Abstract:
A pallet dispenser can receive a vertical stack of skewed or misaligned pallets in an interior of a frame of the pallet dispenser and align the pallets as they are sequentially dispensed from the pallet dispenser onto a conveyor below the pallet dispenser. The pallet dispenser that can be quickly manually changed over to accommodate pallets of different sizes and vertically dispense the pallets one by one onto a conveyor below the pallet dispenser. The pallet dispenser is provided-with a quick, manual change over that enables the pallet dispenser to be quickly adjusted to accommodate a vertical stack of large or small pallets to be reoriented and dispensed by the pallet dispenser onto a separate conveyor without appreciable downtime of the pallet dispenser or the conveyor with which it is used.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention pertains to a pallet dispenser that can receive a vertical stack of skewed or misaligned pallets in an interior of the pallet dispenser and align the pallets as they are sequentially dispensed from the pallet dispenser onto a conveyor below the pallet dispenser. More specifically, the present invention pertains to a pallet dispenser that can be quickly manually changed over to accommodate pallets of different sizes and vertically dispense the pallets one by one onto a conveyor below the pallet dispenser. 
     2. Description of the Related Art 
     There are many different known types and sizes of pallet constructions that are employed in supporting goods when being shipped. The pallets are designed to be lifted by conventional forklift trucks and provide a base for large goods or for large numbers of goods that would be difficult to be manually lifted and transported. By supporting large, heavy goods or large numbers of goods on a pallet, the goods can be easily transported, for example from a loading dock to a truck bed or vice versa, by a conventional forklift truck. 
     Most conventional pallets are constructed of wood and/or plastic and are intended to be reused several times. Emptied pallets that are to be reused are usually stacked upon each other in a storage area until they are needed. Often the stacking of the used pallets is done manually as the pallets are emptied, resulting in skewing or misalignment of the vertically stacked pallets in many instances. What is meant by skewing or misalignment is that the sides of the pallets in the vertical stack are not aligned and adjacent pallets are staggered or slightly turned relative to each other. 
     In pallet dispensers that are employed in combination with conveyor systems, the skewing or misalignment of pallets loaded into the pallet dispenser must be corrected before the dispenser dispenses a pallet onto the conveyor system. This is necessary so that the pallets dispensed onto the conveyor system are properly oriented relative to the conveyors so that goods to be loaded onto the pallets conveyed by the conveyor system are properly positioned on the pallets. For example, in an automated conveyor system that stacks layers of rows of goods on a pallet conveyed through the system, the pallet must first be correctly oriented relative to the conveyor in order to ensure that the layers of rows of goods are properly positioned on the pallet. 
     To achieve the proper orienting of the pallets dispensed from a pallet dispenser onto a conveyor system, prior art pallet dispensers typically had guide rails at their opposite sides and their fronts and backs that would engage the four sides of a pallet as it is dispensed from a vertical stack of pallets positioned in the interior of the pallet dispenser. The guide rails would engage with the four sides of the pallets as they are dispensed vertically downward through the pallet dispenser and orient the bottom most pallet of the stack just prior to its being dispensed onto the conveyor system below the dispenser. 
     However, pallets are manufactured in a variety of sizes and primarily in a large size that measures 56″ by 44″ and a small size that measures 48″ by 40″. If a stack of small pallets is loaded into a pallet dispenser whose guide rails have been previously adjusted and set to reorient a stack of large pallets, the guide rails of the pallet dispenser would have to be manually adjusted to reorient the small pallets of the stack of pallets loaded into the pallet dispenser. Additionally, if a stack of large pallets is to be loaded into a pallet dispenser that had been previously adjusted to dispense a stack of small pallets, the guide rails of the pallet dispenser would have to be manually adjusted and reset in order to first receive the stack of large pallets in the interior of the pallet dispenser and then to properly orient the large pallets as they are dispensed from the pallet dispenser. Because prior art pallet dispensers typically would have guide rails on all four sides of the dispenser to engage all four sides of the pallets dispensed vertically downward through the dispenser, adjusting the positions of guide rails to accommodate stacks of different size pallets would require a considerable amount of labor time. This labor time was not only down time for the pallet dispenser as its guide rails are adjusted, but also down time for the entire conveyor system as the system waits for additional pallets to be dispensed by the pallet dispenser. This down time significantly decreases the cost efficiency of running a conveyor system. 
