Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23D—PLANING; SLOTTING; SHEARING; BROACHING; SAWING; FILING; SCRAPING; LIKE OPERATIONS FOR WORKING METAL BY REMOVING MATERIAL, NOT OTHERWISE PROVIDED FOR
  • B23D61/00—Tools for sawing machines or sawing devices; Clamping devices for these tools
  • B23D61/12—Straight saw blades; Strap saw blades
  • B23D61/121—Types of set; Variable teeth, e.g. variable in height or gullet depth; Varying pitch; Details of gullet
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23D—PLANING; SLOTTING; SHEARING; BROACHING; SAWING; FILING; SCRAPING; LIKE OPERATIONS FOR WORKING METAL BY REMOVING MATERIAL, NOT OTHERWISE PROVIDED FOR
  • B23D61/00—Tools for sawing machines or sawing devices; Clamping devices for these tools
  • B23D61/02—Circular saw blades
  • B23D61/021—Types of set; Variable teeth, e.g. variable in height or gullet depth; Varying pitch; Details of gullet
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T83/00—Cutting
  • Y10T83/929—Tool or tool with support
  • Y10T83/9319—Toothed blade or tooth therefor
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T83/00—Cutting
  • Y10T83/929—Tool or tool with support
  • Y10T83/9319—Toothed blade or tooth therefor
  • Y10T83/9358—Series of dissimilar teeth

