Patent Publication Number: US-9416574-B2

Title: Lift-off type hinge

Description:
REFERENCE TO RELATED APPLICATION 
     This is a continuation-in-part of U.S. patent application Ser. No. 13/760,997 filed Feb. 6, 2013. 
    
    
     TECHNICAL FIELD 
     This invention relates generally to door hinges, and more particularly to 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. 
     A problem associated with these “lift-off” type hinges is that the hinge spring is designed to move the cam past the point of door closure to ensure a complete closing of the door, this may be referred to as an over-closure angle between the hinge strap and hinge flange. As a result of the over-closure of the earn when the door is taken off the hinge, the subsequent replacement of the door upon the hinge flange does not always result in the proper alignment of the hinge strap upon the hinge flange. This problem can result in the poor closure function of the hinge, the misalignment of the hinge components, and/or damage to the hinge. 
     Accordingly, there is a need in the art for a hinge that will allow for the door to be lifted off easily, which does not promote door sag, which allows small adjustments to the hinge, and which properly aligns the hinge components when disassembled and subsequently reassembled. 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 a hinge comprises a mounting flange assembly having a cam and a rotating cam follower configured to mate with the cam. The cam follower has an exterior surface and a longitudinally ending alignment groove extending inwardly fro the exterior surface. The hinge also has a strap assembly pivotally coupled to the mounting flange assembly. The strap assembly includes a strap having at least one strap mounting hole and a coupling end having a longitudinally extending channel therein configured to receive at least a portion of the mounting flange cam follower. The channel includes a longitudinally and inwardly extending alignment tongue configured to be received within the longitudinally extending alignment groove of the cam follower. With this construction, the proper alignment between the cam follower and the strap assembly may only occur when the alignment tongue aligns with and is received within the alignment groove. 
    
    
     
