U.S. patent application number 12/967426 was filed with the patent office on 2011-06-23 for backpack power tool.
This patent application is currently assigned to MAKITA CORPORATION. Invention is credited to Yuki MIZUKOSHI, Ryo SUNAZUKA, Kenji WADA.
Application Number | 20110146023 12/967426 |
Document ID | / |
Family ID | 44149050 |
Filed Date | 2011-06-23 |
United States Patent
Application |
20110146023 |
Kind Code |
A1 |
WADA; Kenji ; et
al. |
June 23, 2011 |
BACKPACK POWER TOOL
Abstract
A vibration proofing property is provided in a backpack power
tool. A backpack power tool has a backpack carrying part 103 which
can be carried on user's back, and a tool body 105 mounted on the
backpack carrying part 103. Elastic members 133, 135 are provided
which connect the tool body 105 and a body support region 113 of
the backpack carrying part 103. The elastic members 133, 135 deform
by receiving the weight of the tool body 105 and vibration which is
caused in the tool body 105 by rotation of the rotator 123, and
thereby reduce transmission of the vibration from the tool body 105
to the backpack carrying part 103.
Inventors: |
WADA; Kenji; (Anjo-shi,
JP) ; MIZUKOSHI; Yuki; (Anjo-shi, JP) ;
SUNAZUKA; Ryo; (Anjo-shi, JP) |
Assignee: |
MAKITA CORPORATION
Anjo-Shi
JP
|
Family ID: |
44149050 |
Appl. No.: |
12/967426 |
Filed: |
December 14, 2010 |
Current U.S.
Class: |
15/327.5 ;
15/405 |
Current CPC
Class: |
E01H 1/0809 20130101;
A01G 20/47 20180201; A47L 5/36 20130101; A47L 5/14 20130101; A47L
9/0081 20130101 |
Class at
Publication: |
15/327.5 ;
15/405 |
International
Class: |
E01H 1/08 20060101
E01H001/08 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 18, 2009 |
JP |
2009-287897 |
Claims
1. A backpack power tool comprising: a backpack carrying part
carried on user's back, a tool body mounted on the backpack
carrying part, a rotator provided as a component of the tool body,
a driving mechanism provided as a component of the tool body to
rotationally drive the rotator in a vertical plane, a back contact
region which forms part of the backpack carrying part and contacts
the back of the user, a body support region which forms part of the
backpack carrying part and extends transversely from the back
contact region, and an elastic member which is disposed between the
tool body and the body support region and connects the tool body
and the body support region, wherein the elastic member deforms by
receiving the weight of the tool body and vibration which is caused
in the tool body by rotation of the rotator, and thereby reduces
transmission of the vibration from the tool body to the backpack
carrying part.
2. The backpack power tool according to claim 1, wherein the
elastic member comprises a coil spring, and the coil spring deforms
according to spring constants of the coil spring in a compressing
direction and a shearing direction and thereby reduces transmission
of vibration of the tool body from the tool body to the backpack
carrying part.
3. The backpack power tool according to claim 2, wherein t the coil
spring is arranged such that its central axis extends obliquely
toward an axis of rotation of the rotator with respect to a
vertical direction when the user carries the backpack carrying part
on the back.
4. The backpack power tool according to claim 3, wherein two coil
springs are respectively arranged on right and left sides of a
vertical line passing through the axis of rotation of the
rotator.
5. The backpack power tool according to claim 1, wherein the
rotator is arranged on a near side with respect to the back contact
region of the backpack carrying part which contacts the user's
back, and the driving mechanism is arranged on a far side, wherein
the backpack power tool further includes a rotator housing part
provided as a component of the tool body and having a
circumferential surface for housing the rotator, and wherein the
elastic member is disposed between the circumferential surface of
the rotator housing part and the body support region.
6. The backpack power tool according to claim 1, wherein the
elastic member is arranged with reference to the position of a
center of gravity of the tool body.
7. The backpack power tool according to claim 1, wherein the
rotator comprises an impeller of the blower, and the driving
mechanism comprises an internal combustion engine.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention relates to a backpack power tool which is
carried on user's back and used for a predetermined working
operation.
[0003] 2. Description of the Related Art
[0004] As an example of a backpack power tool, Japanese
non-examined laid-open Patent Publication No. 2008-2310 discloses a
backpack power blower which is used for cleaning operation of
gathering fallen leaves or cut grass. The known backpack power
blower mainly includes a backpack carrying part to be carried on
user's back, and a tool body having an internal combustion engine
and a blower which is driven by the internal combustion engine. The
tool body is mounted on the backpack carrying part via a coil
spring.
