Abstract:
A sealing system seals the perimeter of insulated hinged double doors. The sealing system includes first and second exterior seals made of a monolithic, resilient and elastically deformable material. The first exterior seal has an elongated lobe for contacting the exterior of said door, and both of the first and second exterior seals have an interior lobe which contact one another when the doors are closed. The sealing system further includes first and second inner seals made of a monolithic, resilient and elastically deformable material, each having a pair of spaced-apart sealing lobes. The inner seals are mounted to respective doors in a staggered fashion, such that the respective pairs of sealing lobes interact with one another to create a redundant, weather-resistant and thermally robust seal when the double doors are closed.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit under Title 35, U.S.C. §119(e) of U.S. Provisional Patent Application Ser. No. 61/881,783, filed on Sep. 24, 2013 and entitled TRAILER DOOR SEAL, the entire disclosure of which is hereby expressly incorporated by reference herein. 
    
    
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to seals, and in particular, to seals that are adapted to seal doors such as those associated with semi-trailer trucks, boxcars, shipping containers, and buildings. 
     2. Description of Related Art 
     Seals that are used on the doors of truck trailers may be designed to help insulate the contents contained within, and may be formed as a plurality of separate door-edge sections that are joined at their respective corners using molded corner blocks joined to adjacent pairs of the door-edge sections via glue or silicone caulk, for example. These multi-piece seals may be expensive and difficult to install and maintain. 
     Other seals may be pre-formed to fit a given truck door size. These seals normally cannot be substantially deformed without compromising the effectiveness of the seal, and are therefore packaged and shipped as a single, door-shaped piece in a large, flat shipping container having approximately the same dimensions as the door to which the seal will be mounted. This relatively large shipping size and configuration adds to the overall cost of implementing such a pre-formed seal. 
     What is needed is an improvement over the foregoing. 
     SUMMARY 
     A sealing system is provided for sealing the perimeter of insulated hinged double doors. The sealing system includes first and second exterior seals made of a monolithic, resilient and elastically deformable material. The first exterior seal has an elongated lobe for contacting the exterior of said door, and both of the first and second exterior seals have an interior lobe which contact one another when the doors are closed. The sealing system further includes first and second inner seals made of a monolithic, resilient and elastically deformable material, each having a pair of spaced-apart sealing lobes. The inner seals are mounted to respective doors in a staggered fashion, such that the respective pairs of sealing lobes interact with one another to create a redundant, weather-resistant and thermally robust seal when the double doors are closed. 
     In an exemplary embodiment, the seal is formed from an elastomeric material that is elastically deformable, resilient, compressible and packable by rolling, stuffing or folding into a compact space. The seal material retains a constant deformation force over an extended period of time, and accommodates repeated deformations while maintaining a fluid-tight seal that seals the inside of the trailer from the outside environment. The elastic deformation and monolithic, one-piece design simplifies installation as the seal will stretch over the door and hold itself in place. Moreover, the seal is both weather resistant in subzero temperatures and resistant to degradation by UV exposure. 
     In one form thereof, the present disclosure provides a sealing system for sealing a space between a pair of hinged doors, said sealing system comprising: a first inner seal having a first inner lobe and a first outer lobe defining a first lobe receiving space therebetween; and a second inner seal having a second inner lobe and a second outer lobe defining a second lobe receiving space therebetween, the first lobe receiving space sized to receive the second outer lobe such that the second outer lobe sealingly abuts the first inner lobe and the first outer lobe, and the second lobe receiving space sized to receive the first inner lobe such that the first inner lobe sealingly abuts the second inner lobe and the second outer lobe, whereby the first inner seal and the second inner seal are arrangeable in a staggered fashion to form a redundant, weather-resistant and thermally robust seal in a space between two doors. 
