Patent Publication Number: US-6669315-B2

Title: Lift method for storage bin door

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a divisional of commonly assigned, co-pending, co-invented application Ser. No. 09/723,997, filed Nov. 28, 2000, entitled LIFT MECHANISM FOR STORAGE BIN DOOR now U.S. Pat. No. 6,536,860. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to door mechanisms on storage units, such as for partition-mounted binder bins. However, it should be understood that a scope of the present invention is not limited to only partition-mounted storage units. 
     It is desirable to counterbalance a weight of doors on binder bins so that the doors do not swing closed with a hard action. Further, it is desirable to bias a door into a fully open or fully closed position for aesthetic and ergonomic reasons and also so that the door does not accidentally fall from the open position toward the closed position. However, such biasing devices are generally not available or are undesirably complex. One reason is because an operative weight of the door changes as the door moves between its opened and closed positions, such that it is difficult for a single mechanism to satisfy the force requirements near the open position and at the same time near the closed position. For example, in a door pivoted to a sidewall of a binder bin, the operative weight of the door is at its maximum when the door is near the closed position, because the center of gravity of the door is farthest forward of the pivot point. Contrastingly, when the door is near its opened position, the operative weight is relatively low because the center of gravity of the door is closest to the pivot point. 
     Accordingly, an apparatus is desired having the aforementioned advantages and that solves the aforementioned problems. 
     SUMMARY OF THE PRESENT INVENTION 
     The present invention includes a method of biasing a cover member of a furniture unit between open and closed positions. The method includes steps of attaching a biasing element to the cover member at a first attachment point, and attaching the biasing element to an anchor member at a second attachment point, the anchor member being operably coupled to the furniture unit. The method further includes translatingly moving one of the first and second attachment points from a first position to a second position as the cover member is moved from an open position to a closed position, and still further includes translatingly moving the one attachment point from the second position to the first position as the cover member is moved from the closed position to the open position. The two steps of translatingly moving the one attachment point occur relatively sudden and have the effect of changing an effective length of a torque arm defined by the biasing element. The biasing element biases the cover member with a first biasing force when the one attachment point is in the second position to positively close the cover member, and further the biasing element biases the cover member with a second biasing force when the one attachment point is in the first position to positively open the cover member. 
     In another aspect of the present invention, a method includes steps of providing a biasing element operably attached between a binder bin and a cover member, with the biasing element providing a continuous counter-balancing force to the cover member both when opening and closing the cover member on a front of the binder bin, the biasing element including an anchorage member. The method further includes opening the cover member, with the biasing element providing the counter-balancing force, and suddenly shifting the anchor member as the cover member reaches a near-open position so that the counter-balancing force changes substantially to more positively move the cover member from the near-open position to a full-open position. The method also includes closing the cover member, with the biasing element providing the counter-balancing force, and suddenly shifting the anchor member as the cover member reaches a near-closed position so that the balancing force changes substantially to more positively move the cover member from the near-closed position to a full-closed position. 
     These and other features, objects, and advantages of the present invention will become apparent to a person of ordinary skill upon reading the following description and claims together with reference to the accompanying drawings. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a binder bin embodying the present invention, including a door in a closed position; and 
     FIG. 2 is a perspective view similar to FIG. 1, but with the door in an open position. 
    