     Furthermore, large pallets and small pallets differ in their construction in that the cross beams of the pallets that are spatially arranged between the top and bottom panels of the pallets or the top and bottom sheets or boards of the pallets usually have a different spacing between the beams. The prior art pallet dispensers would have actuator arms that would project horizontally into the interior volume of the pallet extending between the cross beams of the bottom most pallet of the stack and thereby support the vertical stack of pallets in the pallet dispenser interior. Retracting the actuator arms would cause the bottom most pallet to be dispensed downwardly onto the conveyor, a portion of which would typically be raised to receive the bottom most pallet. As the portion of the conveyor is lowered after receiving the bottom most pallet, the actuator arms would again be extended into the pallet dispenser interior to engage between the crossbeams of the next pallet of the stack and support the stack of pallets in the pallet dispenser interior as the previously dispensed pallet is lowered and conveyed out of the dispenser. Because large and small pallets have different numbers of cross beams that have different positions in the pallets, it would also be necessary to adjust the length of the actuator arms when the pallet dispenser is to be changed over from dispensing large pallets to dispensing small pallets, or vice versa. 
     What is needed to overcome the disadvantages associated with prior art pallet dispensers is a way of quickly changing over the pallet dispenser to accommodate vertical stacks of pallets of different sizes. 
     SUMMARY OF THE INVENTION 
     Much of the construction of the pallet dispenser of the invention is similar to that of prior art pallet dispensers and therefor is not described in detail. The pallet dispenser is basically comprised of a rectangular base that is dimensioned to support both large and small pallets in an interior area of the base above a conveyor apparatus with which the dispenser is used. The conveyer is not part of the invention but a typical conveyor employed with pallet dispensers has a portion positioned beneath the pallet dispenser that raises to accept a pallet at a bottom of a vertical stack of pallets supported by the dispenser and then lowers incrementally to enable the pallet dispenser to engage with the next pallet above the pallet on the conveyor so that the pallet on the conveyor can be separated from the remainder of the pallets in the vertical stack supported in the interior of the pallet dispenser. 
     The bottom most pallet is separated from the remainder of the pallets in the vertical stack by actuator arms of the dispenser supported on the base. The actuators of the actuator arms cause the arms to swing out from the base through an arc to positions where they project inwardly from opposite sides of the base toward the base interior. As the arms are actuated and swing out through the arc of movement, they pass between the top and bottom panels of the pallet to be engaged by the arms and in between cross beams of the pallet. However, because the pallet dispenser of the invention is designed to dispense both large and small pallets, the actuator arms of the dispenser are modified. The modification is necessary because longer actuator arms needed to reach into the pallet dispenser interior a sufficient distance to engage with smaller pallets would likely engage with cross beams of larger pallets loaded into the pallet dispenser interior before they complete their arc of movement. To avoid this problem, the actuator arms of the invention are constructed in two parts that are connected to each other for linear sliding movement between at least two adjusted lengths of the actuator arms. A manually operated pin holds the actuator arms in their two adjusted length positions. In this manner, the lengths of the actuator arms can be increased to engage small pallets stacked in the pallet dispenser and the lengths of the actuator arms can be decreased to engage large pallets stacked in the pallet dispenser. 
     A frame of the pallet dispenser extends upwardly from a top of the base. The frame has an interior positioned above the base interior and is dimensioned sufficiently large to receive a vertical stack of large pallets in the frame interior. The frame supports vertical upright assemblies at the opposite left and right sides of the pallet dispenser and supports a rear vertical upright assembly at the rear of the pallet dispenser. The front of the frame is basically left open to provide sufficient access for a forklift truck to deposit a stack of pallets into the frame interior through the front of the frame. 
