Patent Publication Number: US-5893711-A

Title: Space heater with plastic fuel tank

Description:
This invention relates to a space heater and particularly a portable space heater in which the fuel of the space heater is contained within a plastic tank. More particularly, this invention relates to such a space heater having a plastic fuel tank in combination with a unique structure for supporting the heater unit above the plastic tank on the frame of the portable heater so as to substantially eliminate any detrimental stress being exerted on the plastic tank by the weight of the heater unit. 
     BACKGROUND OF THE INVENTION 
     Portable heaters of the type that included a metal tank over which is mounted a heater unit generally of a cylindrical shape have existed for a long time and have been the subject of much development efforts. Examples of this type of portable heater is disclosed in U.S. Pat. Nos. 4,081,238, 4,089,642, and 4,340,362. To our knowledge, this type of portable heater has always included a fuel tank constructed of metal such as steel. Such tanks have always been mounted on frames constructed in many instances of tubular piping and the frame has been mounted on wheels making the heater portable. 
     Further, to our knowledge, generally the heater unit which included a combustion chamber with a motor driven fan mounted within a cowling have been mounted directly on the top of the metal tank. As previously stated, efforts have been made to develop better and less costly portable heaters of this type with many different improvements having been made over the years. 
     The present invention is an improvement of this type of portable heater. Such improvement making the heater less costly to manufacture and also much lighter in weight which is important in portable heaters of this type. 
     SUMMARY OF THE INVENTION 
     The present invention involves the concept of utilizing a plastic tank in lieu of the metal tanks which to our knowledge have been used throughout the years although plastic tanks have been available for many different uses, particularly for carrying fuel or replenishing the apparatus which utilizes such fuel. 
     This invention also involves a unique concept for supporting the heater unit i.e., the combustion chamber, the fan and its motor, and all of the accessories necessary for operating the heater. This unique support for the heater unit includes a support structure supported on the same frame on which the tank is mounted. This support structure supports the cradle for the heater unit so as to substantially eliminate any stress being exerted on the plastic tank by the weight of the heater unit. This structure is in contrast to the prior art portable heaters of this type in which the heater unit is mounted on a cradle which is supported directly on the top surface of the metal tank. 
     More specifically, the cradle which includes a support surface on which the heater unit is supported is supported by legs extending downwardly from the cradle and supported directly on the portable frame. The support members which extend downwardly from the cradle each include a part extending radially outwardly of at least portions of the sides of the tank and over the tank to the frame which includes two longitudinally extending support members on each side of the tank. 
     Our invention includes at least two embodiments. One embodiment includes a cradle mounted on two downwardly extending legs which at the extreme lower ends include a flange. The legs extend downwardly beyond at least a portion of the tank and the flanges are mounted on the same frame as the tank is mounted. The legs of this first embodiment are one-piece supporting the cradle between the two legs. 
     Another embodiment includes two parts comprising an inverted U-shaped member having a bight portion extending laterally across and over the tank and a cradle supported on the bight portion. In this embodiment the bight portion is supported by legs extending from the bight portion and supported on the frame. The other piece comprises a cradle supported on legs mounted on the bight portion. The legs formed on the inverted U-shaped member include flanges extending away from the sides of the tank and supported on the same frame as the tank. In other words, the downwardly supporting members that support the cradle includes two spaced legs mounted on top of the bight portion of the inverted U-shaped member and leg extensions of the inverted U-shaped member include flanges mounted on the frame. 
