Patent Application
20080223487
1. Technical Field
The present invention relates generally to methods for selecting random length materials such as wood flooring stock and bundling nested combinations of the stock into a standard length, and more particularly to an improved method for selecting, sorting and bundling plurality of random length stock into generally standard length combinations for compiling and bundling.
2. Description of the Prior Art
Solid wood flooring is typically produced in random lengths, which vary from nine inches to eight feet long. The length is determined by cuts made to remove randomly placed defects in the natural raw material.
The flooring stock is typically shipped in standard bundles ranging from seven to eight feet long, and therefore the flooring stock is conventionally bundled in one or two ways: (1) sorting by length to the nearest even foot in length, with various length bundles included on a single pallet; and (2) nesting various lengths of wood stock into a standard bundle, typically seven to eight feet long. In either case, the top layer of flooring in each bundle is inverted, so that the face of the product is protected from damage during shipping and handling.
Nesting is becoming the preferred method of bundling, because it is easier to handle and ship and typically assures a random assortment of lengths for the installer. The most popular method for assembling random length wood flooring into nested bundles uses people to manually assemble the bundles. Generally, a person will first determine the grade of the flooring board by visual inspection. The inspected stock is then placed into a rack and sorted by its approximate length. A person on the other side of the rack will then remove selected pieces from one or more slots in the rack, visually judging the lengths to make a row of the desired standard length, when the pieces are nested end to end. In this method, the wood stock is generally sorted into approximate one foot increments. However, rarely are the boards exactly cut to the foot, and therefore are either longer or shorter than the increment slot in the rack in which it is placed. For this reason, once a combination of pieces is selected by the person assembling the bundle, it is often necessary to remove and replace various pieces to adjust the overall length of the nested row to fit the predetermined standard.
On the other hand, if the person grading the stock sorts the stock into racks with smaller increments, the sorting rack must necessarily be larger, and more time must be spent determining the proper slot in the rack for storage, as well as determining appropriate lengths for selection and nesting into the desired predetermined length row. In some cases, a separate automated sorting mechanism is used to sort the wood stock by approximate length after grading. However, the nesting process is still currently accomplished manually by people. After enough rows of a proper length have been selected (usually twelve to fifteen rows for standard strip flooring) the top layer of product is manually inverted to protect the upper face of the product. The bundle is then tied together with plastic straps by a banding machine and the bundles are palletized for shipping.
As each row of nested lengths are assembled into a stack forming a bundle, each row is typically abutted flush, allowing the distal ends of the rows to vary. Thus, the bundle will typically include a proximal end with all rows abutted flush, and a distal end with a “jagged” appearance because of the various completed lengths of rows. In an alternative bundling method, each end of the pieces of material are abutted against stops, forming flush ends, with the gaps between nested pieces located in the middle of the bundle. Frequently, the interleaving of the pieces in this particular method is not adequate to hold the bundle together and the bundle is not as secure when bound. This method also makes it more difficult to estimate the total actual footage of the material in the bundle. Because the longest and shortest rows in the bundle are typically four to six inches longer or shorter than the predetermined average, longer pallets are necessary for shipping and storage.
In forming a “jagged end” bundle, the bundle assembler typically starts with a long piece of wood stock, or a combination of short pieces, and then chooses a short piece that will nest with the initial piece or pieces to approximate the desired predetermined length. This results in most of the short pieces being located at the jagged end of the bundle, which can then be easily dislodged from the bundle during handling and shipping. Frequently, when a truck or container of flooring is opened at its destination, dozens of short pieces of flooring have fallen from the bundles, with no way of determining which piece belongs to which bundle. This in turn results in a shortage of wood product from bundles, to the end user.
The process of assembling bundles is further complicated by the measuring rules commonly used in this industry. A standard machining or “end matching” allowance of ¾ inch is allowed on each piece of flooring. End matching is the process of putting a groove on one end of a piece of flooring stock and a tongue on the other end. The tongue and groove then interlock to prevent displacement of the ends of the flooring over time. The standard method of measurement for wood flooring calls for the addition of ¾ inch to the length of the face of each piece, in order to allow for the material which is necessarily removed by the end matching process. This means that, if a row is being assembled for a standard length bundle, it may be ¾ inch short if the row consists of one piece of wood stock, 1½ inches short if made up of two pieces of wood stock, etc. In practice, the average length is assumed, and the target bundle length is shortened by the required amount.
