TECHNICAL FIELD

Example embodiments generally relate to hand held power equipment and, more particularly, relate to blade improvements for a circular saw.

BACKGROUND

Circular saws are commonly used in both commercial and private settings to cut lumber or perform other rigorous cutting operations. Typically employed in a construction setting, circular saws are most often powered by an electric motor that rotates a circular saw blade at relatively high speeds. The blade includes cutting teeth that engage lumber or another medium in order to cut the medium as the teeth are passed over a surface of the medium at high speed.

Given that circular saws may be employed to cut media of various types and to achieve cuts of various degrees of smoothness, the tooth pattern of the circular saw blade can be different for different applications. Circular saw blades that are designed to cut faster typically also produce a rougher cut. These blades commonly have less teeth and larger gullets between each tooth. A few examples of this type of blade include “rip-cut” blades and “framing” blades. On the other hand, circular saw blades that are designed to produce a smoother cut will typically have more teeth with smaller gullets between each tooth. Some examples of this type of blade include “crosscut” and “finishing” blades. Although circular saw blades can range in diameter from 5.5 inches to 24 inches, it is common for both framing and finishing blades to have a diameter of 7 - inches since this size blends the quickness of a small blade with sufficient capacity or cutting depth.

Creating a framing blade with certain qualities that may be uncharacteristic of typical framing blades may allow for a more favorable overall cutting experience than a typical framing blade could produce. However, the number of teeth is not the only concern or point of possible improvement in relation to circular saw blade design. As such, it may be desirable to explore a number of different circular saw blade design improvements that could be employed alone or together to improve overall circular saw performance. BRIEF SUMMARY OF SOME EXAMPLES In an example embodiment, a circular saw blade may be provided. The circular saw blade may include a body defined by a planar metallic plate, an arbor disposed at a center of the body defining an axis of rotation for the blade, a plurality of projections extending away from a perimeter of the body where the projections each have a leading edge and a trailing edge, and a plurality of teeth disposed at the projections such that one tooth is located at the leading edge of each of the projections. The teeth may be provided in a three-tooth repeating pattern in which every third tooth extends farther away from the body than other teeth of the three- tooth pattern.

In another example embodiment, a circular saw blade may be provided in which the blade includes a body defined by a planar metallic plate, an arbor disposed at a center of the body defining an axis of rotation for the blade, a plurality of projections extending away from a perimeter of the body where the projections each have a leading edge and a trailing edge, and a plurality of teeth disposed at the projections. One tooth may be located at the leading edge of each of the projections. A first tooth of a first projection may extend a first distance away from the body, and a second tooth, adjacent the first tooth, may extend a second distance away from the body. The second distance may be less than the first distance. The first tooth may be made of a different material than the second tooth.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

Having thus described some example embodiments in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein: FIG. 1 illustrates a side view of a circular saw according to an example embodiment;

FIG. 2 illustrates a side view of a saw blade in accordance with an example embodiment;

FIG. 3 illustrates a portion of a front view of a three tooth section of the blade in accordance with an example embodiment;

FIG. 4 illustrates a portion of a front view of a three tooth section of the blade in accordance with an example embodiment;

FIG. 5 illustrates a portion of a side view of the blade highlighting a raised tooth pattern in accordance with an example embodiment;

DETAILED DESCRIPTION

Some example embodiments now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all example embodiments are shown. Indeed, the examples described and pictured herein should not be construed as being limiting as to the scope, applicability or configuration of the present disclosure. Rather, these example embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like reference numerals refer to like elements throughout. Furthermore, as used herein, the term “or” is to be interpreted as a logical operator that results in true whenever one or more of its operands are true. As used herein, operable coupling should be understood to relate to direct or indirect connection that, in either case, enables functional interconnection of components that are operably coupled to each other.

Some example embodiments may provide for a circular saw blade constructed from steel and having projections disposed at the periphery of the blade. The projections include some teeth made from carbide and some other teeth made from high-speed steel (HSS). The teeth are brazened onto the projections of the saw blade. HSS as a material can withstand higher temperatures than carbide before compromising on its hardness. Therefore, the mixed use of carbide teeth and HSS teeth allows for faster cutting than a blade consisting solely of carbide teeth. Additionally, teeth made from HSS may extend further out from the blade’s edge than teeth made from carbide. This allows the HSS teeth to come into contact with potential debris in the cutting medium before the teeth made from carbide. Therefore, the HSS teeth enhance the overall durability of the saw blade by reducing the impact on the carbide teeth. Other improvements may also be possible, and the improvements can be made completely independent of each other, or in combination with each other in any desirable configuration. Accordingly, the operability and utility of the circular saw blade may be enhanced or otherwise facilitated while strengthening the saw blade without sacrificing the quality of the cut.

