Patent Publication Number: US-8967057-B2

Title: Vertically adjustable platform system

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to U.S. provisional patent application 61/721,876, filed Nov. 2, 2012, the entire content of which is incorporated herein in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to vertically adjustable supports. 
     BACKGROUND OF THE INVENTION 
     There are a wide variety of applications where it is useful to vertically adjust the position of articles resting on a platform. There are devices available that attempt to address this need, including jacks and lifts of various types. However, there remains a need for a vertically adjustable platform system with improved features. 
     SUMMARY OF THE INVENTION 
     The present invention provides embodiments of a vertically adjustable platform system. A first embodiment includes a lifting tower having a pair of opposed faces. The lifting tower has a lifting mechanism disposed therein. A first scissors mechanism is disposed adjacent one of the faces of the tower and has a lower end for engaging a support surface and an upper end. A first platform has an upper surface and is disposed on the upper end of the first scissors mechanism. A second scissors mechanism is disposed adjacent the other of the faces of the tower and has a lower end for engaging a support surface and an upper end. A second platform has an upper surface and is disposed on the upper end of the second scissors mechanism. The lifting mechanism has a first lifting element interconnected with a first scissors mechanism or the first platform for moving the first platform vertically. The lifting mechanism also includes a second lifting element interconnected with the second scissors mechanism or the second platform for moving the second platform vertically. 
     In some versions, the lifting tower includes a first vertical guide bar and a second vertical guide bar. In this version, the first lifting element is a first lifting block that is slidably received on the first vertical guide bar and the second lifting element is a second lifting block that is slidably received on the second vertical guide bar. The lifting mechanism may include a first and second upper sprocket interconnected with an upper end of the lifting tower and a first and second lower sprocket. The lifting mechanism may have a first chain extending around the first upper sprocket and the first lower sprocket, and a second chain extending around the second upper sprocket and the second lower sprocket. The first lifting block may be interconnected with a first chain and directly connected to the first platform for moving the first platform vertically. The second lifting block may be interconnected with the second chain and directly connected with the second platform for moving the second platform vertically. 
     The system may include a first motor driving the first chain and a second motor driving the second chain, wherein the lifting mechanism is operable to vertically move the first and second platforms and to selectively hold the platforms in a vertical position. The motors may be an electric motor with a gear reduction gear box interconnected with one of the lower chain sprockets. The electric motor preferably includes an electric release brake for selectively holding the motor in a position. The motors may be disposed adjacent a bottom end of the tower and generally perpendicular to one of the faces of the tower. The motors may each extend into an area under one of the platforms. 
     The lifting mechanism may be the only mechanism moving the platforms and holding the platforms in a vertical position. The lifting mechanism may be generally disposed between the opposed faces of the tower. 
     In some versions, the platforms each have a first edge and an opposed second edge, with the first edge of the first platform being generally horizontally aligned with the first edge of the second platform and the second edge of the first platform being generally horizontally aligned with the second edge of the second platform. The tower may have a pair of side edges extending between the opposed faces and the side edges may be generally horizontally aligned with the side edges of the platforms. 
     In some versions, a plurality of vertically adjustable platform systems are disposed side-by-side so as to provide a horizontal array of vertically adjustable platforms. 
     The scissors mechanisms may each include at least one set of scissor linkages, with each set of scissor linkages including a first pair of links and a second pair of links. The links each have opposed ends and a midsection with the midsections of each of the links in the first pair being pivotally interconnected to the midsections of one of the links in the second pair. 
     In some versions, the platforms are generally rectangular with inner corners adjacent the lifting tower and outer corners spaced therefrom. The platform system may further include guides for stabilizing articles supported on the platforms. These guides include outer guides that are vertical elements adjacent each of the outer corners. These guides may each have an L-shaped or a T-shaped vertical cross-section with the outer corners being disposed adjacent where the arms of the L-shaped or T-shaped cross-sections come together. The guides may further include inner guides adjacent the inner corners of the platforms and upper horizontal guides extending between the inner guides and outer guides for stabilizing an upper article supported by the platform. 
     A vertically adjustable platform system in accordance with a second embodiment of the present invention includes a lifting tower having a lifting mechanism disposed therein. A scissors mechanism is disposed adjacent the tower and has a lower end for engaging the support surface and an upper end. A platform has an upper surface and is disposed on the upper end of the scissors mechanism. The lifting mechanism has a lifting element interconnected with a platform for moving the platform vertically. 
