FIELD [0001] This disclosure relates to the field of cutting machines, and more particularly, to linkage systems for remote chain sharpening.

BACKGROUND [0002] Devices with cutting tools require replacement or sharpening of the cutting tool in order to maintain their efficiency and/or ability to perform their intended purpose. For example, a cutting device, such as a chain saw, has a cutting tool such as a chain for cutting wood. Over time, the chain can become dull. Maintaining the sharpness of the chain is particularly important for maintaining cutting efficiency which can also improve the safety of using the chain saw. [0003] Industrial-sized sharpeners are available to sharpen chains for chain saws, but their use is cumbersome and time-consuming. Typically, the chain must be removed from the chain saw and left with an operator of the industrial-sized chain sharpener until the chain has been sharpened and is ready for pickup. Such sharpeners are inconvenient for a variety of reasons, the chain needs to removed and re-installed, the chain has to be brought to and from a store, the chain saw is inoperable until the chain is re -installed, and the owner has to pay someone to sharpen the chain.

[0004] Other sharpeners are available that allow the saw chain to remain on the saw during sharpening. Such devices typically include a fixture that clamps on to the chain saw to guide a hand file for individually sharpening each saw tooth of the chain. While such devices are portable, their use is time-consuming because the operator must hand file each tooth separately.

[0005] As a result self-sharpening chain saws have become available where a sharpener is built into the housing or is attachable to the housing of the chain saw such that the chain is either automatically sharpened as the saw is used or sharpened whenever the operator actuates a sharpening lever or knob. Such devices often have numerous and complex components to fasten the sharpener to the chain saw housing. The components are used to keep the sharpener out of the way of the chain when the saw is used for cutting. There can also be additional components within the sharpening housing to ensure proper movement of a sharpening stone into contact with the chain.

[0006] Additionally, these numerous and complex components can interfere with critical components of the chain saw such as vibration isolation components or strength reinforcement components. Even more, placement of these critical components often result in placing the sharpener in locations on the chain saw that are uncomfortable or awkward for a user to operate. In some chain saws, the saw must be placed on the ground or propped against something to actuate the sharpening mechanism. As chain saws and the like have included complex systems designed to improve the user experience, the space available for additional components is diminished. As described herein, the present disclosure presents a solution to a problem where the user interface for engaging the sharpening mechanism cannot be placed in direct contact with the sharpening mechanism because of the various components of the chain saw, which have been optimized for their location, such that direct engagement is neither economical nor ergonomic.

[0007] Therefore, there is a need for a linkage system for remotely actuated sharpening that can reduce the complexity of a self-sharpening chain saw, improve the efficiency of sharpening the chain and/or improve the safety of using the chain saw.

SUMMARY

[0008] The present disclosure is directed to a linkage system for remote chain sharpening. The linkage system for remote chain sharpening can include an actuation mechanism for interacting with a sharpening mechanism on a chain saw that is simple, efficient, and improves the safety of using the chain saw.

[0009] One embodiment takes the form of an actuation mechanism for a sharpening mechanism having a linkage coupled to an engagement mechanism at a first end and coupled to a sharpening mechanism at a second end. The linkage directly transfers force applied at the first end of the linkage to the second end of the linkage. The linkage can include a linkage arm configured to be pivotally coupled to a chain saw housing. The actuation mechanism can also include an engagement mechanism having a distal end spaced a distance from a proximal end. The engagement mechanism can have a linkage contact portion. During operation, the linkage contact portion of the engagement mechanism contacts the linkage, thereby actuating the sharpening mechanism and aligning the sharpening stone of the sharpening mechanism with the cutting chain of the chain saw for sharpening.

[0010] Additionally the linkage system allows a user to actuate the sharpening mechanism from a remote location, thereby facilitating safe use and suitable placement of the actuation mechanism used to sharpen the cutting chain of the chain saw.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The foregoing features of the disclosure will be more readily understood by reference to the following detailed description, taken with reference to the accompanying drawings, in which:

[0012] FIG. 1 is a perspective view of a linkage system for chain sharpening without a sharpening mechanism in accordance with an exemplary embodiment;

[0013] FIG. 2 is a perspective view of the linkage system for chain sharpening with a sharpening mechanism in accordance with an exemplary embodiment;

[0014] FIG. 3 is a front view of the linkage system for chain sharpening configured in a chain saw having a sharpening mechanism and a cutting chain in accordance with an exemplary embodiment;

[0015] FIG. 4 is a perspective view of the linkage arm of the linkage system for chain sharpening in accordance with an exemplary embodiment and

[0016] FIG. 5 is a partial view of a chain saw having bosses on the chain saw housing and configured with the linkage system for chain sharpening in accordance with an exemplary embodiment.

