SAW BLADE WITH SET CUTTING TEETH
20200180054 ยท 2020-06-11
Inventors
- Poinon Sanogo (Enfield, CT, US)
- Asif Elliston (East Longmeadow, MA, US)
- Matthew Christopher Green (Amherst, MA, US)
- Douglas Fosberg (Wilbraham, MA, US)
- Steve Hampton (East Longmeadow, MA, US)
- ASHKAN SHARIFI (Wilbraham, MA, US)
- Joseph T. Novak (East Longmeadow, MA, US)
- Kurt Langheld (Southwick, MA, US)
- William B. Korb (Broad Brook, CT, US)
Cpc classification
B23D61/021
PERFORMING OPERATIONS; TRANSPORTING
B23D61/122
PERFORMING OPERATIONS; TRANSPORTING
B23D61/023
PERFORMING OPERATIONS; TRANSPORTING
International classification
Abstract
A saw blade includes an elongated body extending along a longitudinal axis and having an elongated cutting edge. A first hard metal strip is attached to a first portion of the cutting edge and includes at least one first full hard metal cutting tooth that is set left at a first angle relative to a vertical axis of the body that is generally perpendicular to the longitudinal axis. A second hard metal strip attached to a second portion of the cutting edge and includes a second full hard metal cutting tooth that is set right at a second angle relative the vertical axis.
Claims
1. A saw blade comprising: a body having a cutting end, a first side face, and a second side face; and a hard metal strip having a base portion affixed to the cutting end, at least one first full hard metal cutting tooth attached to the base portion, and at least one second full hard metal cutting tooth attached to the base portion, each cutting tooth having a first side surface and a second side surface, wherein the first side surface of each first cutting tooth defines a first recess in the first cutting tooth, such that each first cutting tooth is set toward the second side face of the body, and wherein the second side surface of each second cutting tooth defines a second recess in the second cutting tooth, such that each second cutting tooth is set toward the first side face of the body.
2. The saw blade of claim 1, wherein each first recess extends into the first side face of the body.
3. The saw blade of claim 2, wherein each second recess extends into the second side face of the body.
4. The saw blade of claim 1, wherein the first side surface of each first cutting tooth is parallel to the first side face of the body.
5. The saw blade of claim 4, wherein the second side surface of each second cutting tooth is parallel to the second side face of the body.
6. The saw blade of claim 5, wherein the second side surface of each first cutting tooth extends at an angle relative to the second side face of the body.
7. The saw blade of claim 6, wherein the first side surface of each second cutting tooth extends at an angle relative to the first side face of the body.
8. The saw blade of claim 1, wherein the hard metal strip further comprises at least one third hard metal tooth attached to the base portion and being free of any recess, such that the third hard metal tooth is unset.
9. The saw blade of claim 8, wherein a first side surface of each third cutting tooth extends at an angle to the first side face of the body and a second side surface of each third cutting tooth extends at an angle to the second side face of the body.
10. The saw blade of claim 1, wherein each first recess is formed by grinding the first side surface of each first tooth after the hard metal strip has been attached to the body.
11. The saw blade of claim 10, wherein each second recess is formed by grinding the second side surface of each second tooth after the hard metal strip has been attached to the body.
12. The saw blade of claim 1, wherein the saw blade is a reciprocating saw blade, a jigsaw blade, or a bandsaw blade, the first cutting tooth is set toward a left side of the body, and the second cutting tooth is set toward a right side of the body.
13. The saw blade of claim 1, wherein the saw blade is an oscillating blade, the first cutting tooth is set toward a top side of the body, and the second cutting tooth is set toward a bottom side of the body.
14. The saw blade of claim 1, wherein saw blade is a holesaw, the first cutting tooth is set toward an inner side of the body, and the second cutting tooth is set toward a bottom side of the body.
15. The saw blade of claim 1, wherein the hard metal strip comprises a first hard metal strip that includes the first cutting tooth and a second hard metal strip that includes the second cutting tooth.
16. A saw blade comprising: a body extending having a first side face, a second side face, and a cutting end; and a first hard metal strip attached to a first portion of the cutting end and including at least one first full hard metal cutting tooth that is set toward the first side face at a first angle relative to the first side face; a second hard metal strip attached to a second portion of the cutting end and including at least one second full hard metal cutting tooth that is set toward the second side face at a second angle relative to the second side face.
17. The saw blade of claim 17, wherein the first hard metal strip comprises a base coupled to the first portion of the cutting end and at least two of the first full hard metal cutting teeth each set toward the first side face at the first angle.
