WO2016139569A1

WO2016139569A1 - Chainsaw chain design for cutting and planing in two steps

Info

Publication number: WO2016139569A1
Application number: PCT/IB2016/051113
Authority: WO
Inventors: Hasse Lilja; Niklas SARIUS; Hans-Åke SUNDBERG; Johan MILLENBERG; Jonatan GUNÉR; Adam STÅHLKRANTZ; Per CARLBÄCK; Richard Hall
Original assignee: Husqvarna AB
Current assignee: Husqvarna AB
Priority date: 2015-03-04
Filing date: 2016-02-29
Publication date: 2016-09-09
Anticipated expiration: 2017-09-04

Abstract

A cutting chain (500) for a chainsaw (100) may include a plurality of drive links (540), a plurality of side links (520/530) operably coupled to respective ones of the drive links (540), a slicer element (430/440) and a planing element (445). The drive links (540) extend in a first direction substantially parallel to sides of a guide bar (120) about which the cutting chain (500) is rotatable. The side links (520/530) are operably coupled to respective ones of the drive links (540) and are oriented to lie in planes substantially parallel to the first direction. At least some of the side links (520/530) are cutter links (400). The slicer element (430/440) extends parallel to the first direction to cut a chip in media to be cut responsive to rotation of the cutting chain (500). The planing element (445) is disposed after the slicing element (430/440) in the cutting chain (500) and extends in a direction substantially perpendicular to the first direction to remove the chip cut by the slicer element (430/440).

Description

CHAINSAW CHAIN DESIGN FOR CUTTING AND PLANING IN TWO STEPS

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. provisional application numbers 62/128,213, 62/128,147, 62/128,226 and 62/128,140 all filed on March 4, 2015, the entire contents of which are hereby incorporated herein by reference.

TECHNICAL FIELD

Example embodiments generally relate to hand held power equipment and, more particularly, relate to cutting chain improvements for a chainsaw.

BACKGROUND

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.

Given that the chainsaw may be employed to cut media of various sizes and types, it should be appreciated that the design of the chain itself may have an impact on the effectiveness of the cutting operations. 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.

BRIEF SUMMARY OF SOME EXAMPLES

Some example embodiments may provide for a chainsaw chain constructed with a modification to cutter links to improve cutting efficiency. The modification to the cutter links of the chain may improve cutting efficiency and reduce the energy required for executing the cutting procedure, and also minimize the effects of normal wear on cutting efficiency. The modification, which involves designing the cutter links to cut sides of a chip in a first step and then perform a planing action in a second step, may make the cutter links have cutting efficiencies that are increased. The cutter links may therefore have better performance over a longer useful life.

In such an example, a cutting chain for a chainsaw may be provided. The cutting chain may include a plurality of drive links, a plurality of side links operably coupled to respective ones of the drive links, a slicer element and a planing element. The drive links extend in a first direction substantially parallel to sides of a guide bar about which the chain is rotatable. The side links are operably coupled to respective ones of the drive links and are oriented to lie in planes substantially parallel to the first direction. At least some of the side links are cutter links. The slicer element extends parallel to the first direction to cut a chip in media to be cut responsive to rotation of the chain. The planing element is disposed after the slicing element in the chain and extends in a direction substantially perpendicular to the first direction to remove the chip cut by the slicer element.

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.

For example, 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 close fitting cutter links, tie straps, bumpers and drive links that minimize out of plane extension of components, may make the chain have cutting properties that are sharper for straight ahead cutting. In such an example, a cutting chain for a chainsaw may be provided. The cutting chain may include a plurality of drive links and a plurality of side links. The drive links extend in a first direction substantially parallel to sides of a guide bar about which the chain is rotatable. The side links are operably coupled to respective ones of the drive links and are oriented to lie in planes substantially parallel to the first direction. At least some of the side links include grinding elements and at least some others of the side links include bumpers. The drive links include grinding elements disposed proximate to the grinding elements of the side links, and each pair of adjacent grinding elements is preceded by a bumper.

