Abstract:
The present invention is generally directed to an elevator for multi-level rack storage systems that can automatically and continuously transfer loads from an upper level to a lower level without the use of an external power source.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to multi-level storage systems and, more particularly, to multi-level storage systems having an automatic elevator for the efficient storage and delivery of goods. The present invention is particularly advantageous when used in warehouse applications where a single storage bay is used for a single product, such as in the grocery sector where first-in-first-out storage is desirable. 
     An important consideration in the storage or warehouse industry, including the grocery sector, is the ability to safely and efficiently load and unload stored products while maintaining a high storage density for a given storage area. Another important consideration in the grocery sector, among others, is the ability to efficiently store and retrieve loads on a first-in-first-out basis. Various systems capable of accommodating these considerations are shown and described in U.S. Pat. Nos. 5,476,180, 5,617,961, 5,642,976 and 6,186,725. 
     SUMMARY OF THE INVENTION 
     The present invention preserves the advantages of the various known first-in-first-out storage systems and also provides new features and advantages. For example, the present invention provides a load storage and unloading system that can automatically deliver loads from an upper storage level to a lower level for unloading. The system of the present invention is capable of the continuous and automatic transfer of loads from the upper level to the lower level, without the use of an external power source or other complicated arrangements. 
     In a preferred embodiment of the present invention, a load storage system is provided having a two-tiered flow rail conveyor system. The system includes an upper set of input flow rails which are inclined toward the rear of the system and which form an input conveyor, and a lower set of output flow rails which are inclined toward the front of the system and which form an output conveyor. The input and output flow rails provide the surfaces upon which loads may roll. At the rear end of the system is an elevator assembly, the deck of which also provides a surface upon which loads may roll. Upon receipt of a load from the input conveyor, the elevator automatically and smoothly lowers the load to the output conveyor for unloading. An elevator lock and release mechanism retains the elevator in its lowered position until the load to be transferred clears the elevator assembly as it rolls along the output conveyor. Once the transferred load clears the elevator assembly as it rolls along the output conveyor, the elevator automatically returns to the input conveyor for receipt of another load. Since the system typically contemplates the storage of multiple deep loads, e.g., two or more on the input and/or output conveyors, an automatic load stop is provided on the input conveyor to prevent a load from rolling onto the elevator assembly when it is not in a fully raised position and ready to receive a load. In addition, a reverse flow mechanism is provided so that the elevator deck assembly is at the proper angle to receive a load as well as being at the proper reverse angle to transfer a load. Rolling brakes or other means may also be provided along the input conveyor to maintain the proper spacing along the input flow rails between a load entering the elevator and a subsequent load. 
     Accordingly, an object of the present invention is to provide a multi-level storage system having an elevator that efficiently stores and delivers loads on a first-in-first-out basis. 
     Another object of the present invention is to provide a multi-level storage system that includes an elevator to automatically deliver a load from the upper level of the system to the lower level of the system. 
     Yet another object of the present invention is to provide a multi-level storage system with an elevator that provides high storage density for a given storage area. 
     A further object of the present invention is to provide a storage system that automatically delivers a load to the lower level of the system using an elevator which is self-contained and does not rely upon external power sources. 
     Still another object of the present invention is to provide an elevator for use in transferring loads in a variety of multi-level storage applications. 
     An additional object of the present invention is to provide a multi-level storage system that operates on a first-in-first-out basis. 
     Still a further object of the present invention is to provide an elevator with a reverse flow mechanism so that the elevator deck assembly is at the proper angle to receive and then transfer a load. 
