Abstract:
The present invention relates to a flexible sheet of wood strips for use in the fabrication of engineered floor boards or wood sheets and including the machine and method of manufacture of the flexible sheet of wood strips. The wood strips provide a wood floor which has much more stability than a solid wood plank which is much more affected by the temperature in a room and the moisture under the floor board. Also solid wood planks are much more expensive than engineered wood planks where only a very thin layer of quality wood material is utilized. The transverse wood strips are constructed of inferior wood material. Two or more treads of flexible material may be secured transversely to the wood strips to provide additional retention of the wood strips in the flexible sheet.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates generally to a flexible sheet of wood strips for use in the fabrication of engineered floor boards or wood sheets and including the machine and method of manufacture of the flexible sheet of wood strips. 
       BACKGROUND OF THE ART 
       [0002]    It is known to construct engineered floor boards which comprise a top layer of a quality wood material and a bottom or core layer formed of transverse wood strips. Such a board is described, for example, in U.S. Pat. Nos. 5,736,227, 5,935,668 and U.S. Pat. No. 7,152,379. These wood strips are secured by glue to the top wood layer and extend transverse to the longitudinal axis of the top wood layer to provide longitudinal flexibility and dimensional stability to the board. US Publication No. 2004/0226243 discloses a two-ply flooring plank which has two layers of plies, with a bottom layer having a grain that runs generally transverse to the top layer to provide dimensional stability to the plank. The bottom layer is comprised by a number of strips secured to the bottom of the top layer and the strips are placed with gaps therebetween to allow flexibility of the flooring plank, which allows a flooring formed by such planks to more easily conform to irregularities in a sub-floor upon which the flooring plank is mounted. 
         [0003]    It is common to fabricate the wood strips in a machine wherein the wood strips are held together by wires which are squeezed into slots which have been cut in a common surface of the wood strips when assembled together. Instead of using wires held in friction fit in slots, it is also known to secure the wood strips in side-by-side relationship by use of adhesive tapes or adhesive fiber layers. The wood strips may also be spaced-apart. However, with these methods, wood strips often become detached during manipulation and transportation. Also, because these wood strips are made from inferior wood products, some of the strips are susceptible to warping, particularly, when left in storage for lengthy time periods. This warping also causes additional problems in that the spacing between the boards becomes irregular. These problems result in additional costs in the fabrication of wood boards glued on such strips. The result is that the irregular spacing causes larger gaps between adjacent wood strips or no gap and this translates in a telegraphy of the wider gaps on the surface of the top layer which is very thin. It is desirable to have constant width grooves to provide longitudinal flexion and prevent telegraphy. 
       SUMMARY OF THE INVENTION 
       [0004]    It is therefore a feature of the present invention to provide a flexible sheet of wood strips which substantially overcomes the above-mentioned disadvantages of the prior art. 
         [0005]    Another feature of the present invention is to provide a machine for the fabrication of flexible sheets of wood strips for use in the fabrication of engineered floor boards. 
         [0006]    Another feature of the present invention is to provide a method for the fabrication of flexible sheets of wood strips for use in the fabrication of engineered floor boards and which overcomes the disadvantage of the prior art. 
         [0007]    According to the above features, from a broad aspect, the present invention provides a flexible sheet of wood strips. The wood strips are held together in side-by-side aligned spaced relationship by thermofusable glue droplets spaced-apart at predetermined locations along opposed side edges of the wood strips to interconnect the wood strips to one another between the opposed side edges and provide a flexible joint of substantially constant width between these opposed side edges. 
         [0008]    According to another broad aspect of the present invention, there is provided a machine for the fabrication of flexible sheets of wood strips. The machine comprises feed means for supplying a plurality of wood strips to a transporter. The transporter has equidistantly spaced-apart wood strip engagement means for transporting and orienting the wood strips in spaced sequence adjacent a glue droplets applicator wherein two or more glue droplets are disposed at spaced-apart predetermined locations along a longitudinal side edge of each of the wood strips. Wood strip transfer means is provided for transferring the wood strips with the glue droplets to an input end of a conveyor where the wood strips are disposed side-by-side and interconnected in spaced relationship along opposed side edges thereof by the glue droplets. The conveyor has displacement means for engaging and conveying the wood strips interconnected in spaced relationship from opposed top and bottom surfaces and to squash any of the glue droplets projecting above the top and bottom surfaces of the wood strips interconnected by the glue droplets. Pressure means is associated with the conveyor to apply pressure across the wood strips from opposed top and bottom surfaces thereof to keep the wood strips flat. The glue droplets are dried and/or cooled sufficiently along the conveyor for the glue droplets to provide a mechanical retention force to retain the wood strips in interconnected spaced-apart relationship to form the flexible sheets of wood strips. 