[0005] In the above-described known backpack power blower,
vibration caused in tool body when driving the internal combustion
engine is prevent by the coil spring from being transmitted to the
backpack carrying part. In the tool body, however, not only the
driving of the internal combustion engine causes vertical
vibration, but rotation of the blower causes vibration. The
vibration caused by such rotation is not particularly considered in
the known art.
SUMMARY OF THE INVENTION
[0006] Accordingly, it is an object of the invention to improve a
vibration proofing property in a backpack power tool.
[0007] Above-described object can be achieved by the claimed
invention. According to the invention, a representative backpack
power tool is provided which includes a backpack carrying part, a
tool body, a rotator, a driving mechanism, a back contact region, a
body support region, and an elastic member. The backpack carrying
part is carried on user's back. The tool body is mounted on the
backpack carrying part. The rotator is provided as a component of
the tool body. The driving mechanism is provided as a component of
the tool body. The driving mechanism rotationally drives the
rotator in a vertical plane. The back contact region forms part of
the backpack carrying part. The back contact region contacts the
back of the user. The body support region forms part of the
backpack carrying part. The body support region extends
transversely from the back contact region. The elastic member is
disposed between the tool body and the body support region. The
elastic member connects the tool body and the body support region.
The "backpack power tool" according to this invention typically
represents a backpack power blower for use in cleaning operation of
blowing and gathering fallen leaves or cut grass, but it may also
widely include a backpack bush cutter for cutting grass or mowing
lawn, and a backpack power spray for spraying agricultural
chemicals or herbicide.
[0008] According to the invention, the elastic member deforms by
receiving the weight of the tool body and vibration which is caused
in the tool body by rotation of the rotator. Thus, the elastic
member reduces transmission of the vibration from the tool body to
the backpack carrying part. The "rotator" according to the
invention typically represents a blower, and it is preferably
arranged to rotate in a vertical plane. Further, the "driving
mechanism" typically represents an internal combustion engine, but
it also suitably includes an electric motor.
[0009] According to this invention, not only as for vibration
caused by driving of the driving mechanism, but as for vibration
caused in the direction of rotation (the circumferential direction)
by rotation of the rotator, transmission of the vibration from the
tool body to the backpack carrying part can be reduced.
[0010] According to a further aspect of this invention, the elastic
member may comprise a coil spring and the coil spring deforms
according to spring constants of the coil spring in a compressing
direction and a shearing direction (direction of oblique
displacement) and thereby reduces transmission of vibration of the
tool body from the tool body to the backpack carrying part. If the
elastic member is formed, for example, of rubber and arranged to
receive vibration by utilizing its deformation in the shearing
direction, its vibration absorbing effect can be enhanced, but its
durability may be decreased. According to this invention, by using
the coil spring, the vibration absorbing effect can be enhanced by
utilizing its deformation which is caused according to the spring
constant in the shearing direction, while the durability can be
maintained.
[0011] According to a further aspect of this invention, the coil
spring is arranged such that its central axis extends obliquely
toward an axis of rotation of the rotator with respect to the
vertical direction when the user carries the backpack carrying part
on the back. According to this aspect, by such oblique arrangement,
the coil spring can rationally receive vibration caused in the
direction of rotation by rotation of the rotator while receiving
the weight of the tool body, by deforming in the compressing
direction and the shearing direction.
[0012] According to a further aspect of this invention, in the
construction in which the central axis of the coil spring extends
obliquely toward the axis of rotation of the rotator, at least two
coil springs may be arranged on right and left sides of a vertical
line passing through (crossing) the axis of rotation of the
rotator. According to this invention, the coil spring can be
arranged to efficiently proof vibration in consideration of the
balance of vibration.
[0013] According to a further aspect of this invention, the rotator
may be arranged on a near side with respect to the back contact
region of the backpack carrying part which contacts the user's
back, and the driving mechanism maybe arranged on a far side.
Further, a rotator housing part may be provided as a component of
the tool body and has a circumferential surface for housing the
rotator. The elastic member may be disposed between the
circumferential surface of the rotator housing part and the body
support region of the backpack carrying part. According to this
aspect, the elastic member can be arranged closer to the back
contact region, so that vibration transmitted to the backpack
carrying part can be effectively avoided from being amplified in
the body support region and transmitted to the back of the
user.
[0014] According to a further aspect of this invention, the elastic
member may be arranged with reference to the position of a center
of gravity of the tool body. The manner in which the elastic member
is "arranged with reference to the position of a center of gravity"
in this invention represents the manner in which the elastic member
is arranged in a vertical plane containing the center of gravity.