     Having briefly described our invention, these and other features, advantages and objects of the present invention will be further understood and appreciated by those skilled in the art by reference to the following specification, claims and appended drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 is a side elevational view of the portable heater with the first unique support structure for supporting the heating unit above the plastic tank; 
     FIG. 1A is an enlarged view of a portion of the structure of FIG. 1; 
     FIG. 2 is a partial cross section taken along the plane II--II of FIG. 1; 
     FIG. 3 is a rear elevational view of the portable heater as disclosed in FIG. 1; 
     FIG. 4 is a front elevational view of the portable heater of FIG. 1; 
     FIG. 5 is a partial cross-sectional view taken along the plane V--V of FIG. 1; 
     FIG. 6 is a perspective view of the support structure for the saddle of the first embodiment as disclosed in FIGS. 1-5; 
     FIG. 7 is a side elevational view of a second embodiment of our portable heater; 
     FIG. 8 is an exploded perspective view of the support structure for the heater unit as disclosed in FIG. 7; and 
     FIG. 9 is a partial cross-sectional view taken along the plane IX--IX of FIG. 7. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENT 
     FIRST EMBODIMENT 
     Referring to the drawings, FIGS. 1-6 disclose one embodiment of the portable heater of this invention. Reference numeral 1 designates the portable heater which includes the heater unit 10 comprising a combustion chamber 11 located within the cowling 12 . A nozzle assembly 20 (FIGS. 1 and 2) is mounted at one end of the combustion chamber by the bracket 21 which also supports the ignitor 22 which in this instance is disclosed as a spark plug as is well-known in the art. The ignitor 22 is located immediately adjacent the nozzle 20 for igniting the fuel, which ignition is supported by an air supply means not disclosed. Suffice it to say that the combustion of the fuel takes place within the combustion chamber 11. 
     Located rearwardly of the heating unit 10 is a fan 30 driven by the motor 31 . The fan forces air through the heating unit 10 into the space to be heated. The nozzle is supplied fuel from the tank through the rigid tube 34. The nozzle assembly 20, fan 30 and fan motor 31 and other accessory items required to operate the heater are also located within the cowling 12 as is well-known in the art. It should be understood the aforegoing sketchy structural description of the components of the portable heater provides the environment for the improved combination of the present invention, the features of which will now be more particularly described. 
     Referring to FIG. 6 in conjunction with FIGS. 1-5, it should be understood that the important aspect of this invention resides in the utilization of a plastic tank and the structure as disclosed in FIG. 6 for supporting the heating unit 10 above the tank without exerting any substantial stress on the plastic tank. 
     Referring to FIGS. 1, 1A, and 3-5, the plastic tank 40 is formed of two parts, 41 and 42, secured together at their peripheries to form the top wall 43, the bottom wall 44, and the side walls 45. A capped opening 46 is provided through which fuel can poured into the interior of the tank 40. A second opening is provided in which a closure member having a threaded or tapped opening (not disclosed) receiving a fitting assembly 49 is provided for connecting the rigid tube 34 to a tube extending into the tank on the end of which is a filter 60. This entire connection is disclosed in the copending application Ser. No. 08/639,035, filed Apr. 16, 1996, now U.S. Pat. No. 5,766,003 and entitled SPACE HEATER WITH NOVEL FUEL LINE ASSEMBLY. This connection could also be the structure as disclosed in my copending application Ser. No. 08/976,922, filed Nov. 24, 1997, and entitled SPACE HEATER WITH NOVEL FUEL LINE ASSEMBLY. 
     As will be noted from FIGS. 1, 1A, and 3-5, the two parts 41 and 42 of tank 40 include flanges 41a and 42a extending around the entire periphery of the parts. These two flanges abut and are secured to each other to provide the enclosed tank 40. 
     Tank 40 is mounted on a wheeled frame 50 which includes an upper tubular member 51 having a horizontally extending portion 52 connected to a handle portion 53. Frame 50 also includes the lower tubular support member 54 extending horizontally below the tubular member 51 and bent downwardly to provide a foot 55 at the rear end and a forwardly bent portion 56 which supports the shaft 57 on which the wheels 58 are rotatably mounted. The side portions of the flanges 41a and 42a are secured between the tubular members 51 and 54 by bolts 59 extending through openings in the horizontal portions of the tubular members 51 and 54 and in the side portions of the flanges 41a and 42a all as best disclosed in FIG. 1A. 
