METHOD AND APPARATUS FOR PROFILING A LOG

Abstract: A method and apparatus for profiling a log. In a profiler having first and second knives (17, 14) disposed on a rotating disc (12), a mounting member (14) is adapted to mountably receive both the first and second knives so that each blade has a point on its cutting edge that is proximate a point that is on the cutting edge of the other knives. Preferably, the points are end most points and abut one another.

Description: METHOD AND APPARATUS FOR PROFILING A LOG TECHNICAL FIELD The present invention relates to a method and apparatus for profiling a log, particularly for cutting a reentrant corner in the log that extends along the log. BACKGROUND ART To process logs into standard lumber, the logs are first slabbed on one to four sides. To avoid waste and, because the cross-section of the log is generally round, this processing intentionally leaves four rounded corners. Referring first to Figures 1A and IB depicting, respectively, the cross-section of the log before and after being slabbed on four sides and then turning to Figure 1C, the rounded corners are removed by cutting into the log along its longitudinal axis corresponding reentrant corners "C." This squares portions of the log, indicated in the Figure as "A", that are located between the contours of adjacent corners so that the portions are configured to be cut into pieces of standard lumber. Forming the corners C is typically referred to as "profiling" and an apparatus adapted for this purpose is typically referred to as a "profiler." An example of a prior art profiler is shown in Figure 2. First and second knives 2 and 4, which are identical, are disposed on the circumference of a rotating disc 6. A slabbed log 8 having an elongate axis "L" is fed toward the disc along a circumferential direction "d." The cutting edge of the first knife is oriented parallel to the axis of rotation of the disc and the cutting edge of the second knife is oriented in a plane of rotation of the disc. Referring back to Figure 1C, the first knife cuts a first leg "11 " of a particular reentrant corner C and the second knife cuts a perpendicular, second leg "12" of the reentrant corner, wherein the legs 11 and 12 meet at a region of intersection "cl " of the corner C. It should be understood that the legs "11" and "12" are the visible portions of planar surfaces extending along the longitudinal axis of the log. Another example of a prior art profiler replaces the second knife with a sequence of cutting teeth disposed around the periphery of the disc, such as the teeth of a saw blade. In both of these profilers, the first and second knives are disposed so that the first knife meets the log at a different time than does the second knife. Because there is relative movement between the disc and the log, this time difference provides an opportunity for the two cuts to fail to intersect precisely at the same corner region cl and thereby fail to form a clean or smooth corner C. In particular, there often results, running longitudinally along the corner C, "feathers" or slivers of wood partially but not completely removed from the log, or other unevenness in the surface texture of the corner. This result is often aggravated further as wear occurs in the apparatus. Accordingly, there is a need for a method and apparatus for profiling a log that provides for the formation of smoother surfaces in corners cut thereby and for maintaining this capability despite wear in the apparatus. DISCLOSURE OF -INVENTION A method and apparatus for profiling a log according to the present invention solves the aforementioned problems and meets the aforementioned needs by providing in a profiler having first and second knives disposed on a rotating disc, wherein the first and second knives have respective cutting edges defining an angle therebetween that is typically but not necessarily 90 degrees, a mounting member that is adapted to mountably receive both the first and second knives so that each blade has a point on its cutting edge that is proximate a point that is on the cutting edge of the other knife. Preferably, the points of the cutting edges that are proximate are the ends of the cutting edges and, preferably, the proximity is such that the points abut one another. Preferably, an abutting relationship of the tips of the knives is maintained against the forces typically encountered by the knives during use. The knives preferably include keyways that mate with corresponding keys in a mounting member for holding the knives. The keyways and keys substantially prevent the knives from moving in response to the forces. In another aspect of the invention, the cutting edge of at least one of the knives is angled to avoid cutting the log parallel to the grain, to further improve the surface finish in profiling the log. Therefore, it is a