Patent Publication Number: US-11391074-B2

Title: Door hinge and storage unit including such a door hinge

Description:
This application claims the benefit of priority under 35 U.S.C. § 119(e)(1) of U.S. Provisional Application Ser. No. 62/680,414, filed Jun. 4, 2018, the entire contents of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention is directed to a door hinge and a storage unit, such as a refrigerator, that includes such a door hinge. 
     BACKGROUND OF THE INVENTION 
     A common goal in kitchens is to have storage units blend in with each other as much as possible. In the case of a storage unit being a kitchen appliance, such as a refrigerator, there are a number of possible modes for installation into a kitchen setting. One mode is to install a built-in refrigerator. When the cabinetry is constructed, a housing/space is defined that allows a refrigerator to be moved into the housing/space. The housing/space is dimensioned such that the sides of the refrigerator sit flush with the cabinetry that defines the housing/space. The top portion of the front of the refrigerator has vents that allows the compressor to vent therethrough. The exterior of the door of the refrigerator that faces into the kitchen area is not paneled so as to match the panel design of the cabinetry. In a closed position, the door is not flush with the adjacent cabinetry and extends past the cabinetry toward the interior of the kitchen. 
     A second mode of installation of a refrigerator is the installation of an overlay refrigerator. An overlay refrigerator is a built-in refrigerator wherein the exterior of the door facing the interior of the kitchen is designed to be fitted with a panel to match the cabinet design. With the panel attached and the door in the closed position, the front of the door facing into the interior of the kitchen protrudes past the cabinetry toward the interior of the kitchen. 
     A third mode of installation of a refrigerator is the installation of an integrated refrigerator. An integrated refrigerator is a built-in refrigerator wherein when installed within the space/housing defined by the cabinetry, the refrigerator looks identical to the cabinetry. In other words, the refrigerator is camouflaged so that it not obvious where the refrigerator is located when the door of the refrigerator is closed. To help accomplish the camouflaged effect, the integrated refrigerator does not have compressor vents that are visible and it has an inset door that matches the pattern of the cabinetry. Furthermore, when the door is closed, it is flush with the adjacent cabinetry. 
     In the case of an integrated refrigerator, it is a requirement that the hinge of the door operates so that the door opens outward from the refrigerator cabinet. This requires that the door must pivot and the hinge positions the door such that the door remains clear of the adjacent cabinetry. This is schematically shown in  FIG. 1 , wherein the door  10  has been rotated by an angle θ with respect to the front edge  12  of the refrigerator  14  to an open position. In addition, a side edge  16  of the door  10  can be positioned past the front edge  12  so as to be spaced from the adjacent cabinetry  18 . 
     Issues that may occur with integrated refrigerators are that the angle θ may be mechanically limited by the internal structure of the hinge used. In addition, the hinge may pitch a portion of the door  10  inward into the interior of the refrigerator cabinet. The possibility of having the door  10  positioned within the interior of the refrigerator  14  means that accommodations must be made within the interior so as to accept entrance of the portion of the door  10 . Such accommodations entail removing storage capacity, such as in the form of shelving or drawers, in the area where the door  10  would enter into the interior of the refrigerator  14 . 
     It is an object of the present invention to increase the amount of space within the interior of an integrated refrigerator. 
     Another object of the present invention is to increase the angular range of a hinge used for an integrated refrigerator. 
     SUMMARY OF THE INVENTION 
     One aspect of the present invention regards a hinge for a door of a storage unit, the hinge including a first bracket and a second bracket. The hinge further including a linking mechanism for coupling the second bracket to the first bracket so that the second bracket is able to translate and rotate relative to the first bracket, wherein a maximum amount of rotation of the second bracket relative to the first bracket is not determined solely by operation of the linking mechanism. 
