Abstract:
A method for densifying a fibrous mat, such as scrim, to achieve a uniform mat density, comprising a set of parallel bars each having a row of pins extending downward therefrom which can engage the mat fibers, a plurality of shafts along which the bars slide so as to maintain the bars parallel, a plurality of extendable accordion linkages connecting the set of bars, and a linear positioning assembly having a reciprocating drive mechanism coupled to one of the bars which can move the bars in response to an actuation signal. As the drive mechanism retracts the bar to which it is coupled the spacing between the rows of bars is decreased uniformly and the rows of pins draw the fibers together and compress them uniformly across the width of the mat.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a divisional of co-pending U.S. patent application Ser. No. 13/023,082, filed Feb. 8, 2011, the disclosure of which is incorporated herein by reference in its entirety. 
     
    
     FIELD 
       [0002]    The present disclosure generally relates to apparatus used in forming engineered wood products. More particularly, the present disclosure relates to an apparatus for compressing a fibrous mat to achieve a uniform density. 
       BACKGROUND 
       [0003]    Processing the trees into engineered products involves a number of steps. One of the steps is crushing young trees (stripped of branches) to obtain loose bundles of fibrous strands. The bundles of fibers are formed into mats of crushed fibers with the fibers being generally parallel. Resin is added as well as other binding agents and the mat is dried under pressure to eventually reach a target moisture content and density. After the fibers are formed into mats and before resin is added the mats must be processed to provide a uniform density of fibers across the width W (i.e., perpendicular to the direction of the fibers, see  FIG. 1 ) of the mat. 
         [0004]    It is important for the mat to have a uniform density of fibers across the entire mat width W so that the resulting wood product has uniform and predictable strength. Density variation can cause failure of the wood product in use, which can have disastrous effects where the wood product is load bearing. 
         [0005]    Old growth unprocessed wood generally has been more desirable for making engineered wood products than new growth unprocessed wood or pulpwood, in part because of the lower moisture content of older trees. Pulpwood is commonly defined as wood that is about 12-60 years of age or of a certain diameter (to be distinguished from veneer or dimension lumber). Old growth trees are rapidly vanishing as forests are depleted. New “immature” tree farms are increasing in development to provide a nearly limitless source of such wood. Such farms can grow trees at a faster rate using modern technology. Immature trees can be harvested at a younger age than old grow trees, however, there is a greater variation of fiber density in immature trees than in old growth trees, resulting in a need for improved methods of producing uniform density mats. 
         [0006]    One type of conventional apparatus which attempts to create a uniform density mat of fibers utilizes a pair of parallel vertical opposing plates between which is inserted a mat coming off, for example, a scrim line, to be compressed (also referred to as “densified”). One or both plates are connected to a reciprocating drive mechanism which drives the plates toward each other, compressing the fibrous mat therebetween. A challenge with this apparatus is that the compressive force is applied to the front and rear edges ( 4 ,  6  in  FIG. 1 ) of the mat proximate to the plates, but the compressive force is not evenly applied across the width of the mat. The result can be that the mat has a higher density near the front and rear edges and lower density in the middle of the mat. Additionally, a nonuniform density mat may tend to decompress over time. If the density is not consistent, the moisture content of the mat after drying is not consistent, which affects the rest of the manufacturing process and the performance characteristics of the final wood product. Delamination can result if the moisture content is too high; insufficient bonding can result if the moisture content is too low. In a veneer production process, if the mat thickness varies, the veneer thickness can vary. In a sawmill operation, the result of inconsistent density can be inconsistent wood dimensions. 
         [0007]    It would be desirable to have an apparatus which could densify a fibrous mat uniformly across the mat and improve the resulting strength characteristics. It would also be desirable to use density to control moisture content. 
       SUMMARY 
       [0008]    In one exemplary embodiment of the present disclosure an apparatus is provided for uniformly densifying a fibrous mat. A densifying assembly includes a set of parallel bars each having a row of pins extending downward therefrom which can engage the mat fibers, a plurality of shafts along which the bars slide so as to maintain the bars parallel, a plurality of extendable accordion linkages connecting the set of bars, and a linear positioning assembly having a reciprocating drive mechanism coupled to one of the bars which can move the bars in response to an actuation signal. As the drive mechanism retracts the bar to which it is coupled the spacing between the rows of bars is decreased uniformly and the rows of pins draw the fibers together and compress them uniformly across the width of the mat. 