principal object of the present invention to provide a novel and improved method and apparatus for profiling a log or other elongate article. It is another object of the present invention to provide such a method and apparatus that provides for the formation of smoother surfaces in corners cut thereby. It is still another object of the present invention to provide such a method and apparatus that provides for maintaining the aforementioned capability despite wear in the apparatus. The foregoing and other objects, features and advantages of the present invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the following drawings. B TEF DESCRIPTION OF D AWINGS Figure 1A is a cross-section of a log. Figure IB is a cross-section of the log of Figure 1 A after having been slabbed. Figure 1C is a cross-section of the log of Figure IB after having been profiled. Figure 2 is a plan view of a first prior art profiling apparatus. Figure 3 is a partially exploded view of a profiling apparatus according to the present invention, showing a single rotor and a preferred mounting member. Figure 4 is a side elevation of the profiling apparatus of Figure 3, taken along a line 4-4 thereof, showing four rotors. Figure 5 is an exploded view of the preferred mounting member of Figure 3. Figure 6 is a plan view of a profiling apparatus according to the present invention, shown cutting a log. Figure 7 is a simplified pictorial view of two knives for use in the profiling apparatus of Figure 6, shown in a first orientation with respect to a direction of travel of the log. Figure 8 is another simplified pictorial view of the two knives of Figure 7, shown in a second orientation with respect to the direction of travel of the log. Figure 9 is a simplified pictorial view of two knives of the profiling apparatus of Figure 6, shown in a preferred configuration in the second orientation of Figure 8. BEST MODE FOR CARRYING OUT THE INVENTION A profiling apparatus 10 according to the present invention is shown in Figures 3 and 4. The profiling apparatus is particularly adapted for profiling a log; however, it may be employed for profiling any elongate article. The term "profiling" means fundamentally to alter the shape of the article for some productive purpose. Referring back to Figures IB and 1C, typically, this involves altering an elongate form such as the rounded corner "Cround" of a slabbed log into an elongate, reentrant, square comer "C." This configures the material indicated in Figure 1C as "A" which lies between the contours of neighboring corners C into an orthorhombic configuration, or "squares" the material. It should be borne in mind throughout that other reentrant shapes could be formed, or comers could be formed having other angles varying from 90 degrees, where that is desirable, and the operation could be performed on elongate articles other than logs without departing from the principles of the invention. Referring to Figure 3, a rotor 12 is provided with a desired number of mounting members 14, such as four. The rotor may be disc shaped or it may have some alternative configuration such as that shown. As shown in both Figures 3 and 4, the rotor rotates about an axis "R." As in Figure 2, a slabbed log 8 having an elongate axis "L" is fed toward the rotor along a circumferential direction "d" which is represented in Figure 4 and which is perpendicular to the plane of Figure 5. Each mounting member 14 includes two holders 16 and 18. Each holder is adapted to clamp an associated knife 17 and 19 to the mounting member. The knives may be any cutting implements including, for example, saw teeth. The mounting member is, in turn, adapted for mounting to the rotor 12. The identification of discrete parts such as the mounting member and rotor may be somewhat arbitrary since these parts could be combined into an integral unit and function identically for purposes of the present invention. However, it is often preferable to provide these components as individual parts that are adapted to be connected together with machine screws or bolts. The holders 16 and 18 are adapted for clamping their respective knives to the mounting element and for releasing the knife to allow the knife to be removed therefrom. Any of a number of prior art holders may be employed. A particularly advantageous holder is that described in U.S. Patent No. 5,979,522, which is shaped to fit knives marketed by Key Knife, Inc., under the trademark KEYKNIFE. Figure 5 presents a more detailed view of a preferred mounting member 14 as shown in Figure 3. The knives 17 and 19 have respective cutting edges 20 and 22. The knife 17 is mounted by the holder 16 to the mounting member 14 so that the cutting edge 20 extends parallel to the rotational axis "R" of the rotor. The knife 19 is mounted by the holder 18 to the mounting member so that the cutting edge 22 lies in