In some embodiments, the modification to the cutter links of the chain may improve cutting efficiency and reduce the energy required for executing the cutting procedure, and also minimize the effects of normal wear on cutting efficiency. The modification, which involves designing the cutter links to be unsymmetrical relative to each other, but instead for each cutter link to cut on both sides, may improve cutter link efficiency. The cutter links may therefore have better performance over a longer useful life. In such an example, a cutting chain for a chainsaw may be provided. The cutting chain may include a plurality of drive links and a plurality of side links operably coupled to respective ones of the drive links via rivets that extend in a transverse direction. At least some of the side links include cutter links. At least one of the cutter links includes a base portion, a cutting portion and a depth gauge portion. The cutting portion extends away from the base portion and includes a side plate and a top plate. The top plate has a width in the transverse direction that is at least longer than a length of the rivets. The depth gauge portion extends away from the base portion in the same direction as the cutting portion.

In other example embodiments, the modification may involve designing the cutter links to split the media being cut into smaller chips that can be more easily transported away, may make the cutter links have cutting efficiencies that are increased. The cutter links may therefore have better stay sharp properties and a longer useful life. In such an example, a cutting chain for a chainsaw may be provided. The cutting chain may include a plurality of drive links and a plurality of cutter links operably coupled to respective ones of the drive links. At least one of the cutter links may include a base portion, a cutting portion extending away from the base portion, and a depth gauge portion. The cutting portion may include a side plate and a top plate. The depth gauge portion may extend away from the base portion in the same direction as the cutting portion. At least another one of the side links or one of the drive links includes a cutter element positioned in front of the cutting portion of a next cutter link. The cutter element is configured to generate a chip for removal by the cutter link.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S) 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:

FIG. 1 illustrates a side view of a chainsaw according to an example embodiment;

FIG. 2 illustrates a side view of a chainsaw guide bar employing a chain according to an example embodiment;

FIG. 3 illustrates a perspective side view of one cutter link;

FIG. 4 illustrates a perspective side view of a cutter link employing a two step cutting and planing process in accordance with an example embodiment;

FIG. 5 illustrates a side view of a chain including a cutter link employing a two step cutting and planing process in accordance with an example embodiment; FIG. 6 illustrates a perspective side view of a chain employing a two step cutting and planing process with separate links performing respective functions in accordance with an example embodiment;

FIG. 7 illustrates a front view of the chain of FIG. 6 in accordance with an example embodiment;

FIG. 8 illustrates a perspective side view of a cutter link capable of splitting chips for better chip transportation in accordance with an example embodiment;

FIG. 9 illustrates a perspective side view of a chain employing cutter links of an example embodiment;

FIG. 10 illustrates a perspective side view of an unsymmetrical cutter link according to an example embodiment;

FIG. 11 illustrates a perspective side view of an alternative unsymmetrical cutter link in accordance with an example embodiment;

FIG. 12 illustrates a perspective side view of a chain design in accordance with an example embodiment;

FIG. 13 illustrates a front view of the chain of FIG. 12 in accordance with an example embodiment; and

FIG. 14 illustrates a side view of a chain design in accordance with an example embodiment.

DETAILED DESCRIPTION

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.

FIG. 1 illustrates side view of a chainsaw 100 according to an example embodiment. As shown in FIG. 1, the chainsaw 100 may include a housing 110 inside which a power unit or motor (not shown) is housed. In some embodiments, the power unit may be either an electric motor or an internal combustion engine. Furthermore, in some embodiments, the power unit may include more than one electric motor where one such electric motor powers the working assembly of the chainsaw 100 and the other electric motor of the power unit powers a pump that lubricates the working assembly or provides momentum for moving other working fluids within the chainsaw 100. The chainsaw 100 may further include a guide bar 120 that is attached to the housing 110 along one side thereof. A chain (not shown) may be driven around the guide bar 120 responsive to operation of the power unit in order to enable the chainsaw 100 to cut lumber or other materials. The guide bar 120 and the chain may form the working assembly of the chainsaw 100. As such, the power unit may be operably coupled to the working assembly to turn the chain around the guide bar 120.