     Each of the left and right vertical upright assemblies and the rear upright assembly is comprised of a pair of rails that are suspended from pivot connections of the rails at the top of the frame. Each pair of rails hangs downwardly through the frame interior to bottom portions of the rails that are angled inwardly toward the frame interior. The pairs of rails are designed to guide pallets in a vertical stack toward the center of the pallet dispenser base as pallets are-sequentially dispensed vertically downward through the frame interior. The inwardly angled portions of the rails at their bottom ends orient the lower pallets of the stack in their desired position relative to the conveyor with which the dispenser is used just prior to the pallets being dispensed onto the conveyor. 
     Each of the vertical upright assemblies is provided with a manual handle that is used to move the vertical upright assemblies between first and second adjusted positions of the assemblies relative to the frame. In the first positions of the vertical upright assemblies, their rails are moved inwardly toward the frame interior. In their first positions, the left and right side vertical uprights and the rear vertical uprights guide a stack of small pallets vertically downward through the frame interior. The inwardly angled lower portions of the rails of the upright assemblies orient the bottom most pallet of the stack of small pallets in its desired orientation prior to being deposited onto the conveyor beneath the dispenser. When the manual handles of the vertical upright assemblies are moved toward their second positions, the rails of the vertical upright assemblies are moved outwardly away from the frame interior to their second positions. In the second positions of the rails, the lower portions of the rails orient the bottom most pallet in a stack of large pallets in its desired position prior to being dispensed onto the conveyor below the dispenser. 
     The manual handles of each of the vertical upright assemblies are basically comprised of pivot shafts at opposite sides of the assemblies that are mounted in bushings on the dispenser base and horizontal rods that are mounted to the shafts at opposite ends of the rods. A manual hand hold is mounted to each rod intermediate its opposite ends. The shafts provide a pivoting connection of the rods and the hand holds to the base that pivots about a horizontal axis of the shafts. By gripping the hand holds, the rods can be pivoted about the shafts and moved through an arc toward the frame interior to first positions of the manual handles and away from the frame interior to second positions of the handles. The opposite ends of the rods engage in vertical slots of the pair of rails of the vertical upright assemblies for sliding movement of the rod ends through the slots as the rods are moved through an arc between their first and second positions. Moving the rods to their first positions causes the vertical upright assemblies to move to their first positions relative to the frame, and moving the rods to their second positions causes the vertical upright assemblies to move to their second positions relative to the frame. In this manner, the manual handles provide a mechanism by which the positioning of the vertical upright assemblies can be easily and quickly adjusted between their first and second positions in a very small amount of time. 
     A pair of guides are mounted to the base at the front of the frame for linear sliding movement toward and a away from the frame interior. The guides have angled orientations similar to those of the lower inwardly angled positions of the rails of the vertical upright assemblies. The guides at the front of the dispenser assembly are much shorter than the suspended rails of the vertical upright assemblies enabling a forklift truck to lift a stack of pallets over the guides and then deposit the stack of pallets downwardly into the dispenser interior. The guides are each mounted for sliding movement between first and second positions relative to the base of the dispenser. The guides have pins that can be pulled manually out from the guides to disengage the guides from the base enabling them to be moved between their first and second positions and then the pins are dropped into a corresponding hole in the guide slide that holds the guide in its adjusted position. Again, by providing the sliding connections of the guides to the base and the pins that hold the guides in their adjusted positions, the guides can be quickly and easily adjusted between their first and second positions relative to the pallet dispenser base. 