a plane of rotation of the rotor. The cutting edges 20 and 22 are typically disposed to form a 90 degree angle therebetween, for cutting a square comer C. Referring particularly to Figure 5, the knives are preferably adapted so that a back side of the knife 17 abuts a side surface 25 of the knife 19 to form a mitered comer. For this purpose, the side surface 25 of the knife 19 is angled obliquely with respect to the cutting edge 22, and for cutting opposite comers C, left and right handed versions of the angle and, therefore, the knife 19 may be provided. The cutting edges define lines composed of a number of points. Cutting action by each knife creates respective surfaces, typically though not necessarily planes, as a result of the cutting edges progressing through the work as a result of relative movement there between. Similarly, cutting action resulting from a particular point on a cutting edge creates a line, typically though not necessarily straight, as a result of the relative movement. In the instant invention, the mounting member is configured so that at least one of the points on one of the cutting edges is proximate at least one of the points on the other of the cutting edges. Preferably, these points are end points "O" of the respective cutting edges and, preferably, these points abut one another, such as shown in Figure 4. Particularly, where the cutting edges are brought into proximate coincidence at their end points "O", i.e., their tips, it has been found that this coincidence is preferably no more than about 1/8" for notable minimization of surface irregularities such as "waviness" and feathers, with 1/16" being a more desirable outer limit for commercial practice. It has also been found that decreasing the chip size generally permits a larger separation between the points for purposes of minimizing waviness, but the generation of feathers is not substantially affected. Neither waviness nor the generation of feathers is substantially affected by the size of the knives. In addition to recognizing that it is important to arrange the knives in a close tip- to-tip relationship to improve cutting finish, the present inventors have also recognized the importance of providing for maintaining such a relationship during use of the apparatus. A chipping knife is typically clamped to a mounting member by a knife holder, e.g., a bolt extending through the knife holder into either the mounting member or the rotor. During use of the apparatus, the bolt may loosen, allowing the knife some latitude to slip backwardly from the direction of rotation. Where two knives that were arranged in tip-to-tip abutting relationship slip in unequal amounts, a gap develops therebetween. Moreover, any gap so formed may become packed with debris from the log, the packing causing the knives to spread further and further apart from one another during continued use. In accord with the invention, corresponding mating features are provided in the knives 17 and 19 and the mounting member 14, to substantially lock the knives into a selected position with respect thereto, for maintaining an abutting relationship of the tips of the knives even when the clamping force for holding the knife exerted by the holders 16 and 18 to the mounting member is reduced to zero. Figure 5 shows a preferred structure for this purpose. In the preferred structure, the knives 17 and 19 each include a keyway 15, and the mounting member 14 includes corresponding keys 32 and 34 that are adapted to fit closely the keyways 15 of the knives. The keyways and keys 32 and 34 are adapted so that interlocking the keyways and the keys prevents movement of the knives in a direction perpendicular to their cutting edges, or in the direction of rotation of the mounting member. In the preferred structure, the keyways are slots formed in the knives extending parallel to the cutting edges of the knives as shown and described more fully in Carpenter et al., U.S. Patent No. 4,850,408, incorporated by reference herein in its entirety. Providing for locking the knives to the mounting member rather than the holders 16 and 18 maintains their relative positions. The holders are subject to loosening because they are particularly adapted to apply a clamping force to the knives which must be removable in order to replace the knives. The closeness of fit between the keys and keyways is allowed to vary depending on the allowable separation of the tips of the knives. Preferably for maintaining a substantially abutting relationship of the tips of the knives, the keys should fit the keyways to a tolerance of less than about 0.015". Alternatively, other corresponding mating features in the knives and mounting member could be provided to accomplish the result of substantially locking the knives together, as will be immediately appreciated by the person of ordinary skill. For