labor to build an initiator. 
     Yet another aspect of the present invention is to provide improved fuse retention in an initiator for an automated stovetop fire extinguisher. 
     Yet another aspect of the present invention is to provide improved fuse retention in an initiator for an automated stovetop fire suppressor using a rough fuse outer surface. 
     Yet another aspect of the present invention is to provide improved fuse retention in an initiator for an automated stovetop fire suppressor using a smaller inner diameter of the fuse passage in the cup as compared to an outer diameter of the fuse. 
     Yet another aspect of the present invention is to mechanically seal the fire extinguishing container about the fuse. 
     Yet another aspect of the present invention is that the attaching mechanism securing the initiator cup to the container lid is integrated to the cup itself. 
     Those skilled in the art will further appreciate the above-noted features and advantages of the invention together with other important aspects thereof upon reading the detailed description that follows in conjunction with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
       For more complete understanding of the features and advantages of the present invention, reference is now made to the detailed description of the invention along with the accompanying figures, wherein: 
         FIG. 1A  is a partial cross-sectional view of a conventional fire suppressor, revealing the initiator within the fire suppression container and  FIG. 1B  shows a cross section of the conventional initiator with fuse in greater detail; 
         FIG. 2  shows a conventional method of making an initiator for an automatic stovetop fire extinguisher container; 
         FIG. 3A  shows a cross section of an initiator cup and fire suppression container lid, in accordance with an exemplary embodiment of the present invention; 
         FIG. 3B  shows a cross section of an initiator cup with fuse attached to a fire suppression container lid, in accordance with an exemplary embodiment of the present invention; 
         FIG. 4  shows an exemplary method of making an initiator with fuse for an automatic stovetop fire suppressor container, in accordance with an exemplary embodiment of the present invention; and 
         FIG. 5  shows a partial base wall and cylindrical extension of an initiator, in accordance with an exemplary embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The invention, as defined by the claims, may be better understood by reference to the following detailed description. The description is meant to be read with reference to the figures contained herein. This detailed description relates to examples of the claimed subject matter for illustrative purposes, and is in no way meant to limit the scope of the invention. The specific aspects and embodiments discussed herein are illustrative of ways to make and use the invention, and are not intended to limit the scope of the invention. Same reference numbers across figures refer to like elements for ease of reference. Reference numbers may also be unique to a respective figure or embodiment. 
     Briefly,  FIG. 1A  is a partial cross-sectional view of a conventional fire suppressor, revealing an initiator within the fire suppression container and  FIG. 1B  shows a cross section of a conventional initiator with fuse in greater detail. Referring to  FIG. 1A , a fire suppressor  100  has a container  23  which has a top wall  23 B, side wall  23 C and a bottom lid  27 . Housed within the container are extinguishing, fire suppressing, matter  29  and an initiator  101 . A fuse  61  feeds into the initiator. Surrounding the fuse  61  is a terminal  93 . Turning to  FIG. 1B , the initiator  101  has a cup  103 , a cap  115 , and explosive or explosive substitute material  121  housed in the cup  103 . The cup  103  a side wall  107  and a center hole  109  through its bottom wall  105 . The cup bottom wall  105  sits directly atop fiber washer  140 . The fiber washer is not shown in  FIG. 1A . Referring again to  FIG. 1B , the terminal  93  comprises a lower shield end  94  and a top rivet end  97 . The terminal  93  secures the cup  103  to the lid  27 . The cap  115  is secured to the top  111  of the side wall  107 . When assembled the fuse  61  extends out an outer side  22  of the lid  27  while the felt washer  140  is sandwiched between the bottom wall  105  of the cup  103  and the inner side  21  of the lid  27 . The terminal  93  extends from an inner side of the cup  103  at its rivet end  97  through the cup hole  109 , the washer  140  and a lid hole  99 , which are all aligned along a device center  1 - 35 . Fuse  61  has a surface  1 - 10 - s  and a diameter  1 - 10 - d  and will be further described below relative to  FIGS. 3A and 3B . 
