TECHNICAL FIELD

[0001 ] Example embodiments generally relate to hand held power equipment and, more particularly, relate to a coast brake mechanism for a chainsaw.

BACKGROUND

[0002] 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 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.

[0003] Given that the chain is expected to turn at relatively high speeds, and that the teeth are designed to cut, it can be appreciated that the chain should not be allowed to come into contact with any material that is not specifically intended for cutting while the chain is rotating around the bar. Certain phenomena such as kickback can create conditions in which the chances of inadvertent contact with a rotating chain could occur. Accordingly, many chainsaws are designed to include a chainbrake activated by a hand guard that is placed proximate to a forward hand of the operator (i.e., the hand closest to the chain during operation) in order to stop operation of the chainsaw (and rotation of the chain) if a kickback occurs. In this regard, for example, if the chainbrake is activated when hand guard is actuated responsive to contact with a hand or inertia generated by a kickback, the rotation of the chain may be quickly stopped.

[0004] One way to stop chain rotation is to remove the motive force applied to the chain. Thus, a switch may be used to stop a power source from turning the chain. It can be appreciated that it is desirable to stop the chain from rotating relatively quickly, however, simply stopping the application of power to the engine or motor may not be sufficient to achieve a corresponding rapid stopping of chain movement. Inertia of the chain and engine or motor components may cause there to be a delay between the securing of power application and the stopping of chain rotation. Accordingly, a chainbrake may be provided to rapidly stop the chain in addition a switch that removes power to the chain.

[0005] In some cases, it may also be desirable to have the chain stop rotating within a reasonable time period after normal release of the trigger that controls operation of the power unit. Again, inertia can keep the chain rotating after the trigger is released. Thus, some chainsaws may further include a coast brake mechanism to slow the chain when the trigger is released. Some chainsaws employ a Bowden cable to attach between the trigger and the braking system for chain braking purposes. If the braking device is mounted in the clutch cover of the chainsaw, and the Bowden cable is provided in the body of the chainsaw, it may be difficult to remove the clutch cover completely for maintenance or repair.

BRIEF SUMMARY OF SOME EXAMPLES

[0006] Some example embodiments may provide for a coast brake assembly that is split into two parts, one of which is retained in the clutch cover, while the other is retained in the body of the chainsaw. A lock out lever may also be provided to enable the two parts to be operably coupled to each other. The lock out lever may be operated to a cover detachment position to allow the clutch cover to be completely removed from the body by splitting the coast brake assembly into the two parts. Accordingly, the maintenance and/or repair of the chainsaw may be facilitated.

[0007] In one example embodiment, a hand-held power tool is provided. The hand-held power tool may include a tool body, a power unit housed within the tool body and configured to operate at least in part in response to actuation of a trigger, a working assembly powered responsive to operation of the power unit via a clutch, a clutch cover that is removable from the tool body to enable access to the clutch, and a brake assembly configured to slow the working assembly responsive to release of the trigger. The brake assembly includes a first brake member arranged in the tool body, and a second brake member arranged in the clutch cover. The second brake member is biased toward engagement with the first brake member to slow the working assembly when the trigger is not actuated. The second brake member is operably coupled to the trigger via a first force transmitting member disposed in the tool body and a second force transmitting member disposed in the clutch cover. The first and second force transmitting members are operably coupled to each other via a cover release operator such that the cover release operator includes a cover detachment position in which the first and second force transmitting members are enabled to be uncoupled for removal of the clutch cover from the tool body.

[0008] In another example embodiment, a brake assembly for a hand-held power tool is provided. The hand-held power tool may include a tool body, a power unit housed within the tool body and configured to operate at least in part in response to actuation of a trigger, a working assembly powered responsive to operation of the power unit via a clutch, and a clutch cover that is removable from the tool body to enable access to the clutch. The brake assembly includes a first brake member arranged in the tool body, and a second brake member arranged in the clutch cover and a cover release operator. The second brake member is biased toward engagement with the first brake member to slow the working assembly when the trigger is not actuated. The second brake member is operably coupled to the trigger via a first force transmitting member disposed in the tool body and a second force transmitting member disposed in the clutch cover. The first and second force transmitting members are operably coupled to each other via the cover release operator such that the cover release operator includes a cover detachment position in which the first and second force transmitting members are enabled to be uncoupled for removal of the clutch cover from the tool body.

