Abstract:
A hinged hold-open assembly for roof ventilator lids is provided, comprising a pair of hinged assemblies attached between the lid and a vent base, wherein each hinged assembly includes a hinge member; a retainer bracket affixed to the vent base, wherein the retainer bracket includes an extended member having a plurality of position holes corresponding to a closed position and a plurality of open positions; a position arm affixed to the lid, wherein the position arm includes a locking hole alignable with one of the position holes of the retainer bracket; and a locking device adapted to insert into both the locking hole and the position hole when said holes are aligned.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This nonprovisional application claims the benefit of priority to U.S. provisional application Ser. No. 62/151,307, filed on Apr. 22, 2015. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates generally to devices and methods used in rooftop ventilator systems, and more particularly to hinged hold-open devices that can be used to retain the cover in multiple positions for maintenance activities. 
     2. Description of Related Art 
     In commercial ventilation systems for buildings, larges fans are mounted over vents in a roof. For example, a fan-assisted vent at a restaurant permits an exhaust to be withdrawn from the kitchen. Through this vent, grease and other cooking residue are allowed to leave the building. After a period of use, the vent and the fan become contaminated with grease. Other cooking residue also becomes adhered to the fan blades and other surfaces. Such residue can be flammable and presents a fire hazard, and can also attract undesirable microbes and illness causing bacteria, requiring occasional cleaning. 
     In most of these systems, a rectangular base rises above the roof vent, and the open base is covered by a rectangular lid. The lid is sometimes referred to as a shoebox lid, because is similar in construction to a cardboard shoebox, but formed from sheet metal. A large hole exists in the lid, and the fan is securely mounted to the lid. Over time the fan becomes dirty and requires cleaning and maintenance. For maintenance purposes, the lid is typically hinged to the base, allowing a worker to raise the lid and rotate the lid and fan assembly away from the base for proper access. 
     The problem for many workers is that the lid can be difficult to grasp, requiring the worker to lift the edges of the lid with fingers, and then rotate the heavy fan and lid assembly back into a fixed open position. Given the dangers of the fan and lid assembly inadvertently falling in either direction, it is important to place it into the desired position safely and securely. Moreover, it is also important that the maintenance worker have the flexibility to position the fan and lid into a plurality of positions. 
     Therefore, there is a need for a device which can be attached to the lid and fan base that serves as a replacement hinge and which allows easier and safer positioning of the lid in an open configuration when maintenance is required. The device should be simple to install and use, and it should not require any irreversible modifications to the lid itself. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a further understanding of the nature, objects, and advantages of the present invention, reference should be had to the following detailed description, read in conjunction with the following drawings, wherein like reference numerals denote like elements. 
         FIG. 1  shows a preferred embodiment of a hinged hold-open assembly of present invention showing the lid in an open position. 
         FIG. 2  shows a more detailed view of the hold-open assembly of  FIG. 1 . 
         FIG. 3  shows a view of the hinge assembly of  FIG. 1 . 
         FIG. 4  shows an alternative embodiment of a hinge assembly for holding open the lid, depicting the front of the hinge. 
         FIG. 5  shows the rear of the hinge of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is a hinged hold-open assembly which allows the lid on a rooftop ventilator to be locked into one of a plurality of positions. 
     As shown in the preferred embodiment of  FIGS. 1 and 2 , a fan  1  is fixed to a lid  2  which covers a vent base  3 , wherein the fan  1  and lid  2  are hinged relative to the vent base  3 . A pair of hold-open hinge assemblies  4 A,  4 B are operatively connected between the lid  2  and the vent base  3 . The hold-open hinge assemblies  4 A,  4 B are constructed as described below, and they serve to lock the position of the lid  2  into a desired position for maintenance. 
     As shown in more detail in  FIGS. 2 and 3 , each hold-open hinge assembly  4 A,  4 B comprises a hinge  5 , having an upper hinge plate  6  and a lower hinge plate  7 . The upper hinge plate  6  includes mounting holes  20  and is fastened to the lid  2  using conventional bolts or screws (not shown for clarity, but identical to fasteners  30 A in  FIG. 4 ) inserted through mounting holes  20 . The fasteners  30 A which secure the upper hinge plate  6  to the lid  2  also function as set screws. For example, upper hinge plate  6  includes an integrated rear plate  6 A which is formed by bending behind upper hinge plate  6 , such that a channel is formed. The lid  2 , which is typically a “shoe box” style lid, slides into the channel formed between upper hinge plate  6  and rear plate  6 A, and is retained by the set screw fasteners  30 A. 
