Patent Grant
9731365
The present invention relates to saw blades, and more particularly, relates to metal-cutting saw blades, such as band saw blades or hole cutters, for cutting difficult-to-cut materials.
One of the drawbacks of prior art band saw blades, particularly band saw blades that are used to cut difficult-to-cut materials, such as tool steels, stainless steels, nickel-based alloys, or other hardened or work hardened materials and/or materials that exhibit relatively high shear stress, is that the blade life is not as long as desired and/or the blades do not cut the materials as straight as desired. Current band saw blade designs attempt to overcome these drawbacks by using two distinct methodologies. One approach has been to apply extreme rake angles to traditional tooth/set geometries, without differentiating between “kerf-generating” and “non-kerf-generating” tooth features. Another approach has been to incorporate a “radius” feature on the rake face to capture the chips. Although these methodologies can be moderately effective when the blades are new, and therefore relatively sharp, they have significant drawbacks. The first methodology leads to rapid tool wear due to the use of relatively aggressive, “self-feeding” geometries on the rake faces of kerf-generating teeth. This approach tends to fracture or “chip-out” these teeth in an uncontrolled, unpredictable manner. With the second methodology, on the other hand, the full-contact radius feature allows for an extended tool-chip interface region that leads to increased cutting forces and higher heat generation back into the tool which, in turn, leads to more rapid wear than desired.
It is an object of the present invention to overcome one or more of the above-described drawbacks and/or disadvantages of the prior art.
The present invention is directed to a saw blade, such as a metal-cutting band saw blade or hole saw or hole cutter. The saw blade comprises a cutting edge including a plurality of teeth thereon. A plurality of the teeth include a tip, a clearance surface located on one side of the tip, a rake face located on an opposite side of the tip relative to the clearance surface, a gullet, and a substantially flat, linear, or non-curvilinear projection formed between the rake face and the gullet and projecting outwardly relative to the rake face. The projection is inclined at an acute angle relative to a plane extending between the tips of at least two teeth. The projection defines an inner end adjacent to the rake face and an outer end adjacent to the gullet. The inner end is located at a depth below the tip of at least about 25/1000 inch, and the distance between the inner end and the outer end of the projection in a direction substantially parallel to the plane extending between the tips of at least two teeth is less than about 65/1000 inch.
In some embodiments of the present invention, the projection is inclined at an acute angle relative to the plane extending between the tips of at least two teeth within the range of about 64° to about 79°, and preferably within the range of about 66° to about 70°.
In some embodiments of the present invention, the inner end of the projection is located at a depth below the tip within the range of about 25/1000 inch to about 65/1000 inch, and preferably within the range of about 30/1000 inch to about 55/1000 inch.
In some embodiments of the present invention, the rake face defines a positive rake angle. A rake face defines a positive rake angle when the rake face is inclined inwardly at an angle of greater than 90° relative to a plane extending between the tips of teeth. A rake face defines a “zero degree” rake angle, on the other hand, when the rake face is oriented at 90° relative to a plane extending between the tips of teeth. A positive rake angle is determined based on the extent to which the rake face is inclined inwardly relative to the plane extending between the tips of teeth beyond 90°, e.g., 91° is equal to a 1° positive rake angle, 92° is equal to a 2° positive rake angle, and so on. In the currently preferred embodiments of the present invention, the positive rake angle is preferably within the range of about 10° to about 17°, and more preferably is within the range of about 12° to about 16°.
In some embodiments of the present invention, the distance between the inner end and the outer end of the projection in a direction substantially parallel to the plane extending between the tips of at least two teeth is at least about 5/1000 inch, is preferably at least about 10/1000 inch, is more preferably at least about 15/1000 inch, and is even more preferably at least about 20/1000 inch. In other embodiments of the present invention, the distance between the inner end and the outer end of the projection in a direction substantially parallel to the plane extending between the tips of at least two teeth is within the range of about 5/1000 inch to about 25/1000 inch, and is more preferably, within the range of about 8/1000 inch to about 20/1000 inch.