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

[0009] Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

[0010] FIG. 1A illustrates a perspective view of a chainsaw according to an example embodiment;

[0011 ] FIG. IB illustrates a side view of the chainsaw from the opposite side of that which is shown in FIG. 1A according to an example embodiment;

[0012] FIG. 2 illustrates a partially cutaway perspective view of a clutch cover of a chainsaw that employs a cover release assembly in accordance with an example embodiment;

[0013] FIG. 3 illustrates a partially cutaway side view of the clutch cover and cover release assembly in accordance with an example embodiment;

[0014] FIG. 4 illustrates portions of the cover release assembly that remain with the chainsaw body when the clutch cover is removed in accordance with an example embodiment; [0015] FIG. 5 illustrates portions of the cover release assembly positioned when a trigger of the chainsaw is released in accordance with an example embodiment;

[0016] FIG. 6 illustrates portions of the cover release assembly positioned when the trigger of the chainsaw is activated or pressed in accordance with an example embodiment;

[0017] FIG. 7 illustrates portions of the cover release assembly that remain with the clutch cover when the clutch cover is removed while a lockout lever is not activated in accordance with an example embodiment;

[0018] FIG. 8 illustrates portions of the cover release assembly that remain with the clutch cover when the clutch cover is removed while the lockout lever is activated in accordance with an example embodiment;

[0019] FIG. 9 illustrates a perspective view of a ratchet assembly in operable

communication with the lockout lever, and capable of operable communication with the kickback guard in accordance with an example embodiment;

[0020] FIG. 10 is a side view of selected components of the kickback guard that interface with the ratchet assembly in accordance with an example embodiment;

[0021 ] FIG. 11 is an isolated perspective view of the clutch cover showing the interaction between the ratchet assembly and the lockout lever in accordance with an example embodiment;

[0022] FIG. 12 shows the kickback guard in an operating position in accordance with an example embodiment;

[0023] FIG. 13 shows the kickback guard rotated toward the front handle to engage the ratchet assembly while operating the lockout lever in accordance with an example embodiment;

[0024] FIG. 14 is a partial cutaway view of the ratchet assembly when the kickback guard is in the position shown in FIG. 13 in accordance with an example embodiment;

[0025] FIG. 15 is a closer view of the ratchet assembly of FIG. 14 in accordance with an example embodiment;

[0026] FIG. 16 is a close-up view of the ratchet assembly in a locked position in accordance with an example embodiment;

[0027] FIG. 17 shows a reverse view relative to the view of FIG. 10 showing the kickback guard interacting with the ratchet assembly in accordance with an example embodiment;

[0028] FIG. 18 illustrates the ratchet assembly in a locked position in accordance with an example embodiment; and [0029] FIG. 19 illustrates the ratchet assembly being unlocked by movement of the kickback guard to the operating position in accordance with an example embodiment.

DETAILED DESCRIPTION

[0030] 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.

[0031 ] As indicated above, some example embodiments may provide for a hand-held power tool (e.g., a chainsaw) that can be more easily maintained and/or repaired by enabling the operator to more easily (and completely) remove the clutch cover. In this regard, some example embodiments may provide a brake assembly that can be split into two parts, one of which is retained in the clutch cover, and the other of which is retained in the power tool body. The two parts mate together relatively easily and can be separated easily as well. For example, a lock out lever (with or without a ratchet function) may be used to provide relatively easy separation of the two parts. It should be appreciated that although an example embodiment will be shown and described illustrating a hand-held chainsaw, example embodiments could be practiced in connection with other similar devices such as pole saws or other cutting devices that employ a chain that rotates to affect cutting, where it is advantageous to slow the chain responsively for better performance or safety.

[0032] FIG. 1, which includes FIGS. 1A and IB, illustrates a chainsaw 100 according to the prior art. FIG. 1A illustrates a perspective view of the chainsaw 100 and FIG. IB illustrates a side view of the chainsaw 100 from the opposite side of that which is shown in FIG. 1A according to an example embodiment. It should be appreciated that the chainsaw 100 is merely one example of power equipment that includes a working assembly (i.e., the cutting components of the chainsaw 100) that may require or otherwise benefit from rapid slowing of the components thereof. Thus, example embodiments could also be practiced in connection with some other power equipment that may include working assemblies of different types.

[0033] 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. The chainsaw 100 may further include a guide bar 120 that is attached to the housing 110 along one side thereof. A chain 122 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 122 may form the working assembly of the chainsaw 100.

[0034] 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.

[0035] 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 122 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.

[0036] Some power units may employ a clutch to provide operable coupling of the power unit to a sprocket that turns the chain 122. 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 122 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 via removal of fuel cap 140. The housing 110 may also include or at least partially define an oil reservoir 150, access to which may be provided to allow the operator to pour oil into the oil reservoir 150. The oil in the oil reservoir 150 may be used to lubricate the chain 122 as the chain 122 is turned.

[0037] As can be appreciated from the description above, actuation of the trigger 136 may initiate movement of the chain 122 around the guide bar 120. Meanwhile, at least two different events may cause the movement of the chain 122 around the guide bar 120 to be interrupted or stopped. In this regard, for example, release of the trigger 136 and tripping of the hand guard 134 may cause movement of the chain 122 around the guide bar 120 to be stopped.

