Patent Publication Number: US-2006011266-A1

Title: Variable dimension engineered timber system

Description:
FIELD  
      The present invention relates to a method and apparatus for making timber systems, posts, beams or headers of variable dimensions with a minimum of cutting waste and utilizing conventional standard wood processing equipment.  
     BACKGROUND  
      Composite posts, beams and headers are posts, beams and headers made up of elongated component pieces of lumber either specially milled to have a desired cross-sectional shape or having a rectangular square edge shape. Pieces with a square edge shape are generally selected from standard lumber such as 2×4s, 2×6s, 2×8° s., etc. If posts, beams or headers having dimensions between those possible with standard lumber are required, using such lumber can result in a large amount of waste and make the process commercially unacceptable.  
      If the elongated wood pieces to make a post, beam or header are available, it is then necessary to glue the pieces of lumber together to form a post, beam or header usually of square or rectangular cross section. Placing one wood piece over another constitutes a lamination process, which results in a maximum of wood fiber in a given cross-sectional area and hence a maximum cost per unit area of post, beam or header cross-section. Making a box-like structure with spaced apart sides, top and bottom results in a square or rectangular hole in the center and is a less costly structure but more difficult to fabricate than a laminated post, beam or header. Such structures require a press to compress the glue joints while they are setting and a strong guide to prevent the pieces from moving sideways during compression. Other prior art such as U.S. Pat. No. 5,870,876 issued to Deiter and U.S. Pat. No. 6,519,912 issued to Eckmann et al. require a sophisticated and costly two-dimensional press exerting pressure vertically as well as horizontally.  
      Using conventional large dimensional lumber for such hollow core construction creates a problem in that such lumber is dimensionally less stable and tends to warp and split easily, thereby reducing the structural integrity of the fabricated post, beam or header.  
      It is an object of the present invention to provide a method of minimizing lumber cutting waste and maximizing lumber recovery in making cost effective composite hollow core posts, beams or headers of any dimension, which are dimensionally stable, don&#39;t warp or split and are structurally sound. It is a further object of the invention to provide a method which can form the posts, beams or headers with a single conventional one-dimensional press.  
     SUMMARY OF THE INVENTION  
      According to the invention there is provided a method for fabricating posts, beams, headers, and boards from elongated lumber pieces. The method includes providing a plank made of elongated, edge-glued lumber pieces and cutting the plank into elongated boards of precise, predetermined dimensions to produce stock for subsequent fabrication. The boards that are to be stock are cut so as to minimize cutting and trimming waste in subsequent operations.  
      Preferably, the method includes preparing the elongated boards for gluing, applying glue to each of the gluing surfaces and assembling the boards into a post, beam or header and compressing the gluing surfaces using a one-dimensional press.  
      The providing step may include planing the elongated lumber pieces followed by edge gluing and trimming.  
      The preparing step may include notching each board so as to mate with a notch on an adjacent board when the edges of the each board and the adjacent board are in a predetermined orientation.  
      The providing step may alternately include finger-jointing prior to planing and edge gluing of the elongated lumber pieces.  
      Preferably, the compressing step is applied perpendicularly to each of the gluing surfaces.  
      The providing step may, alternately, include finger-jointing the elongated lumber pieces, profiling edges of the elongated lumber pieces and edge gluing the profiled elongated lumber pieces.  
      The notches are, preferably, V-shaped.  
      By utilizing edge glued lumber, lumber widths of large dimensions can be achieved. Compared to solid large dimensional lumber, such edge glued lumber is much more consistent and dimensionally stable and less likely to warp and split. By cutting this material to precise widths selected to allow for planing, trimming and notching, waste fibre is minimized as is the cost of the post, beam or header. Lateral movement of the lumber pieces during gluing is avoided by providing notches and notch projections, which fit into the notches with the notch projections being parallel to the direction of force applied by the press.  