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 FIG. 1, the clutch cover 150 may be attached to the body of the chainsaw 100 (e.g., the housing 110) via nuts 152 that may be attached to studs that pass through a portion of the guide bar 120. The guide bar 120 may also be secured with the tightening of the nuts 152, and a tightness of the chain can be adjusted based on movement of the guide bar 120 and subsequent tightening of the nuts 152 when the desired chain tightness is achieved. However, other mechanisms for attachment of the clutch cover 150 and/or the guide bar 120 may be provided in other embodiments including, for example, some tightening mechanisms that may combine to tighten the chain in connection with clamping the guide bar 120.

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. FIG. 2 illustrates a typical chain 200 disposed on the guide bar 120. The chain 200 includes a plurality of center drive links 210 that each include a portion thereof that rides in the channel. Each center drive link 210 is attached to an adjacent pair of side links 220 by rivets 230 that extend perpendicular to the longitudinal length of the links. A rivet 230 is provided at the front portion of each center drive link 210 to attach the center drive link 210 to the rear portion of a preceding side links 220 and another rivet 230 is provided at the rear portion of each center drive link 210 to attach the center drive link 210 to the front portion of a subsequent side links 220. As such, each pair of side links 220 connects to opposing sides of the center drive links 210, and the connections are repeated in alternating fashion to complete a circular or endless chain.

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 FIG. 2, cutter links 240 are provided alternating on right and left sides of the chain. Moreover, left side cutter links and right side cutter links are generally symmetrical to provide for a smooth cut that makes a cutting path through the media being cut (e.g., wood) that is at least wider than the rivets 250 or, otherwise the widest part of the chain. In doing so, the left side cutters cut along the left side of the cutting path, and the right side cutters symmetrically cut along the right side of the cutting path. As such, the cutting done on opposing sides of the cutting path is performed sequentially via the symmetrical left and right side cutters engaging the wood.

As shown in FIG. 3, the cutter links 240 may have a base portion 280 from which both the cutting portion 270 and the depth gauge portion 260 extend. The rivets may be passed through holes in the base portion 280. The cutting portion 270 may extend away from the base portion 280 in the same direction that the depth gauge portion 260 extends away from the base portion 280. However, the depth gauge portion 260 may be at one end of the cutter link 240 and the cutting portion 270 may be at the other end, separated from each other by a gap 290. Of note, the gap 290 may grow in size over time, as the cutting portion 270 is worn or abraded away due to use.

The cutting portion 270 may include a side plate 300 that extends upward away from the base portion 280. Although the side plate 300 generally extends in a direction parallel to plane in which the base portion 280 lies, the side plate 300 does not necessarily also lie in the same plane. In some cases, the side plate 300 may have a curved shape to bend slightly out of the plane. Moreover, in some embodiments, the side plate 300 may bend out of the plane and then back toward the plane as it extends away from the base portion 280. Regardless, the distal end of the side plate 300 may be joined with a top plate 310. The top plate 310 may lie in a plane that is substantially perpendicular to the plane in which the base portion 280 lies.

The side plate 300 may have a leading edge 302 and an inside face 304. The side plate may also have an outside face that is opposite the inside face 304, and a trailing edge that is opposite the leading edge 302. The top plate 310 may have a leading edge 312 that extends substantially perpendicular to the direction of extension of the base 280 (and in some cases also the direction of extension of the leading edge 302 of the side plate 300). The top plate 310 may also have a bottom face 314 and a top face 316. The top face 316 may be opposite the bottom face 314 and, in some cases, the top and bottom faces 316 and 314 may be in parallel planes. However, in some cases, the top and bottom faces 316 and 314 may be angled slightly toward each other as they extend away from the side plate 300. The top plate 310 may also have a trailing edge disposed opposite the leading edge 312.