     INVENTOR&#39;S DEFINITION OF THE TERMS 
     The terms used in the claims of this patent are intended to have their broadest meaning consistent with the requirements of law. Where alternative meanings are possible, the broadest meaning is intended. All words used in the claims are intended to be used in the normal, customary usage of grammar and the English language. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The stated and unstated features and advantages of the present invention will become apparent from the following descriptions and drawings wherein like reference numerals represent like elements in the various views, and in which: 
     FIG. 1 is a side perspective view of an embodiment of the present invention shown with the elevator in the up position and with portions removed for clarity; 
     FIG. 1A is a side perspective view of an embodiment of the present invention with the elevator in the up position and with portions removed for clarity; 
     FIG. 2 is a side perspective view of an embodiment of the present invention shown with the elevator in a lowered position and with portions removed for clarity; 
     FIG. 3 is a side elevational view of an embodiment of the present invention with the elevator in a raised position and with portions removed to show the components and operation of the elevator assembly, load stop assembly, elevator lock and release assembly and reverse flow mechanism; 
     FIG. 4 is a side elevational view of components of an embodiment of the elevator guide arms of the present invention; 
     FIG. 5 is a side elevational view of an embodiment of the present invention of FIG. 3 shown with the elevator in a lowered position; 
     FIG. 6 is a side elevational view of an embodiment of the present invention of FIG. 3 shown with the elevator in an intermediate position and returning to the raised position; 
     FIG. 7 is a side elevational view of components of an embodiment of the load stop mechanism and portions of the elevator deck assembly of the present invention; 
     FIG. 8 is a side elevational view of the elevator lock and release assembly and portions of the elevator deck assembly of the present invention; 
     FIG. 8A is a side elevational view of an alternative embodiment of an elevator lock and release mechanism of the present invention. 
     FIG. 9 is a cross-sectional view through an embodiment of the elevator deck assembly of the present invention. 
     FIG. 10 is a schematic view of three systems of the present invention stacked on top of one another. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Set forth below is a description of what is currently believed to be the preferred embodiment or best representative example of the inventions claimed. Future and present alternatives and modifications to the preferred embodiment are contemplated. Any alternatives or modifications which make insubstantial changes in function, purpose, structure or result are intended to be covered by the claims of this patent. 
     A multi-level storage system having an automatic elevator in accordance with the present invention is shown generally as  10  in the Figures. By reference to FIGS. 1,  1 A and  2 , a multi-level storage system  10  includes a two-level flow rail conveyor system  20 , a support structure  30 , and an elevator assembly  40 . As used herein, the term “load” is used in its broadest possible sense to include pallets, containers or parts bins, slip sheets, carts, unit loads and the like. 
     The support structure  30  is designed to support the flow rail conveyor system  20 , as well as the loads to be stored. The configuration of a preferred support structure  30  includes a number of parallel columns  32 , beams  34  interconnecting the columns  32  and support braces  36 . It will be understood by those of ordinary skill in the art that any number of support structures  30  may be placed in side-by-side relationship or stacked on top of one another as the particular application and available space dictate. For example, if an even number of levels is used, loading and unloading take place from the same aisle. If an odd number of levels is used, loading and unloading take place in separate aisles, as shown in FIG.  10 . 
     Moreover, depending upon the design load, any necessary support may be provided by additional or larger columns  32 , beams  34 , braces  36  and the like, which may be connected in a variety of ways, such as bolts, welding and the like. In addition, channel structural members are shown and used for many of the components in the preferred embodiment of the support structure  30  and other assemblies. It will be understood, however, that a wide variety of cross-sectional shapes, including rectangular, square, round tube and hot-rolled I and S beam cross-sections, may also be used for the support structure and other components and assemblies of the present invention. 
     In a preferred embodiment of the present invention, flow rail conveyor system  20  includes a plurality of input flow rails  22  which are inclined downward toward the rear of the system  10  to permit the load to be loaded on the system and roll smoothly toward the rear of the system. A plurality of output flow rails  24  are also provided. Output flow rails  24  are inclined downward to the front of the system so that loads, after transfer from the elevator assembly  40 , roll smoothly down output flow rails  24  and can be unloaded from the system  10 . 
     Flow rail conveyor system  20  consists of three spaced parallel input flow rails  22  and three spaced parallel output flow rails  24 . As will be understood by those of ordinary skill in the art, the input flow rails  22  and output flow rails  24  may be formed from a series of in-line rollers that define rolling surfaces which permit a load to roll along their length. However, depending upon the type of loads to be stored and the design loads of the system, a single flow conveyor assembly, two parallel rows of flow rail conveyor assemblies or other types of flow assemblies may be used. 
