TECHNICAL FIELD

The present invention relates in general to sharpening a chain of a chain saw, and in particular, to a filing fixture guide for aiding manual filing of the chain of the chain saw.

BACKGROUND

Cutting links of a chain in a chain saw dull at an unpredictable rate depending on various parameters. For example, the type of wood, the moisture content of the wood, and the force exerted by the operator of the chain saw, etc. may be some variables determining the rate at which the cutting links dull. A chain saw with dull cutting links not only cuts slowly but can be a safety hazard to the operator due to the increased effort and force needed to drive the saw through the wood.

One solution for the operator is to change chains, a process which requires not only a supply of extra chains, but proper tools and a suitable work surface. Typically, under field working conditions, this option is not exercised unless a chain breaks. More likely, the operator elects to perform a quick sharpening of the cutting teeth using an easily carried file.

There are various known methods for manually and automatically filing the chain saw. For manual filing, a person holds the file with hand and files the cutting links of the chain of the chain saw. However, loosely holding the file may not be a desirable option as this may cause accidents. Moreover, automatic filing machines or devices are very expensive and may not be desirable too.

Therefore, in light of the foregoing, there is a need for an efficient, safe and reliable filing fixture that aides in manual filing of the chain of the chain saw. SUMMARY

In view of the above, it is an objective of the present invention to solve or at least reduce the problems discussed above. In particular, the objective is to provide an improved fixture for filing a chain in a chain saw.

The objective is at least partially achieved according to a novel fixture configured to file a chain of a chain saw, as described in claim 1 . The fixture includes a pair of flanges, each of the flanges having a first end and a second end. A first connecting portion connects the flanges at their first ends, and a second connecting portion connects the flanges at their second ends. The first connecting fixture includes at least a pair of counter holds, wherein the pair of counter holds are configured to provide area contact with a guide bar of the chain saw. Thus, the counter holds enable a tight and strong grip of the fixture onto the guide bar of the chain saw. Further, the fixture includes a cam portion pivotally connected to the second connecting portion. The cam portion and at least one of the counter holds simultaneously secure the fixture to the guide bar. This enables safe and reliable filing of various components of the chain.

According to claim 2, the first connecting portion is of a substantially triangular shape, the counter holds being provided on two edges. Such a configuration ensures that one counter hold contacts the guide bar when the fixture is mounted obliquely relative to the guide bar. Further, according to claim 3, the counter holds are integrally formed with the first connecting portion. Alternatively, according to claim 4, the counter holds are attached to the first connecting portion using at least one of riveting, welding, and bolting.

According to claim 5, the second connecting portion is of a substantially triangular shape, one edge including an indentation. The indentation enables the cam portion to extend beyond the edge of the second connecting portion and engage with the guide bar.

According to claim 6, the cam portion is extended to form a sheet metal guide. According to claim 7, the sheet metal guide includes multiple channels to engage multiple portions of the chain. Further, according to claim 8, the sheet metal guide includes at least one aperture which is shaped to enable filing of at least one depth gauge of the chain. According to claim 9, each of the flanges includes at least one pair of recessed portions configured to engage a plurality of portions of the chain. At least two recessed portions of the flanges, at least one counter hold, and the cam portion simultaneously secure the fixture to the chain and guide bar. Thus, the fixture is secured at four positions.

According to claim 10, the fixture further includes a first rotatable cylindrical roller configured to be connected to the first end of each of the flanges, and a second rotatable cylindrical roller oriented substantially parallel to the first rotatable cylindrical roller, and connected to the second end of each of the flanges. The first and second rotatable cylindrical rollers are configured to support a file during filing.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will in the following be described in more detail with reference to the enclosed drawings, wherein:

FIG. 1 illustrates a perspective view of a fixture for filing a chain of a chain saw, according to an embodiment of the present invention;

FIG. 2 illustrates a perspective view of the fixture mounted on a chain and a guide bar, according to an embodiment of the present invention;

FIG. 3A illustrates a front perspective view of the fixture mounted on the chain and the guide bar in an alternative configuration, according to an embodiment of the present invention; and

FIG. 3B illustrates a rear perspective view of the fixture mounted on the chain and the guide bar, according to the embodiment of FIG. 3A.

DESCRIPTION OF EMBODIMENTS

The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which example embodiments of the invention incorporating one or more aspects of the present invention are shown. This invention may, 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 invention to those skilled in the art. For example, one or more aspects of the present invention can be utilized in other embodiments and even other types of devices. In the drawings, like numbers refer to like elements.