     In another form thereof, the present disclosure provides a sealing system for sealing a space between a pair of hinged doors, said sealing system comprising: a first hinged door pivotable between a first open position and a first closed position; a second hinged door pivotable between a second open position and a second closed position, the first and second hinged doors having adjacent vertical edges which swing outwardly and away from one another as the first and second hinged doors pivot from the first and second closed positioned toward the first and second open positions respectively; a first inner seal attached to the first hinged door and having a first inner lobe and a first outer lobe defining a first lobe receiving space therebetween; and a second inner seal attached to the second hinged door and having a second inner lobe and a second outer lobe defining a second lobe receiving space therebetween, the first inner seal attached in a staggered arrangement with respect to the second inner seal such that, when the first and second doors and in the first and second closed positions respectively, the first lobe receiving space sealingly receives the second outer lobe and the second lobe receiving space sealingly receives the first inner lobe to form a redundant seal in a space between the first and second hinged doors. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above-mentioned and other features and advantages of this disclosure, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following descriptions of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a rear perspective view of a semi-trailer truck including doors that are fitted with seals according to the present disclosure; 
         FIG. 2  is a cross-sectional view of a truck door sealing system in accordance with the present disclosure, taken along line  2 - 2  of  FIG. 1 ; 
         FIG. 3  is another cross-sectional view of the seal shown in  FIG. 2 , taken along line  2 - 2  of  FIG. 1 , in which one door is illustrated in a closed position and the other door is approaching a closed position; 
         FIG. 4  is a partial cross-sectional view of another embodiment of an outer truck door seal in accordance with the present disclosure, taken along line  2 - 2  of  FIG. 1 ; and 
         FIG. 5  is a partial cross-sectional view of the installation process of a truck door seal in accordance with the present disclosure, taken along line  2 - 2  of  FIG. 1 . 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate exemplary embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the disclosure in any manner. 
     DETAILED DESCRIPTION 
     Large trucks, such as semi-trailer trucks, often need seals at the rear opening of a cargo trailer between the trailer&#39;s rear frame and a pair of hinged rear doors used to close the trailer. Additional sealing is also often needed between the rear doors themselves. 
     The present seal arrangement provides one-piece, monolithic seals designed for installation on respective hinged trailer doors for semi-trailer trucks, and particularly the thick hinged doors associated with insulated cargo trailers (e.g., of the type used for transport of frozen or cold cargo). Each one-piece seal is made of four individually extruded sections, or extrusion members, which are made of a resilient, elastically deformable/compressible material. The extrusion members are heat fused or welded together to form a four-sided, one-piece, monolithic seal having a closed profile sized to fit a particular door. This one-piece design of the respective seals used in the present seal arrangement ensures that there is no leak path across each seal when the seals are placed on a door of a semi-trailer truck, while also inhibiting thermal transfer around the periphery of the closed double doors. 
     While the seals of the present disclosure are discussed in terms of semi-trailer truck doors, other uses are also contemplated. For example, doors on shipping containers, railroad boxcars and buildings may be used with seals that extend around the entire perimeter of such doors and that are made in accordance with the present disclosure. Moreover, any aperture or opening that is sealingly blocked with a cover of comparable size and shape may benefit from the application of seals made in accordance with the present disclosure. 
     Referring now to  FIG. 1 , trailer  10  of a refrigerating semi-trailer truck is shown having cooling unit  12  and cargo box  15 . Cargo box  15  has five sides sealed to one another to define a cargo space therein, with an open sixth side of cargo box  15  sized to transfer cargo to and from the cargo space. This open sixth side of cargo box  15  is selectively closed by a rear door assembly including a generally rectangular rear frame  16  and a pair of hinged doors  18  and  20 . As illustrated, the double hinged arrangement of doors  18  and  20  is a “French door” type in which opposite vertical edges of doors  18 ,  20  are hinged to adjacent vertical members of rear frame  16 , while the adjacent vertical edges of doors  18 ,  20  near the middle of the opening in rear frame both swing outwardly and away from one another as doors  18  and  20  are pivoted from the closed position to the open position. 
