Abstract:
Material-recovery apparatus for obtaining usable, uniformly-dimensioned blanks from scrap. Apparatus is small, and economical in manufacture and operation, using only a single lifting jack and vertical support unit to support the tool-and-feed-roller housing. Feed-roller tensioning units for exerting downward force on rollers have a spring-biased bell-crank mechanism.

Description:
BACKGROUND INFORMATION 
     1. Field of the Invention 
     The invention relates to the field of material-recovery operations. More particularly, the invention relates to the recovery of valuable, usable material from under-utilized and waste-stream material. More particularly yet, the invention relates to the use of material-removing tools in the recovery of usable material from under-utilized and waste-stream material of various shapes and sizes. 
     2. Description of the Prior Art 
     Inherent in a manufacturing process is that one or more products are produced according to specifications that define the shape and size of the product, that is, that each exemplar of the product produced by a particular process ideally has a shape and size according to the applicable specification. A particular problem in a manufacturing process in which an exemplar of a product is cut or otherwise produced by a material-removing process is that the material that is left over may have a shape or size that renders it useless for obtaining any more exemplars of the particular product according to specification, though it may contain sufficient material to provide one or more different products. In spite of such collateral use, such left-over material is normally deemed to be scrap and channeled into a waste-material stream in which the material is converted into a low-value chip or mulch by-product, discarded as waste into a landfill, or perhaps burned for fuel. 
     A sawmill is a typical example of a manufacturing operation that generates left-over material that may be useful material for other operations. The mill takes round logs, often with the bark still attached, and converts them into square and rectangular products. In the sawing process, material forming the outside perimeter of each log ends up as irregularly shaped slabs, edgings, and waney material of random thickness and/or width. The term “waney” as used hereinafter refers to stock or material that has waning, i.e., diminishing, dimensions, such as presented by a tapered piece of wood. Such waney material, however, often contains enough wood from which to obtain one or more pieces of a high-value product, such as uniformly dimensioned stock or blanks for turning or component stock. Although this material is potentially valuable, the sawmill owner is not interested in working with it, as the sawmill is not equipped for processing small pieces of short and/or irregularly shaped wood. 
     Wood is used in this discussion to illustrate the generation of material that is “scrap” for one particular type of manufacturing operation and a high-value material for another operation. It should be understood, however, that any material-removing process used to create a product will also produce a “scrap” material that may be remaindered, i.e., declared a left-over, material that is valuable and usable for manufacturing other high-value products. Hereinafter, “scrap” material that is usable to create other products will be referred to as “remaindered material”. It should also be understood that, although wood is the material most commonly referenced herein as “the material”, other substances exist that can be used in a material-removing process to form articles or products. These include plastic materials, hard rubber, etc., are therefore also included in the definition of remaindered material in the following discussion of material-recovery operations. 
     Until now, it has been quite costly to process remaindered material because of the fact that the traditional approach requires several types of machines and several labor-intensive operations to process irregularly shaped pieces of material coming in a range of thicknesses, widths, and lengths, so as to render it useful. As a result, such remaindered material often flows into a waste-material stream or is chipped and burned as fuel. This is not only wasteful in terms of responsible use of natural resources, but cost-ineffective for several reasons. 
     The wood that is left over after the sawing or other material-removing processes is generally very expensive wood when valued on a cost-per-unit-weight or cost-per-unit-volume basis. Not only is the wood contained in this remaindered material generally jacket wood, i.e., the outer layer of wood on a tree, and the highest quality wood in the tree, it has also passed through one or more processing operations and has been handled extensively. It is economically wasteful not to extract as much value as possible from it. It is an irony that the very wood that is most desirable for manufactured wood products is being discarded as scrap for lack of a cost-effective, efficient way of extracting valuable, usable material from it. 
     Some manufacturers try to obtain at least some value for the wood left over from the material-removing processes by selling it as fuel, mulch, and/or paper chips. Using remaindered material as fuel has the disadvantage that the material has to be transported to the site where it is chipped and/or burned, thereby further reducing its already nominal value as fuel. Furthermore, there is a limit to the demand for products made from chipped wood fiber. For those reasons and the fact that there is an ever-increasing production of wood chips, chips are becoming less and less valuable as a by-product of wood-processing operations. 