    
     DETAILED DESCRIPTION OF THE PRESENT EMBODIMENT 
     A storage bin  10  (FIG. 1) includes a door  11  (sometimes called a “cover member” herein) having a pair of door-supporting arms  12  pivoted to a sidewall  13  of the storage bin for movement between an open position (FIG. 1) and a closed position (FIG. 2) for closing a front opening of the bin  10 . A biasing device  14  is operably connected to at least one of the door-supporting arms  12  for biasing the door  11  as the door  11  nears its open and closed positions. The biasing device  14  includes a spring  15  and a T-shaped shifting anchor  16  connected to the spring  15  that translates and changes a torque arm of a linear spring  15  as the door  11  is moved so that the spring  15 , in combination with a weight of the door  11 , creates a force sufficient to safely close the door  11  during a last portion of door closure movement and so that the spring  15  creates a force sufficient to safely open the door  11  during a last portion of door opening movement. 
     The illustrated door-supporting arm  12  includes a first end  17  pivoted at a main pivot  18  to the sidewall  13 , and includes a second end fixed to a bottom portion of the door  11 . It is contemplated that different door-supporting arrangements can be made and still be used with the present inventive concepts. 
     A dampening device, such as the illustrated silicone pot dampener  20 , is attached to the sidewall  13 . The dampener  20  includes a rack  21  pivoted to the door-supporting arm  12 , and a pot  22  of viscous material. A pinion gear  23  engages the rack  21  and causes a disk to rotate within the pot  22  as the door-supporting arm  12  moves while opening and closing the door  11 . It is contemplated that a variety of different dampening devices can be used and still be within a scope of the present inventive concepts. 
     The spring  15  is extends parallel the door-supporting arm  12 , and includes a first end  25  hooked into a hole  26  to create a pivotable connection. The anchor  16  of the biasing device  14  is T-shaped, and includes a stem  27  that extends parallel the spring  15 , with a second end  28  of the spring being hooked into a hole  29  in an end of the stem  27 . A pair of wheel bearings  30  and  31  engage arms  32  and  32 A of the T-shaped anchor  16 , and support the anchor  16  for linear movement on the bin sidewall  13 . It is noted that a variety of different bearings and engaging members can be used to linearly support a translatable anchor. For example, slots and sliding tabs can be used, linear bearings and telescoping rods can be used, grooves and followers can be used, guide rods and riding pads can be used. The anchor  16  is movable between a first position (FIG. 1) where the stem  27  abuts the bottom wheel bearing  30 , and a second position (FIG. 2) where the stem  27  abuts the top wheel bearing  31 . 
     In the first position (FIG.  1 ), the position of the hole  29  is relatively close to the main pivot  18 . This position is calculated to create a predetermined small torque arm  35  that operates through the anchor  16 , so that the linear force generated by the spring  15  causes a torsional force that, in combination with a weight of the door  11  and door-supporting arm  12 , causes the door  11  to close with a positive but safe action when the door  11  is within the lower half of its path of movement. 
     In the second position (FIG.  2 ), the position of the hole  29  is spaced somewhat from the main pivot  18 . This position is calculated to create a predetermined larger torque arm  36  that operates through the anchor  16 , so that the linear force generated by the spring  15  causes a torsional force that, despite a weight of the door  11  and door-supporting arm  12 , causes the door  11  to open with a positive but safe action when the door  11  is within the upper half of its path of movement. 
     Notably, when the door  11  is in the lowered position shown in FIG. 1, the spring  15  moves the anchor  16  to the lowered second position shown in FIG.  1 . As the door  11  is moved upwardly through the initial half of door movement, the anchor  16  does not shift. As the door  11  is further moved upwardly into the upper portion of its path of movement, the anchor  16  begins to receive an increasing lateral force that tends to bias the anchor  16  toward its “up” position, but it still does not shift. Depending on the frictional and other operating characteristics of the biasing device  14 , the anchor  16  has at least some hysteresis effect where the anchor  16  does not shift until past a mid-point of movement of the door movement. Further, the anchor  16  can have grease or other material that will slow its movement to prevent accelerated harsh movement of the anchor  16  as it moves from one position to another. In the upper portion of the door movement, the anchor  16  shifts (or has shifted) to its “up” position (FIG.  2 ), where the torsional force is calculated to cause the door  11  to move positively but safely to an opened position. 
     When the door  11  is closed, the above effects are reversed. Without repeating all details, the anchor  16  remains in an “up” position (FIG. 2) during a first half of the downward movement of the door  11 . At some time during the middle or intermediate position of the door  11 , the anchor  16  shifts to its lower position. During the lower third of door movement, the anchor  16  along with a weight of the door  11  biases the door  11  to a closed position. The speed and timing of the shifting of the anchor  16  depends on the frictional characteristics of the biasing device  14 , and upon the speed at which the door  11  is opened or closed. 
     The method includes steps of attaching the biasing element  15  to the cover member  11  at a first attachment point, attaching the biasing element  15  to an anchorage member  16  at a second attachment point, with the anchorage member  16  being operably translatably coupled to the furniture unit  10 . The method further includes linearly translatingly moving the anchorage member  16  from a first position to a second position as the cover member  11  is moved from an open position to a closed position and translatingly moving the one attachment point from the second position to the first position as the cover member  11  is moved from the closed position to the open position. The biasing element  15  biases the cover member  11  with a first biasing force when the one attachment point is in the second position to positively but safely close the cover member  11 , and the biasing element  15  biases the cover member  11  with a second biasing force when the one attachment point is in the first position to positively but safely open the cover member  11 . 
     It is noted that the present door arrangement will open or close when released, regardless of the door position. In other words, there is no “dead” zone for the door, when the bearings  30  and  31  are low friction. 
     In the foregoing description, it will be readily appreciated by persons skilled in the art that modifications may be made to the invention without departing from the concepts disclosed herein. For example, it is contemplated that the transition point or “switch-over” point can be changed by design to occur anywhere along the door opening path or door closing path to meet specific user desires or requirements. Such modifications are to be considered as included in the following claims, unless these claims, by their language, expressly state otherwise.