Patent Application
20180071943
Example embodiments generally relate to hand held power equipment and, more particularly, relate to cutting chain improvements for a chainsaw.
Chainsaws are commonly used in both commercial and private settings to cut timber or perform other rigorous cutting operations. Because chainsaws are typically employed in outdoor environments, and the work they are employed to perform often inherently generates debris, chainsaws are typically relatively robust hand held machines. They can be powered by gasoline engines or electric motors (e.g., via batteries or wired connections) to turn a chain around a guide bar at relatively high speeds. The chain includes cutting teeth that engage lumber or another medium in order to cut the medium as the teeth are passed over a surface of the medium at high speed.
Chainsaws are somewhat notorious for providing a cutting path that can be relatively large as compared to cutting performed by a blade. The cuts performed by a blade tend to be smaller because the blade is thinner than the transverse length of the chain (e.g., the width of the links). Because the chainsaw has a wider cutting path, more wood or other media that is being cut, tends to be removed and lost during the cutting process.
As such, it may be desirable to explore a number of different chain design improvements that could be employed alone or together with other design changes to improve overall chainsaw, and cutting chain, performance.
Some example embodiments may provide for a chainsaw chain constructed with a modification to cutter links to improve cutting properties. The modification to the cutter links of the chain may improve cutting properties to make the chain cut more like a blade than a typical chain. The modification, which involves designing a thin chain, may make the chain have cutting properties that include the removal of less material during cutting. Other improvements may also be possible, and the improvements can be made completely independent of each other, or in combination with each other in any desirable configuration. Accordingly, the operability and utility of the chainsaw may be enhanced or otherwise facilitated.
In an example embodiment, a cutting chain for a chainsaw is provided. The cutting chain may include a plurality of drive links and a plurality of side links. The drive links are arranged to lie in a plane parallel to a plane in which a guide bar about which the chain is rotatable lies. The side links are operably coupled to respective ones of the drive links and are oriented to lie in respective planes substantially parallel to the plane. At least some of the side links include cutting portions. The drive links and side links are attached to each other by rivets, and the rivets have a longitudinal length that is less than or equal to a width of the side links in a transverse direction.
Having thus described some example embodiments in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:
Some example embodiments now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all example embodiments are shown. Indeed, the examples described and pictured herein should not be construed as being limiting as to the scope, applicability or configuration of the present disclosure. Rather, these example embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like reference numerals refer to like elements throughout. Furthermore, as used herein, the term “or” is to be interpreted as a logical operator that results in true whenever one or more of its operands are true. As used herein, operable coupling should be understood to relate to direct or indirect connection that, in either case, enables functional interconnection of components that are operably coupled to each other.
The chainsaw 100 may include a front handle 130 and a rear handle 132. A chain brake and front hand guard 134 may be positioned forward of the front handle 130 to stop the movement of the chain 122 in the event of a kickback. In an example embodiment, the hand guard 134 may be tripped by rotating forward in response to contact with a portion of the arm (e.g., the hand/wrist) of the operator of the chainsaw 100. In some cases, the hand guard 134 may also be tripped in response to detection of inertial measurements indicative of a kickback.
The rear handle 132 may include a trigger 136 to facilitate operation of the power unit when the trigger 136 is actuated. In this regard, for example, when the trigger 136 is actuated (e.g., depressed), the rotating forces generated by the power unit may be coupled to the chain either directly (e.g., for electric motors) or indirectly (e.g., for gasoline engines). The term “trigger,” as used herein, should be understood to represent any actuator that is capable of being operated by a hand or finger of the user. Thus, the trigger 136 may represent a button, switch, or other such component that can be actuated by a hand or portion thereof.
Some power units may employ a clutch to provide operable coupling of the power unit to a sprocket that turns the chain. In some cases (e.g., for a gasoline engine), if the trigger 136 is released, the engine may idle and application of power from the power unit to turn the chain may be stopped. In other cases (e.g., for electric motors), releasing the trigger 136 may secure operation of the power unit. The housing 110 may include a fuel tank for providing fuel to the power unit. The housing 110 may also include or at least partially define an oil reservoir, access to which may be provided to allow the operator to pour oil into the oil reservoir. The oil in the oil reservoir may be used to lubricate the chain as the chain is turned.
As can be appreciated from the description above, actuation of the trigger 136 may initiate movement of the chain around the guide bar 120. A clutch cover 150 may be provided to secure the guide bar 120 to the housing 110 and cover over the clutch and corresponding components that couple the power unit to the chain (e.g., the sprocket and clutch drum). As shown in
In some embodiments, the guide bar 120 may be formed from two laminate core sheets that lie in parallel planes along side each other to define a channel around a periphery of the guide bar 120. The chain (or at least a portion of the chain) may ride in the channel, as the rest of the chain rides along the periphery of the guide bar 120 to engage media for cutting.
For some pairs of side links 220 of the chain 200 one of the side links may be formed as a cutter link 240. Meanwhile, pairs of side links that do not include a cutter link 240 may be referred to as tie links 250. The cutter links 240 may be provided with two portions including a depth gauge portion 260 and a cutting portion 270. The cutting portion 270 may generally engage material that extends beyond the depth of the depth gauge portion 260 when the chain 200 is rotated. Meanwhile, the tie links 250 may not include cutting portions or depth gauge portions and may be provided to simply extend the length of the chain 200 while providing a space between portions of the chain 200 that will create friction during cutting operations. If every side link 210 was a cutter link 240, the friction on the chain 200 would be very high, and it would be difficult to provide sufficient power to turn the chain, and control of the chainsaw 100 could also become difficult. Additionally, if the cutter links 240 were merely allowed to engage large portions of the media to be cut without a restriction on the cutting depth for each cycle, the friction would be high and the run of the chain would be less smooth. Accordingly, the depth gauge portion 260 allows a limit to be placed on the cutting depth or amount of material to be cut with each pass of the cutter link 240.
In a typical chain, such as the one shown in
Given that the rivets 230 extend outside the width of the side links 210 (i.e., in the transverse direction as measured between corresponding outside faces of a pair of the side links 210 in a transverse direction), the amount of protrusion of the rivets 230 determines a minimum amount of overhang that the top plate must have. Accordingly, if the protrusion of the rivets 230 could be avoided, the amount of overhang of the top plate, and correspondingly the overall width of the chain, can be reduced. In order to provide a thinner chain, and perhaps a cut that is more like a cut made by a blade, example embodiments may provide for an improved chain with less width in the transverse direction. This may allow for a smoother, thinner and cleaner cut.
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Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, although the foregoing descriptions and the associated drawings describe exemplary embodiments in the context of certain exemplary combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative embodiments without departing from the scope of the appended claims. In this regard, for example, different combinations of elements and/or functions than those explicitly described above are also contemplated as may be set forth in some of the appended claims. In cases where advantages, benefits or solutions to problems are described herein, it should be appreciated that such advantages, benefits and/or solutions may be applicable to some example embodiments, but not necessarily all example embodiments. Thus, any advantages, benefits or solutions described herein should not be thought of as being critical, required or essential to all embodiments or to that which is claimed herein. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
This application claims priority to U.S. provisional application No. 62/128,176 filed on Mar. 4, 2015, the entire contents of which are incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2016/051190 | 3/2/2016 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62128176 | Mar 2015 | US |
