BACKGROUND OF THE INVENTION
(1) Field of the Invention
[0001] The present invention relates to a guide bar of a chain saw used for felling, cutting,
or the like of trees, for example.
(2) Description of Related Art
[0002] Chain saws are operated by workers and used for felling, cutting, or the like of
trees, for example. Conventionally, it has been sought to reduce the weight of the
guide bar of chain saws for the purpose of improving the usability of the chain saws
for the workers.
[0003] Fig. 5 is a front view showing a main part of a conventional guide bar (see
JP 2016-155351 A). The guide bar has an elongated plate-shaped guide bar body 51 in which a guide
groove 54 for guiding a saw chain is formed along the outer periphery. The guide bar
body 51 has elongated holes 52a and 52b on both sides of a central axis line CL, and
an attachment member 53 made of a light-weight component such as synthetic resin is
attached to each of the elongated holes 52a and 52b to reduce weight.
SUMMARY OF THE INVENTION
[0004] Further, in the configuration shown in Fig. 5, the guide bar body 51 has a beam portion
f51 extending in the longitudinal direction of the guide bar body 51 and a beam portion
f52 extending in the width direction of the guide bar body 51 in each of the long
holes 52a and 52b to improve rigidity. However, there is room for improvement in increasing
rigidity.
[0005] The present invention has been made to solve the above-described problems, and an
object of the present invention is to provide a guide bar of a chain saw that can
reduce weight and increase rigidity.
[0006] In order to achieve the above object, a guide bar of a chain saw according to an
embodiment is a guide bar used for a chain saw including: an elongated plate-shaped
guide bar body that supports a saw chain on a peripheral edge portion thereof; a hole
penetrating the guide bar body; and a filler filling the hole. The guide bar body
has a reinforcement portion that includes a beam portion tilted with respect to a
central axis line that extends in a longitudinal direction of the guide bar body,
and connecting two parts of a side wall of the hole.
[0007] The present invention has the above-described configuration, and has an effect of
providing a guide bar of a chain saw that can reduce weight and increase rigidity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008]
Fig. 1A is a front view showing a guide bar of a chain saw of a first configuration
example of the embodiment, and Fig. 1B is an enlarged view of a cross-sectional portion
taken along line A-A of Fig. 1A;
Fig. 2 is a front view showing a main part of a guide bar of a chain saw of a second
configuration example of the embodiment;
Fig. 3 is a front view showing a main part of a guide bar of a chain saw of a third
configuration example of the embodiment;
Fig. 4A is a front view showing a guide bar of a chain saw of a fourth configuration
example of the embodiment, and Fig. 4B is a front view showing a guide bar body before
filling a filler in the guide bar of Fig. 4A; and
Fig. 5 is a front view showing a main part of a conventional guide bar.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0009] Hereinafter, embodiments of the present disclosure will be described with reference
to the accompanying drawings.
[0010] Each embodiment described below shows a specific example of the present disclosure.
Numerical values, shapes, materials, components, arrangement positions and connection
forms of components, and the like shown in the following embodiments are merely examples,
and do not limit the present disclosure.
[0011] In addition, the same or corresponding elements are denoted by the same reference
numerals throughout all the drawings, and redundant description thereof may be omitted.
In addition, the drawings schematically show each component for easy understanding,
and the shape, dimensional ratio, and the like may be inaccurate in some cases.
(Embodiment)
[0012] A guide bar of a chain saw of the embodiment is a guide bar used for a chain saw
including: an elongated plate-shaped guide bar body that supports a saw chain on a
peripheral edge portion thereof; a hole penetrating the guide bar body; and a filler
filling the hole. The guide bar body has a reinforcement portion that includes a beam
portion tilted with respect to a central axis line that extends in a longitudinal
direction of the guide bar body, and connecting two parts of a side wall of the hole.
[0013] According to this configuration, it is possible to reduce weight by providing a hole
in the guide bar body and filling the hole with a filler having a lower density than
the guide bar body. Furthermore, since the beam portion placed in the hole is tilted
with respect to the central axis line extending in the longitudinal direction of the
guide bar body, flexural rigidity and torsional rigidity can be improved.
[0014] In the guide bar, the reinforcement portion may have two of the beam portions tilted
in opposite directions with respect to the central axis line of the guide bar body,
the two beam portions intersecting each other.
[0015] In the guide bar, multiple holes may be provided, and the guide bar body may have
the reinforcement portion for to two or more of the holes.