         [0009]    In another exemplary embodiment an apparatus is provided including a carriage frame having front and rear rails, left and right side rails, a plurality of downwardly extending brackets, each bracket having a roller mounted thereon by a bearing. The apparatus further includes a densifier assembly comprising a plurality of generally parallel elongated bars comprising a plurality of passive bars disposed between a drive bar and a static bar, the static bar being connected to the carriage frame, a plurality of pins associated with and extending downward from the drive bar and each of the passive bars; a plurality of extendable and retractable accordion linkages arranged generally parallel to each other and generally perpendicular to the bars, each accordion linkage being associated with at least one point on each bar, the accordion linkages being adapted to maintain each row of elongated bars in a generally parallel relationship to each other and permitting the distance between the bars to expand or contract proportionately so that the spacing between the rows of bars is equal while the overall spacing between adjacent bars increases or decreases, and a plurality of shafts slidingly associated with the passive bars and the drive bar and fixedly associated at one end with the static bar; at least one linear positioning assembly having a reciprocating drive member having a first and a second end, the first end being attached to the carriage frame, a coupler for coupling the second end of the reciprocating drive member to the drive bar, and, a motor operatively associated with the reciprocating drive member; a vertical positioning assembly including at least one support plate connected to the frame, and at least one reciprocating drive mechanism connected to the at least one support plate for raising and lowering the bars; a main frame having at least four legs, a pair of front and rear members, a pair of opposing side members, the densifier assembly and carriage frame being slidingly positioned and the rollers resting on the pair of side members, a conveyor, and a reciprocating drive mechanism connected to the main frame and to the carriage assembly; a weight detector for weighing the mat to obtain weight data; a surface area sensor for detecting the surface and edges of the mat to obtain square footage data; and, a processor in communication with the weight detector and the surface area sensor for calculating a densification value based on the weight and square footage data indicating the distance the drive bar must travel in order to provide a desired densification. The drive bar is reciprocatingly slidable in response to actuation by the linear positioning assembly motor and drive shaft. The rows of pins are insertable in the mat and when the drive bar is urged toward the static bar the passive bars move so as to decrease the distance between rows of bars and cause the pins which are inserted into a mat to compress the mat in a direction across the face of the mats and generally uniformly along the length of the mat. 
         [0010]    In another embodiment of the present disclosure, the apparatus described hereinabove further includes a stripper assembly for removing fibrous material which may adhere to the pins after removal of the pins from the mat when the densification has been achieved. The stripper subassembly assembly includes a frame; a plurality of stripper members associated with the frame; a plurality of gaps defined in the stripper members, a pin being insertable into and removable from a gap; a positioning mechanism for raising and lowering the frame and stripper members with respect to the pins such that the stripper members are proximate to the pins and strip the pins of fibers or other material when the pins pass through the gaps. 
         [0011]    In another embodiment of the present disclosure, an apparatus is provided for densifying a mat having fibers aligned in a generally parallel direction and having a front edge and a rear edge parallel to the direction of the fibers whereby the distance between the front and rear edges defines the width of the mat, the apparatus including means for providing a uniform compressive force to the mat, the compressive force being applied at a plurality of points throughout the mat and substantially the entire width of the mat so as apply substantially the same compressive force to substantially all the fibers at the same time so as to achieve a substantially uniformly densified mat. 
         [0012]    Another embodiment of the present disclosure provides a method for increasing the density of a fibrous mats, the mat having a grain defined as the direction of the face of the mat, comprising (a) weighing a mat to obtain weight data; (b) scanning the mat with a detection device to obtain square footage data; (c) determining from the weight and square footage data a densification value indicating how much the mat is to be compressed; (d) actuating an apparatus for increasing the density of the mat, the apparatus being as described hereinabove; and, (e) moving the rows of pins so as to compress the mat substantially uniformly across the grain of the mat. The method may also include a step (f) moving the compressed mat of step e) away from the linear positioning apparatus and toward a location for stacking a plurality of compressed mats. The method may also include a step (g) resetting the rows of pins to accommodate another mat. The method may also include a step (h) assembling a plurality of sets of compressed mats and cutting the sets of mats to a desired length. 
         [0013]    Another embodiment of the present disclosure provides a mat formed by the method disclosed herein. The mat has a substantially uniform density. The mat also has substantially uniform moisture content. 