      The gluing process allows the operation of a conventional one-dimensional press which is proven technology requiring less capital and a lower level of complexity, thereby reducing the overall manufacturing cost of the products. At the same time it permits the fabrication of sophisticated glue-up patterns all in one gluing step including compression and tension members such as high rated machine stress rated (MSR) lumber or laminated veneer lumber (LVL) which can be added for higher strength.  
      There are numerous benefits which can be achieved by this invention some of which are as follows: 
      1. Ability to utilize low cost raw material 
        Trim blocks, which can be bought at very low cost, are sorted and processed into square edge and waney sorts in order to maximize lumber recovery. This fiber sort is the lowest cost material as saw millers typically process this lumber into chips for paper production.     Low grade lumber, which has been down-graded because of wane, an attribute not desired in traditional lumber, may be used. This lumber can be processed through a chop line to sort out the square edge and waney blocks in order to maximize fiber recovery.     Pre-graded short block lumber can go directly into the process.    
        2. Ability to achieve highest recovery from purchased lumber 
        Lower strength lumber can go into products such as glulam (or fascia) where a higher volume of lumber is utilized allowing the product to still meet the customer strength expectations.     Higher strength lumber can go into the Variable Dimension Engineered timber where less lumber is utilized, effectively reducing the cost of the product.     Square edge lumber can either be sold into traditional markets or it can be edge glued using traditional means and used in Variable Dimension Engineered timber products.     Waney lumber can be edge glued using the technology described in my co-pending patent application Ser. Nos. ______. ______ and ______, thereby providing the highest recovery from purchased lumber.    
        3. Ability to construct a product with the least amount of solid lumber necessary to meet required strength requirements 
        Overall a 10 to 45% fiber utilization benefit can be expected with the present invention depending on the size of post, beam or header being manufactured. This is significant given the fact that fiber is the most important cost factor.     A benefit of a product made in accordance with this invention is that it is lighter to work with, allowing it to be easily handled on the job site without the use of cranes and other lifting equipment.    
        4. Ability to manufacture with high flexibility and at high production rates in order to keep costs down. 
        There is no need to re-edge much of the waney blocks because they can be processed directly into the finger jointing and edge gluing process.     The same finger jointer and edge glue lines can be used to process both the waney edge and square edge lumber keeping capital costs lower and improving operating efficiencies.     Because a conventional one-dimensional press can be utilized, capital costs and complexity of the press line is lower. This process may also require less press equipment compared to the double-sided press option.     The conventional press permits the addition of stabilizing members in the middle of larger products or additional tension and compression members in order to ensure performance and quality at reasonable cost.     The volume of adhesive consumed is lower than with other engineered wood products as there are less glue lines in the products. Given the high cost of adhesives, this helps to keep costs low.     The use of edge gluing keeps inventories to a minimum, as there is no concern with the size of the inbound lumber for any specific order. This will allow faster response to customer needs and a reduction of inventories, work in progress and costs.    
        5. Ability to manufacture a product of high quality and performance which the market demands 
        This invention results in an engineered product which will not warp, twist, crack, check or shrink, even in larger dimensions.     The tighter grading specifications for smaller dimensional blocks compared to that for solid lumber in larger dimensions results in a higher overall grade of finished product.     This invention produces a product that will not swell when exposed to rain and moisture as is common with some other engineered wood products.     The present product is a lower cost alternative compared to traditional engineered wood products.     The present product can be available in long lengths to allow customers to chop it for builder specific requirements.     A product is achieved by this invention which meets precise traditional finished dimensions. Such dimensions are exemplified by the following: 
            typically widths of 3.5 and 5.5 inches, and     depths of 5.5, 7.25, 9.25, 11.25, 11.875, 14, and 16 inches.    
           