[0038] Tripping of the hand guard 134 occurs in response to detection of conditions indicative of a kickback. Since a kickback is an undesirable and potentially dangerous condition, movement of the chain 122 may be stopped quickly in response to tripping the hand guard 134. The chainsaw 100 may therefore be provided with a chainbrake mechanism that is configured to stop movement of the chain 122 within a first predetermined period of time after the hand guard 134 is tripped. In some cases, operation of the chainbrake mechanism may tighten a brake band around a drum (e.g., a brake drum or clutch drum).

[0039] Meanwhile, releasing of the trigger 136 is a routine event that does not necessarily present the same urgency for stopping movement of the chain 122. Thus, it may not be necessary to stop movement of the chain 122 as quickly after release of the trigger 136 as would otherwise be accomplished in response to activating the chainbrake. However, it may also be undesirable to simply allow the chain 122 to rotate responsive to inertial forces after the trigger 136 is released until the inertial forces decay away naturally. Moreover, some chainsaws may see the time it takes for the chain 122 to stop rotating after release of the trigger 136 change over time as components age. Thus, it may be desirable to facilitate coast brake of the chain 122 so that the chain 122 stops moving within a second predetermined period of time that may be different than the first predetermined period of time (e.g., longer). A coast brake function may therefore be provided by the application of friction to the rotation of a drum that is operably coupled to the chain 122 (e.g., a brake drum or clutch drum).

[0040] As mentioned above, in many conventional chainsaws, a Bowden cable is used to connect the trigger 136 to the coast brake. However, given that the braking device is typically mounted in the clutch cover of the chainsaw 100, and the Bowden cable is typically provided in the body of the chainsaw 100, it may be difficult to remove the clutch cover completely for maintenance or repair. Some example embodiments may therefore provide a brake assembly that relatively easily split into two parts so that the clutch cover can be completely removed. In an example embodiment a lockout lever may be provided to achieve this function. It should be noted, however, that although an example embodiment will be described herein in which the component that achieves the function of enabling separation of these parts is referred to as a "lockout lever," some alternative embodiments could be practiced with a similar component that performs the same function, but is not necessarily performing any lock or lockout function and may not be structured as a lever. Thus, the term "lockout lever" should be appreciated as a reference only to the name of a particular structure or operator within one example embodiment of the system. The lockout lever is therefore just one example of a cover release operator that may be employed in example embodiments. Other examples of cover release operators may include a button, sliding member, wheel, or any other operator that pivots, rotates, moves in an axial direction, radial direction or otherwise, and provides the operable coupling to release the brake band and facilitate removal of the clutch cover in the manner described herein.

[0041 ] An example embodiment will now be described in reference to FIGS. 2-8, which illustrate one example embodiment of a brake assembly that is usable in connection with a removable clutch cover. In this regard, FIG. 2 illustrates a partially cutaway perspective view of a clutch cover of a chainsaw that employs a cover release assembly in accordance with an example embodiment. FIG. 3 illustrates a partially cutaway side view of the clutch cover and cover release assembly in accordance with an example embodiment. FIG. 4 illustrates portions of the cover release assembly that remain with the chainsaw body when the clutch cover is removed in accordance with an example embodiment. FIG. 5 illustrates portions of the cover release assembly positioned when a trigger of the chainsaw is released in accordance with an example embodiment. FIG. 6 illustrates portions of the cover release assembly positioned when the trigger of the chainsaw is activated or pressed in accordance with an example embodiment. FIG. 7 illustrates portions of the cover release assembly that remain with the clutch cover when the clutch cover is removed while a lockout lever is not activated in accordance with an example embodiment. FIG. 8 illustrates portions of the cover release assembly that remain with the clutch cover when the clutch cover is removed while the lockout lever is activated in accordance with an example embodiment. [0042] As shown in FIGS. 2-8, a coast brake assembly of an example embodiment may generally include a first brake member (e.g., a brake drum (or clutch drum) represented by element 200 and disposed within a tool body 202) and a second brake member (e.g., brake band 210) that are configured to selectively engage each other. A diameter of the brake band 210 may be expanded or contracted in order to alternately release or engage the brake drum. When the brake band 210 contracts while proximate to the brake drum, the friction therebetween may rapidly slow rotation of the brake drum and therefore also the chain of the chainsaw.

[0043] The coast brake assembly also includes components configured for enabling the brake band 210 to alternately be contracted or expanded in response to specific stimuli or conditions. In one example, a first end of the brake band 210 may be secured or anchored to a portion of the clutch cover 220. For example, the clutch cover 220 may include a post 222, protrusion or other fixed member to which the first end of the brake band 210 may be connected. Meanwhile, a second end of the brake band 210 may be operably coupled to a slide assembly 230. The slide assembly 230 may be biased by a first biasing member 232 (e.g., a coasting spring) such that the slide assembly 230 is urged in a first direction 234 when the trigger is not pressed or activated. When moved in the first direction 234, as shown in FIG. 7, the brake band 210 may be contracted to have a diameter sufficient to engage the brake drum. While the trigger is pressed or activated, the slide assembly 230 may be urged in a second direction 236 such that the brake band 210 diameter increases so that the brake drum is not contacted. This will cause expansion of the brake band 210 as shown in FIG. 8.

