Abstract:
Horizontal hinged door assemblies such as sidewalk doors comprising a door, a frame surrounding the door and a hinge connecting the door to the frame are improved by utilizing a bendable gasket having a leg portion which is preferably inserted into an opening in at least one of the frame walls to secure the gasket to the frame and an outwardly and preferably downwardly extending body portion which extends across a gap between the frame and the edge of the door when closed and which is contacted by the door and bent further downward when the door is closed. The bendable gasket may be inserted into and secured to the frame during fabrication of the door assembly or on-site during installation of the door assembly. A variety of elongated shaped bendable gaskets may be used depending on the type door assembly installation.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to horizontal hinged door assemblies such as sidewalk access doors and, in particular, to a gasket system for such door assemblies which comprise a door, a frame surrounding the door, preferably a peripheral channel frame to prevent water and dirt from falling through to the area below covered by the door, and a hinge connecting the door to the frame for rotation about an axis, the gasket system restricting water and dirt from entering a gap between the frame and the edge of the door. 
     2. Description of Related Art 
     Horizontal hinged (covers) doors are commonly used for access doors, roof scuttles, automatic fire vents, ceiling access doors, basement doors and for pit, floor and sidewalk doors for access to subterranean locations. While the present description will be directed to pit, floor and sidewalk doors, it will be appreciated that the invention can be used for any such horizontal doors, such as angled bulkhead doors for entering or leaving a basement, where there is a gap between the frame of the door and the edge of the door through which gap water or dirt may enter. 
     Pit, floor and sidewalk doors are used in a variety of applications for providing access through openings in a concrete slab, wood floor or ceiling, and the like into a pump pit, utility vault, pipe trench, basement, building, etc. Most of the designs for these type doors utilize a channel frame surrounding the door which frame may be connected to a drain. The typical door assembly necessarily has a small gap between the frame and the edge of the door through which water and dirt enters and the drain directs rain water away and the channel restricts dirt from falling through to the covered area below. 
     The channel frame is usually made of ¼ metal such as extruded aluminum and is generally a U-shape. The thickness of the frame is usually up to about ½ inch, typically ¼ inch. The dimensions of the U-shape channel may vary widely up to, for example, 5 inch high by 5 inch wide or larger. A typical U-frame is made of ¼ inch thick extruded aluminum with the frame being about 3.5 inch high by 3 inch wide. The channel frame is made as a continuous extrusion and is cut to the proper length and the four sides of the assembly connected together to form the frame. The frame is positioned at the periphery of the hole opening to which the frame is secured. The top of the outer wall of the channel frame typically has an inward flange extending around the periphery of the channel for strength and to facilitate hinge connection to the door. The height of the inner wall of the frame is generally slightly lower than the outer wall to accommodate the thickness of the door when the door is closed. The door is generally up to about ⅜ inch thick, typically ¼ inch. When the door is in the closed position, the door rests on the inner wall and the door is flush with the inward flange of the channel frame. 
     The door covers an opening and there is necessarily a gap due to manufacturing tolerances and operational clearances between the edges of the door and the frame of the door assembly. It is important to keep rain water, dirt and other debris from entering the gap and falling into the frame and/or opening covered by the door assembly. Additionally, dirt and debris can accumulate in the frame or on the frame walls lifting the door above the sidewalk or floor level causing a tripping hazard and possible hinge and door damage. 
     In a prior art horizontal door assembly shown in FIG. 3, a gasket  43  is used between two confronting surfaces comprising the door  14  and flange  42  of the channel frame  40 . The top portion  44  of gasket  43  is compressed between the door  14  and channel flange  42 . This type design has certain drawbacks such as a need for continual maintenance of the gasket, the buildup of dirt on the gasket surface and the need for a confronting flange to support the gasket. 
     Bearing in mind the problems and deficiencies of the prior art, it is one object of the present invention to provide a bendable gasket structure for use with a horizontal door to restrict water, dirt and debris from entering a gap between the door frame and edges of the door. 
