AU663932B2

AU663932B2 - Variable height, high performance, bandsaw blade and method of manufacture therefor

Info

Publication number: AU663932B2
Application number: AU36924/93A
Authority: AU
Inventors: Ralph Stoddard
Original assignee: LS Starrett Co
Current assignee: LS Starrett Co
Priority date: 1992-05-11
Filing date: 1993-04-15
Publication date: 1995-10-26
Anticipated expiration: 2013-04-15
Also published as: GB2266861A; DE4315517A1; AU3692493A; JPH06190629A; BR9301793A; GB2266861B; GB9308304D0

Description

663932

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION i i i F i:i i i j 3 i i i 'i i: i i i I r :i f i i i i i i i i ri

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4 t NAME OF APPLICANT(S): The L. S. Starrett Company ADDRESS FOR SERVICE: DAVIES COLLISON CAVE Patent Attorneys 1 Little Collins Street, Melbourie, 3000.

INVENTION TITLE: Variable height, high performance, bandsaw blade and method of manufacture therefor The following statement is a full description of this invention, including the best method of performing it known to me/us:- 4 II 44144 16 la- *Bachrn r uf 1hp Tie !il The invention relates generally to high performance bandsaw blades and in particular, to those bandsaw blades which have variable height, pitch, and set.

A typical measure of bandsaw blade performance is the throughput in comparison to the price paid for the blade and/or the equipment needed for running it. Over the past two decades, many different approaches to high o performance bandsaw blades, for example blades used in cutting stainless steel and the like, have been 0 0 oOOo 15 developed. One particular method employs a cammed back j edge which provides a "surging" of the blade during cutting. The back edge in effect causes the blade to move relative to and into the metal being cut. Another 90 approach provides for "surging" of the blade as the back 20 edge of the blade varies to provide an undulating surface which causes the blade to oscillate about an imaginary pivot point centered between the rollers pressing on and °000 guiding the back edge.

While these methods represent advances over blades So. 25 used decades ago, they typically require either major readjustment of the bandsaw blade equipment, the use of entirely new equipment since the older equipment is not adaptable to the new blades, major and substantial additional costs in manufacturing the blades (the cost being absorbed as the performance of the blade increases), or blades which are highly specialized and are accordingly expensive to 9perate and use.

It is therefore awr\object of this invention to provide a high performance bandsaw blade operable with present equipment and manufactured using standard and ,r b-2available equipment, yet providing a performance price benefit which is comparable to or surpasses the surging blades previously described. Other preferred objects of the invention are a high performance bandsaw blade which can be manufactured using existing equipment, and which has relatively low or no additional costs associated with the manufacturing process wherein the blade is used. Yet further objects of the invention are a reliable, simple to operate, simple to use, high performance, high speed bandsaw blade.

According to a first aspect of the present invention there is provided a bandsaw blade having a repeating tooth pattern, ~each set tooth of each tooth pattern of said repeating tooth patterns having a set which has a monotonically nondecreasing functional relationship to the height of said tooth, and a first tooth of each repeating tooth pattern having a tooth height which varies from a beginning of said pattern to an end of said pattern, said tooth height at the end of the repeating pattern being between about 3.81 x 10- 4 m to 5.08 x greater than the tooth height at the beginning of the repeating pattern.

According to a second aspect of the present invention i there is provided a bandsaw blade having a repeating tooth I 25 pattern, each set tooth of each tooth pattern of said repeating I, t tooth patterns having a set which increases with the height of the tooth, each repeating tooth pattern having a length of about 30 0.1524m, and the teeth of each repeating tooth pattern having a tooth height which increases linearly over the repeating pattern, the tooth height at the end of the repeating pattern being between about 3.81 x 10- 4 m and 5.08 x 10- 4 m greater than the tooth height at the beginning of the repeating pattern, the teeth having a repeating specified set pattern including a raker tooth followed by a predetermined number of set teeth, 9 S0822,p:operUkfy,36924932342 M 1 t -3the set alternating in sequence along the teeth of the set pattern, and set teeth having a variable pitch.