In an example embodiment, the cutter link 240 may be formed by stamping, grinding and combinations thereof with or without other techniques also being employed. In a typical situation, the elevation difference between the depth gauge portion 260 and the cutting portion 270 of the cutter link 240 defines a cutting depth for the cutter link 240. The depth gauge portion 260 therefore generally has a relatively blunt leading edge and does little to grind on the material being cut. Instead, the leading edge 312 of the top plate 310 and the leading edge 302 of the side plate 300 may combine to grind and shear or plane the media being cut to generate chips and shavings while cutting a path through the media. In particular, the side plate 300 may cut simultaneously with the planing action performed by the top plate 310. As such, the cutting and planing operations are all done in a single step.

To improve the ability of cutter links to effectively and efficiently remove media chips, an example embodiment may be provided to cut fibers (e.g., via a slicing action) prior to the planing operations being engaged. In other words, an example embodiment is provided to perform cutting and planing in two separate steps that are performed in sequence on a particular portion of the media being cut. Although the separate operations can be performed by one cutter link or multiple links in sequence, it should be appreciated that separate structures are provided in sequence (on one link or multiple links) to perform the cutting and planing operations in distinct steps rather than simultaneously. This may result in slicing done in the first step to liberate (or form) chips that can then more easily be planed off for removal. The two step cutting and planing operation may be more efficient.

FIG. 4 illustrates an example embodiment in which a two stage cutting element 400 is provided to span across (and therefore include) two side links. As shown in FIG. 4, the two stage cutting element 400 is provided to span across opposing sides of the drive links before and after the two stage cutting element 400. As such, the two stage cutting element 400 includes two base portions (e.g., first base portion 410 and second base portion 420). The first and second base portions 410 and 420 may include respective first and second slicer elements 430 and 440 that extend away from the first and second base portions 410 and 420, respectively, at a front end of the two stage cutting element 400. The first and second slicer elements 430 and 440 may, at least in part, serve as depth gauges to define a cutting depth (or planing depth) for a planing portion 442, which follows the first and second slicer elements 430 and 440. However, the first and second slicer elements 430 and 440 may also function to slice the media being cut and form chips that can then be removed by the planing element 445 that forms the planing portion 442. As such, unlike a typical depth gauge, which is blunt, the first and second slicer elements 430 and 440 may each be sharpened at their respective distal ends to form a blade oriented forward (relative to the cutting direction) to slice media encountered during rotation of the chain. The slicing action occurs along a direction parallel to the sides of the guide bar on which the chain rotates.

The planing element 445 of this example links the first and second base portions 410 and 420 by spanning from a first side plate 450 to a second side plate 460 via a top plate 470. The first and second side plates 450 and 460 may extend upward and away from the first and second base portions 410 and 420, respectively, similar to the direction and way that the first and second slicer elements 430 and 440. The top plate 470 then spans across and joins distal ends of the first and second side plates 450 and 460. As shown in FIG. 4, the top plate 470 may define a leading edge that is arcuate in shape extending between opposing side limits of the top plate 470. An apex of the arcuate shape of the leading edge may be substantially in alignment with the drive links to which the two stage cutting element 400 attaches. The planing element 445 may cut along a plane that is substantially perpendicular to the plane in which the slicing action of the slicer elements occurs.

When employed in a chain 500, as shown in FIG. 5, the two stage cutting element 400 may be moved in the direction 510 and a cutting portion 405 (formed by the first and second slicer elements 430 and 440) may slice the media being cut to form chips that can then be removed by the planing element 445 of the planing portion 442 in a separate step. As shown in FIG. 5, the chain 500 may include other side links 520 and 530, which may be bumpers or tie straps. The other side links 520 and 530 may be operably coupled to the two stage cutting element 400 via drive links 540, and it should be appreciated that the initial cutting function could be performed at any of the other side links 520 and 530 instead of being performed all on one link. FIG. 6 illustrates such an example.

As shown in FIG. 6, a chain 600 may be provided to include a slicing link 610 that is configured to perform a slicing action similar to either of the first and second slicer elements 430 and 440. The slicing link 610 may be provided in the chain 600 prior to the placement of a planing link 620. FIG. 7 shows a front view of the arrangement. As can be appreciated from FIGS. 6 and 7, the slicing link 610 initially performs a slicing or cutting action to form a chip, and then the planing link 620 performs a planing action to remove the chip. As such, the wood or other media is initially cut at its sides by the slicing action of the slicing link 610, and then removed by the planing action of the planing link 620. Example embodiments may therefore provide a chain that performs cutting (or slicing) operations and planing operations in separate steps, with separate, sequentially ordered structures on the chain.