     Lower hinge plate  7  is also fastened to the vent base  3  by conventional fasteners which are inserted through mounting holes  21  in the lower hinge plate  7 . A retainer bracket  8  is fastened to the vent base  3  and co-located with the lower hinge plate  7 , wherein the retainer bracket  8  includes a plurality of position holes  9  formed in an arcuate path therein. At least two of the mounting holes  21 A in the retainer bracket  8  can be formed larger to fit over fastener heads, while the remainder of the mounting holes  21  may simply allow for simultaneous fastening of both retainer bracket  8  and lower hinge plate  7 . The locations of the position holes  9  in the retainer bracket  8  correspond to the path of a position arm  10  fastened to the lid  2 , and co-located with the upper hinge plate  6 . The position arm  10  includes a locking hole  11  which can be aligned with any of the position holes  9 . 
     For example, when the lid  2  is closed, the locking hole  11  of the position arm  10  is aligned with the uppermost position hole  9  of the retainer bracket  8 . As the lid  2  is opened, the position arm  10  travels along a downward arc, such that the locking hole  11  passes one or more position holes  9 . As shown in  FIG. 2 , the lid  2  has been opened to approximately a 60 degree angle, causing the locking hole  11  to align with the sixth position hole  9 . A locking device  12 , such as a padlock as shown or a conventional pin and retainer, can be inserted into the aligned holes  9 ,  11  to retain the lid  2  in the desired position. 
       FIGS. 4 and 5  show an alternative embodiment of the present invention.  FIG. 4  is a front view depicting a hinge  35 , having an upper hinge plate  36  and a lower hinge plate  37 .  FIG. 5  shows a rear view of the hinge  35 . The upper hinge plate  36  includes mounting holes  30  and is fastened to the lid  2  using conventional bolts or screws  30 A inserted through mounting holes  30 . The fasteners  30 A which secure the upper hinge plate  36  to the lid  2  also function as set screws. For example, upper hinge plate  36  includes an integrated rear plate  36 A which is formed by bending behind upper hinge plate  36 , such that a channel  36 B is formed. The lid  2 , which is typically a “shoe box” style lid, slides into the channel  36 B formed between upper hinge plate  36  and rear plate  36 A, and is retained by the set screw fasteners  30 A. Upper hinge plate  36  further includes hinge members  41 A,  41 B which are formed to reside in a flush relationship with corresponding members of lower hinge plate  37  as described below. 
     Lower hinge plate  37  is also fastened to the vent base  3  by conventional fasteners which are inserted through mounting holes  31  in the lower hinge plate  37 . Lower hinge plate  37  further includes hinge members  42 A,  42 B which are formed to reside in a flush relationship with hinge members  41 A,  41 B of upper hinge plate  36 . In this configuration, nut and bolt hinge axes  43 A,  43 B are inserted through hinge members  41 A,  42 A, and also hinge members  41 B,  42 B, respectively, resulting in an assembly which allows upper hinge plate  36  to hingedly rotate relative to lower hinge plate  37 . 
     Lower hinge plate  37  further includes a retainer portion  48  which includes a plurality of position holes  59  formed in an arcuate path therein. Upper hinge plate  36  further includes a position arm  44  which includes a locking hole  51  which can be aligned with any of the position holes  59  in the retainer portion  48 , similar to the operation of the preferred embodiment of  FIGS. 1-3 . A locking device  12 , such as a padlock as shown in  FIGS. 1-3  or a conventional pin and retainer as shown in  FIG. 4 , can be inserted into the aligned holes  51 ,  59  to retain the lid  2  in the desired position. 
     The hinged hold-open assembly  4 A,  4 B of  FIGS. 1-3 , as well as the alternative embodiment of the hinge  35  shown in  FIGS. 4 and 5 , are generally produced from a 10ga cold rolled low carbon steel, although other suitable materials may be used, such as aluminum. Being made of general metal material, the product will be either plasma cut, water jet cut, laser cut, punched or stamped from sheets or rolls of metal although new and better forms of parting the metal may be used as those methods become available. Once flat blanks of the various parts are produced using metal, the flat blanks will be formed using a press or die and generally powder-coated. If desired per customer request or specific design needs, final surfacing may be improved for the product&#39;s abilities to combat environmental conditions once in service, or to meet other desired characteristics. 
     All references cited in this specification are herein incorporated by reference as though each reference was specifically and individually indicated to be incorporated by reference. The citation of any reference is for its disclosure prior to the filing date and should not be construed as an admission that the present invention is not entitled to antedate such reference by virtue of prior invention. 
     It will be understood that each of the elements described above, or two or more together may also find a useful application in other types of methods differing from the type described above. Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention set forth in the appended claims. The foregoing embodiments are presented by way of example only; the scope of the present invention is to be limited only by the following claims.