     Manufacturers have for years attempted to solve the problems inherent in the utilization of remaindered wood, only to discover that it is simply not economically feasible to process material that comes in a range of widths, thicknesses, lengths, or irregular shapes. Such material requires multiple handling and processing steps to convert it into a more workable uniform and valuable product. The only known apparatus on the market for easily and economically converting scrap wood to usable dimensioned stock is a machine designed and constructed by the inventor of the present invention and that has been available for several years. This machine, the YIELD PRO Recovery machine, converts slabs, sawmill and ripsaw edgings, waney stock, and other mis-sized or random-shaped materials into uniform square-edged stock. The YIELD PRO Recovery machine is a large and rugged machine that has separate tool spindles and motors for the horizontal cutting tool and the vertical cutting tool, respectively, a lifting jack with several linear guides on each side of it, as well as a third motor for driving conveyors. This machine is capable of processing slab wood of sizes up to 4″ by 12″, can remove up to one inch of material from the top, and can even process material that has nails embedded in it. Because of its ruggedness, however, and its ability to handle large pieces of wood, this high-volume machine is relatively costly to manufacture and, thus, to acquire. Furthermore, because of its relatively large footprint, requires a lot of floor space. 
     Primary operations in the wood-products industry include such operations as sawing boards from logs in sawmills; secondary operations include such operations as turning round stock and cutting relatively small component pieces. Although primary operations are the largest source of remaindered material suitable for recovery processes, secondary operations such as furniture-making also provide significant amounts of remaindered material suitable for recovery. Currently, the remaindered material from secondary operations, as well as from primary operations, is treated as waste material and is funneled into the waste stream to be chipped and/or burned. 
     The remaindered material from secondary operations is generally even more valuable then that from primary operations. For example, in furniture-making operations, the material is likely to be kiln-dried wood that has been through any number of shaping and forming operations. The particular difficulty with recovering usable material from the remaindered material from secondary operations is that the dimensions of this material are typically much smaller than the remaindered material generated by primary operations. On the other hand, a machine that is as rugged as the YIELD PRO Recovery machine described above is not necessary to process the remaindered material generated by secondary operations. For example, wood from furniture-making operations will not have nails embedded in it; also, such wood will not be covered with bark and, therefore, less material will need to be removed from the top. Furthermore, remaindered material from secondary operations will also generally be shorter in length than much of the remaindered material from a sawmill. 
     For these reasons, a machine that is less expensive to manufacture and that is small enough that it can be moved around to different work stations in a plant, and that requires less energy to operate, will be more desirable to potential buyers and, therefore, pose a lower threshold for manufacturers to overcome if they are otherwise enticed by economics and/or environmental or other concerns to recover more material for higher value-uses than the burning of it for fuel. 
     One aspect that is critical to proper operation of the material-recovery apparatus is its feed system. When material is fed into a machine to be cut by material-removing tools, the tendency is for the material to be kicked back from the rotating cutters that resist the advance of the material. For this reason, the feed conveyor is provided with a surface that prevents material from slipping in the direction opposite to the feed direction, and feed rollers are mounted on the machinery to keep the material pressed against the conveyor. The feed rollers on the conventional machinery are attached to bearing-mounted tensioning units that apply a downward biasing force to the feed rollers. When the material feeds into the machine, these feed rollers are forced upward against the biasing force by the in-feeding material. The apparatus is designed so that the rollers accommodate the material, yet maintain sufficient downward force on it to ensure that it is carried into the cutting tools. Conventional tensioning units use a bearing-mounted spindle, around which a tensioning spring is coiled. A disk having a plurality of evenly-spaced holes around its outer perimeter is mounted at one end of the tensioning spindle. By turning the disk and inserting a locking pin into one of the holes, one moves the disk so as to bias it to apply a torque in one direction, while it remains free to rotate in the opposite direction if a force strong enough to overcome the biasing torque is applied to it. The disadvantage of the conventional tensioning unit is that, because of the machining and the amount of material necessary to provide a secure mount, it is quite expensive to manufacture. 