According to a third aspect of the present invention there is provided a method of manufacturing a bandsaw blade comprising the steps of cutting repeating patterns of teeth, the height of each tooth increasing monotonically through said repeating pattern, the height difference through a pattern being between 3.81 x 10-4m and 5.08 x 10- 4 m, and setting selected ones of said teeth, said set being a monotonically increasing function of the tooth height.

An embodiment of the invention relates to a bandsaw blade which features a straight back edge and a repeating tooth pattern. Each set tooth of each repeating tooth pattern has a set which is monotonically related to the height of the tooth. Each tooth of each repeating tooth pattern has a tooth height in which a tooth at the beginning of the pattern has a height which is less than to the height of a tooth at the end of the pattern by between, preferably fifteen and twenty thousandths of an inch 3.81 x 10- 4 m Sto 5.08 x 10- 4 and in one illustrated embodiment, about twenty thousandths of an inch (5.08 x 10- 4 m) In various embodiments of the invention, the repeating tooth pattern can be between four and twelve inches (i.e.

between 0.1016m and 0,3048m) in length, and preferably is about six inches in length. This matches the typical length of a present day cutter used for manufacturing bandsaw blades. The bandsaw blade further has a tooth height which preferably increases linearly over the repeating pattern. In another aspect of the invention, the bandsaw blade teeth have a repeating, specified, set pattern which includes a raker tooth followed by a predetermined number of set teeth. The direction of set of the set teeth alternateu in sequence along the blade. The teeth also can have, according to a preferred embodiment of the invention, a variable pitch, Typically, the tooth gullet depth is approximately between /J 35-48% of tooth pitch.

9 sog22p: peAkny,36924.93.234.J r i; r p -7 -4- The method of the invention for manufacturing a bandsaw blade features the steps of cutting repeating patterns of teeth, the height of the tooth at the beginning of the pattern being less than the height of the tooth at the end of the pattern, and setting selected ones of the teeth, the set being a monotonically increasing function of the tooth height. The difference in height from beginning to end of each repeating pattern is between about fifteen and twenty thousandths of an inch, and preferably, is about twenty thousandths of an inch.

Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings in which:- Figures 1A, lB and 1C are elevation views of a section of a bandsaw blade manufactured in accordance with a preferred embodiment of the invention; and t tFigures 2A, 2B and 2C are top views of the bandsaw blades of Figures 1A, lB and 1C, respective, in accordance with a preferred embodiment of the invention.

Referring to Figures 1A, lB and IC, a typical bandsaw blade 10, in accordance with the illustrated embodiment of the invention, has a plurality of teeth 12 in a body 13 having a straight back edge 14. The teeth 12 comprises a tip section 16 and a gullet section 18. In accordance with a preferred embodiment of the invention, the points of the teeth tips lie along an inclined imaginary plane 20 which extends from the beginning 22 to the end 24 of a repeating pattern of teeth. According to an embodiment of the invention, the height difference of the teeth over the length p 30 of each repeating pattern is between about fifteen and twenty thousandths of an inch 3.81 x 10- 4 m to 5.08 x 104m), and is preferably about twenty thousandth of an inch. The teeth in each repeating pattern accordingly increase monotonically in height, in accordance with this illustrated embodiment of the invention, from the beginning of the pattern to the end of the pattern. In other embodiments of the invention, the change in height between the ends of the n{ 950822,p:oprkafy,36924-93.234,4 i I i ii i i i i I i r i i I n A 1 ii -4a pattern may not be monotonically increasing. In this illustrated embodiment, a variable pitch blade is described so that the distance between teeth tips varies. The gullet j depth between teeth is a function of the pitch and is preferably between 35 and 48% of pitch.

i Referring to Figures 2A, 2B and 2C, the set of the teeth is determined by a repeating set pattern which is typically, due to manufacturing constraints, synchronous with the repeating tooth pattern; and can, for example, include multiple occurrences of a raker tooth 30 followed by alternately right and left set teeth 32. In accordance with the illustrated embodiment of the invention, the set of a tooth increases with incr'easing height. Accordingly, the set of a tooth such as tooth 40 is greater than the set of a tooth such as tooth 42.

In accordance with the illustrated embodiment of the invention, various set patterns and pitch variations can be employed. The overall length of a typical tooth pattern is 6 inches (0.1524m). Thus, in the preferred and illustrated embodiment of the invention, there is provided a thousandths of an inch change in tooth height over a length of about 6 inches.