As mentioned above, the ability of the cutting portion 270 to effectively and efficiently remove media chips may be improved, for example, by cutting fibers (e.g., via a slicing action) prior to the cutting portion 270 being engaged. FIG. 8 illustrates an example embodiment in which a cutting element 640 is provided on a side link (e.g., a tie strap 650) that is paired with the cutter link 240. As shown in FIG. 8, the cutting element 640 is provided on the opposite side relative to the side of the drive link on which the side plate 300 is provided. Thus, the cutting element 640 may slice the media (or fiber) to free or create a chip that can then be more efficiently removed by the top plate 310 of the cutter link 240. In this example, since the cutting element 640 is paired with the cutter link 240, the cutting element 640 must be at the leading edge of the side link on which it is provided. However, if the cutting element is not paired with cutter link 240, then there is no requirement for the cutting element to be at the leading edge. FIG. 9 illustrates such an example.

As shown in FIG. 9, a cutting element 660 is provided at a trailing end of a side link, but is provided earlier in the order of links of the chain than the cutter links 240. Accordingly, the cutting element 660 may create a chip that can be more efficiently removed or transported by the cutter links 240. In the example of FIG. 9, the cutter links are divided into pairs and one pair has the function of precutting the wood to ensure that chips will be generated after each cutter link and therefore increase cutting efficiency and chip transportation. Example embodiments may cut the media (e.g., wood) initially with a slicing action to create a chip, and then allow the freed chip to be more easily removed by the cutter links 240. Creating smaller wood chips would require less energy to transport the smaller chips away and therefore result in a higher cutting efficiency.

Generally speaking, the cutting elements that perform the slicing action to create smaller chips can be on the side link paired with the cutter link 240 (if placed at the leading edge of the side link), or may be placed on any part of a drive link or other side link that precedes the cutter link 240 in the ordering of links in the chain. In a typical chain, such as the one shown in FIG. 2, cutter links 240 are provided alternating on right and left sides of the chain. Moreover, left side cutter links and right side cutter links are generally symmetrical to provide for a smooth cut that makes a cutting path through the media being cut (e.g., wood) that is at least wider than the rivets 250 or, otherwise the widest part of the chain. In doing so, the left side cutters cut along the left side of the cutting path, and the right side cutters symmetrically cut along the right side of the cutting path. As such, the cutting done on opposing sides of the cutting path is performed sequentially via the symmetrical left and right side cutters engaging the wood.

As shown in FIGS. 10 and 11, an unsymmetrical cutter link 700 may be provided to cut both left and right sides of the cutting path simultaneously. As such, although it may still be desirable to provide left side and right side cutters, it is not necessary since either only left side cutters or only right side cutters employing the unsymmetrical cutter link 700 would be capable of cutting the full width of the cutting path alone. Like the cutter links 240 above, the unsymmetrical cutter link 700 may have a base portion 710 from which both a depth gauge portion 720 and a cutting portion 730 extend substantially perpendicular to the direction of chain extension (and movement).

The unsymmetrical cutter link 700 may be provided as one side link, and thus rivet holes may be provided through the base portion 710. The rivets may be passed through the rivet holes in the base portion 710 to engage adjacent drive links and a tie strap or other side link that is paired with the unsymmetrical cutter link 700 on the opposing side of the drive links. As such, the rivets should be understood to pass through the base portion 710 in a transverse direction. Although not required, the rivets may extend transversely through, and slightly beyond the outer faces of the base portion 710 and any tie strap or other side link that is paired with the unsymmetrical cutter link 700. As such, the length of the rivets may define a minimum width that the cutting path must form in the wood or other media being cut.