According to this aspect, the vibration proofing function can be
performed in a balanced state in the fore-and-aft direction and the
lateral direction with the backpack power tool carried on the back
of the user.
[0015] According to a further aspect of this invention, the rotator
comprises an impeller of the blower, and the driving mechanism
comprises an internal combustion engine. According to this aspect,
in the backpack power blower for use in cleaning operation of
gathering fallen leaves or cut grass, not only as for vibration
caused by driving of the internal combustion engine, but for
vibration caused in the direction of rotation by rotation of the
impeller of the blower, transmission of the vibration from the tool
body to the backpack carrying part can be reduced.
[0016] According to the invention, a vibration proofing property is
improved in a backpack power tool.
[0017] Other objects, features and advantages of the present
invention will be readily understood after reading the following
detailed description together with the accompanying drawings and
the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a perspective view showing an entire backpack
power tool according to an embodiment of the invention.
[0019] FIG. 2 is a side view of the backpack power tool.
[0020] FIG. 3 is a vertical section of the backpack power tool when
viewed from the rear.
[0021] FIG. 4 is a perspective view showing the backpack power tool
in use.
DETAILED DESCRIPTION OF THE INVENTION
[0022] Each of the additional features and method steps disclosed
above and below may be utilized separately or in conjunction with
other features and method steps to provide and manufacture improved
backpack power tool and method for using such backpack power tool
and devices utilized therein. Representative examples of the
present invention, which examples utilized many of these additional
features and method steps in conjunction, will now be described in
detail with reference to the drawings. This detailed description is
merely intended to teach a person skilled in the art further
details for practicing preferred aspects of the present teachings
and is not intended to limit the scope of the invention. Only the
claims define the scope of the claimed invention. Therefore,
combinations of features and steps disclosed within the following
detailed description may not be necessary to practice the invention
in the broadest sense, and are instead taught merely to
particularly describe some representative examples of the
invention, which detailed description will now be given with
reference to the accompanying drawings.
[0023] A representative embodiment of the invention is now
described with reference to FIGS. 1 to 4. In this embodiment, a
backpack power blower is described as a representative embodiment
of a backpack power tool according to the invention. As shown in
FIGS. 1 and 2, a backpack power blower 101 mainly includes a
backpack carrier 103 which can be carried by a user on the back,
and a power blower 105 which is mounted on the backpack carrier
103. The backpack carrier 103 and the power blower 105 are features
that correspond to the "backpack carrying part" and the "tool
body", respectively, according to the invention.
[0024] The backpack carrier 103 is generally L-shaped in side view
and includes a back pad part (back contact part) 111 which extends
vertically and contacts the back of the user when carried by the
user on the back, and a base 113 which extends horizontally from
the lower end of the back contact part 111 and on which the power
blower 105 is mounted. Each of the back contact part 111 and the
base 113 has a frame structure formed by bending a pipe into a
generally square shape. The back contact part 111 and the base 113
are features that correspond to the "back contact region" and the
"body support region", respectively, according to the invention. As
shown in FIG. 5, the backpack carrier 103 further includes a
backpack carrying band 115 and is carried on the back of the user
via the backpack carrying band 115. The backpack carrying band 115
is designed to be detachable from the back contact part 111. In the
following description, for the sake of convenience of explanation,
the side of the back contact part 111 (the left side as viewed in
FIG. 2) is taken as the front and the extending side (the right
side as viewed in FIG. 2) of the base 113 extending from the end of
the back contact part 111 as the rear.
[0025] The power blower 105 mainly includes a blower 121 and an
internal combustion engine 131 that rotationally drives the blower
121. The internal combustion engine 131 is a feature that
corresponds to the "driving mechanism" according to this invention.
As shown in FIG. 3, the blower 121 includes an impeller
(hereinafter referred to as a blower fan) 123 and a housing 125
that houses the blower fan 123. The blower fan 123 and the housing
125 are features that correspond to the "rotator" and the "rotator
housing part", respectively, in this invention.
[0026] An air blowoff pipe 128 is connected to an air outlet port
125a formed in the housing 125, via an elbow pipe 126 and a
bellows-like flexible pipe 127. As shown in FIGS. 1 and 2, an
operating member in the form of a handgrip 129 for operating the
blowoff pipe 128 is provided on the blowoff pipe 128. By holding
the handgrip 129 and operating a control member of the internal
combustion engine 131 and the blowoff pipe 128, the user can
perform an operation of blowing and gathering fallen leaves or cut
grass by air which is blown out through an outlet port 128a of the
blowoff pipe 128.