     The structure and operation of the elevator assembly  40  (and the other assemblies that cooperate with it) is shown by reference to FIGS. 3 through 9. In a preferred embodiment of the present invention, the elevator assembly  40  includes a pair of parallel spaced rear elevator columns  42  and a pair of spaced parallel front elevator columns  44 . The elevator columns  42  and  44  are designed to fit within support structure  30 , (see FIG. 1) leaving sufficient space for the operation of the elevator as hereinafter described. An elevator deck assembly  45  is provided which includes a pair of elevator flow rails  46  which are supported by and pinned at one end to elevator deck frame members  47 . Elevator flow rails  46  provide the rolling surface for the loads entering and exiting the elevator deck assembly  45 . As best shown in FIGS. 7 and 8, elevator flow rails  46  are pinned  41  at their forward end to deck frame members  47  by well known means. The height of pin  41  is designed so that the slope of the elevator flow rails  46  is consistent with the slope of the input flow rails  22 . In this manner, a load may flow smoothly down input flow rails  22  and onto the elevator flow rails  46 . 
     In a preferred embodiment of the present invention, elevator deck assembly  45  is generally rectangular and includes four tubular sleeve members  48  in each corner of the deck assembly  45 . As shown, the tubular sleeve members  48  are interconnected by elevator deck frame members  47 . Sleeve members  48  are designed to slide up and down along elevator columns  42  and  44  and guide elevator deck assembly  45  as it ascends and descends to transfer loads as hereinafter described. A hook  49  is pivotably attached to one of the deck frame members  47  and hangs vertically below elevator deck assembly  45  (see FIG.  8 ). A torsion spring (not shown) keeps the hook in the vertical position and enables the hook to deflect slightly when deck assembly  45  is locked in its lowered position as hereinafter described. 
     It will be understood by those of ordinary skill in the art that the generally rectangular elevator deck assembly  45  may take a variety of configurations and be made from a variety of structural members, depending upon the particular application and design loads. Similarly, although the preferred embodiment utilizes separate elevator support columns  42  and  44  and tubular sleeves  48  that slidably engage the elevator support columns  42  and  44 , various other embodiments may be readily utilized. For example, components of the support structure system  30  may be used to guide and/or support elevator deck assembly  45  as required. In addition, instead of the guide sleeve members  48 , other types of brackets, bearings or other means may be used to restrict the lateral movement of the elevator deck assembly  45  while permitting it to smoothly ascend and descend as contemplated by the present invention. 
     In a preferred embodiment of the present invention, the elevator deck assembly  45  is supported by and rendered operable though a series of components, which include a pair of elevator guide arms  51 , a pair of dampers  53  and a pair of gas springs  55  (all shown schematically in FIGS. 3,  5  and  6 ). An opposing pair of damper brackets  57  are also provided that are used to support and/or pivotably mount various components of the elevator assembly  40  as hereinafter described. Alternatively, portions of the support structure  30  may be used to support and mount some or all of the components of elevator assembly  40 . 
     In a preferred embodiment, roller bearings  60  are attached to both sides of elevator deck assembly  45  to side deck frame members  47  through bolts  61  or other well known means (see FIG.  9 ). Roller bearings  60  enable elevator deck assembly  45  to ride along the top surface of elevator guide arms  51  as elevator deck assembly  45  operates through its range of motion. Support angles  63  may also be provided to help protect roller bearings  60 . The front end  62  of elevator guide arms  51  is pivotably mounted by well known means to a brace  36  or other suitable components of support structure  30  member. One end of damper  53  is pivotably mounted to elevator guide arm  51  and the other end pivotably mounted to damper brackets  57 . Similarly, gas spring  55  is pivotably mounted at one end to elevator guide arm  51  and at the other end to damper bracket  57 . The gas spring  55 , damper  53  and guide arm  51  enable the elevator deck assembly  45  to smoothly lower and transfer and load, and smoothly and automatically return the elevator deck assembly  45  to its upper position to secure the next load. 
     For example, when a load rolls on to the elevator deck assembly  45 , the weight of the load overcomes the force from the gas springs  55  and the load and elevator deck assembly  45  begin to descend. As elevator deck assembly  45  descends along elevator columns  42  and  44 , the bearings  60  ride along the top of elevator guide arms  51  (compare FIGS. 3,  5  and  6 ) as elevator guide arms  51  rotate downward about their pivot points. The rate of descent of elevator deck assembly  45  and the load is smoothed and regulated by dampers  53 , which also carry some of the excess loads on gas springs  55 . When the elevator deck assembly  45  reaches its lowered position and elevator deck rollers  46  are adjacent to the output flow rails  24 , the elevator deck assembly  45  is locked in the lowered position by an elevator lock and release assembly  80  (and the hook  49 ) and the load then rolls off of the elevator deck assembly  45 . Once the load sufficiently clears the elevator deck assembly  45 , the elevator lock and release assembly  80  unlocks the elevator deck assembly as hereinafter described. The force of the gas springs  55  are then greater than the weight of the unloaded elevator deck assembly  45 , and the elevator deck assembly  45  is raised to its upper position to receive another load by the gas springs  55 . 
