AU2003200528B2 - Method and apparatus for profiling a log - Google Patents

Description

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT Name of Applicant: Actual Inventors: Address for Service: Invention Title: Key Knife, Inc.

STAGER, Bradley, R.

LUECKE, John, S.

DAVIES COLLISON CAVE, Patent Attorneys, 1 Little Collins Street, Melbourne, 3000 Method and apparatus for profiling a log The following statement is a full description of this invention, including the best method of performing it known to us.

Q:\OPER\ARL\FEB\261431I 44.DOC- 14/2/03 METHO0D ANrD APPARATUS FOR PROFILING A LOG The present invention relates to a miethod and apparatus for profiling a log, pirticularly for cutting a reentrant corner in the log that cxtcnds along the log.

To process log~s into standard lumiber, the logs arc first slabbed on one to four sidcs. To avoid wastc and. bccause the cross-scction orthic beL is generally round, this processing inrentionallyileaves four rounded coomcrs, Refer-ig first to Figures I A an d 1B depicting. respectively, the cross-section of the before and aftcr being slabbed onl four sides and then turning td Figure I C, the rounded corners arc remloved by cutting into the log along its longitudinal axis corresponding reentrant corners This squares portions of the log. indicated in the Figure as that are located the contoturs of adjacent comners so that the portions are configured to be cut into pieccs of standard lumiber. Fornling the corners C is typically referred to as .profiling" and an apparatus adapted for this purpose is typically referrcd to as a An example of a prior art profler is shown in Figure 2. First and second kives 21 and 4, which arc identical, are disp osed on the circumference of a rotating disc 6. A slabbed log 8 ha%-ing anl elon-ate axis is fed toward the disc along a circumferential direction Thle cutting ed-c of the first knife is oriented parallel to the axis of rotation of the disc and the cutting edgc of the second knife is oricnted in a plane of rotation of the disc. Referring back to Figure I C, the first knife cuts a first le- I I of a particular recntrant corner C and the second knife cuts a pcrpendicular, secondleg- "12" of the reentrant corner, whercin the legs 11 and 12 mecet at a region of intersection "cl" of the corner C. It should be understood that the legs "it" and "12" are the visible portions of planar surfaccs extending along the longitudinal axis of the log.

Another example o f 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 movcment between the disc and the log, this time difference provides an opportunity for the two cuts to fail to intersect precisely at the same comer region c I and thereby fail to form a clean or smooth comer C. In particular, there often results, running longitudinally along the comer C, "feathers" or slivers of wood partially but not completely removed from the log. or other unevenness in the surface texturc 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 comers cut thereby and for maintaining this capability despite wear in the apparatus.

The present invention provides a knife for use in a wood profiling apparatus, said knife being mounted for rotation about an axis in said profiling apparatus, said knife including first and second sides which meet to define a cutting edge, and a third side immediately adjacent the cutting edge and the first and second sides, wherein the cutting edge is at an angle with respect to said third side that differs substantially from 900.

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 advantageous feature 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 one embodiment of the present invention to provide a novel and improved knife for use in a method and apparatus for profiling a log or other elongate article.

P:\OPER\Arl\2614311 claims.do-13/07/04 -3- It is another object of one embodiment of the present invention to provide a knife for such a method and apparatus that provides for the formation of smoother surfaces in corners cut thereby.

It is still another object of one embodiment the present invention to provide a knife for such a method and apparatus that provides for maintaining the aforementioned capability despite wear in the apparatus.

Preferred embodiments of the invention will now be described, by way of examnple only, with reference to the accompanying drawings, as set out below.

Figure 1A is a cross-section of a log.

Figure 1B is a cross-section of the log of Figure 1A after having been slabbed.

Figure 1C is a cross-section of the log of Figure 1B 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, 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 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.

IA profiling apparatus 10 is shown in Fi-urcs 3% and 4. Tile profiling apparatus is particularly adapted for profiling a log; however, it may be cniploycd for profiling any elon-ate article. The ten'n "profiling" means fundamentally to alter tile shape of thle article for sonic productive purpose.

Referring back to Figures l B and I C, typically, this involves altering an elongate forin such as the rounded corner 'Cround" of a slabbed lot, into anl elongatc, reentrant, square corner This configures tile material indicated in Figure I C as which lies between the contours of neigh1boring corners C into an orthorhomnbic confi ,uration. or "squarcs" the miaterial. It should be borne in mind throughout that other reentrant shapes could be formled, or comers could be formied having other angles varying from 90 degrees, w\here that is dcsirabkc and thle -operation could bc performed onl clongate articles other than logs without departing from thle principles 'of the invention.