[0044] In some cases, both the coast brake assembly and a chainbrake assembly may each operate on the same or opposite ends of the same brake band. However, in some embodiments, the coast brake assembly and the chainbrake assembly may operate with respect to different bands. Regardless of the interaction with the chainbrake assembly, some example embodiments may generally apply pressure to the brake band 210 at least in a manner similar to that which is described above in relation to operation of the trigger.

[0045] As shown in FIGS. 7 and 8, the operation of the brake band 210 via operation of the slide assembly 230 may be accomplished by tensioning provided through a force transmitting member such as a Bowden cable. However, it should be appreciated that other force transmitting members could alternatively be employed using rigid, semi-rigid, or flexible components. In FIGS. 7 and 8, operable coupling of a Bowden cable 240 to the slide assembly 230 is shown. It may be appreciated that the Bowden cable 240 could be routed from the slide assembly 230 to the trigger. Moreover, many conventional systems employ a similar structure. In such a structure, the activation of the trigger may be communicated directly to the Bowden cable 240 and the slide assembly 230 may move in the second direction 234 responsive to the activation of the trigger (again, as shown in FIG. 8). Meanwhile, when the trigger is released, the tension transmitted to the slide assembly 230 via the Bowden cable 240 may be relaxed and the slide assembly 230 may be urged back in the first direction 234 to cause the brake band 210 to contract (as shown in FIG. 7) to engage the brake drum. In a conventional system, activation of the trigger would therefore be required to disengage the brake band 210 if clutch cover 220 removal was desired. However, in a case in which the Bowden cable 240 was routed or coupled directly to the trigger, activation of the trigger would be required to release the brake band 210 from the brake drum, thereby creating an awkward and difficult situation while trying to remove the clutch cover 220.

[0046] Accordingly, example embodiments essentially split the Bowden cable (or other force transmitting member) into two pieces. One such piece stays with the chainsaw (or other power tool) body, while the other piece stays with the clutch cover 220 when the clutch cover 220 is removed. A first force transmitting member (corresponding to the first piece) may therefore extend between the trigger and a lockout lever 250. Meanwhile, a second force transmitting member (corresponding to the second piece) may therefore extend between the lockout lever 250 and the slide assembly 230. Bowden cable 240 of FIGS. 7 and 8, therefore corresponds to the second force transmitting member. Meanwhile, Bowden cable 260, which is shown in FIGS. 2- 6, corresponds to the first force transmitting member. As shown in FIGS. 7 and 8, Bowden cable 240 may be operably coupled (or fixedly attached) to a proximal end 252 of the lockout lever 250 (relative to the slide assembly 230). Meanwhile, the lockout lever 250 may be pivotally connected to the clutch cover 220 at pivot point 254, which is disposed between the proximal end of the lockout lever 250 and a driving pin 256. The driving pin 256 may extend into a coupling assembly 270 (see FIGS. 2-6) that operably couples the Bowden cable 260 to the lockout lever 250. In some examples, a distal end 258 of the lockout lever 250 may extend beyond the driving pin 256 along a longitudinal length of the lockout lever 250 such that the distal end 258 is visible when the clutch cover 220 is attached to the tool body, and is operable using, for example, a finger of the operator. [0047] In addition to being operable based on operation of the trigger, the slide assembly 230 is also operable based on operation of the lockout lever 250. FIG. 8 shows how the brake band 210 is expanded due to operation of the lockout lever 250 to manipulate the slide assembly 230 (without regard to the position of the trigger). Accordingly, example embodiments may allow the brake band 210 to be expanded by movement of the slide assembly 230 in the second direction 236 responsive either to activation of the trigger or (as shown in FIG. 8) responsive to activation of the lockout lever 250. In an example embodiment, the lockout lever 250 may be considered to be activated when the lockout lever 250 is moved to a "cover detachment position" in which the lockout lever 250 is pivoted in a direction toward the trigger (as shown by arrow 272 in FIG. 8). Thus, when the lockout lever 250 is rotated in the direction of arrow 272, the brake band 210 may be expanded to ensure disengagement between the brake band 210 and the brake drum, and the clutch cover 220 may be removed from the tool body without requiring the trigger to be activated or pressed. The clutch cover 220 can therefore be completely and easily removed from the tool body.