FIG. 1 illustrates side view of a circular saw 100 according to an example embodiment. As shown in FIG. 1, the circular saw 100 may include a handle 110 that an operator (not shown) may utilize to operate the circular saw 100. An operator may securely grasp the circular saw 100 by the handle 110 in order to control the circular saw 100 while making a cut. The circular saw 100 may be operably coupled to a power source 120. In some embodiments, the power source 120 may be a source of electricity that provides power to a power unit or motor (e.g. mains power or a battery pack). In some embodiments, the power unit may be an electric motor which may directly power the working assembly of the circular saw 100.

The handle 110 may be operably coupled to an upper guard 130, and the upper guard may be operably coupled to a shoe 140. The upper guard 130 and the shoe 140 may serve to improve the overall cutting experience for the operator of the circular saw 100. The shoe 140 may provide support for the circular saw 100 when the circular saw 100 is in use. The shoe 140 may also help ensure that the circular saw 100 remains in proper alignment throughout the duration of the cut, and may also serve as a guide for an operator to follow to achieve the straightest possible cut. When the circular saw 100 is in use, the shoe 140 may be in a fixed orientation and may also slide along a surface of a medium that is being cut. The shoe 140 may also be fixed at an arbitrary angle defined by the operator in order to perform angled cuts. The upper guard 130 may form a safety barrier between the operator and a blade 150 that may be capable of rotating at high speeds. The upper guard 130 may serve to keep the operator away from the blade 150, as well as protect the operator from the potential of debris being projected at high speeds away from the blade 150.

There may also be a retracting lower blade guard 160 operably coupled to the circular saw 100. The retracting lower blade guard 160 may be configured to retract into the upper guard 130, when the circular saw 100 is in use, in the direction of the arrow shown in FIG. 1. The retracting lower blade guard 160 may be pushed into a retracted state by the medium being cut as the circular saw 100 moves through the medium. The retracting lower blade guard 160 may be spring loaded or biased to completely cover the portion of the blade 150 that extends below the shoe 140 when the circular saw 100 is not in use. The blade 150 may be operably coupled to the circular saw 100 and the power unit at an arbor hole 170 at the center of the blade 150. The center of the arbor hole 170 may also contain a center of rotation 180 of the blade 150. Responsive to operation of the power unit, the blade 150 may rotate about the center of rotation 180 in order to enable the circular saw 100 to cut lumber or other materials. The blade 150 and the arbor hole 170 may form the working assembly of the circular saw 100. As such, the power unit may be operably coupled to the working assembly to rotate the blade 150 about the center of rotation 180.

The handle 110 may include a trigger 115 to facilitate operation of the power unit when the trigger 115 is actuated. In this regard, for example, when the trigger 115 is actuated (e.g., depressed), the rotating forces generated by the power unit may be coupled to the blade 150 directly. The term "trigger," as used herein, should be understood to represent any actuator that is capable of being operated by a hand or finger of the user. Thus, the trigger 115 may represent a button, switch, or other such component that can be actuated by a hand or portion thereof.

As can be appreciated from the description above, actuation of the trigger 115 may initiate rotation of the blade 150 about the center of rotation 170. Further, in some embodiments, the power unit may be an electric motor which may power the working assembly of the circular saw 100. In such embodiments, the electric motor may be directly coupled to the saw blade 150. In this regard, the circular saw 100 may not use extra gears or clutches to translate power from the electric motor to the blade 150. Thus, depressing the trigger 115 may directly engage the power unit’s full power to rotating the blade 150, and releasing the trigger 115 may directly disengage all power from rotating the blade 150.

In some embodiments, the circular saw 100 may have a single-speed power unit or electric motor. Thus, an important factor in determining the relative quickness with which a cut can be completed is how the blade 150 to constructed or structured. Therefore, it may be desirable to provide various improvements to the structural arrangement of the blade 150 to improve the functionality of the blade 150 for different use cases. Various example embodiments will now be described in reference to FIGS. 2-5, which illustrate some of these example embodiments.