     It is an additional object of the invention to provide a horizontal hinged door assembly having a bendable gasket structure as part of the assembly which gasket restricts water, dirt and debris from entering a gap between the door frame and edges of the door. 
     It is another object of the invention to provide a horizontal hinged door assembly and/or a frame member used to make horizontal door assemblies which are adapted to utilize a bendable gasket structure of the invention which gasket extends across a gap between the door frame and edges of the door to restrict water, dirt and debris from entering the gap. 
     Other objects and advantages will be apparent from the following description. 
     SUMMARY OF THE INVENTION 
     The present invention comprises a horizontal hinged door assembly for enclosing an opening, the door assembly comprising: 
     a plurality of elongate frame members, preferably comprising a channel frame and is generally U-shaped, which frame members are connected together to form a frame for the door assembly, the frame members preferably having opposed outer and inner walls and a connecting lower wall and at least one opening or recess in the inner surface of the outer wall of at least one of the frame members and preferably in all of the frame members with the opening opposed to the edge of the door when closed; 
     a hinge; 
     a door hingedly mounted to a frame member for motion between an open and closed position wherein when the door is in the closed position there is a gap between the outer wall of the frame and the edge of the door; and 
     an elongate bendable gasket preferably comprising a leg portion which is inserted into any of the frame openings to secure the gasket to the frame and a body portion which extends outwardly from the wall of the frame member and which body portion of the gasket extends across the gap and is bent downwardly by the door when the door is in the closed position. 
     The frame member is preferably a channel frame and is generally U-shaped and preferably has a transverse inwardly extending flange at the upper end of the outer wall which extends partially into the channel opening formed by the channel frame and which flange contains the recess to hold the gasket. The frame member may comprise other shapes as is well known in the art. The height of the inner wall of the channel frame is slightly lower than the height of the outer wall to accommodate the door when closed so that the closed door is flush with the upper end and flange of the outer wall of the channel frame. 
     The gasket device is of a material and thickness sufficient to provide the necessary strength for sealing the door over a long period of use. The gasket devices are preferably a resilient material such as an elastomer, rubber, polymer, etc. The shape of the gasket will vary depending on the desired configuration and generally comprises a leg portion which is inserted into an opening of the frame member to secure the gasket to the frame and a body portion which extends outward from the frame member and preferably downward from the plane of the closed door so that dirt or other debris will not settle and remain on the gasket surface when the door is open. The gasket device and especially the body portion is bendable by the door and covers a gap between the door frame and edge of the door and the gasket is preferably secured to the frame member by inserting the leg portion of the gasket device into the frame member of the door assembly. 
     In a further aspect of the invention, a bendable gasket device is provided for use to cover a gap in a horizontal door between the door frame and door edge wherein preferably a leg portion of the gasket device is inserted into an opening in the frame member and a body portion of the device extends outward from the wall and is bendable by the door when closed. 
     In an additional aspect of the invention, the opening or recess in the frame member is preferably a longitudinal slot running the length of the frame member so that the gasket device can preferably be continuous along the length of the frame member or one or more gasket devices inserted at any point along the length of the frame member. This type frame member design is economical from a manufacturing standpoint because the frame member would be extruded as a continuous member with the slot therein. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a full understanding of the invention, reference should be made to the following description taken in connection with the accompanying drawings in which: 
     FIG. 1 is a perspective view of a double leaf, flush mounted door assembly, one leaf being open to show the peripheral channel frame member. 
     FIG. 2 is a partial cross-sectional side view along the line  2 — 2  in FIG. 1 showing the channel frame modified according to the present invention to accommodate a gasket of the invention. 
     FIG. 3 is a partial cross-sectional side view of a prior art channel frame employing a compressible gasket to seal the gap between the frame and door edge. 
     FIGS. 4A and 4B show side views of gaskets of the invention. 