         [0009]    According to a still further broad aspect of the present invention, there is provided a method for the fabrication of flexible sheets of wood strips for use in the fabrication of engineered floor boards. The method comprises the steps of providing a plurality of elongated wood strips having similar dimensions. The wood strips are fed in a predetermined orientation to a transporter. The longitudinal side edge of the wood strips are oriented to receive two or more spaced-apart glue droplets from a glue droplets applicator which applies two or more spaced-apart glue droplets along the longitudinal side edge. The wood strips are then transferred with the glue droplets thereon to an input end of a conveyor where the wood strips are disposed side-by-side and interconnected in spaced relationship along opposed side edges thereof by the glue droplets. The wood strips are conveyed interconnected in spaced relationship from opposed top and bottom surfaces thereof. Pressure is applied across the wood strips to stabilize the wood strip and to squash any of the glue droplets projecting above the top and bottom surfaces of the wood strips. The conveyor is of sufficient length for the glue droplets to dry or cooling sufficiently to provide a mechanical retention force of the glue droplets to retain the wood strips in interconnected spaced-apart relationship to form sheets of the wood strips. 
         [0010]    According to still further broad aspect of the present invention, there is provided a flexible engineered wood sheet comprising a top wood sheet fabricated from a quality wood material glued to a surface of a sheet of wood strips. The wood strips are held together in side-by-side aligned spaced relationship by thermofusable glue droplets spaced-apart at predetermined locations along opposed side edges of the wood strips to interconnect the wood strips to one another between the opposed side edges and also providing a flexible joint of substantially constant width between the opposed side edges. The wood strips have a longitudinal axis thereof disposed transverse to a grain orientation axis of the top wood sheet to provide flexibility of the top wood sheet along the grain orientation axis and dimensional stability to the flexible engineered wood sheet. 
         [0011]    Further details of these and other aspects of the present invention will be apparent from the detailed description and figures included below. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0012]    Reference is now made to the accompanying figures depicting aspects of the present invention, in which: 
           [0013]      FIG. 1  is a fragmented top view of a flexible sheet of wood strips for use in the fabrication of engineered floor board and constructed in accordance with the present invention; 
           [0014]      FIG. 2  is a transverse section view showing an end section of the flexible sheet of wood strips and wherein the end strip is wider than the adjacent wood strips; 
           [0015]      FIG. 3  is an enlarged cross-section view, partly fragmented, illustrating the position and utility of the interconnecting glue droplets; 
           [0016]      FIG. 4  is a fragmented section view illustrating an embodiment of how floor boards can be fabricated using the flexible sheet of wood strips of the present invention; 
           [0017]      FIG. 5  is a perspective view of the machine for the fabrication of flexible sheets of wood strips in accordance with the present invention; 
           [0018]      FIG. 6  is a perspective view similar to  FIG. 5  but viewed from the opposed end of the machine; 
           [0019]      FIG. 7  is a fragmented perspective view showing the front end portion of the machine; 
           [0020]      FIG. 8  is a perspective and fragmented side view showing the loading end of the machine and the transfer of the wider wood strips to the transporter for the delivery of the wood strips to the thermofusable glue droplets application station; 
           [0021]      FIG. 9  is a fragmented perspective view showing the application of thermofusable glue droplets on the side edge of the boards and their transfer into the assembly and press section of the conveyor; 
           [0022]      FIG. 10  is an enlarged perspective view showing the thermofusable glue droplets application station; 
           [0023]      FIG. 11  is a further enlarged perspective view showing the transfer of the wood strips with their glue droplets into the assembly end of the press conveyor; and 
           [0024]      FIG. 12  is an enlarged perspective view showing the press conveyor. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0025]    Referring to the drawings and more particularly to  FIGS. 1 to 3  there is shown generally at  10  a flexible sheet of wood strips constructed in accordance with the present invention. The flexible sheet of wood strips comprises a plurality of wood strips  11  generally formed of resinous wood material which are held together in side-by-side aligned spaced relationship by thermofusable glue droplets  12  disposed spaced-apart at predetermined locations along opposed side edges  13  and  13 ′ of adjacent wood strips  11  and  11 ′. The thermofusable glue droplets  12  interconnect the wood strips  11  to one another between the opposed side edges  13  and  13 ′. The droplets are of substantially identical volumes to provide a constant spacing between the strips. 