     A second aspect of the present invention regards a storage unit including a housing that defines a cavity into which items can be stored, wherein the cavity has an opening. The storage unit further including a door that moves from a first position that blocks access to the opening and the cavity to a second position that allows access to the cavity via the opening. A hinge is attached to the housing and the door, wherein the hinge includes a first bracket attached to the housing and a second bracket attached to the door. The hinge further including a linking mechanism for coupling the second bracket to the first bracket so that the second bracket is able to translate and rotate relative to the first bracket, wherein a maximum amount of rotation of the second bracket relative to the first bracket is not determined solely by operation of the linking mechanism. 
     A third aspect of the present invention regards a storage system that includes a first storage unit that has a first housing that includes a first vertical side and wherein the first housing defines a first cavity into which first items can be stored, wherein the first cavity has a first opening. The first storage unit further includes a first door that moves from a first position that blocks access to the first opening and the first cavity to a second position that allows access to the first cavity via the first opening. The storage system includes a second storage unit that is adjacent to the first storage unit, wherein the second storage unit includes a second housing that has a second vertical side that is substantially parallel to and adjacent to the first vertical side. The second housing defines a second cavity into which second items can be stored, wherein the second cavity has a second opening. The second storage system includes a second door that moves from a third position that blocks access to the second opening and the second cavity to a fourth position that allows access to the second cavity via the second opening. The second storage unit also includes a hinge attached to the second housing and the second door, wherein the hinge includes a first bracket attached to the second housing and a second bracket attached to the second door and a linking mechanism for coupling the second bracket to the first bracket. The coupling is such that the second bracket is able to translate and rotate relative to the first bracket, wherein a maximum amount of rotation of the second bracket relative to the first bracket is not determined solely by operation of the linking mechanism. 
     A fourth aspect of the present invention regards a method of repairing a storage unit that includes a pivotable door. The method includes using a first element to aid in pivoting the door to a position, wherein the first element has a predetermined threshold of stress such that when the first element encounters a stress above the predetermined threshold of stress there will be a visible indication thereof. The method further includes observing that the visible indication has occurred, which is an indication that the door has encountered an overload situation. The method also includes replacing the first element with a second element that is identical to the first element, which also has the predetermined threshold of stress such that when the second element encounters a stress above the predetermined threshold of stress there will be a visible indication thereof. 
     A fifth aspect of the present invention regards a hinge for a door of a storage unit, wherein the hinge includes a first bracket, a second bracket, and a linking mechanism for coupling the second bracket to the first bracket so that the second bracket is able to translate and rotate relative to the first bracket. The hinge further includes an adjustable biasing mechanism that is coupled to the linking mechanism and which adjusts a load applied to the linking mechanism so as to move the first bracket in a particular direction. 
     A sixth aspect of the present invention regards a storage unit that includes a housing that defines a cavity into which items can be stored, wherein the cavity has an opening. The storage unit includes a door that moves from a first position that blocks access to the opening and the cavity to a second position that allows access to the cavity via the opening. The storage unit further includes a hinge attached to the housing and the door. The hinge includes a first bracket attached to the housing, a second bracket attached to the door, and a linking mechanism for coupling the second bracket to the first bracket so that the second bracket is able to translate and rotate relative to the first bracket. The hinge further includes an adjustable biasing mechanism that is coupled to the linking mechanism and which adjusts a load applied to the linking mechanism so as to bias the door toward the housing. 
     A seventh aspect of the present invention regards a storage system that includes a first storage unit that includes a first vertical side and wherein the first housing defines a first cavity into which first items can be stored, wherein the first cavity has a first opening. The first storage unit includes a first door that moves from a first position that blocks access to the first opening and the first cavity to a second position that allows access to the first cavity via the first opening. The storage system also includes a second storage unit that is adjacent to the first storage unit, where the second storage unit includes a second housing that has a second vertical side that is substantially parallel to and adjacent to the first vertical side, the second housing defines a second cavity into which second items can be stored, wherein the second cavity has a second opening. The second storage includes a second door that moves from a third position that blocks access to the second opening and the second cavity to a fourth position that allows access to the second cavity via the second opening. A hinge is attached to the second housing and the second door, the hinge including a first bracket attached to the second housing and a second bracket attached to the second door. The hinge further includes a linking mechanism for coupling the second bracket to the first bracket so that the second bracket is able to translate and rotate relative to the first bracket. The hinge also includes an adjustable biasing mechanism that is coupled to the linking mechanism and which adjusts a load applied to the linking mechanism so as to bias the second door toward the second housing. 