     FIG. 5 is a side view of a gasket of the prior art. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to FIG. 1, a horizontal double leaf door assembly for enclosing an opening  11  according to the present invention is generally indicated by reference no.  10 . The assembly is shown cast-in-place in a concrete floor  13  which floor is at the same level as the door leafs  12  and  14 . One door leaf  12  is open to show the internal support structure and counterbalancing mechanism typical of these type door assemblies. Door leaf  14  is shown in the closed position. Door leaf  12  is shown horizontally hinged to flange  17  of an outer wall of channel frame  20  with hinges  24   a  and  26   a  and supported by spring lift mechanism  35 . Inner wall  16  is lower than flange  17  and outer wall  15  (not shown) to accommodate the thickness of the door leaf  12  or  14 . Door leaf  12  is shown with cross ribs  28  and long ribs  30  for support and L-slot  32  is provided to engage door handle  34 , which is connected to support strut  33 . Door leaf  14  is shown hinged to channel frame  15  by hinges  24   b  and  26   b . A gap  39  is typically between the end of shoulder  17  and the edge of door  14  due to manufacturing tolerances and operational clearances to facilitate opening and closing the door. The gap  39  typically extends around the periphery of the door and it is through this gap that rain water, dirt and debris enter the channel opening  21  and the opening  11  covered by the door assembly  10 . The invention may also be used with single leaf doors as will be apparent to those skilled in the art. 
     Referring to FIG. 2, door leaf  14  can be seen in the closed position. Channel frame  20  has a channel  21  formed by outer wall  15 , opposed inner wall  16  and a connecting lower wall  19 . The frame  20  extends around the periphery of the opening and the frame is generally formed by connecting frame members  20  together by welding at the corners. The outer wall  15  has on the upper end thereof, an inwardly extending flange  17  and a gap  39  is typically formed between the end of flange  17  and the edge of door  14 . 
     Leg portion  29  of gasket  22  is shown inserted in frame member opening  18  in flange  17 . A body portion  31  of the gasket extends outward from the end of flange  17  of the channel frame  20 . The body portion  31  is shown in a bent position at angle θ B  resulting from the edge of door  14  contacting and forcing body portion  31  downward. Body portion  31  is shown in phantom in the relaxed non-bent position. The body portion  31  in the relaxed position is also preferably angled downwardly shown as angle θ s  so that dirt, water, etc. do not accumulate on the surface of the gasket. 
     The channel frame  20  is preferably constructed with a thicker flange ∫in which gasket openings  18  are to be provided. The wall portion  47  of the flange  17  is of a thickness sufficient to support the gasket and typically will be {fraction (1/4 )} to ½ inch thick or more. The leg portion  29  of the gasket may vary widely and is generally up to about ½ inch long and preferably about ⅛ to ¼ inch long. The length of the body portion will likewise vary widely to extend across the gap and will generally be up to about ½ inch in length, usually {fraction (3/16)} to ⅜ inch. The opening  18  and leg portion  29  are configured to lock the leg portion into the opening to secure the gasket to the frame. The gap  39  between the frame and door edge may vary and is usually about ⅛ to ¼ inch. A gasket  48  is typically disposed at the top of inner wall  16  to provide an additional seal between the door and channel frame. 
     The gasket  22  shown in FIG. 2 comprises a downwardly angled body portion  31  and a shorter horizontal leg portion  29 . Leg portion  29  has a protrusion  36  at the back end thereof to provide a force fit with a corresponding shoulder in the frame opening  18 . In use, gasket  22  would be secured in channel frame  20  by forcing leg portion  29  into the frame opening  18 . 
     As seen from the drawings, the door assembly of the present invention may be conventionally manufactured with the exception that the channel frame contains openings or recesses which are preferably formed in the frame member manufacturing (extrusion) process. The openings are preferably slots which run the length of the frame and which are easily made during an extrusion process forming the frame member. The gasket  22  is manufactured separately and attached to the door assembly on-site by the installer or during fabrication of the door assembly. The gasket typically runs the length of the frame member or a plurality of gaskets may be used along the length of the frame member such as when the wall of the frame member containing the opening is obstructed by the hinges. 