ReferringV to Figure 3, a rotor 12 is provided with a desired number of mounting members 14, such as four, Thle rotor may be disc sha~ped or it may have somnicrnative configuration such as that shown. As shown in both Figures 3 and 4, the rotor rotates about anl axis As in Figure 2, a stabbed log 8 having an elongate axis is fed toward the rotor along a circumferential direction which is represented in Figure 4 and whiich is perpendicular to the plane of Figure Each mountintt member 14 includes two holders 16 and IS. Each holder is adapted to clamip an associated knife 17 and 19 to the mounting member. The knives may be any cutting implemients 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 thle 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, Howvever, it is often prcfcrabic to provide these components as individual parts that are adapted to be connected together with machine screws or bolts.

3 0 The holders 16 and I S are adapted for clamping tileir -respcctivC knives to the mounting elerricnlt anid for releasing thle knife to allow the knife~ to be removed therefrom. Any of a number of prior art holders may b.e employed. A particularly advantagcous holder IS that describcd in U.S. Patent No. 5.979,522. which is shaped to fit knivcs marketed by Key Knlife, Inc.. under the trademark KEYKNIFE.

Figure 5 presents a morc detailed vicw of a preferred mountintg memibcr 14 as showo in Figure 3. The kilives 1 7 and 19 have respective cutting edges 20 and 22.

Thic knife 17 is mrountcd by the holder 16 to the mounting memilber 14 so that the cuttng edgc 20 extends parallel to thc rotational axis of the rotor. The knife 19 is mounted by the holder IS to thle 1 ouLntinl- mIcmber SO 1li.1t thle cuttingd cd 2? lies in a plane of rotation of the rotor. The cuttin- cd-es 20 and 22 wre typically disposed to formn a 90 degree agetherebetween, for cuttino a squarc corner C.

Referring particularly to Fig'ure 5. the knives are preferably adapted so that a back side of the knife 17 abuts u side surface 25 of the kniife 19 to form~ a mitered corner. For this puirpose, the side surface 25 of the knife 1 9 is angled obliquely with respect to thc cuttin- cdge 22, and For cutting oppositQ cormers C. left and right handed versions of the angle and, therefore, the knife 19 may be provided.

Thc cutting edges define lines composed of a number of points. Cutting action by) cachi knife creates respective surfaces, typically though not necessarily planes, as a result of the cutting edges progressing through thle work as a result of relative mlovemecnt there between. Similarly, cultin action resulting from a particular point oil a cutting edge creates a line, typically though not necessarily straight, as a result of the reClative mlovementm. In thec Instant invention, the mounting memnber is configured so that at least one of the points on one of the cutting ed.-es is proximate at least one of the points onl the other of the cutting edges. Preferably, these points are end points of the respective cuttingc edges and, preferably, these points abut one another, such as shown in Figure 4.

Particularly, where thle cuttingz edges arc brought into proximate coincidencc at their end points their tips, it has been found that this coincidence is preferably no miore than about 1/8" for notuble minimlization of surface irregularities such as "wvaviness" and feathers, with 1/ 16" being a rnorc desirable outer limit for commercial practice. It has also been found that decreasing thc chip size gencrally permiits a larger separation between the points for purposes of minimizing waviness, but thle gencration of feathers is not Substantially affected. Neither waviness nor the generation of feathers is substantially affected by the sixe of the knives.

In iddition to recognizing that it is important to irrange the knives in a close tipto-tip relationship to improve cutting finish. the present inventors have also recognized thc importance of providing for maintaining such a relationsitip during USC Of th c apparatus. A chipping kjilfc is typically clamped to a mounting member by a knife S holder. e bolt extnirding through the knife holder into either the mounting nicmibcr or tile rotor. During usc of thc apparatus, the bolt may loosen, allo-wing thc knife some latitudc to slip ba-ckwarttdly from te ldirccrion-ofrotartion. WheCTCtwo knives that were arranged inl tip-to-tip abutting relationship slip inl unequal amounts, a gap develops therebctNccn. Moreover, any gap so formed may become packed with debris fromi thc 3.o log. the packing causing the knives to spread fuirthcr and further apart from o!re another during continued use.

Corresponding mating features are provided in the 'knives 17.and 19 and the mounting miember 14, to substantially lock the knivecs into a selected position with respect thereto. for maintaining in nbutting relationship of thc tips of thle kilves c\,cn when the clamnping force for holding thc knife exe rted by the holders 1 6 and I S to thle niounting memnber is reduced to zero.