     The pallet dispenser assembly described above provides quick and easy adjustments of the vertical uprights and guides of the pallet dispenser to enable it to receive large or small pallets and quickly adjust to accommodate the pallets so that the pallets are properly oriented relative to a conveyor with which the dispenser is used prior to the dispenser assembly dispensing the pallet onto the conveyor. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further features of the invention are revealed in the following detailed description of the preferred embodiment of the invention and in the drawing figures wherein: 
     FIG. 1 is a front elevation view of the pallet dispenser of the assembly; 
     FIG. 2 is a left side elevation view of the pallet dispenser of the invention; 
     FIG. 3 is a top plan view of the base of the pallet dispenser with the frame removed; 
     FIGS. 4A and 4B show relative positions of the manual handle and one of the rails of a vertical upright assembly of the invention when in their first and second adjusted position; 
     FIGS. 5A and 5B show the relative positions of a manual handle and the rails of one of the vertical upright assemblies when moved between their first and second positions; and 
     FIG. 6 is a partial side elevation view of one of the guides of the dispenser assembly. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIGS. 1 through 3 shows the pallet dispenser  12  of the present invention. The pallet dispenser is basically comprised of a base  14  at the bottom of the dispenser which supports a vertical stack of pallets placed in the dispenser, for example by a forklift truck, and a frame  16  mounted on the top of the base that receives the vertical stack of pallets in its interior. Much of the construction of the base  14  and the frame  16  of the invention is employed in prior art pallet dispensers and these known structural features will be described generally. In the preferred embodiment both the base  14  and the frame  16  are primarily constructed of metal parts to provide strength and rigidity to the pallet dispenser enabling it to accommodate a large vertical stack of pallets. 
     The base  14  is shown from its top in FIG. 3 with the frame  16  removed for clarity. The base  14  is constructed in a rectangular configuration that is larger than the largest pallet to be received by the pallet dispenser. As seen in FIGS. 1 and 2, the base  14  has a vertical height sufficient to accommodate the end of a conveyor (not shown) in the base interior  18  where the conveyor will receive a pallet dispensed by the dispenser. The base of this example of a pallet dispenser is comprised of a front  22  and left  24  and right  26  side walls. The back of a base is left open to accommodate the conveyor (not shown). On the top of the base are four cross beams that define the bottom of the frame  16 . These include a front cross beam  32 , a left side cross beam  34 , a right side cross beam  36  and a rear cross beam  38 . 
     Mounted on the bottom cross beams of the frame are the actuators of the pallet dispenser. Four actuators are employed on the pallet dispenser and each has basically the same construction. The actuators include actuator arms  42  that are mounted in pairs by vertical pivot connections  44  to the opposite bottom left and right cross beams  34 ,  36  of the frame. Each of the actuator arms  42  is constructed like a bell crank and is connected to a piston/cylinder actuator  46  on one side of its pivot connection  44 . The actuator arms  42  extend outwardly toward the base interior  18  when the piston/cylinder actuators  46  are retracted and are pivoted through an arc and extend substantially parallel with the piston/cylinder actuators when the actuators are extended. Each actuator arm  42  is constructed with a first part  48  and a second part  52  that are connected together for linear sliding movement of the two parts relative to each other. For example, the arm second parts  52  are formed with a groove having an inverted T-shape and the arm first parts  48  are formed with a complementary configuration that is received in the groove of the second part. This enables the arm first parts  48  to slide relative to the arm second parts  52  between at least first and second adjusted lengths of the actuator arms  42 . In FIG. 3 the arms are shown adjusted to their first lengths. Adjusting the arms to their second lengths involves sliding the arm first part  48  through its sliding connection with the arm second part  52  provided by the groove in the second part. The top surfaces of the arm&#39;s first parts  48  are provided with holes  54  and the arm&#39;s second parts are provided with spring biased pin detents  56  that can be manually retracted from the holes  54  of the second parts  52  to enable the first parts  48  to be manually slid into the second parts to their second adjusted position. Releasing the detent pin  56  causes it to be received in one of the adjustment holes  54  of the arm&#39;s first parts securing the arm in its second, shorter adjusted length. In this manner, the actuator arms  42  can be quickly and easily adjusted in length to accommodate or support smaller pallets in their first, longer adjusted lengths shown in FIG. 3 or to accommodate or support larger pallets in their second, shorter adjusted lengths. 
