Patent Publication Number: US-7584523-B1

Title: Anti-sag hinge

Description:
TECHNICAL FIELD 
     This invention relates generally to door hinges, and more particularly to double shear type anti-sag hinges used for commercial refrigerator and freezer doors. 
     BACKGROUND OF INVENTION 
     Walk-in cold rooms, such as walk-in coolers, freezers, or other refrigerated environments, are common in various industries, including supermarkets and grocery stores, commercial kitchens, and other food service facilities. They typically have one or more access doors for entry and exit. 
     These doors are heavy and thus a common problem that may occur over time is door sag, which may cause the door not to open freely as it drags against the underlying floor or be properly locked or sealed as it does not fully close. The sag is caused by hinge wear, structural shifting due to temperature cycling, impacts, abuse, poor design of the door and frame, or the hinges shifting on the mounting screws. Sag is difficult to overcome without extensive repair work, such as the removal and remounting of the hinges or the replacement of the door and frame. For the replacement, adjustment or cleaning of the hinge the NSF prefers that the hinge be a “lift-off” type to allow the door and the enclosure to be cleaned by lifting it off the hinges and hosing down the door assembly. Most lift off hinges are of a cantilever style that includes a single shear system. Single shear system hinges however are prone to wear due to the forces exerted upon the cantilevered hinge. 
     Accordingly, there is a need in the art for a hinge that will allow for the door to be lifted off easily and which does not promote door sag. It is to the provision of such therefore that the present invention is primarily directed. 
     SUMMARY OF THE INVENTION 
     In a preferred form of the invention an anti-sag hinge comprises a flange assembly having a mounting flange, a lower hinge barrel and an upper hinge barrel. The upper hinge barrel is removable mounted to the mounting flange. The hinge also has a strap assembly pivotally coupled to the flange assembly. The strap assembly includes a strap and a cylinder portion removable coupled to the lower hinge barrel and the upper hinge barrel. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a front view of an anti-sag hinge embodying principles of the invention in a preferred form. 
         FIG. 2  is a front view of the anti-sag hinge of  FIG. 1 , shown with the covers removed. 
         FIG. 3  is a cross-sectional side view of the anti-sag hinge of  FIG. 1 . 
         FIG. 4  is a top view of the anti-sag hinge of  FIG. 1 . 
         FIG. 5  is a front view of the anti-sag hinge of  FIG. 1 , shown with the upper hinge barrel lifted from its mounted position to a removed position. 
     
    
    
