BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings which illustrate the preferred embodiments and the best modes presently contemplated for carrying out the present invention:
FIG. 1 is a side view of a depalletizer configured according to a preferred embodiment of the present invention showing loaded pallets in the load receiving and load separating sections;
FIG. 2 is a side view of the depalletizer of FIG. 1 showing the stack of articles clamped in the load separating section and the pallet separated from the stack;
FIG. 3 is a side view of the depalletizer of FIG. 2 showing the empty pallet moved to the pallet transfer section and the transfer mechanism raised to the bottom layer of the stack to support the stack with the stack unclamped;
FIG. 4 is a side view of the depalletizer of FIG. 3 showing the transfer mechanism lowered and the stack of articles reclamped above the bottom layer of articles;
FIG. 5 is a side view of the depalletizer of FIG. 4 showing the transfer mechanism further lowered to separate the bottom layer of the stack from the rest of the stack;
FIG. 6 is a side view of the depalletizer of FIG. 5 showing the separated layer of the stack conveyed away and the remaining layers of the stack supported above the clamped layer;
FIG. 7 is a side view of the depalletizer of FIG. 6 showing the stack unclamped and the transfer mechanism raised to the bottom of the remaining stack to repeat the process of removing a layer of articles from the stack;
FIG. 8 is a top view of the depalletizer of the present invention showing a loaded pallet in the load receiving section, a stack of articles in the load separating section, an empty pallet in the pallet transfer section and a separated layer of articles in the article transfer section;
FIG. 9 is a top view of the transfer mechanism utilized with the depalletizer of the present invention;
FIG. 10 is a side view of the transfer mechanism of FIG. 9 showing the chain drive mechanism in the up or raised position;
FIG. 11 is an end view of the transfer mechanism of FIG. 10;
FIG. 12 is a side view of the transfer mechanism of FIG. 9 showing the chain drive mechanism in the down or lowered position;
FIG. 13 is an end view of the transfer mechanism of FIG. 12; and
FIG. 14 is a flow chart summarizing the steps of the depalletizing process for the depalletizer of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to the figures where like elements have been given like numerical designations to facilitate the reader's understanding of the present invention, the preferred embodiments of the present invention are set forth below. The enclosed figures and drawings are merely illustrative of a preferred embodiment and represents one of several different ways of configuring the present invention. Although specific components, materials, configurations and uses are illustrated, it should be understood that a number of variations to the components and to the configuration of those components described herein and in the accompanying figures can be made without changing the scope and function of the invention set forth herein. For instance, although the figures and description provided herein are primarily described as being utilized with crates on a standard pallet, those skilled in the art will readily understand that this is merely for purposes of simplifying the present disclosure and that the present invention is not so limited, as the present invention is equally applicable for use with a variety of different types of articles and load bearing structures.
An off-the-bottom depalletizer that is manufactured out of the components and configured pursuant to a preferred embodiment of the present invention is shown generally as 10 in FIGS. 1 through 8. Depalletizer 10 is configured to receive a pallet 12 having a plurality of articles 14 configured as a stack 16 of such articles 14 having at least one layer 18. Typically, the stack 16 will have a plurality of layers 18 comprising a bottom layer 20, top layer 22 and a plurality of intermediate layers 24 therebetween. Collectively, the pallet 12 having a stack 16 of articles 14 thereon is referred to as a loaded pallet 26. As best shown in FIG. 8, depalletizer 10 of the present invention generally comprises a load receiving section 28 that receives the loaded pallet 26, a load separating section 30 that separates the pallet 12 from stack 16 and the layers 18 of articles 14 from stack 16, a pallet transfer section 32 that receives the unloaded or depalletized pallet 12 and transports it away, and an article transfer section 34 that receives the articles 14 removed from stack 16 and transports them away for further handling and/or processing. As will be explained in more detail below, the loaded pallet 26 is received at the load receiving section 28 and transferred to separating section 30 where pallet 12 is removed from stack 16 and, in an step-wise or incremental manner, lower layer 20 is removed from stack 16. Loaded pallet 26 moves into and through depalletizer 10 so that the individual articles 14 can be efficiently and quickly removed therefrom and pallet 12 emptied.