In some embodiments of the present invention, the plurality of teeth define a repeating set pattern including an unset leading tooth, at least one relatively light-set tooth trailing the unset leading tooth and defining a relatively light set magnitude, and at least one relatively heavy set tooth trailing the unset leading tooth and defining a relatively heavy set magnitude in comparison to the set magnitude of the relatively light set tooth. The relatively heavy set tooth defines a rake angle that is less than the rake angle of at least one of the unset leading tooth and the relatively light set tooth. In some such embodiments, the relatively heavy set tooth defines a rake angle that is less than the rake angle of the unset leading tooth and the relatively light set trailing tooth. In some such embodiments, the relatively heavy set tooth defines a rake angle that is at least about 60% less than each of the rake angle of the unset leading tooth and the rake angle of the relatively light set trailing tooth. In some such embodiments, the relatively heavy set tooth defines a rake angle that is within the range of about 60% to about 80% less than each of the rake angle of the unset leading tooth and the rake angle of the relatively light set trailing tooth (i.e., about 60% to about 80% of about 10° to about 17°, and more preferably, of about 12° to about 16°).
In some embodiments of the present invention, the repeating set pattern includes an unset leading tooth, a relatively light right set trailing tooth, a relatively heavy left set trailing tooth, a relatively heavy right set trailing tooth, and a relatively light left set trailing tooth. In some such embodiments, the unset leading tooth is followed by the light right set trailing tooth, which is followed by the relatively heavy left set trailing tooth, which is followed by the relatively heavy right set trailing tooth, which is followed by the relatively light left set trailing tooth.
In some embodiments of the present invention, the plurality of teeth define a repeating set pattern including an unset leading tooth, at least one relatively light set tooth trailing the unset leading tooth and defining a relatively light set magnitude, and at least one relatively heavy set tooth trailing the unset leading tooth and defining a relatively heavy set magnitude in comparison to the set magnitude of the relatively light set tooth. The relatively heavy set tooth defines a primary clearance angle that is less than the primary clearance angle of the unset leading tooth and the primary clearance angle of the relatively light set trailing tooth. In some such embodiments, the primary clearance angle of the relatively heavy set tooth is within the range of about 0° to about 8°. In some embodiments, the primary clearance surface of the relatively heavy set tooth is shorter than the primary clearance surface of the unset leading tooth and the primary clearance surface of the relatively light set tooth. In some such embodiments, the primary clearance surface of the relatively heavy set tooth defines a length within the range of about 2/1000 inch to about 6/1000 inch.
In accordance with another aspect, the present invention is directed to a metal-cutting saw blade, such as a band saw blade or hole cutter blade, comprising a cutting edge including a plurality of teeth thereon. A plurality of the teeth include a tip, a clearance surface located on one side of the tip, a rake face located on an opposite side of the tip relative to the clearance surface, a gullet, and means projecting outwardly from the rake face between the rake face and the gullet for tangentially contacting and creating curled metal chips and moving them away from the rake face toward the opposite side of the gullet relative to the rake face.
In some embodiments of the present invention, the means for contacting and creating curled metal chips and moving them (i) is inclined at an acute angle relative to a plane extending between the tips of at least two teeth, (ii) defines an inner end adjacent to the rake face and an outer end adjacent to the gullet, (iii) the inner end is located at a depth below the tip of at least about 25/1000 inch, and (iv) the distance between the inner end and the outer end in a direction substantially parallel to the plane extending between the tips of at least two teeth is less than about 65/1000 inch. In some embodiments of the present invention, the means for contacting and creating curled metal chips and moving them is a substantially flat, linear, or non-curvilinear projection.
One advantage of the present invention is that the substantially flat, linear, or non-curvilinear projection or like means allows for the creation of relatively tightly curled metal chips that are projected or moved away from the front edge or rake face of the tooth toward the far or opposite side of the gullet. This redirecting of the forming chip results in an efficient use of available tooth gullet capacity and a reduction in the heat generated at the rake face surface due to the minimized tool/chip contact zone in comparison to prior art metal cutting saw blades. Yet another advantage of the currently preferred embodiments of the present invention is that the depth of the projection, and the length and inclined angle of the projection, are within a geometry window that facilitates formation of relatively tightly curled metal chips without the adverse effects of increased cutting forces at the tooth tip as encountered in prior art saw blades. More specifically, because the substantially flat, linear, or non-curvilinear projection is located at a depth below the tooth tip within the range of about 25/1000 inch to about 65/1000 inch, and preferably within the range of about 30/1000 inch to about 55/1000 inch, and because the distance between the inner end and the outer end of the projection in a direction substantially parallel to the plane extending between the tips of at least two teeth is within the range of about 5/1000 inch to about 25/1000 inch, and more preferably within the range of about 8/1000 inch to about 20/1000 inch, the projection is allowed to form relatively tightly curled metal chips substantially without the adverse effects of increased cutting forces at the tooth tip. Yet another advantage is that the substantially flat, linear, or non-curvilinear projection tangentially contacts the chips to minimize the surface area of the projection in contact with the chips and the resulting cutting forces imparted on the tooth, while nevertheless forming relatively tightly curled chips and projecting or moving them toward the opposite side of the gullet.