     In some versions, the lifting tower further includes a vertical guide bar and the lifting element is a lifting bar that is slidably received on the vertical guide bar. The lifting mechanism includes an upper sprocket interconnected with an upper end of the lifting tower and a lower sprocket. The lifting mechanism has a chain extending around the upper sprocket and the lower sprocket. The lifting block is interconnected with the chain and interconnected with the platform. A motor may drive the chain, with the motor being disposed adjacent a bottom end of the tower and generally perpendicular thereto. The motor may extend into an area under the platform. The lifting mechanism may be the only mechanism moving the platform and holding the platform in a vertical position. 
     A vertically adjustable platform system in accordance with a third embodiment of the present invention includes a lifting tower having a pair of opposed faces separate by a tower thickness. The tower includes a lifting mechanism disposed therein with the lifting mechanism being generally disposed between the faces. A first scissors mechanism is disposed adjacent one of the side faces of the tower. The scissors mechanism has a lower end for engaging the support surface and an upper end. A first platform has an upper surface and is disposed on the upper end of the first scissors mechanism. A second scissors mechanism is disposed adjacent the other of the faces of the tower and has a lower end for engaging a support surface and an upper end. A second platform has an upper surface and is disposed on the upper end of the second scissors mechanism. The lifting mechanism has a first and a second upper sprocket and a first and second lower sprocket. The lifting mechanism has a first chain extending around the first upper sprocket and the first lower sprocket and a second chain extending around the second upper sprocket and the second lower sprocket. The lifting tower has a first vertical guide bar and a second vertical guide bar. A first lifting block is slidably received on the first vertical guide bar and a second lifting block is slidably received on the second vertical guide bar. The first lifting block is interconnected with the first chain and connected to the first platform for moving the first platform vertically. The second lifting block is interconnected with the second chain and connected to the second platform for moving the second platform vertically. The lifting mechanism has a first motor driving the first chain and a second motor driving the second chain, such that the lifting mechanism is operable to vertically move the first and second platforms and to selectively hold the platforms in a vertical position. The lifting mechanism is the only mechanism moving the platforms and holding the platforms in a vertical position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of an embodiment of a vertically adjustable platform system in accordance with the present invention; 
         FIG. 2  is another perspective view of the platform system with some components removed; 
         FIG. 3  is a perspective view of the platform system with additional components removed; 
         FIG. 4  is a perspective view of the platform system of  FIG. 1  with optional additional elements; 
         FIG. 5  is a perspective view of a automated produce department that is an application for a platform system in accordance with the present invention; and 
         FIG. 6  is a perspective view of the automated produce department of  FIG. 5  with portions of the outer housing removed. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention provides a system with vertically adjustable platforms for supporting articles and vertically adjusting the position of those articles. Embodiments of the present invention include a platform that is disposed on an upper end of a scissors mechanism and a lifting tower that is adjacent to the mechanism and platform, and includes a lifting mechanism that vertically adjusts the position of the platform. 
     Referring to  FIG. 1 , a first embodiment of a vertically adjustable platform system in accordance with the present invention is shown generally at  10 . The system includes a lifting tower  12 , a first platform  14 , and a second platform  16 . In this embodiment, each platform  14  and  16  has a generally horizontal upper surface and a generally rectangular footprint. The system also includes a first scissors mechanism  18  and a second scissors mechanism  19 , with the first platform  14  being disposed on an upper end of the first scissors mechanism  18  and the second platform  16  being disposed on an upper end of the second scissors mechanism  19 . The lifting tower  12  has a lifting mechanism for vertically adjusting the position of the platforms  14  and  16 . 
     In this embodiment, the scissors mechanisms each include two sets of scissor linkages. Scissors mechanism  18  has a first set of linkages  20  and a second set of linkages  22  with the second set being interconnected with the upper end of the first set. As will be clear to those of skill in the art, more or fewer sets of scissor linkages may be used depending on the application of the mechanism. 
     The linkage  20  includes a first link  24  and a second link  26  that are parallel to one another and spaced apart at opposite sides of the mechanism  18 . A third link  28  and fourth link  30  are also parallel to one another and spaced apart at opposite sides of the mechanism  18 . The first link  24  and the third link  28  are rotatably interconnected with each other at their midportions so as to form an X or a “scissor”. Likewise, the second link  26  and the fourth link  30  are rotatably interconnected with each other at their midportions. In this embodiment, the second link  26  and fourth link  30  are interconnected with one another by a cross brace  32 . This cross brace  32  forces the second link  26  and fourth link  30  to remain parallel and co-planar and maintains a fixed distance between them. By rotating the third link  28  and fourth link  30  relative to the first link  24  and second link  26 , the overall height of the linkage  20  is increased and decreased. 