[0016] In the guide bar, the periphery of the beam portion may be covered with the filler.
[0017] In the guide bar, the hole is one hole that is long in the longitudinal direction
and that is provided to the guide bar body; the guide bar body may have one or more
separation portions extending in a width direction of the guide bar body from a side
wall of the hole to separate the hole into a plurality of regions in the longitudinal
direction of the guide bar body, the reinforcement portion included in the region
separated by the separation portion; and the periphery of the beam portion and the
separation portion may be covered with the filler.
[0018] In the guide bar, the guide bar body may further have a projecting portion extending
inward from a side wall of the hole, and the periphery of the projecting portion may
be covered with the filler.
[First Configuration Example]
[0019] Fig. 1A is a front view showing a guide bar of a chain saw of a first configuration
example of the embodiment, and Fig. 1B is an enlarged view of a cross-sectional portion
taken along line A-A of Fig. 1A. Note that in the guide bar shown in Fig. 1A, the
arrow x direction is the longitudinal direction, and the arrow y direction is the
width direction. Additionally, a direction perpendicular to the arrow x and y directions
(sheet depth direction of Fig. 1A) is the thickness direction.
[0020] The guide bar includes an elongated plate-shaped metal guide bar body 1, multiple
holes (hereinafter referred to as "filling holes") 2a and 2b penetrating the guide
bar body 1 and long in the longitudinal direction of the guide bar body 1, and fillers
3 and 3 filling the filling holes 2a and 2b. Note that the filler 3 is formed of a
synthetic resin having a lower density than the guide bar body 1. The filler 3 can
be formed by injection molding, for example. Additionally, as in
JP 2016-155351 A described above, the filler 3 may be formed by attaching the attachment member 53
(see Fig. 5) molded in advance.
[0021] A base end portion 1R of the guide bar body 1 has appropriate holes 5 to 7, for example,
for engaging with a chain saw body (not shown), and can be attached to the chain saw
body. Additionally, a guide groove 4 (Fig. 1B) for guiding a saw chain (not shown)
is formed along the outer periphery of the guide bar body 1. That is, the saw chain
is supported on a peripheral edge portion of the guide bar body 1. The guide bar body
1 does not have a sprocket at the tip end, but may have a sprocket at the tip end.
[0022] In the guide bar body 1, the filling holes 2a and 2b are formed symmetrically with
respect to the central axis line CL extending in the longitudinal direction of the
guide bar body 1. Hence, there is good balance. However, the shape, number, arrangement,
and the like of the filling holes can be changed as appropriate.
[0023] Additionally, the guide bar body 1 has a reinforcement portion including two beam
portions f1 and f2 in one filling hole 2a. Each of the beam portions f1 and f2 extends
linearly so as to connect two parts of a side wall (inner wall) of the filling hole
2a. Additionally, the two beam portions f1 and f2 are tilted in opposite directions
with respect to the central axis line CL of the guide bar body 1 and intersect each
other (intersection fx). Additionally, the guide bar body 1 has a projecting portion
t1 extending inward from a central portion in the thickness direction of the side
wall (inner wall) of the filling hole 2a. The projecting portion t1 is formed over
the entire periphery of the filling hole 2a, and is partially shared with the beam
portions f1 and f2. The beam portions f1 and f2 and the projecting portion t1 have
the same thickness and pass through the central portion in the thickness direction
of the guide bar body 1, and the periphery thereof is covered with the filler 3.
[0024] Similarly, the guide bar body 1 has a reinforcement portion including two beam portions
f3 and f4 in the other filling hole 2b. Each of the beam portions f3 and f4 extends
linearly so as to connect two parts of a side wall (inner wall) of the filling hole
2b. Additionally, the two beam portions f3 and f4 are tilted in opposite directions
with respect to the central axis line CL of the guide bar body 1 and intersect each
other. Additionally, the beam portions f3 and f4 pass through the central portion
in the thickness direction of the guide bar body 1, and the periphery thereof is covered
with the filler 3.
[0025] The filling hole 2b, too may have a projecting portion similar to the projecting
portion t1 in the filling hole 2a. Such a projecting portion may be provided in one
or both of the two filling holes 2a and 2b. Additionally, the projecting portion may
be omitted from both of the filling holes 2a and 2b. Moreover, while the above-described
projecting portion t1 is provided over the entire periphery of the filling holes 2a
and 2b, the projecting portion t1 may be spaced apart in the circumferential direction
of the filling hole and divided into multiple parts. By providing the projecting portion
t1, the filler 3 is held stronger, and the effect of preventing the filler 3 from
peeling off can be improved during use of the chain saw, for example.
