Corrugated pallet shipping method

Abstract

A shipping method includes the steps of receiving stacks of flat die cut corrugated paperboard blanks from a corrugator or sheet plant; loading the stacks of blanks into a pallet assembly machine; folding the blanks together in the assembly machine to produce a corrugated paperboard pallet; and providing the pallets for shipping items to a receiver. The assembly machine folds the blanks using intermittent motion of the blanks through multiple folding sections in the assembly machine. The sections operate by positioning, clamping and folding the blanks using levers that are supported by rotary bearings and driven by pinned end mounted pneumatic cylinders. The assembly machine overcomes misalignment and shifting of the stacks of blanks by picking up single blanks from the top of the stacks using vacuum, and adjusting alignment of the blanks after being picked up but prior to being fed into the first folding section of the assembly machine.

Claims

1. A shipping method comprising: receiving stacks of flat die cut corrugated material blanks from a corrugator or sheet plant; loading said stacks of said blanks into a pallet assembly machine; said pallet assembly machine folding said blanks together and producing a corrugated material pallet; providing said corrugated material pallets for shipping items to a receiver; said pallet assembly machine folding said blanks using intermittent motion of said blanks and said pallet assembly machine comprising multiple folding sections wherein said sections operate by positioning, clamping and folding said blanks; said pallet assembly machine overcoming misalignment and shifting of said stacks of said blanks by picking up said blanks from the top of said stacks using vacuum and adjusting alignment of said blanks after picked up but prior to being fed into the first folding section of said pallet assembly machine.

2. A shipping method defined in claim 1 wherein: said stacks of said blanks comprising between 80 and 280 blanks and said loading into said pallet assembly machine being done with a fork lift.

3. A shipping method defined in claim 1 wherein: said pallet assembly machine being located at a shipper and providing corrugated material pallets to a palletizer based on a signal from said palletizer.

4. A shipping method defined in claim 1 wherein: said adjusting alignment of said blanks being accomplished by said pallet assembly machine providing support for said blanks from at least two sides, releasing said vacuum and shifting said blanks laterally.

5. A shipping method defined in claim 1 wherein: said folding sections having a total combined floor area of less than 500 square feet.

6. A shipping method defined in claim 1 wherein: said folding of said blanks using levers that are supported by rotary bearings and driven by pinned end mounted pneumatic cylinders.

7. A shipping method defined in claim 1 wherein: said pallet assembly machine folding said blanks using mechanical stops for the machine motions in conjunction with a computer providing time based open loop control to solenoid valves that actuate said folding.

8. A shipping method defined in claim 1 wherein: said corrugated material pallets being constructed from two different blanks which form the pallet top and the pallet bottom, and said pallet assembly machine comprising three sections that fold said pallet top, fold said pallet bottom, and fold said pallet top and said pallet bottom together.

9. A shipping method defined in claim 1 wherein: said pallet assembly machine folding said blanks to form at least one rib extending out of plane of each of said blanks, said ribs of said top and bottom blanks extending perpendicular to each other and having aligned notches facing each other, said machine pressing said top and bottom blanks together so that said notches interlock and maintain said ribs in closed position and producing a corrugated material pallet.

10. A shipping method comprising: receiving stacks of top and bottom flat die cut corrugated material blanks from a corrugator or sheet plant; loading said stacks of said blanks into a pallet assembly machine; said pallet assembly machine folding said top and bottom blanks together and producing a corrugated material pallet; providing said corrugated material pallets for shipping items to a receiver; said pallet assembly machine folding said blanks using intermittent motion of said blanks and said pallet assembly machine comprising multiple folding sections to form said top and bottom blanks and assemble said folded top and bottom blanks together wherein said sections operate by positioning, clamping and folding said blanks; said folding of said blanks accomplished using levers which are supported by rotary bearings and driven by pinned end mounted pneumatic cylinders; said pallet assembly machine folding said blanks using mechanical stops for motions of said top and bottom blanks in conjunction with a computer providing time based open loop control to solenoid valves that actuate said folding.

11. A shipping method defined in claim 10 wherein: said pallet assembly machine overcoming misalignment and shifting of said stacks of said blanks by picking up said blanks from the top of said stacks using vacuum and adjusting alignment of said blanks after being picked up but prior to being fed into a first folding section of said pallet assembly machine.

12. A shipping method defined in claim 11 wherein: said adjusting alignment of said blanks being accomplished by said pallet assembly machine providing support for said blanks from at least two sides, releasing said vacuum and shifting said blanks laterally.