[0048] When the clutch cover 220 is mated back together with the tool body, as shown in FIGS. 2 and 3, the driving member 256 may couple the lockout lever 250 to the coupling assembly 270, as indicated above. The coupling assembly 270 may include a cable lug 280 disposed within an elongated shaft 282 and biased by a biasing member 284 that tends to urge the cable lug 280 in a direction shown by arrow 286 in FIG. 3. The cable lug 280 may be operably coupled to the Bowden cable 260. The Bowden cable 260 may extend from the cable lug 280 to the trigger. Of note, in FIGS. 3-6, the Bowden cable 260 is shown passing behind the front handle 290. However, in this example embodiment, the Bowden cable 260 is nevertheless a single unitary cable.

[0049] When the trigger is released, the Bowden cable 260 may be in a rest position biased toward the direction shown by arrow 286 by the biasing member 284. FIG. 5 illustrates the rest position. However, when the trigger is actuated, the Bowden cable 260 may transmit a force to pull the cable lug 280 in a direction opposite the direction shown by arrow 286 to compress the biasing member 284 and position the cable lug 280 in an actuated position. FIG. 6 illustrates the cable lug 280 in the actuated position. It should be appreciated that the driving member 256 extends into an engagement slot 292 disposed in the cable lug 280 when the clutch cover 220 is mated to the tool body 202. FIG. 2 provides a clear view of the driving member 256 extending into the engagement slot 292 in this manner. Moreover, when the cable lug 280 is moved to the actuated position (as shown in FIG. 6), the movement of the cable lug 280 will cause

corresponding rotation of the lockout lever 250 to the position shown in FIG. 8 to expand the brake band 210 as described above.

[0050] Accordingly, when the trigger is actuated, the Bowden cable 260 overcome the biasing force of the biasing member 284 to move the cable lug 280 in a direction opposite the direction shown by arrow 286. The engagement slot 292 is moved accordingly and engages the driving member 256 to urge the driving member 256 such that the lockout lever 250 rotates to the activated or cover detachment position as shown in FIG. 8. The lockout lever 250 rotates about the pivot point 254 and displaces the proximal end 252 such that the Bowden cable 240 exerts a force to overcome the biasing force exerted by the first biasing member 232 and move the slide assembly 230 in the second direction 236 to expand the diameter of the brake band 210 as shown in FIG. 8.

[0051 ] If the trigger is released, the Bowden cable 260 no longer overcomes the biasing force of the biasing member 284 and the cable lug 280 moves back in the direction shown by arrow 286. The engagement slot 292 is moved accordingly and the driving member 256 is allowed to pivot back out of the activated or cover detachment position (i.e., opposite the direction shown by arrow 272) to return the lockout lever 250 to the position shown in FIG. 7. The Bowden cable 240 no longer exerts a force to overcome the biasing force exerted by the first biasing member 232 and the slide assembly 230 is therefore moved in the first direction 234 responsive to the biasing force of the first biasing member 232 to cause the diameter of the brake band 210 to contract as shown in FIG. 7.

[0052] Of note, however, if the trigger can remain in the released or not-actuated position and the diameter of the brake band 210 can still be expanded in the manner shown in FIG. 8 when the lockout lever 250 is directly operated by the operator moving the lockout lever 250 in the direction of arrow 272. Movement of the lockout lever 250 directly by the operator may not only expand the diameter of the brake band 210, but may do so without impacting the position of the cable lug 280 by virtue of the arrangement of the engagement slot 292 relative to the driving pin 256. In this regard, the engagement slot 292 is configured so that activation of the trigger causes movement of the Bowden cable 260 to move the cable lug 280 and thereby also move the driving pin to rotate the lockout lever 250. However, movement of the lockout lever 250 directly by the operator may not move the cable lug 280, the Bowden cable 260 or the trigger. In particular, because the engagement slot 292 is elongated, movement of the lockout lever 250 to the activated or cover detachment position causes the driving pin 256 to ride in the engagement slot 292 in the direction shown by arrow 294 (see FIG. 5) without causing movement of the cable lug 280. Thus, for example, the trigger may remain in the released position as shown in FIG. 5, while the driving member 256 slides in the direction shown by arrow 294 as the lockout lever transitions and causes the brake band 210 expansion shown in FIG. 8.

[0053] Accordingly, the lockout lever 250 may provide the function of enabling the brake band 210 to be disengaged from the brake drum without operation of the trigger. Additionally, the first force transmitting member (e.g., Bowden cable 260) that connects the trigger to the coupling assembly 270 can be completely detached from the second force transmitting member (e.g., Bowden cable 240) that operably couples the brake band 210 to the lockout lever 250. Therefore, the clutch cover 220 can be completely and relatively easily removed from the tool body 202 to facilitate maintenance or repair. However, in the example of FIGS. 2-8, the operator is still generally required to hold the lockout lever 250 in the cover detachment position (or activated position) in order to facilitate release of the clutch cover 220. Meanwhile, some example embodiments may employ a ratchet assembly to enable the lockout lever 250 to be held in the cover detachment position until the ratchet assembly is further operated to release the ratchet function.