     The frame  16  also includes columns  62  that extend upwardly from the bottom cross beams of the frame to the top cross beams of the frame. The top cross beams include left  66  and right  68  cross beams and a rear cross beam  72 . The frame also includes gussets and cross braces to add to the strength and rigidity of the frame, but to simplify the drawing figures only the four corner columns and the three top cross beams are shown in the drawings. The columns and cross beams define the interior  74  of the frame that is dimensioned sufficiently large to receive a vertical stack of skewed or misaligned large pallets therein. Supported on the top cross beams at the top of the dispenser frame is a left side pivot shaft  76 , a right side pivot shaft  78  and a rear pivot shaft  82 . Suspended for pivoting movement from the three pivot shafts are three vertical upright assemblies including a left side assembly  84 , a right side assembly  86  and a rear assembly  88 . Each of the vertical upright assemblies is substantially the same and therefore only the left side vertical upright assembly  84  will be described in detail. 
     The left side vertical upright assembly  84  is comprised of a pair of rails  92  that are suspended from pivot connections  94  at the top ends of the rails from the left side pivot shaft  76  at the top of the frame. The pivot connections  94  could be provided by bearings or bushing connections between the rails and the pivot shaft or, as in this embodiment, can be provided by merely a round, tubular member  96  through which the pivot shaft  76  extends. Spacers or collars could be mounted on opposite sides of the round, tubular member  96  on the pivot shaft  76  to maintain the vertical upright assembly  84  in its position axially on the shaft. Each of the rails  92  are preferably an L-shaped or T-shaped cross section with a flat surface facing toward the interior  74  of the frame. This provides a smooth sliding surface for pallets stacked in the frame interior as they are dispensed vertically downward through the frame as will be described. The bottom ends of the rails  92  are formed with inwardly angled portions  102  as shown in FIGS. 4A and 4B. At the bottommost ends of the rails they are first formed with flats  104  and then outwardly angled portions  106 . In the area of the inwardly angled portion  102 , the rail flat  104  and the outwardly angled portion  106 , the guide rail is reinforced with several metal plates  108  that define a vertical slot  112  behind the inwardly angled portion  102  of the guide rail. The slot  112  is employed in pivoting the guide rails  92  about their pivot connections to the pivot shafts  76 ,  78 ,  82  to move the guide rails between first and second adjusted positions relative to the frame interior  74  as will be explained. 
     Operatively connecting the frame bottom cross beams at the rear  38  and left  34  and right  36  sides of the frame are manual pivot handle assemblies  114 ,  116 ,  118 . Each of the manual handle assemblies is substantially the same and therefore only the left side manual handle assembly  116  will be described in detail. The left side manual handle assembly  116  is shown in FIGS. 3 through 5. It is comprised of two horizontally oriented stub shafts  122  at its opposite ends that are mounted by bearings  124  to the left side bottom cross beam  34  of the frame. The stub shafts  122  have a coaxial center axis and the bushings  124  mount the shafts for rotation about the horizontal center axis of the shaft. Spacers  126  are secured to each of the stub shafts  122  and a rod  128  is secured to the spacers at its opposite ends. The rod  128  passes through the vertical slots  112  of the pair of rails  92  of the left side vertical upright assembly  84 . A hand hold  132  comprised of a plate with two hand openings  134  as secured to the rod  128  between the rails  92  of the left side vertical upright assembly. The pair of bearings  124  mount the manual handle assembly  116  to the bottom left cross beam  34  of the frame for pivoting movement of the handle assembly through an arc over the stub shafts  122  between first and second positions of the handle assembly. The operative connections between the handle assemblies  114 ,  116 ,  118  and their respective vertical upright assemblies  88 ,  84 ,  86  causes the upright assemblies to move between their first and second positions relative to the frame interior  74  in response to the handle assemblies being moved between their first and second positions as will be explained. 