       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 top view of the anti-sag hinge of  FIG. 1 , shown in partial cross-section. 
         FIG. 3  is a perspective view of a portion of the anti-sag hinge of  FIG. 1 . 
         FIG. 4  is an exploded view of the anti-sag hinge of  FIG. 1 . 
         FIG. 5  is a cross-sectional view of a bushing of the anti-sag hinge of  FIG. 1 . 
         FIG. 6  is a perspective view of the cam follower of the anti-sag hinge of  FIG. 1 . 
         FIG. 7  is a perspective view of the spacer of the anti-sag hinge of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION 
     With reference next to the drawings, there is shown a lift-off type 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 metal mounting plate  16  having four mounting holes  17  therethrough adapted to receiving unshown mounting bolts or screws, and a metal low hinge flange  18  extending from the mounting plate  16 . As used throughout the entire disclosure herein, the terms sere and bolt are used interchangeably. The lower hinge flange  18  includes a cam recess  19  configured to receive a cam assembly which has an internally mounted cam  20  and cam follower  40  which enables the hinge to be a riser type hinge, although his is merely option of the present invention. The cam  20  includes a dual sloped camming surface  21 . The cam  20  and later described cam follower  40  are preferably made of a smooth, low-frictional plastic material such as nylon. The lower hinge flange  18  also includes a shoulder bolt hole  22  therethrough in which is mounted a shoulder bolt or rod  25 . 
     The strap assembly  15  includes a metal elongated 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 a coupling end  34  with a vertically extending octagonal channel  35  therethrough. The octagonal channel  35  includes a generally vertically extending alignment ridge or tongue  36  extending longitudinally along the channel  35  and a centrally positioned, horizontally oriented, annular ridge  37  which generally bisects the channel  35 . A cap  38  is pressed into and seals the top opening of the channel  35 . The cylindrical portion  32  also houses the elongated cam follower  40  having a lower cam follower portion  41  and an upper cam follower portion  42 . The lower cam follower portion  41  has an octagonal exterior surface  43  terminating at a circumferential ledge or shoulder  44  positioned to abut and bear against the centrally positioned annular ridge  37  of the coupling end  34 . It should be noted that the coupling end octagonal channel  35  is longitudinally symmetric about the centrally positioned annular ridge  37  so that the cam follower  40  may be positioned in either end, thereby making it reversible (either left hand or right hand door configurable) so that the cam follower may fit in the octagonal channel  35  from either open end. The lower cam follower portion  41  also has an interior surface  46  with a cam following surface  47  configured to mesh or mate with the cam camming surface  21 . The cam following surface  47  includes a low point or low point area  48  flanked on either side by symmetrical incline surfaces which terminate at a common dwell surface. The symmetry allows the cam follower to rise with rotation in either direction so that the hinge may be mounted to both right hand and left hand opening doors. The lower cam follower portion  41  also has a longitudinally extending slot or groove  53  configured to receive the coupling end alignment tongue  36 . The groove  53  has a camber  54  in the ledge  44  (cambered entrance) at its top end which aids in initially guiding the tongue  36  into the groove as the strap assembly is coupled with the mounting flange assembly  12  with the cam follower being inserted into the mounting end octagonal channel  35 . The groove  53  is aligned along the exterior surface directly opposite the low point  48 , so that the groove  53  extends into or corresponds to the longest portion of the camming surface to allow for the greatest degree of strength or minimizing the weakening of component due to the absence of material created by the groove  53 . 
     The upper cam follower portion  42  is generally cylindrical with a round exterior surface  55  and a round interior surface  56  defining an interior channel  57  commencing at an interior floor  58 . A bolt or rod hole  59  passes through the center of the cam follower in which resides the shoulder rod  25  so that the cam follower  40  may rotate or pivot about the shoulder rod and relative to the underlying cam  20 . 
     The strap assembly  15  also includes a compression spring  62  positioned concentrically about the shoulder rod  25  and within cam follower interior channel  56 . A bushing  63  and washer  64 , positioned on top of the bushing  63 , are also positioned concentrically about the shoulder rod  25  and within the cam follower interior channel  56 . The bushing  63  has a peripheral flange  65  with an annular bottom recess  66  configured to receive a topmost portion of the compression spring  62 , which enables the spring  62  to be maintained tightly in position while still allowing lateral room for the spring to expand during spring compression under load, i.e., with the spring under no load there is room between the spring and the interior surface  56  which allows the spring to laterally expand when it is vertically compressed and therefore laterally expanded under a load. The top of the shoulder rod  25  is blunted or deformed to prevent the removal of the washer  64  and thereby the bushing  63  mod spring  62 . The compression of the spring  62  biases the cam follower  40  to its lowermost position, which will correlate with the closed position of the refrigerator door or an over-closure position past the closed position of the refrigerator door, and a such the hinge shown in the drawings is a self-closing type hinge. 
     The strap  31  includes a large interior well or recess  68  having four elongated mounting hole  69 , an adjustment screw flange, holder or boss  70  having a screw hole or passageway  71  therein, an upper guide  72  and a lower guide  73 . The recess  68  is defined by the sidewalls  74  of the strap  31  which extend to the most outboard portion of the hinge, i.e., a peripheral sidewall  74  which extends outwardly from the underlying door so as to make initial contact with any structure colliding with or impacting upon the hinge. The adjustment screw boss passageway  71  preferably is U-shaped so as to have an open top configuration. 
     The strap  31  also includes a moveable adjustment bracket  77  mounted for lateral movement relative to the underlying strap  31 . The vertical movement of the adjustment bracket  77  is limited by the upper guide  72  and lower guide  73 . The adjustment bracket  77  also includes an adjustment screw mounting flange  78  having a threaded screw hole  79  therein in which is threadably mounted an adjustment screw  80 . The adjustment screw  80  has ahead  81 , a bearing flange  82 , a neck  83  extending between the head  81  and bearing flange  82 , and an externally threaded shaft  84  which is threaded into mounting flange screw hole  79 . A removable spacer  86  is removably mounted to the adjustment screw  80 . The spacer  86  has a U-shaped gripping portion  87  which is snap fitted onto a neck portion of the threaded shaft  84  between the bearing flange  82  and the adjustment bracket screw flange  78 . Lastly, the adjustment bracket  77  includes four mounting holes  88  extending therethrough and generally in alignment with strap elongated mounting holes  69 . A flexible bumper or cover  90  is configured to fit snugly into the top end of the strap recess  68  to protect and seal the interior of the strap assembly, the bumper may include tabs which fit within corresponding tab holes or grooves in the strap. 
     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 plate  16  is secured to the jamb by the use of screws (not shown) that extend through the mounting plate 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  88  of the strap assembly adjustment bracket  77  and through the four elongated mounting holes  69  of the strap  31 . The removable spacer  86  is initially positioned so that the adjustment bracket mounting holes  88  are aligned with the strap mounting holes  69 . Once the flange assembly mounting screws are secured and the strap assembly mounting screws are partially secured but not finally tightened, final adjustment of the adjustment bracket may occur to level the door. 
     To adjust the bracket, the removable spacer  86  is removed and the adjustment screw  80  is rotatably threaded into the threaded hole  79  of the screw adjustment flange  78  to cause relative movement between the adjustment bracket  77  and the underlying strap  31 . This relative movement causes the movement of the door relative to the stationary jamb, as the elongated holes  69  allow relative 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 of the strap  31 . 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. 
     The rotation of the adjustment screw  80  in one direction (clockwise) causes the threaded screw  80  to be threaded further into the screw flange  78  of the adjustment bracket  77 , thereby causing the adjustment bracket  77  to move towards the boss  70 . The rotation of the threaded screw  80  in this direction causes the screw head  81  to bear against the boss  70  to force the lateral movement. The rotation of the adjustment screw  80  in the other direction (counter-clockwise) causes the threaded screw  80  to be threaded further out of the adjustment bracket flange  78 , thereby causing the adjustment bracket  77  to move in a direction away from the boss  70 . The rotation of the threaded screw  80  in this direction causes the screw bearing flange  82  to bear against the boss  70  to force the lateral movement in a direction away from the boss  70 . As such, the bolt is allowed to rotate yet is prevented from moving laterally along the longitudinal axis of the bolt by the contact between the bolt and the boss due to the bolt head and bearing flange bearing upon the boss. 
     It should be understood that the present invention is an improvement over the prior art shown in U.S. Pat. No. 7,870,642 as the threaded portion in which the adjustment screw is threaded into resides in the removable adjustment plate. This allows the manufacturing of the threads in the mounting hole to occur in a simple manner, as oppose to the prior art which required the threading process to occur on the large, heavy flange of the strap itself, thus complicating the manufacturing process of the hinge and causing a great deal of problems if the threads were not properly formed. Furthermore, if the threads become stripped or damaged only the adjustment bracket needs to be replaced rather than the entire hinge strap. 
     It should also be understood that the open channel or passageway  71  of the boss allows for the case of positioning the adjustment bracket by simply dropping the adjustment screw neck  83  into the boss wherein the spacer is utilized to maintain the position of the adjustment screw. 
     It should be understood that the lower portion  41  of the cam follower is not required to be hexagonal in shape and may be of any shaped which aids in preventing relative rotation between the cam follower and its corresponding channel, i.e., it may be oval, any polygonal shape, or any other non-round shape. Preferably, the cam follower has regular polygon exterior configuration wherein all sides and angles are equal, such as the octagonal shape shown in the preferred embodiment. 
     It should be understood that the terms cam and cam follower may be used interchangeably, as each simply includes a sloping surface configured to ride upon the other&#39;s sloping surface. 
     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.