Load receiving section 28 has a pallet infeed conveyor 36 comprising an infeed conveyor structure 38 having a plurality of rollers 40 supported thereby, as best shown in FIG. 8. Infeed conveyor structure 38 is supported in spaced apart relation above the floor of the facility or ground by one or more support legs 42. A motor 44 is supported by infeed conveyor structure 38 and operatively connected to the rollers 40 such that when a loaded pallet 26 is placed on pallet infeed conveyor 36 the loaded pallet 26 will be conveyed to the adjacent load separating section 30. As will be readily apparent to those skilled in the art, various other conveying mechanisms or other mechanisms can be utilized to deliver loaded pallet 26 to load separating section 30. A continuous feed conveying system is preferred so that as soon as the loaded pallet 26 is depalletized in the load separating section 30, another loaded pallet 26 can be received therein for depalletizing.
As shown in FIGS. 1 through 8, load receiving section 30 comprises a frame 46 having a plurality of frame members 48, a clamping mechanism 50 supported by the frame 46 and configured to clamp onto one or more layers 18 of stack 16 and support the layers 18 above, and a transfer mechanism 52, also supported by frame 46, configured to support the loaded pallet 26 or stack 16 and to separate pallet 12 from stack 16 and convey it to pallet transfer section 32 and remove bottom layer 20 from stack 16 and transfer the articles 14 in bottom layer 20 to article transfer section 34. The frame members 48 of frame 46 define a separating chamber 54 in load receiving section 30 where the pallet 12 is separated from the stack 16 and the bottom layer 20 (which is always the lowermost layer in stack 16) is also separated from stack 16.
Clamping mechanism 50 is configured to clamp or squeeze against one or more layers 18 of stack 16 to hold stack 16 in a suspended position, such as shown in FIGS. 2 and 6. As such, clamping mechanism 50 must sufficiently clamp against layers 18 so that they do not fall when, as explained below, the pallet 12 or bottom layer 20 is removed. As a result, depalletizer 10 of the present invention can only be utilized with those articles 14 that have sufficient structural integrity that they form a layer 18 which can be tightly clamped and which is strong enough to support the layers, such as the top 22 and intermediate 24 layers, above the clamped layer. For example, crates or other containers commonly utilized to store and transport fresh fruit and vegetables generally have the characteristics that make them suitable for depalletizer 10 of the present invention. In a preferred embodiment, clamping mechanism 50 comprises a plurality of clamp members 56 operatively connected to clamp drive mechanism comprising a plurality of air cylinders 60 and pneumatic valves that are configured to move clamp members 56 between their open position 62, as shown in FIGS. 1, 3, 7 and 8, and their closed or clamping position 64, as shown in FIGS. 2 and 4 through 6. As well known in the art, a variety of different electrical, mechanical, pneumatic and other systems can be utilized as the clamp drive mechanism for clamping mechanism 50. Clamping mechanism 50 is configured to clamp one or more layers 18 of stack 16, including at least the bottom layer 20. In the embodiment shown in the figures, clamp members 56 of clamping mechanism 50 are configured to engage the bottom layer 20 and the second layer above the bottom layer 20, which are also referred to as the lower clamped layer, shown as 20 and the upper clamped layer 66. As explained in more detail below, the bottom layer 20 of stack 16 alternates between being a clamped layer and the bottom layer below the lower clamped layer for removal. Depending on the weight and structural integrity of the articles 14, it may only be necessary to clamp the bottom layer 20, if it is strong enough to support the above layers 18, or it may be necessary to clamp more than just two layers 18 in stack 16.