DETAILED DESCRIPTION

[0017] A linkage system for remote chain sharpening configured according to the present teachings will hereinafter be described more fully with reference to the accompanying drawings in which exemplary embodiments of the system are illustrated. This system can, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those persons skilled in the art. In the figures and description, like reference numbers refer to like elements throughout. [0018] Referring to FIGS. 1 and 2, perspective views of a linkage system 400 for chain sharpening without a sharpening mechanism and with a sharpening mechanism 100, respectively, in accordance with exemplary embodiments are illustrated. The linkage system 400 can include a linkage 405 coupled to an engagement mechanism 530 at a first end of the linkage 405 and coupled to a sharpening mechanism 100 at a second end of the linkage 405. The engagement mechanism 530 can have a proximal end extending at least partially beyond the chain saw housing 520. The engagement mechanism 530 can also have a distal end spaced a distance from the proximal end. The sharpening mechanism 100 is located proximal to a cutting chain of the chain saw and has a stone for sharpening the cutting chain. The linkage 405, engagement mechanism 530, and sharpening mechanism 100 are configured and oriented such that the linkage 405 directly transfers force from the engagement mechanism 530 applied at the first end of the linkage 405 to the sharpening mechanism 100 positioned coupled to the second end of the linkage 405.

[0019] The linkage 405 can have a linkage arm 410 configured to be pivotally coupled to a chain saw housing 520 at the first end 412 of the linkage arm 410. The linkage arm 410 can be coupled to the chain saw housing 520 at the first end 412 of the linkage arm by a screw, bolt, pin, or other coupling attachment. The second end 414 of the linkage arm 410 actuates the sharpening mechanism 100 and can be substantially flat. In other embodiments, the second end

414 can be rounded, pointed, or have another shape. A linkage contact portion 532 can be located at the distal end of the engagement mechanism 530 to contact the linkage arm 410 between the first end 412 and the second end 414. The linkage arm 410 can also have a flattened portion 420 between the first end 412 and second end 414 for contact with the linkage contact portion 532 of the engagement mechanism 530. One of ordinary skill in the art will understand that the linkage arm 410 can have a rounded portion or other portion between the first end 412 and the second end 414. When the engagement mechanism 530 is actuated, the linkage contact portion 532 engages the linkage arm 410, which thereby actuates the sharpening mechanism 100 (shown in FIG. 3). In an alternative embodiment, the linkage contact portion 532 and the linkage arm 410 can be connected in such a way that they are always in contact with each other. One of ordinary skill in the art will appreciate that the linkage arm 410 can be coupled elsewhere on the chain saw 500 other than the chain saw housing 520. For example, the linkage arm 410 can be coupled to the clutch cover, a handle, or other components of the chain saw 500. Additionally, as used herein chain saw housing 520 refers to the portion of the chain saw that is portion of the saw that is the outer shell of the chain saw and within the outer shell. One of ordinary skill in the art will also appreciate that the linkage arm 410 can be coupled to the chain saw at a point different from the first end 412 of the linkage arm, such as at a point between the first end 412 and the second end 414 of the linkage arm 410.

[0020] The linkage arm 410 is shaped such that the linkage arm 410 can directly transfer force applied by the engagement mechanism 530 to the chain sharpening mechanism 100 from a direction that is not in a constant plane. For example, as illustrated in FIGS. 2 and 3, the engagement mechanism 530 actuates a sharpening mechanism 100 in an engagement direction 136 which is different from the traveling direction 132 of the sharpening stone of the sharpening mechanism 100. This allows for a more compact and user friendly chain saw 500.

[0021] FIG. 2 illustrates an exemplary embodiment of the linkage arm. In the illustrated embodiment, the linkage arm 410 can be curvilinear in shape. Such shape provides a compact linkage system 400 that will not interfere with other parts of the chain saw. The curvilinear shape also allows the engagement mechanism 530 to be placed in a position more suitable for user access and safety. The curvilinear shape of the linkage arm 410 can also be positioned around critical features of the saw such as the vibration isolation components and around other areas critical for strength and safety. [0022] The linkage 405 can be configured to transfer force from the engagement mechanism 530 between differing angles of the sharpening mechanism 100. For example, the linkage 405 can be a single integrally formed linkage arm 410, as illustrated in FIG. 4. Alternatively, the linkage 405 can have multiple segments to create the angles that transfer force from the engagement mechanism 530 to the sharpening mechanism 100. In some embodiments, the linkage 405 can be rigid, such as a rigid linkage arm. For example, a rigid linkage 405 can be made of rigid material, such as hard plastic or metal. In other embodiments, the linkage 405 can be flexible. For example, a flexible linkage 405 can be made of an elastic material, such as a rubber tube, cable, or cord.

[0023] The second end 414 of the linkage arm 410 can be flat. This ensures sufficient contact with the sharpening mechanism 100 to actuate the sharpening stone. It also ensures that the force applied by the operator on the engagement mechanism 530 is sufficiently transferred to the sharpening mechanism 100 to expose the sharpening stone during sharpening of the cutting chain 550, as shown in FIG. 3. In other embodiments, the second end 414 of the linkage arm 410 can be rounded, pointed, or non-flat.