         [0026]    As herein shown, retention means in the form of elongated treads  14  of flexible material are secured to a face  15  of the wood strips  11 . Alternatively, a tread of flexible material may be connected to each of the wood strips by suitable means such as staples to provide interconnection of the wood strips to prevent their detachment from the glue droplets. As shown in  FIG. 1 , there are two of the treads  14  of flexible material disposed spaced-apart and these provide additional retention of the wood strips for the handling thereof such as when staking them in bundles and transporting them and manipulation at the assembly plant where floor boards are manufactured. The flexible treads  14  are formed of polyester fibers or other fibers impregnated in glue coatings disposed across the outer face  15  of the wood strips  11 . As shown in  FIG. 4 , the polyester fiber treads  14  are positioned on the flexible sheet of wood strips at a location whereby to lie between the thin top quality wood sheets  20 . A glue is applied on the top outer surface  15  of the wood strips  11  prior to the positioning of the thin quality wood sheets. The wood strips  11  are elongated rectangular wood strips and define opposed flat top and bottom surfaces and transverse straight flat side edges  13 . The glue droplets  12  as well as the flexible treads  14  maintain these wood strips spaced-apart with substantially constant spacing therebetween as determined by the glue droplets. The glue droplets also provide flexibility to the sheet  10  of wood strips. Although the wood strips are herein shown of constant dimension, the sheet of wood strips may comprise wider wood strips at specific intervals whereby during the fabrication of engineered floor boards the wider wood strips would be positioned at the ends of the wood boards to provide sufficient material to rout grooves to provide an interconnection of the wood boards together in the fabrication of a wood floor. 
         [0027]    With reference to  FIG. 4 , there is shown a manner in which floor boards can be fabricated using the flexible sheet of wood strips  10 . The flexible sheet  10  of wood strips  11  is disposed flat on a support surface, such as a conveyor and thin sheets  20  of quality wood material are disposed thereover with the wood strips  11  extending transversely to the long axis and grain orientation of the sheets  20 . As herein shown the connecting polyester fiber treads  14  secured to the flexible sheet of wood strips lie between the top quality wood sheets  20  and are therefore not present behind the sheets  20 . A glue is applied on the top outer surface  15  of the wood strips  11  prior to the positioning of the thin quality wood sheets  20 . 
         [0028]    Referring now to  FIGS. 5 to 12 , there will be described the machine for the fabrication of the flexible sheets  10  of wood strips. The machine is generally identified by reference numeral  25  and comprises an inlet board strip feeding mechanism  26  to position and load a supply of wood strips one by one to a transporter mechanism  39 . As shown in  FIG. 7 , the inlet feeding mechanism  26  is comprised of a feed conveyor  26 ′ on which the strips are loaded. The feed conveyor  26 ′ has aligning means to supply wood strips in aligned position to the transporter mechanism  39 . This aligning means is comprised by a stationary side fence  60  secured on a loading side of the feed conveyor and a pivoting and reciprocating pusher fence  61  located on an opposed side for pushing wood strips placed on the feed end of the feed conveyer  26 ′ with an end thereof abutting against the stationary side fence  60  wherein the wood strips are disposed in side-by-side parallel relationship on the feed conveyor  26 ′. 
         [0029]    Referring to  FIGS. 7 and 9  there is illustrated the construction of the transporter mechanism  39 . As herein shown, it is comprises of a pair of spaced-apart transport circular discs  39 ′ secured to a common driven shaft or axle  40 . The transport circular discs  39 ′ have transversely aligned wood strip transport slots  41  radially disposed in equidistantly space relationship about the outer edge  41 ′ of the circular discs and oriented outwardly. A controller  9  (see  FIG. 6 ) controls the operation of an intermittent drive of the driven axle  40  and the operation of all moving parts of the machine. 
         [0030]    Referring again to  FIG. 9 , it can be seen that the circular disc  39 ′ supports the wood strips with a the longitudinal side edge  13  thereof oriented outwardly. The drive motor of the axle  40  is synchronized to stop every time the wood strips reach its vertical position as identified by the wood strip bearing reference numeral  11 ″′ positioned under the glue droplet applicators  29 . As herein shown, there are four glue droplet applicators  29  to apply four spaced-apart glue droplets  12  on the top side edge  13  of the wood strips. These applicators are provided with dispensing nozzle  29 ′ as better illustrated in  FIG. 10 . After the glue droplets are applied the transport circular discs  39  are caused to rotate to position the next wood strip, held by the transport circular discs  39 , in position under the applicators  29 . Meanwhile, the previous wood strip with the glue droplet is displaced towards a transfer mechanism  30  which consists of a pair of transfer discs  31  also secured on a driven shaft or axle  43  which is drivingly coupled to the driven axle  40  of the transport circular discs  39 ′. 