18. The saw blade of claim 17, wherein the second hard metal strip comprises a base coupled to the second portion of the cutting end and at least two of the second full hard metal cutting teeth each set toward the second side face at the second angle.
19. The saw blade of claim 16, wherein a first side surface of the first tooth is formed to be angled relative to the first side face of the body and a second side surface of the second tooth is formed to be angled relative to the second side face of the body.
20. The saw blade of claim 16, further comprising a third hard metal strip affixed to a third portion of the cutting end and including at least one third full hard metal cutting tooth that is unset.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION
[0037] Referring to
[0038] Each cutting strip 22 is composed of a hard metal material to facilitate cutting metal materials, such as pipes or electrical conduits. The hard metal material may be composed of a hard metal, such as carbide (e.g., tungsten carbide) or cermet, that is harder than the metal material of the body 12. It is desirable to select a grade of hard metal material that has a high amount of toughness and impact resistance. A carbide that lacks good toughness will typically fail by chippage, strippage or carbide fracturing. Moreover, the carbides on prior art carbide blades consist of long extruded carbide strip or strips having a length of 1.5 inches or more and a trapezoidal cross-section attached to the backing steel blade body. Full cutting teeth are ground, pressed, molded, or otherwise formed in the carbide strips prior to them being attached to the body 12, which creates a simple design with low manufacturing complexity and cost.
[0039] Each hard metal cutting strip 22 includes a base portion 24 and a plurality of full cutting teeth 26A, 26B that are integral with the base portion 24. In the illustrated embodiment, each hard metal cutting strip 22 comprises at least two cutting teeth 26A that will be set left, at least two teeth 26B that will be set right (e.g., by approximately 0.005 inches to approximately 0.025 inches), and intermediate gullets 28 disposed between adjacent teeth 26A, 26B. Using strips 22 having a plurality of full hard metal cutting teeth 26 enables the hard metal teeth to be arranged with at a fine tooth pitch (e.g., a pitch finer than or equal to 12 tpi (i.e., having greater than or equal to 12 tpi)), since a plurality of full teeth connected by a baserse can be welded more easily to the body 12. It should be understood that each strip 22 may include only one or more cutting teeth and may be formed without any base portion beneath the cutting teeth. In addition, each strip 122 may include a fewer or a greater number of full cutting teeth 26A, 26B.
[0040] Each full cutting tooth 26A, 26B includes a rake face 30 extending upward from the base portion 24 to a cutting tip 32, and a relief face 34 extending downward from the cutting tip 30 to the base portion 28. Each rake face 30 is disposed at a rake angle (e.g., approximately 10 to 10) relative to a vertical axis Y that is perpendicular to the longitudinal axis X. Each relief face 34 is disposed at a relief angle (e.g., approximately 5 to 45) relative to the vertical axis Y. Each cutting tooth 26 also has a left side face 37 and a right side face 35 extending from the rake face 30 to the relief face 34.
[0041] Each hard metal strip 22 is attached to the cutting edge 14 of the body 12, e.g., by welding, brazing, soldering, or adhesive. In one embodiment, the base portion 24 of each hard metal strip 22 is welded to the cutting edge 14 via a more ductile weld fusion zone 36. Each weld fusion zone 36 may be composed of an alloying material that results in a more ductile welded joint. For example, an alloying material such as nickel or a nickel alloy may be sandwiched between the strip 22 and blade body 12 or fed into the weld zone between the strip 22 and the blade body 12. This blended composition of the resulting weld joint results in a ductile material that enables stronger plastic deformation of the weld zone during a setting operation. Without the additional ductility, the weld seam would crack, and the set carbide strips and teeth would be prone to fracturing, chipping, or breaking off during the setting process or use of the saw blade.
[0042] Alternatively, as shown in
[0043] Because they are made of a hard metal, the teeth 26 on the strips 22 cannot be set left or right in the traditional manner by bending the teeth because this would require a great deal of force and risk fracturing the strips 22. Instead, in an embodiment illustrated in
[0044] Similarly, left and right side faces 37B, 35B of teeth 26B on a second hard metal strip 22B that is adjacent to the first hard metal strip 22A may be ground or otherwise formed or shaped (either before or after being attached to the body 12) so that the right side face 35B is at a first right angle R1 (e.g., approximately 2 to 10) and the left side face 37A is at a second right angle R2 (e.g., approximately 0 to 20) relative to the vertical axis Y of the body 12. The first and second right angles R1, R2 may be equal so that, when viewed from the rake face 30, the second teeth 26A have a parallelogram appearance. Alternatively, the first and second right angles R1, R2 may be different.