         [0014]    A feature of the apparatus of the present disclosure is that by controlling densification of the mat during processing, the moisture content can be controlled. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The invention is illustrated in the drawings in which like reference characters designate the same or similar parts throughout the figures of which: 
           [0016]      FIG. 1  is a schematic top plan view of an undensified mat. 
           [0017]      FIG. 2  is a schematic top plan view of a densified mat. 
           [0018]      FIG. 3  is a side elevational schematic view of a first exemplary embodiment of an apparatus according to the present disclosure and showing the main subassemblies. 
           [0019]      FIG. 4  is a top plan view of the apparatus of  FIG. 3 . 
           [0020]      FIG. 5  is a top plan view of one embodiment of the carriage frame assembly. 
           [0021]      FIG. 6  is a north elevational view of a densifier assembly. 
           [0022]      FIG. 7  is a top plan view of a portion of the densifier subassembly showing the frame and linear positioning actuator. 
           [0023]      FIG. 8  is a top plan view of a portion of the densifier subassembly showing the accordion linkage and linear positioning assembly. 
           [0024]      FIG. 9  is a side elevational view of a stop assembly for the densifying subassembly. 
           [0025]      FIG. 10  is a side view of the densifying subassembly highlighting the linear positioner, with the accordion linkage extended. 
           [0026]      FIG. 11  is a side view of the densifying subassembly highlighting the linear positioner, with the accordion linkage retracted. 
           [0027]      FIG. 12  is a top plan view of a stripper assembly. 
           [0028]      FIG. 13  is a side view of the stripper assembly. 
           [0029]      FIG. 14  is a side detail view of a portion of the stripper and densifying subassemblies. 
           [0030]      FIG. 15  is a flow diagram of one exemplary method for densifying a fibrous mat. 
       
    
    
     DETAILED DESCRIPTION 
     Overall Apparatus 
       [0031]    Steam press scrim lumber (“SPSL”) is composed of processed mats of fibers obtained by crushing and processing logs of generally small diameters. A conventional mat  1  (see  FIGS. 1 and 2 ) is made of fibers  2  and is several inches thick. The mat  1  has a front edge  4 , a rear edge  6 , width W and length L. An uncompressed mat  1  which is still being processed may have different areas in the mat having areas of relatively low fiber density  7  and regions of relatively higher fiber density  8 . This is common for many unfinished mats. See, for example, the process described in co-pending U.S. patent application Ser. No. 12/579,332 entitled “Method for Drying Wood Product and Product Obtained Thereby” commonly assigned to the assignee of the present disclosure (and which is incorporated by reference herein in its entirety). Often individual mats  1  are gathered together to form a set of mats for further processing. The densifier apparatus and method of the present disclosure increases the density of a formed mat to achieve a uniform desired density.  FIG. 2  shows a densified mat  9  made according to the present disclosure in which the fibers have been compressed evenly from the front edge  4  to the back edge  6  so as to provide a generally uniform density across the densified mat  9 . For the purposes of the present disclosure, the term “across” means across the width W and between the front edge  4  to the back edge  6 , or at least a portion of that distance. The terms “densified” and “compressed” are equivalent and mean an increased density of the fibers in the mat. 
         [0032]    The main assemblies include a main frame, carriage frame assembly, and densifier assembly. The densifier assembly includes a densifying subassembly and a stripper subassembly. 
         [0033]      FIG. 3  shows one exemplary embodiment of an apparatus  10  having a main frame  100 , densifier assembly  20  and carriage frame assembly  21 . 
         [0034]    Main Frame 
         [0035]      FIGS. 3-4  show one exemplary embodiment of an apparatus  10  and the basic structure of a main frame  100 . The main frame has legs  101 , front and back rails  102 ,  104 , and opposing side rails  106 ,  108 , each side rail may have a track  110  preferably inset in the top surface (as described further hereinbelow). The carriage frame assembly  21  rests on top of the main frame side rails  106 ,  108 . The carriage frame  21  (including densifier assembly  20 ) is rolled in a reciprocating manner in the tracks  110  by at least one, and preferably a pair of carriage drive mechanisms  112 , each of which includes a drive piston  114  connected at one end to a main frame side rail (e.g., rail  106 ) and at the other end to the carriage side frame member (e.g., frame member  82 ). Each piston  114  is connected to a drive motor  116 . The main frame  100  also includes a back stop  118  an exit conveyor assembly  120 , which may be, for example, a belt  122  associated with a pair (or more) of rollers  124  and a motor  125 . 