     What is needed, therefore, is material-recovery apparatus that is easy to operate, readily portable, and relatively inexpensive to manufacture. What is further needed is such apparatus that will accept material of various widths, thicknesses, lengths, and irregular shapes, and produce a square-edged product with a single pass of the material through the apparatus. What is yet further needed is such apparatus that is easily adjustable so as to produce square-edge stock in a range of sizes and relative dimensions. And, finally, what is needed is such apparatus that requires less power to operate and less maintenance. 
     BRIEF SUMMARY OF THE INVENTION 
     For the above-cited reasons, it is an object of the present invention to provide material-recovery apparatus that is mechanically uncomplicated, easily portable, economical to manufacture, and that requires a minimum time for set-up and maintenance. It is a further object to provide such apparatus that can accept material of various dimensions and irregular shapes and produce a square-edged product with a single pass of the material through the apparatus. It is a yet further object to provide such apparatus that is easily adjustable and can produce square-edged product in a range of varying dimensions. 
     The objects are achieved by providing material-recovery apparatus that is small in size and light enough to be easily portable, is made up of mechanically simple components, is energy-efficient and versatile, requires little effort to set up, operate, and maintain, and that produces uniform dimensioned stock from remaindered material of irregular dimensions and shapes. The apparatus according to the invention has a single tool spindle driven by a single motor. The single spindle supports two cutting tools that perform two different machining tasks simultaneously—the planing of the top face and the sawing of the outside edge of the material being processed. As the remaindered material is fed into the apparatus, feed rollers placed before and after the tool spindle bear down on the material and press it against a feed conveyor that forces it through the cutting operation. 
     The referenced feed rollers are forced down against the material on the conveyor by tensioner units that are designed so as to allow the rollers to adapt to varying thicknesses of an in-feeding workpiece while yet reliably holding the workpiece against the feed conveyor for feed and cutting operations. These tensioner units are the heart of the invention and are quite different from their counterparts in the Yield Pro prior art. Each tensioner unit is constructed of simple components that make it less expensive to construct than the known bearing-mounted tensioner units. Furthermore, the new tensioner unit according to the invention is easy to maintain and is effective in applying a downward pressure onto the workpiece feeding into the cutting operation, even if the workpiece varies in thickness and shape, or each workpiece varies from the others being processed. 
     Remaindered material such as that produced in a sawmill or in a plant that produces moldings or blanks for round stock—for example, broom handles or dowels—includes pieces of slab wood, waney stock that has a diminishing dimension such as thickness or width or both, edgings, irregularly shaped pieces such as molding, and wood that has an unacceptable or unworkable section. Generally, such remaindered material has two flat faces that intersect perpendicularly to one another. It is this type of material that can be processed into usable stock with a single pass through the apparatus according to the present invention. Remaindered material that has only one flat surface requires two passes through the apparatus to produce four-sided square-edged stock. 
     One of the key features of the new recovery apparatus is its simplicity. As mentioned above, it requires but a single-spindle machine driven by a single motor. Horizontal and vertical cutting tools are mounted on this single tool spindle to provide simultaneously two right-edged cuts along the top and the left vertical surface, respectively, of the workpiece fed through the apparatus. The housing that supports the feed rollers and the tool spindle of the new apparatus is shorter than that of the prior art and is supported, guided, and horizontally balanced by a single lifting jack, without linear guides. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates the recovery of valuable blanks from some exemplar workpieces of remaindered material by a single pass of the remaindered material through the Preferred Embodiment of the apparatus. 
     FIG. 1B illustrates the recovery of valuable blanks from some exemplar workpieces of remaindered material that require two passes of the remaindered material through the Preferred Embodiment of the apparatus. 
     FIG. 2 is a schematic illustration of the Preferred Embodiment of the apparatus according to the present invention. 
     FIG. 3 is a plan view of one feed roller and tensioner unit of the Preferred Embodiment according to the invention. 
     FIG. 4 is an illustration of the tensioner unit of the Preferred Embodiment according to the present invention. 
     FIG. 4A is an elevational view of the tensioner disc of the Preferred Embodiment according to the invention. 