In this regard, FIG. 2 illustrates a side view of a blade 200 in accordance with an example embodiment. In some embodiments, a body 210 of the blade 200 may be formed from stamping or cutting the outline of the blade 200 out of steel or another sufficiently rigid and durable material. The body 210 of the blade 200 may comprise an almost entirely solid sheet of planar material excluding an arbor hole 220. In some embodiments, the body 210 may comprise slots cut through the body 210 disposed around the arbor hole 220 that do not come into contact with a periphery of the blade 200. The blade 200 may also include projections 230. The projections 230 may comprise the same material as the body 210, and may also be formed in the same stamping or cutting process that forms the body 210. In this regard, the projections 230 may be solid extensions of the body 210. At its greatest length, a diameter of the blade 200 may be 7 - inches measured between diametrically opposite projections 230.

Additionally, projections 230 may have a leading edge and a trailing edge. The leading edges of the projections 230 are the first part of the projections 230 that will contact the medium being cut as the blade 200 rotates. The trailing edges, on the other hand, are the last part of the projections 230 that will pass the medium being cut as the blade 200 rotates. The blade 200 may also include a gullet 240 formed between the leading and trailing edges of all consecutive projections 230. The gullet 240 may assist with removing debris produced during a cutting operation to prevent the blade 200 from getting damaged from a buildup of debris. Additionally, the gullets 240 may prevent overheating of the blade 200 which, in turn, minimizes both the potential for the blade 200 to warp, and the potential to initiate other damage. In an example embodiment, the projections 230 may include teeth 250. Teeth 250 may be brazened, welded, or affixed by other means, onto the leading edge of the projections 230. Teeth 250 may provide the point of contact between the blade 200 and the medium that is to be cut. As such, teeth 250 may be subject to the most impact out of all the components of the blade 200. A blade 200 may comprise teeth 250 made from carbide, high-speed steel (HSS), and/or a mixture of some teeth 250 made from carbide and some made from HSS. Teeth 250 may also be implemented into the blade in a plurality of different types and different patterns. In some embodiments, the blade 200 may include a 3 -tooth pattern, which may help the blade 200 achieve better cutting results. This pattern will be discussed in greater detail below. Circular saw blades may come in a plurality of shapes and sizes for different purposes. The blade 200 may either be a finishing blade or a framing blade. Finishing blades tend to have more projections 230 than framing blades, and for that reason, they may also cut slower than framing blades. Framing blades typically have 24 projections 230 and finishing blades typically have 48 projections 230. However, as a result of having more projections 230, finishing blades produce a cleaner cut than do framing blades. In the example shown in FIG.

2, the blade 200 may have a diameter of 7- inches and have a total of 27 projections 230. The increase in number of projections 230 from the common number of 24 provides a number of benefits, which will be discussed in greater detail below. In some embodiments, the size of the gullets 240 may depend on the number and size of projections 230 that are present on the blade 200. The gullets 240 may be larger or smaller than shown in FIG. 2 depending on the length of material defined between the leading and trailing edges of the blade 200 for a given number of projections 230. The size of the gullets 240 may also largely depend on the intended use of the blade 200. In this regard, a framing blade may have larger gullets 240 than a finishing blade.

The pattern with which the teeth 250 are affixed to the projections 230 may also impact the performance of the blade 200. Commonly, circular saw blades may comprise one of a flat top grind pattern, an alternate top bevel pattern, or an alternate top bevel with raker pattern. This list of teeth 250 patterns is not meant to be exhaustive, but is merely intended to provide a few common examples of circular saw teeth 250 patterns. A flat top grind pattern may not produce a clean cut, and as such, may be commonly used on framing blades. A flat top grind pattern may comprise squared off teeth 250 that are relatively flat and very durable. Alternatively, an alternate top bevel pattern may be more commonly found on finishing blades due to its ability to produce a cleaner cut. This pattern may typically comprise teeth 250 that include a beveled top face of the tooth 250. The direction of the bevel may change or alternate with each consecutive tooth 250. The alternate top bevel with raker pattern may closely resemble the alternate top bevel pattern, but may also include a raker tooth that is not beveled in either direction but rather resembles a flat top grind tooth. The raker tooth may serve to center the blade 200 in the kerf formed by operation of the blade 200 in the media being cut.