Yet another advantage of some currently preferred embodiments of the present invention is that they incorporate multi-level set geometries for both increasing blade life and providing straighter cuts in comparison to prior art saw blades. It has been discovered that a primary driver for overall cutting forces is the relative cutting efficiency of the unset and relatively light set teeth. Accordingly, in the currently preferred embodiments of the present invention, these teeth define relatively aggressive rake angles along with the chip-controlling projection described above to penetrate the sawn material with a relatively low resistance. It also has been discovered that a key to relatively long blade life with relatively straight cuts resides in the relatively heavy set teeth. In some embodiments of the present invention, the relatively heavy set teeth define less aggressive rake angles, preferably within the range of about 60% to about 80% of the rake angles of the unset and relatively light set teeth. The relatively less aggressive rake angles allow the heavy set teeth to maintain substantially straight cuts due to the relatively slow or controlled wear of such teeth, while nevertheless maintaining relatively low cutting forces and tightly controlled chips due to the geometries of the unset and light set teeth, as described above.
Yet another advantage of some embodiments of the present invention is that the heavy set teeth define relatively shallow primary clearance angles in comparison to the unset and relatively light set teeth, such as clearance angles within the range of about 0° to about 8°, and define primary clearance surface lengths within the range of about 2/1000 inch to about 6/1000 inch, to thereby impart a relatively stable, “pre-worn” tooth geometry to the relatively heavy set teeth. As a result, the relatively heavy set teeth wear in a relatively even or consistent manner by avoiding the relatively chaotic tooth wear that can be inherent in saw teeth with sharper tips (e.g., with more aggressive primary clearance angles and/or longer primary clearance surfaces), while nevertheless maintaining relatively low cutting forces and tightly controlled chips due to the geometries of the unset and light set teeth, as described above.
Accordingly, the saw blades of the present invention, such as metal-cutting band saw blades, provide significant user benefits when cutting difficult-to-cut materials, such as tool steels, stainless steels, nickel-based alloys, or other hardened or work hardened materials and/or materials that exhibit relatively high shear stress. Yet another advantage of the saw blades of the present invention is that they allow such materials to be cut with increased blade life and straighter cuts in comparison to prior art saw blades.
Other objects and advantages of the present invention, and/or of the currently preferred embodiments thereof, will become more readily apparent in view of the following detailed description of the currently preferred embodiments and accompanying drawings.
In
Referring to
Each linear projection 30 defines an inner end 31 substantially contiguous to the base of the rake face 24, and an outer end 33 at the entry to the gullet 28. A junction radius RP is formed between the inner end 31 of the linear projection 30 and the base of the rake face 24. In the illustrated embodiment, the junction radius RP is within the range of about 5/1000 inch to about 15/1000 inch. Because of the positive rake, as described further below, and the very small size of the radius RP, it typically should not contact the chips flowing off the rake face. Rather, the chips tangentially contact the substantially flat, linear, or non-curvilinear surface of the projection 30 as described further below. As can be seen, the linear projection 30 defines a substantially flat, linear, or non-curvilinear surface extending between its inner end 31 and outer end 33 that is inclined at an acute angle “PA” relative to a plane extending between the tips of consecutive unset teeth. In the illustrated embodiments of the present invention, the acute angle “PA” is within the range of about 64° to about 79°, and preferably is within the range of about 66° to about 70°.