[0026] In the guide bar body 1, through-holes are formed by laser machining or press working
in regions inside the filling holes 2a and 2b and except for the beam portions f1,
f2, f3, and f4, and the projecting portion t1, and then the beam portions f1, f2,
f3, and f4, and the projecting portion t1 are formed by cutting, for example.
[0027] In the first configuration example, it is possible to reduce weight by providing
the filling holes 2a and 2b in the guide bar body 1 and filling each of the filling
holes 2a and 2b with the filler 3 having a lower density than the guide bar body 1.
Further, the beam portions f1, f2, f3, and f4 placed in the filling holes 2a and 2b
are tilted with respect to the central axis line CL extending in the longitudinal
direction of the guide bar body 1. As a result, it is possible to increase flexural
rigidity against a force that bends a tip end portion of the guide bar body 1 fixed
to the chain saw body in an arrow a direction with respect to the base end portion
1R thereof, and also increase torsional rigidity against a force that twists the tip
end portion in an arrow b direction with respect to the base end portion 1R.
[Second Configuration Example]
[0028] Fig. 2 is a front view showing a main part of a guide bar of a chain saw of a second
configuration example of the embodiment.
[0029] The guide bar of the second configuration example is different from the guide bar
of the first configuration example in that in a guide bar body 1, one filling hole
2a omits the projecting portion t1, but has a beam portion f5 extending in the longitudinal
direction of the guide bar body 1 and a beam portion f6 extending in the width direction
thereof. Hence, rigidity can be improved even more. Note that other configurations
are similar to those of the first configuration example.
[Third Configuration Example]
[0030] Fig. 3 is a front view showing a main part of a guide bar of a chain saw of a third
configuration example of the embodiment.
[0031] The guide bar of the third configuration example is different from the guide bar
of the first configuration example in that two filling holes 2c and 2d formed symmetrically
with respect to a central axis line CL of a guide bar body 1 are provided instead
of one filling hole 2a. Then, the guide bar body 1 has a beam portion f7 as a reinforcement
portion in the filling hole 2c, and a beam portion f8 as a reinforcement portion in
the filling hole 2d. Other configurations are similar to those of the first configuration
example.
[0032] The beam portions f7 and f8 extend linearly so as to connect two parts of a side
wall (inner wall) of the filling holes 2c and 2d. Additionally, the beam portions
f7 and f8 are tilted with respect to the central axis line CL of the guide bar body
1. As a result, flexural rigidity can be increased and torsional rigidity can also
be increased as in the case of the beam portions f1 to f4 and the like of the first
configuration example.
[0033] In the first to third configuration examples, the guide bar body 1 has the reinforcement
portion including the beam portion tilted with respect to the central axis line CL
of the guide bar body 1 in each of the multiple filling holes. However, by providing
the beam portion tilted with respect to the central axis line CL in at least one filling
hole, flexural rigidity can be increased and torsional rigidity can also be increased.
For example, a configuration may be adopted in which the guide bar body 1 has only
one filling hole, and the filling hole has only one beam portion (reinforcement portion)
tilted with respect to the central axis line CL. Moreover, in addition to the filling
hole having such a reinforcement portion, a filling hole having no reinforcement portion
may be provided from the viewpoint of weight reduction. The shape, number, arrangement,
and the like of the filling holes can be changed as appropriate.
[0034] Also, by providing a projecting portion such as the projecting portion t1 of the
first configuration example in each filling hole (2a to 2d) in the second and third
configuration examples, the effect of preventing the filler 3 from peeling off can
be improved during use of the chain saw, for example.
[Fourth Configuration Example]
[0035] Fig. 4A is a front view showing a guide bar of a chain saw of a fourth configuration
example of the embodiment, and Fig. 4B is a front view showing a guide bar body before
filling a filler in the guide bar of Fig. 4A.
[0036] As shown in Fig. 4A, the guide bar of the fourth configuration example includes,
as a hole for filling a filler 3, only one filling hole 2 that is long in the longitudinal
direction of a guide bar body 1. Of the filling hole 2, a part on the side close to
a base end portion 1R of the guide bar body 1 is separated in the width direction
of the guide bar body 1 by a central separation portion 1a of the guide bar body 1.