example, other shapes of keys and keyways may be provided, such as "V" shapes, ridges or ribs in either member. As a further example of keyed corresponding mating features, a pin and aperture combination could be provided. As an example of a non-keyed mating feature, a nonremovable or otherwise rigidly attached "backstop" to the knife could be employed. The backstop would be used in conjunction with the corresponding mating feature defined by the back surface of the knife as defined by the direction of rotation of the knife. Corresponding mating features may be keyed or non-keyed according to the principles of the invention. Preferably, the mounting member 14 is formed of a single piece of metal, to enhance the security with which the relationship of the knives is maintained. However, this is not essential to the advantage provided by the present invention. Turning to Figure 6, the profiling apparatus 10 is shown in a typical configuration. The log 8 is shown in elevation as traveling in a direction "d" that is substantially along the longitudinal axis of the log. The grain "g" of the log is defined by a series of concentric cylinders having their axes in the direction "d." The rotor 12 is shown provided with three mounting members 14, and the axis of rotation "R" of the rotor is perpendicular to the direction "d". In cutting the log along its travel direction "d," the knives enter the log at point "D", reach a maximum depth of penetration at point "E" and exit the log at point "F". The inventors have recognized that for cutting clean and sharp comers "C" as shown in Figure 1C, it is most advantageous to avoid cutting the wood with either of the cutting edges 20 or 22 parallel to the grain "g." This is to avoid "pulling up" the fibers making up the grain. As it is depicted in Figure 6, the knife 17 extends into the plane of the paper and, therefore, its cutting edge 20 is always perpendicular to the grain. However, the angle the knife edge 22 makes with respect to the grain changes along its path from "D" to "E" to "F." This can be appreciated by comparing Figures 7 and 8. In both Figure 7 and Figure 8, the knives 17 and 19 are shown in a configuration for cutting square corners "C", wherein the angle Θ between the edges 20 and 22 is 90 degrees. However, in Figure 7, the knives are shown relative to the log travel direction "d" as they would appear at point "D", while in Figure 8, the knives are shown relative to "d" as they would appear at point "E" in Figure 6. At point "E" (Figure 8), both of the cutting edges 20 and 22 are perpendicular to the travel direction "d", and therefore perpendicular to the grain. However, at point "D" (Figure 7), the cutting edge 22 is parallel to the grain. This is undesirable. Turning to Figure 9, the present invention provides a selected angle Φ between the cutting edge 22 and the line "s" defined as being perpendicular to the travel direction "d" and the axis of rotation at point "E." As best seen in Figure 6, the angle Φ is preferably determined by constructing a radial line extending from the tips of the knives 17 and 19 to the center of the rotor "R", the same result being obtained by projecting, in a plane perpendicular to the axis of rotation, the line extending from the tips of the knives to any point on the axis of rotation. An angular variation "v" of the angle Φ about the tips of the knives is preferably within about +/- 15 degrees. As can be appreciated by inspecting Figure 6 and considering the goal of minimizing parallelism with the grain "g", it is generally desirable that the angle Φ be greater where the depth of penetration "d c " into the log (Figure 6), as compared to the radius "r" of the arc traveled by the tips of the knives, is greater. The consideration of the angle Φ is substantially independent of the choice of the angle Θ. For example, the projections of the cutting edges 20 and 22 in the direction of rotation of the mounting member 14 that is responsible for the shape of the comer "C" (Figure 1) remain 90 degrees apart regardless of the choice of the angle Φ. It is to be recognized that, while a particular method and apparatus for profiling a log has been shown and described as preferred, other configurations could be utilized, in addition to configurations already mentioned, without departing from the principles of the invention. Moreover, there is no intention to limit the invention to use in profiling apparatus where there may be other applications involving similar considerations for which the present invention provides similar advantages. The terms and expressions which have been employed in the foregoing specification are used therein as terms of description and not of limitation, and there is no intention of the use of such terms and expressions of excluding equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims which follow.