Each projection 30 projects forward a distance “P1” in a direction parallel to the plane 13 between its inner end 31 and outer end 33. In the illustrated embodiments of the present invention, P1 is within the range of about 5/1000 to about 25/1000 inch, and is more preferably within the range of about 8/1000 inch to about 20/1000 inch. Accordingly, P1 is at least about 5/1000 inch, and is preferably at least about 10/1000 inch to about 15/1000 inch. As shown in
As shown best in
The substantially flat, linear, or non-curvilinear projection 30 allows for the formation of relatively tightly curled chips that are projected away from the rake face 24 of a respective tooth 18 toward the far or opposite side of the respective gullet 28. This redirecting of the chips results in more efficient use of available gullet capacity. The ranges set forth above, and particularly those for D1, PA and P1, define a geometry window that facilitates the aforementioned tightly curled chips without the adverse effects of increased cutting forces at the tooth tip. The projection 30 also allows for a reduction of the contact zone of the chips with the saw blade surface, resulting in reduction in the heat generated at the rake face surface. Because the linear projection 30 is substantially flat, linear, or non-curvilinear, and because of its inclined angle, length, and location between the base of the positive rake and the inlet to the gullet, it tangentially contacts the chips to thereby minimize the surface area of the projection in contact with the chips and the resulting cutting forces imparted on the tooth, while nevertheless forming relatively tightly curled chips and projecting or moving them toward the opposite side of the gullet 28.
As shown in
S−R(l)−L(h)−R(h)−L(l),
The tip 20 of each unset tooth (S) is at the nominal tip tooth plane 13, the tip 20 of each light set tooth (R(l) or L(l)) is at or defines a relatively slight tooth tip drop below the nominal tooth tip plane 13, and each heavy set tooth (R(h) and L(h)) defines a maximum tooth tip drop below the nominal tooth tip plane 13. This multi-level set scheme effectively cuts difficult-to-cut materials by creating relatively deep, narrow chips which, in turn, leads to increased blade life and provides straighter cuts in comparison to prior art saw blades.
In
It has been discovered that a primary driver for overall cutting forces is the relative cutting efficiency of the unset (e.g., S) and relatively light set teeth (e.g., R(l) and L(l)). Accordingly, as indicated in connection with the description of
In
Another exemplary band saw blade of the present invention incorporates a repeating seven tooth, two-tier set pattern as follows:
S−R(h)−L(h)−R(l)−L(l)−R(h)−L(h),
In the same manner as indicated above, S is the unset leading tooth, R(h) is the second tooth set to the right at a relatively heavy set magnitude, L(h) is the third tooth set to the left at a relatively heavy set magnitude, R(l) is the fourth tooth set to the right at a relatively light set magnitude, L(l) is the fifth tooth set to the left at a relatively light set magnitude, R(h) is the sixth tooth set to the right at a relatively heavy set magnitude, and L(h) is the seventh tooth set to the left at a relatively heavy set magnitude. As indicated above, the unset (S) and light set (R(l) and L(l)) teeth define relatively aggressive rake angles RA (i.e., within the range of about 10° to about 17°, and preferably within the range of about 12° to about 16°), whereas the heavy set teeth (R(h) and L(h)) define less aggressive rake angles RA, preferably within the range of about 60% to about 80% of the rake angles RA of the unset (S) and relatively light set teeth (R(l) and L(l)).
Another exemplary band saw blade of the present invention incorporates a ten tooth repeating pitch pattern with a seven/three multi-level set pattern within the pitch pattern, as follows:
S−R(l)−L(m)−R(m)−L(l)−R(h)−L(h)−S−R(h)−L(h)
The S, R(l), L(l), R(h) and L(h) teeth are as described above. The L(m) teeth are set to the left at a medium set magnitude between the set magnitudes of the left light and left heavy set teeth, and the R(m) are set to the right at a medium set magnitude between the set magnitudes of the right light and right heavy set teeth. In the same manner as indicated above, the unset (S), light set (R(l) and L(l)), and medium set (R(m) and L(m)) teeth define relatively aggressive rake angles RA (i.e., within the range of about 10° to about 17°, and preferably within the range of about 12° to about 16°), whereas the heavy set teeth (R(h) and L(h)) define less aggressive rake angles RA, preferably within the range of about 60% to about 80% of the rake angles RA of the unset (S), relatively light set (R(l) and L(l)), and relatively medium set teeth (R(m) and L(m)). This pitch/set pattern facilitates increased chip segmentation which, in turn, leads to reduced cutting forces on the heavy set teeth (R(h) and L(h)).