       FIG. 2  shows a conventional method of making an initiator for an automatic stovetop fire extinguisher container. Referring to  FIG. 2 , position an initiator cup on the inner side of the container lid  265 . Place a felt washer between the cup and the lid  270 . Align the respective centered openings of the bottom wall of the cup, the washer, and the lid  275 . Insert the rivet end of the terminal from outside the lid through the three aligned openings  280 . Rivet the terminal in place, coupling the terminal and cup to the lid  285 . Press fit a fuse into the terminal opening to extend from within the cup to an outside of the lid  290 . Apply lacquer at terminal opening and fuse interface, sealing the fire suppressor container and securing the fuse in place  295 . The cup may then be loaded with a predetermined quantity of combustible material  121 . The combustible material could be loaded into the cup  103  before the fuse  61  is inserted. Securing of cap  115  to the top  111  of the cup  103  completes a conventional process. 
       FIG. 3A  shows a cross section of an initiator cup and a fire suppression container lid, in accordance with an exemplary embodiment of the present invention. Container lid  20  has an inner side  21  and an outer side  22 . An initiator cup  3 - 34  has a side wall  3 - 34 - 1  and a base wall  3 - 34 - 2 . The cup  3 - 34  has a centered  3 - 35  hole in a base wall  3 - 34 - 2 . A cylindrical extension, or extended base,  3 - 23  is integrated with the base  3 - 34 - 2  and has an inner diameter of  3 - 13 - d . The outer diameter  3 - 13 -D of the cylindrical extension fits into a centered  3 - 35  hole in the lid  20 , where the centered lid hole has nearly the same  3 - 13 -D diameter as that of outer diameter of the cylindrical extension  3 - 23 . In  FIG. 3A , the cylindrical extension  3 - 23  is shown in its extended form  3 - 13 . 
       FIG. 3B  shows a cross section of an initiator cup  3 - 34  with fuse  3 - 10  attached to a fire suppression container lid  20 , in accordance with an exemplary embodiment of the present invention. The cup  3 - 34 , cylindrical extension  3 - 23 , and lid  20  retain centered  3 - 35  holes. The cup  3 - 34  is shown with its side wall  3 - 34 - 1 . The cup&#39;s base  3 - 34 - 2  is juxtaposition an inner side  21  of the lid  20 . The cylindrical extension  3 - 23  has been formed into its attachment form  3 - 13 -A. An outer edge of attached cylindrical extension  3 - 13 -A now extends past the diameter of the lid  20  hole, where lid hole diameter is approximately that of the outer cylindrical extension  3 - 10 -D, shown in  FIG. 3A . Referring again to  FIG. 3B , in accordance with an exemplary embodiment, fuse  3 - 10  has a rough surface  3 - 10 - s  and an outer diameter  3 - 10 - fd . In accordance with exemplary embodiments of the present invention, the initiator cup  3 - 34  with its cylindrical extension  3 - 23  is one injection molded piece. 
       FIG. 4  shows an exemplary method of making an initiator with fuse for an automatic stovetop fire suppressor container, in accordance with an exemplary embodiment of the present invention. Referring to  FIG. 4 , injection mold initiator cup with its cylindrical base/extension  405 . Place cup on a lower nest in an ultra-sonic welder with the extended base/cylindrical extension facing up  410 . Position the container lid above the cup with the inside of the lid facing down  412 . Align the centered hole in the lid with the outside diameter of the cylindrical extension  414 . Lower the lid over the extended base, cylindrical extension, of the cup  422 . Acquire fuse of desired length  424 . Insert fuse from outside extended base into cup  426 . Activate ultra-sonic welder and form material of extended base over outer lid surface radially beyond center holes, extending base extension radially beyond lid outer diameter  430 . Continue welding to firmly attach cup to lid  433 . Extrude plastic around fuse  434 . 