FIG. 3 illustrates a portion of a front view of a saw blade 300 with teeth (320, 340, and 350) affixed to the projections 330 in accordance with an example embodiment. In this embodiment, the pattern may resemble a 3 tooth flat top grind pattern but there may be several key improvements over common flat top grind patterns. The three tooth pattern of FIG. 3 may be repeated nine times about a peripheral edge of the blade 300 for a total of 27 teeth on a 7 1/4 inch blade. A first tooth 320 and a second tooth 340 may not extend as far away from the body 310 as a raker tooth 350 does. In some embodiments, the first tooth 320 and the second tooth 340 may be positioned lower on their respective projections 330 than the raker tooth 350. In some embodiments, the raker tooth 350 may be positioned at the same height on the projection 330 yet have a higher profile (RTH) than the first tooth 320 ( TH) or the second tooth 340 (TH). In this regard, the raker tooth 350 may still extend further away from the body 310 than the first tooth 320 or the second tooth 340. The raker tooth 350 extending further out may allow the blade 300 to produce a straighter cut by providing the blade 300 with more opportunities to center itself in the kerf formed in the cutting medium with each rotation of the blade 300 than a 24 tooth blade. In this regard, one extra centering operation is performed for every full revolution of the blade 300. The additional centering operation tends to improve the straightness of the cut. However, in some alternative embodiments, the first tooth 320 or the second tooth 340 may extend further away from the body 310 than the raker tooth 350.

In an example embodiment, the raker tooth 350 may comprise HSS while the first tooth 320 and the second tooth 340 may each comprise carbide. In some embodiments, it may be helpful to form the raker tooth 350 from a material harder than carbide because the raker tooth 350 may be the first part of the blade 300 that makes contact with nails or other objects embedded in the cutting medium. In this regard, since the raker tooth 350 (in this example) has the higher profile (RTH), the raker tooth 350 is first to contact harder objects that may be embedded in the cutting medium. Meanwhile, the raker tooth 350 being made from HSS makes the raker tooth 350 harder than the first tooth 320 and the second tooth 340. Therefore, the raker tooth 350 may be better suited to take the impact of any hard objects or inconsistencies in the cutting medium. In this regard, the raker tooth 350 may be subject to more impact than the first tooth 320 and the second tooth 340, and may correspondingly be made of a stronger material to enable the raker tooth 350 to handle such impact. In some embodiments, since the blade 300 may include 27 total teeth (instead of the typical 24), and since a plurality of raker teeth 350 (in this case 1/3 of them, although it could be 1/2 or another ratio) are made of HSS and therefore stronger material, each raker tooth 350 may not only be designed to handle greater impact, but may advantageously handle less impact per revolution of the blade 300 since there is one extra raker tooth 350 above the normal amount. Thus, the amount of impact that each tooth (320, 340 and 350) takes per full rotation of the blade 300 may be drastically reduced generally, but the amount specifically felt by each raker tooth 350 is also reduced. In this regard, with less impact per tooth (320, 340 and 350) the raker teeth 350 may improve the overall durability and/or longevity of the blade 300. Additionally, teeth 320, 340 and 350 may be wider than the body 310 of the blade 300 in an effort to minimize the amount of material that sticks to the body 310 during cutting. In this regard, the body 310 may have a thickness BT which may be less than the thickness TT of the teeth (320, 340 and 350).

In accordance with this example embodiment, the raker tooth 350 may be more adequately equipped to cut through debris that may be embedded in the cutting medium. In some cases, the debris may comprise nails or other inconsistencies in the lumber or material being cut. In some embodiments, the 3 tooth pattern shown in FIG. 3 may be repeated to a total of 27 projections 330 around the blade 300. In this regard, this configuration may comprise more projections 330 than a standard framing blade, which may commonly comprise 24 projections 330. In some embodiments, the blade 300 may have 27 projections 330 with a distribution of 0.593 projections 330 per inch (measured around the circumference of the blade 300), whereas a typical framing blade may have 24 projections 330 with a distribution of 0.527 projections 330 per inch (again measured around the circumference of the blade 300). Due to the increased number of total projections 330, and a higher number of raker teeth 350, the blade 300 may have greater durability, produce straighter cuts, and have a greater ability to cut through media of various types and possibly also including embedded objects therein. In some embodiments, it may be helpful to remain close to the typical number of projections 330 of a common framing blade to offer the above improvements without compromising on the speed of the cut. Additionally, HSS may cost more from a production standpoint. In this regard, implementing HSS in patterns with the more cost efficient carbide may be helpful in balancing the cost of the blade 300 with the performance of the blade 300. As mentioned above, finishing blades typically have more projections 330 than framing blades (i.e., twice as many), which allows for cleaner finishes on cuts. Accordingly, having a blade 300 that comprises 27 projections 330 as opposed to 24 projections 330, may allow for a better quality finish from the blade 300, without compromising a great deal in other aspects of the blade 300 as discussed above. In other words, the blade having 27 projections 330 may blend some desirable traits of both framing blades and finishing blades.