Definitions

• Certain saw blades such as bandsaw blades, are commonly made with recurring variations in the shape, spacing, height, and setting of the teeth, as well as in the width of the saw blade body.
• setting or “set” it is meant that certain teeth or portions of certain teeth slant to the left or right of a centerline of the blade. Most of these variations serve to improve the properties of the blade for certain specific applications. However, the same variations often decrease the usefulness of the blade for other applications.
• bandsawing especially bandsawing metal, presents problems not commonly encountered in other sawing methods.
• the bandsaw blade is usually made thin and narrow, which limits the total feed force that can be applied to force the teeth into the sawn material and makes the blade very- flexible.
• To get a smooth cut several teeth must be actively engaged in cutting simultaneously, which allows only a relatively small feed force for each of the teeth. Small feed force leads to small cutting depth which, especially for tough materials, means unstable chip formation and excessive wear.
• the fewer the number of teeth that are actively engaged in cutting simultaneously the greater the effect of the sudden change in tension when a tooth leaves or enters the cut, and problems associated with self-induced vibrations of the saw blade vertically, laterally, or torsionally may occur. For example, such vibrations tend to lead to uneven cut surfaces and noise.
• Variations in tooth shape may serve to make the teeth cut several narrow and thick chips rather than fewer thin and wide chips. Formation of numerous narrow and thick chips leads to less wear, less friction against the cut sides, and, usually, better lateral stability than formation of fewer thin and wide chips.
• many blades having teeth with variations in shape require extra manufacturing operations and are, in consequence, expensive to make, or if desired, to resharpen.
• Variations in tooth spacing can lower the tendency of self-induced chatter vibrations when sawing thick material, and tends to minimize noise from the sawing operation. There is, however, a tendency for teeth with variations in spacing to become unevenly worn, which may later contribute to transverse forces and crooked cutting.
• Tooth height may be varied in various ways to serve different purposes. If straight teeth are longer than others, their side faces tend to guide the blade and produce a straight and narrow cut. However, straight teeth are unlikely to straighten a cut if it starts to veer to one side. If high straight teeth are combined with teeth having variations in setting, multiple narrow thick chips will be cut instead of fewer thin wide chips. This tends to improve the sawing of tough materials, but may leave uneven sides of the cut since only those few teeth set to maximum width shape the final cut surface. In tough material, the combination of high straight teeth and teeth with variations in setting may also be used at slow feed rates so that the high teeth perform the bulk of the actual cutting operation, thus minimizing unstable conditions at small cutting depths.
• a saw blade includes a plurality of recurring groups of teeth, each tooth having a point.
• Each group comprises one high straight tooth without set, an even number of high set teeth with points at a first level, half of the high set teeth being set to the right and half to the left, an even number, greater than the number of high set teeth, of low set teeth with points at a second level lower than the first level, half of the low set teeth being set to the right and half to the left.
• Points of each tooth in the group are at a different distance from a point of a corresponding, immediately preceding tooth. All set teeth in the group have the same amount of set. No high tooth is immediately preceded by another high tooth.
• FIG. 1 is a partial view of a saw blade including recurring groups of teeth according to an embodiment of the present invention
• FIG. 2 is a side view of a group of teeth of a saw blade according to an embodiment of the present invention.
• FIG. 3 is a top view of the group of teeth of FIG. 2.
• a saw blade 21 according to a preferred embodiment of the present invention is seen in FIG. 1 and has teeth arranged in recurring groups 23 of seven teeth 1-7.
• a group 23 of seven teeth preferably includes three teeth 2, 5, 7 that are high teeth and four teeth 1, 3, 4, 6 that are low teeth.
• one of the high teeth is preferably a raker tooth 7 with no angular set, and all other teeth 1-6 are set an equal amount.
• six teeth 1-6 out of the seven total teeth cooperate to shape the final cut surfaces of a workpiece.
• FIGS. 2- 3 generally.
• the high teeth are spread out with one or two of the low teeth between each two high teeth.
• the distance from one high tooth 2, 5, 7 to a preceding high tooth 7, 2, 5 preferably differs within a group 23 of any seven successive teeth to avoid self-induced chatter.
• the depth of the gullets 11-17 between the teeth 1-7, respectively, is preferably varied to make more spacious gullets in front of the high teeth 2, 5, 7 to accommodate the larger amounts of chips produced by them.
• the gullet bottoms R 2 , R 5 , R 7 in front of the high teeth 2, 5, 7 be larger than the gullet bottoms R lf R 3 , R 4 , R 6 in front of the low teeth 1, 3, 4, 6 to facilitate letting the thick chips curl before fracturing.
• a group 23 comprises a plurality of teeth 1-7, and their corresponding immediately preceding gullets 11-17, respectively.
• the group 23 is defined, for purposes of discussion, as beginning after a straight high raker tooth 7 defining the end of a preceding group 23 of teeth.
• the first tooth 1 is a low left set
• the second tooth 2 a high right set tooth
• the third tooth 3 a low left set tooth
• the fourth tooth 4 a low right set
• the fifth tooth 5 a high left set tooth
• the sixth tooth 6 a low right set tooth
• the seventh tooth 7 a high straight tooth without set.
• other arrangements such as a mirror image having teeth arranged in the manner of low right, high left, low right, low left, high right, low left and high straight, would be equally useful.
• tooth shape and distance to the preceding tooth, in millimeters, for the teeth of a recurring group are: D x 5.1 mm; D 2 6.05 mm; D 3 4.8 mm; D 4 4.91 mm; D 5 5.68 mm; D 6 5.6 mm; D 7 5.96 mm.
• Gullet heights Hi-H i.e., the height of the point of the tooth from the bottom of the gullet, for each of the gullets preceding each of the teeth 1-7 are preferably H x 2.650 mm; H 2 2.910 mm; H 3 2.540 mm; H 4 2.600 mm; H 5 2.820 mm; H 6 2.750 mm; and H 7 2.860 mm.
• Radii of the gullet bottoms Rj-R ? are preferably R x 1.219 mm; R 2 1.795 mm; R 3 1.105 mm; R 4 1.199 mm; R 5 1.615 mm; R 6 1.481 mm; and R 7 1.775 mm. Heights of the high teeth 2, 5, and 7 are preferably 0.075 mm higher than heights of the low teeth 1, 3, 4, and 6. All of the teeth 1-7 preferably have a rake angle a. of 6° and a relief angle ⁇ of 37°.
• All high teeth preferably have their points at one level to minimize differences in wear rates during cutting at low feed rates and thereby extend the useful life of the blade, and all low teeth preferably have their points at another level. All set teeth preferably have the same amount of set to facilitate forming a smooth surface on the workpiece.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Drilling Tools (AREA)
• Processing Of Stones Or Stones Resemblance Materials (AREA)
• Sawing (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=24070501

Family Applications (1)

Country Status (4)

Cited By (1)

Families Citing this family (48)

Citations (4)

Family Cites Families (4)

• 1995
  • 1995-08-28 US US08/519,942 patent/US5603252A/en not_active Expired - Fee Related
• 1996
  • 1996-08-23 JP JP9510183A patent/JPH11512031A/ja not_active Ceased
  • 1996-08-23 CA CA002229413A patent/CA2229413A1/en not_active Abandoned
  • 1996-08-23 WO PCT/SE1996/001044 patent/WO1997007920A1/en not_active Ceased

Patent Citations (4)

Also Published As

Similar Documents

Legal Events