         [0031]    The transfer discs  31  are disposed in spaced relationship with the transport circular discs  39 ′ whereby transfer teeth  44  formed in the outer periphery of the transfer wheels progressively engaged the wood strip having the glue droplets disposed thereon and transfers it from the transport circular discs to a feed mechanism  45  which transfers the wood strip to an input end  31 ′ of a conveyor  32  where said wood strips are accumulated in predetermined quantity and disposed with their longitudinal side edges to be in contact with one another and interconnected by the glue droplets. Accordingly, the wood strips interconnect by their glue droplets at the input end of the conveyors  32 . 
         [0032]    Referring to  FIG. 11 , there is shown the construction of the feed mechanism  45 . The feed mechanism comprises a support frame  45 ′ on which are secured two pairs of feed arms  48  and  48 ′ which are mounted on respective linear guide tracks  49  and  49 ′ and are displaced in a reciprocating motion with respect to one another. As herein shown, the feed arms  48 ′ are wider than the feed arms  48  which are displaced inside the outer feed arms. Each feed arm is equipped with a pusher finger  46  and  46 ′ to engage a wood strip from the transfer wheels  30  to discharge the wood strips from the wheels and push them over a straight guide support  50 ′ and onto a feed chain  46 ″ disposed at opposed ends of the input end  31 ′ of the conveyor. These feed arms are operated at high speed to ensure the proper discharge of the wood strips  11  from the transfer discs  31 . A motor  47 , operated by the controller  9 , drives timing belts  47 ′ to operate the feed arms in reciprocating motion to ensure controlled spacing. Accordingly, the wood strips  11  stack-up to a predetermined quantity at the input end  31 ′ of the conveyor  52  and the glue droplets interconnect the opposed side edges of the accumulated wood strips together. 
         [0033]    Referring to  FIGS. 6 ,  7  and  12  there is shown the construction of the conveyor  32 . The conveyor has a support platform  50  to which is secured a bottom belt conveyor  51  displaceable over a vertically oriented flat support plate  50 ″. A top belt conveyor  52  is displaceable above the bottom belt conveyor to form a transport gap  53  therebetween. Two or more pressure plates, herein a plurality of pressure plate  34  are disposed transversely behind the top belt conveyor to apply pressure to a top side of the wood strips interconnected in spaced relationship and conveyed by the bottom and top belt conveyors along the transport gap  53  over the support plate  50 ′ to prevent deformation of the wood strips. 
         [0034]    The bottom and top belt conveyors  51  and  52  are comprised of two or more belt conveyors, herein four, constructed of a flexible glue release material such as silicon, whereby not to adhere to the glue droplets. The belt conveyors are aligned with the glue droplets to squeeze any glue droplets exceeding the top and bottom surface of the wood strips. The top and bottom belt conveyors are vertically and longitudinally aligned with one another and transversely spaced for alignment with the glue droplets which interconnect the wood strips. They are driven in synchronism. 
         [0035]    The pressure plates  54  are adjustable pressure plates whereby to set a desired pressure on the wood strips within the transport gap  53  and to adjust for the thickness of the wood strips. Also the conveyors are of a sufficient length to permit the glue droplets to cool down to the point that they apply sufficient mechanical resistance to maintain the wood strips interconnected to one another along their opposed side edges and maintain a substantially constant spacing between the wood strips. 
         [0036]    The conveyor belts are herein shown trained about driving idle rolls with the idle roll assembly  56  and  56 ′ being adjustable to apply tension on the belt conveyors to provide sufficiently tension and traction force to maintain the strips in position along the transport gap  53 . 
         [0037]    As can be better seen in  FIG. 6 , the exit end  36  of the machine is provided with devices to apply a further means of retention of the wood strips interconnected by glue droplets. This means of retention can be, for example, the application of a tread or band of flexible polyester fibers impregnated with glue and applied on the top surface of the assemble wood strips exiting the conveyor. As herein shown, the machine is equipped with two glue tape applicators  35  which applies the retention strips  14 , as illustrated in  FIG. 1 . 