13. A shipping method defined in claim 10 wherein: said folding sections having a total combined floor area of less than 500 square feet.

14. A shipping method defined in claim 10 wherein: said stacks of said blanks being shipped to the location of said pallet assembly machine on slip sheets.

15. A shipping method as defined in claim 10, wherein said pallet assembly machine folding said blanks to form at least one rib extending out of plane of each of said blanks, said ribs of said top and bottom blanks extending perpendicular to each other and having aligned notches facing each other, said machine pressing said top and bottom blanks together so that said notches interlock and maintain said ribs in closed position and producing a corrugated material pallet.

16. A shipping method defined in claim 10 wherein: said pallet assembly machine being located at a shipper and providing corrugated material pallets to a palletizer based on a signal from said palletizer.

17. A shipping method defined in claim 10 wherein: said stacks of said blanks comprising between 80 and 280 blanks and said loading into said pallet assembly machine being done with a fork lift.

18. A shipping method defined in claim 10 wherein: said corrugated material pallets being constructed from two different blanks which form the pallet top and the pallet bottom, and said pallet assembly machine comprising three sections that fold said pallet top, fold said pallet bottom, and fold said pallet top and said pallet bottom together.

Description

DESCRIPTION OF THE DRAWINGS

(1) The invention and its many advantages and features will become better understood upon reading the following detailed description of the preferred embodiments in conjunction with the following drawings, wherein:

(2) FIG. 1 is a schematic drawing of a completed corrugated paperboard pallet for use in the shipping method in accordance with the invention.

(3) FIG. 2 is a schematic drawing of the corrugated paperboard pallet of FIG. 1 in flat blanks state for use in the shipping method in accordance with the invention.

(4) FIG. 3 is a schematic drawing of the corrugated paperboard pallet of FIG. 1 in folded top and bottom state for use in the shipping method in accordance with the invention.

(5) FIG. 4 is a schematic flow diagram of a corrugated paperboard pallet shipping method in accordance with the invention.

(6) FIG. 5 is a schematic drawing of a corrugated paperboard pallet assembly machine in accordance with the invention.

(7) FIG. 6 is a schematic drawing of the blank loading section of a corrugated paperboard pallet assembly machine in FIG. 5 in accordance with the invention.

(8) FIG. 7 is a schematic diagram of the blank clamping in a folding section of a corrugated paperboard pallet assembly machine in FIG. 5 in accordance with the invention.

(9) FIG. 8 a schematic diagram of the rib folding in a folding section of a corrugated paperboard pallet assembly machine in FIG. 5 in accordance with the invention.

(10) FIG. 9 is a schematic flow diagram of the control and operation of a corrugated paperboard pallet assembly machine in FIG. 5 in accordance with the invention.

(11) FIG. 10 a schematic diagram of a machine process for use with a corrugated paperboard pallet production machine in FIG. 5 in accordance with the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

(12) Turning to the drawings, wherein like reference characters designate identical or corresponding parts, FIG. 4 shows a flow diagram of a corrugated material pallet shipping method in accordance with the invention. The disclosed preferred embodiment uses the machine to produce corrugated paperboard, but other corrugated materials could be used instead. The shipping method 50 comprises a corrugator or sheet plant 51 where corrugated pallet blanks 31, 32 are produced and shipped in stacks to a product shipper 53. The blanks 31, 32, such as those illustrated in FIG. 2, comprise stacks 71, 72 of top and bottom die cut corrugated pallet blanks 31, 32, sent to the product shipper in step 52. The product shipper 53 has a facility with a pallet assembly machine 54 for producing new pallets from corrugated paperboard blanks 31, 32 sent from the corrugator 51, and a palletizer 55 for palletizing products on the assembled pallets 30. The product shipper 53 takes the pallet blanks 31, 32 and utilizes the pallet assembly machine 54 (shown in more detail in FIG. 5) to produce recyclable corrugated pallets 30. The corrugated pallets 30 are loaded by the product shipper 53 utilizing the palletizer 55. The product on corrugated pallet 30 is shipped in step 56 from the product shipper 53 to the product receiver 57. At the product receiver 57, the product on corrugated pallet is unloaded in step 58 and the corrugated pallet is recycled in step 59. There is no need for the product shipper to store pallets to facilitate shipping, nor does the product shipper need a massive facility and infrastructure to produce wood pallets just-in-time. Pallets are made available to the product shipper exactly when needed. Tracking of the pallets after shipping product to the product receiver is also no longer necessary as the pallets are uniquely recycled after one time use