In an alternative embodiment of the present invention, the relatively heavy set teeth (R(h) and L(h)) define relatively shallow primary clearance angles CA in comparison to the unset (S) and relatively light set teeth (R(l) and L(l), and if applicable, the relatively medium set teeth (R(m) and L(m)). In the currently preferred embodiments, the clearance angles CA of the relatively heavy set teeth are within the range of about 0° to about 8°. In addition, the relatively heavy set teeth (R(h) and L(h)) have primary clearance surfaces 22 that define lengths (i.e., the distance between the tip 20 and the junction between the primary clearance surface 22 and secondary clearance surface 32) within the range of about 2/1000 inch to about 6/1000 inch. These relatively shall clearances on the heavy set teeth impart a stable, “pre-worn” tooth geometry to these teeth. The unset teeth and relatively light set teeth, on the other hand, define geometries as described above in connection with the embodiment of
As may be recognized by those of ordinary skill in the pertinent art based on the teachings herein, numerous changes and modification may be made to the above-described and other embodiments of the present invention without departing from its scope as defined in the appended claims. For example, the geometry of the teeth may take any of numerous different shapes and/or dimensions other than those disclosed herein. Similarly, the teeth may take any of numerous different sets, pitches, set patterns, and/or pitch patterns other than as disclosed herein. In addition, the present invention is not limited to band saw blades, but may be incorporated in, for example, hole saws or hole cutters. Still further, the saw blades of the present invention may be made of any of numerous different materials or combinations of materials, such as bi-metal or carbide tipped, or other saw blade saw materials that are currently known, or that later become known. Accordingly, this detailed description of embodiments is to be taken in an illustrative as opposed to a limiting sense.
| Number | Name | Date | Kind |
|---|---|---|---|
| 603128 | Clemson | Apr 1898 | A |
| 820969 | Grelck | May 1906 | A |
| 2071618 | Ferrari et al. | Feb 1937 | A |
| 2270776 | Thornton | Jan 1942 | A |
| 2624381 | Von der Werth | Jan 1953 | A |
| 2637355 | Chapin | May 1953 | A |
| 2714317 | Drake | Aug 1955 | A |
| 3866504 | Claesson et al. | Feb 1975 | A |
| 3990334 | Mellgren | Nov 1976 | A |
| 4031793 | Miaskoff | Jun 1977 | A |
| 4043404 | Sorlie et al. | Aug 1977 | A |
| 4179967 | Clark | Dec 1979 | A |
| RE31433 | Clark | Nov 1983 | E |
| 4557172 | Yoneda | Dec 1985 | A |
| 4603613 | Wilson | Aug 1986 | A |
| 4867026 | Henning et al. | Sep 1989 | A |
| 4958546 | Yoshida et al. | Sep 1990 | A |
| 5016356 | Trench | May 1991 | A |
| 5331876 | Hayden, Sr. | Jul 1994 | A |
| 5410935 | Holston et al. | May 1995 | A |
| 5425296 | Kullmann et al. | Jun 1995 | A |
| 5440960 | Sadahiro | Aug 1995 | A |
| 5603252 | Hayden, Sr. | Feb 1997 | A |
| 5606900 | Stoddard | Mar 1997 | A |
| 5642766 | MacCauley, III | Jul 1997 | A |
| 5826477 | Brewer, Sr. | Oct 1998 | A |
| 5832803 | Hayden, Sr. | Nov 1998 | A |