Industry grading rules also require a minimum average length for each grade. The system of the present invention allows the processor to easily keep track of this information. The current process of creating nested rows to form bundles by hand is time consuming, tedious, and proficiency requires consider experience. Some bundle assemblers never become good at choosing an acceptable combination of wood stock lengths on the first or second try, and therefore must spend additional time in a trial and error process to form a bundle. Further, the manual process of selecting rows for a bundle is not particularly accurate when assembled by hand, especially if the person assembling the bundle is in a hurry to create the bundle. Further, once assembled, it is difficult to obtain an accurate measure of the material which is included in each bundle, especially if the method of forming the bundle with two flush ends is utilized.
Several methods and devices have been proposed in the prior art, including Ahrens, U.S. Pat. Nos. 6,510,364 and 6,598,747. While the previous Ahrens patents do address many of these issues, the method used has some limitations. The measurement method is not particularly accurate, and may change as the feed wheels wear and is affected by feed wheel slippage. Also, the speed at which the Ahrens machine operates is not adequate to handle the production of a large flooring mill. It is designed to handle only one grade, and is not easily adapted to multiple grades. No provision is made for automation in loading the machine. Graders must still handle the boards in order to grade and load the machine. Finally and perhaps most importantly, however, the prior art method of Ahrens utilizes an entirely different sort method, specifically that it accumulated up to 16 individual boards in a storage rack and then determined the preferable solution consisting of one or more boards to form a row within the minimum and maximum tolerances. The number of possible combinations available in this scenario, however, is in the millions, and even after computing all of these combinations, the end result is only a single completed row, which greatly increases the inefficiency of the sorting process.
It is therefore a general object of the present invention to provide an improved bundling method for selecting random length pieces of product to form standard length bundles. This improved method is designed to analyze individual boards as they are fed into the sorting apparatus and determine on the fly where those boards should be sent to provide the best fit in each row to form a row having an overall length which falls within a predetermined length range for preparing bundles of product which are of generally similar length.
Another object is to provide a sorting and bundling method which is automated to improve the accuracy of the overall length of rows within a bundle and the average bundle size.
A further object of the present invention is to provide a sorting and bundling method which is capable of documenting the length of pieces within a bundle more accurately than possible when assembled by hand or by use of the disclosed prior art.
Still another object is to provide a sorting and bundling method which is capable of tracking minimum average length information for each grade of product. Also, the improved method gives the operator the option of maintaining an average length for a given grade of product by any of several methods. If the average length of the current production run is less than the desired target, the machine may reject short boards, downgrade short boards to a grade with lower average length requirements, or bundle short boards as a separate grade, allowing them to be sold as such, or blended back into production when the average length is more than required. The last is the preferred solution, since it allows full price to be realized for the short pieces and also improves consistency of product.
Finally, an object of the present invention is to provide an improved sorting and bundling method which is relatively simple and accurate in application is safe, efficient and effective in use.
The present invention provides a method for selecting and sorting a plurality of random length boards to form at least one row of boards having a total length within a predetermined target length range, the method comprising the steps of measuring the length of each of a plurality of random length boards and then feeding each of the plurality of random length boards into a programmable sorting device. The method then sorts each of the plurality of random length boards via the programmable sorting device into a plurality of accumulating rows to fill at least some of the plurality of accumulating rows with selected boards from the plurality of random length boards such that the selected boards in at least some of the plurality of accumulating rows form rows of boards having a total overall length within a predetermined target length range and each row of boards having a total overall length within a predetermined target length range is selected and transferred via a board row transfer device from at least one of the plurality of accumulating rows to a bundling device. Finally, the selected and transferred rows of boards are bundled via the bundling device by generally bunching, aligning and securing the rows of boards in a generally longitudinally aligned board row bundle.
The present invention as thus described provides substantial advantages over those board sorting and bundling methods found in the prior art. For example, because the present invention sorts the boards as they are processed through the apparatus in a generally continuous fashion, the efficiency of the process and the efficiency of operation of the apparatus is increased significantly over previous devices and methods. Furthermore, because the present invention and method automates the sorting and bundling process, users of the present invention will see large savings in labor and expense over those prior art devices and methods, which will significantly improve the user's bottom line. Finally, because the process and method of the present invention generally eliminates the need for manual manipulation of the boards in the sorting and bundling process, users of the present invention will see significant increases in safety and likely will see significant decreases in the amount of time lost to injury and disability caused by accidents occurring during the sorting and bundling process. It is therefore seen that the present invention provides a substantial improvement over those methods, systems and devices found in the prior art.