FIGS. 1 - 3B illustrate various views of a fixture 100 for aiding in filing of a chain of a chain saw. In one embodiment, the fixture 100 aides in manual filing of a cutting link of the chain of the chain saw. In a further embodiment, the fixture guide 100 aides in filing a depth gauge of the chain of the chain saw. The fixture 100 may be made of a plastic, any metal, metallic alloy, or composites. Further, the fixture 100 may be made by one or more suitable processes, for example, moulding, forming, machining, or the like.

A chain saw in general comprises a guide bar on which a chain is engaged. The chain includes various link components, such as a cutting link configured to cut a wood, a depth gauge configured to guide the depth of the cut desired for the chain saw, etc. The disclosure disclosed herein relates to a filing fixture guide 100 for filing the cutting link of the chain of the chain saw.

As illustrated in FIG. 1 , the fixture 100 includes two flanges 102A and 102B (hereinafter collectively referred to as the flanges 102). The flanges 102A and 102B are placed substantially parallel to each other. Further, the flanges 102A and 102B include first ends 104A and 104B, respectively (hereinafter collectively referred to as the first ends 104). Moreover, the flanges 102A and 102B include second ends 106A and 106B, respectively, (hereinafter collectively referred to as the second ends 106). The flanges 102 further include a plurality of recessed portions 118A and 118B (shown in FIGS. 3A and 3B) on the first flange 102A, and 120A and 120B on the second flange 102B. The recessed portions 118A, 118B, 120A and 120B are of shape such that a plurality of portions of a chain 202 may be engaged simultaneously with one or more of these recessed portions 118A, 118B, 120A and 120B, as illustrated in FIGS. 2, 3A and 3B. As will be understood by a person skilled in the art, the shapes of the recessed portions 118A, 118B, 120A and 120B are merely exemplary, and may be varied to achieve similar results.

The recessed portions 118A, 118B, 120A and 120B enable the fixture 100 to be fixed tightly onto the chain saw, and further guide a file 206 to achieve a correct angle for filing a cutting link 204 of the chain 202, as illustrated in FIG. 2. In one embodiment, the file 206 is a round file to enable easy grip of the file 206 and effective filing of the cutting link 204. As will be understood by a person skilled in the art, the shape of the file 206 is merely illustrative, and can be varied to achieve similar results.

As illustrated in FIG. 1 , the fixture 100 includes a first rotatable cylindrical roller 108 connected to the first ends 104 of each of the flanges 102. Additionally, the fixture 100 includes a second rotatable cylindrical roller 110 connected to the second ends 106 of each of the flanges 102. Further, the second rotatable cylindrical roller 108 is placed substantially parallel to the first rotatable cylindrical roller 110. The rotatable cylindrical rollers 108 and 110 are configured to support the file 206 while filing the cutting link 204. The rotatable cylindrical rollers 108 and 110 rotate along the working direction of the file 206 while filing the cutting link 204. As will be understood by a person skilled in the art, the rollers 108 and 110 may be coupled with the flanges 102 using screws, rivets etc.

As illustrated in FIG. 1 , a first connecting portion 111 and a second connecting portion 113 attach the flanges 102 at the first ends 104 and second ends 106, respectively. Further, the first connecting portion 111 includes a pair of counter holds 112 and 114. As illustrated in FIG. 1 , the first connecting portion 113 has an approximately triangular shape with the counter holds 112 and 114 provided along two edges 115 and 117, respectively. Such a configuration ensures that one of the counter holds 112 and 114 contacts a guide bar 208 when the fixture 100 is mounted obliquely relative to the guide bar 208. However, the shape of the first connecting portion 111 is merely exemplary, and may be varied to achieve similar results. In one embodiment, the pair of counter holds 112 and 114 is configured to provide area contact with a guide bar 208 of the chain saw. As illustrated in FIGS. 3B, the counter hold 114 contacts with a guide bar 208 to provide a tight grip of the fixture 100 onto the guide bar 208 of the chain saw. In one embodiment, the counter holds 112 and 114 have rectangular contacting surfaces. In various embodiments, the counter holds 112 and 114 may have a textured surface for improved gripping. However, it will be understood by a person skilled in the art, that the shape of the counter holds 112 and 114 is merely exemplary, and may be varied to achieve similar results. In one embodiment, the counter holds 112 and 114 are integrally formed with the first connecting portion 111. In an alternative embodiment, the counter holds 112 and 114 are attached to the first connecting portion 111 using at least one of welding, riveting, bolting etc. Moreover, the counter holds 112 and 114 may be integral with the first connecting portion 111 , and made by stamping or moulding of the first connecting portion 111.