The manufacture of the bandsaw blades illustrated in fi Figures 1A, 1B, IC, 2A, 2B and 2C is performed using a

I

K 950822,p\opery,3692493,K4K 4 ii standard bandsaw manufacturing process. The cutters are adjusted and positioned to enable the selected repeating tooth pattern, as described above, to be created. The teeth are then set in a standard fashion, and the set of I 5 a tooth will automatically be a monotonically increasing function of the tooth height. Accordingly, the Smanufacturing process closely resembles the standard process for making a bandsaw blade.

Additions, deletions, and other modifications of the preferred and illustrated embodiments of the invention will be apparent to those practiced in the art and are within the scope of the following claims: ML I I I

Claims

1. A bandsaw blade having a repeating tooth pattern, each set tooth of each tooth pattern of said repeating tooth patterns having a set which has a monotonically non- decreasing functional relationship to the height of said tooth, and a first tooth of each repeating tooth pattern having a tooth height which varies from a beginning of said pattern to an end of said pattern, said tooth height at the end of the repeating pattern being between about 3.81 x 10"'m to 5.08 x greater than the tooth height at the beginning of the oa°o repeating pattern. 1 15

2. A bandsaw blade according to claim 1 wherein said °repeating tooth pattern is between 0.1016m and 0.3048m in o. length.

3. A bandsaw blade according to claim 2 wherein said repeating tooth pattern is about 0.1524m in length.

4. A bandsaw blade according to claim 1 wherein said tooth height increases linearly over said repeating pattern. 4 O O

5. A bandsaw blade according to claim 1 wherein said teeth have a repeating specified set pattern comprising a raker tooth followed by a predetermined number of set teeth, the set alternating in sequence along said teeth of the set pattern.

6. A bandsaw blade according to claim 1 wherein said teeth have a variable pitch.

7. A bandsaw blade according to claim 6 wherein said teeth have a gullet depth of between about 35% and 48% of tooth pitch. 950822,p:eopc .ay,36924.93.23 4 ,6 r a i 111 1-1-1

8. A bandsaw blade having a repeating toth pattern, each set tooth of each tooth pattern of said repeating tooth patterns having a set which increases with the height of the tooth, each repeating tooth pattern having a length of about 0.1524m, and the teeth of each repeating tooth pattern having a tooth height which increases linearly over the repeating pattern, the tooth height at the end of the repeating pattern being between about 3.81 x 10 4 m and 5.08 x 10" 4 m greater than the tooth height at the beginning of the repeating pattern, the o teeth having a repeating specified set pattern including a raker tooth followed by a predetermined number of set teeth, e °0 the set alternating in sequence along the teeth of the set 15 pattern, and set teeth having a variable pitch. I

9. A method of manufacturing a bandsaw blade comprising the steps of cutting repeating patterns of teeth, the height of each tooth increasing monotonically through said repeating Spattern, the height difference through a pattern being 4-4 between 3.81 x 10'm and 5.08 x 10' 4 m, and setting selected ones of said teeth, said set being a monotonically increasing function of the tooth height.

A bandsaw blade substantially as hereinbefore described with reference to the drawings.

11. A method substantially as hereinbefore described with reference to the accompanying drawings. DATED this 22nd day of August, 1995. THE L.S. STARRETT COMPANY by its Patent Attorneys DAVIES COLLISON CAVE 950822,p:\opc\nay,36924-93,234,7 C, ABSTRACT OF THE DISCLOSURE A high performance, moderate cost bandsaw blade has a unique tooth configuration which enables it to provide high performance, while using standard manufacturing processes and available bandsaw equipment. The bandsaw blade has a straight back edge and a repeating tooth pattern wherein each set tooth, of each repeating tooth pattern has a set which is a monotonically increasing function of the height of the tooth. The height of each tooth in the repeating tooth pattern increases from the first tooth of the pattern to the last tooth of the pattern. The height difference between the beginning and end of a tooth pattern is .preferably on the order of fifteen to twenty thousandths 0 15 of an inch, and the length of a repeating pattern is 9 0 typically about six inches to match a standard cutter. 0 01 fj

29693.B11 m.-