     1. Seal Configurations and Characteristics 
     In the following description, the terms “inner,” “interior” and other like terms denote a position relatively closer to the interior (i.e., cargo space) of cargo box  15  ( FIG. 1 ). Conversely, terms such as “outer,” “exterior” and other like terms denote a position that is relatively distanced from the interior of cargo box  15  ( FIG. 1 ). For example, if a pair of structures include an “inner” structure and an “outer” structure, the “inner” structure is closer to the interior space of cargo box  15  relative to the “outer” structure, while the “outer” structure is closer to the ambient space outside of cargo box  15  relative to the “inner” structure. 
     In general, referring to  FIG. 2 , to seal the gap between doors  18  and  20 , first exterior seal  22  sealingly engages second exterior seal  24  and first inner seal  42  engages second inner seal  40 , to form a dual, gap-bridging seal interaction.  FIG. 3  illustrates a cross-sectional view of doors  18  and  20  in a partially-open configuration, with door  20  in a closed position and door  18  approaching a closed position. More particularly, first door  18  is shown pivoting from an open position toward a closed position along the direction of arrow A. In the exemplary embodiment shown in  FIG. 1 , second door  20  is also able to pivot between open and closed positions in a similar fashion. If it is desired for second door  20  to be closed upon first door  18  (i.e., the reverse of the arrangement shown in  FIG. 3 ), first and second exterior seals  22  and  24  and first and second seals  42  and  40  may be interchanged. 
     Referring to the closed and sealed configuration of doors  18  and  20  as shown in  FIG. 2 , first exterior seal  22  has an elastically deformable, pliable body including mounting portion  26 , which fits within mounting opening  114  of door frame  102 , and sealing portion  28 . Both mounting portion  26  and sealing portion  28  are formed integrally with one another as a single, monolithic structure, such as via extrusion. Sealing portion  28  includes first sealing lobe  30  and second sealing lobe  32 . First sealing lobe  30  has an elongate, arcuate profile that spans the gap between doors  18  and  20  and is substantially aligned with and seated upon the exterior of outer connecting wall  106  of door frame  102  when doors  18 ,  20  are closed. As described in further detail below, sealing lobe  30  presents an initial, outer physical and thermal barrier between the exterior and interior of cargo box  15  through the gap between doors  18  and  20 . 
     Second sealing lobe  32  includes elliptical hollow  33 , which aids in producing a controlled, repeatable compression of second sealing lobe  32  against lobe  36  when doors  18  and  20  are in the closed position, as also described further below. Second sealing lobe  32  therefore cooperates with the adjacent lobe  36  to provide a second, inner thermal and physical barrier disposed inwardly of outer sealing lobe  30 . 
     Second exterior seal  24  has an overall shape and configuration similar to first exterior seal  22 , except without exterior sealing lobe  30  as best seen in  FIG. 3 . Second exterior seal  24  includes mounting portion  34 , which fits within opening  124  formed on door frame  104  and may have the same cross-sectional profile of mounting portion  26  of seal  22 . Sealing lobe  36 , which extends from mounting portion  34 , includes elliptical hollow  38  similar to sealing lobe  32  of seal  22 . When doors  18 ,  20  are in their respective closed configurations ( FIG. 2 ), sealing lobe  36  resilient deforms against sealing lobe  32  such that both of elliptical hollows  33 ,  38  are compressed, and sealing lobes  32 ,  36  cooperate to sealingly bridge the gap between doors  18  and  20 . 