     The links  24 - 30  may be said to have lower ends and upper ends. The lower ends are adjacent a base member  34  that is interconnected with the lower end of the tower  12  and provides a support surface for the scissors mechanism  18 . Alternatively, the scissors mechanism may be supported on a floor adjacent to the tower  12 . In this embodiment, the lower ends of the links  24  and  26  are pivotally interconnected with the tower  12  and the lower ends of the links  28  and  30  have wheels,  36  and  38  respectively, that roll on the base member  34  as the links rotate with respect to one another. This arrangement maintains the position of the innermost end of the scissors mechanism  18  with respect to the tower  12 . The second set of scissor linkages  22  has the lower ends of its links pivotally interconnected with the upper ends of the links  24 - 30  of the first set of scissor linkages  20 . The platform  14  is disposed on the upper ends of the links in the second set of the scissor linkages  22 . The ends that are closest to the tower  12  are pivotally interconnected with the platform  14  while the ends that are away from the tower have wheels. As such, the edge of the platform  14  closest to the tower remains at a constant distance from the tower. 
     The scissors mechanism  19  is the same as the mechanism  18 , and will not be described in detail. 
     Referring now to  FIG. 1-3 , the lifting tower and lifting mechanism will be described in more detail. As shown, the tower  12  is a generally vertical rectangle. It may be said to have a pair of opposed faces  40  and  42  that are separated by a tower thickness. The first platform  14  and first scissors mechanism  18  are adjacent the first face  40  and the second platform  16  and second scissors mechanism  19  are adjacent the second face  42 . The faces  40  and  42  are open to allow connections between the lifting mechanism and the platforms or scissors mechanisms. The faces  40  and  42  may be said to be interconnected by a pair of vertical side surfaces  44  and  46 . In this embodiment, the side edges of the platforms  14  and  16  are generally aligned with each other and generally aligned with side surfaces  44  and  46  of the tower  12 . 
     The lifting mechanism may take a variety of forms. In the illustrated embodiment, a first upper chain sprocket  48  and a second upper chain sprocket  50  are rotatably interconnected with the upper end of the tower  12 . A first lower chain sprocket  52  and a second lower chain sprocket  54  are located near the bottom of the tower  12  and generally aligned with their respective upper chain sprockets. A first chain  56  extends around the first upper chain sprocket  48  and first lower chain sprocket  52 , and a second chain  58  extends around the second upper sprocket  50  and second lower sprocket  54 . In each case, the chain may be a continuous loop. Alternatively, a belt, such as a toothed belt, may be used in place of a chain. 
     As best shown in  FIG. 3 , the lifting tower further includes a first vertical guide bar  60  and a second vertical guide bar  62 . These each extend generally vertically between the upper and lower ends of the tower  12 . A first lifting block  64  is slidably received on the first vertical guide bar  60  and a second lifting block  66  is slidably received on the second vertical guide bar  62 . The first chain  56  is interconnected with the first lifting block  64  such that movement of the chain causes vertical movement of the lifting block. Likewise, the second chain  58  is interconnected with the second lifting block  66 . The lifting blocks  64  and  66  are, in turn, interconnected with the platforms  14  and  16 . As such, movement of the chains cause vertical movement of the lifting blocks and thereby causes vertical movement of the platforms. In the illustrated embodiment, the lifting blocks are directly connected to an inner edge of the platforms. They could, alternatively, be interconnected with other portions of the platforms or with the scissors mechanism for vertically moving the platforms. In preferred embodiments of the present invention, the lifting mechanism in the tower is the only mechanism that controls the vertical position of the platforms. No additional actuation is provided and the motors hold the platforms in any position, as needed. 
     In the illustrated embodiment, a first motor  68  engages and drives the first lower chain sprocket  52  and a second motor  70  engages and drives the second lower chain sprocket  54 . The motors are rotary motors and include gear reduction gear boxes. The electric motors preferably include an electric release brake for selectively holding the motor in a position. The motors  68  and  70  extend generally perpendicularly from the faces of the tower such that they are disposed in the area under the platforms  14  and  16 . As shown, the crossbars that interconnect the opposing sides of the scissors linkages are shaped so as to clear the motors when the platforms are in their lowest position. 
     Limit switches may be included for determining when the platforms have reached the uppermost or lowermost extent of their travel. One such limit switch is shown at  72  in  FIG. 2 . 