[0027] As shown in FIGS. 1 and 2, the blower 121 and the internal
combustion engine 131 are arranged one behind the other, or with
the internal combustion engine 131 behind the blower 121. At least
outer shell components (housings) of the blower 121 and the
internal combustion engine 131 are formed in one piece.
[0028] A vibration proofing structure of the power blower 105 which
is mounted on the backpack carrier 103 is now described. The
vibration proofing structure according to this embodiment mainly
includes a plurality of (two) coil springs 133, 135 disposed
between the base 113 of the backpack carrier 103 and the power
blower 105. The coil springs 133, 135 are features that correspond
to the "elastic member" in this invention. The coil springs 133,
135 deform by receiving the weight of the power blower 105 and
vibration caused in the power blower 105 and can thereby reduce or
prevent transmission of the vibration from the power blower 105 to
the backpack carrier 103.
[0029] In this embodiment, the two coil springs 133, 135 deform
according to the spring constants in the compressing direction and
in the shearing direction of the coil springs and thereby reduce or
prevent transmission of vibration which is caused when the power
blower 105 is driven, to the backpack carrier 103. Specifically, as
shown in FIG. 3, the two coil springs 133, 135 are arranged in
symmetry with respect to a vertical line P extending vertically
through (across) a rotary shaft 123a of the blower fan 123 and
arranged such that the central axes of the coil springs 133, 135
extend obliquely toward the axis of rotation (the rotary shaft
123a) of the blower fan 123 (such that the central axes form an
inverted V-shape when viewed from the front or the rear). By such
arrangement, the right and left coil springs 133, 135 receive
vertical vibration caused by driving of the internal combustion
engine 131 and vibration caused in the direction of rotation (the
circumferential direction) by rotation of the blower fan 123 of the
blower 121 while supporting the weight of the power blower 105 and
thereby deform in the compressing direction and in the shearing
direction (the direction of oblique displacement). By such
deformation, transmission of the vibration from the power blower
105 to the backpack carrier 103 can be reduced or prevented.
[0030] The right and left coil springs 133, 135 are disposed
between the upper surface of the base 113 of the backpack carrier
103 and the lower surface of the circumferential surface region of
the housing 125 which houses the blower fan 123. The coil springs
133, 135 are fastened at one axial end to the upper surface of the
base 113 via spring receiving bracket 133a, 135a and at the other
end to the lower surface of the housing 125 via spring receiving
bracket 133b, 135b.
[0031] Further, one coil spring (not shown) is disposed generally
in the middle in the lateral direction (on a vertical line passing
through (crossing) the axis of rotation of the blower fan 123)
between a rear surface of an upper end portion of the back contact
part 111 of the backpack carrier 103 and a front surface of an
upper end portion of the housing 125 of the blower 121 and arranged
such that the central axis of the coil spring extends generally
horizontally in the fore-and-all direction. Specifically, the power
blower 105 is supported at two points on the base 113 and one point
on the back contact part 111 by the coil springs 133, 135, and it
is held contactless at any other points with respect to the
backpack carrier 103.
[0032] In this embodiment, the power blower 105 is mounted on the
backpack carrier 103 via the coil springs 133, 135, and the coil
springs 133, 135 deform by receiving the weight of the power blower
105 and vibration caused in the direction of rotation by rotation
of the blower fan 123 and can thereby prevent transmission of the
vibration from the power blower 105 to the backpack carrier 103.
Further, in this embodiment, the coil springs 133, 135 are arranged
such that the central axes of the coil springs 133, 135 extend
obliquely toward the axis of rotation of the blower fan 123. With
this arrangement, the coil springs 133, 135 can deform in the
compressing direction and in the shearing direction and thereby
absorb vertical vibration caused by driving of the internal
combustion engine 131 and vibration caused in the direction of
rotation by rotation of the blower fan 123, so that transmission of
the vibration from the power blower 105 to the backpack carrier 103
can be reduced.
[0033] Further, in this embodiment, it is constructed such that
vibration is absorbed by deformation of the coil springs 133, 135
in the compressing direction and in the shearing direction. If the
vibration-proofing member is formed, for example, of rubber and
arranged to receive vibration by utilizing its deformation in the
shearing direction, its vibration absorbing effect can be enhanced,
but its durability may be decreased. According to this invention,
by using the coil springs 133, 135, the vibration absorbing effect
can be enhanced by utilizing deformation which is caused according
to the spring constant in the shearing direction, while the
durability can be maintained.
