Variable Height, High Performance, Bandsaw Blade and Method of Manufacture Therefor

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 performance bandsaw blades, for example blades used in cutting stainless steel and the like, have been developed. One particular method employs a cammed back 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 approach provides for "surging" of the blade as the back 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 guiding the back edge.

While these methods represent advances over blades 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 operate and use.

It is therefore an object of this invention to provide a high performance bandsaw blade operable with present equipment and manufactured using standard and available equipment, yet providing a performance price benefit which is comparable to or surpasses the surging blades previously described. Other 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.

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 the height of a tooth at the end of the pattern by between, preferably ten and twenty-five thousandths of an inch, more preferably between fifteen and twenty thousandths of an inch, and in one illustrated embodiment, about twenty thousandths of an inch.

In various embodiments of the invention, the repeating tooth pattern can be between four and twelve inches 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 alternates 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 35-48% of tooth pitch.

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 ten and twenty-five thousandths of an inch, preferably between fifteen and twenty thousandths of an inch, and more preferably, is about twenty thousandths of an inch.

Other objects, features and advantages of the invention will be apparent from the following description taken together with the drawings in which:

FIGS. 1A, 1B, and 1C are elevation views of a section of a bandsaw blade manufactured in accordance with a preferred embodiment of the invention; and

FIGS. 2A, 2B and 2C are top views of the bandsaw blades of FIGS. 1A, 1B and 1C, respective, in accordance with a preferred embodiment of the invention .

Referring to FIGS. 1A, 1B and 1C, 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 24 to the end 22 of a repeating pattern of teeth. According to the invention, the height difference of the teeth over the length of each repeating pattern is between about ten and twenty-five thousandths of an inch, preferably between fifteen and twenty thousandths of an inch, and is most preferably about twenty thousandths 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 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 depth between teeth is a function of the pitch and is preferably between 35 and 48% of pitch.

Referring to FIGS. 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 increasing 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. Thus, in the preferred and illustrated embodiment of the invention, there is provided a 20 thousandths of an inch change in tooth height over a length of about 6 inches.

The manufacture of the bandsaw blades illustrated in FIGS. 1A, 1B, 1C, 2A, 2B and 2C is performed using a 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 a tooth will automatically be a monotonically increasing function of the tooth height. Accordingly, the manufacturing 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.