       FIG. 4  illustrates an alternative exterior trailer door seal arrangement in accordance with the present disclosure. The embodiment of  FIG. 4  includes first and second exterior seals  70  and  74  which cooperate to provide an initial, external seal against ingress of fluid or contaminants similar to seals  22 ,  24  described above. Like first exterior seal  22 , first deformable, pliable body including mounting portion  76  and first sealing lobe  80 , which are integrally and monolithically formed as a single structure. Sealing lobe  80  has an elongate, arcuate profile that spans the gap between doors  18  and  20  and is substantially aligned with and seated upon the exterior of outer connecting wall  106  of door frame  102  when doors  18 ,  20  are closed. However, seals  70 ,  74  lack a structure analogous to mutually abutting sealing lobes  32 ,  36 . Rather, first exterior seal  70  has bumper  72  and second exterior seal  74  has bumper  78 , both of which partially span the gap between the doors when doors  18  and  20  are in the closed position and provide for firm fixation of seals  70 ,  74  within mounting openings  114  and  124  respectively. 
     Turning again to  FIGS. 2 and 3 , the present seal arrangement may further include first and second dual inner seals  42  and  40  installed to doors  18  and  20 , respectively. First inner seal  42  (shown in  FIG. 3  in its undeformed configuration) includes inner lobe  54  and outer lobe  56 , which are connected to one another by connecting portion  58  to form a unitary, monolithically formed dual-lobe structure Inner lobe  54  includes inwardly-facing wall  51  and outwardly-facing wall  53 , while outer lobe  56  similarly defines inwardly-facing wall  55  and outwardly-facing wall  57 . Together, inwardly-facing wall  55 , connecting portion  58 , and outwardly-facing wall  53  define lobe receiving space  60 , which facilitates an interlocking seal between first and second dual inner seals  42  and  40  as will be described further below. First dual inner seal  42  includes generally cylindrical hollows  66  and  68  which facilitate deformation of seal  42  upon establishment of the interlocking seal. 
     Second inner seal  40  may have a cross section similar or identical to first inner seal  42 . As best shown in  FIG. 3 , second inner seal  40  includes inner lobe  44  and outer lobe  46 , which are joined together by connecting portion  48  into a unitary, monolithically formed dual-lobe structure. Inner lobe  44  includes inwardly-facing wall  41  and outwardly-facing wall  43 , while outer lobe  46  includes inwardly-facing wall  45  and outwardly-facing wall  47 . Together, inwardly-facing wall  45 , connecting portion  48 , and outwardly-facing wall  43  define lobe receiving space  50 . Second dual inner seal  40  includes generally cylindrical hollows  62  and  64  which facilitate deformation of seal  42  upon establishment of an interlocking seal. 
     Turning again to  FIG. 2 , when both doors  18 ,  20  are in their respective closed positions, first sealing lobe  30  of first exterior seal  22  deflects such that lobe  30  is pressed against outer wall  116  to form an outer fluid-tight seal between doors  18  and  20 . Meanwhile, second sealing lobe  36  of second exterior seal  24  and second sealing lobe  32  of first exterior seal  22  mutually deform against one another, such that the gap between doors  18  and  20  is bridged by a fluid-tight seal engagement disposed just interior of exterior seal  22 . In this way, two sealing layers are established by the interaction of seals  22  and  24 : inner lobes  32 ,  36  deform against one another to form a first, inner seal within the gap between doors  18 ,  20 , while first sealing lobe  30  resiliently biases against wall  116  to form a second, redundant outer seal between the closed doors  18 ,  20 . 
     Inner seals  40 ,  42  form yet another multiple-engagement barrier to fluid and thermal transfer between cargo box  15  and the ambient environment. As door  18  moves towards door  20  during the transition from the open position to the closed position (e.g., along direction A as shown in  FIG. 3 ), first inner seal  42  abuts, and then slides across, second inner seal  40  causing mutual deformation thereof. When in the closed position shown in  FIG. 2 , outer lobe  46  of second inner seal  40  interfits within lobe receiving space  60  of first inner seal  42  and inner lobe  44  of first inner seal  42  interfits within receiving space  50  of second inner seal  40 . 