     One or more aspects of the present invention provide the advantage of increasing the amount of space within the interior of a storage unit, such as an integrated refrigerator. 
     One or more aspects of the present invention provide the advantage of increasing the angular range of a hinge used for a door of a storage unit, such as an integrated refrigerator. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The various features, advantages and other uses of the present apparatus will become more apparent by referring to the following detailed description and drawing in which: 
         FIG. 1  is a top view of a known orientation of a door of a refrigerator with respect to adjacent cabinetry, showing the door in an open position; 
         FIG. 2  is a perspective view of an embodiment of a storage system that includes an embodiment of a refrigerator in accordance with the present invention; 
         FIG. 3  is a perspective view of the refrigerator of  FIG. 2  when the door is in an open position in accordance with the present invention; 
         FIG. 4A  is a top perspective view of an embodiment of a hinge in a retracted position to be used with the refrigerator of  FIGS. 2-3  in accordance with the present invention; 
         FIGS. 4B-D  show possible orientations of the hinge of  FIG. 4A  as the hinge moves toward a fully opened position; 
         FIG. 4E  shows a front view of the hinge of  FIG. 4A  when oriented at the position shown in  FIG. 4D ; 
         FIG. 5  shows a perspective, exploded view of the hinge of  FIG. 4A ; 
         FIG. 6A  shows a top, perspective view of an embodiment of a support bracket to be used with the hinge of  FIGS. 4A-E  in accordance with the present invention; 
         FIG. 6B  shows a bottom, perspective view of the support bracket of  FIG. 6A ; 
         FIG. 7A  shows a top, right, perspective view of an embodiment of a support bracket to be used with the hinge of  FIGS. 4A-E  in accordance with the present invention; 
         FIG. 7B  shows a top, left, perspective view of the support bracket of  FIG. 7A ; 
         FIG. 8  shows an enlarged, interior view of an embodiment of a support bracket of the hinge shown in  FIGS. 4A-E ,  5 ,  6 A-B, and  7 A-B in accordance with the present invention; 
         FIG. 9A  shows an embodiment of a bias adjustment mechanism at a first orientation to be used with the support bracket of  FIGS. 6A-6B  in accordance with the present invention; 
         FIG. 9B  shows the bias adjustment mechanism of  FIG. 9A  at a second orientation; 
         FIGS. 10A-E  show various stages of the opening of an embodiment of a door of the refrigerator of  FIG. 3  using the hinge of  FIGS. 4A-E  and  5  a mirror image of the hinge of  FIGS. 4A-E  and  5  in accordance with the present invention; 
         FIG. 11A  shows a first state of an embodiment of a door switch when the door of the refrigerator of  FIG. 3  is in an open position; 
         FIG. 11B  shows a second state of the door switch of  FIG. 11A  when the door of the refrigerator of  FIG. 3  is in a closed position; 
         FIGS. 12A-C  show various orientations of embodiments of the load bearing arm and the return arm used in the hinge of  FIGS. 4A-E  in accordance with the present invention; and 
         FIGS. 13A-D  show various orientations of an embodiment of the stop mechanism used in the hinge of  FIGS. 4A-E  in accordance with the present invention; 
     
    
    
     DETAILED DESCRIPTION 
     As shown in the exemplary drawing figures, an embodiment of an integrated refrigerator is shown, wherein like elements are denoted by like numerals. 