     DETAILED DESCRIPTION 
     With reference next to the drawings, there is shown an anti-sag hinge  10  according to the present invention. The hinge  10  includes a mounting flange assembly  12  pivotally coupled to a strap assembly  15 . It is to be appreciated that the hinge  10  shown in the drawings is configured for use with a walk-in refrigerator or freezer door. The jamb and doors are well-known in the art and need not be disclosed further herein. It is to be further appreciated that the hinge  10 , either alone or in combination with another hinge in accordance with the present invention, support a door (not shown) in the usual manner. 
     The mounting flange assembly  12  includes a mounting flange  16  having four mounting holes  17  therethrough adapted, to receiving unshown mounting bolts or screws, a lower hinge barrel  18  extending from the mounting flange  16 , and a removably mated upper hinge barrel  19  extending from the mounting flange  16 . The upper and lower hinge barrels provide for a dual or double shear system (two positions wherein a shearing force is provided between the strap assembly and the flange assembly  12 ) that provides a stable connection between the strap assembly  15  and the flange assembly  12 . The lower hinge barrel  18  includes an internally mounted cam  21  which enables the hinge to be a riser type hinge, although this is merely an option of the present invention. The lower hinge barrel  18  also includes a shoulder bolt hole  22  therethrough. The upper hinge barrel  19  includes a dove-tail flange  23  and a shoulder bolt hole  24  therethrough which includes a countersunk hexagonal hole portion  25 . The dove-tail flange  23  is configured to removably mate with a tapered slot  26  extending from the top edge of the mounting flange  16 . The mounting flange assembly  12  also includes a removable upper flange cover  28  configured to cover the upper hinge barrel  19  and a removable lower flange cover  29  configured to cover the lower hinge barrel  18 . The covers  28  and  29  are provided for many reasons, including aesthetics and to meet the sanitary requirements employed in the industry as specified by the National Sanitation Foundation. 
     The strap assembly  15  includes a strap  31  extending from a cylinder portion  32 . The term cylinder portion  32  is meant to describe the enlarged casing located at the end of the strap and the encased bearings, spring, and cam described in more detail hereinafter. The term cylinder portion is not intended to be limited to a cylinder shape, as this portion or parts of this portion may be of many known shapes and are not necessarily cylindrical in shape. The cylindrical portion  32  includes an upper strap bearing  33 , a lower strap bearing  34 , a thrust washer  35 , a spring  36  mounted between the lower strap bearing  34  and the thrust washer  35 , and a cam follower  37  configured to mate with cam  21 . A shoulder bolt  38  extends through the upper hinge barrel mounting bolt hole  24 , the upper strap bearing  33 , the thrust washer  35 , the spring  36 , the lower strap bearing  34 , the cam follower  37 , the cam  21 , and through the lower hinge barrel mounting bolt hole  22 . A hex nut  39  is threaded onto the lower end of the shoulder bolt  38  while the head portion  40  of the shoulder bolt is configured to fit snugly within the hexagonal hole portion  25 . 
     The strap  31  includes four elongated mounting holes  42 , a screw adjustment flange  43  having a threaded screw hole  44  therein, an end guide  45 , an upper guide  46  and a lower guide  47 . The strap  31  also includes a moveable adjustment bracket  50  mounted for lateral movement relative to the underlying strap  31 . The movement of the adjustment bracket  50  is limited by the end guide  45 , upper guide  46  and lower guide  47 , which each reside within notches  51  extending inwardly from the peripheral edge of the adjustment bracket  50 . The adjustment bracket  50  also includes an adjustment screw mounting flange  52  and an adjustment screw  53  extending through an adjustment bracket mounting hole  54  and threaded into screw adjustment flange screw hole  44 . A retaining ring  55  is fitted upon the mounting screw  53  to secure its position. Lastly, the adjustment bracket  50  includes four mounting holes  56  extending therethrough and generally in alignment with strap elongated mounting holes  42 . Again, the strap assembly also includes a cover  57  configured to fit snugly over the strap  31  and cylindrical portion  32  to protect and seal the interior of the strap assembly. 
     In use, the hinge  10  is mounted to the refrigerator or freezer door in the conventional manner as is well known in the art. The mounting flange  16  is secured to the jamb by the use of screws (not shown) that extend through the mounting flange mounting holes  17  and into the jamb. A conventional walk-in refrigerator or freezer door is similarly secured to the hinge  10  by four screws (not shown) that extend through the four mounting holes  17  of the strap assembly adjustment bracket  50  and through the four elongated mounting holes  42  of the strap  31 . 
     Next, the adjustment screw  53  is rotatably threaded into the threaded hole  44  of the screw adjustment flange  43  to cause relative movement between the adjustment bracket  50  and the underlying strap  31 . This relative movement causes the movement of the door relative to the stationary jamb, as the elongated holes  42  allow movement of mounting screws and adjustment bracket. The movement of the door enables the door to be properly aligned. The mounting screws are then fully tightened into the door to prevent further movement of the strap. Moreover, should the door sag over time, the mounting screws are slightly loosened and the adjustment screw is merely threaded to once again cause movement of the door to a properly aligned position, as previously described. 
     To remove the door from the jamb, the covers  28 ,  29  and  57  are removed. The hex nut  39  is then unthreaded from the shoulder bolt  38  and the shoulder bolt  38  is lifted and removed. Next, the upper hinge barrel  19  is lifted so that the dove-tail flange  23  is slides upwardly and is removed from the tapered slot  26 , as shown in  FIG. 5 . With the upper hinge barrel  19  disengaged from the upper strap bearing  33 , the strap assembly  15  may be raised vertically from the flange assembly  12  thereby removing the door from the jamb. As such, it should be understood that the hinge of the present invention has double shear capabilities or construction, yet it is configured to enable one to lift the door from the jamb. 
     Thus, the present invention fulfills the need in the art for an apparatus and method for providing a double shear hinge that enables a door to be lifted from and removed from a door jamb. This need is fulfilled by providing an anti-sag hinge for commercial walk-in refrigerator or freezer doors that includes a removably upper hinge barrel. 
     It should be understood that the upper hinge barrel may be designed to be removed from the mounting flange in a number of alternative manners, such as with mounting screws, coupling means, locking means, or other similar types of engagement therebetween. 
     While this invention has been described in detail with particular reference to the preferred embodiments thereof and the best mode of practicing same, it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described herein above and as set forth in the appended claims.