     It will be understood by those of ordinary skill in the art that in designing the system, it is important to select and adjust the gas springs  55  by consideration of the weight of the deck assembly  45  and the weight of the loads contemplated. For example, the vertical weight of deck assembly  45  and a pallet and load should be slightly greater than the vertical force exerted by gas springs  55  on deck assembly  45  through guide arms  51  so that the load and elevator deck assembly  45  may descend. In the preferred embodiment of the present invention, the preferred adjustable gas springs  55  are presently available from Hahn Gas Springs of Aichschieb, Germany (i.e., its gas spring model no. G 2040 1000 2200 WG45 WG45). Although other types and makes of gas springs may be used in the present invention, these gas springs are believed to provide the best operation and adjustability. Other acceptable gas springs are available from Suspa, Inc. of Grand Rapids, Mich. and Stabilis of Colmar, Pa. Similarly, oil dampers  53  are also presently available from Hahn Gas Springs (model no. D 1440 7502 1630 WG35 WG35). Other suitable dampers that can provide controlled action as contemplated herein which can handle the design load and control the descent of the load may also be used. 
     The range of motion of the elevator deck assembly is controlled by the strategic placement of upper elevator stops  50  and lower elevator stops  52 . When the elevator deck assembly  45  is in the upper position, it is forced against upper elevator stop  50  by the gas springs  55 . When the elevator deck assembly  45  is in the lowered position with a load, the elevator deck assembly  45  is forced against lower stops  52  by the weight of the load. The elevator stops  50  and  52  may take a form similar to tubular sleeve members  48 , although other means may be readily employed. Elevator stops  50  and  52  may be bolted, welded or the like onto the desired position on front elevator columns  44  and rear elevator columns  42 . 
     The flow of loads along input flow rails  22  to elevator deck assembly  45  is controlled by a load stop assembly  70  (see FIG.  7 ). The structure and operation of preferred load stop assembly  70  is shown and described in U.S. Pat. No. 5,873,473, which is incorporated herein by reference. The load stop assembly  70  is mounted to the input flow rails  22  at a desired position along their length. A stop plate  73  is provided which is designed to engage and stop the load (see e.g., FIG. 6) when in the stop position. 
     In a preferred embodiment of the present invention, load stop  70  is automatically operated in conjunction with the elevator deck assembly  45 . Specifically, a lever  76  is provided which is pivotably mounted  77  to a beam  34  or other member of support system  20 . Lever  76  is designed to be engaged by elevator deck assembly  45  when the assembly is in its upper position. When lever  76  is so engaged, it pulls a cable  74  (a rod, bar or other linkage may also be used) which forces load stop  70  to assume a release position and permit a load to roll onto elevator deck assembly  45 . When that occurs, elevator deck assembly  45  begins the descend and disengages lever  76 , which in turn, through cable  74 , activates load stop  70  into a stop position, prohibiting another load from passing, except when the elevator deck assembly  45  is in its top position to properly receive a load. 
     In addition, retarders or brakes  11  (see FIGS. 1A and 2) may be incorporated along the input flow rails  22  in order to slow the flow of and separate any loads in the system, especially when multiple depth systems are used. Their type and incorporation will be understood by those of ordinary skill in the art. In general, however, such retarders may take the form of a large rubber roller having a centrifugal brake assembly, the surface of which contacts the bottom of a roller which is in contact with the lower surface of the load. In this manner, among others, the flow of containers may be slowed and desired spacing maintained between loads, particularly as one load is entering elevator assembly  40 . 