       FIG. 2  shows an embodiment of a storage system  100  that is installed in a kitchen of a residence. The storage system  100  includes multiple storage units  102   a - b . Each storage unit  102   a - b  has a housing (not shown) that defines a cavity with an opening that faces the interior of the kitchen. Examples of such storage units  102   a - b  are known cabinetry, wherein the structure of the housing can vary from storage unit to storage unit depending on its position and the particular items which are to be stored within the cabinetry. For example, each opening can include different configurations of drawers and/or shelves for storage of various items. One or more of the storage units  102   a - b  includes a door  104  that is attached to the corresponding housing, wherein the door  104  moves from a first position that blocks access to the opening to a second position that allows access to the opening and cavity associated with the storage unit. 
     The storage system  100  is an integrated storage system in that when the doors  104  are in the closed position, they are flush with each other so that doors blend with each other. 
     One of the storage units of the storage system  100  is an integrated refrigerator  106 . As shown in  FIGS. 2-3 , the refrigerator  106  has a housing  108  that is positioned between two other storage units  102   a  and  102   b . The housing  108  includes a left vertical side  110 , a right vertical side  112  and a top  114  that is integrally attached to the sides  110  and  112 . An interior liner  116  is attached within the housing  108  and defines a cavity  118  that includes several shelves  120  and drawers  122 . 
     The refrigerator  106  includes an inset door  124  that is attached to the housing  108  in a manner to be described hereinafter. As shown in  FIG. 3 , an interior side  126  of the door  124  includes shelving  128 . The door  124  further includes an exterior side  130  that matches the pattern of the exterior sides of the doors  104  of the other storage units  102   a  and  102   b.    
     A pair of hinges  200  and  202  are attached to the top and bottom left or right corners of the door  124  and the housing  108 . For the sake of brevity, the top hinge  202  to be attached to the top right corners of the door  124  and housing  108  will be discussed hereafter with the understanding that the bottom hinge  200  to be attached to the bottom right corners of the door  124  and housing has a similar structure, attachment scheme, and operation as will be explained later. Note that the directional terms “right” and “left” used throughout this description are defined with respect to an observer that is facing the exterior side  130  of the door  124  when the door  124  is in a closed position. Also, note that in the case where the hinges  200  and  202  are to be attached to the top and bottom left corners of the door  124  and housing  108 , the hinge  202  is attached to the top corners and the hinge  200  is attached to the bottom corners in a manner similar to that described below. 
       FIGS. 4A-E ,  5 ,  6 A-B and  7 A-B show an embodiment of the top hinge  202 . The top hinge  202  includes a support bracket  204  that is attached to a top portion of the housing  108  so that a right edge  206  of an I-shaped bottom plate  208  is positioned approximately 3.85 inches from the right vertical wall  112  of the housing  108 . At each of the left and right edges of the bottom plate  208  are a pair of openings  209 . The support bracket  204  is made of a durable material, such as steel. As shown in  FIGS. 5 and 6A -B, a pair of identical L-shaped side pieces  210 ,  212  are positioned within notches formed in the side of the bottom plate  208  and attached to the bottom plate  208  in a well-known manner, such as welding. Alternatively, the bottom plate  208  and the side pieces  210 ,  212  can be formed from the same piece of material. To provide further strengthening, a cross-piece  214  is positioned within notches formed in the right ends of the side pieces  210 ,  212  and attached to the side pieces  210 ,  212  in a well-known manner, such as welding. 
