Patent Publication Number: US-2018036903-A1

Title: Chainsaw chain with modified cutter links

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority to U.S. provisional application No. 62/128,155 filed on Mar. 4, 2015, the entire contents of which are 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 minimize the energy required for executing the cutting procedure. The modification, which involves removing material from an underside of the top plate of the cutter link (and in some cases also involves removal of material on the side plate) may improve stay sharp properties of the chain and provide better out of the box performance. 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. 
    
    
     
       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 in accordance with an example embodiment; 
         FIG. 4 , which includes  FIGS. 4A, 4B, 4C and 4D , illustrates perspective views of a base cutter link ( FIG. 4A ) and various modifications ( FIGS. 4B, 4C and 4D ) that may be made in accordance with an example embodiment; 
         FIG. 5 , which includes  FIGS. 5A, 5B, 5C, 5D and 5E , illustrates perspective views of another base cutter link ( FIG. 5A ) and various modifications ( FIGS. 5B, 5C, 5D and 5E ) that may be made in accordance with an example embodiment; 
         FIG. 6  illustrates a block diagram of a method for modifying a cutter link 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. 
     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 . Regardless of the slope extending away from the side plate  300 , the distance between the top face  316  and the bottom face  314  is generally consistent when moving from the leading edge  312  to the trailing edge along any line that is parallel to the plane in which the base portion  280  lies. 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. To execute a modification of the cutter link  240  in accordance with an example embodiment, stamping, grinding or other processes may be employed to remove material from at least a portion of the bottom face  314  of the top plate  310 .  FIG. 3  illustrates a line  350  approximating a removal line below which material of the bottom face  314  may be removed in accordance with an example embodiment. As can be appreciated from  FIG. 3 , the amount of material removed is greater near the leading edge  312  of the top plate  310 , and decreases as distance from the leading edge  312  increases. In some cases, no material is removed from the bottom face  314  proximate to the trailing edge of the top plate  310 . 
     The removal of material below the removal line  350  may enhance the cutting efficiency and stay sharp properties of the cutter link  240 . In this regard, the removal of some material may reduce friction to obtain better out of box properties. Since there is a slope to the removal line  350 , the top face  316  and the bottom face  314  may no longer have the same distance therebetween when moving from the leading edge  312  to the trailing edge along any line that is parallel to the plane in which the base portion  280  lies. However, the effect of the modification will decrease over time (e.g., as the leading edge  312  retreats due to wear and abrasion). Thus, the slope eventually ends near the end of life. As such, the distance between the top face  316  and the bottom face  314  at the leading edge  312  may increase over time. 
     In some embodiments, the modification of the cutter link  240  may involve removal of at least a portion of the bottom face  314  of the top plate  310  and a portion of the inside face  304  of the side plate  300 . This further modification is illustrated in reference to  FIGS. 4 and 5 . 
     As shown in  FIG. 4 , a base model cutter link is shown in  FIG. 4A  and may initially be formed to have a side plate  400  with a leading edge  402  and inside face  404 . The cutter link may also have a top plate  410  having a leading edge  412  and a bottom face  414 . The leading edge of  412  of the top plate  410  may extend substantially perpendicularly with respect to the leading edge  402  of the side plate  400 , and the inside face  404  may meet the bottom face  414  at an interface portion  420  that may be curved. As mentioned above, material may be removed from the bottom face  414  (e.g., by grinding) such that the amount of material removed decreases as distance from the leading edge  412  of the top plate  410  increases. In each of  FIGS. 4B, 4C and 4D , the slope of the removal line is substantially similar. However, the amount of material removed from the inside face  404  of the side plate  400  is different in  FIGS. 4B, 4C and 4D . In this regard,  FIG. 4D  does not include any material removed from the side plate  400 . Thus, material is only removed from the bottom face  414 . In  FIG. 4C , some material is removed also from the inside face  404 , and the amount of material removed decreases as distance from the leading edge  402  of the side plate  400  increases. In  FIG. 4B , even more material is removed from the inside face  404 . However, the amount of material still generally decreases as distance from the leading edge  402  of the side plate  400  increases. 
       FIG. 5  illustrates a similar example with a different base model. Again, the base model cutter link shown in  FIG. 5A  is initially formed to have a side plate  500  with a leading edge  502  and inside face  504 . The cutter link may also have a top plate  510  having a leading edge  512  and a bottom face  514 . A difference between the base models of  FIGS. 4 and 5  is that the top plate  510  tapers more on the example of  FIG. 5  as the top plate  510  extends away from its interface with the side plate  500 . 
     In this example as well, the leading edge of  512  of the top plate  510  may extend substantially perpendicularly with respect to the leading edge  502  of the side plate  500 , and the inside face  504  may meet the bottom face  514  at an interface portion  520  that may be curved. As mentioned above, material may be removed from the bottom face  514  (e.g., by grinding) such that the amount of material removed decreases as distance from the leading edge  512  of the top plate  510  increases. In each of  FIGS. 5B, 5C and 5D , the slope of the removal line is substantially similar. However, the amount of material removed from the inside face  504  of the side plate  500  is different in  FIGS. 5B, 5C and 5D . In this regard,  FIG. 5D  does not include any material removed from the side plate  500 . Thus, material is only removed from the bottom face  514 . In  FIG. 5C , some material is removed also from the inside face  504 , and the amount of material removed decreases as distance from the leading edge  502  of the side plate  500  increases. In  FIG. 5B , even more material is removed from the inside face  504 . However, the amount of material still generally decreases as distance from the leading edge  502  of the side plate  500  increases.  FIG. 5E  illustrates another example in which material is removed from both the side plate  500  and the top plate  510  to form a cutter link trench  580  that extends from the top plate  510  downward toward the base portion  280 . Moreover, as shown in  FIG. 5E , a depth gauge  590  may extend upward from the base portion  280  in front of the gap  290  by an amount sufficient to have a top of the depth gauge end in between the top and bottom of the cutter link trench  580 . 
       FIG. 6  illustrates a block diagram of a method of modifying a cutter link of cutting chain for a chainsaw. The method may include forming the cutter link to include a base portion and a cutting portion extending away from the base portion at operation  600 . The cutting portion may include a side plate and a top plate. The top plate may include a top plate leading edge and a bottom face. The side plate may include a side plate leading edge and an inside face. The method may further include removing at least a portion of material forming the bottom face at operation  610 . The portion of material forming the bottom face that is removed decreases as distance from the top plate leading edge increases. In some cases, the method may further (and optionally) include removing at least a portion of the inside face at operation  620 . The portion of the inside face that is removed may decrease as distance from the side plate leading edge increases. The top plate may further include a top face that is opposite the bottom face. A distance between the bottom face and the top face may increase as distance from the top plate leading edge increases. In some cases, the removal of at least the portion of material forming the bottom face may be accomplished via grinding. 
     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.