FIG. 4 illustrates a portion of a front view of a saw blade 400 with teeth (420, 440, and 450) affixed to the projections 430 in accordance with an example embodiment. In this embodiment, the tooth pattern may resemble a 3 tooth alternate top bevel with raker pattern, but again, there may be several key improvements over common alternate top bevel with raker patterns. In some embodiments, the first tooth 420 may have a top face 425 that may be cut at a bevel. The second tooth 440 may also have a top face 445 that may be cut at a bevel, but in the opposite direction. Alternating the direction of the bevel on the first tooth 420 and the second tooth 440 may enhance the quality of the cut by enabling each alternating tooth 430 to cut a different corner of the kerf of the blade 400. A first tooth 420 and a second tooth 440 may not extend as far away from the body 410 as a raker tooth 450 does. In some embodiments, the first tooth 420 and the second tooth 440 may be positioned lower on their respective projections 430 than the raker tooth 450. In some embodiments, the raker tooth 450 may be positioned at the same height on the projection 430 yet have a higher profile than the first tooth 420 or the second tooth 440. In this regard, the raker tooth 450 may still extend further away from the body 410 than the first tooth 420 or the second tooth 440. The raker tooth 450 extending further out may allow the blade 400 to produce a straighter cut by providing the blade 400 with more opportunities to center itself in the cutting medium with each rotation of the blade 400. However, in some further embodiments, the first tooth 420 or the second tooth 440 may extend further away from the body 410 than the raker tooth 450.

In an example embodiment, the raker tooth 450 may comprise HSS while the first tooth 420 and the second tooth 440 may each comprise carbide. In some embodiments, it is helpful that the raker tooth 450 comprises a material harder than carbide because the raker tooth 450 may be the first part of the blade 400 that makes contact with nails or other objects embedded in the cutting medium. Therefore, the raker tooth 450 may be better suited to take the impact of any debris or inconsistencies in the cutting medium if the raker tooth 450 were to comprise a harder material, such as HSS. In this regard, the raker tooth 450 may be subject to more impact than the first tooth 420 and the second tooth 440. In some embodiments, since the blade 400 may include a plurality of raker teeth 450, of which, each may be designed to handle greater impact, the amount of impact that each tooth (420, 440 and 450) takes per full rotation of the blade 400 may be drastically reduced. In this regard, with less impact per tooth (420, 440 and 450) the raker teeth 450 may improve the overall durability and/or longevity of the blade 400. Additionally, teeth 420, 440 and 450 may be wider than the body 410 of the blade 400 in an effort to minimize the amount of material that sticks to the body 410 during cutting.

In accordance with this example embodiment, the raker tooth 450 may be more adequately equipped to cut through debris that may be embedded in the cutting medium. In some cases, the debris may comprise nails or other inconsistencies in the lumber or material being cut. In some embodiments, the 3 tooth pattern shown in FIG. 4 may be repeated to a total of 27 projections 430 around the blade 400. In this regard, this configuration may comprise more projections 430 than a standard framing blade, which may commonly comprise 24 projections 430. In some embodiments, the blade 400 may have 27 projections 430 with a distribution of 0.593 projections 430 (or teeth) per inch, whereas a typical framing blade may have 24 projections 330 with a distribution of 0.527 projections 430 (or teeth) per inch. Due to the increased number of total projections 430, and a higher number of raker teeth 450, the blade 400 may have greater durability, produce straighter cuts, and a greater ability to cut through debris. In some embodiments, it may be helpful to remain close to the typical number of projections 430 of a common framing blade to offer the above improvements without compromising on the speed of the cut. Additionally, HSS may cost more from a production standpoint. In this regard, implementing HSS in patterns with the more cost efficient carbide may be helpful in balancing the cost of the blade 400 with the performance of the blade 400. As mentioned above, finishing blades typically have more projections 430 than framing blades, which allows for cleaner finishes on cuts. Accordingly, having a blade 400 that comprises 27 projections 430 as opposed to 24 projections 430, may allow for a better quality finish from the blade 400, without compromising a great deal in other aspects of the blade 400 as discussed above. In other words, the blade having 27 projections 430 may blend some desirable traits of both framing blades and finishing blades.

