The present invention relates to the field of tree felling and, more particularly, relates to a tooth for a circular saw or a mower drum.
Tree felling machines typically include a circular saw disk which rotates at high speed. The saw disk has several teeth mounted on holders all around its periphery. The saw disk is moved horizontally through the tree, and as it advances, it creates a kerf or cut in the trunk of the tree.
A tooth for a circular saw generally has a mounting end and a cutting end and four sides diverging out from the mounting to the cutting end. The four sides are identical with a straight, linear profile. The cutting end is provided with four pointed tips at its corners, and four cutting edges extend between the cutting tips.
In the field of tree felling, the kerf refers to the width of the cut made by a saw in the trunk of the tree. The kerf of a typical four-sided tooth is thus the width of either one of the cutting edges, which also corresponds to the distance between two adjacent cutting tips.
In some applications, there is a need to increase the kerf of the teeth. In order for a circular saw to operate smoothly and steadily in high energy applications, the disk has to be substantial enough to absorb vibrations and avoid wobbling. The circular disk must be able to advance within the tree without interference, and thus the saw teeth must make a cut large enough for the disk to pass through the kerf.
Increasing the kerf also allows for providing more clearance for the outer, exposed side of the tooth and holder, as it bites into the tree. In other words, the distance between the cutting end and the mounting end of a tooth must be great enough to ensure that the cutting edge remains the sole portion of the tooth in contact with the tree, even as the tooth wears, otherwise the efficiency of the cutting operation is reduced. The holder and bolt retaining the tooth should not wear upon the tree.
One proposed solution for increasing the kerf of a circular saw tooth consists in increasing its height. However, increasing the height of the tooth also increases the stress and load applied on the rotating disk, resulting in energy losses. Indeed, a longer tooth tends to increase the wear and tear of the disk, since the impact on the cutting edge of the tooth occurs further away from the periphery of the disk (i.e. the radial distance between the point of impact of the tooth and the center of the disk is greater), thereby increasing stress on the rotating disk.
Another solution consists in machining the rotating disk so that the outer side of tooth extends slightly more outwardly, with an “open angle”, which can also increase the side clearance of the tooth and holder, but can tend to tear the tooth off the rotating disk. Such an outwardly affixed tooth also tends to increase the stress on the tooth because the tooth tends to be “ripped-off” due to an increased moment resulting from the outwardly-disposed tooth.
Another aspect to consider is that, in most cases, the teeth are mounted on existing holders which have a specific size and configuration. In order to avoid having to replace existing holders or saw, the teeth must have certain specific characteristics so that they can still be mounted on existing holders.
In some application, it would also be desirable to reduce as much as possible the possibility of the tooth to move or wobble within its holder. It would also be desirable to increase the pocket formed by the front end of the tooth.
In view of the above, there is thus a need for an improved saw tooth that would be able to overcome or at least minimize some of the above-discussed concerns. It would be desirable for the improved saw tooth to have a wider kerf than existing four-sided saw teeth, without increasing its height. It would also be desirable for the improved tooth to be mountable to existing tooth holders. It would also be desirable for the tooth to limit or reduce wobbling within its holder. It would also be desirable to provide a tooth with similar manufacturing costs as those for existing saw teeth.
The present invention concerns a saw tooth for mounting onto a holder of a circular saw or of a mower drum. The tooth comprises a mounting end for mounting against a component of the holder, a cutting end opposite to the mounting end, the cutting end being provided with at least one cutting edge; and a plurality of sides extending from the mounting end to the cutting end. The plurality of sides includes at least one holder side operatively mountable against the holder, and at least one outer side opposite to the holder side. The outer side is non-linear, diverging from the mounting end to the cutting end and having a contour slope which increases from the mounting end to the cutting end. The holder can be either fixed/integral to the disk, or replaceable.
In an embodiment, the outer side of the tooth comprises at least two different diverging segments, the outer side of the tooth being non-linear and diverging out from the mounting end to the cutting end, so as to enable the at least one cutting edge to extend beyond a corresponding mounting edge by at least 0.2 inches, thereby increasing a transversal clearance of the tooth.
In an embodiment, the outer side of the tooth is positioned, shaped and sized so to increase in slope from the mounting end to the cutting end, thereby providing a greater clearance for the tooth at its mounting end, and providing a greater kerf for the tooth at its cutting end.
In an embodiment, the invention concerns a tooth for use with a rotatable circular saw. The tooth is mountable onto a holder of the circular saw, and includes a mounting end for mounting against a component of the holder; a cutting end, opposite to the mounting end, the cutting end being provided with a plurality of cutting edges for cutting applications; and a plurality of sides diverging from the mounting end to the cutting edges of the cutting end. The plurality of sides include at least one holder side mountable against the holder of the circular saw, and at least one outer side opposite to the holder side, the outer side of the tooth being concavely non-linear.
The present invention also concerns an assembly for tree felling applications, the assembly comprising at least one tooth as described above; and at least one holder of a circular saw or mower drum.
The present invention also concerns a circular saw for tree felling applications. The saw includes a rotatable saw disk having an outer periphery, a plurality of tooth holders protruding from said outer periphery; and a plurality of teeth as described above, each of the teeth being mounted onto a respective one of the tooth holders.
Advantageously, the tooth of the present invention provides an increased clearance for the tooth holder while maintaining a short height distance, thus increasing the life of the disk while remaining cost effective.
Other objects, advantages, and features will become more apparent upon reading the following non-restrictive description of the embodiments thereof, given for the purpose of exemplification only, with reference to the accompanying drawings in which:
In the following description, the same numerical references refer to similar elements. The embodiments described in the present description are preferred embodiments only; they are given solely for exemplification purposes.