Claims: CLAIMS 1. In a profiler having first and second knives having respective cutting edges defining an angle therebetween, a movable mounting member that is adapted to mountably receive both the first and second knives so that each knife has at least one point on its respective cutting edge that is proximate at least one point that is on the cutting edge of the other knife. 2. The mounting member of claim 1, wherein said mounting member is further adapted to mountably receive the first and second knives so that respective ends of the cutting edges are proximate one another. 3. The mounting member of claim 1 , wherein the mounting member is further adapted to mountably receive the first and second knives so that respective ends of the cutting edges abut one another. 4. A method for profiling a log or other elongate article, comprising the steps of: providing a first knife having a cutting edge; providing a second knife having a cutting edge; disposing said cutting edge of said first knife and said cutting edge of said second knife so that said cutting edges form a non-zero angle therebetween and so that at least one point on said cutting edge of said first knife is proximate at least one point on said cutting edge of said second knife; and moving said first and said second cutting edges and the log or other elongate article relative to each other to cut two surfaces in the log or other elongate article with said first knife and said second knife. 5. The method of claim 4, wherein said step of disposing includes disposing said cutting edge of said first knife and said cutting edge of said second knife so that respective ends of said cutting edges are proximate one another. 6. The method of claim 4, wherein said step of disposing includes disposing said cutting edge of said first knife and said cutting edge of said second knife so that respective ends of said cutting edges abut one another. 7. A profiling apparatus for profiling a log, comprising: a first knife having two opposite sides and a cutting edge; a second knife having a cutting edge; a mounting member adapted to receive a first side of said first knife; and a first holder adapted to apply a removable first clamping force to the second side of said first knife for clamping the knife to said mounting member, said mounting member being adapted to receive said knives so that respective tips thereof substantially abut one another, said mounting member and said first knife including corresponding mating features adapted to substantially prevent movement of said first knife with respect to said mounting member in a direction perpendicular to the cutting edge of said first knife in the event the first clamping force is reduced to zero. 8. The profiling apparatus of claim 7, wherein said mounting member has a threaded aperture corresponding to said first knife, and wherein said first holder includes an aperture adapted for passing a first bolt therethrough, said threaded aperture of said mounting member being adapted to threadingly receive the first bolt to produce said first clamping force. 9. The apparatus of claim 7, wherein said second knife has two opposite sides and said mounting member is adapted to receive a first side of said second knife, the apparatus further comprising a second holder adapted to apply a removable second clamping force to the second side of said second knife for clamping the second knife to said mounting member, said mounting member and said second knife including corresponding mating features adapted to substantially prevent movement of said second knife with respect to said mounting member in a direction perpendicular to the cutting edge of said second knife in the event the second clamping force is reduced to zero. 10. The apparatus of claim 9, wherein said mounting member has a threaded aperture corresponding to said first knife and another threaded aperture corresponding to said second knife, wherein said first holder includes an aperture adapted for passing a first bolt therethrough and wherein said second holder includes an aperture adapted for passing a second bolt therethrough, said threaded apertures of said mounting member being adapted to threadingly receive the respective bolts to produce said first and said second clamping forces. 11. The profiling apparatus of claim 10, wherein said keyways in said knives include slots extending parallel to the respective said cutting edges and wherein said keys are adapted to fit closely said keyways. 12. The profiling apparatus of claim 7, wherein the profiling apparatus is adapted to pass said knives through an article of wood by feeding the article of wood against the knives in a feed direction perpendicular to said axis of rotation, wherein said knives reach a point of maximum depth of penetration into the wood, wherein the cutting edge of one of said knives is parallel to said axis of rotation and the cutting edge of the other of said knives has a projection, in a plane perpendicular to said axis of rotation, that makes an angle with a line that is both perpendicular to said feed direction and said axis of rotation that is substantially greater than zero. 13. The profiling apparatus of claim 12, wherein the cutting edge of one of said knives is parallel to said axis of rotation and the cutting edge of the other of said knives has a projection, in a plane perpendicular to said axis of rotation, that lies along a line defined by first and second points within an angular variation about said first point of about plus or minus 15 degrees, wherein said first point is defined by the tips of said knives and said second point lies on said axis of rotation. 