Clamping mechanism 50 can operate in a variety of different configurations. For instance, in one configuration all clamp members 56 can be operated to uniformly squeeze against the lower clamped layer 20 and the upper clamped layer 66. In a preferred embodiment, however, the clamp members 56 on the right and top sides of the stack 16 (relative to the bottom of the figure) are configured to move inwardly against stack 16 to square it up, thereby requiring these clamp members 56 to move only relatively small amount (i.e., one inch) to abut stack 16. In this embodiment, the clamp members 56 on the left and bottom sides of stack 16 move inwardly against stack 16 a distance sufficient to apply the desired amount of force to the one or more layers 18 to be clamped. The force imparted by these clamp members 56 (i.e., those on the left and bottom sides) is countered by the opposite clamp members 56 (i.e., those on the right and top sides) to engage one or more layers 18 of stack 16 therebetween. As explained in more detail below, clamping mechanism 50 is operated to allow the separation of pallet 12 from stack 16 and then bottom layer 20 from stack 16.
Air cylinders 58 are utilized to open and close doors 68 at the entrance to separating chamber 54 that is between load receiving section 28 and load separating section 30, as best shown in FIG. 8. Doors 68 support the clamp members 56 on that side of the separating chamber 54 and are utilized to allow the loaded pallet 26 to enter into the separating chamber 54. In the embodiment shown, a pair of doors 68 are utilized, each supporting a clamp member 56 and associated valving. The preferred embodiment also includes position monitoring device 70, such as an electric eye or the like, that is configured to detect when a loaded pallet 26 or a stack 16 is in separating chamber 54 and then send a signal to close doors 68. The position monitoring device 70 closes the doors 68 after loaded pallet 26 is received in separating chamber 54 and keeps the doors 68 closed until the last layer 18, which will be top layer 22, is removed from separating chamber 54 to the article transfer section 30, at which time doors 68 are opened to allow a new loaded pallet 26 to be received in separating chamber 54 for depalletizing.
Transfer mechanism 52 is configured to separate the pallet 12 from the stack 16 of articles 14 and then to move the bottom layer 20 of stack 16 to article transfer section 34. In the preferred embodiment, as best shown in FIGS. 9 through 13, transfer mechanism 52 comprises a transfer support structure 72 having a support surface 74 and a discharging mechanism 75 configured to discharge the pallet 12 and the bottom layer 20 from load separating section 30, as explained below. Support surface 74 is defined, alternatively depending on the desired action by depalletizer 10, by a layer conveyor 76 or a pallet conveyor 78 that comprise discharging mechanism 75. In a preferred embodiment, as shown in the figures, layer conveyor 76 is a roller conveyor and pallet conveyor 78 is a chain conveyor. As explained in more detail below, transfer support structure 72 is moved up and down to contact either the lower surface of pallet 12 or the lower surface of bottom layer 20 to separate and move these components, using discharging mechanism 75, to their respective locations (i.e., pallet transfer section 32 or article transfer section 34). In addition, the pallet conveyor 78 is moved up and down relative to the layer conveyor 76 depending on whether contact is to be made with pallet 12 or bottom layer 20. These components are supported by a frame 80. As well known in the art, the roller conveyor of layer conveyor 76 comprises a plurality of rollers 82 and associated motor(s) and drive assemblies to rotate rollers 82 and the chain conveyor of pallet conveyor 78 comprises a one or more chains 84 and associated motor(s), such as the electric motor 86 shown in FIGS. 10 and 12, and drive assemblies to drive chains 84. To achieve the desired raising and lowering of support structure 72 and pallet conveyor 78, as described below, transfer mechanism 52 also comprises a structure moving mechanism 88, such as the pneumatic system shown. As best shown in FIGS. 10 and 12, the pneumatic system of structure moving mechanism 88 can comprises one or more first air cylinders 90 (two of which are shown in FIGS. 11 and 13) configured to raise and lower the entire support structure 72 of transfer mechanism 52, one or more second air cylinders 92 (two of which are shown in FIGS. 10 and 12) to raise and lower the pallet conveyor 78 relative to the layer conveyor 76, and one or more third air cylinders 94 (two of which are shown in FIGS. 10 and 12) to raise and lower the entire support structure 72 a relatively small amount to allow clearance for the pallet 12 to move to pallet transfer section 32 and the bottom layer 20 of stack 16 to move to article transfer section 34. The operation of the various air cylinders 90, 92 and 94 of pneumatic system 88 are explained below.