As shown in FIGS. 10 and 11, the cutting portion 730 may include a top plate 740 and a side plate 750. In some cases, both the top plate 740 and the side plate 750 may have sharpened leading edges to allow the top plate 740 and the side plate 750 to more efficiently cut and/or grind on the media to be cut. In some embodiments, a leading edge of the top plate 740 may be formed to have an arcuate shape that extends from a first side limit 760 to a second side limit 770. The first and second side limits 760 and 770 may represent the forward most portions of the top plate 740, and the leading edge of the top plate 740 may recess toward a rear of the cutting portion 730 to an apex 780. A distance between the first and second side limits 760 and 770 may define the cutting path width 795. Moreover, as indicated above, the cutting path width 795 may be at least greater than the length of the rivets. As such, it can be appreciated that the apex 780 of every cutter link on the chain (when all cutter links are unsymmetrical cutter links 700) may be substantially in a same plane with the drive links and therefore approximately in a center of the cutting path (i.e., a midpoint of the cutting path width). The first and second side limits 760 and 770 therefore span entirely across the width of the base portion 710, the drive link and the tie strap or other side link that is paired with the unsymmetrical cutter link 700 in the transverse direction. Moreover, the first and second side limits 760 and 770 may extend beyond respective opposing longitudinal ends of the rivets.

Although the side plate 750 generally extends upward away from the base portion 710

(e.g., in a direction parallel to plane in which the base portion 710 lies), the side plate 750 does not necessarily also lie in the same plane. In this regard, for example, the side plate 750 may have a curved shape to bend slightly out of the plane in the opposite direction from the direction of extension of the top plate 740. Regardless, the distal end of the side plate 750 may be joined with a top plate 740 and the top plate 740 may generally lie in a plane that is substantially perpendicular to the plane in which the base portion 710 lies. However, in some cases, the top plate 740 may be slightly curved to present a convex shape upward and a concave shape downward. Meanwhile in other cases, the top plate 740 may be substantially flat.

In an example embodiment, the unsymmetrical cutter link 700 may be formed by stamping, grinding and combinations thereof with or without other techniques also being employed. In a typical situation, the elevation difference between the depth gauge portion 720 and the cutting portion 730 of the unsymmetrical cutter link 700 defines a cutting depth for the unsymmetrical cutter link 700. The depth gauge portion 720 therefore generally has a relatively blunt leading edge and does little to grind on the material being cut. Instead, the leading edge of the top plate 740 as defined by the first and second side limits 760 and 770 and the apex 780 may combine to grind and shear or plane the media being cut to generate chips and shavings while creating the cutting path through the media. However, unlike a typical chainsaw blade, the cutting path width is defined by a single cutter link (i.e., the width of the top plate 740 of the unsymmetrical cutter link 700).

Thus, by employing the unsymmetrical cutter link 700, both sides of the cutting path are cut simultaneously. As such, a single cutter link (i.e., the unsymmetrical cutter link 700) performs the job that two cutter links perform in a conventional chain. Cutting forces exerted in the transverse direction (i.e., sideways) will also cancel each other out for the unsymmetrical cutter link 700, unlike a conventional chain. Accordingly, the elimination of transverse direction forces may result in less sideways drift of the cutter links, which may provide a more consistent cutting width along the cutting path. Thus, a higher cutting efficiency can be achieved.

As discussed above in reference to FIG. 2, in a typical chain, cutter links 240 are provided alternating on right and left sides of the chain. Moreover, left side cutter links and right side cutter links are generally symmetrical to provide for a smooth cut that makes a cutting path through the media being cut (e.g., wood) that is at least wider than the rivets 250 or, otherwise the widest part of the chain. The cutter links also have a top plate that extends out of the plane in which the side links generally lie. Accordingly, the cutter links tend to be susceptible to side forces that create instability and sideways drift that result in a rough cut. In order to provide a smoother cut, and perhaps a cut that is more like a cut made by a blade, example embodiments may provide for an improved chain with fewer portions or elements that extend out of plane. This may allow for a smoother and cleaner cut. FIGS. 12-14 illustrate an example of such an improved chain.