     As shown in  FIGS. 4A-E ,  5  and  7 A-B, the top hinge  202  includes a mounting bracket  216 . The mounting bracket  216  is made of a durable material that is the same used for the support bracket  204 . Mounting bracket  216  has a rectangular-like exterior face  218  with an arcuate ear  220  integrally attached at an angle of approximately 90 degrees. The exterior face  218  defines a slot  222 . Also integrally formed with the exterior face  218  is a mounting face  224  that faces toward the floor when the hinge  202  is attached to the door  124 . The mounting face  224  is at an angle of approximately 90 degrees relative to the exterior face  218  and has multiple holes  226 . The mounting bracket  216  is attached to a top rectangular-like horizontal area at the top, right corner of the inner side  126  of the door  124  that extends from the right edge of the door  124  by approximately seven inches. Attachment is achieved by aligning the mounting face  224  onto the bottom rectangular-like area and attaching the mounting bracket  216  thereto by having bolts  227  inserted through the holes  226  and engage aligned threaded openings (not shown) formed in the top rectangular-like horizontal area. 
     As shown in  FIGS. 4A-E ,  5  and  7 A-B, the mounting bracket  216  has an interior flange  228  integrally attached to the exterior face  218  that is opposite to, parallel to, and has a shape that is almost identical to that of arcuate ear  220 . Attachment is achieved by inserting a bottom portion of the interior flange  228  into slot  222  formed in the exterior face  218  and then welding the interior flange  228  to the exterior face  218 . As shown in  FIG. 4E , the flange  228  is positioned closer to the arcuate ear  220  than the mounting face  224 . 
     As shown in  FIGS. 4A-E  and  5 , the mounting bracket  216  is coupled to the support bracket  204  by a linking mechanism  230 . The coupling is such that the mounting bracket  216  is able to translate and rotate relative to the support bracket  204 , wherein a maximum amount of rotation of the mounting bracket  216  relative to the support bracket  204  is not determined solely by operation of the linking mechanism  230 . 
     As shown in  FIGS. 4A-E  and  5 , the linking mechanism  230  includes a load bearing arm  232  and a return arm  234 . In the case of the load bearing arm  232 , a cylindrical-like end  236  is positioned between the side pieces  210 ,  212  of the support bracket  204  so that the openings  238  at each end of the end  236  are aligned with the openings  240 ,  242  of the side pieces  210 ,  212 . Note that each of the openings  238  includes a bushing  244  press-fit into the opening  238 . Next, a solid metal pin  243  is inserted through the aligned bushings  244  and openings  240 ,  242  and  238  so that the pin  243  is positioned therein and attached to the load bearing arm  232 . Note that pin  243  is attached, because ends  245  of pin  243  expand and form a permanent compressive fit with the bushings  244 . While pin  243  is permanently attached to the bushings  244  and the end  236 , ends of the pin  243  are positioned within openings  240  and  242  so that the load bearing arm  232  is able to freely rotate about the pin  243  and an axis defined along the longitudinal axis of opening  238 . 
     Attachment of the return arm  234  to the support bracket  204  will now be described. The return arm  234  is coupled to a biasing mechanism that includes a helical spring  246  that biases the return arm  234  so that it tends to move mounting bracket  216  and the door  124  in a return direction to the closed position shown in  FIG. 4A . 
     As shown in  FIGS. 5, 8 and 9A -B, a free end  248  of the helical spring  246  is supported on the interior surface  250  of the side piece  212  and abuts the interior surface of the cross-piece  214 . The preload force of the spring  246  holds the free end  248  against the cross-piece  214 . The longitudinal axis of the helical spring  246  is aligned with an opening  252  of the side piece  212 . The other free end  254  of the spring  246  is inserted into a hole formed in the underside of the return arm  234  so as to be attached to the return arm  234  as shown in  FIG. 8 . When the helical spring  246  is in place, a spacing cylinder  256  is placed within the opening defined by the spring  246  as shown in  FIG. 8 . 