14. A profiling apparatus for profiling a log, comprising two knives, said knives having respective cutting edges, the profiling apparatus being adapted for rotating said knives about an axis of rotation, wherein the profiling apparatus is adapted to pass said knives through an article of wood by feeding the article of wood against the knives in a feed direction perpendicular to said axis of rotation, wherein said knives reach a point of maximum depth of penetration into the wood, wherein the cutting edge of one of said knives is parallel to said axis of rotation and the cutting edge of the other of said knives has a projection, in a plane perpendicular to said axis of rotation, that makes an angle with a line that is both perpendicular to said feed direction and said axis of rotation that is substantially greater than zero. 15. The profiling apparatus of claim 14, wherein the cutting edge of one of said knives is parallel to said axis of rotation and the cutting edge of the other of said knives has a projection, in a plane perpendicular to said axis of rotation, that lies along a line defined by first and second points within an angular variation about said first point of about plus or minus 15 degrees, wherein said first point is defined by the tips of said knives and said second point lies on said axis of rotation. 16. A profiling apparatus for profiling a log, comprising two knives, said knives having respective cutting edges, the profiling apparatus being adapted for rotating said knives about an axis of rotation, wherein the cutting edge of one of said knives is parallel to said axis of rotation and the cutting edge of the other of said knives has a projection, in a plane perpendicular to said axis of rotation, that lies along a line defined by first and second points within an angular variation about said first point of about plus or minus 15 degrees, wherein said first point is defined by the tips of said knives and said second point lies on said axis of rotation. 17. A method for profiling a log, comprising providing a mounting member adapted for rotation about an axis and adapted to receive at least two knives, the knives having respective cutting edges, the method comprising clamping the knives to the mounting member so that the cutting edges of the knives make an angle with respect to one another and so that respective tips of the knives abut one another by applying a clamping force, and providing in the mounting member and in the knives corresponding mating features for substantially preventing movement of the knives in the direction of rotation of the mounting member in the event the clamping force is reduced to zero. 18. The method of claim 17, further comprising passing the knives through an article of wood by feeding the article of wood against the knives in a feed direction perpendicular to the axis of rotation, wherein the knives reach a point of maximum depth of penetration into the wood, orienting the cutting edge of one of said knives to be parallel to the axis of rotation, and providing that the cutting edge of the other of said knives has a projection, in a plane perpendicular to the axis of rotation, that makes an angle with a line that is both perpendicular to the feed direction and the axis of rotation that is substantially greater than zero. 19. The method of claim 18, further comprising orienting the cutting edge of one of the knives to be parallel to the axis of rotation and providing that the cutting edge of the other of the knives has a projection, in a plane perpendicular to the axis of rotation, that lies along a line defined by first and second points within an angular variation about said first point of about plus or minus 15 degrees, wherein said first point is defined by the tips of said knives and said second point lies on said axis of rotation. 20. A method for profiling a log, comprising providing a mounting member adapted for rotation about an axis and adapted to receive at least two knives, the knives having respective cutting edges, the method comprising passing the knives through an article of wood by feeding the article of wood against the knives in a feed direction perpendicular to the axis of rotation, wherein the knives reach a point of maximum depth of penetration into the wood, orienting the cutting edge of one of said knives to be parallel to the axis of rotation, and providing that the cutting edge of the other of said knives has a projection, in a plane perpendicular to the axis of rotation, that makes an angle with a line that is both perpendicular to the feed direction and the axis of rotation that is substantially greater than zero. 21. The method of claim 19, further comprising orienting the cutting edge of one of the knives to be parallel to the axis of rotation and providing that the cutting edge of the other of the knives has a projection, in a plane perpendicular to the axis of rotation, that lies along a line defined by first and second points within an angular variation about said first point of about plus or minus 15 degrees, wherein said first point is defined by the tips of said knives and said second point lies on said axis of rotation. 22. A method for profiling a log, comprising providing a mounting member adapted for rotation about an axis and adapted to receive at least two knives, the knives having respective cutting edges, the method comprising orienting the cutting edge of one of the knives to be parallel to the axis of rotation and providing that the cutting edge of the other of the knives has a projection, in a plane perpendicular to the axis of rotation, that lies along a line defined by first and second points within an angular variation about said first point of about plus or minus 15 degrees, wherein said first point is defined by the tips of said knives and said second point lies on said axis of rotation.

Inventors: LUECKE JOHN S, STAGER BRADLEY R, LUECKE, JOHN, S., STAGER, BRADLEY, R.
Applicants: KEY KNIFE INC, LUECKE JOHN S, STAGER BRADLEY R, KEY KNIFE, INC., LUECKE, JOHN, S., STAGER, BRADLEY, R.
Application year: 2000
Main classification: B27M
IPC codes: B27L11