         [0036]    It is to be understood that in the present disclosure reference to air cylinders, pistons, actuators or other linear motion-inducing devices is intended to include other drive mechanisms, such as, but not limited to, pneumatic, hydraulic, belt, ball screw, chain drive, and the like. Such devices are also intended to include (if not specifically mentioned) associated valves, actuators, motors, PLC communication connections and the like normally associated with such devices for ordinary functioning. It is also to be understood that reference to a particular number of such devices is intended to include at least that number and the scope of the present disclosure include additional (or possibly fewer) units, unless otherwise specifically excluded. 
         [0037]    The main frame  100  is divided into two main areas, a densification area  126  and a mat gathering area  127  (see  FIG. 4 ). Mats  1  are introduced into the densifier assembly  20  at the densification area  126  by an introduction conveyor  128  (not shown) having an infeed belt  129  or by other conveyance means situated proximate to or abutting the main frame. Mats densified by the densifier assembly  20  are moved offline by the exit conveyor  120  toward the back stop for further processing. 
         [0038]    Carriage Frame Assembly 
         [0039]      FIG. 5  shows a carriage assembly having a carriage frame  21  having front and rear frame members  82 ,  84  and side frame members  86 ,  88 . Extending downward from each end of the side frame members  86 ,  88  are rollers  90  (each with an associated bearing  92 , not shown) attached to a roller mount  94 . It is to be understood that two or more rollers  90  may be spaced along the side frame members  82 ,  84  between the ends. The carriage frame  21  rests on top of and transversely (and reciprocatingly) rolls in the main frame side rail tracks  110  by means of a motor driven gear drive  114  mounted on the main frame  100  and associated with synchronous belts  116  attached to each side of the carriage frame  21 . A belt take up  117  is located at either side of the carriage frame  21 . 
         [0040]    The carriage frame assembly  21  has mounted to it a pair of vertical raising and lowering actuators  95  and associated mechanism for raising and lowering the densifier assembly  20  in response to an electronic signal from the processor  140  (discussed in more detail hereinbelow). The carriage frame assembly  21  has also mounted to it a pair of actuators  66  and associated air valves for raising and lowering a stripper assembly  21 . Thus, the densifier assembly  20  is raised and lowered with respect to the carriage frame assembly  21  so that a mat  1  can be positioned under the densifier assembly  20 . The stripper subassembly  60  The carriage frame assembly can move horizontally on the main frame  100 . 
         [0041]    Densifier Assembly 
         [0042]    The densifier assembly  20  consists generally of a densifying subassembly  19  and a linear stripper subassembly  60 . 
         [0043]    Densifying Subassembly 
         [0044]      FIGS. 6-9  show a densifying subassembly  11  including a frame  12  comprised of front and rear rails  13 A,  13 B and opposing side rails  13 C,  13 D. The frame  12  also includes four or more vertically mounted shafts  14  and bearings, which are also mounted to the carriage frame assembly  21 . The frame  12  can be raised or lowered with respect to the carriage frame assembly  21  by two or more vertical raising and lowering actuators  95  mounted on the carriage frame assembly  21 . 
         [0045]    The densifying subassembly  11  also includes a number of elongated passive densifying bars  22  (see  FIG. 8 ) each have at least one and preferably several openings and associated bearing  24  at each end and preferably and an associated opening and bearing near the midpoint of each bar  22 . The passive bars  22  are spaced apart and maintained in a generally parallel configuration by several shafts  26  which pass through the bearings  24  and openings and which are horizontally mounted to the front and rear rails  13 A,  13 B of the densifying subassembly  11 . At each end of the shaft  26  is an end cap collar  32 . The shafts  26  provide guidance and support for the passive bars  22 . A static end bar  28  is positioned at the rear end of the densifying subassembly  11  and attached to a drive bar  30  which is movably positioned proximate to the front rail  13 A. The bars  22  can be solid, or may be hollow tubing, C-shaped, L-shaped, U-shaped or other shaped elongated bent plates, and are preferably made of metal, plastic, alloy, combinations thereof or the like or other durable, generally rigid material. The drive bar  30  and the passive bars  22  can move reciprocatingly along a portion of the length of the shafts  26 . The drive bar  30  and each passive bar  22  have a plurality of spaced apart downwardly extending pins  40 . 