     As shown in  FIGS. 9A-B , the load supplied by the spring  246  to the return arm  234  can be adjusted. As shown in  FIG. 9A , the previously mentioned biasing mechanism includes a screw  500  that is inserted into a threaded opening  502  of the cross-piece  214 . To adjust the load supplied by the spring  246 , the screw  500  is rotated so that it extends through the opening  502 , engages the free end  248  of the helical spring  246 , and moves the free end  248  to a desired position spaced from the cross-piece  214 . Such movement adjusts the amount of compression of the spring  246  and so the amount of load generated by the spring  246  is adjusted. Moving the free end  248  further away from the cross-piece  214  via screw  500  will lead to an increase in the load supplied by the spring  246 . Moving the free end  248  closer to the cross-piece  214  via screw will lead to a decrease in the load supplied by the spring  246 . 
     With the spacing cylinder  256  in position, an end  258  of the return arm  234  is positioned between the top surface of the cylinder  256  and the side piece  210  of the support bracket  204 . Within both ends of opening  260  of the end  258  are bushings  268  that are press-fit into the opening  260 . As a result of the positioning of the return arm  234 , the opening  260  of the end  258  and the openings of the attached bushings  268  are aligned with the opening  262  of the side piece  210 . Next, a metal pin  264  is inserted through the openings  262 ,  260 , the openings of the bushings  268 , a cylindrical opening  266  of the cylinder  256  and the opening  252  of the side piece  212  so that the pin  264  is positioned therein and attached to the return arm  234 . Note that pin  264  is so attached, because ends  270  of pin  264  expand and form a permanent compressive fit with the bushings  268 . While pin  264  is permanently attached to the bushings  268  and the end  258  of the return arm  234 , ends of the pin  264  are positioned within the openings  252  and  262  so that the return arm  234  is able to freely rotate about the pin  264  and an axis defined along the longitudinal axis of opening  260 . 
     Attachment of the load bearing arm  232  and the return arm  234  to the mounting bracket  216  will now be discussed. Regarding attachment of the load bearing arm  232  to the mounting bracket  216 , the load bearing arm  232  has another cylindrical-like end  272  that is positioned between the interior flange  228  and the mounting face  224  of the mounting bracket  216  so that the opening  274  is aligned with the aligned openings (not shown) of the mounting face  224  and the interior flange  228  and an aligned opening  276  of the arcuate ear  220 . Note that each of the openings  274  includes a bushing  280  press-fit into the opening  274 . Next, a solid metal pin  278  is inserted through the aligned bushings  280  and openings  274 ,  276  and the aligned openings of the mounting face  224  and the interior flange  228  so that the pin  278  is positioned therein and attached to the load bearing arm  232 . Note that pin  278  is so attached, because ends  282  of pin  278  expand and form a permanent compressive fit with the bushings  280 . While pin  278  is permanently attached to the bushings  280  and the end  272  of the load bearing arm  232 , ends  282  of the pin  278  are positioned within openings  276  and the aligned opening (not shown) of the mounting face  224  so that the load bearing arm  232  is able to freely rotate about the pin  278  and an axis defined along the longitudinal axis of the opening  274 . 
     Regarding attachment of the return arm  234  to the mounting bracket  216 , the return arm  234  has another end  284  that is positioned between the interior flange  228  and the arcuate ear  220  of the mounting bracket  216 . Note that each of the openings  286  of the end  24  includes a bushing  292  press-fit into the opening  286 . When the end  284  is positioned between interior flange  22  and arcuate ear  220 , the opening  286  of the end  284  is aligned with the aligned opening (not shown) of the interior flange  228  and an aligned opening  288  of the arcuate ear  220 . Next, a solid metal pin  290  is inserted through the aligned bushings  292 , the openings  286 ,  288  and the aligned opening of the interior flange  228  so that the pin  290  is positioned therein and attached to the return arm  234 . Note that pin  290  is so attached, because ends  294  of pin  290  expand and form a permanent compressive fit with the bushings  292 . While pin  290  is permanently attached to the bushings  292  and the end  24  of the return arm  234 , ends  294  of the pin  290  are positioned within openings  288  and the aligned opening (not shown) of the interior flange  228  so that the return arm  234  is able to freely rotate about the pin  290  and an axis defined along the longitudinal axis of the opening  286 . 