     An elevator lock and release assembly  80  is also provided (see FIG. 8) which is designed to hold the elevator deck assembly  45  in its lowered position so that a load may smoothly transfer from elevator deck assembly  45  onto the output flow rails  24 . The principal components of lock and release mechanism  80  are also shown and described in the Pater &#39;473 patent and are simply oriented in a vertical manner to engage hook  49 , which extends from frame member  47  of deck assembly  45 . When elevator deck assembly  45  reaches its lowered position, a latch  75  engages hook  49  and keeps the elevator deck assembly  45  in the lowered position while a load is being transferred to the output flow rails  24 . Once the load is transferred to and rolls along the output flow rails  24 , the load depresses lever  83 , which is placed a sufficient distance along output flow rails  24 . Lever  83  pushes a common link  84  through rod  82 . The common link  84  rotates about its center. A spring loaded pin  87  in the top of the common link  84  pulls a horizontally fixed link  85  which is attached to a cable  81 . Cable  81  pulls the vertically oriented elevator lock and release assembly  80  which temporarily collapses and releases hook  49 , and the elevator deck assembly  45  then raises to assume a position to receive another load. Pin  87  eventually rotates away and separates from catch  88  of link  85 . As soon as pin  87  and catch  88  separate, the torsion spring from the elevator lock and release assembly  80  retracts horizontal link  85  to its initial position. Once the load that has just activated the elevator lock and release assembly  80  moves past and clears lever  83 , a torsion spring (not shown) sets lever  83  back to its initial vertical position. As the torsion spring resets lever  83 , it pulls rod  82 , which rotates common link  84 . The spring loaded pin  87  in the common link  84  compresses under the catch  88  of the horizontal link  86  until it clears and then resets to engage the inside of the catch  88  of the horizontal link  85  is then ready to be reactivated with the next load. 
     An alternative embodiment of elevator lock and release mechanism  80  is shown in FIG.  8 A. As shown therein, cable  81  may be a wire rope, rod, bar and the like which is operably connected to horizontal link  85 . Alternate pin arrangement  87  shown in FIG. 8A may then work by gravity or with spring (not shown) assist. 
     A reverse flow mechanism  56  is also provided. Specifically, a reverse slope beam  58  is provided which may be attached to lower stop  52  through a beam  54  or other suitable cross member, or even the ground. The reverse flow mechanism  56  is needed because when the elevator deck assembly  45  is in the upper position, it must be sloped to properly receive the load from the input conveyor  22 . However, the elevator flow rails  46  must reverse slope to transfer the load to the output conveyor  24 . As previously indicated, this is achieved by pinning  41  elevator flow rails  46  at one end (here, the forward end) and allowing them to rest on frame members  47  at their free end. When the elevator assembly  45  descends to the lower level, the rear, free end of the elevator flow rails  46  contact the reverse slope beam  58  while the rest of the elevator deck assembly keeps lowering until in contact with lower stops  52 . When in this position, elevator flow rails  46  reverse slope to coincide with the output conveyor  24 . 
     In the operation of the present invention, a load is placed on the front of the system onto input flow rails  22 . The load rolls downward toward the rear of the system. If elevator deck assembly  45  is in the raised position, the load rolls onto elevator flow rails  46  and the elevator deck assembly  45  and the load begin their descent. At this point, since elevator deck assembly  45  has disengaged lever  76 , the load stop assembly  70  assumes a stop position with stop plate  73  ready to engage and stop a subsequent load while the elevator deck assembly  45  transfers a load. As previously described, the spacing of a subsequent load may be accomplished with a brake or retarder mechanism. 
     When elevator deck assembly  45  and the load reach the lowered position reverse slope beam  58  of reverse flow mechanism  56  engages the free end of the elevator flow rails  46 , causing the slope of the elevator flow rails  46  to reverse and generally align with output flow rails  24 . When elevator deck  45  reaches lower stops  52 , elevator lock and release assembly  80  engages hook  49  and lock elevator deck assembly  45  in the lowered position. The load then rolls onto output flow rails  24 . As it rolls along output flow rails  24 , the load contacts lever  83  and, as described above, releases elevator deck assembly  45  which then ascends. At its uppermost position, elevator deck assembly  45  engages lever  76  which, as described above, ,lowers load stop assembly  70 , thereby permitting the subsequent load to roll onto elevator deck assembly  45  for transfer. In this manner, the smooth and efficient transfer of loads using an automatic elevator is accomplished. 
     The above description is not intended to limit the meaning of the words used in the following claims that define the invention. Rather, it is contemplated that future modifications in structure, function or result will exist that are not substantial changes and that all such insubstantial changes in what is claimed are intended to be covered by the claims. Thus, while preferred embodiments of the present inventions have been illustrated and described, it will be understood that changes and modifications can be made without departing from the claimed invention. 
     Various features of the present inventions are set forth in the following claims.