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
  • B23D61/1216—Repeating pattern of groups having three or more teeth
• • 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
  • B23D61/1212—Varying pitch

Definitions

• the present invention relates to a versatile bandsaw blade comprising a blade beam carrying a plurality of cutting teeth.
• Bandsawing is the preferred method for cutting long pieces of metal into predetermined lengths as a preparation for other operations such as welding, turning and milling.
• Bandsaw blades for the above-described applications are normally designed with a variable pitch. This means that the distance between the teeth varies in a predetermined way, dividing said teeth into groups, each group repeating the same variation in tooth distance, so that harmonic vibrations are reduced when sawing.
• the relative size between the biggest tooth distance in the group and the smallest tooth distance is typically >1.4.
• Such a blade consists of groups of teeth, each group typically of a length of 1.5".
• the number of teeth in each group varies with the pitch of the blade but is typically odd in number.
• a blade with a 6/10 teeth per inch pitch typically has 11 teeth in each group.
• the meaning of the designation "6/10" is that the biggest tooth gullet in the group has a size corresponding to a regular 6 TPI blade and the smallest gullet has a size corresponding to a 10 TPI blade.
• the clearance angle of the teeth is typically 35° and the clearance side of the tooth, or the back of the tooth, is straight, leading to a small bottom radius of the gullet.
• the size of the bottom radius of the gullet is typically less than a 1/2 of the dept of the gullet.
• the deep gullets with small radii increase the risk of swarf being locked in the gullet.
• the swarf is often in the form of spiral shaped chips that get trapped between the sides of the deep, narrow gullets.
• the radius of such chips is typically about 1/2 of the depth of the gullets i.e. bigger than the radius of the gullets, thereby causing the chips to be looked in the bottom of the gullets.
• the setting pattern of such a group normally follows the order: -0-R-L-R-L-R-L-R-L-R-L-R-L-L-i.e. the first tooth in the group is unset, the next is set to the right, the following to the left etc. with only one unset tooth per group.
• the setting operation is done one group at a time. When setting up the setting machine it is of great importance that the correct tooth is left unset. If the wrong tooth is left unset the setting hammers will hit the other teeth in the group in such a way that the teeth or the edges are deformed in an unwanted way. This leads to high amount of scrapped material in the production of such bandsaw blades.
• the design of the gullets of traditional blades of this kind is such that all gullets in the group are proportional i.e. they have the same relationship between tooth distance, gullet depth and gullet radius.
• the chip holding capacity of each gullet in the group is proportional to the cross sectional area of the gullet.
• the chip holding capacity of the gullets in such a design is limited by the cross sectional area of the smallest gullet in the group.
• the other, bigger gullets in the group are unnecessarily big because all their dimensions are proportional to the tooth distance in relation to the smallest gullet.
• a gullet that has a tooth distance that is 20% greater than the smallest gullet in the group will need 20% more chip capacity than the smallest gullet.
• the present invention teaches a new tooth design that overcomes all of the problems described above.
• the bandsaw blade with such teeth is presented in the following claim 1.
• Various advantageous embodiments of the present invention can be found in the dependent claims.
• Figure 1 schematically shows a known bandsaw blade
• Figure 2 schematically shows a known bandsaw blade with teeth divided into groups
• Figure 3 schematically shows teeth of a bandsaw blade according to the present invention
• Figure 4 schematically shows an inventive bandsaw blade with a variable tooth distance.
• Figure 1 shows a bandsaw blade 1 with teeth 11 , 12 separated by a gullet 13.
• Parameters pertinent to the present invention are the tooth distance A, the clearance angle B, the radius C of the gullet 13, and the depth D of the gullet 13.
• Figure 2 shows a known bandsaw blade where the teeth are divided into groups, each group repeating the same variation in tooth distance. The figure shows that the smallest gullet 13a and the largest gullet 13b differ in all the above- mentioned parameters.
• the smallest gullet is not able to handle as much swarf as the largest gullet.
• the largest gullet is on the other hand deeper than the smallest gullet, reducing the beam strength.
• Figure 3 shows a versatile bandsaw blade according to the present invention presents a tooth design with a tooth that is provided with a tooth edge stronger than on previous designs. This is achieved by using clearance angles B' of the teeth 11', 12' that is smaller than 35°, for example 30°, and a strong base of the tooth.
• the back 12'a of the tooth 12' is curved 12'b, for the sake of simplicity shown on the tooth 12', the same is true for tooth 11' and every other tooth, to lead to a large bottom gullet 13', the radius C of which is larger than 1/2 of the depth D' of the gullet 13'.
• the radius C can for instance be approximately 3/4 of the depth D' of the gullet 13'.
• the setting pattern of the new blade is -O-R-L-0-R-L- etc.
• the combination of the small difference between the biggest and the smallest gullets and the set pattern will allow the blade to be set in different ways. It does not matter which tooth is left unset, set to the right, or set to the left. When producing such a blade it therefore does not require the difficult set up procedure required by the known design and the risk of destroyed teeth and high scrap numbers is eliminated.
• the number of teeth in each combo group can be any number >4.
• the design of the gullets of the blade according to the present invention is such that the depth and radius of any gullet is proportional to the square root of the relation between the tooth distance of this any gullet and the tooth distance of the smallest gullet in the group of this any gullet.
• a gullet that has a tooth distance that is 20% greater than the smallest gullet in the group will need 20% more chip capacity than the smallest gullet.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Sawing (AREA)
• Component Parts Of Construction Machinery (AREA)
• Harvester Elements (AREA)
• Food-Manufacturing Devices (AREA)
• Processing Of Stones Or Stones Resemblance Materials (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (7)

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Citations (7)

Family Cites Families (17)

• 2002
  • 2002-12-20 US US10/323,841 patent/US7178441B2/en not_active Expired - Lifetime
• 2003
  • 2003-12-16 AU AU2003303189A patent/AU2003303189A1/en not_active Abandoned
  • 2003-12-16 CN CNB2003801068016A patent/CN100453230C/zh not_active Expired - Fee Related
  • 2003-12-16 JP JP2004561866A patent/JP4813799B2/ja not_active Expired - Fee Related
  • 2003-12-16 DE DE10393928.8T patent/DE10393928B4/de not_active Expired - Lifetime
  • 2003-12-16 AT AT0930803A patent/AT500866B1/de not_active IP Right Cessation
  • 2003-12-16 WO PCT/IB2003/006001 patent/WO2004056522A1/en not_active Ceased

Patent Citations (7)

Non-Patent Citations (1)

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