Pallet transfer section 32, shown in FIGS. 1 through 8, is utilized to receive an depalletized pallet 12 and transfer it away for storage or further use (i.e., to receive articles thereon). In a preferred embodiment, pallet transfer section 32 comprises a discharge chain conveyor 96 supported by a transfer section frame 98 and comprising a chain 100. Discharge chain conveyor 96 is fixed, meaning it does not move up and down, but it is positioned at a level lower than the level of pallet infeed conveyor 36 for ease of operation with regard to the removal of pallet 12 after it has been separated from stack 16 by transfer mechanism 52. In one embodiment, discharge chain conveyor 96 is two inches lower than pallet infeed conveyor 36. As explained below, transfer mechanism 52 lowers support structure 72, using third air cylinder 94, to the level of the discharge chain conveyor 96.
Article transfer section 34, shown in FIG. 8, is utilized to receive articles 14 removed from the stack 16, typically in a layer 18, by transfer mechanism 52. In a preferred embodiment, article transfer section 34 comprises an article take-away conveyor 102 that is configured to receive an entire layer 18 of articles 14 from stack 16, a pair of stops 104 configured to selectively stop one of the rows of the layer 18 and let the other proceed for further processing and a chute 106 for directing the row of articles 14 in the desired direction. For use with crates having material therein, the articles 14 would proceed to a dump station (not shown) that dumps the materials out of the articles 14 and then to a stacking station that stacks the articles for reuse. If two dump stations are utilized, it will generally not be necessary to provide stops 104 as both rows of articles 14 can proceed to the dump stations. In a preferred embodiment, article take-away conveyor 102 is fixed at the same height as the discharge chain conveyor 96, which is slightly lower (i.e., two inches) than the pallet infeed conveyor 36 so that the bottom row 20 of stack 16 can be separated from stack 16 and the more easily transferred to article take-away conveyor 102. As explained below, transfer mechanism 52 lowers support structure 72, using third air cylinder 94, to the level of the article take-away conveyor 102.
The operation of the depalletizer 10 of the present invention is shown sequentially in FIGS. 1 through 7. In FIG. 1, the loaded pallet 26 is received in load receiving section 28 on pallet infeed conveyor 36, which conveys loaded pallet 26 to the load separating section 30. If there is not a loaded pallet 26 or stack 16 in separating chamber 54, as determined by position monitoring device 70, then the doors 68 are open to allow a loaded pallet 26 to be received in the separating chamber 54, as shown in FIG. 1, and then the doors 68 are closed. Prior to receiving loaded pallet 26 in separating chamber 54, first air cylinder 90 of pneumatic system 88 places the support surface 74 of support structure 72 approximately at the same level, or slightly below, as the pallet infeed conveyor 36, with the pallet conveyor 78 defining support surface 74, as shown in FIGS. 10 and 12 with chain 84 in its up position. In FIG. 1, the bottom of pallet 12 is abuts and is supported by the pallet conveyor 78 of support structure 72. With loaded pallet 26 supported by support structure 72, the clamping mechanism 50 is activated so that clamp members 56 are engaged to move to their clamping position 64, as shown in FIG. 2, to abut a portion of stack 16. In the embodiment of FIG. 2, clamp members 56 engage the bottom layer 20 of stack 16 and the upper clamped layer 66. With stack 16 secured in place by clamping mechanism 50, third air cylinder 94 is activated to lower support structure 72 to a lowered position 108, which at this point in the process is the set amount (i.e., two inches) such that the bottom of pallet 12, which moves down with support structure 72 because it is not held in place by clamping mechanism 50, is substantially aligned with discharge conveyor 96. The pallet conveyor 78 of support structure 72 is activated to move pallet 12 to the discharge conveyor 96, as shown in FIG. 3, so that pallet 12 can be transferred for storage or reuse. Once pallet 12 is removed, second air cylinder 92 is activated to lower pallet conveyor 78 below the layer conveyor 76 such that the roller conveyor forms support surface 74. As also shown in FIG. 3, support structure 72 is raised by first air cylinder 90 to its raised position 110 such that support surface 74, defined by the layer conveyor 76, abuts the lower surface of bottom layer 20. With support structure 72 in its raised position 110 below bottom layer 20, the clamping mechanism 50 is activated to move clamp members 56 to their open position 62, as shown in FIG. 3, to transfer stack 16 to support structure 72.