(13) A schematic diagram of a corrugated paperboard pallet assembly machine 54 for use with the shipping method of FIG. 4 is shown in FIG. 5. The pallet assembly machine 54 preferably takes up a minimal amount of space, preferably less than 600 square feet and to accomplish this, discontinuous motion of the corrugated paperboard was surprisingly found to be the solution. Contrary to teaching in the art of corrugated manufacturing, we have found that discontinuous or intermittent motion of corrugated material is desirable in this application. As a downside, the assembly machine requires steps for material registration due to stopping and also increased assembly time. However, we have found that this method can be utilized to dramatically reduce floor space required for the pallet assembly machine in lieu of a significantly shorter assembly time. We have also found that the longer assembly time with discontinuous motion is still adequately short enough to meet the time necessary for palletizing by a downstream palletizer even if up to three palletizers are fed per assembly machine in most cases. The pallet assembly machine 54 takes in top blanks 31 from the stack 71 into a pallet top former 60 and takes in bottom blanks 32 into the pallet bottom former 62 (shown schematically in FIG. 9). Ribs 35, 36 are folded in the blanks top and bottom blanks 31, 32 as shown in FIGS. 7 and 8, and the blanks 31, 32 are joined by nesting the notches 37 in the ribs 35, 36 into each other in a top and bottom joiner 75 which assembles and folds together the pallet tops and pallet bottoms to form finished pallets 30. The pallet assembly machine 54 is operated by a control 161 that comprises a controller 162 and solenoid valves 163. A compressor 164 feeds air under pressure to the control 161 that operates the pallet top former 60, pallet bottom former 62 and pallet top and bottom joiner 55. In one preferred embodiment, the pallet assembly machine 50 comprises open loop pneumatic control for reliability and low costs. In the pallet top former 52 is the initial step of registration 61 to insure proper location and operation on the top blanks 51. In the pallet bottom former 54 is the initial step of registration 63 to insure proper location and operation on the pallet bottom blanks 53. In the top and bottom joiner 55, the initial step is also registration 62.

(14) A schematic diagram of a machine process for use with a corrugated paperboard pallet production machine of FIG. 5 is shown in FIG. 10. The process comprises three sections, the pallet top forming 171 performed by the pallet top former 60, pallet bottom forming 178 performed by the pallet bottom former 62, and the pallet top and bottom joining 185 performed by the pallet top and bottom joiner 64. The three sections 60, 62, 64 perform their respective steps of the process, as shown in FIG. 10, to form a completed pallet 30.

(15) The pallet top former 60 performs the following steps: Step 172picking up the top blank 31 off the top of the stack 71. Step 173 loading the top blank onto taking in the top blank 84, registering the location of the top blank 85, stopping motion of the corrugated blank 86, clamping the top blank 87 and folding the vertically extending members 88 on the top blank. The pallet bottom former comprises the steps of picking up the bottom blank 89, taking in the bottom blank 90, registering the location of the bottom blank 91, stopping motion of the corrugated blank 92, clamping the bottom blank 93 and folding the vertically extending members 94 on the bottom blank. The pallet top and bottom joiner comprises the steps of taking in the pallet top and bottom 95, registering the location of the pallet top and bottom 96, stopping the motion of the corrugated pallet top and bottom 97, clamping the pallet top and bottom together 98, folding the pallet top and bottom together 99 and ejecting the completed pallet to a palletizer 100. After each cycle, the pallet assembly machine repeats the cycle 101 upon signal from the palletizer that a pallet is needed.

(16) A schematic drawing of corrugated paperboard pallet flat blanks for use in the shipping method of FIG. 1 is shown in FIG. 4. The corrugated pallet 110 is formed from two flat die cut corrugated blanks 111, 112. These blanks may be of different corrugation configurations. For instance, we have found that B-C flute is desirable for both with the C side at the pallet top and bottom

(17) A schematic drawing of a corrugated paperboard pallet 110 with folded pallet bottom 111 and folded pallet bottom 112 aligned for compression assembly together is shown in FIG. 5. The pallet bottom 111 has vertically extending ribs 113 and the pallet top 112 has vertically downward extending ribs 114. The top pallet ribs 114 and bottom pallet ribs 113 intersect to form the rigid and reliable pallet load support.

(18) A schematic drawing of completed corrugated paperboard pallet for use in the shipping method of FIG. 1 is shown in FIG. 6. The pallet 110 comprises a pallet bottom 111 and a pallet top 112. Once folded into complete assembly, the pallet 110 preferably has fork holes 115, 116 for entry in all four directions.