         [0046]    The densifying subassembly  20  has at least one, and, in one exemplary embodiment, a plurality of extensible accordion linkages (also known as extensible scissors linkages)  42  spaced across the bars  22 ,  28 ,  30 . In one embodiment the accordion linkages  42  are mounted on top of the bars  22 ,  28 ,  30 . Each accordion linkage  42  is attached via at least one pin  44  to each bar  22 ,  28 ,  30 . The accordion linkages  42  function to maintain the bars  22 ,  28 ,  30  in a generally equal spaced relationship; in other words, as the passive and drive bars  22 ,  30  are moved along the shafts  26  the accordion linkages  42  maintain the same relative distance between each bar  22 ,  30 . 
         [0047]    The densifying subassembly  11  includes at least one (two are shown in the drawings) stop assemblies  15  (see  FIG. 9 ), which include stop blocks  16  which are mounted to the carriage frame assembly  21 . A pair of guide shafts  17  and bearings are mounted to each stop block  16  on either side of the vertically mounted actuator  95  which raises and lowers the densifying subassembly  11 . 
         [0048]    The passive and drive bars  22 ,  30  are moved along the shafts  26  by means of a linear positioning actuator  50  (see  FIGS. 10-11 ). The linear positioning actuator  50  has a drive mechanism, such as, but not limited to, a ball-feed screw  52  and a drive motor  53 . Alternatively, instead of a ball-feed screw  52  a piston can be used. The actuator  50  is connected at one end by a coupling  54  (such as, but not limited to, a clevis (shown in the drawing), eye hook or the like) to the drive bar  30  and at the other end to the rear rail  84  of the carriage frame assembly. The actuator moves the drive bar  30  and passive bars along the shafts  26  toward or away from the stop assemblies  15 . The accordion linkages  42  maintain the passive bars  22  in a generally equal relative spacing (labeled as Sp in  FIG. 8 ). It is to be understood that more than one linear positioning actuator can be included along the length of the densifying subassembly  11 . If desired, the densifying subassembly  11  can be operated as a standalone apparatus separate from the conveyor apparatus. 
         [0049]    Stripper Subassembly 
         [0050]    The apparatus  10  may also include a stripper assembly  60  (see  FIGS. 9 ,  12 - 13 ) to strip or scrape fibers and resin from the pins  40  after they have been removed from a densified mat  9 . The stripper subassembly  11  includes a frame having a pair of side frame members  61 A,  61 B. Also included are a number of stripper surfaces  62  comprising elongated bent L-shaped plates  63  (see  FIG. 9 ) which are mounted on the side frame members  61 A,  61 B. The plates  63  may be mounted so that pairs of adjacent plates  63  have the vertical part of the L shape back-to-back and the horizontal part of the L shape are opposing in two adjacent pairs of plates  63 . The pins  40  pass through the gaps  64  between adjacent plates  63 . 
         [0051]    In an alternative embodiment, rather than being L-shaped plates, the strippers may be generally flat elongated plates which have holes or openings in which the pins  40  may be inserted or removed. The holes are sized to be close in diameter to the diameter of the pins  40  so that when the pins are removed from the densified mat the pins  40  pass through the holes and the edge of the hole scrapes extraneous matter (e.g., fibers and resin) from the pins  40 . Alternatively, other configurations of stripper devices can be used, such as doctor blades, spring mounted flexible pieces of materials (e.g., metal), brushes, scrapers or the like. 
         [0052]    The stripper subassembly  60  can be vertically raised and lowered and guided by vertically mounted shafts  65  and bearings which are attached to the top of the carriage frame assembly rails  86 ,  88  and driven by a pair of actuators  66  mounted on the carriage frame assembly  21 . 
         [0053]    As shown in  FIG. 14 , a stop bar  67  is a stop that is lowered when a mat  1  is entering the densifier assembly  20  on the infeed belt  129  and raised to discharge a compressed mat  9 . Stop rub rails  68  are guides used for guiding the stop bar  67  up and down. 
         [0054]    During the densification process mat fibers may stick to the pins  40 . The stripper subassembly helps to remove mat fibers from the pins  40  when the pins  40  are removed from a densified mat  9 . When the pins  40  are withdrawn from a mat they pass through the stripper surfaces  62 , which scrape off the fibers from the pins  40 . The densifying subassembly  11  and stripper subassembly  60  can be raised and lowered independently of each other. The stripper subassembly  60  is mounted on the carriage frame assembly  21  and the densifying subassembly  11  is mounted above the stripper subassembly  60  on the carriage frame assembly  21 . 