[0054] FIGS. 9-19 illustrate an example embodiment that further incorporates a ratchet assembly 300 capable of operating as described above. Moreover, FIGS. 9-19 illustrate such example in a manner that builds off of the description already provided in reference to FIGS. 2-8. Thus, the functions, structures and operations of components described in connection with FIGS. 2-8 should be understood to be the same in relation to the operations described in reference to the descriptions of FIGS. 9-19 except where specifically noted. FIGS. 9-19 therefore add the ratchet assembly 300 and corresponding components thereof, and that work therewith, to facilitate operation of this alternative embodiment. The ratchet assembly 300 also incorporates a kickback guard 310 (similar to hand guard 134 of FIG. 1) to facilitate operation of the ratchet assembly 300 so that the operator need not actuate the lockout lever 250 with fingers.

[0055] FIG. 9 illustrates a perspective view of a ratchet assembly in operable communication with the lockout lever, and capable of operable communication with the kickback guard in accordance with an example embodiment. FIG. 10 is a side view of selected components of the kickback guard that interface with the ratchet assembly in accordance with an example embodiment. FIG. 11 is an isolated perspective view of the clutch cover showing the interaction between the ratchet assembly and the lockout lever in accordance with an example embodiment. FIG. 12 shows the kickback guard in an operating position in accordance with an example embodiment. FIG. 13 shows the kickback guard rotated toward the front handle to engage the ratchet assembly while operating the lockout lever in accordance with an example embodiment. FIG. 14 is a partial cutaway view of the ratchet assembly when the kickback guard is in the position shown in FIG. 13 in accordance with an example embodiment. FIG. 15 is a closer view of the ratchet assembly of FIG. 14 in accordance with an example embodiment. FIG. 16 is a close-up view of the ratchet assembly in a locked position in accordance with an example embodiment. FIG. 17 shows a reverse view relative to the view of FIG. 10 showing the kickback guard interacting with the ratchet assembly in accordance with an example embodiment. FIG. 18 illustrates the ratchet assembly in a locked position in accordance with an example embodiment. FIG. 19 illustrates the ratchet assembly being unlocked by movement of the kickback guard to the operating position in accordance with an example embodiment.

[0056] Referring now to FIGS. 9-19, it should be noted that the kickback guard 310 has two general positions that are applicable to interaction with the ratchet assembly. In this regard, the kickback guard 310 may be in an operating position where the kickback guard 310 is rotated to its "normal" operating position in which the chainbrake is not applied. The operating position is shown at least in FIGS. 9, 12, 17 and 19. The second general position may be referred to as the cover detachment position. When the kickback guard 310 is in the cover detachment position, the kickback guard 310 may cause positioning of the lockout lever 250 into the cover detachment position as described above. In the cover detachment position, the kickback guard 310 may be drawn toward the front handle 290. The kickback guard 310 is shown in the cover detachment position at least in FIGS. 13, 14 and 18. Meanwhile, although not shown itself, the kickback guard 310 should be understood to be in the cover detachment position in FIGS. 15 and 16 as well. In some cases, the kickback guard 310 may not be considered to be in the cover detachment position (and therefore may not operate the lockout lever 250 to move the lockout lever 250 to the cover detachment position, until the kickback guard 310 is moved proximate to the front handle 290 with relatively little space therebetween. Thus, for example, accidental movement of the kickback guard 310 toward the front handle 290 while the operator is grasping the front handle 290 may cause the operator's fingers to prevent movement of the kickback guard 310 far enough to actuate the lockout lever 250.

[0057] The kickback guard 310 may be configured to pivot and operate in the general manner described herein and/or as known conventionally except that the kickback guard 310 may be augmented to include features for interaction with the ratchet assembly 300. The features may include an actuation paddle 312 and a lock disengagement member 314. The actuation paddle 312 and the lock disengagement member 314 may be disposed on the same side of the kickback guard 310, and may be in substantial registration with corresponding components of the ratchet assembly 300. When the kickback guard 310 is rotated to the cover detachment position, the actuation paddle 312 may engage the ratchet assembly 300 to cause the ratchet assembly 300 to actuate the lockout lever 250 (e.g., to the cover detachment position thereof) and hold the lockout lever 250 in such position as described in greater detail below. Meanwhile, when the kickback guard 310 is rotated to the operating position, the lock disengagement member 314 may engage the ratchet assembly 300 to cause the ratchet assembly 300 to stop holding the lockout lever 250 in the actuated position and allow the lockout lever 250 to return to its rest position as described in greater detail below. Of note, in some embodiments, the actuation paddle 312 may only interact with the ratchet assembly 300 when the kickback guard 310 is drawn fully (or nearly fully) back toward the front handle 290. However, the lock disengagement member 314 may engage the ratchet assembly 300 over substantially an entire range of motion of the kickback guard 310 between the operating position and the cover detachment position.