As shown in FIGS. 12-14, and particularly in FIG. 13, which shows a front view, the chain 800 of an example embodiment may have a relatively tight construction and thin profile along the transverse direction. In this regard, each of the drive links 810 may have a grinding element 812 extending away from a base portion 814 thereof. The grinding elements 812 of the drive links 810 may be disposed at a rear portion of each respective one of the drive links 810. Meanwhile the side links 820 may include bumper elements 830 and/or grinding elements 840 that extend away from base portions 850 thereof. The base portions 850 of the side links 820 and the base portions 814 of the drive links 810 may each lie in planes that are parallel to each other. The base portions 850 of the side links 820 and the base portions 814 of the drive links 810 may also be adjacent to each other in the following order: right base portion of side link, base portion of drive link, left base portion of side link. The side links 820 and drive links 810 may be operably coupled to each other via rivets 860 that pass through rivet holes 865 provided therein. Thus, the side links 820 and drive links 810 may fit together fairly closely.

As shown in FIGS. 12 and 14, the bumper elements 830 may be provided at rear portions of the side links 820 and may be slanted away from the direction of chain motion (shown by arrow 870). Meanwhile, the grinding elements 840 of the side links 820 may be provided generally at a front end of the corresponding side links 820. Moreover, the grinding elements 840 of the side links 820 and the grinding elements 814 of the drive links 810 may be placed substantially side by side with each other (when traversing straight portions of the guide bar 120). The grinding elements 840 of the side links 820 and the grinding elements 814 of the drive links 810 may also have similar shapes and sizes (however, the grinding elements 814 of the drive links 810 may be slightly smaller). Placement of the grinding elements 840 of the side links 820 and the grinding elements 814 of the drive links 810 next to each other, and with similar sizes and shapes may allow these elements to mutually reinforce each other to maintain the entire chain less susceptible to sideways drift.

As shown in FIGS. 12 and 14, the bumper element 830 may act as a depth gauge to limit the exposure of the grinding elements 840 and 814. As such, a bumper element 830 precedes each pair of grinding elements 840 and 814. Moreover, bumper elements 830 are on alternate sides, as are the grinding elements 840 and 814, with respect to the sequence of links in the chain 800. Accordingly, in this example, a side link may have right side grinding elements and a left side bumper. The next side link (or at least the next side link with grinding elements) may then alternate to having left side grinding elements and a right side bumper. The combination of a compact and reinforcing structure with alternating bumpers and grinding elements may create a smoother run by preventing the grinding elements 840 and 814 from taking too much wood on any one pass. The smoother run also allows the chain 800 to cut more like a blade.

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.

Claims

1. A cutting chain (500) for a chainsaw (100), the cutting chain (500) comprising:

a plurality of drive links (540) extending in a first direction substantially parallel to sides of a guide bar (120) about which the cutting chain (500) is rotatable; and

a plurality of side links (520/530) operably coupled to respective ones of the drive links (540) and oriented to lie in planes substantially parallel to the first direction, at least some of the side links (520/530) comprising cutter links (400);

a sheer element (430/440) extending parallel to the first direction to cut a chip in media to be cut responsive to rotation of the cutting chain (500); and

a planing element (445) disposed after the sheer element (430/440) in the cutting chain (500), the planing element (445) extending in a direction substantially perpendicular to the first direction to remove the chip cut by the sheer element (430/440).

2. The cutting chain (500) of claim 1, wherein the cutter links (400) include both the sheer element (430/440) at a cutting portion (405) of the cutter links (400) and the planing element (445) at a planing portion (442) of the cutter links (400).

3. The cutting chain (500) of claim 2, wherein the planing element (445) comprises a top plate (470) that spans transversely across the planing portion (442) between first and second side plates (450 and 460) of the planing portion (442).

4. The cutting chain (500) of claim 3, wherein the sheer element (430/440) comprises a first sheer element (430) forward of the first side plate (450) and a second sheer element (440) forward of the second side plate (460).

5. The cutting chain (500) of claim 3, wherein the top plate (470) comprises a leading edge having an arcuate shape, and an apex of the arcuate shape is in a plane with the drive links (540).