     This interfitting arrangement creates three mutual lobe-on-lobe deformations which act to create fluid tight sealing engagements between first inner seal  42  and second inner seal  40 : (1) inwardly-facing wall  55  abuts outwardly-facing wall  47 ; (2) inwardly-facing wall  45  abuts outwardly-facing wall  53 ; and (3) inwardly-facing wall  51  abuts outwardly-facing wall  43 . Further, generally cylindrical hollows  62 ,  64 ,  66 , and  68 , in cooperation with air pockets that form between a tip of inner lobe  54  and connecting portion  48  and between and tip of outer lobe  46  and connecting portion  58 , create a total of six air barriers in the gap between doors  18  and  20 . These six air barriers are serially disposed between the interior of cargo box  15  and the ambient environment, and each additional air barrier serves to further inhibit thermal transfer across the interfitted inner seals  40 ,  42  and thereby prevent thermal losses from within trailer  10  to the ambient environment. In addition, a sealed space between exterior seals  22 ,  24  and inner seals  40 ,  24  is formed, creating yet another air barrier. Elliptical hollows  33 ,  38  cooperate to form still another air barrier. Finally, sealing lobe  30  defines yet another sealed space exterior of seal  24  and outer wall  116  and interior of the inner surface of lobe  30 . 
     In the illustrated embodiments, the seals are installed in door frames that are secured to doors  18  and  20 . Referring to  FIGS. 2 and 3 , door frame  102  is attached to door  18  and door frame  104  is attached to door  20 , with each door frame extending the entire perimeter of each door to accommodate seals that seal the entirety of rectangular openings  19  (shown in  FIG. 1 ). For example, referring to  FIG. 3 , door frame  102  includes inner wall  108 , outer wall  106 , and three mounting openings  110 ,  112 , and  114  into which the mounting portions of the various seals may be installed (the installation process will be described further below). Specifically, mounting portion  26  of first exterior seal  22  fits into mounting opening  114  and mounting portions  67  and  69  of first dual inner seal  42  fit into mounting openings  110  and  112 , respectively. Likewise, for door frame  104 , mounting portion  34  of second exterior seal  24  fits into mounting opening  124  and mounting portions  63  and  65  of second dual inner seal  40  fit into mounting openings  120  and  122 , respectively. 
     Referring to  FIG. 2 , when doors  18  and  20  are in the closed position, mounting openings  110  and  112  and opposing mounting openings  120  and  122  are staggered such that the mounting openings  110 ,  112  on door frame  102  are closer to the exterior of doors  18  and  20  than the corresponding mounting openings  120 ,  122  of door frame  104 . This staggered arrangement facilitates the interfitting of first inner seal  42  and second inner seal  40  when doors  18  and  20  are in the closed position (described in detail above). Of course, alternatively, the mounting openings on door frame  104  could also be staggered closer to the exterior of doors  18  and  20  than the mounting openings on door frame  102 , as required or desired for a particular application. 
     2. Seal Installation 
     Referring to  FIGS. 2 and 3 , as noted above, door frames  102  and  104  facilitate the easy installation of first and second exterior seals  22  and  24  and first and second dual inner seals  42  and  40 . Each of seals  22 ,  24 ,  40  and  42  has one or two mounting portions that are sized to be secured tightly within mounting openings formed along each door frame, taking advantage of each seal&#39;s elasticity, resilience and flexibility. For example, referring to  FIG. 5 , a step of the installation process of first dual inner seal  42  is shown. First, a part of mounting portion  69  is inserted into mounting opening  112 . Second, by applying pressure to the space between connecting portion  58  and mounting portion  69  using tool  90 , the remaining part of mounting portion  69  can be deformed and wedged into mounting opening  112 . When fully received within opening  112 , sealing portion resiliently returns to its original shape and configuration, thereby conforming to the inner profile of opening  112  as shown in  FIG. 2 . 
     The above-described installation process can be used along the entire length and periphery of first dual inner seal  42  to fill the entire perimeter of either door  18  or  20 . This process can also be used on the similarly shaped mounting portions  67  of seal  42 , and on mounting portions  26 ,  34 ,  63  and  65  of other seals  22 ,  24  and  40  respectively. 