       

    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Further features and advantages will be apparent from the following detailed description, given by way of example, of a preferred embodiment taken in conjunction with the accompanying drawings, wherein:  
       FIG. 1  is a cross-sectional view of a post made up of four different elongated pieces of lumber, two of which are different from the other two;  
       FIG. 2  is cross-sectional view of a portion of two beams/headers showing different shaped interlocking notches;  
       FIG. 3  is a cross-sectional view of a portion of two beams/headers showing a double V-shaped notch and a square-shaped notch;  
       FIG. 4  is a rectangular beam/header having a center stabilizer;  
       FIG. 5  is a large dimension square post having a center stabilizer;  
       FIG. 6  is a beam/header configuration with non edge-glued Lumber or LVL as compression or tension members;  
       FIG. 7  is a beam/header having additional compression and tension members;  
       FIG. 8  is a cross-sectional view of a laminated beam/header made by a conventional glue laminating process—the difference to standard glulam, however, is that this beam uses edge glued material and can be of non-standard with;  
       FIG. 9  is a cross-sectional view of a three-sided beam (corbel) which encloses a 2×4 rafter; and  
       FIG. 10  is a cross sectional view of two elongated lumber pieces glued together in the form of a corner resulting from a large square post cut into four pieces. 
    
    
     DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS  
      Referring to  FIG. 1 , a post  10  of square cross-section is formed of two lateral elongated lumber pieces  12  and  13  and two vertical elongated lumber pieces  18  and  20 . In this embodiment, pieces  12  and  18  are formed using interlocking edged glued boards while pieces  13  and  20  have employed a square edge glued board. V-shaped notches  15  are milled into pieces  12  and  13  and corresponding V-shaped protrusions  14  on pieces  18  and  20 . The notches  15  and protrusions  14  positioned so that upon alignment as shown, the protrusions  14  fit into the notches  15  and hold the pieces  12 ,  13 ,  18 , and  20  in position. The lumber pieces  12 ,  13 ,  18 , and  20  can be cut to the exact required dimensions thereby minimizing trim and planer waste. Alignment of the interlocking notches  15  and projections  14  along a single direction allows the use of a single press to glue the beam pieces together.  
      Referring to  FIGS. 2 and 3  there are shown various interlocking configurations. In  FIG. 2  there is shown a single V-shaped notch  27  formed in piece  22  and a projection  26  formed in piece  24 . There is also shown a projection  30  in piece  32  having parallel sides with a rounded top and a corresponding notch  31  in piece  28 . In  FIG. 3  there is shown a pair of V-shaped projections  38  and  40  in piece  36  and V-shaped notches  39  and  41  in piece  34  forming interlocking elements. Also shown in  FIG. 3  is a projection  42  with a rectangular cross-section in piece  46  and a corresponding notch  43  with rectangular cross-section forming an interlocking configuration.  FIGS. 2 and 3  are embodiments of typical interlocking configurations; other configurations are also possible.  
      Referring to  FIG. 4  there is shown a compound configuration of elongated lumber pieces forming a rectangular beam/header  50  with a center stabilizer piece  52  for added strength and stability.  FIG. 5  shows an alternative post  64  of square cross-section with a center stabilizer  66  extending from the interior of a top of the beam  64  to the interior of a bottom of the beam  64 .  FIG. 6  is a beam/header configuration  60  with non edge-glued Lumber or LVL  62  as compression or tension members and  FIG. 7  is a rectangular beam/header with sides  56  and  58  and  53  and  54  has additional compression member  60  and tension member  62  laminated on top and bottom, respectively.  
      Alternative structures can be built such as the conventional glulam beam/header  68  in  FIG. 8 , the U-shaped beam  69  (corbel) which engages a rafter tail  70  seen in  FIG. 9  and the L-shaped corner structure  71  shown in  FIG. 10 .  
      As seen in  FIG. 11 , the process of fabricating the various composite posts, beams or headers consists of using conventional lumber, measuring its moisture content and grading it in the chop line. Wet lumber is kiln/air dried when required. In addition or alternatively, pre-graded lumber, such as finger-joint blocks, or trim ends can be used.  
      The standard system is able to handle both square-edged lumber and waney lumber. Waney lumber is lumber cut from near the outside of the log with one or both corners rounded off and irregular.  
      At steps  86  and  90 , the lumber pieces are finger jointed to other such pieces to achieve the requisite length. Short trim ends are finger jointed at step  82  in the short block finger jointing line. If the lumber is square edged it is planed at step  88  and then edge-glued and trimmed at step  94 . Step  94  can be omitted if the input lumber has already the desired dimension.  
      For waney lumber, a special profiling at the corners is milled at step  92  in order to make the lumber useable to make planks. After profiling at step  92 , the lumber is edge-glued and trimmed at step  94 .  FIGS. 12 and 13  show, as an example, a waney 2×6 having sloped edges  104  as shown in dotted outline being profiled at step  92  to form finger-like faces  107 . By reversing alternate profiled 2×6s  103 , applying glue to the finger-like faces and pressing them together, at step  94  one gets a plank  108  with lateral dimensions as wide as desired.  
      The resultant structure after step  94  is a plank made of edge-glued profiled or square-edged lumber. With edge-glued lumber it is possible to cut the plank to the exact width required for a given post, beam or header, leaving as little waste as possible; the only exception being if the input lumber has already the desired dimension, then trimming in step  94  would be bypassed.  
      Depending on market situation and customer demand there are a number of possible processing options for the boards made up of edge-glued profiled or square-edged lumber or the finger jointed input lumber: 
          a) Variable Dimension Engineered Timber;     b) Laminated Beams of variable dimensions in cross-section in steps  104 ; or     c) Rafter or conventional lumber in steps  106 .        

      For the Variable Dimension Engineered timber, the boards are planed and notched at step  96 . At step  98 , the lumber is then laid-up and glued together to form a post, beam or header using a conventional one-dimensional press. With the notches as shown in  FIG. 1  pointing along a direction parallel to a common axis, the fitted lumber pieces become self-aligning, and when compressed do not tend to drift laterally as could otherwise be the case. When the glue is dried, the post, beam or header is then finished at step  100  and packaged and shipped at step  102 .  
      The steps  104  describe fabrication of a conventional laminated beam, but one which can be of any desired dimensions.  
      It is obvious that various interlocking, profiled shapes are possible. It is also obvious that one can bypass the finger jointing step if lumber of sufficient length and quality is available. It is also obvious that the final product in the process of  FIG. 11  up to step  94  could be conventional boards or lumber of any desired width cut from edge-glued planks  108 .  
      Accordingly, while this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to this description. It is therefore contemplated that the appended claims will cover any such modifications or embodiments as fall within the true scope of the invention.