[0024] Alternatively, as illustrated in FIG. 5, the actuation mechanism 400 can have at least one boss 430 on the chain saw housing 520 for guiding the linkage 405 between the engagement mechanism 530 and the sharpening mechanism 100. For example, if the linkage 405 is flexible, the plurality of bosses 430 depicted in FIG. 5 guide the linkage 405 between the engagement mechanism 530 and the sharpening mechanism 100. In this embodiment, the force applied to the linkage 405 from the engagement mechanism 530 can still be directly transferred to the sharpening mechanism 100. The linkage 405 and the bosses 430 allow the engagement mechanism 530 to be placed at a more user- friendly position while maintaining a compact chain saw. The at least one boss 530 can be placed on the chain saw housing 520 so that the linkage 405 can be positioned around essential components of the chain saw to directly transfer force applied by the engagement mechanism 530 to the sharpening mechanism 100. One of ordinary skill in the art will appreciate that the at least one boss 530 can be a protrusion from the chain saw housing, a rib, a tab, a lip, or other similar protrusion. In other embodiments, the at least one boss 530 can be located elsewhere on the chain saw 500. For example, the at least one boss 530 can be located on the clutch cover, the handle, or other components of the chain saw 500.

[0025] Operation of the actuation mechanism 400 will be described in relation to a sharpening mechanism 100 that has a body having a first connector for mating engagement with a second connector on the chain saw and a fastener for releasably attaching the body to the chain saw. The first and second connectors can align the sharpening mechanism 100 with a cutting chain. Returning to FIGS. 2 and 3, the exemplary sharpening mechanism 100 depicted can have a cavity formed within the body of the sharpening mechanism 100. A partial wall is located within the cavity, separating the cavity into a first portion and second portion. A sharpening stone is at least partially located within the first portion of the cavity on one side of the partial wall. A rod 170 is coupled to the stone, and the distal end of the rod 170 extends beyond an edge of the body, as shown in FIGS. 2 and 3. The rod 170 is coupled to the sharpening stone such that it moves the stone from a retracted position to an exposed position. A bias member 180 is also provided to bias the stone in a retracted position, where the majority of the stone is located within the first portion of the cavity.

[0026] During chain saw sharpening, the operator actuates the engagement mechanism 530 by exerting a force within the engagement mechanism 530 in an engagement direction 136. FIGS. 1-3 illustrate an exemplary engagement mechanism 530 that is an indexing mechanism. The engagement mechanism 530 is actuated by exerting a force or pressing down on the knob at the top of the engagement mechanism 530. This force is transferred onto the linkage arm 410 of the linkage 405 via the linkage contact portion 532 of the engagement mechanism 530. The linkage contact portion 532 of the engagement mechanism 530 is pressed onto the flattened portion 420 of the linkage 405. The flattened portion 420 maximizes contact between the linkage arm 410 and the engagement mechanism 530. The force from the engagement mechanism 530 is transferred on to the flattened portion 420 and pivots the linkage arm 410 about the first end 412 that is coupled to the engine housing 520. As the linkage arm 410 pivots, the second end 414 comes into contact with the rod 170 of the sharpening mechanism 100 to actuate the sharpening mechanism 100. The force that was exerted on the engagement mechanism 530 becomes the force that drives the rod 170 of the sharpening mechanism 100. The force moves the rod 170 through the housing of the sharpening mechanism 100, and as a result of being coupled with the sharpening stone, the rod 170 moves the sharpening stone from a first position (e.g., a retracted position) to a second position (e.g., an exposed position). In the exposed position, the sharpening stone can contact and sharpen the cutting chain 550. Specifically, the sharpening stone can sharpen each tooth of the cutting chain 550 in a safe and efficient manner.

[0027] As seen in FIGS. 2 and 3, because the second end 414 of the linkage arm 410 contacts the sharpening mechanism 100, the engagement mechanism that is controlled by the chain saw operator can be placed at a safe and convenient location on the chain saw 500. This allows for a more compact chain saw having an integrated chain saw sharpening mechanism. Additionally, chain sharpening is safer because activation of the sharpening mechanism 100 is done while holding the chain saw unit rather than by manually sharpening the teeth of the cutting chain 550. Chain sharpening is also more efficient since the saw chain can be sharpened without setting the chain saw down. This also reduces the chance of the operator touching the newly sharpened chain to the ground or to dirt, which could cause undue wear on the chain.

[0028] Exemplary embodiments have been described hereinabove regarding chain sharpening mechanisms and their operation within a chain saw. It should be appreciated, however, that a focus of the present disclosure is linkage systems for remote chain sharpening.

[0029] INDUSTRIAL APPLICABILITY: The present disclosure finds applicability in the power tool and industrial tool industries.