(19) A schematic diagram of corrugated paperboard pallet shipping method in accordance with the invention is shown in FIG. 4. The shipping method 50 comprises shipping corrugated paperboard blanks 52 from a corrugator or blank producer 51 to a product shipper 53. Blanks are produced by die cutting corrugated paperboard and this can typically either be done by a corrugator or a sheet plant. The product shipper 53 does both pallet assembly 54 and a palletizing 55. The blanks 52 are loaded into the pallet assembly machine which assembles pallets 54 in response to a signal from the palletizer that palletizes. The palletizer then loads the shipping items or products on to the corrugated paperboard pallet. The product shipper 53 ships product 56 to a product receiver 57. The product receiver 57 unloads 58 the product and recycles 59 the corrugated paperboard.

(20) A schematic drawing of a corrugated paperboard pallet assembly machine in accordance with the invention is shown in FIG. 5. The pallet assembly machine is preferably designed to operate for millions of cycles reliably with little or no maintenance. We have found that a way to accomplish this goal is to utilize rotary bearings, which retain lubrication for life, in conjunction with levers and actuated by pinned end mounted pneumatic cylinders. The pallet assembly machine 70 creates pallets from two stacks of corrugated paperboard blanks 71, 72. The blanks 71, 72 form the pallet top 31 and pallet bottom 32 by being folded in the pallet top folding section 73 and pallet bottom folding section 74 using apparatus shown in FIG. 8 in each of sections 73 and 74 (not shown in FIG. 5 for clarity of illustration.) The pallet top and pallet bottom are then folded together in the joining section 75 to produce a finished pallet. The pallet top folding section 73 and pallet bottom folding section 74 each pick up blanks 71, 72 using vacuum suction cups 76, 77 attached to the feed head frames 89, 90. The blanks 71, 72 are then preferably aligned before being fed into the folding sections 73, 74 to provide for accurate feeding and folding. The feed heads 89, 90 are raised by lift arms 78, 79 that are supported by rotary bearings 80, 81. The arms 78, 79 are driven by pneumatic cylinders 82, 83 that are mounted with pinned ends. Using pinned ends eliminated bending in the pneumatic cylinders and greatly extends cylinder life. An average travel life of 1500 miles can be expected which results in millions of cycles for most cylinders on the pallet assembly machine 70. After the ribs 35, 36 are formed in the pallet top 31 and pallet bottom 32, the pallet top and pallet bottom are moved into the joining section 75. The pallet top 31 and pallet bottom 32 are positioned to align vertically and then are clamped together by upper and lower platens 84 and 85. The lower platen 85 moves vertically by swing arms or levers 86 that are supported by rotary bearings 87 and driven by a pneumatic cylinder 88. After the pallet top 31 and pallet bottom 32 are clamped together, the pallet assembly machine 70 folds the sides and then ejects the completed pallet 30.

(21) To ensure accurate and reliable folding of the corrugated paperboard pallets, the blanks 71, 72 must be fed into the folding sections 73, 74 without jamming and must be positioned accurately. This is despite the fact that the stacks of blanks 71, 72 are not perfectly aligned and typically are shifted during transport. We have found that the most compact and reliable means to accomplish this goal is to pick up blanks from the top of the stacks using vacuum suction cups 76, 77 and then adjust alignment of the blanks after being picked up but prior to being fed into the first folding section of the pallet assembly machine. A schematic elevation of the blank loading section of a corrugated paperboard pallet assembly machine in FIG. 5 in accordance with the invention is shown in FIG. 6. The feed head 89 picks up a blank 31 from the top of the stack of blanks 71. The stack of blanks 71 is preferably shipped on a slip sheet, bottom of stack, and loaded into the pallet assembly machine 70 by use of a fork lift. The fork lift sets the blanks 71 on bank supports 100.

(22) The feed head 89 picks up the blank 31 and supports 101, 102 and 103 are moved under the blank 31. The vacuum 77 is then released such that the blanks rest freely on mechanical supports 101, 102, 103. Side pneumatic cylinders 104, 105 are actuated, which centers and aligns the blank 31 on the supports 101, 102, 103 for proper feeding by a pair of scissor arms (not shown) into the clamp 110, 111 of the first folding section 60, shown in FIG. 8. The first folding section actually resides in section 73, but is shown separately in FIG. 8 for clarity of illustration.