       FIG. 5  shows a partial base wall  3 - 34 - 2  and cylindrical extension  3 - 24  of an initiator, in accordance with an exemplary embodiment of the present invention. The base wall  3 - 34 - 2  may have a thickness  3 - 34 - 2 - t  of between 0.03 and 0.06 inches. The cylindrical extension  3 - 24 , or extended base  3 - 24 , may have the same thickness  3 - 34 - 2 - t  as the base wall  3 - 34 - 2  of the cup or may have a different thickness. The cylindrical extension thickness  3 - 13 - t  may be between 0.03 and 0.06 inches. The cylindrical extension  3 - 24 , shown in its extended form  3 - 13  may have a height between 0.10 and 0.20 inches. All dimensions are exemplary and any given cup embodiment, in accordance with the present invention, may have any or all of the exemplary dimensions. Still referring to  FIG. 5 , the extended base  3 - 24 , cylindrical extension  3 - 24 , may have an inner diameter  3 - 13 - d  of between 0.10 and 0.12 inches and/or an outer diameter  3 - 13 -OD of between 0.16 and 0.24 inches in its extended form  3 - 13 , in accordance with an exemplary embodiment of the present invention. In accordance with an exemplary embodiment of the present invention, the angle  3 - 14  between the integral base wall  3 - 34 - 2  and the cylindrical extension  3 - 23  in extended form  3 - 13  is ninety degrees. In accordance with an exemplary embodiment, the initiator base wall  3 - 34 - 2 - t ,  FIG. 5 , and the cylindrical extension  3 - 13 - t ,  FIG. 5  wall thickness may be the same and the initiator side wall  3 - 34 - 1 ,  FIG. 3A  may also have the same thickness. In alternate embodiments, any two of base wall, side wall, and cylindrical extension are equal. In still another exemplary embodiment, no two have the same thickness. 
     In accordance with an exemplary embodiment of the present invention, the cup and cylindrical extension are integral and may be made using a thermoform process, such as injection molding. During attachment of the initiator cup  3 - 34  to the container lid  20 , the cylindrical extension  3 - 24  may be formed  3 - 13 -A to a dimension larger than the diameter of the lid hole, in accordance with exemplary embodiments of the present invention, as shown in  FIG. 3B . This process can provide a stable attachment of the cup  3 - 34  to the lid  20 . Further, this thermoform process may seal the holes of the cup and container, preventing fire suppressant powder from leaking from the container. In turn, the fiber washer  140  of the conventional initiator, as shown in  FIG. 1B  for example, may be eliminated and is eliminated in accordance with an exemplary embodiment of the present invention. In accordance with embodiments of the present invention, the terminal  93  with its shield  94  and rivet  97 , also shown in  FIG. 1B , is omitted. This elimination of fiber washer and terminal reduces the parts needed to form an initiator. 
     The present invention provides a novel method of attaching an initiator cup to a fire suppressor container. Exemplary embodiments of the present invention incorporate a novel approach to securing the fuse to the initiator. The effective fuse retention, in accordance with exemplary embodiments of the present invention does not require the conventional application of lacquer to secure the fuse and seal the container  295 , described for example in relation to  FIG. 2 . The elimination of the need for lacquer and its application may further improve the manufacturing process by, for example, reducing costs, manufacturing time, and labor. The mechanical sealing of the container and securing of the fuse with the thermoforming of the cylindrical extension into attachment form may improve long term fuse retention in the initiator and the associated fire suppressor. The mechanical thermoform attachment may be more robust than the terminal and lacquer container closure and fuse attachment method. 
     In accordance with the present invention, the fuse can be inserted into the cylindrical extension and the initiator-fuse assembly can be thermoformed to firmly attach the cup to the lid and secure the fuse to the cup as shown in  FIG. 3B . Thermoforming the cylindrical extension will extrude plastic material around the fuse. Such method for may provide a more robust securing of the fuse to the initiator and may provide improved fuse retention over conventional methods. Further, the plastic extrusion can contribute to tamper-proofing the stovetop fire suppressor. 
     Embodiments of the present invention may include a fuse diameter larger than in internal cylindrical extension diameter. This may provide a twofold advantage, yielding an increase in exposed area to a stovetop flame contributing to securing of the fuse to the cup. Use of a rough surfaced fuse, in accordance with an exemplary embodiment of the present invention may also yield a more robust attachment of the fuse to the initiator cup. For example, an inadvertent tug on the fuse may have no effect on the activation integrity of the device due to an improved mechanical adhesion, or grip, of the cup on the fuse created by the rough or gritty fuse outer surface. In accordance with an exemplary embodiment of the present invention, the fuse employed is lacking a metallic member. This non-metallic fuse will provide flame activation while eliminating heat or electric charge activation of the fire suppressor. 
     While specific alternatives to steps of the invention have been described herein, additional alternatives not specifically disclosed but known in the art are intended to fall within the scope of the invention. Thus, it is understood that other applications of the present invention will be apparent to those skilled in the art upon reading the described embodiments and after consideration of the appended drawings.