     FIGS. 1,  3  and  6  show additional upright assemblies  136  that are mounted to the bottom front cross beam  32  of the frame. These additional upright assemblies  136  are basically constructed as guides  138  having angled orientations that angle inwardly similar to the inwardly angled portions  102  of the first through third vertical upright assemblies. The angled guides  138  provide smooth surfaces for pallets in a vertical stack of pallets in the frame interior  74  to slide downwardly against. They are connected by several reinforcing plates  140  to slide blocks  142  that have an inverted T-shape similar to that of the actuator arm first parts  48 . The slide blocks  142  are received for sliding movement in complementary inverted T-shaped grooves  144  formed in base members  146  of the guide assemblies that are mounted to the front bottom cross beam  32  of the frame. This connection between the slide blocks  142  and the guide bases  146  enables the blocks and their attached guides  138  to slide, linearly toward and away from the frame interior  74  between first and second adjusted positions of the guides relative to the frame interior. Pins  148  are mounted for upward and downward movement in the slide blocks  142  with the upward movement being limited by a stop  152  mounted to the top of the slide block. Holes  154  complementary to the pins  148  are provided in the bottom of the slot  144 . The pin holes  154  receive the pins  148  when the guides  138  are moved to their first and second adjusted positions relative to the frame interior  74  to hold the guides in their adjusted positions. 
     FIGS. 1 and 2 show the vertical upright assemblies  84 ,  86 ,  88  and the guides  138  in their second adjusted positions relative to the frame interior  74 . In these positions the horizontal spacing between the rail flats  104  of the uprights and the guides  138  is set to properly orient a large pallet, i.e., a pallet of 56 inches by 44 inches, loaded into the pallet dispenser interior  74  by a fork lift prior to the pallet being dispensed by the pallet dispenser. Thus, the spacing between the rail flats  104  of the left and right upright assemblies  84 ,  86  is slightly larger than 56 inches. Also, the horizontal space between the rail flats  104  of the rear upright assembly  88  and the guides  138  at the front of the frame is slightly larger than 44 inches. With the vertical upright assemblies  84 ,  86 ,  88  and the guides  138  adjusted to their second relative positions to the frame shown in FIGS. 1 and 2, the pallet dispenser is adjusted to receive a vertical stack of large pallets and to properly orient pallets at the bottom of the stack as they are dispensed through the pallet dispenser and prior to their being deposited onto a conveyor. 
     To adjust the pallet dispenser vertical upright assemblies and guides from their second positions shown in FIGS. 1 and 2 to their first positions for dispensing smaller pallets, the manual handle assemblies  114 ,  116 ,  118  are moved from their second positions shown in FIG.  4 B and FIG. 5B to their first positions shown in FIGS. 4A and 5A. The manual handle assemblies are moved by gripping the hand openings  134  of the hand holes  132  and then rotating the handle assembly through an arc segment around the center horizontal axis of the stub shafts  122 . This causes the rods  128  of the handle assemblies to move through an arc over the stub shafts  122  and slide along the lengths of the slots  112  of the upright assemblies  84 ,  86 ,  88 . This in turn causes the upright assemblies to pivot about their pivot connections  94  inwardly toward the frame interior  74  to their first positions in the frame interior. When moved to their first positions the rail flats  104  of the left  84  and right  86  vertical upright assemblies are positioned horizontally apart slightly larger than the 48 inches of a small, 48×40 inch pallet. In addition, the pins  148  of the guides  138  at the front of the dispenser base are pulled upwardly from their pin holes  154  and the guides are slid inwardly toward the frame interior  74  to their first positions where the pins  148  will align with the pin holes  154  that correspond to the guide first positions. The pins are dropped into these pin holes securing the guides in place. With the guides  138  adjusted to their first positions and the rear vertical upright assembly  88  previously adjusted to its first position the spacing between the flats  104  of the rear vertical upright assembly and the guides  138  is slightly larger than the 40 inch dimension of the smaller pallet. 
     In the manner discussed above, the vertical upright assemblies and the guides of the pallet dispenser can be quickly and easily manually adjusted between their first and second positions relative to the dispenser frame  16  to accommodate a stack of small or large pallets to be dispensed by the dispenser without appreciable downtime of the pallet dispenser or the conveyor system with which it is used. In addition, the actuator arms  42  of the dispenser can be quickly and easily manually adjusted between their first and second lengths to accommodate a vertical stack of small or large pallets to be dispensed by the dispenser. 
     While the present invention has been described by reference to a specific embodiment, it should be understood that modifications and variations of the invention may be constructed without departing from the scope of the invention defined in the following claims.