         [0055]    The relative movement of the assemblies and subassemblies with respect to the main frame  100  is described as follows. The carriage frame assembly  21  itself can move horizontally on the main frame  100 . The densifier assembly  20  can be raised and lowered with respect to the carriage frame assembly  21  so that a mat  1  can be positioned under the densifier assembly  20 . The stripper subassembly  60  can be raised and lowered independently of the densifying subassembly  11  so that the pins  40  can be stripped of extraneous material. 
         [0056]    Measuring Sensors and Logic Control 
         [0057]    An infeed conveyor assembly  128  (see  FIG. 4 ) includes a conveyor  128 A and an infeed belt  129 . A weight sensor  130  is positioned under the infeed belt  129  to the densifier assembly  20  and weighs each mat  1  as it enters the densifier assembly  20 . A surface area detector  132 , such as a camera, CCD device, or the like, is positioned above the infeed belt and is used to calculate the surface area of each mat  1  at the same time it is being weighed. 
         [0058]    A programmable logic controller (“PLC”)  140  (not shown) is in electronic communication with the linear positioning drive motor  58 , densifier assembly vertical positioning cylinders  95 , the linear positioning assembly drive motor(s)  58 , the stripper subassembly actuators  66 , the carriage drive motors  116 , and/or various other components. The PLC  140  is also in communication with the weight sensor  130  and the surface area detector  132 . Preferably, the PLC  140  includes a user interface control panel  142  (not shown) for programming and operating the PLC  140 . 
         [0059]    Exemplary Method 
         [0060]    One exemplary method of densifying a mat  1  using the apparatus  10  of the present disclosure is now described, with reference to the flow diagram shown in  FIG. 15 . Each densifying operation starts with an uncompressed mat  1  and produces a compressed mat  9  which can be positioned next to other compressed mats which are further processed. The overall process may be considered a continuous batch process. 
         [0061]    The mat  1  is introduced by the infeed belt  129  and is weighed by the weight sensor  130  and scanned (for surface area) by the surface area detector  132 . From this information the PLC  140  calculates the amount of densification needed to achieve the desired mat density. The PLC  140  determines the distance the linear positioning screw  54  must travel and the distance the drive bar  30  must travel to compress the mat  1 . 
         [0062]    The mat  1  is fed to the densification area  127  underneath the densifier assembly  20  by the introduction conveyor  128 . The mat  1  is oriented on end with the fibers  2  being in a direction generally parallel to the bars  22 . The mat  1  may have variable fiber density across the mat prior to densification, such as lower fiber density areas  7  and higher fiber density areas  8 . The densifier assembly  20  is initially configured so that the distance between the drive bar  30  and the static bar  28  is roughly the width W of the mat  1 . The densifier assembly  20  is raised and lowered by the vertical actuators  95  so that the pins  40  are pushed into or removed from the fibers  2 . 
         [0063]    The linear positioning actuator  54  is actuated by the PLC  140  and the drive bar  30  is drawn toward the stop block. The passive bars  22  move simultaneously, with the accordion linkages  42  maintaining the same relative spacing “Sp” between the bars  22  as the distance between the bars decreases. The pins  40  push and compress the individual fibers (or bundles of fibers) together uniformly. 
         [0064]    One feature of the presently described apparatus and method is that the result of having all the pins  40  on all the passive bars  22  and drive bar  30  moving the same proportionate distance at the same time is that substantially the entire mat  1  (from the front edge  4  to the rear edge  6 ) is compressed by the same amount. Thus, the density of the densified mat  90  is now essentially uniform across the width W of the mat. This is in contrast to prior densification apparatus, which typically sandwich the mat between two external plates which drive the front edge toward the rear edge. 
         [0065]    After the mat  1  (now identified as densified mat  9 ) is compressed to the desired width, the carriage frame assembly  21 , with densifier assembly  20  (and a mat  9  with the pins  40  still inserted therein), rolls on the main frame side rails  106 ,  108  in response to actuation of the main frame side rail pistons  114  and away from the densification area  127  and onto the exit conveyor  120 . The stripper subassembly  60  is raised just prior to raising the pins  40 . The densifier assembly  20  is raised by the actuators  95  and the pins  40  are removed from the mat fibers  2 . The carriage frame assembly  21  is moved horizontally back to the densification area  126  for processing of the next mat  1 . The densified mat  9  is conveyed toward the back stop  118  which has a gathering area  127  at the end of the conveyor  120 . Densified mats  9  are crowded together and accumulated in this gathering area  127 . These sets of mats  9  can be further processed, such as cut and stacked. The process is repeated with the next mat  1  being fed into the densification area  126 . 