| 5868058 | Senegas | Feb 1999 | A |
| 6003422 | Holston | Dec 1999 | A |
| D427865 | Mills, Jr. | Jul 2000 | S |
| 6152815 | Meerdink et al. | Nov 2000 | A |
| 6158324 | Kullmann et al. | Dec 2000 | A |
| 6167792 | Korb et al. | Jan 2001 | B1 |
| D439666 | Ventura | Mar 2001 | S |
| 6220139 | Kobayashi et al. | Apr 2001 | B1 |
| 6220140 | Hellebergh | Apr 2001 | B1 |
| 6244152 | Di Nicolantonio | Jun 2001 | B1 |
| 6314854 | Fritz et al. | Nov 2001 | B1 |
| 6439094 | Yoneda et al. | Aug 2002 | B1 |
| 6505537 | Vöge | Jan 2003 | B1 |
| 6520722 | Hopper et al. | Feb 2003 | B2 |
| 6532852 | Tsujimoto et al. | Mar 2003 | B1 |
| 6588992 | Rudolph | Jul 2003 | B2 |
| 6598509 | Cook et al. | Jul 2003 | B2 |
| 6601495 | Cranna | Aug 2003 | B2 |
| 6834573 | Nakahara | Dec 2004 | B1 |
| 7017465 | Dion et al. | Mar 2006 | B2 |
| 7036415 | Tsujimoto | May 2006 | B2 |
| 7036417 | Alton | May 2006 | B2 |
| 7077041 | Kunkel et al. | Jul 2006 | B2 |
| 7121180 | Shimofurutani | Oct 2006 | B2 |
| 7127979 | Kocher et al. | Oct 2006 | B2 |
| 7150215 | Krehel | Dec 2006 | B2 |
| 7163366 | Chen | Jan 2007 | B2 |
| 7178441 | Hellbergh | Feb 2007 | B2 |
| 7216942 | Yasutake et al. | May 2007 | B2 |
| 7225714 | Rompel et al. | Jun 2007 | B2 |
| D555444 | Ammann | Nov 2007 | S |
| 7334511 | Hesselberg et al. | Feb 2008 | B2 |
| D575808 | Zeiler et al. | Aug 2008 | S |
| 7451678 | Dion et al. | Nov 2008 | B2 |
| 7488146 | Brunson | Feb 2009 | B2 |
| 7517179 | Miller et al. | Apr 2009 | B2 |
| 7559726 | Beach | Jul 2009 | B1 |
| 7568416 | Tsujimoto | Aug 2009 | B2 |
| 7578672 | Sheikh et al. | Aug 2009 | B2 |
| D605672 | Allen et al. | Dec 2009 | S |
| 7625160 | Zeiler et al. | Dec 2009 | B2 |
| 7661347 | Nagano et al. | Feb 2010 | B2 |
| 7832320 | Earle et al. | Nov 2010 | B2 |
| 7913601 | Petts et al. | Mar 2011 | B2 |
| 8210081 | Elliston et al. | Jul 2012 | B2 |
| 8621972 | Nagano | Jan 2014 | B2 |
| 8695470 | Kullmann et al. | Apr 2014 | B2 |
| 20020124707 | Izard | Sep 2002 | A1 |
| 20040035282 | Tsujimoto | Feb 2004 | A1 |
| 20040255740 | Troyer | Dec 2004 | A1 |
| 20060065098 | Cranna | Mar 2006 | A1 |
| 20090274923 | Hall et al. | Nov 2009 | A1 |
| 20110265627 | Kwanka | Nov 2011 | A1 |
| Number | Date | Country |
|---|---|---|
| 100 30 168 | Jan 2001 | DE |
| 10253711 | Jun 2004 | DE |
| 10 2006 015 278 | Oct 2007 | DE |
| 1 586 401 | Oct 2005 | EP |
| 2352223 | Oct 2007 | ES |
| 2 354 480 | Mar 2001 | GB |
| 52026679 | Feb 1977 | JP |
| 63-256309 | Oct 1988 | JP |
| H01-011708 | Jan 1989 | JP |
| S6411708 | Jan 1989 | JP |
| 6000-716 | Jan 1994 | JP |
| 6000-717 | Jan 1994 | JP |
| 2000-343325 | Dec 2000 | JP |
| 2001-9634 | Jan 2001 | JP |
| 2001-62629 | Mar 2001 | JP |
| 2004-504170 | Feb 2004 | JP |
| WO 9932251 | Jul 1999 | WO |
| WO0206020 | Jan 2002 | WO |
| WO 2006042929 | Apr 2006 | WO |
| WO 2007098276 | Aug 2007 | WO |
| WO 2008092239 | Aug 2008 | WO |
| WO 2009073030 | Jun 2009 | WO |
| WO 2010148471 | Dec 2010 | WO |
| WO 2011002411 | Jan 2011 | WO |
| Entry |
|---|
| “Frost Tooth Gullet Design”, Armstrong Saw Engineer, Jul.-Dec. 1991, No. 139, Armstrong Manufacturing Co., Portland, Oregon. |
| Number | Date | Country | |
|---|---|---|---|
| 20130149059 A1 | Jun 2013 | US |