[0045] The first and second left angles L1, L2 of the side faces 37A, 35A of the first teeth 26A on the first strip 22A effectively cause the first teeth 26A to perform as though they are set to the left. The first and second right angles R1, R2 of the side faces 35B, 37B of the second teeth 26B on the first strip 22B effectively cause the first teeth 26B to perform as though they are set to the right. For example, in the illustrated embodiment, the strips 22A, 22B, each having two teeth 26A, 26B, are set in a L-R-L-R- pattern so that two consecutive teeth 26A are set left followed by two consecutive teeth 26B set right. Alternatively, there may be a third strip in each sequence in which the side faces are not ground or are formed generally parallel to the vertical axis Y, such that the teeth on the third strip perform as though they are unset or raker teeth. In that embodiment, the strips 22 could be set in a L-R-U-L-R-U- pattern. Other set patterns may be used, such as light left-light right-heavy left-heavy right- or unset-left-right-left-right-. The set angles of the left set teeth and the right set teeth may be the same or may be different.
[0046] Referring also to
[0047] The strips 22A, 22B of
[0048] In the illustrated embodiment, the strips 22A, 22B, each having two teeth 26A, 26B, are set in a L-R-L-R- pattern so that two consecutive teeth 26A are set left followed by two consecutive teeth 26B set right. Alternatively, there may be a third strip in each sequence in which the side faces are formed generally parallel to the vertical axis Y and is not set left or right, such that the teeth on the third strip are unset or raker teeth. In that embodiment, the strips could be set in a L-R-U-L-R-U- pattern. Other set patterns may be used, such as light left-light right-heavy left-heavy right- or unset-left-right-left-right-. In each embodiment, the set angles of the left set teeth and the right set teeth, and the angles of the side faces of the left and right set teeth, may be the same or may be different than one another.
[0049] In an experiment, saw blades having carbide strips attached to the blade body by a ductile weld fusion zone (e.g., containing a 0.005 inch nickel shim), according to the embodiment of
TABLE-US-00001 TABLE 1 Saw Blades with Carbide Strips Attached by Conventional Weld Sample Lateral Force At Fracture (lbf) Notes 1 240 Clean Break 2 238 Clean Break 3 237 Clean Break 4 243 Partial Break Avg. 240
TABLE-US-00002 TABLE 2 Saw Blades with Carbide Strips Attached By Ductile Weld Fusion Zone Containing Nickel Lateral Force At Bend in Weld Lateral Force at Sample Fusion zone (lbf) Fracture (lbf) Notes 1 124 296 Carbide strip pushed over smoothly until break 2 117 246 Carbide strip pushed over smoothly until break 3 118 222 Carbide strip pushed over smoothly until break 4 161 416 Carbide strip pushed over smoothly until break Avg. 140 304
[0050] Referring to
[0051] Each cutting strip 122 is composed of a hard metal material to facilitate cutting metal materials, such as pipes or electrical conduits. The hard metal material may be composed of a hard metal, such as carbide (e.g., tungsten carbide) or cermet, that is harder than the metal material of the body 112. It is desirable to select a grade of hard metal material that has a high amount of toughness and impact resistance. A carbide that lacks good toughness will typically fail by chippage, strippage or carbide fracturing. Full cutting teeth are ground, pressed, molded, or otherwise formed in the carbide strip prior to the strips being attached to the body 112, which creates a simple design with low manufacturing complexity and cost.
[0052] Each hard metal cutting strip 122 includes a base portion 124 and a plurality of full cutting teeth 126A, 126B that are integral with the base portion 124. In the illustrated embodiment, each hard metal cutting strip 122 comprises at least two cutting teeth 126A to be set left, at least two cutting teeth 126B to be set right, and intermediate gullets 128 disposed between adjacent teeth 126A, 126B. Using strips 122 having a plurality of full hard metal cutting teeth 126 enables hard metal teeth to be arranged with at a fine tooth pitch (e.g., a pitch finer than or equal to 12 tpi (i.e., having greater than or equal to 12 tpi)), since a base 124 supporting a plurality of teeth 126A, 126B can be welded more easily to the body 112. It should be understood that each strip 122 may include one or more cutting teeth without any base portion beneath the cutting teeth. Alternatively, each strip 122 may include a fewer (e.g., one) or a greater (e.g., three or four) number of full cutting teeth 126.