[0037] As shown in Fig. 4B, as in the case of the projecting portion t1 of the first configuration
example, the guide bar body 1 has a projecting portion t2 extending inward from a
central portion in the thickness direction of a side wall of the filling hole 2. The
projecting portion t2 is formed over the entire periphery of the filling hole 2, and
is partially shared with beam portions f11 to f16 and separation portions f21 to f23
described later.
[0038] Further, the guide bar body 1 has the separation portions f21 to f23 extending in
the width direction of the guide bar body 1 from the central portion in the thickness
direction of the side wall of the filling hole 2. The filling hole 2 is separated
into multiple regions r1 to r5 in the longitudinal direction of the guide bar body
1 by the separation portions f21 to f23. Then, the regions r1 to r5 separated by the
separation portions f21 to f23 include therein the linearly extending beam portions
f11 to f16 as reinforcement portions, respectively.
[0039] As in the case of the beam portions f1 and f2 and the projecting portion t1 of the
first configuration example, the beam portions f11 to f16, the separation portions
f21 to f23, and the projecting portion t2 have the same thickness and pass through
the central portion in the thickness direction of the guide bar body 1, and the periphery
thereof is covered with the filler 3.
[0040] In the fourth configuration example, since the beam portions f11 to f16 as reinforcement
portions are provided, flexural rigidity can be increased and torsional rigidity can
also be increased, as in the case of the first to third configuration examples.
[0041] Additionally, since only one filling hole 2 is provided, when filling the filler
3 by resin injection molding, for example, the resin can be filled from one injection
port of an injection molding machine. Hence, compared with a case of filling multiple
filling holes from multiple injection ports, uniform filling without variation can
be performed.
[0042] Although the projecting portion t2 can be omitted from the fourth configuration example,
by providing the projecting portion t2, the filler 3 is held stronger, and the effect
of preventing the filler 3 from peeling off can be improved during use of the chain
saw, for example. Note that the projecting portion t2 may be spaced apart in the circumferential
direction of the filling hole 2 and divided into multiple parts.
[0043] In the embodiment, the beam portions (f1 to f4, f7, f8, and f11 to f16) forming the
reinforcement portion are tilted with respect to the central axis line CL of the guide
bar body 1, unlike the beam portion such as the beam portion f51 of Fig. 5 having
a center line parallel to or coinciding with the central axis line CL of the guide
bar body 51, or the beam portion such as the beam portion f52 of Fig. 5 having a center
line intersecting with the central axis line CL. Hence, an even greater effect can
be obtained in increasing rigidity.
[0044] The above-mentioned beam portion forming the reinforcement portion being tilted with
respect to the central axis line CL of the guide bar body 1 means that the center
line of the same beam portion (straight line extending in extending direction of same
beam portion) and the central axis line CL of the guide bar body 1 intersect at an
oblique angle (intersect at angle other than right angle). For example, in the case
of the beam portions f1 and f2 in Fig. 1, an angle θ1 formed by a center line C1 of
the beam portion f1 and the central axis line CL is 0° < θ1 < 90°, and similarly,
an angle θ2 formed by a center line C2 of the beam portion f2 and the central axis
line CL is 0° < θ2 < 90°. The same applies to the beam portions (f3, f4, f7, f8, and
f11 to f16) forming the other reinforcement portions.
[0045] Additionally, one end or both ends of a beam portion forming a reinforcement portion
may be in the middle of the filling hole in which the beam portion is formed, instead
of both ends in the longitudinal direction of the guide bar body 1. For example, a
configuration may be adopted in which multiple pairs of beam portions in the form
of a cross shape formed of the beam portion f1 and the beam portion f2 shown in Fig.
1A are provided side by side in one filling hole. The multiple pairs of beam portions
may arranged along the longitudinal direction or the width direction of the guide
bar body 1.
[0046] Note that while the filling holes 2 and 2a to 2d of the embodiment are long in the
longitudinal direction of the guide bar body 1, the shape of the filling hole is not
limited to this. The shape of the filling hole may be a square, a circle, or a triangle,
for example.
[0047] From the foregoing description, many modifications and other embodiments of the present
invention are obvious to one skilled in the art. Accordingly, the foregoing description
should be construed as illustrative only and is provided for the purpose of teaching
those skilled in the art the best mode of carrying out the invention. Details of the
structure and/or function of the invention can be substantially changed without departing
from the spirit of the invention.
[0048] The present invention is useful as a guide bar of a chain saw, for example, that
can reduce weight and increase rigidity.