     FIG. 5 shows the Preferred Embodiment of the height limiting device according to the invention. 
     FIG. 6 illustrates the production of a square-edged blank in a single pass through the Preferred Embodiment of the material-recovery apparatus of the invention. 
     FIG. 7 is an illustration of the single lifting jack of the Preferred Embodiment according to the invention. 
     FIG. 8 shows the input end of the Preferred Embodiment of the apparatus according to the invention. 
     FIG. 9A is a perspective view of the rear of apparatus of the Preferred Embodiment. 
     FIG. 9B is a perspective view of the front of the Preferred Embodiment. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIGS. 1A and 1B illustrate some of the types and shapes of remaindered material that can be converted into the usable blanks or stock by the apparatus of the present invention. As shown in FIGS. 1A and 1B, the remaindered material includes wood that is irregular in shape, that has an outer surface of bark, or is what is called “waney” stock, that is, wood having one or more dimensions that vary along the piece. FIG. 1A shows material that, prior to processing through the apparatus of the present invention, has two flat sides that are perpendicular to each other. This will allow usable blanks to be recovered from remaindered material in a single operation. Material shown in FIG. 1B has initially only one flat surface and will have to be processed in a two-step operation to convert it into rectangular blanks. Each of the recovered blanks shown in FIGS. 1A and 1B are uniform in dimensions and can be used to produce rectangular-dimensioned lumber or turned to produce spindles, dowels, handles, etc. 
     FIG. 2 is a schematic diagram of a recovery apparatus  10  according to the present invention. The recovery apparatus  10  comprises a machine base  6 , a single lifting jack and stabilizing guide assembly  5 , a housing  33  and a support bed  38 . A feed conveyor  2  is mounted on the bed  38 . A waste conveyor  7  is mounted on the bed  38  and runs alongside the feed conveyor  2 . For purposes of illustration, the waste conveyor  7  is not shown in FIG. 2, but can be seen in FIG. 4. A tool spindle  3 , feed rollers  9 A . . .  9 E and torque levers  11 A . . .  11 E are mounted on the housing  33 . In the Preferred Embodiment of the recovery apparatus  10 , each one of the feed rollers  9 A . . .  9 E is attached to a respective one of the five torque levers  11 A . . .  11 E and spaced along the recovery apparatus  10  between an input end  10 A and an output end  10 B of the recovery apparatus  10  so as to hold a workpiece  1  firmly in place as it is fed through the cutting operation and conveyed to the output end  10 B. Each of the feed rollers  9 A . . .  9 E is adjusted to apply a downward pressure to the workpiece  1  to keep it pressed against the feed conveyor  2  and prevent it from resisting travel under cutting tool mounted on the tool spindle  3 . In the Preferred Embodiment, the three rollers  9 A- 9 C on the input end  10 A of the recovery apparatus are adjusted so that the distance between the feed conveyor  2  and the bottom of each feed roller is increasingly smaller the closer each feed roller  9 A- 9 C is to the tool spindle  3 . 
     In the Preferred Embodiment, the first feed roller  9 A has a larger diameter than the remaining feed rollers  9 B- 9 E and exerts the greatest amount of downward force on the workpiece  1 . The larger diameter provides a more advantageous ratio of the horizontal to vertical force components exerted on the first feed roller  9 A when the workpiece  1  is initially fed into the recovery apparatus  10 . In other words, because of the more gradual curvature of the larger diameter, the operator must apply less horizontal force to the workpiece  1  to force this first feed roller  9 A in a vertical direction than if it had a smaller diameter. The greater downward force of the first feed roller  9 A is required to provide sufficient traction of the workpiece  1  on the feed conveyor  2  to prevent the workpiece  1  from resisting forward feed. The remaining feed rollers  9 B- 9 E can be smaller in size and apply less force to the workpiece  1 , as they are operating either in cooperation with other feed rollers or, in the case of the fifth feed roller  9 E, do not need to apply force to the workpiece  1  to force it under another roller. 