FIG. 5 illustrates a portion of a side view of the blade 500 highlighting the raised tooth pattern according to an example embodiment. In accordance with the example embodiments described herein, FIG. 5 illustrates more precise geometry in relation to the patterns described above. In such embodiments, the first tooth 510 may extend to a height (A) above an imaginary reference curve 540 defined by connecting the bottoms of gullets 550. The second tooth 520 and the third tooth 530 may each extend to a height (B) above the reference curve 540, where height (B) may be less than height (A). The pattern depicted in FIG. 5 may then be repeated until the periphery of the blade 500 comprises a full amount of teeth (510, 520 and 530).

FIG. 6 illustrates a portion of a side view of the blade 600 highlighting projections (610 and 620) according to an example embodiment. In accordance with the example embodiments described herein, FIG. 6 illustrates more precise geometry in relation to the patterns described above. In some embodiments, a pattern may comprise 2 teeth (650 and 660), in which a first projection 610 may have a first tooth 650 that may extend to height (C) above an imaginary reference curve 630 defined by connecting the bottoms of gullets 640. A second projection 620 may comprise a second tooth 660 that may extend to height (D) above the imaginary reference curve 630. The height (C) may be greater than the height (D) by greater than about 0.5 mm in some cases. However, differences as large as 1 mm may be present in some cases. The first tooth 650 and the second tooth 660 may comprise different materials as well. In some embodiments the first tooth 650 may be made from carbide. In some embodiments, the second tooth 660 may be made from HSS. The pattern depicted in FIG. 6 may then be repeated until the periphery of the blade 600 comprises a full amount of teeth (650 and 660). In an example embodiment, a circular saw blade may be provided. The circular saw blade may include a body defined by a planar metallic plate, an arbor disposed at a center of the body defining an axis of rotation for the blade, a plurality of projections extending away from a perimeter of the body, the projections each having a leading edge and a trailing edge, and a plurality of teeth disposed at the projections such that one tooth is located at the leading edge of each of the projections. The teeth may be provided in a three-tooth repeating pattern in which every third tooth extends farther away from the body than other teeth of the three-tooth pattern. Alternatively or additionally, the blade may be designed such that one tooth may be located at the leading edge of each of the projections. A first tooth of a first projection may extend a first distance away from the body, and a second tooth, adjacent the first tooth, may extend a second distance away from the body. The second distance may be less than the first distance. The first tooth may be made of a different material than the second tooth.

The blade of some embodiments may include additional features, modifications, augmentations and/or the like to achieve further objectives or enhance performance of the blade. The additional features, modifications, augmentations and/or the like may be added in any combination with each other. Below is a list of various additional features, modifications, and augmentations that can each be added individually or in any combination with each other. For example, every third tooth may be made of a different material than the other teeth of the three-tooth pattern. In an example embodiment, the every third tooth is made of high-speed steel (HSS), and the other teeth are made of carbide. In some cases, a diameter of the blade may be about 7 1/4 inches. In an example embodiment, a number of teeth per inch disposed at the perimeter of the body may be greater than 0.55 (e.g., 0.593). In some cases, the every third tooth may be aligned with a plane of the body, and adjacent ones of the other teeth are bevel cut in opposite directions. In an example embodiment, a total of twenty-seven projections and twenty-seven teeth may be disposed at the perimeter of the body. In some cases, the height difference between teeth may be at least about 0.5 mm. In an example embodiment, each of the teeth may have a width that is wider than a width of the body. In some cases, the teeth may be welded or brazed onto the leading edge of respective ones of the twenty-seven projections.

Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, although the foregoing descriptions and the associated drawings describe exemplary embodiments in the context of certain exemplary combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative embodiments without departing from the scope of the appended claims. In this regard, for example, different combinations of elements and/or functions than those explicitly described above are also contemplated as may be set forth in some of the appended claims. In cases where advantages, benefits or solutions to problems are described herein, it should be appreciated that such advantages, benefits and/or solutions may be applicable to some example embodiments, but not necessarily all example embodiments. Thus, any advantages, benefits or solutions described herein should not be thought of as being critical, required or essential to all embodiments or to that which is claimed herein. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.