     3. Methods of Seal Production 
     In an exemplary embodiment, each of the seal portions is produced independently by extruding pliable material at an elevated temperature through an appropriately shaped die. A single continuous strip of extruded material may therefore be produced and cut to length for each of the three seal profiles shown in  FIGS. 2-5  and described above (it being understood that seals  40  and  42  have the same profile in the exemplary illustrated embodiment). A unique extrusion profile may be created for different size seals to span a given gap between doors  18  and  20 . 
     Four seal portions are then cut to appropriate lengths corresponding to each of the four sides of door  18  and/or door  20 . Respective ends of these four seal portions are then fused to one another to form the four seal portions into a single, unitary, monolithic truck door seal having a generally rectangular central opening  19  ( FIG. 1 ). This fusing process is repeated for the other seal profiles in the present seal arrangement, as well as for the other of doors  18 ,  20 . Methods of fusing the corners in accordance with the present disclosure are discussed in detail below. 
     As noted above, each seal may be made of a resilient, elastically deformable and/or compressible material. Such materials may include natural rubber, silicone, isoprene, ethylene propylene (“EPM”) or ethylene propylene diene monomer (“EPDM”) rubber, a mixture of cross-linked EPDM rubber and polypropylene, such as SANTOPRENE® (SANTOPRENE® is a registered trademark of the Exxon Mobil Corporation of Irving, Tex.), or any other suitable material. In an exemplary embodiment, the material used for the seals has good resistance to compression set, resists degradation from exposure to UV light and other environmental impacts, and remains pliable in cold temperatures. 
     In an exemplary embodiment of the present disclosure, such as the embodiments illustrated in  FIGS. 1-5 , the seal material is made from EPDM, which has been found exhibit the above-mentioned exemplary qualities for superior longevity in the environments normally encountered by shipping trailers. For example, normal use of a truck door seal made in accordance with the present disclosure may subject the seal to repeated deformations over time, such as by repeated opening and closing of the doors to which the seal is attached, or to vibrations and deformations resulting from movement of the vehicle with which the doors are associated. Forming the seal from a material highly resistant to compression set, such as EPDM, renders the seal well-suited for use in the potentially harsh service environments encountered in the shipping industry. Even after repeated deformations, the above-mentioned seal materials maintain their original shape and elasticity and are therefore able to maintain the desired sealing effect over time. In one exemplary embodiment, EPDM having a durometer of about 60 may be used. When the seals are monolithic as described herein, the durometer of the entirety of such seals is the same throughout respective seal cross sections. 
     Two exemplary methods of fusing the seal portion corners include fusing the seal portions at a miter cut and injection molding the seal corners. In the first method, two respective seals are miter cut at their edges at 45-degree angles. The miter-cut edges are abutted and heated in order to fuse the two seal portions to one another at a 90-degree angle. The heat fusing of the extrusion members may be effected in various ways including fusing of mitered edges and injection molding. 
     In the second method of fusing the seal portion corners, each seal portion may have regular or plain-cut ends, i.e., the plane of the cut surface may be transverse to the direction of extrusion. These cut ends may then be placed adjacent one another beneath an injection molding head and adjacent an injection-molding die, with a corner of the cuts touching or nearly touching. The void at the seal corner is then filled by injecting molten seal material into the injection-molding die, and allowing such molten rubber to contact and fuse to each seal end. 
     However the corners are fused, the seals form continuous and uninterrupted “bulbs” around the entire periphery of the seal. Further discussion of exemplary fusing processes which may be used with the present seal arrangements are presented in U.S. Pat. No. 8,839,564, entitled TRAILER DOOR SEAL, filed Jul. 28, 2011 and assigned to the present assignee, the entire disclosure of which is hereby expressly incorporated by reference herein. 
     While this invention has been described as having an exemplary design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.