In FIG. 4, the support structure 72 is shown having been lowered to a lowered position 108, in this case approximately the height of one layer 18 of articles 14 by first air cylinder 90, thereby lowering stack 16, so that the clamp members 56 of clamping mechanism 50 will engage the layer 18 above the bottom layer 20 and the layer 18 two layers above, making these layers the lower clamped layer 20 and upper clamped layer 66, respectively. With the clamp members 56 in their clamping position 64, thereby transferring the weight of stack 16 above the bottom layer 20 to the clamping mechanism 50, third air cylinder 94 is activated to lower support structure 72 to another lowered position 108, which is the specified amount (i.e., two inches), as shown in FIG. 5, to substantially align layer conveyor 76 of support surface 74 with the article take-away conveyor 102. The activation of layer conveyor 76 transfers the bottom layer 20 to article take-away conveyor 102, as shown in FIG. 8, to leave the remaining portion of stack 16 being supported by the clamping mechanism 50 in spaced apart relation to the support surface 74 of support structure 72, as shown in FIG. 6. First air cylinder 90 is activated to move support structure 72 upward to its raised position 110 so the support surface 74 will abut against the lower surface of bottom layer 20, as shown in FIG. 7. As also shown in FIG. 7, clamping mechanism 50 moves clamp members 56 to their open position 62 to transfer the stack 16 to support structure 72. Once the stack 16 is on support structure 72, the process described above in conjunction with that shown in FIGS. 4 through 7 is repeated until the top layer 22 of stack 16 is transferred to article take-away conveyor 102. Once the position monitoring device 70 determines that separating chamber 54 is empty, doors 68 will be activated to open and allow another loaded pallet 26 to move into separating chamber 54 so that it can be depalletized as described above. Using the depalletizer 10 and method of the present invention, the inventor has achieved depalletizing speeds of 3,500 boxes an hour.
The method of the depalletizing according to the present invention using depalletizer 10 is summarized in the flow chart of FIG. 14. As shown therein, depalletizing loaded pallet 26 comprises the following steps (1) receiving a loaded pallet 26 at a load receiving section 28; (2) transporting the loaded pallet 26 to a support structure 72 in a load separating section 30; (3) clamping the stack 16 of articles 14 with a clamping mechanism 50 at least at bottom layer 20; (4) lowering the support structure 72 to separate the pallet 12 from the stack 16 of articles 14; (5) transporting away the empty pallet 12 to a discharge conveyor 96; (6) raising the support structure 72 to the lower surface of the bottom layer 20 to support the stack 16 thereon; (7) releasing the clamping mechanism 50 to transfer stack 16 to support structure 72; (8) lowering support structure 72 and stack 16 a distance equal to the height of one layer 18 of stack 16; (9) reclamping stack 16 at the layer immediately above bottom layer 20; (10) lowering support structure 72 to separate bottom layer 20 from the remaining portion of stack 16; (11) removing bottom layer 20 to article take-away conveyor 102; (12) repeating the raising, releasing, lowering, reclamping, lowering and removing steps of steps 6 through 11 until entire stack 16 of articles 14 is depalletized; and (13) repeating steps 1 through 12 for a new loaded pallet 26 until all such loaded pallets 26 have been depalletized.
While there are shown and described herein specific forms of the invention, it will be readily apparent to those skilled in the art that the invention is not so limited, but is susceptible to various modifications and rearrangements in design and materials without departing from the spirit and scope of the invention. In particular, it should be noted that the present invention is subject to modification with regard to any dimensional relationships set forth herein and modifications in assembly, materials, size, shape, and use. For instance, there are numerous components described herein that can be replaced with equivalent functioning components to accomplish the objectives of the present invention.
Patent Application
20080014074