     The design of the lifting tower, lifting mechanism, and scissors mechanisms of the present invention provides several advantages. Typically, scissors mechanisms are moved by drives or actuators that act between links of the scissors mechanism so as to draw them towards one another, thereby lifting an upper end of the scissors mechanism. However, in order to have a power actuated scissors mechanism with an actuator acting between linkages, the actuator must necessarily be disposed in an area that would be below the platform of the present invention. This interferes with moving the platform to its lowermost position. The mechanical advantage of the actuator also changes as the relative position of the links changes. The present mechanism allows a much more compact position for the scissors mechanism in its lowest position. Unlike other scissors mechanisms, the lifting mechanism of the present invention lifts the platform itself, with the scissors mechanism following along and acting to keep the platform level and stable, rather than using the scissors mechanism to lift the platform. The present mechanism also allows very smooth movement of the platform throughout its range of motion, since the mechanical advantage is constant. The arrangement of the motors, chains, and lifting blocks is also very compact, allowing the thickness of the tower between the faces  40  and  42  to be very small. In one example, the tower has an overall height of approximately 42 inches, a thickness between the faces  40  and  42  of approximately 3½ inches, and a side-to-side width between the sides  44  and  46  of approximately 16½ inches. In this example, the platforms have a side-to-side width of approximately 16 inches and an end-to-end length of approximately 25 inches. The platforms, in their lowermost position, are approximately 34 inches below the top of the tower and about 7½ inches above the support surface. In their uppermost position, the platforms may be at or near the top of the tower, giving a range of motion of approximately 34 inches. Other dimensions and configurations may also be used. 
     The design of the lifting mechanism allows the platforms  14  and  16  to be generally aligned with each other rather than being staggered. Alternatively, the platforms may be staggered, if desired. 
     Referring now to  FIG. 4 , the platform system is shown with optional guides and covers. The platform system may be used to support a vertical stack of articles on the upper surface of each platform. In order to stabilize the stack of articles, guides may be provided. In the embodiment illustrated in  FIG. 4 , the platform  14  may be said to have an inner end  80  and an outer end  82 , as well as opposed side edges  84  and  86 . Inner side guides  88  and  90  may be provided adjacent the side edges  84  and  86  at the inner end  80 . In the illustrated embodiment, these guides  88  and  90  are flat elements that extend vertically along the sides of the platform and extend for its entire range of motion. Additional outer guides  92  and  94  are vertical members with an L-shaped or T-shaped cross-section and are positioned at the corners where the outer end  82  meets the side edges  84  and  86 . The corners of the platform  14  are adjacent the area where the legs of the L-shaped or T-shaped guides  94  come together. Top guides  96  and  98  may also be provided. In this embodiment, the guides  96  and  98  extend between the upper ends of the guides  88  and  92 , and  90  and  94 , respectively. These guides may have inner surfaces that are slightly closer together than the inner surfaces of the guides  88  through  94  so as to snugly hold an article at the uppermost end of a stack on the platform  14 . The illustrated embodiment also includes a cover  100  that extends down from the outer edge  82  of the platform so as to cover the area below the platform where the scissors mechanism is provided. This cover  100  may be cosmetic or may serve the function of limiting airflow between areas on the two sides of the cover. In some versions, the cover  100  is stowed on a roll attached to the outer edge  82  of the platform  14  and unrolls as the platform moves upwardly. 
     Thus far, the vertically adjustable platform system of the present invention has been described as having a lifting tower and two platforms adjacent thereto. According to an alternative embodiment, a single platform is provided for use with a tower. This embodiment is used for applications requiring only a single platform or where multiple platforms need to be arranged in an arrangement not on two sides of the tower. 
     As will be clear to those of skill in the art, a vertically adjustable platform system in accordance with the present invention has a wide variety of uses.  FIG. 5  illustrates an automated produce department  102 , which represents one application for the vertically adjustable platform system. The automated produce department includes a housing  104  that encloses a display area.  FIG. 6  illustrates the automated produce department  102  with portions of the housing removed. As shown, the automated produce department utilizes a plurality of vertically adjustable platform systems in accordance with the present invention, arranged side-by-side. Produce is provided in packages  106 , with multiple packages provided in a produce tray  108 . A plurality of trays are stacked in a vertical stack on a platform of the vertically adjustable platform system  110 . As trays of produce are depleted, the tray is removed by the automated produce department and the platform system adjusts the vertical position of the platform so as to maintain a generally horizontal display of produce. It is desirable that a platform system for such an application provide a large range of motion, a very compact lowermost position, and a smooth movement of the platform to a variety of positions. In some embodiments, the platform system includes electronic sensors for sensing the position of items stacked on the platforms. Referring to  FIGS. 2 and 4 , an electronic sensor is shown at  73 . This sensor may be a photoelectric sensor that senses when the upper edge of a produce tray reaches the level of the sensor. This may form part of a control system wherein when a tray is removed, the platform system moves the platform upwardly until the electronic sensor  73  determines that the next tray has reached the desired level. When the last tray is removed, the platform may move upwardly until the limit switch  72  determines that it has reached the top of its travel. Sensors may be provided on each side of the tower for use with both platforms. Other types of sensors may also be used. 
     As will be clear to those of skill in the art, the herein discussed embodiments of the present invention may be altered in various ways without departing from the scope or teaching of the present invention. It is the following claims, including all equivalents, which define the scope of the invention.