[0058] The ratchet assembly 300 may include a housing 320 that may be affixed to the clutch cover 220 at a portion of the clutch cover 220 that is proximate to the positioning of the lockout lever 250. Thus, in some embodiments, when the clutch cover 220 is removed, the ratchet assembly 300 may be removed with the clutch cover 220 while still holding the lockout lever 250 in the cover detachment position so that the brake band 210 is expanded. The housing 320 may have a shaft passing therethrough, and an actuating rod 330 may be movable in an axial direction within the shaft. The actuating rod 330 may have a first end 332 disposed to face toward the lockout lever 250 and a second end 334 disposed to face away from the lockout lever 250. In some embodiments, the second end 334 may have a slot 336 disposed proximate thereto and extending in a radial direction around a portion of the actuating rod 330. The slot 336 may be formed as a groove within the second end 334 of the actuating rod 330 or as a groove within a plunger or other end piece of the actuating rod 330 that is positioned at the second end 334. Alternatively, the slot 336 may be formed by a radially outwardly extending protrusion that extends off of the second end 334 of the actuating rod 330 or off of the plunger or other end piece of the actuating rod 330 that is positioned at the second end 334.

[0059] In an example embodiment, the actuating rod 330 may be biased away from the lockout lever 250 by a biasing member 338. The biasing member 338 may be a spring or other such member capable of placing a biasing force on the actuating rod 330. In an example embodiment, the biasing member 338 may be compressible between a portion of the housing 320 that is closest to the lockout lever 250 and a lug, plunger or other larger diameter portion of the actuating rod 330 proximate to the second end 334 thereof to build up the biasing force.

[0060] The ratchet assembly 300 may also include a ratchet brace 340 that may be disposed within or proximate to the housing 320 (e.g., proximate to or within the shaft) to be biased toward engagement with the slot 336. As such, if the actuating rod 330 is moved axially within the shaft toward the lockout lever 250 responsive to the actuation paddle 312 urging the actuating rod 330 when the kickback guard 312 is rotated to the cover detachment position, and the actuating rod 330 is moved far enough to align the slot 336 with the ratchet brace 340, the ratchet brace 340 will be biased to enter into the slot 336 to lock the actuating rod 330 into contact with the lockout lever 250 in its cover detachment position (as described above in reference to FIGS. 2-8).

[0061 ] The first end 332 may engage the lockout lever 250 when the actuation paddle 312 is rotated into contact with the actuating rod 330 as shown in FIGS. 13, 14 and 15. Once the ratchet brace 340 is seated in the slot 336 to lock the actuating rod 330 in position, the actuation paddle 312 could be removed from contact with the actuating rod 330 (e.g., when the clutch cover 220 is removed) and the actuating rod 330 will remain locked in place as shown in FIG. 16.

[0062] Unseating of the ratchet brace 340 from the slot 336 may "unlock" the ratchet assembly 300 and allow the actuating rod 330 to move back to its rest position responsive to the biasing force exerted by the biasing member 338. In an example embodiment, the lock disengagement member 314 may release or unseat the ratchet brace 340 from the slot 336 responsive to movement of the kickback guard 310 from the cover detachment position to the operating position.

[0063] As shown in FIGS. 18 and 19, the lock disengagement member 314 may be embodied as a curved protrusion or finger that extends substantially perpendicularly relative to the direction of extension of the actuation paddle 312. In some embodiments, the curvature of the lock disengagement member 314 may be formed such that the arc formed by the curvature is substantially equidistant from the axis of rotation of the kickback guard 310. However, the lock disengagement member 314 may further include a ratchet brace disengagement protrusion 350 at an end portion thereof, and the diameter of the lock disengagement member 314 at the ratchet brace disengagement protrusion 350. Moreover, the ratchet brace disengagement protrusion 350 may have a sloped portion 352, which gradually increases the diameter of the lock

disengagement member 314 over the ratchet brace disengagement protrusion 350 while proceeding toward the end of the lock disengagement member 314.

[0064] When the kickback guard 310 is rotated to the cover detachment position as shown in FIG. 18, the actuation paddle 312 may engage the actuating rod 330 and urge the actuating rod 330 toward the lockout lever 250. When the actuating rod 330 is pushed far enough forward to place the ratchet brace 340 in registration with the slot 336, the ratchet brace 336 may engage the slot 336 to lock the ratchet assembly 300 as described above. While the ratchet assembly 300 is being locked in this manner, as described above in reference to FIGS. 13 and 15, a center portion of the lock disengagement member 314 may ride over (with or without contact) the ratchet brace 340 without causing the ratchet brace 340 to unseat from the slot 336, as shown in FIG. 18. This is because the ratchet brace disengagement protrusion 350 is not in contact with the ratchet brace 340 in this configuration (again as shown in FIG. 18). However, when the kickback guard 310 is rotated from the cover detachment position (shown in FIG. 18) to the operating position as shown in FIG. 19, the ratchet brace 340 engages the sloped portion 352 and is gradually unseated from the slot 336 as the ratchet brace 340 rides up the sloped portion 352. At some point along the sloped portion 352, the ratchet brace 340 may be disengaged or unseated from the slot 336 and the actuating rod 330 may be moved back to its rest position under influence from the biasing member 338 as shown in FIG. 19.