     As described previously and shown in  FIGS. 4A-E , the attached load bearing arm  232  and the return arm  234  define parallel paths of movement so that during any instant of time of operation of the linking mechanism  230 , the load bearing arm  232  defines a first path of movement and the return arm  234  defines a second path of movement that does not intersect the first path of movement. Thus, the maximum angle of rotation between the mounting bracket  216  and the support bracket  204  is not determined by a direct interaction between the load bearing arm  232  and the return arm  234 . 
     In order to limit the value of the maximum angle of rotation between the mounting bracket  216  and the support bracket  204 , a stop mechanism  294  is employed that interacts with the linking mechanism so as to determine the maximum amount of rotation of the mounting bracket  216  relative to the support bracket  204 . As shown in  FIGS. 4A-E  and  5 , the stop mechanism  294  includes a lever  296  that has an end  298  that is inserted into a slot  300  formed in the return arm  234 . The end  298  is rotatably attached to the return arm  234  by a pin  302  inserted into openings  304  of the return arm  234  and an opening  306  of the lever  296 . A second lever  308  of the stop mechanism  294  that has an end  310  that is inserted into the space formed between the interior flange  228  and the arcuate ear  220 . The end  310  is rotatably attached to the mounting bracket  216  by a pin  312  inserted into an opening  314  of arcuate ear  220  and an opening  316  of the lever  308 . A pin  318  is inserted into aligned openings  320 ,  322  of the levers  296  and  308  so that the levers can rotate relative to one another. 
     Note that a portion of the stop mechanism  294  is positioned within an indentation  324  formed in the load bearing arm  232 . In addition, the lever  296  has a stop surface  326  and the lever  310  has an engagement surface  328  which interact with one another when a maximum amount of rotation of said mounting bracket  216  relative to the support bracket  204  is achieved. For example, the maximum amount of rotation of the mounting bracket  216  relative to the loading bearing arm  232  can range from 0 to 130 degrees. In addition, the maximum amount of rotation of the mounting bracket  204  relative to a plane containing bottom plate  208  of support hinge  204  when attached to the housing  108  of the refrigerator  106  can range from −0.5 to 110 degrees. 
     With the above description of the top hinge  202  to be attached to the top right corners of the door  124  and housing  108  in mind, the operation of bottom hinge  200  can be readily understood by the following discussion of the movement of the top hinge  202  when attached to the top right corners of the door  124  as shown in  FIGS. 10A-E . Note that the bottom hinge  200  is essentially a mirror image of the top hinge  202  with respect to horizontal plane that bisects a vertical line drawn from the top hinge  202  to the bottom hinge  200 . One difference between the top hinge  202  and the bottom hinge  200  is that the top hinge  202  can include a door switch  400  that indicates whether or not the door  124  is at an open or closed position. As shown in  FIGS. 5 and 6 , the door switch  400  is attached to the side piece  210  by having screws  402  inserted through washers  406  and engage aligned openings of a housing  404  of the switch  400  and the side piece  210 . As shown in  FIG. 8 , a roller lever  404  of the switch  400  extends toward and contacts the return arm  234 . At the closed position of the door  124 , the return arm roller lever  404  makes contact with a side wall of the return arm  234 , which causes a circuit  504  to be opened as shown in  FIG. 11B . The opening of the circuit  504  will alert a controller (not shown) that the door is closed and results in various systems controlled by the controller to be either operated or stopped. When the door is positioned away from the closed position of  FIG. 11B , the roller lever  404  will no longer contact the return arm  234 , which results in the circuit  504  being closed as shown in  FIG. 11A . The closing of the circuit alerts the controller that the door is opened and results in various systems controlled by the controller to be either operated or stopped. In the movement to be described with respect to the top hinge  202 , the bottom hinge  200  will simultaneously mirror such movement. 