         [0038]    As previously described in the fabrication of engineered wood boards, it is common that the wood boards be provided with a wider wood strip at opposed end of the wood board whereby interconnecting joint can be formed therein, such as a lap joint or tongue and groove joint. The machine  25  of the present invention provides for this wider board at the inlet feeding mechanism  26  which is equipped with a magazine  27  whereby to store wood strips of wider dimension. These wood strips are disposed in the machine at specific locations whereby to lie at the ends of the quality wood sheets disposed thereon whereby to effect a connecting joint. The insertion of these wider wood strips is programmed in the computer of the controller  9 . As shown in  FIG. 8 , the wider wood strips, herein wood strips  8  are discharged from the bottom end of the magazine  27  by a pivoting positioner  70  which transfers the wood strips  8 , in a guided fashion, at the bottom of the magazine  27  and into a vacant one of the transport slots  41  of the transport disc  39 ′. In order to have a vacant slot  41  at that location the feed conveyor  38  has a pressure plate  37  which is actuable to retain the wood strips at the feed end of the feed conveyer immediately in front of the transport circular disc  39 ′. Two of these wider wood strips are fed in sequence to define an end of a strip of flexible wood strips completed and the beginning of a next strip. The controller will stop the operation of the wood strip feeding assembly whereby to create a space between the already completed wood strips sheet and the next one to be formed if it is desired to have a space therebetween. Otherwise, the sequence will continue with the sheets abutting one another. 
         [0039]    Briefly, the method for the fabrication of the sheet of wood strips of the present invention will now be described. The method generally comprises providing a plurality of elongated wood strips  11  having similar dimensions. These wood strips are fed in a predetermined orientation to a transporter mechanism  28 . The wood strips are oriented with a longitudinal side edge thereof to receive deposits of two or more spaced-apart glue droplets thereon under a glue droplets applicator which may be provided with two or more dispensing nozzles whereby to apply two or more spaced-apart glue droplets along the longitudinal side edge of the wood strips. The method further comprises transferring the wood strips with the glue droplets to an input end of a conveyor where the wood strips are disposed side-by-side and interconnect in space relationship along opposed side edges thereof by the glue droplets. 
         [0040]    The method further comprises conveying the wood strips interconnected in spaced relationship from opposed top and bottom surfaces thereof. Pressure is applied across the wood strips to prevent warping and displacement of the wood strips and to press any of the glue droplets projecting above the bottom surfaces of the wood strips. The conveyors are of sufficient length whereby to permit the glue droplets to dry along the conveyor to provide sufficient retention force of the glue droplets to retain the wood strips interconnected in spaced-apart relationship to form a flexible sheet of wood strips. As shown in  FIG. 3 , the glue droplets provide for the flexion between adjacent wood strips. 
         [0041]    It is pointed out that the step of providing a plurality of elongated wood strips comprises storing a plurality of wood strips, and manually positioning the wood strips on the feed conveyor  38 . The step of orienting the longitudinal side edge of the wood strips to receive the glue droplets as herein shown is comprised by a transporter which receives wood strips in slots and orients the wood strips to a vertical position under glue applicators to receive glue droplets and then transfers the wood strips to the transfer wheels  30 . The transfer wheels are disposed in spaced relationship to one another on a drive axle and driven in synchronism with the circular disc  39  of the transporter whereby to transfer the wood strips to a feed mechanism which transfers the wood strips to the input end  31 ′ of the conveyor  32  where they are continuously assembled. The conveyor engages the top and bottom surfaces of the wood strips by the belt conveyors whereby the wood strips are conveyed in a transport gap and under the pressure plates where pressure is applied to prevent the wood strips from deforming. Also a loading magazine is provided to store wider wood strips which are inserted in the assembly at predetermined locations to form the outer ends of the sheet of wood strips to receive routed interconnection grooves. 
         [0042]    It is within the ambit of the present invention to cover any obvious modifications of the preferred embodiments described herein provided such modifications fall within the scope of the appended claims. It is also contemplated that the flexible sheet of wood strips  10  may be used for the fabrication of flexible engineered wood sheets which would be comprised of a thin top wood sheet fabricated from a quality wood material glued to a surface of the sheet of wood strips. The wood strips extend transverse to the grain direction of the top wood sheet. This would provide a sheet which has longitudinal flexibility or flexibility in the grain direction with the wood strips also providing for dimensional stability of the flexible engineered wood strips.