[0065] Accordingly, movement of the kickback guard 310 to the cover detachment position may cause the actuating paddle 312 to engage the actuating rod 330 and move it until the ratchet assembly 300 can be locked, as shown in FIG. 18. At that point, the clutch cover 220 can be removed and the ratchet assembly 300 will continue to hold the brake drum 210 in its expanded condition. This may be the case even though the actuating paddle 312 no longer contacts the actuating rod 330 due to the locking of the ratchet assembly 300. When the clutch cover 220 is reassembled onto the tool body 202, the kickback guard 310 may be moved back to the operating position. Movement of the kickback guard 310 back to the operating position may cause the ratchet assembly 300 to be unlocked in the manner described above. Then, the brake drum 210 may expand and contract based on trigger position, as described above, until the kickback guard (or the lockout lever 250) is moved back to the cover detachment position.

[0066] Example embodiments may therefore provide a relatively easy way to disassemble the clutch cover to facilitate maintenance or repair of the power tool (e.g., the chainsaw).

[0067] A hand-held power tool of an example embodiment may include a tool body, a power unit housed within the tool body and configured to operate at least in part in response to actuation of a trigger, a working assembly powered responsive to operation of the power unit via a clutch, a clutch cover that is removable from the tool body to enable access to the clutch, and a brake assembly configured to slow the working assembly responsive to release of the trigger. The brake assembly includes a first brake member arranged in the tool body, and a second brake member arranged in the clutch cover. The second brake member is biased toward engagement with the first brake member to slow the working assembly when the trigger is not actuated. The second brake member is operably coupled to the trigger via a first force transmitting member disposed in the tool body and a second force transmitting member disposed in the clutch cover. The first and second force transmitting members are operably coupled to each other via a cover release operator such that the cover release operator includes a cover detachment position in which the first and second force transmitting members are enabled to be uncoupled (i.e., physically and completely separable from each other) for removal of the clutch cover from the tool body.

[0068] The power tool (or brake assembly) of some embodiments may include additional features that may be optionally added either alone or in combination with each other. For example, in some embodiments, (1) the cover release operator may be pivotally connected to the clutch cover. In some cases, (2) the cover release operator releasably engages a coupling assembly disposed at the tool body. In an example embodiment, (3) the cover release operator includes a driving pin that projects into a cable lug of the coupling assembly, the cable lug being operably coupled to the first force transmitting member. In some embodiments, (4) the cover release operator translates a force exerted on the first force transmitting member via actuation of the trigger to the second brake member via the second force transmitting member in response to movement of the cable lug causing corresponding movement of the driving pin to rotate the cover release operator. In some cases, (5) the cable lug comprises an engagement slot in which the driving pin is enabled to move responsive to manual rotation of the cover release operator such that rotation of the cover release operator does not translate any force to the first force transmitting member.

[0069] In some embodiments, any or all of the items (1) to (5) above may be provided individually or in combination with each other and rotation of the cover release operator to the cover detachment position may cause exertion of force on the first force transmitting member to disengage the second brake member from the first brake member while the trigger is released. Additionally or alternatively, any or all of the items (1) to (5) above may be provided individually or in combination with each other and the power tool may further include a ratchet assembly that is configured to lock the cover release operator in the cover detachment position. Additionally or alternatively, any or all of the items (1) to (5) above may be provided individually or in combination with each other and the ratchet assembly may be disposed proximate to the cover release operator. The ratchet assembly may include an actuating rod biased away from contact with the cover release operator. The ratchet assembly may be configured to lock the cover release operator in the cover detachment position responsive to a ratchet brace aligning with a slot disposed at the actuating rod. Additionally or alternatively, any or all of the items (1) to (5) above may be provided individually or in combination with each other and the actuating rod may include a first end facing the cover release operator and a second end extending away from the cover release operator. The hand-held power tool may further include a kickback guard configured to interact with the second end of the actuating rod to selectively cause the first end of the actuating rod to lock the cover release operator in the cover detachment position. Additionally or alternatively, any or all of the items (1) to (5) above may be provided individually or in combination with each other and the kickback guard may include an actuation paddle disposed to interact with the actuating rod by contacting the second end of the actuating rod to overcome biasing of the actuating rod as the kickback guard is rotated to a detachment position. Additionally or alternatively, any or all of the items (1) to (5) above may be provided individually or in combination with each other and the kickback guard may include a lock disengagement member configured to disengage the ratchet brace from the slot responsive to the kickback guard being rotated from the detachment position to an operating position. In any of the situations described above, the power tool may be a chainsaw or another cutting device.

[0070] 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.