In addition, it will be appreciated that positional descriptions such as “top”, “bottom”, “side”, “lower”, “upper”, and the like should, unless otherwise indicated, be taken in the context of the figures and should not be considered as limiting or as implying a required orientation during use.
An advantage from the above-discussed tooth according to the present invention is that it substantially increases the kerf and side clearance of the tooth, without having to increase the tooth's height. The proposed tooth also allows keeping the manufacturing costs relatively low, or at least comparable to the manufacturing costs of an existing tooth, since the tooth configuration is simple and does not require an extensive number of machining steps. Another advantage of the tooth is that it is sized and configured so as to be mountable onto existing saw and/or mower drum holders.
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The tooth 10 has a mounting end 12, a cutting end 14 and several sides 18. The mounted end 12 is for mounting against a component 202 of the holder 200. The cutting end 14 is opposite to the mounting end 12, and is provided with at least one cutting edge 16.
The sides 18 extend from the mounting end 12 to the cutting end 14. The tooth 10 includes at least one holder side 18a, which is operatively mountable against the holder 200 and at least one outer side 18c, which is opposite to the holder side 18a. The outer or exposed side 18c is non-linear and diverges from the mounting end 12 to the cutting end 14. The outer side 19c has a contour slope which increases from the mounting end 12 to the cutting end 14.
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As can be appreciated, the tooth 10 constructed according to this first embodiment as a height of 1.79 inch, a kerf of 2.49 inches and a side or transverse clearance of 0.24 inch.
Of course, the dimensions provided are given for the embodiment of the tooth illustrated in the Figures. In other embodiments of the tooth, the dimensions for the base, kerf, length, radius of curvature can vary. For example, in another embodiment, the base of the tooth is about 1.625 inches square and the kerf is about 2.1 inches. Yet in another embodiment, the base is about 2.1 inches and the kerf of about 2.4 inches.
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In the present embodiment, the tooth 10 is symmetrical. The tooth 10 is thus mountable in four different orientations onto the holder 200, by rotating the tooth by about 90 degrees relative to the central axis 44 of the tooth.
In other embodiments, it can be considered to have only the holder side 18a and the outer side 18c as substantially identical. In this case, the tooth 10 would include only two cutting edges, 16a and 16c. Preferably, however the tooth 10 has four cutting edges, 16a-16d, allowing it to be rotated in four different positions. The cutting edge 16c preferably has a V-shape.
It can also be considered to have all cutting edges 16 of the same type. By “same type”, it is meant that the outlines of the edges are identical, as in the embodiments of the tooth 10,110 shown in the Figures. Alternatively, it is possible for the cutting edges to be of different types, for example as described in U.S. Pat. No. 8,061,396. In this case, a first pair of opposed cutting edges can have a linear shape or profile, while the second pair of opposed cutting edges have a curved profile.
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The tooth 10 also has at least one beveled side corner 30c at the intersection of two adjacent sides 18b, 18c. Preferably, the tooth 10 includes four beveled corners 30a-30d. Each beveled side corner 30 includes a corner cutting edge 32. As best show in
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Referring to FIGS. 12 and 15-18, the first segment 120i of the cutting side 118c forms an angle of about 5° with the central axis 144 passing through the tooth 110, while the second segment 120ii forms an angle of about 6.5° with axis 114. In this embodiment of the tooth 110, the cutting side 118c and the holder side 118a are identical, and so the lower portion 119a (identified in
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An advantage of such characteristics of the curved holder side of the tooth is that the mounting of the tooth onto the holder is more resistant to stress and high impacts, and thus the likelihood of the tooth ripping off is reduced. It also increases the size of the “pocket” frontward of the tooth.
Yet another advantage of the non-linear side tooth described above is that it fits existing holders on which standard/straight side teeth can be mounted. Standard dimensions of existing straight side teeth include a 2 inch square base (which can slightly vary depending on manufacturing tolerances/bevelling of edges); a 5° angle on the side of the tooth (and holder seat); a threaded hole for accommodating a 1 inch bolt and a kerf from 2.25 to 2.3125 inches. The improved non-linear side tooth described in the present application not only provides a larger kerf over a standard straight-side tooth, it does so without increasing the stress acting against the disk and/or the corresponding holder, and it remains cost effective, providing more clearance, more tip life (the tips being longer) in a shorter (in terms of height) tooth. Providing the tooth with an increased clearance, while minimizing its height reduces the stress incurred by the rotating disk, which in turn increases the operational life of the disk.
To summarize, and referring to
In other words, the outer side 18c, 118c of the tooth 10, 110 is positioned, shaped and sized so as to increase in slope from the mounting end 12, 112 to the cutting end 14,114, thereby providing a greater clearance tc for the tooth at its mounting end 12, 112, and providing a greater kerf k for the tooth at its cutting end 14,114. Preferably the mounting side is also curved, so as to closely fit an outer surface of a holder and/or circular saw.
The invention also concerns an assembly for tree felling applications, the assembly comprising at least one tooth according to both embodiments 10, 110 described above, and at least one holder 200, 1200, 2200.
The invention also concerns a circular saw comprising a rotatable saw disk having an outer periphery; several tooth holders being either mountable or integral to the outer periphery, and a several teeth as defined above.
As may now be better appreciated, the present invention is an improvement over other related tooth for circular saw or mower drum known in the prior art in that, by virtue of its design, size and configuration, and especially due to its non-linear outer side with diverging segments, the tooth according to the present invention provides a greater kerf and transverse clearance over similar prior art tooth for tree feeling/clearing/brushing applications, while keeping the manufacturing costs reasonable. Providing the holder side of the tooth with a non-linear, and preferably curved or concave profile also allows for a mounting which is more stable and resistant to impacts.
The scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole.
Number | Date | Country | |
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61787318 | Mar 2013 | US |