Further, the fixture 100 includes a cam portion 116 pivotally connected to the second connecting portion 113. The cam portion 116 is configured secure the fixture 100 onto the guide bar 208. The cam portion 116 is twisted to contact the guide bar 208 to secure the fixture 100 between one of the counter holds 112 and 114, and the cam portion 116, onto the guide bar 208 of the chain saw, as illustrated in FIGS. 2, 3A and 3B. Further, the second connecting portion 113 is of a substantially triangular shape with an edge 119 including an indentation 121. The indentation 121 enables the cam portion 116 to extend beyond the edge 119 when the cam portion 116 is twisted to contact the guide bar 208, as illustrated in FIG. 2. Moreover, another edge 123 of the second connecting portion 113 is also dimensioned such that the cam portion 116 extends beyond the edge 123 in an alternate mounting configuration of the fixture 100, as illustrated in FIG. 3B. Thus, the second connecting portion 113 does not interfere with the operation of the cam portion 116. It will be understood by a person skilled in the art, that the shape of the second connecting portion 113 is merely exemplary, and may be varied to achieve similar results.

Further, the cam portion 116 may be extended to form a sheet metal guide 124 configured to enable manual filing of a depth gauge 212 of the chain 202 of the chain saw. In an alternate embodiment, the sheet metal guide 124 may be detachably connected to the cam portion 116 using screws, or rivets etc. However, the sheet metal guide 124 may include more than one cam portions which may be attached using other coupling mechanisms to achieve similar results. The cam portion 116 is illustrated as being protruding from the sheet metal guide 124 to a substantially triangular projection. However, in alternate embodiments, the cam portion 116 may include a curved portion (not shown) extending between the edges of the sheet metal guide 124. The sheet metal guide 124 includes one or more apertures 126 configured to receive the depth gauge 212 of the chain 202. In one embodiment, the shape of the apertures 126 is such that they are complementary with the shape of the depth gauge 212. As will be understood by a person skilled in the art, the shape of the apertures 126 in the sheet metal guide 124 are merely exemplary, and may be varied to achieve similar results. Moreover, the sheet metal guide 124 includes multiple channels 128 to engage a plurality of portions of the chain 202. This enables the sheet metal guide 124 to be secured during filing. Further, in other embodiments of the present invention, the cam portion 116 may be pivotally connected to the fixture 100 by a knuckle joint and made of a suitable material other than the material of the sheet metal guide 124.

For sharpening the chain 202, as illustrated in FIG. 2, the fixture 100 is mounted obliquely relative to the guide bar 208 such that the recessed portions 118A and 120B contact the chain 202. Further, the counter hold 112 contacts the guide bar 208. The cam portion 116 is then twisted to contact the guide bar 208 such the fixture 100 is locked to the guide bar 208 and the chain 202. Thus, the fixture 100 is held tightly onto the guide bar 208 and the chain 202 at four positions, namely, by the recessed portions 118A and 120B, the counter holds 112 and the cam portion 116. The file 206 may be then moved over the cylindrical rollers 108 and 110 to sharpen the cutting link 204 at an optimum angle. As the fixture remains stationary relative to the chain 202 and the guide bar 208 during the filing process, each cutting link 204 is sharpened uniformly and safely.

Alternatively, as illustrated in FIGS. 3A and 3B, the fixture 100 may also be placed obliquely relative to the guide bar 208 such that the recessed portions 118B and 120A contact the chain 202. Further, the counter hold 114 contacts the guide bar 208. In this orientation of the fixture 100, a cutting link 204 located on an opposite side, relative to the cutting link 204 in FIG. 2, may also be sharpened. As illustrated in FIG. 3A, in the secured position, the counter hold 114 maintains an area contact with the guide bar 208. Moreover, as illustrated in FIG. 3B, the cam portion 116 extends beyond the edge 123 of the second connecting portion 113. Thus, the fixture 100 is held tightly onto the guide bar 208 and the chain 202 at four positions, namely, by the recessed portions 118B and 120A, the counter holds 114 and the cam portion 116.

In the drawings and specification, there have been disclosed preferred embodiments and examples of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation of the scope of the invention being set forth in the following claims.