[0053] Each full cutting tooth 126A, 126B includes a rake face 130 extending upward from the base portion 124 to a cutting tip 132, and a relief face 134 extending downward from the cutting tip 130 toward the base portion 128. Each rake face 130 is disposed at a rake angle (e.g., approximately 10 to 10) relative to a vertical axis Y that is perpendicular to the longitudinal axis X. Each relief face 134 is disposed at a relief angle (e.g., approximately 5 to 45) relative to the vertical axis Y. Each cutting tooth 126 also has a left side face 135A and a right side face 135B extending from the rake face 130 to the relief face 134. As shown in
[0054] Each hard metal strip 122 is attached to the cutting edge 114 of the body 112, e.g., by welding, brazing, soldering, or adhesive. In an illustrated embodiment, the base portion 124 of each hard metal strip 122 may be welded to the cutting edge 114 via a more ductile weld fusion zone 136. Each weld fusion zone 136 may be composed of an alloying material that results in a more ductile welded joint. For example, an alloying material such as nickel or a nickel alloy may be sandwiched between the strip 122 and blade body 112 or fed into the weld zone between the strip 122 and the blade body 112.
[0055] Because they are made of a hard metal, the teeth 126 on the strips 122 cannot be set left or right in the traditional manner by bending the teeth because this would require a great deal of force and risk fracturing the strips 122. Instead, as shown in
[0056] Similarly, the right side faces 135B of a one or more of the teeth 126B may be ground or otherwise formed or shaped (either before or after being attached to the body 112) so that a portion of left side face 135B is removed to create a right side recess 139B and a new left side face 135B that is recessed from a right side face 113 of the body 112. In the illustrated embodiment, if this forming operation is performed after attaching the strip 122 to the body, the right side recess 139A may extend at least partially into or through one or more of the base portion 124 of the strip 122, the weld fusion zone 136, and the right side face 113 of the body 112. In the embodiment shown in
[0057] Forming the recesses 139A, 139B in an alternating pattern of the side surfaces 135, 137 of the teeth 126A, 126B makes the teeth function as though they are set in an alternating left and right pattern. In the illustrated embodiment, with fine pitch teeth, it may be more expedient to form each recess 139A, 139B across two teeth 124A, 126B, so that the teeth are then set in a L-L-R-R- pattern. Alternatively, a third tooth or set of teeth in each sequence may not be formed to have a recess or may be formed with a recess on both side faces of the tooth, such that these third teeth are unset or raker teeth. In that embodiment, the teeth could be set in a L-L-R-R-U- pattern or a L-L-R-R-U- pattern. Other set patterns may be used, such as L-R-L-R, L-R-L-R, U, and light left-light right-heavy left-heavy right- or unset-left-right-left-right-. In each embodiment, the set angles of the left set teeth and the right set teeth, and the angles of the side faces of the left and right set teeth, may be the same or may be different than one another.
[0058] Referring to
[0059] The above-described embodiments are not limited for use in reciprocating saw blades. Rather they can be used in any number of different types of saw blades, such as, for example, jigsaw blades, bandsaw blades, and holesaws. For example,
[0060]
[0061] The cutting portion 618 includes one or more hard metal cutting strips 630 attached to the front cutting portion 622. The hard metal cutting strip(s) 630 having teeth 632 with portions of their top and bottom faces 634, 636 removed, similar to the hard metal cutting strip 122 described above with respect to
[0062] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms a, an, and the may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms comprises, comprising, including, and having, are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.
[0063] When an element or layer is referred to as being on, engaged to, connected to, or coupled to another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being directly on, directly engaged to, directly connected to, or directly coupled to another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., between versus directly between, adjacent versus directly adjacent, etc.). As used herein, the term and/or includes any and all combinations of one or more of the associated listed items.
[0064] Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as first, second, and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.
[0065] Terms of degree such as generally, substantially, approximately, and about may be used herein when describing the relative positions, sizes, dimensions, or values of various elements, components, regions, layers and/or sections. These terms mean that such relative positions, sizes, dimensions, or values are within the defined range or comparison (e.g., equal or close to equal) with sufficient precision as would be understood by one of ordinary skill in the art in the context of the various elements, components, regions, layers and/or sections being described.
[0066] Numerous modifications may be made to the exemplary implementations described above. These and other implementations are within the scope of this application.