     FIG. 3 shows a feed roller  9  and a torque lever  11  that are representative of the feed rollers  9 A . . .  9 E and torque levers  11 A . . .  11 E, respectively. A tensioner unit  12  includes the torque lever  11 , a torque spring  14  wound around a tensioner shaft  19 , a tensioning disc  15 , and a tensioner unit mounting plate  18 . Grooves  15 A, sized to receive a locking pin  16 , are arranged around the outer circumference of the tensioning disc  15 . The torque spring  14  has a first spring end  14 A that is fixedly attached to the tensioning disc  15  and a second spring end  14 B that is fixedly attached to the tensioner unit mounting plate  18 . The feed roller  9  has a roller end  9 ′ that is rigidly and fixedly attached to the torque lever  11  at a first end  11 ′ of the torque lever  11 . In the Preferred Embodiment, the tensioner shaft  19  extends through a first wall  30  of the housing  33  (shown in FIG. 4) and is rigidly and fixedly attached to an adjusting device  17 . The adjusting device  17  in the Preferred Embodiment is a hexagonal head that can be grasped and turned with a wrench. 
     The tensioning disc  15  rotates freely about the tensioner shaft  19 . When the adjusting device  17  is turned in a counterclockwise direction, the spring  14  is wound tighter about the tensioner shaft  19  and exerts a biasing torque on the tensioner unit mounting plate  18  and on the feed roller  9 , pressing the feed roller  9  downward. When the desired amount of torque is applied to the feed roller  9 , the locking pin  16  is inserted through an appropriately sized aperture in the first wall  30  and seated in one of the grooves  15 A on the tensioning disc  15 , thereby preventing the tensioning disc  15  from unwinding about the tensioner shaft  19  and relieving the torque that is applied to the feed roller  9 . 
     FIG. 4 shows the housing  33 , the tensioner units  12 , the feed rollers  9 A- 9 E, the torque levers  11 A- 11 E, the feed conveyor  2 , the waste conveyor  7 , the tool spindle  3 , a vertical cutting tool  4 A and a horizontal cutting tool  4 B. Also indicated in FIG. 4 is the placement of a dust curtain  41  and an anti-kickback shield  42 . The dust curtain  41  is a wire mesh curtain that aids in retaining the dust in an area that is cleaned by a dust evacuation system. The curtain  41  and anti-kickback shield  42  are devices that are well-known in the field and are not described here in detail. Also, the dust evacuation system is provided by the operator of the recovery machine and is not included within the scope of the invention. 
     FIG. 4A shows the tensioning disc  15  in detail. The disc  15  is mounted on the tensioner shaft  19  and grooves  15 A are evenly spaced around the outer perimeter of the disc  15 . 
     FIG. 5 shows a height limit device  32  that is mounted on the second wall  31  of the housing  33  and limits the amount of downward force applied to the feed rollers  9 . In the Preferred Embodiment, the height limit device  32  includes a threaded rod  34  that is threaded through a threaded bore in a bolt  35  that is rigidly and securely fastened to the second wall  31  of the housing  33 . The threaded rod  34  can be adjusted so that the lower end of the rod  34  is higher or lower. The torque lever  11  is a rigid, non-flexible device, and thus, as greater torque is applied to the torque lever  11 , the first end  11 ′ of the torque lever  11  is forced downward and, consequently, the second end  11 ″ forced upward. The threaded rod  34  is adjusted such that it prevents the second end  11 ″ of the torque lever  11  from swinging upward past a certain distance and thereby applying too great a downward force to the feed roller  9 , which, in turn, may prevent the workpiece  1  from traveling forward into the cutter blades. 
     FIG. 6 is an elevational view of the tool spindle  3 , the vertical side cutter  4 A, the horizontal top cutter  4 B, and the cutter shield  3 A. As can be seen, the workpiece  1 , an irregularly-shaped piece, is moving past the cutting tools  4 A and  4 B which are cutting a horizontal top surface  1 C and a vertical side surface  1 D to form a new blank  1 A. The new blank  1 A is carried through the recovery apparatus  10  to the output end  10 B on the feed conveyor  2 . At the same time, scrap material  1 B left over after the cut is carried away on the waste conveyor  7 . 