Ficlure 5 shows n prefetred structure for this purpose, In the prcferred structure, the knives 1 7 and 1 9 eachi include it kecyway 15, and the mounting mcmber 14 includes corresponding keys 32 and 34 that are ada3pted to fit closc]\. the keyways 15 of the knives.

2 0 The kevwtNvs and keys 32 and 34 are adapted so that interlocking the keyways and the keys prevents niovermri of thc knives in a direction perpendicular to their cutting edges, or in the direction of rotation of the mounting member. In the preferred structure, the keywa-ys arc slots formed in the knives cxtendintg parallel to the cutting cdgcs of the knives as shown and described more fully in Carpenter ct al.. U.S. Patent No. 4,S5O,408, 2 5 incorporated by reference herein in its entirety.

Providing for locking the knives to the mounting member rather than tile holders 1 6 and 18 maintains their relative positions. The holders arc subject to loosening because they are particularly adapted to apply a clanmping force to ithe knives which must be removable in order to rcplace 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 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 that is substantially along the longitudinal axis of the log. The grain of the log is defined approximately by a series of concentric cylinders having their axes in the direction The rotor 12 is shown provided with three mounting members 14, and the axis of rotation of the rotor is perpendicular to the direction In cutting the log along its travel direction the knives enter the log at point reach a maximum depth of penetration at point and exit the log at point The inventors have recognized that for cutting clean and sharp corners 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 This is to avoid "pulling up" the fibers making up the grain.

As it is decpicted in Figure 6, the knife 17 extends into the plane of the paper and, therefore, its cutting cdgc 20 is always perpendicular to the grain. However, the anglec the kjiife edge 22 makes with respect to thc grain changes along- its path from to to 'F"This canl bc appreciated by comparing Figures 7 and S. In both Figure 7 and Figure 8, the knives 1 7 and 19 are shown in aI configuration for cutting square corners whercin the angle 19 between the edges 20 and 22 is 90 degtrees. However. in Figure 7, Elie knives are showni relative to the log travel direction as they would appcar at poin while in Figure S, the knives are shown relative to as they would appear at point iv Figure 6. At point (Figure both of thle curtim, ediges 20 and 22 are 1 0 perpendicular to the travel dircction and therefore perpiendicular to the arain.

,Ho%%cvcr. at point (Figure the cutting edge 22 is parallel to the grain. This is undesirable.

Turnling to Figure 9, the present embodiment provides a selected angle between thec cuttimi edgec. 22 and thle line defined as being perpendicular to thie travel directionl and the axis of rotation at point As best seen in Figure 6, the angle (D is preferably determined by constnicting a radial line extending from the tips of the knives 1 7 and 19 *to the center of the rotor the samec result being obtained by projecting. inl a planc perpendicular to the axis of rotation, the line extcnding from the tips. of tile knives to any point on the axis of rotation.

Anl angular variation of the angle 0 about the tips of thle knives is preferably within about 15 degrees. As can be appreciated by inspecting Figure 6 and considering the goal of minimizing parallelism wvith the grain it is -enerally desirable that thie angle (D be greater where the depth of penetration into the log (FiglUre as compared to the radius of the arc traveled by the tips of the knives, is greater.

The consideration of the angle cZD is substantially independent of the choice of the anglie 0. For ex'ample, the projections of the cutting edges 20 and 22 in the direction of rotation of thle mounting member 14 that is responsible for the shape of the comner "C" (Figure remain 90 degrees apart regardless of the choice of the angle (D.

It is to be recognized that, while a particular knife for use in method and apparatus for profiling a log has been shown and described as preferred, other configurations could be utilized, in P:\OPER\AM4786-00 SPE.doc-14/02/03 -9addition 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.

Throughout this specification and the claims which follow, unless the context requires otherwise, the word "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

The reference to any prior art in this specification is not, and should not be taken as, an acknowledgment or any form of suggestion that that prior art forms part of the common general knowledge in Australia.

Claims (2)

1. A knife for use in a wood profiling apparatus, said knife being mounted for rotation about an axis in said profiling apparatus, said knife including first and second sides which meet to define a cutting edge, and a third side immediately adjacent the cutting edge and the first and second sides, wherein the cutting edge is at an angle with respect to said third side that differs substantially from 900.

2. A knife, substantially as described with reference to Figures 3-9. Dated this 13th day of July, 2004 Key Knife, Inc. By DAVIES COLLISON CAVE Patent Attorneys for the Applicant