a and 9b are detailed side elevational views of the process by which a gate is opened to receive a board;
The selection and bundling apparatus 10 of the present invention is shown best in
Referring now to
The boards 200 are received as a plurality of random length boards which have been cut and processed earlier and are being delivered by conveyor belt 16 to the infeed section 20, and at this time or earlier in the cutting and finishing process, the grade of each board 200 must be determined. This may be accomplished by an automated grading scanner, a human grader inputting the grade with a switch or joystick or by a human placing each separate grade in a predetermined place such that the machine can determine its source, specifically by using different and multiple inflow conveyor belts each of which are associated with different grades of boards. Of course, the grading may also be entered directly into the central processor 180 which will keep an array of boards in its memory such that each board 200 passing through the present invention is uniquely tracked to ensure that differently graded boards are not included with the wrong grade. The boards 200 are then fed by a loading device or by hand into the board sorting and bundling device of the present invention, although the manual entry of the boards 200 is not currently recommended whereas the entry of the boards 200 by a preferred loading device is described herein.
Mounted at the rearward end 28 of inflow conveyor belt 24 at the rear end of the convergent guide rails 30a and 30b are board drop channels 36, as shown best in
As shown in
A series of longitudinally extended positioning rollers 46 are rotatably mounted adjacent and forward of the first section of floor 42 underneath the lugs 44. As the lugs 44 move the boards 200 held thereby forwards over the floor 42 of measurement section 40, the boards 200 contact the spinning positioning rollers 46 which drive each board 200 over to the inner side of the measurement section 40 against the inner guide wall 48 of the measurement section 40, as shown in
As shown best in
The board 200 is then transferred from the measurement section 40 to the sorting section 60 via a rotating transfer wheel 52. In the preferred embodiment, the rotating transfer wheel 52 rotates with an angular velocity which is generally identical to the speed of travel of the lugs 44, and would include a plurality of transversely extending board transfer bars 54 having generally L-shaped cross-sectional shapes which engage each of the boards 200 as they exit the measurement section and lift them out of the lugs 44 in which they were traveling, then carry them over to the sorting section 60 where each board 200 is dropped onto the floor 62 of the sorting section 60 for engagement by the pushing devices which move the boards 200 through the sorting section, as shown best in
In the preferred embodiment, each of the boards 200 would be engaged by an overhead lug 64 which is generally similar in design and construction to lugs 44 but is elevated above the floor 62, as shown best in
A series of transversely extending gates 76 are positioned in parallel configuration and pivotably mounted along the floor 62 of the sorting section 60 over which the board 200 is traveling, as shown in
The accumulator row section 80 in the preferred embodiment is shown best in
As the board enters the selected row 84 of the accumulating row section 80, the central processor 180 tracks the status of each accumulating row. Once the set of boards 200 within a particular row 84 reaches a total length which falls within the predetermined target length range, the central processor 180 dispatches a vacuum suction transport carriage 140 which is supported on rails 142a and 142b or tracks above the accumulating row section 80 and travels perpendicular to the positioning of the row of boards within the accumulating rows 84 so that the accumulating row 84 where the entire row of boards is to be picked up is easily accessed, picked up and supported by the carriage 140, as shown in
Since the preferred bundle size in most flooring mills is 3 rows wide by 4 or 5 layers high, the vacuum suction transport carriage 140 of the present invention is preferably designed to pick up and handle three (3) rows at one time. Thus, one trip of the carriage 140 will place one layer of product onto the bundle. Wider width flooring may be stacked 2 or 1 row wide, but rarely would a bundle have more than 3 rows in a layer. The accumulator rows 84 are spaced according to the widest width of flooring the machine is designed to handle. For example, 4″ wide flooring would normally require the accumulator rows 84 to be on 6″ centers, while 3.25″ flooring would require 5.25″ centers for the accumulator rows 84. However, of course, these distances may vary slightly with design details. Ideally, the rows need to be stacked on the bundles closer together to conserve conveyor space, allow for easier compaction of the columns of product, and also because the rows coming out of the flipper unit, as described later herein, are already close together. The vacuum suction transport carriage 140 therefore needs to be able to pick the rows up on 6″ or 5.25″ centers so that it is able to pick up 2 or 3 rows at a time if they happen to be next to each other. In fact, the computerized central processor 180 is programmed to give preference to complete rows which are being held in adjacent accumulator rows 84 to take advantage of this feature of the vacuum suction transport carriage 140. Of course, it should be noted that as the present invention will sort boards of only one width at a time, the row centers will not change once they are set by the computerized central processor 180 until the apparatus is cleared and begins sorting boards of a new width.