     Referring to FIG. 3, a cross-sectional view of a horizontal door having a prior art compressible gasket is shown. The channel frame  40  has an outer wall  15 , an inner opposed wall  16  and a lower connecting wall  19 . The channel frame  40  also has an inwardly extending flange  17  at the upper end of outer wall  15 . The flange  17  has a downwardly extending member  41  and an inwardly extending confronting flange  42  extending across gap  39  for supporting a gasket. A gasket shown generally as  43  has a lower portion  45  and an upper portion  44  which is secured to flange  42  by a force fit. The upper portion  44  of gasket  43  is shown compressed against confronting flange  42  by the closed door  14 . When the door is open, the gasket  43  will be in a relaxed position with the upper surface  44  resting on flange member  42 . 
     The compressible gasket design shown in FIG. 3 has serious drawbacks when compared to the bendable gasket and horizontal door assembly of the present invention. For example, when the door  14  is closed any debris or other matter in the gap between the frame and the door could break flange member  42  or bend channel frame  17  depending on the strength of flange member  42 . The compressible gasket  43  is also subjected to severe forces if any debris is on the surface of the gasket when the door is closed. 
     The horizontal door assembly and gasket system of the present invention overcomes the problems of a compressible gasket since it is only the gasket which is effectively contacted by the door and since the gasket is bendable there is no possibility of the frame being bent or otherwise damaged when the door is closed. The forces on the bendable gasket are also much less than the forces on a compressible gasket and the life of the bendable gasket and horizontal door assembly of the present invention is greatly enhanced compared to the prior art design. The body portion of the bendable gasket is subjected to a bending moment by the door and covers the gap and the gasket may be reinforced to provide long wear. For example, as shown further hereinbelow shoulders may be provided on the gasket at the intersection of the flange opening and the body portion of the gasket. The gasket, when contacted and forced downward by the door, is not in a compressed state and accordingly does not have the severe compressive forces thereon as the compressive gaskets in horizontal door assemblies of the prior art. 
     Referring to FIGS. 4A and 4B, two gaskets of the invention are shown. FIG. 4A shows the gasket  22  employed in the door assembly of FIG.  2  and comprises an elongated leg portion  29  having a protuberance  36  at the back end thereof for locking the gasket into the frame. An elongated body portion  31  extends preferably at a downward angle θ s  and which body portion is bent downward when the door is closed in the direction of the arrow to form an angle θ B . The gasket has shoulders  37 A and  37 B which rest against the wall  47  of the frame to provide additional strength to the gasket and enhanced bending life during use of the door assembly. 
     Referring to FIG. 4B, another gasket  22  of the invention is shown again having an elongated leg portion  29  having a protuberance  36  at the back end thereof. The body portion extends outward from the leg portion and preferably forms a downward angle θ s  in the relaxed position. When the gasket is bent downward in the direction of the arrow by the closing door, the bent body portion is shown in phantom forming a downward angle θ B . 
     Referring to FIG. 5, a compressible gasket of the prior art is shown as  43 . The gasket has a lower portion  45  and an upper open portion  44 . The gasket is secured to the frame of the door by a force fit over an extending flange  42 . When the door is closed in the direction of the arrow, the upper portion  44  of the gasket is compressed as shown in phantom. Any dirt or debris on the surface of gasket  43  will also be compressed against the gasket and provides compressive forces against the upper portion  44  of gasket. Also, the upper portion of the gasket  44  is compressed against the flange securing the gasket providing further compressive forces against the gasket. This is to be contracted with the bending forces on the gaskets of the invention shown in FIGS. 4A and 4B. 
     It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the above constructions without departing from the spirit and scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. 
     While the invention has been illustrated and described in what are considered to be the most practical and preferred embodiments, it will be recognized that many variations are possible and come within the scope thereof, the appended claims therefore being entitled to a full range of equivalents.