         [0066]    The following describes one nonlimiting example of the method described above using an example of measurements and calculations to illustrate the densification determination. The surface area detector  132  scans the surface area of the mat  1 . The square footage determines the “starting” width of the mat  1 . The PLC  140  actuates the linear positioning actuator  50  and sets the initial spread of the pins  40  so that all the rows of pins  40  are in the fibers  2 . The PLC  140  is programmed and preset for a given mat width or density. 
         [0067]    A 30 inch wide by 9 foot long mat (22.5 sq ft) may weigh about 65 lbs. The PLC  140  calculates the starting density from these numbers as being 3.0 lb/sq. ft. A desired end density, e.g., 3.4 lb/sq. ft, is programmed into the PLC  140 . Accordingly, the surface area needs to be compressed from 22.5 sq. ft down to 19.1 sq. ft to achieve this density. The width W needs to be compressed 4.5 inches, i.e., from 30 inches wide to 25.5 inches wide. The PLC  140  actuates the linear positioning actuator  50  to move the drive bar 4.5 inches. The accordion linkage  42  retracts and pins  40  drive and compress the fibers  2  substantially evenly across the mat  1  to achieve the desired width and thus the desired density. It is to be understood that compression, while occurring substantially evenly, may still result in areas of small density variation across the width of the mat. 
         [0068]    A feature of the presently described densification method and apparatus is that the densified mat  9  stays densified after the pin force is released. If the mat had been compressed only by squeezing the front and rear mat edges  4 ,  6  toward each other, the mat  9  would tend to decompress because it was not compressed uniformly. 
         [0069]    The densified mat  9  formed by the apparatus and method of the present disclosure has a more uniform density and moisture content across the width W of the mat than has been achievable by other known techniques. The density of the mat to be formed by the apparatus and method described herein can be selected by the apparatus operator. The density variation can be 
         [0070]    The apparatus and method of the present disclosure can be adapted for use with materials other than crushed wood mats and the densifier assembly can be used to increase the density of any of a variety of materials which can accommodate the pins  40 . The densifier assembly  20  can be adapted to have the pins  40  be marking “fingers” and used to create a set of rows of marks across a mat or sheet of material. Alternatively, rather than pins, lasers, cutters or drill bits can be substituted so that a set of uniform and controllable width rows of holes can be created in a sheet of material, such as steel, by having the hole-creating devices lowered onto the sheet of material from above. The apparatus  10  can be adapted for creating a uniform density of large foam or cotton particles in creating mattresses or other articles requiring a uniform density of material and where the pins  40  can be inserted into and removed from the material to be densified. 
         [0071]    Although only a few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims. 
         [0072]    Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that an order be inferred, in any respect. 
         [0073]    As used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. 
         [0074]    “Optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not. 
         [0075]    The headings of various sections are used for convenience only and are not intended to limit the scope of the present disclosure. 
         [0076]    Throughout the description and claims of this specification, the word “comprise” and variations of the word, such as “comprising” and “comprises,” means “including but not limited to,” and is not intended to exclude, for example, other additives, components, integers or steps. “Exemplary” means “an example of” and is not intended to convey an indication of a preferred or ideal embodiment. “Such as” is not used in a restrictive sense, but for explanatory purposes. 
         [0077]    Disclosed are components that can be used to perform the disclosed methods, equipment and systems. These and other components are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc., of these components are disclosed that while specific reference of each various individual and collective combinations and permutation of these may not be explicitly disclosed, each is specifically contemplated and described herein, for all methods, equipment and systems. This applies to all aspects of this application including, but not limited to, steps in disclosed methods. Thus, if there are a variety of additional steps that can be performed it is understood that each of these additional steps can be performed with any specific embodiment or combination of embodiments of the disclosed methods. 
         [0078]    It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the scope or spirit. Other embodiments will be apparent to those skilled in the art from consideration of the specification and practice disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit being indicated by the following inventive concepts. 
         [0079]    It should further be noted that any patents, applications and publications referred to herein are incorporated by reference in their entirety.