One, two or three rows are then picked up by the carriage 140 and the entire layer of two or three rows is then transferred by the carriage 140 to the bundling section 100, as shown in
The bundle 300 is then crammed together by opposing cramming plates 303a and 303b, as shown in
The important features of the present invention is that it is designed to take in a board 200 and determine which accumulating row 84 to deposit the board 200 in, without requiring prior buffering as is necessary with almost all other prior art methods and devices. In the present invention, the only available storage is in the plurality of accumulator rows 84. Typically between 16 and 24 rows need to be allocated for each grade, with only 6 or 8 rows needed to accumulate shorts. Rows are not predetermined to handle just one grade, but are dynamically allocated as needed by the sorting algorithm, taking into account the proximity of the bundle conveyors 306 designated to handle the particular grade of board 200. The difficult part of the process is to find a place for each board 200 while forming rows within tolerance and not running out of rows. It has been found, however, that the use of at least sixteen accumulating rows 84 for each grade will permit sorting and accumulating of over ninety to ninety-five percent (90% to 95%) of the boards 200 passing through the apparatus, and the use of more accumulating rows 84 will bring the number of unsorted boards 200 down even more.
To better understand the overall process of selecting, sorting, and bundling various lengths of boards, an overall view of the method, as shown best in
In one embodiment of the present invention, each board being carried on the device 10 is assigned to a grader based on the number of personnel available for grading. For example, if there were only a single grader available, he or she would grade each and every board passing through the device, whereas two graders would alternate grading every other board and three graders would each grade every third board, and so on and so forth. Once the board has been graded by the grading personnel, that information is stored in the appropriate register of the slat array and is available to the computer program which associates the particular grade with each and every selected board passing through the device.
The board then moves underneath the light curtain which determines the length of each piece of board and this information is coordinated by the computing device to enter into the board array so that the computer now associates each particular board with a length and grade in the board array. A shaft encoder and a slat sensor determines the starting point for the lugs and then the positioning and location of where the particular slats are located is known by the computer thereby determining the position of the board within the slat to see if it is at or near the first row of the appropriate grade sorting area as the board travels along the device. Once the board reaches the selected grade sorting area, the sorting algorithm is called by the computing system to determine the location into which the board should be placed.
The sorting algorithms, specifically the optimization subroutines, are shown best in
If the board is not a one-board solution, the finish row subroutine shown best in
The best row subroutine, after running, then returns to the optimization subroutine which inquires if a row was found for the board under scrutiny, and if one has been found, the optimization subroutine ends and then moves on to the next board to be sorted. If, however, a row was not found for that board, the empty row subroutine of
Once the designated row has been determined for a board, the board drops into the appropriate location and is gathered in the proper accumulator row. Once three full rows of a given grade are accumulated, the vacuum carriage previously described removes the rows from the accumulator and places them on the bundle conveyor or on the flipper device as was described previously.
If the bundle layer is to be the top layer of the bundle, it is pushed into the flipping device, rotated one hundred eighty degrees and pushed back out of the flipper in order to place the bottom of the boards in a “face up” position for transport purposes. The layer is then transported by the vacuum carriage to the bundle conveyor and the completed bundle is compacted horizontally by the cramming mechanism and resulting bundle is then sequenced through the banding device as was described previously. It is believed that this overall view of the “life of a board” should provide valuable assistance to persons wishing to understand operation of the method and apparatus of the invention, and application of the various detailed selecting, sorting and bundling aspects of the present invention to boards passing therethrough should be understood to be disclosed by the above disclosure and through reference to the drawings accompanying this document.
It is to be understood that numerous additions, modifications and substitutions may be made to the improved board sorting and bundling apparatus and method 10 of the present invention which fall within the intended broad scope of the appended claims. For example, the size, shape, and construction materials used in connection with the present invention may be modified or changed so long as the intended functional characteristics of the present invention are generally maintained. Also, although the infeed section 20, measurement section 40, sorting section 60, accumulating row section 80, bundling sections 100, vacuum suction transport carriage 140 and central processor 180 have been described as including certain particular functional elements and features, modification of these elements and features which do not significantly degrade or destroy the functionality of the various sections should be understood to fall within the intended broad scope of the appended claims. Furthermore, modifications to the specific application of the method elements of the present invention should be understood to be a part of this disclosure so long as the general sorting algorithms used in the present invention are not significantly degraded or destroyed. Finally, although the present invention has been described for use in connection with the sorting and bundling of wood floor boards, it should be noted, of course, that it may be used for any purpose for which the apparatus and method are suited, and it is expected that the present invention may be used for sorting of other wood board types in the same efficient and safe manner.
There has therefore been shown and described an improved board sorting and bundling apparatus and method 10 which accomplishes at least all of its intended objectives.