     As shown in  FIG. 10A , the top hinge  202  is fully retracted so that the door  124  of the refrigerator  106  is in a closed position. In  FIG. 10B , the door  124  is opened further, wherein the stop mechanism  294  just starts to appear.  FIGS. 10C-10D  show further opening of the door  124 .  FIG. 10E  shows the door  124  when fully opened. During the opening process the door is pitched outward while it rotates over center. Note that throughout the whole opening process the door is simultaneously rotated and translated away from the housing  108  of the refrigerator. Furthermore, the hinge  200  and the door  124  never contact the adjoining storage unit  102   a  during the entire opening process. As an additional property of the closing and opening operation, when the door  124  is opened so that door defines an angle of 90 degrees with respect to its starting position, the cavity  118  of the refrigerator  106  is not blocked by the door  124  since the door  124  is moved laterally away from the side wall of the refrigerator  106 . Closing of the door  124  involves a reversal of the opening process mentioned previously. 
     During the above described motion of the door  124 , note that the load bearing arm  232  carries a substantial portion of the load of the door  124  while the return arm  234  performs the positioning of the door  124 . In addition, when the door stop is acted upon, the door stop withstands a tensile force that is transferred from exterior face  218  to return arm  234 . 
     During the above described movement of the door  124  from the closed position to an open position and back again, the load bearing arm and return arm of each hinge  200 ,  202  move in parallel paths that do not intersect one another. This non-interaction allows for an increase in the maximum radial opening angle of the hinges  200 ,  202 . This mitigates additional stress in addition to cyclic loading from normal service on the load bearing arm  232 . However, as shown in  FIGS. 12A-C , the ends of the loading arm  232  and the return arm  234  that are attached to the mounting bracket  216  have different positions in the x and y directions shown in the drawings. Thus, the pivot point of the return arm  234  with respect to the mounting bracket  216  is able to move past the load bearing arm  232  during the opening process. One thing to keep in mind during the opening process is that the return arm  234  is biased, via spring  246 , for the initial portion of the opening process so as to return the door  124  to the closed position if left unattended. As the door  124  is opened, a transition or over-center point is reached approximately when the levers  296  and  310  of the stop mechanism define an angle β (see  FIGS. 13A-D ) that has a value of almost 90 degrees right angles to each other. Further opening of the door  124  causes the angle β to further increase and it results in the door  124  not returning to the closed position if left unattended past the transition point. Thus, the hinges and door define a bi-stable system that has the equilibrium states of the door returning to a closed position or the door remaining at an open position. 
     Note that while loading arm  232  and return arm  234  move during the opening and closing processes, the stop mechanism  294  is also moving as shown in  FIGS. 13A-13D , wherein the maximum amount of opening of the door  124  occurs when stop surface  326  contacts engagement surface  328  of stop mechanism  294  so that further movement between the levers  296  and  310  during the opening operation is prevented. When the levers  296  and  310  can no longer move during the opening operation that results in the load bearing arm  232  and the return arm  234  from further opening the door  124 . 
     During usage, there can occur instances when a user “slams” the door open by quickly pulling the door and releasing the handle when the door is still swinging through its arc at nonzero velocity. This extreme case of overloading of the door is an unintended use of the door, where the force applied to the door is likely to otherwise damage the refrigerator door or adjacent cabinetry. It is advantageous for the user to know whether overloading of the door has occurred by the above described process or by other means. This is accomplished by selecting pins  302  and  312  to have a predetermined threshold of stress, wherein should a pin  302 ,  312  experience a stress above the predetermined threshold, the pin will fail/break. In such a case of failure, a user will be able to visibly see that the pin has broken. In response to seeing a pin is broken, the user will replace the broken pin with an identical pin that has the same predetermined threshold to stress. 
     While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law. For example, the hinge described herein is used for the door of a refrigerator. It is envisioned that the hinge can be used for other types of storage units and for other structures that include a pivoting door.