6. The cutting chain (500) of claim 1, wherein the cutter links (400) comprise the planing element (445), and the sheer element (430/440) is provided at another side link (520) of the cutting chain (500) preceding the planing element (445).

7. A cutting chain (500) for a chainsaw, the cutting chain (500) comprising: a plurality of drive links (540); and

a plurality of side links (520/530) operably coupled to respective ones of the drive links (540), at least some of the side links (520/530) comprising cutter links (240),

wherein at least one of the cutter links (240) comprises:

a base portion (280);

a cutting portion (270) extending away from the base portion (280), the cutting portion (270) including a side plate (300) and a top plate (310); and

a depth gauge portion (260) extending away from the base portion (280) in the same direction as the cutting portion (270),

wherein at least another one of the side links (650) or one of the drive links includes a cutter element (640) positioned in front of the cutting portion of a next cutter link, the cutter element (640) being configured to generate a chip for removal by the next cutter link.

8. The cutting chain (500) of claim 7, wherein the at least another one of the side links (650) comprises a tie strap paired with the at least one of the cutter links.

9. The cutting chain (500) of claim 8, wherein the cutting element (640) is disposed at a leading edge of the tie strap.

10. The cutting chain (500) of claim 7, wherein the at least another one of the side links (650) comprises a tie strap preceding the at least one of the cutter links.

11. A cutting chain (500) for a chainsaw, the cutting chain (500) comprising: a plurality of drive links (540); and

a plurality of side links (520/530) operably coupled to respective ones of the drive links (540) via rivets that extend in a transverse direction, at least some of the side links (520/530) comprising cutter links (700),

wherein at least one of the cutter links (700) comprises:

a base portion (710);

a cutting portion (730) extending away from the base portion (710), the cutting portion(730) including a side plate (750) and a top plate (740); and a depth gauge portion (720) extending away from the base portion (710) in the same direction as the cutting portion (730),

wherein the top plate has a width (795) in the transverse direction that is at least longer than a length of the rivets.

12. The cutting chain (500) of claim 11, wherein a leading edge of the top plate comprises a first side limit (760) and a second side limit (770) that define the width (795) of the top plate (740), and wherein the first and second side limits (760 and 770) extend beyond respective opposing longitudinal ends of the rivets.

13. The cutting chain (500) of claim 12, wherein the first and second side limits (760 and 770) define forward most portions of the leading edge of the top plate (740), and wherein the leading edge of the top plate (740) has an arcuate shape extending rearward to an apex (780).

14. The cutting chain (500) of claim 13, wherein the apex (780) is substantially in alignment with the drive links (540).

15. The cutting chain (500) of claim 13, wherein apexes (780) of each of the cutter links (700) in the cutting chain (500) are in alignment and lie in a same plane with the drive links (540).

16. The cutting chain (500) of claim 11, wherein the side plate (750) curves out of a plane in which the base portion (710) lies in a direction opposite the direction of extension of the top plate (740) from an intersection of the top plate (740) with the side plate (750).

17. A cutting chain (800) for a chainsaw (100), the cutting chain (800)

comprising:

a plurality of drive links (810) extending in a first direction substantially parallel to sides of a guide bar (120) about which the cutting chain (800) is rotatable; and

a plurality of side links (820) operably coupled to respective ones of the drive links (810) and oriented to lie in planes substantially parallel to the first direction, at least some of the side links (820) comprising grinding elements (840) and at least some others of the side links (820) comprising bumpers (830), wherein the drive links include grinding elements (812) disposed proximate to the grinding elements (840) of the side links (820), and each pair of adjacent grinding elements (840/812) is preceded by one of the bumpers (830).

18. The cutting chain (800) of claim 17, wherein a bumper (830) preceding each pair of adjacent grinding elements (840/812) is located on the same side as the corresponding pair of adjacent grinding elements (840/812).

19. The cutting chain (800) of claim 18, wherein the grinding elements (840) of the side links (820) are similar in size and shape to the grinding elements (812) of the drive links (810).

20. The cutting chain (800) of claim 18, wherein pairs of adjacent grinding elements (840/812) are sequentially provided on opposite transverse sides of the cutting chain (800).