(23) A schematic elevation of the blank clamping in a folding section of a corrugated paperboard pallet assembly machine in FIG. 5 in accordance with the invention is shown in FIG. 7. The blank 31 is moved/into the fold section 73, then clamped between upper and lower clamp bars 110, 111.

(24) The rib folding in a folding section of a corrugated paperboard pallet assembly machine in FIG. 5 in accordance with the invention is shown in FIG. 8. The rib folding is done after the blank is clamped. The rib folding on the top blank 31 is performed by the apparatus shown in FIG. 8 and located in section 73 of the machine shown in FIG. 5. The rib folding on the bottom blank 32 is performed by the apparatus shown in FIG. 8 and located in section 74 of the machine shown in FIG. 5.

(25) Rib folding is initiated by outer side rollers 131, 133 mounted on levers 132, 134 that are moved inward to press inward on the edges of the blank 31 while breaker bar mechanisms 135, 136 are actuated to contact the blank 31 with breaker bars 137, 138 and fold the blank 31 at the desired position and in the correct rib folding directions 143, 144. The breaker bars 137, 138 are mounted on levers 139, supported by rotary bearings 140 and are moved by pinned end pneumatic cylinders 141, 142. Once the fold is started in the blank 31 in the correct rib directions 143, 144, rib compression bars 146, 147 are moved inward to squeeze the two sides of the blank forming the rib 35 against the sides of the lower clamp body 110 to form the ribs 35. The rib compression mechanism 145 is driven by a pneumatic cylinder 149 with the motion supported by rotary bearings 148.

(26) A schematic diagram of the control and operation of a corrugated paperboard pallet assembly machine in FIG. 5 in accordance with the invention is shown in FIG. 9. The control 160 folds corrugated pallets 30 by taking in top blanks 31 into a pallet top former or folder 60 and forming the ribs 35. The control 160 also takes in bottom blanks 32 into a pallet bottom former or folder 62 and forms ribs 36. The pallet top 31 and pallet bottom 32 are then fed into the top and bottom joining section 75 where the top and bottom joiner 64 folds them together and produces a finished pallet 30. The pallet assembly machine is driven by air pressure from an air compressor 164 that provides pressure to solenoid valves 163 in the control section 161. The solenoid valves 163 are electrically actuated by a controller 162 which may comprise a computer or programmable logic controller. The controller 162 preferably controls the pallet assembly machine by time based open loop control wherein the solenoid valves for each motion are activated for set time periods longer than physically required by the respective motions. The motions move to mechanical stops 90 for reliably positioning and folding.

(27) The steps to fold the corrugated paperboard pallet are a function the pallet design. A step diagram of a machine process for use with a corrugated paperboard pallet production machine in FIG. 5 in accordance with the invention is shown in FIG. 10. The pallet assembly machine steps 170 comprise pallet top folding steps 171, pallet bottom folding steps 178 and top and bottom joining steps 185. The pallet top folding steps 171 include: Step 172picking up a blank 31 from the stack 71; Step 173supporting the blank 31 freely on supports 101, 102, 103; Step 174 registering or positioning the blank in position to be transferred into the rib folding station 60; Step 175stopping motion of the blank with edge stops 149; Step 176clamping the top blank 31 between top and bottom clamp sections 110 111; Step 177folding the vertically extending members or ribs 35.

(28) The pallet bottom folding steps 178 include: Step 179picking up a blank 32 from the stack 72; Step 180supporting the blank 32 freely on supports 101, 102, 103; Step 181 registering or positioning the blank 32 in position to be transferred into the rib folding station 62; Step 182stopping motion of the blank; Step 183clamping the bottom blank 132 between top and bottom clamp sections 110 111; and Step 184folding the vertical extending members or ribs 36.

(29) The pallet top and bottom joining steps 185 include: Step 186taking in the pallet top 31 and pallet bottom 32; Step 187registering or positioning the pallet top 31 and pallet bottom 32 in position to be clamped together with the notches 37 in the ribs 36 nested into the notches in the ribs 35; Step 188stopping motion of the pallet top and pallet bottom; Step 189clamping the pallet top and pallet bottom together upper and lower platens 84 and 85; Step 190folding the pallet top and bottom together; and Step 191ejecting the completed pallet to a palletizer, when utilized. The steps 170 are repeated upon a signal from the palletizer in step 192 that a pallet is needed.

(30) Obviously, numerous modifications and variations of the described preferred embodiment are possible and will occur to those skilled in the art in light of this disclosure of the invention.