     FIG. 7 shows a cross-sectional view of the single lifting-jack and stabilizing guide assembly  5  as indicated by the cut-line VII in FIG.  2 . The lifting jack and stabilizing guide assembly  5  connects the housing  33  with the bed  38  of the recovery apparatus  10  and is used to adjust the height of the housing  33  to obtain a specified thickness of stock at the output end  10 B of the recovery apparatus  10 . As can be seen in FIG. 7, a threaded rod  53  is fixedly mounted in one of a pair of bevel gears  54 . The other bevel gear is attached to a mounting plate  51  that is mounted on the outside of an outer tube  56 . Connected to the pair of bevel gears  54  is a crank handle  52 , which, when turned, causes the threaded rod  53  to rotate. The upper end of the threaded rod  53  is threaded through a bore in a stabilizing nut  58  that is fixedly mounted on the inside of an inner tube  55 . The inner tube  55  and the housing  33  are fixedly and rigidly connected to each other by means of a bearing plate  61 . When the threaded rod  53  rotates, the inner tube  55  is raised or lowered, thereby adjusting the vertical distance between the tool spindle  3  and the bed  38  and, thus, the feed conveyor  2 . A vertical scale  66  is mounted on the bed  38  to indicate the final thickness of the workpiece  1  after it has passed the horizontal tool  4 B. 
     In order to ensure that the horizontal and vertical. cuts on the workpiece  1  are square-edged, that is, perpendicular to one another, it is critical that the bed  38  and the housing  33  be held in perfect alignment relative to one another. This is achieved by supporting the inner tube  55  on a plastic poured bearing  57  that is poured into the outer tube  56 . The bearing  57  provides sufficient clearance between the bearing surface and the inner tube  55  to allow the inner tube  55  to slide along the bearing  57 , yet is close enough to the inner tube  55  to maintain perfect alignment of the inner tube  55  with the outer tube  56 . The length of the recovery apparatus  10  in the Preferred Embodiment is short enough so that the bed  38  is not cantilevered a distance that requires additional support and leveling mechanisms other than the poured bearing  57  in the lifting jack and stabilizing assembly  5 . 
     The lifting jack and stabilizing guide assembly  5  of the Preferred Embodiment is strictly manually powered, that is, is operated by means of the crank handle  52 , without any pneumatic and hydraulic power-assists. This is primarily for reasons of economy. Indeed, the Preferred Embodiment of the recovery apparatus  10  is a small-sized machine that accepts a workpiece up to eight inches in width by two and one-half inches in thickness. Because of the small size of the Preferred Embodiment of the recovery apparatus  10 , it is not necessary to provide power assistance for lifting. It is, of course, possible, to equip the recovery apparatus  10  according to the invention with a pneumatic or hydraulic power-assisted lifting jack and stabilizing guide assembly  5  and this may be desirable if pneumatic or hydraulic power is already available at the site where the recovery apparatus  10  is installed. 
     FIG. 8 shows an input end  10 A of the recovery apparatus  10  according to the invention. In the Preferred Embodiment, the input end  10 A is enclosed for safety reasons. A fence guide  68  is movably mounted on the bed  38 . Mounted on the enclosure is a mechanical cam locking device  69  with handle that is used to adjust the finish width, that is, the horizontal distance between the vertical cutter  4 A and the fence guide  68 . A horizontal scale  67  is mounted on the bed  38  to indicate the finish width of the workpiece  1 . 
     FIGS. 9A and 9B show the rear view and the front view, respectively, of the Preferred Embodiment of the recovery apparatus  10 , with the housing  33  enclosed in a safety hood  71  and drive belts within belt shrouds  72 . Such safety hoods and shrouds are well-known in the art and are not further described herein. As can be seen, a motor  62  drives the tool spindle  3  and a motor  64  the conveyor belts. The sole support and alignment of the housing  33  and the bed  38  of the recovery apparatus  10  is provided by the lifting jack and stabilizing assembly  5 , of which only the inner tube  55  and outer tube  56  are visible when the recovery apparatus  10  is in operation. 
     While a Preferred Embodiment is disclosed herein, this is not intended to be limiting. Rather, the general principles set forth herein are considered to be merely illustrative of the scope of the present invention and it is to be further understood that numerous changes may be made without straying from the scope of the present invention.