     Now referring to FIG. 6, a support structure 60 for supporting the heating unit 10 is disclosed. It discloses a saddle structure comprising the end plates 61 and 62 both of which include the concave shaped flanges 63 and 64, respectively, having a curvature conforming to the curved shape of the cowling 12 of heater unit 10 so as to provide a curved surface to support the heater unit 10. The plates 61 and 62 are supported by the side support plates 65 and 66 by means of bolts 67 extending through the plates 65 and 66 and secured to flanges 68 of the plates 61 and 62. Plates 65 and 66 extend downwardly and are inclined outwardly of each other to provide the legs 69 and 70. Both legs 69 and 70 include flanges 69a and 70a, respectively. As disclosed in FIGS. 1 and 3-5, legs 69 and 70 extend downwardly beyond the sides of the top part 41 of plastic tank 40 and are secured between the tubular elements 51 and 53 by the bolts 58 extending through the openings 71 of the flanges 69a and 70a. Thus, the saddle formed by the flanges 63 and 64 of the plates 61 and 62 are supported entirely by the frame 50. This eliminates any stress being exerted on the top wall 43 of the plastic tank 40. 
     It will be noted as disclosed in FIGS. 3-5 that the top part 41 of tank 40 includes cutouts through which the legs 69 and 70 extend. This design permits the support plates 65 and 66 to be straight pieces as will be observed in FIGS. 5 and 6. It will also be noted that plates 65 and 66 include access openings 65a and 66a, respectively, for providing access to the inside of the compartment between the two plates 65 and 66. These openings 65a and 66a are normally covered by the cover plates 65b and 66b and are secured in place by the metal screws 65c and 66c. 
     SECOND EMBODIMENT 
     Another embodiment of this invention is disclosed in FIGS. 7-9. As will be noted, FIG. 7 does not disclose any of the components of the heater unit 10 except the outer cowling. It should be understood that in this second embodiment, the heater unit 10 is identical to that disclosed in relation to FIG. 1. 
     Now referring to FIG. 8, reference numeral 80 discloses the second embodiment of our invention which includes support structures for supporting the heater unit 10. The support structure 80 comprises two parts. The first part 81 is an inverted U-shaped support member having a bight portion 82 and the legs 83 and 84 on each side thereof. This U-shaped part 81 as disclosed in FIG. 9 has substantially the same configuration as the top part 41 of tank 40. It thus fits over the top portion 41 with the legs extending downwardly and including flanges 85 and 86 that extend between the two elongated tubular elements 51 and 54 on each side of the tank 40. The part 81 includes the upstanding flanges 87 and 88 both having openings 87a and 88a, respectively. 
     The second part 89 of the support structure 80 of FIGS. 7-9 provides a cradle support for heater unit 10 and is somewhat like the cradle support 60 of FIG. 6. Thus, it includes the two end plates 90 and 91 having flanges 92 and 93, respectively, with concave shapes corresponding to the shape of cowling 12 of heater unit 10. These end plates also include the flanges 94 like that of flanges 68 of FIG. 6. Plates 95 and 96 are mounted on the flanges 94 by screws 97. 
     The entire part 89 is secured to the flanges 87 and 88 by locating the end plates 90 and 91 between the flanges 87 and 88, respectively. The attachment is made by screws 97 extending through the openings 87a and 88a which are aligned when part 80 is inserted between the two flanges 87 and 88. 
     The assembly constituting the support structure 80 is secured to the frame 50 by inserting the flanges 41a and 41b between the frame members 51 and 54 and securing them together by bolts 59 extending through openings 71a as disclosed in FIGS. 1A and 9. 
     It should be evident from the description of the cradle supports described above in the first and second embodiment that the second embodiment also protects the tank 40 from any substantial stress exerted by the weight of the heater unit as it is mounted above the tank. 
     While we have described specific structural features of our invention, it should be understood that the invention is not limited to such specific features and that other forms or modifications made within the spirit of this invention are conceivable within one skilled in the art. Therefore, this invention shall be limited only within the legitimate and valid scope of the appended claims.