[0034] In this embodiment, the two coil springs 133, 135 are
arranged in symmetry with respect to the vertical line P extending
through the axis of rotation of the blower fan 123. Therefore, the
weight of the power blower 105 and vibration caused by driving the
power blower 105 can be received in a balanced manner in the
lateral direction. Such a symmetrical arrangement is effective, for
example, if the center of gravity of the power blower 105 lies on
the vertical line P. Actually, however, the center of gravity of
the power blower 105 may be displaced to the right or the left off
the vertical line P. Therefore, in such a case, preferably, the two
coil springs 133, 135 are arranged in a position to achieve right
and left weight balance with respect to the vertical line P, so
that efficient vibration proofing can be realized.
[0035] Further, vibration is not always caused in the same manner
on the right and left sides of the vertical line P. For example,
the manner of vibration on the side having the air outlet port 125a
differs from that on the other side not having the air outlet port
125a. Further, the direction of vibration acting on the left coil
spring 133 differs from that on the right coil spring 135 according
to the direction of rotation of the blower fan 123 (In FIG. 3,
because the blower fan 123 rotates clockwise, vibration acts upward
on the left coil spring 133 and downward on the right coil spring
135). Therefore, preferably, the right and left coil springs 133,
135 are adjusted in position and angle and disposed such that
efficient vibration proofing can be achieved by receiving vibration
evenly on the right and left sides.
[0036] Further, in this embodiment, the blower 121 and the internal
combustion engine 131 are arranged one behind the other, or with
the internal combustion engine 131 behind the blower 121, and the
circumferential surface of the housing 125 of the blower 121 is
supported by the coil springs 133, 135. With this construction, the
distance from the back contact part 111 of the backpack carrier 103
to the coil springs 133, 135 can be made shorter, for example,
compared with a construction in which the coil springs 133, 135
support the internal combustion engine 131. Therefore, vibration
transmitted to the base 113 of the backpack carrier 103 can be
avoided from being amplified at the base 113 and transmitted to the
back of the user, and heat generated in the internal combustion
engine 131 can also be avoided from adversely affecting the
user.
[0037] The invention is not limited to the above-described
embodiment, but can be appropriately modified or changed. For
example, in this embodiment, the circumferential surface of the
housing 125 of the blower 121 is supported by the coil springs 133,
135, but it may be modified such that the coil springs 133, 135 are
arranged in symmetry with respect to a vertical line passing
through the center of gravity of the power blower 105. In this
case, the weight of the power blower 105 and vibration caused by
driving the power blower 105 can be received not only in the
lateral direction but in the fore-and-aft direction in a balanced
manner.
[0038] Further, in this embodiment, the base 113 is formed to
extend rearward from the lower edge of the back contact part 111,
and the power blower 105 is mounted on the upper surface of the
base 113. It may however be modified, for example, such that a
support part is formed to extend rearward from the upper edge of
the back contact part 111 and the power blower 105 is hung and
supported via the coil springs 133, 135 with respect to the support
part. In this case, preferably, the coil springs 133, 135 are
arranged in symmetry with respect to the vertical line P passing
through the axis of rotation of the blower fan 123 such that the
central axes of the coil springs extend obliquely toward each other
to form a V-shape when viewed from the front or the rear. Further,
the means for driving the blower 121 may be an electric motor in
place of the internal combustion engine 131.
[0039] Further, in this embodiment, the backpack power blower is
described as a representative example of the backpack power tool
according to the invention. However, the invention can be applied
not only to the backpack power blower, but to a backpack bush
cutter for cutting grass or mowing lawn, or a backpack power
sprayer for spraying agricultural chemicals or herbicide.
DESCRIPTION OF NUMERALS
[0040] 101 backpack power blower [0041] 103 backpack carrier
(backpack carrying part) [0042] 105 power blower (tool body) [0043]
111 back contact part (back contact region) [0044] 113 base (body
support region) [0045] 115 backpack carrying band [0046] 121 blower
[0047] 123 blower fan (rotator) [0048] 123a rotary shaft [0049] 125
housing [0050] 125a outlet port [0051] 126 elbow pipe [0052] 127
flexible pipe [0053] 128 blowoff pipe [0054] 128a outlet port
[0055] 129 handgrip [0056] 131 internal combustion engine (driving
mechanism) [0057] 133 coil spring (elastic member) [0058] 135 coil
spring (elastic member) [0059] 133a, 133b spring receiving bracket
[0060] 135a, 135b spring receiving bracket
* * * * *